JPS62204055A - Direct coupling mechanism control method for fluid type power transmission of automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To suppress generation of vibration and noise from a car body by controlling accurately the transmission capacity without causing scattering even in case the transmission capacity of a direct coupling mechanism is set to a stronger value. CONSTITUTION:A certain parameter to represent relative slip amount of an input and an output member of a torque converter, for ex. measurement of the rotational speed ratio e, is compared with a previously specified reference range value, and the result therefrom should determine the transmission capacity of a direct coupling mechanism (direct coupling clutch) for specified periods of time T1, T2, T3 to be carried out from now. In case, for ex., the transmission capacity is controlled by a solenoid valve, the control is made upon duty ratios D0-D20 of the solenoid. A fine adjustment formula is established in contact with the above side of the above-mentioned specified reference range value, and the transmission capacity is fine adjusted toward the reduction side when the parameter exceeds the specified reference range value.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for controlling a direct coupling mechanism of a fluid power transmission device for an automatic transmission for a vehicle.

(Prior art and its problems) In general, vehicles equipped with automatic transmissions use a fluid power transmission device, such as a fluid torque converter, to provide sufficient driving force and a smooth and easy driving feeling with a small number of gears. On the other hand, the practical fuel efficiency is poor due to the fluid slippage loss in the torque converter, and the engine rotational speed increases by the amount of fluid slippage, making the engine noisy and lacking in lightning quieting properties.

For this reason, when there is no need to expect the torque amplification function of the torque converter, a direct coupling clutch mechanism called a lock-up mechanism is used, which mechanically connects the torque converter's output member and the output member to improve power transmission efficiency. (
A direct-coupling mechanism (hereinafter referred to as a direct-coupling mechanism) has been developed and has already been put into practical use, and since it can obtain favorable effects from improving power transmission characteristics and fuel efficiency, the direct-coupling mechanism is operated from as low a speed range as possible. It is desirable to do so. However, if the torque converter is completely directly connected in the low-speed operating range where the engine speed is also low, there are drawbacks such as large fluctuations in engine torque, which may cause vibration and noise in the vehicle body, or deteriorate driving performance. .

Therefore, instead of directly connecting the torque converter in such a low-speed operating range, for example, the rotational speed of the input member and output member of the torque converter should be Calculate the ratio e or slip ratio (=1-8), etc., and in the above low speed operating range, the rotation speed ratio e is 1 or the slip ratio is 0.
The transmission capacity of the direct coupling mechanism is controlled by adopting the optimum transmission capacity from among the plurality of transmission capacities (engaging forces) of the direct coupling mechanism while feeding back the actual measured value of the rotational speed ratio e or slip ratio so as to avoid this. It is possible that

However, when such a control method is implemented, the following problems occur. That is, for example, in an embodiment of the present invention to be described later, the transmission capacity is the maximum capacity of the control system when the electromagnetic valve that controls the transmission capacity is off, that is, when the valve is closed.

) is set relatively weakly, the control is performed smoothly and no vibration or noise is generated in the vehicle body, but the fuel consumption is poor (or, conversely, in order to improve fuel efficiency, the transmission When the capacity is set relatively strong, the rotation speed ratio e sometimes becomes 1.
, or the slip ratio approaches O, or the rotational speed ratio e=1 or the slip ratio becomes -0, causing vibrations and noise in the vehicle body.

This is because no matter how electronic control technology is used, calculating the rotational speed ratio e or slip ratio takes a certain amount of time, including data sampling time, and the feedback system includes mechanical parts such as hydraulic equipment. , there is a physical limit to the response time of the control system that cannot be accelerated beyond a certain value, but if the transmission capacity is set to be strong, the transition to the direction of direct coupling (increasing the transmission capacity) is possible. As the speed increases, there is a delay in control and the rotational speed ratio e or slip ratio exceeds the standard range value, and in order to reflect this result and return it to the standard range value, the transmission capacity is increased more than necessary. Since control is started to decrease the rotational speed ratio e or the slip ratio, the rotational speed ratio e or the slip ratio decreases again to be below the reference range value, which is repeated, and in the worst case, it diverges.

Note that if the response time of the entire control system is shortened, there is no risk of the above-mentioned problem occurring even when the transmission capacity is set to be strong, but in reality, there is a limit to the shortening of the response time.

(Object of the Invention) The present invention has been made in view of the above circumstances, and is an operating range in which it is necessary to accurately control the transmission capacity without causing divergence even when the transmission capacity of the direct coupling mechanism is set to be strong. We control this to the optimum value to suppress vehicle body vibration and noise, as well as improve fuel efficiency and power transmission characteristics.
Another object of the present invention is to provide a direct-coupling mechanism control method for a fluid power transmission device of an automatic transmission for a vehicle, which allows an extremely smooth and comfortable driving feeling to be obtained.

(Means for Solving the Problems) In order to solve the above-mentioned problems, in the present invention, predetermined actual values and preset values of predetermined parameter values representing the relative slip amounts of the output member and the output member of the hydraulic power transmission device are provided. Based on the comparison result, determine the transmission capacity of the direct coupling mechanism for a predetermined period to be implemented from now on, and when the parameter value is greater than or equal to the predetermined reference range value, determine the transmission capacity. A fine adjustment area for making fine adjustments to the decreasing side is provided above and in contact with the predetermined reference range value.

(Example) An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an outline of a vehicle automatic transmission to which the present invention can be applied, in which the output of the engine E is transmitted from its crankshaft 1 to a torque converter T as a fluid power transmission device, an auxiliary transmission M, and a differential device Dr. The diameter of the left and right drive wheels w, w'
and drive them.

The torque converter T includes a pump impeller 2 which is an input member connected to a crankshaft 1, a turbine impeller 4 which is an output member connected to an input shaft 3 of an auxiliary transmission M, and a rotatable member on the input shaft 3. The stator wheel 5 is connected to a stator shaft 5a supported by a stator shaft 5a via a one-way clutch 6. The torque transmitted from the crankshaft 1 to the pump wheel 2 is hydrodynamically transmitted to the turbine wheel 4, and when the torque is amplified during this time, the stator wheel 5 acts as a reaction force. bear the burden.

A pump drive gear 7 for driving the hydraulic pump P shown in FIG. 2 is provided at the right end of the pump impeller 2, and a stator shaft 5a
A stator arm 5b that controls the regulator valve Vr shown in FIG. 2 is fixed to the right end of the stator arm 5b.

A roller-type direct coupling clutch Cd is provided between the pump impeller 2 and the turbine impeller 4 as a direct coupling mechanism capable of mechanically coupling these. To explain this in detail with reference to FIGS. 2 and 3, an annular drive member 9 having a drive conical surface 8 on the inner circumference is spline-fitted to the inner peripheral wall 2a of the pump impeller 2.

Further, an annular driven member 11 having a driven conical surface 10 facing parallel to the driving conical surface 8 on its outer periphery is spline-fitted to the inner circumferential wall 4a of the turbine impeller 4 so as to be slidable in the axial direction. . A piston 12 is integrally formed at one end of this driven member 11, and this piston 12 is slidably engaged with a hydraulic cylinder 13 provided on the inner circumferential wall 4a of the turbine impeller 4.
The internal pressure of the cylinder 13 and the internal pressure of the torque converter T are simultaneously received on both left and right end surfaces.

A cylindrical clutch roller 14 is interposed between the driving and driven conical surfaces 8 and 10, and this clutch roller 14
As shown in the figure, the annular retainer 15 is arranged so that its central axis O is inclined at a constant angle θ with respect to the generatrix g of the virtual circle 5ff1 surface 1c (see FIG. 2) passing through the center between the hundred conical surfaces 8 and 10. is maintained by

Therefore, when a hydraulic pressure higher than the internal pressure of the torque converter T is introduced into the hydraulic cylinder 13 at a stage when the torque amplification function of the torque converter T is no longer required, the piston 12, that is, the driven member 11 is pushed toward the drive member 9. Ru. As a result, the clutch roller 14 is pressed against the 100-conical surfaces 8 and 10. At this time, when the driving member 9 is rotated in the X direction in FIG. 3 with respect to the driven member 11 by the output torque of the engine E, the clutch roller 14 rotates. Since 0 is tilted as described above, its rotation imparts a relative axial displacement to both members 9.11 that brings them closer together. As a result, the clutch roller 14 has a hundred conical surface 8.10
It bites in between the two members 9 and 11, that is, the pump wheel 2 and the turbine wheel 4 to be mechanically connected. Even during such operation of the direct coupling clutch Cd, if the output torque of the engine E exceeds the coupling force and is applied between the two wing wheels 2.4, the clutch roller 14 will slip against each conical surface 8, 10. The above torque is divided into two parts, and a part of the torque is transmitted mechanically through the direct coupling clutch Cd, and the remaining torque is transmitted hydrodynamically from the pump wheel 2 to the turbine wheel 4. , the ratio of the former torque to the latter torque changes depending on the degree of slippage of the clutch roller 14.

If a reverse load is applied to the torque converter T in the operating state of the direct coupling clutch Cd, the rotational speed of the driven member 11 becomes higher than the rotational speed of the driving member 9. The clutch roller 14 rotates in the Y direction in FIG. 3, and the clutch roller 14 rotates in a direction opposite to the previous rotation, thereby applying a relative axial displacement to the members 9 and 11 to separate them from each other. As a result, the clutch roller 14 is released from being wedged between the 100-conical surfaces 8 and 10, and enters an idling state. Therefore, the turbine wheel 4
The transmission of the reverse load from to the pump wheel 2 takes place only hydrodynamically.

When the hydraulic pressure of the hydraulic cylinder 13 is released, the piston 12 receives the internal pressure of the torque converter T and retreats to its initial position, so that the direct coupling clutch Cd becomes inactive.

Referring again to FIG. 1, the mutually parallel persons of the auxiliary transmission M,
A first speed gear train G1, a second speed gear train G2, a third speed gear train G3, a fourth speed gear train G4, and a reverse gear train Gr are provided in parallel between the output shafts 3 and 16. The first speed gear train G1 includes a drive gear 17 connected to the input shaft 3 via a first speed clutch C1, and a one-way latch C that meshes with the gear 17 and connects to the output shaft 16.

and a driven gear 18 that can be connected via. The second speed gear train G2 consists of a driving gear 19 that can be connected to the input shaft 3 via a second speed clutch C2, and a driven gear 20 that is fixed to the output shaft 16 and meshes with the gear 19. The third speed gear train G3 consists of a driving gear 21 fixed to the input shaft 3, and a driven gear 22 connected to the output shaft 16 via a third speed clutch C3 and capable of meshing with the gear 21. Also the fourth
The speed gear train G4 is connected to the input shaft 3 via the fourth speed clutch C4.
A driven gear 24 is connected to the output shaft 16 via a switching gear Cs and meshes with the gear 23. Further, the reverse gear train Gr includes a driving gear 25 provided integrally with the driving gear 23 of the fourth speed gear train G4, a driven gear 26 connected to the output shaft 16 via the switching clutch Cs, and both gears 25. .26 and an idle gear 27 that meshes with the gear. The switching clutch Cs connects the driven gear 24 of the fourth speed gear train G4 and the idle gear 27.
By shifting the selector sleeve S of the clutch Cs to the forward position on the left or the reverse position on the right in FIG.
7 can be selectively coupled to the output shaft 16. One-way clutch CO transmits only drive torque from engine E to drive wheels w, w', and does not transmit torque in the opposite direction.

Thus, when the selector sleeve S is held in the forward position as shown in FIG. A gear train G1 is established, and torque is transmitted from the input shaft 3 to the output shaft 16 via this gear train G1. Next, the first
While the speed clutch C1 remains connected, the second speed clutch C2
When connected, the drive gear 19 is connected to the input shaft 3 to establish the second speed gear train G2, and torque is transmitted from the input shaft 3 to the output shaft 16 via this gear train G2. At this time, the first speed clutch C1 is also engaged, but due to the action of the one-way clutch CO, the first speed is not established, but the second speed gear train G2 is established, which is connected to the third and fourth speeds. The same goes for when. Release the second gear clutch C2 and apply the third gear clutch C3.
When the driven gear 22 is connected to the output shaft 16, the third speed gear train G3 is established, and when the third speed clutch C3 is released and the fourth speed clutch C4 is connected, the driven gear 22 is connected to the output shaft 16 and the third speed gear train G3 is established. 23 is connected to the input shaft 3 and the fourth speed gear train G4
is established. Furthermore, if the selector sleeve S of the switching clutch Cs is moved to the right in FIG. The reverse gear train Gr is established, and the output shaft 1 is connected from the input shaft 3 to the output shaft 1 via this gear train Gr.
Reverse torque is transmitted to 6.

The torque transmitted to the output shaft 16 is transmitted from the output gear 28 provided at the end of the shaft 16 to the large diameter gear DG of the differential device Df. One end of a speedometer cable 30 is fixed to the gear 29 meshing with the gear Ds fixed to the gear DG, and the speedometer 3 is connected to the other end of the speedometer cable 30 via a magnet 31a of a vehicle speed detector 31.
2 is connected, and the speedometer 32 is connected to the gear Ds, 29
and a cable 30 to display the vehicle speed.

The vehicle speed detector 31 includes the magnet 31a and a reed switch 31b, for example, which is driven by the magnet 31a.
1b is opened and closed, and on and off signals accompanying this opening and closing are supplied to an electronic control device 33, which will be described later.

FIG. 2 shows a hydraulic control circuit for a vehicle automatic transmission to which the present invention is applicable.

In the figure, a hydraulic pump P whose suction port is connected to an oil tank R is connected via an oil path 300 to an inlet port 60a of a regulator valve Vr, a pilot pressure introduction port 60b, and a port 70 of a manual shift valve (hereinafter simply referred to as a manual valve) Vm.
b and the inlet port 80a of the governor valve Vg, respectively. Ports 70a and 70c of manual valve Vm are connected to port 9 of servo piston 90 via oil passages 301 and 302, respectively.
0c.

90b, the port 70c is further connected to the port 70d of the manual valve Vm via the oil passage 303, the inlet port 270a of the pressure reducing valve 270, and the port 100a of the throttle valve Vt, and the port 70e is connected to the boat of the manual valve Vm via the oil passage 304. 70g1 is connected to the port 210d of the timing valve 210, the port 170a of the first accumulator 170, and the second speed clutch C2, respectively. In addition, the port 70r of the manual valve Vm is connected to the second shift valve ■2 via an oil passage 305 in which a throttle 350 and a one-way valve 380 are connected in parallel.
Port 130b and port 70h have aperture 359 in the middle.
and a one-way valve 383 are connected to the first speed clutch C1 via an oil passage 313 provided in parallel. Nucleus tract 313
Two inlet boats 400a and 400b of the flow rate regulating valve 400 are connected to the flow regulating valve 400 through an oil passage 307 provided with a throttle 369, and one outlet boat 400d of the flow regulating valve 400 is connected to the first outlet boat 400d via an oil passage 307a. shift valve v1 port) 12
Connected to 0b. A throttle 370 is interposed between the first inlet boat 400a of the flow rate regulating valve 400 and the oil passage 307.

Port 701 of manual valve Vm is connected to port 90a of servo piston 90 via oil passage 308, and port 70 is connected to port 21Oe of timing valve 210 via oil passage 309.
, the port 70m is connected to the port 190a of the second accumulator 190 and the fourth speed clutch C4, and the port 70m is connected to the port 70n of the manual valve Vm through the oil passage 310, and the second shift valve ■2
Bo 1-130d.

and the port 160b of the first control valve 160, respectively. Oil passage 310 and port 130 of second shift valve ■2
A throttle 356 and a one-way valve 381 are arranged in parallel with each other between the valve and the valve d.

Port t o o b of the throttle opening responsive valve Vt.

and 100C each port 170b of the first to third accumulators 170, 190, 180 via an oil path 311,
190b, 180b, port 2 of modulator valve 220
20f, port 230c of on-off valve 230, port 400c of flow rate adjustment valve 400, port 160a of first control valve 160, and port 200 of second control valve 200
a, respectively, and a throttle 352 is interposed between the port 100b of the throttle opening responsive valve Vt and the oil passage 311. The bow) 100d of the throttle opening response valve Vt is connected to the port 130g of the second shift valve v2 and the drain EX through an oil passage 312, and the oil passage 312 and the drain EX
A diaphragm 353 is interposed between the two. 1st 3rd control valve 1
10 ports 110. a is connected to the port 120a of the first shift valve 1 and the drain EX through an oil passage 315, and a throttle 35 is connected between the oil passage 315 and the drain EX.
4 is interposed.

Port 120c, 120 of first shift valve ■1
d are connected to the second shift valve ■ via oil passages 316 and 317, respectively.
The port 120e is connected to the port 160c of the first control valve 160 via the oil passage 318 to the ports 130a and 130c of the second control valve 160.
and a drain EX, and a throttle 355 is interposed between the oil passage 318 and the drain EX. The boat 130e of the second shift valve v2 is connected to the boat 200c of the second control valve 200 and the drain EX via an oil passage 319, and a throttle 357 is provided between the oil passage 319 and the drain EX.
is interposed. The port 130f of the second shift valve 2 is connected to the port 20 of the second control valve 200 via an oil passage 320 in which a throttle 358 and a one-way valve 382 are connected in parallel.
Qb, the boat 180a of the third accumulator 180, and the third speed clutch C3, respectively. Note that a throttle 356a is interposed in one of the two EX ports of the second shift valve v2.

The boat 120f of the first shift valve v1 is connected to the inlet boat 140a of the first solenoid valve 140 via an oil passage 340, and the oil passage 340 is connected to the outlet of the pressure reducing valve 270 via an oil passage 341 provided with a throttle 361. It is connected to boat 270b. The boat 130h of the second shift valve 2 is connected to the inlet port 150a of the second solenoid valve 150 via an oil passage 322a, and the oil passage 322a is connected to the oil passage 3 through a throttle 362.
22, and this oil passage 322 is connected to the outlet boat 80b of the governor valve 1g.

Each valve body 141. of the first and second solenoid valves 140.150.
151 is the deenergization (off) of solenoids 142 and 152, respectively.
At times, the spring force of the springs 143, 153 closes the inlet ports 140a, 150a, and the solenoid 14
When 2,152 is biased (on), the entrance boat 140a is attracted against the spring force.

150a is opened. That is, the first and second solenoid valves 14
0.150 is closed when the solenoid 142, 152 is deenergized and opened when it is energized.

The outlet port 60c of the regulator valve Vr is connected to the boat 210a of the timing valve 210 and the on-board via the oil passage 325.
They are connected to the boats 230d of the off valves 230, respectively. The boat 210b of the timing valve 210 has a throttle 371 in the middle.
The boat 210c is connected to the boat 220d of the modulator valve 220 via an oil path 321 provided with a
Of is connected to the oil passage 501 through an oil passage 501a provided with a throttle 375 in the middle. The boat 220b of the modulator valve 220 is an oil passage 3 in which a throttle 372 is provided in the middle.
26a to the oil line 326, and the ° port 220
C is connected to the boat 230b of the on-off valve 230 via an oil passage 353 provided with a throttle 373 in the middle, and boat 220e is connected to an oil passage 322 provided with a throttle 366a in the middle. The boat 230a of the on-off valve 230 is connected to the oil passage 326
, the boat 230e has an oil passage 5 with a throttle 374 in the middle.
It is connected to the oil passage 334 via 01.

The inlet boat 240a of the third solenoid valve 240 has a throttle 367
It is connected to the oil passage 326 via. This third solenoid valve 2
When the solenoid 242 is deenergized (off), the valve body 241 of 40 is pressed by the spring force of the spring 243 and opens the inlet bow)2.
40a is closed, and when the solenoid 242 is energized (on), it is attracted against the spring force and opens the inlet boat 240a. That is, the third solenoid valve 240 is closed when the solenoid 242 is deenergized, and opened when the solenoid 242 is energized.

The boat Ta of the torque converter T is connected to the oil passage 325 through the oil passage 334 provided with the throttle 368, the boat Tb is connected to the oil passage 326, and the boat Tc is connected to the pressure holding valve 2 through the oil passage 335.
50 inlet port 250a. This pressure holding valve 2
The pilot pressure introduction port 250b of No. 50 is connected to the upstream side of the throttle 366a of the oil path 322 via the oil path 336, and the outlet port 250c is connected to the drain EX via the oil path 337 and the oil cooler 260, respectively. Each drain EX is connected to an oil tank R, respectively.

Each solenoid 142, 152, 242 of the first to third solenoid valves 140.15Q, 240 is connected to a signal line 142a, 1
It is connected to the electronic control device 33 via 52a and 242a, respectively. The electronic control device 33 operates in accordance with a predetermined shift map based on input signals from a vehicle speed detector 31, an engine speed detector 34, a gear position detector 35, etc.
Then, the second solenoid valves 140 and 150 are controlled to control the engagement and disengagement (disengagement) of the first to fourth gear clutches C1 to C4, thereby controlling the speed change. Further, the electronic control device 33 actually measures a predetermined parameter value representing the relative slip amount of the output member of the torque converter T, for example, the speed ratio e, and compares the measured value e with a predetermined reference value, Based on the comparison result, the engagement force (transmission capacity N) of the direct coupling clutch Cd is determined and the third electromagnetic valve 240 is controlled to control the direct coupling clutch Cd.
control the engagement force of

The operation of the above-mentioned hydraulic circuit will be explained below.

The hydraulic pump P sucks and pressurizes the hydraulic oil in the oil tank R, regulates the pressure to a predetermined pressure (hereinafter referred to as line pressure PI) with the regulator valve Vr, and then pumps it to the oil path 300. The stator arm 5b (see Fig. 1) is in contact with the spring receiver 61 of the regulator valve Vr, and when the reaction force of the stator wheel 5 of the torque converter T reaches a predetermined value, the spring 62 is compressed and the hydraulic pump is activated. Increase the P discharge pressure. Such hydraulic control is detailed in Japanese Patent Publication No. 45-30861. A part of the hydraulic oil whose pressure is regulated by the regulator valve Vr is sent into the torque converter T through an inlet oil passage 334 having a throttle 368, and after pressurizing the inside thereof to prevent cavitation, the pressure holding valve 250, The oil is returned to tank R via cooler 260. In the pressure holding valve 250, as the vehicle speed U increases, the spool 251 moves to the right in the figure against the spring 252 due to the governor pressure Pc, and the internal pressure of the torque converter T is released to the oil tank R. In other words, the pressure holding valve 250 works to lower the internal pressure of the torque converter T in proportion to the vehicle speed U, and since its spool 251 is operated by the differential pressure with the governor pressure Pc, the transmission capacity of the direct coupling clutch Cd increases. The maximum transmission capacity of the direct coupling clutch Cd is increased on the side.

The manual valve ■m is switched by manually switching the shift lever, and is set to P (parking), R (reverse), N (neutral), D4 (4 forward automatic gears), D3, (3 automatic forward gears except TOP). It has six shift positions: Shift) and 2 (2ND hold), and an operating mode can be arbitrarily selected according to each shift position.

When the spool 71 of the manual valve Vm is in the illustrated N position, the port 70b connected to the oil passage 300 is blocked by the spool 71 of the manual valve Vm, and the other ports 70a, 70c-? On is all connected to the drain EX, and the four clutches 01 to C4 of 1st to 4th gears are all disengaged, so the engine torque is applied to the driving wheels W, W'' (see Figure 1). is not transmitted.

When the spool 71 of the manual valve Vm is shifted one frame to the left from the illustrated position and is at the D4 position, both the oil passages 302 and 313 communicate with the oil passage 300, and pressure oil is supplied to the oil passage 30.
5.304 communicate with each other. Also, the oil passage 309 communicates with the oil passage 310 or is isolated from the drain EX and the oil passage 308, respectively, and the oil passage 301 continues to communicate with the drain EX. As a result, at the D4 position (range), the servo piston 90 for moving the selector sleeve S (see Figure 1) receives the line pressure PR in its spring chamber 92, and the spool 91 also receives the line pressure PR (as shown in the figure). The selector sleeve S is held in the position shown in FIG. 1 by a shift fork 39 fixed to one end of the spool 91. As a result, the fourth speed driven gear 24 is switched to the switching clutch C.
In engagement with s, the reverse driven gear 26 is rotatably placed.

Even if the spool 71 of the manual valve Vm shifts one frame to the left from this state and is placed in the D3 position, the only difference is that the oil passage 310 is connected to the drain EX via the ports 70m and 70n. The connection relationship between the connected oil passages does not change. 2.1)], pressure oil is sent to the throttle opening response valve Vt via the oil passage 303 at position 044.

The throttle opening response valve Vt is a parameter representing the load of the engine E, and is proportional to the amount of depression of the throttle pedal (not shown), that is, the valve opening of the throttle valve (not shown) provided in the intake system of the engine E. The left spool 101 is moved to the left by receiving the displacement of the cam 104 which rotates counterclockwise from the illustrated position via the spring 103, and the port 10 is moved to the left.
0a to the open side, the discharge pressure of its output port LOOc,
Spool 1 in addition to port 1oOb via throttle 352
01 to the right to drive the port 100a to the closing side, and generates a pressure (hereinafter referred to as throttle pressure pt) in the output oil passage 311 that is proportional to the opening degree of the throttle valve. Also, the counterclockwise rotation of the cam 104 moves the right spool 102 to the left to connect the boat 100d and the drain E.
Continuously restricts the communication with
Alleviates the shift shock when kicking down to high speed (2ND).

Cam 113 of third control valve 110 interlocking with cam 104
rotates counterclockwise in accordance with the opening degree of the throttle valve to move the spool 111 to the left against the spring force of the spring 112, continuously restricting the communication between the boat 110a and the drain EX, and Alleviates the shift shock when kicking down from TOP to 3RD. Further, the throttle pressure pt is applied to the flow rate adjusting valve 400 via the oil passage 311.
40Qc and controls the valve 400. That is, when the flow rate adjustment valve 400 is in the state shown in the figure, the flow rate adjustment valve 400 passes only through the first inlet boat 400a provided with the throttle 370 from the oil passage 307, and from the outlet boat 400d through the oil passage 307a to the first shift valve 1. hydraulic pressure is sent to 120b,
Furthermore, when the throttle pressure Pt increases and overcomes the force of the spring 402, the spool 401 moves to the left and passes through both the first and second inlet ports 400a and 400b, thereby increasing the pressure from the outlet port 400d to the oil passage 307a. Increase the amount of oil supplied, and when the throttle valve opening is small, both clutches will engage (this will cause the two clutches to engage together, and energy will be consumed in both clutches, causing the vehicle speed to drop below the previous speed. In order to prevent this, the next clutch is not engaged until one clutch is completely disengaged, which reduces the shock of, for example, upshifting when the accelerator is released, or downshifting when stopping the vehicle. do.

The oil discharged from the hydraulic pump P is fed to the inlet boat 8Q of the governor valve Vg.
a, the governor valve Vg is rotated by its own shaft 82 at a speed proportional to the vehicle speed by a gear 81 meshing with the large-diameter gear DG shown in FIG. (hereinafter referred to as governor pressure PG).

When the first shift valve v1 is in the illustrated first position, the input oil passage 307a is connected to the output oil passage 316, and another output oil passage 317 is connected to the drain EX via the oil passage 318. The valve body 121 of the first shift valve v1 is shifted to the first position by the spring 122. The first shift valve v1 is caused to spring 122 by the hydraulic pressure reduced to a pressure lower than the line pressure PR introduced from the pressure reducing valve 270 through the oil passage 341, the throttle 361, and the oil passage 340 into the chamber 120A facing the right end surface. The output oil passage 316 can be moved to the left to take the second position against the spring force of the oil passage 315.
Another output oil passage 317 is separated from the oil passage 318 and connected to the input oil passage 307a.

When the first shift valve ■1 is in either the first or second position, the oil passage 313 is connected to the first speed (LOW') clutch C1, so that the manual valve Vm is in the D3 or When D4 is in position 1, the first speed clutch C1 is always pressurized and engaged. The spool 121 of the first shift valve v1 is controlled by a first solenoid valve 140, and when the solenoid valve 140 is closed, the pressure introduced into the chamber 120A causes the second position to be set to the second position, and when the solenoid valve 140 is opened, the spring 122 is moved to the second position. takes the first position.

When the second shift valve v2 is in the first position shown, it blocks the input oil passage 316, connects the output port 130d to the drain EX, connects the input oil passage 317 to the output oil passage 305,
Further, the output oil passage 320 is connected to the drain EX via the oil passage 312. The spool 131 of the second shift valve V2 has a spring 1
32 to the first position. This shift valve v2
is moved to the left against the spring force of the spring 132 by the governor pressure pa introduced from the boat 130h into the chamber 130A facing the right end surface of the spool 131 through the oil passage 322, the throttle 362, and the oil passage 322a, and is moved to the second position. and when in the second position, the output port 130d is connected to the drain E.
Separate it from X and connect it to the input oil path 316,
05 is connected to the drain EX via the oil passage 319, the remaining output oil passage 320 is separated from the oil passage 312, and the input oil passage 31 is connected to the drain EX through the oil passage 319.
Switch and connect to 7.

The spool 131 of this second shift valve v2 is controlled by a second solenoid valve 150, and when the solenoid valve 150 is closed, the second position is set by the governor pressure PG introduced into the chamber 130A, and when the solenoid valve 150 is opened, it is set to the second position by the spring spring. 132 to assume the first position.

Further, the second shift valve (2) is particularly provided with a click motion mechanism 133 so that its switching operation is performed in an on-off manner. This click motion mechanism 133
is the governor pressure Pc even when the second solenoid valve 150 is closed.
The spool position of the shift valve v2 is limited to either the first or second position in response to a change in the shift valve v2.

Now, as long as the engine E is rotating, the hydraulic oil pressurized by the hydraulic pump P is sent to the governor valve Vg.
g, the pressure is regulated as a signal pressure proportional to the vehicle speed U and guided to the chamber 130A of the second shift valve v2, and the pressure reducing valve 27
The pressure is reduced at 0 and guided to the chamber 120A of the first shift valve (1). To maintain these two shift valves v, , v2 in the first switching position shown when the manual valve Vm is in the D4 (or D3) position, the solenoids 142 and 152 of the two solenoid valves 140 and 150 are attached together. All you have to do is force the valve open. As a result, each clutch 02 to C4 of 2nd speed to 4th speed
is not pressurized, only the first speed clutch C1 is pressurized and engaged, and the first speed reduction ratio is established. Since this first speed generally covers a low speed region, the governor pressure PG itself is low pressure in this low speed region, and is discharged from the second solenoid valve 150 to the oil tank R via the throttle 362. The loss flow rate of the pressure oil caused by this process is correspondingly small, making it economical. At this point, like when starting from a stall (vehicle speed = 0), the pressure of the entire system is reduced to the normal pressure (line pressure P).
l) This is particularly advantageous if it has to be maintained significantly higher than 1).

Next, the solenoid 152 of the second solenoid valve 150 is energized to maintain the solenoid valve 150 in the open state, and the solenoid 142 of the first solenoid valve 140 is deenergized to keep the solenoid 150 open.
When the valve 0 is closed, hydraulic pressure reduced by the pressure reducing valve 270 is generated in the chamber 120A of the first shift valve v1, and this causes the spool 12 of the shift valve v1 to resist the spring force of the spring 122.
1 moves to the left. Due to this leftward movement of the spool 121, the oil path 3
07a is connected to the oil passage 305 through the oil passage 317, and when the oil passage 305 is in the D4 position, it is connected to the oil passage 304 through the port 70r of the manual valve Vm, the notch 71a of the spool 71, and the bow) 70g, and when it is in the D3 position. port 70 when
f, annular groove 71b of spool 71;

They are respectively connected to the oil passages 304 via the bow) 70e, and the second speed clutch C2 is engaged under pressure. Therefore, in the D4 or D3 position, the first gear clutch C1 and the second gear clutch C
2 are pressed into engagement. However, as shown in Figure 1, the first
Since a one-way clutch Co that transmits torque only in the direction of the driving torque from the engine E is interposed between the high speed driven gear 18 and the output shaft 16, a second speed reduction ratio is established.

Next, with the solenoid 142 of the first solenoid valve 140 deenergized and the solenoid valve 140 closed, the second solenoid valve 150 is opened.
When the solenoid 152 is deenergized and the solenoid valve 150 is closed, the governor pressure Pc at that time is generated in the chamber 130A of the second shift valve v2, and the resistance force by the spring 132 and the click motion mechanism 133 is reduced to the governor pressure. The spool 131 moves to the left and assumes the second position only when the left power by Pa increases. Due to this leftward movement of the spool 131, the oil passage 305 is connected to the drain EX via the oil passage 319, and the engagement of the second speed clutch C2 is released, and at the same time, the oil passage 320 is connected to the oil passage 317, which is a hydraulic pressure source. 3rd gear clutch C3
are engaged under pressure. At this time as well, the first gear clutch C1 is pressurized and engaged, but due to the action of the one-way clutch CO, the third gear clutch
A speed reduction ratio is established.

Next, the solenoid 152 of the second solenoid valve 150 is held in a de-energized state, and the solenoid 14 of the first solenoid valve 140 is held in a de-energized state.
2 is energized again to open the solenoid valve 140, the spool 121' of the first shift valve V1 moves to the right and returns to the position shown, connecting the oil passage 317 to the drain EX via the oil passage 318. , the engagement of the third speed clutch c3 is released, and at the same time, the oil passage 316 is connected to the hydraulic pressure source 307a, and the oil passage 310
Supply pressure oil to.

The oil passage 310 is connected to the oil passage 309 via ports 70m and 70k of the manual valve Vm when in the D4 shift position,
Fourth speed clutch C4 is engaged under pressure. At this time as well, the first speed clutch C1 is pressurized and engaged, but as described above, the reduction ratio of the fourth speed is established by the action of the one-way clutch Co. In this manner, automatic gear shifting from first to fourth gears is performed.

Each reduction ratio of these 1st speed to 4th speed and the 1st speed. The relationship between the second electromagnetic valves 140 and 150 and the respective solenoids 142 and 152 is shown in Table 1.

Table 1: On the other hand, the hydraulic pump P discharged from the regulator valve Vr
A part of the working oil pressure flows into the torque converter T through an oil passage 334 provided with a throttle 368 to increase its internal pressure and is sent to the timing valve 210 and the on-off valve 230. This timing valve 210 has chambers 210A and 210B introduced with oil pressure to be applied to a second speed clutch C2 and a fourth speed clutch C4, respectively, and a spool 211 has a second speed or fourth speed reduction ratio established. Sometimes the spring 212
The spring 212 moves to the left against the spring force of the spring 212 to reach the second switching position, and when the first or third speed reduction ratio is established.
The spool 212 is moved to the right by the spring force of
' takes the switching position.

When the timing valve 210 is in either of these two switching positions, it connects the input oil passage 325 to the output oil passage 327 and also connects the drain oil passage 32 of the modulator valve 220.
1 to the drain EX, but during the transition to the reswitching position, the output oil passage 327 is cut off from the input oil passage 325, and the drain oil passage 321 of the modulator valve 220 is cut off from the drain EX. The oil pressure in the output oil passage 327 of the timing valve 210 is input to the modulator valve 220, modulated, and output to its output oil passage 353. The modulator valve 220 modulates the hydraulic pressure using the governor pressure PG and the throttle pressure pt to create an engagement force for the direct coupling clutch Cd, and has oil passages 3 in the chambers 22OA and 220B, respectively.
Governor pressure PG, throttle pressure Pt via 22, 311
is introduced, and these two pressures and the spring force of the spring 222 move the spool 221 to the left toward the valve opening side, and the feedback pressure of the output oil passage 326 is applied to the oil passage 3j6a and the throttle 372.
The governor pressure Pc is received by the left end surface of the spool 221 via
, the spool 221 is moved to the right toward the valve closing side against the throttle pressure pt and the spring force of the spring 222. As a result, a pressure proportional to the vehicle speed U and the opening degree of the throttle valve appears in the output oil passage 353.

When the pressure output from the modulator valve 220 becomes too high, the spool 221 of the modulator valve 220 moves to the right in the figure against the resultant force of the governor pressure PG, throttle pressure pt, and spring 222 due to feedback pressure, causing the pressure to increase. is drained to drains F and X via the timing valve 210. When the gear is not being changed, the drain oil passage 32 of the modulator valve 220 is connected via the timing valve 210.
1 is always connected to the drain EX, and during the shift, the spool 211 of the timing valve 210 is moving, and the drain oil passage 321 is cut off from the drain EX, so that the pressure oil is not drained anywhere.

The reason for doing this is that it is necessary to control the engagement force (transmission capacity) of the direct coupling clutch Cd only by the third solenoid valve 240, and to prevent the engagement force of the direct coupling clutch CdO from decreasing excessively during gear shifting. be. In other words, when changing gears, the accumulator moves in connection with the gear shifting, which causes the line pressure PR to drop and the throttle pressure Pt to drop momentarily. For this reason, the spool 221 of the modulator valve 220 moves to the right in the figure, and when the drain oil passage 321 is connected to the drain EX at this time, the engagement force of the direct coupling clutch CdO itself decreases. Therefore, by interlocking with the timing valve 210 and blocking the drain oil passage 321 of the modulator valve 220 from the drain EX to prevent pressure oil from escaping anywhere, the engagement force of the direct coupling clutch Cd can be reduced during gear shifting. Deterioration can be prevented.

The pressure in the output oil passage 353 of the modulator valve 220 is
73, the oil is guided from the boat 230a of the on-off valve 230 to the cylinder 13 of the direct coupling clutch Cd in the torque converter T via the oil passage 326. Therefore, the engagement force (transmission capacity) of the direct coupling clutch CdO is strengthened according to the vehicle speed U and the opening degree of the throttle valve when the third solenoid valve 240 is closed. The on-off valve 230 receives the throttle pressure pt through the oil passage 311 in the chamber 230A, and at the throttle pressure pt, the spool 231 moves to the left in the figure against the spring force of the spring 232 to open the input oil passage 353. It is connected to the output oil passage 326, and when there is no throttle pressure Pt, that is, when the throttle valve opening is at the idle position, the spool 231 moves to the right by the spring force of the spring 232 and is held in the position shown in the figure, draining the oil passage 326. It connects to EX and also serves to connect oil passage 325 and oil passage 501. This on-off valve 230 is connected to the direct clutch Cd when the valve opening of the throttle valve is at the idle position.
This is to release the engagement. At this idle position, the oil passage 325 and the oil passage 501 are connected, so that the amount of oil flowing into the torque converter T from the inlet boat Ta of the torque converter T increases, and the pressure inside the torque converter T increases. Since the piston 13 is pushed to the left in the figure, it is in the idle position (when the accelerator pedal is released)
The disengagement of the direct coupling clutch Cd can be reliably performed.

The third solenoid valve 240 controls opening and closing between the oil passage 326 and the drain EX to control the operating pressure of the direct coupling clutch Cd or the pressure of the piston 13, thereby controlling the engagement force of the clutch Cd. and this third solenoid valve 24
When the solenoid 242 of 0 is energized and opened, the throttle 3
73, the oil pressure in the oil passage 326 decreases, and the direct coupling clutch C
The dO engagement force (transmission capacity) is weakened.

The solenoid 242 of this third solenoid valve 240 determines the relative actual speed ratio e between the torque converter T and the output member.
The electronic control unit 33 that measures the speed ratio e is controlled so that the speed ratio e falls within a reference range value, as will be described later. When the solenoid 242 of the third solenoid valve 240 is deenergized and the solenoid valve 240 is closed, the modulator valve 242 is closed.
The output of 0 itself becomes the engagement force of the direct coupling clutch Cd,
The output acts on the hydraulic cylinder 13 via the on-off valve 230 and the oil passage 326, and the operating pressure increases in proportion to the vehicle speed U, as shown by the solid line I in FIG. In FIG. 4, the influence of the throttle pressure Pt is omitted for the sake of simplicity.
This is what happens when 22 is omitted.

On the other hand, in the 4y state in which the solenoid 242 of the third solenoid valve 240 is energized and the solenoid valve 240 is opened, the hydraulic cylinder 13 controls the oil passage 326, the throttle 367, and the third solenoid valve 240. Since it is opened to the drain EX through the drain EX and the pressure decreases, the engagement force of the direct coupling clutch CdO becomes weak or zero, and its operating pressure has the characteristics shown by the broken line (■) in FIG.

Therefore, by controlling the duty ratio of the opening time of the third solenoid valve 240, the operating pressure of the direct coupling clutch Cd can be adjusted to the fourth solenoid valve 240.
The distance between the solid line ■ and the broken line ■ in the figure can be created arbitrarily.

In this example, between the solid line ■ and the broken line ■ in FIG.
The duty ratio is controlled in 21 stages from θ to 20J, of which the representative one shown in Fig. 4 is on-duty ratio (hereinafter simply referred to as duty ratio) of 60%.
The working pressure when the duty ratio is 30% is shown by the solid line (■), and the solid line (■) is the working pressure when the duty ratio is 30%. In Figure 4, the chain line ■
The straight line shown by indicates the internal pressure P of the torque converter T, and the differential pressure between the working pressure shown by the solid line 1 to m or the broken line ■ and the internal pressure PT determines the strength of the engagement force of the direct coupling clutch Cd. do.

(Operation) FIGS. 5 to 7 are flow charts showing the method of the present invention,
The operation of the method of the present invention will be explained below along with this flowchart.

In FIG. 5, when the ignition switch is first turned on, the CPU of the electronic control unit 33 is initialized (
Step 1): All variables related to transmission capacity control of the direct coupling clutch Cd are set to initial values. Next step 2
Proceed to the vehicle speed detector 31, engine rotation speed detector 34,
Each input data from the gear position detector 35 etc. is read, and in step 3, the time intervals of the vehicle speed pulse signal and the engine rotation speed pulse signal respectively inputted are measured to determine the vehicle speed U,
The engine speed Ne is calculated, and the torque converter T (described later) is operated based on the vehicle speed U and the engine speed Ne.
The speed ratio e between the pump wheel 2 and the turbine wheel 4 (see FIGS. 1 and 2) is calculated (step 4).

This value e is calculated as follows.

When the turbine wheel rotation speed is N2, the speed ratio e of the torque converter T is expressed by the following equation.

- Since it is connected to the cable pulley 30 via a gear train, there is no slippage between them.If the reduction ratio between them is A and the rotation speed of the speedometer cable 30 is N3, then Rotation speed N2 of torque converter output shaft 3
is, N2=A-Nz...(2)
becomes. When formula (1) is rearranged using formula (2), the speed ratio e is expressed by the following formula.

In this case, the value of the reduction ratio A may take values A1 to A4 corresponding to each of the detected speeds, that is, the reduction ratios of the first to fourth speeds.

Note that a rotation speed detector may be attached to the input shaft 3 of the auxiliary transmission M in order to determine the output side rotation speed of the torque converter T.

After calculating the speed ratio value e in step 4, the process proceeds to step 5, whereupon a routine for controlling the direct coupling clutch Cd (Cd, C0NTR0L) shown in FIG. 6 is executed.

In FIG. 6, first, in step 1, the engine speed Ne
is larger than a predetermined rotation speed Ne3 (for example, 3.500 rpm), and if the answer is affirmative (Yes), proceed to step 16 and turn off the third solenoid valve 240, that is, close it and directly connect it. The hydraulic pressure of the clutch Cd is increased to strengthen the mooring force of the direct coupling clutch CdO.

This means that if the engine speed Ne is 3.50 rpm or higher, there is no risk of problems such as vibration, and the direct coupling clutch C
By increasing the engagement force of d, clutch slippage is suppressed,
It is possible to improve the life span and fuel efficiency of the direct coupling clutch Cd. At this time, the working oil pressure supplied to the direct coupling clutch Cd is maintained on the solid line ■ in FIG. 4.

If the answer to step 1 is negative (No), it is determined in step 2 whether or not the gear position of the auxiliary transmission M is the fourth speed, and if the answer is affirmative (Yes), step 6 is performed. If the answer is NO, the process proceeds to step 3, where it is determined whether the gear position is the third gear.

If the answer to Step 3 is affirmative (Yes), that is, if the gear position is the third gear, then Step 5 is answered (No).
In each case, proceed to step 4.

As a result of the determination in steps 2 and 3, when the vehicle is in fourth gear, the upper limit vehicle speed U32 is changed to the predetermined vehicle speed U432 in step 6.
(for example, 85 km/h), when the vehicle is in third gear, the upper limit vehicle speed U32 is set to the designated vehicle speed U332 (for example, 40 km/h) in step 5, and when the vehicle is in second gear or lower, the upper limit vehicle speed U32 is set to the designated vehicle speed U232 (for example, 30 km/h) in step 4.
km/h). In this way, the upper limit vehicle speed U32 is set to U232. [J332. and U432
After setting the vehicle speed to one of the vehicle speeds, the process proceeds to step 7, where it is determined whether the vehicle speed U is greater than the upper limit vehicle speed U32 set in any of steps 4 to 6, and the answer is affirmative (Yes). ), problems such as vibration will not occur, and the process proceeds to step 16, where the third solenoid valve 240 is closed and the engagement force of the direct coupling clutch Cd is strengthened.

If the answer to step 7 is negative (No), that is, if the vehicle speed U is smaller than the upper limit vehicle speed U32, the process proceeds to step 8 where the vehicle speed U is determined to be the lower limit vehicle speed U31 (for example, 6 km/h).
Determine whether the value is greater than or not. The answer is negative (No),
That is, if the vehicle speed U is lower than the lower limit vehicle speed U3+ and is in a low vehicle speed range that requires the torque amplification function of the torque converter T, the steering knob 18 is operated and the third solenoid valve 240 is activated.
By turning on, that is, opening the valve, the direct coupling clutch Cd
The function of the torque converter T is utilized by lowering the operating pressure of the direct coupling clutch Cd and weakening the engagement force of the direct coupling clutch Cd. The working oil pressure supplied to the direct coupling clutch Cd at this time is indicated by the broken line Iv in FIG.
change upwards. If the answer to step 8 is affirmative (Yes), that is, if the vehicle speed U is higher than the lower limit vehicle speed U31, the process proceeds to Stellaf 9, and it is determined whether or not the gear position of the auxiliary transmission M is the fourth gear. do. If the answer to this step 9 is affirmative (Yes), in step 10 the vehicle speed U
is greater than a predetermined vehicle speed U3G (for example, 58 km/h), and if the answer is affirmative (Yes), that is, if the gear position is 4th gear and the vehicle speed U is greater than the predetermined vehicle speed U3e. , in step 12, the determination values e1 (for example, 92%), C2 (for example, 97%), 63 (for example, 99.5%), and ea (for example, 102%) in a predetermined speed ratio range are set, respectively. The discrimination value e1 is an upper limit value of a region where the engagement force of the direct coupling clutch Cd is weak (hereinafter referred to as a weak engagement force region) and a lower limit value of a region approximated to a reference value (hereinafter referred to as a reference value approximation region). The discrimination value e2 is the upper limit value of the reference value approximation region and the lower limit value of the reference value region (target region). The discrimination value e3 is the upper limit value of the reference value region and the lower limit value of the fine adjustment region. The discrimination value e4 is the upper limit value of the fine adjustment region and the lower limit value of the region where the solenoid is turned on to open the third electromagnetic valve 240' (hereinafter referred to as the solenoid on region). If the answer to step IO is negative (NO), that is, if the gear position is the 4th gear and the vehicle speed U is smaller than the predetermined vehicle speed Um, the determination value e1 (e.g. 88%), C
2 (e.g. 94%), e-ri (e.g. 97.5%), e
< (for example, 99%).

If the answer to step 9 is negative (NO), that is, if the gear position is not the fourth gear, the process proceeds to step 11, where it is determined whether the gear position is the third gear. If the answer to step 11 is affirmative (Yes), that is, if the third speed
8%), C2 (e.g. 94%), e+ (e.g. 97.5
%), e, and g (for example, 99%).

If the answer to step 11 is negative (No), that is, if the gear position is neither 4th speed nor 3rd speed, the process moves to step 15 and the discrimination values e1 (e.g. 88%), 1
1!2 (e.g. 94%), C3 (e.g. 97.5%),
ea (for example, 99%) is set respectively.

After setting the respective discrimination values e1 to e4 in steps 12 to 15, the process proceeds to step 17, where the duty ratio control of the solenoid valve 240 (solenoid valve DUTY C) shown in FIG.
0NTR0L) routine.

Step 1 in FIG. 2. 3. In steps 7 and 7, it is determined in which region of the speed ratio range the current speed ratio e falls. First, considering that the speed ratio e changes from the bottom to the top, if the speed ratio e is in the weak engagement force region, it is difficult to determine whether the speed ratio e is larger than the discrimination value e1 in step 7. The answer is negative (No) and step 8
It is determined whether the timer period T1 has elapsed (T=O).

FIG. 8 shows the duty ratio control situation when the speed ratio e passes from the weak engagement force region to the standard value approximation region of 1 and enters the upper reference value region, which is clear in this figure. As the speed ratio e approaches the reference value region, the rate of increase in the transmission capacity of the direct coupling clutch Cd is reduced, that is,
The rate of change in transfer capacitance is controlled to be small.

When the speed ratio e is in the weak engagement force region, T1 (for example, 0
．． Every time a period of
By controlling the duty ratio of the zero valve opening time, the engagement force of the direct clutch CdO is gradually strengthened. In FIG. 7, if the answer to step 8 is affirmative (Yes), that is, when the timer period (T1) has elapsed (tl in FIG.
.

t2. and time t3) Each time, in step 9, the timer is set to the value T1, and in step 10, the variable value is set to a value (D-x+) smaller than the previous value by xl, and this is stored. The duty ratio control of the opening time of the third electromagnetic valve 240 (steps 8 to 13) is repeated again over the T1 period at the duty ratio at the stage indicated by the value. Note that step 11 is a limit check, and if the variable value is smaller than 0, problems will occur in program control, so it is determined whether the variable value is larger than the minimum 1) + 1im (for example, 0), and the If the answer is negative (NO) and the partial variable value is smaller than O, the value of the variable value is set to the minimum value D41im in step 12, and step 1
Move on to 3. If the answer to step 11 is affirmative (Yes), that is, if the variable value is greater than O, step 1
Skip step 2 and proceed to step 13.

In step 13, the value of the variable set in step 10 is stored as a variable D32 for later use in control when the speed ratio C enters the reference value range. After this, in step 14, the solenoid 2 of the third solenoid valve 240 is
The counter that controls the energization time to 42 is set to a value corresponding to the variable value, and then the process returns to SHEET/KNOB 2 in FIG. 5 and is executed again. Note that the electronic control device 33 operates the third solenoid valve 2 at the same duty ratio, that is, at a constant cycle, until the duty ratio of the third solenoid valve 240 is set to a new value.
Repeat 40 valve openings. Here, the duty ratio of the third solenoid valve 240 refers to the ratio of the energization time to the solenoid 242 to a predetermined time (for example, 100 m5), and +D
When set to 21 stages of O'''D20, the energization time per stage is 5 ms.

In this way, when the speed ratio e is in the weak engagement force region, the engagement force of the direct coupling clutch CdO is gradually strengthened toward x1 every period T1.

Next, when the speed ratio e enters the reference value approximation region (at time t4 in FIG. 8), the answer to step 7 becomes affirmative (Yes),
In step 15, it is determined whether the timer period has elapsed.

The timer period here means that when the speed ratio e is in the weak engagement force region just before entering the reference value approximation region, the timer is struck, and t3 in FIG.
This is the value T1 set at the time. As soon as the answer to step 15 is negative (No).

In other words, steps 16 to 1 are performed until the timer period T1 has elapsed.
Steps 13 and 14 are executed without executing step 9, and the third solenoid valve 240 is subsequently controlled to the opening side using the duty ratio set in the weak engagement force region. If the answer to step 15 is affirmative (Yes), that is, the timer period T
1 has passed (time 5 in Figure 8), step 16
Set the timer to a predetermined value T2 (for example, 1 second) that is larger than the T1 value set in the weak engagement force region, and in step 17 set the variable value to a value (D- X2) is set and stored, and the duty ratio control of the opening time of the third electromagnetic valve 240 is performed again over the T2 period at the duty ratio at the stage indicated by the D value. Then, when the timer period T2 has elapsed again and the speed ratio e value is still in the reference value approximation region, t6 in FIG.
), steps 15 to 19, and 13 as above
Execute repeatedly. Note that step 18 is step 1.
This is a limit check similar to 1, and the variable value D−h<
It is determined whether or not it is larger than the minimum value D21im (for example, 0), and if the answer is negative (No), that is, when the variable value is smaller than 0, the value of the variable is set to the minimum value D2 in the sub-tool 19.
Set it to 1im and move on to step 13.

; If the answer to step 18 is affirmative (Yes), that is, if the variable value is greater than O, the process moves to step 13 without executing step 19.

When the speed ratio e enters the reference value region at time t7 in FIG.
The flag F1, which performs f&t at 0, is set to 0, and the process proceeds to step 21, where it is determined whether 1 is set in the flag F3, which will also be described later.

When the speed ratio e enters the reference value region from a smaller value, flags F2 and F3 are both set to O (steps 5 and 6), and the answer to step 21 is negative (No).
), and the answer to the question of whether flag F2 is set to 1 in the next step 24 is also negative (No).
In this case, the process moves to step 26 and it is determined whether or not the timer period has elapsed. The timer period here is the value T2 set when the speed ratio e is in the reference value approximation region, that is, at time t6 in FIG. The answer to step 26 is negative (No
), steps 27 and 28 are not executed until the timer period T2 has elapsed, and steps 41 to 4, which will be described later, are executed.
Step 6 is followed by step 14, and the third solenoid valve 240 is subsequently controlled to open at the duty ratio set in the reference value approximation region.

If the answer to step 25 is affirmative (Yes), that is,
When the timer period T2 has elapsed (at time t8 in FIG. 8),
Once again, in step 27, the timer is set to a unique value when the speed ratio e is in the reference value region, T3 (for example, 2 seconds), and in step 2B, in the previous loop, in step 13, the variable value 1) is set. The value stored as 32, i.e.
The value set when the speed ratio e is in the reference value approximation region immediately before entering the reference value region (time t6 in FIG. 8) is set as is. In this way, when the speed ratio e enters the reference value area, the timer period T3 elapses using the value set immediately before entering the reference value area (time 6 in Figure 8) without rewriting the value of the variable . The valve opening time of the third electromagnetic valve 240 is duty-controlled until (time t9 in FIG. 8). (Even after time 9, the transmission capacity of the direct coupling clutch Cd is controlled not to be changed as long as the speed ratio e is within the base ?% value range.

FIG. 9 shows a duty ratio control state using a method different from that in FIG. 8 in duty ratio control when the speed ratio e enters the reference value region from the weak engagement force region through the reference value approximation region as in FIG. 8. . That is, in the case of FIG. 8, xl and x2
By keeping the same value and making the values of T+, T2, and T3 different, the rate of change over time of the speed ratio e becomes smaller as the speed ratio e approaches the reference value region. In this case, the values of T+, T2, and T3 are all the same, and the values of xl and x2 are different, so that the rate of change over time of the speed ratio e becomes smaller as the speed ratio e approaches the reference value region. be.

Figure 1O shows the duty ratio control state when the speed ratio e exceeds the reference value region, enters the fine adjustment region above the reference value region, and returns to the reference value region again without exceeding the fine adjustment region. shows. In this case, if the speed ratio e enters the reference value range from below, the values of all flags F+, F2, and F3 are O. Therefore, the speed ratio e increases from time t10 in (a) of FIG.
When the speed ratio e exceeds the reference value region and enters the fine adjustment region directly above it at time point 11, the answer to the determination as to whether or not the speed ratio e is greater than the discrimination value e3 in step 2 of FIG. 7 is affirmative (Yes).
Therefore, the process moves to step 29, sets the flag F1 to 1, and then proceeds to step 30. The step 30 includes
It is determined whether knob F2 is 0 or not, but since this flag F2 is still set to O, the answer to the determination is affirmative (Yes), and the process moves to step 31, where flag F2 is set to 1. do.

Next, in step 32, the variable D-C is set as the variable value D33.
Store the value of . This D32 value is the D value used when the speed ratio e is within the reference value region, that is, the D value used in step 28.
This is the same as the D value set in . In addition, there are variables in Figure 10, and various time changes of D32 and D33 are the speed ratio e.
This is shown along with the change in . In this case, for various variables such as variables, only the increase/decrease values thereof are shown based on the value set when the speed ratio e value is in the reference value region. Next, in step 33, the timer is set to a predetermined value T4 (for example, 0.4 seconds), and in step 34, the variable value used for the current control is set, and D33 used for the previous control is set to X6 (for example, 6).
After setting the added value, steps 41 to 4 described later
6 and 14, return to step 2 in FIG. 5 and re-execute.

What should be noted here is that when the speed ratio e is in the reference value region immediately before entering the tI'& adjustment region, that is, the 10th
The timer period T- set at time t10 in (al) in the figure
1 does not time up until t″1111, but
At the time t11 when the speed ratio e reaches the SEI-specific value e3, that is, the lower limit value of the fine adjustment region, the timer is immediately reset to the value T4 (step 33), and the timer is set in step 34 until the T4 period has elapsed. The control is repeated with the value of D. When step 30 is reached through such repetition, since the flag F2 was set to 1 in step 31 in the previous loop, the answer to step 30 is negative (NO) and the process moves to step 35, and the timer period T4 is still timed out. Therefore, the answer to the determination as to whether or not the timer period has elapsed in step 35 is negative (No), and in step 36, X3 (for example, l) is added to the D33 value set in step 32 as the variable value D32. Store the added value. In step 32 in the previous loop, the value D3 is set as the variable value D33.
2 is set, so if the value set when the speed ratio e is in the reference value area is set as DO, the value newly stored as the D32 value is this value.

It is equal to the value obtained by adding x3 to

Before the speed ratio e passes the timer period T4, that is,
If it returns to the reference value area again at time ti2, the answer in step 3 will be affirmative (Yes), and the process will proceed to step 20, where the flag F1 will be set to 0. In the next step 21, in this case, the flag F3 will be set to 0. Since it is still set to , the process skips over this and moves to step 24. Since flag F2 was set to 1 in step 31, the answer to step 24 is affirmative (Yes), and the process moves to step 25 to set flag F2.
is set to O, skipping step 26 and proceeding to step 27, where the predetermined value T3 is set in the timer. That is, skipping step 26 and proceeding to step 27 means that the timer is reset as soon as the speed ratio e returns to the reference value range.

Next, in step 28, the value D32 stored in step 36 in the previous loop is set as a variable value, and the duty ratio of the opening time of the third solenoid valve 240 is controlled at the duty ratio of the stage indicated by the value of D32.

Then, even at time t13 when the speed ratio e has passed the timer period T3, as long as it is within the reference value range, the T3 value is set in the timer again (step 27), and the D value remains unchanged even after the time 1+<. Same value D32 (step 2
8) controls the duty ratio.

+R in Figure 10), the speed ratio e exceeds the reference value region and enters the fine adjustment region for a short period of time (period shorter than the timer period T4)
This is the case when only one person enters. That is, since the speed ratio e has entered the fine adjustment region, at time t11, as a result of applying a large value of x6, the timer period T4 does not elapse.
The fact that it immediately returned to the standard value area at +2 point means x6
Therefore, at time t12 when the value returns to the reference value area, the value obtained by adding a small correction value x3 to the variable D4rX set at time tjo, in the reference value area immediately before exceeding the reference value area, is By controlling the duty ratio using , the speed ratio e is maintained within the reference value range.

In the case of (bl in Figure 10), the speed ratio e increased from time t15 and exceeded the reference value region and entered the fine adjustment region, so correction was applied with a large value x6 at time t+6. , it does not immediately return to the reference value area but stays in the fine adjustment area for a long time.
This is a case where the timer remains (for a time longer than the timer period T4). In this case, just before exceeding the reference value area and entering the fine adjustment area, that is, the time period during which the speed ratio e value remains in the fine adjustment area is added to the value obtained by adding the xc value to the D value set at time t+q. The speed ratio e is maintained in the reference value region by controlling the duty ratio using a value added according to the speed ratio.

Therefore, in the case of (bl in FIG. 10, steps 29 to 34 are respectively executed at the time of tus as in the case of (al at L11 in FIG. 1θ), and from time t'6 to tl-1
Until that point is reached, steps 29, 30, 35 and 36 are executed respectively. Then, when the time tl-1 is reached, the timer period T4 times up for the first time, so the answer to step 35 becomes affirmative (Yes), and the process moves to step 37, where the flag F3 is set to 1, and then,
In step 38, the value used in the previous loop is stored in D33 as a variable value. Then, in step 39, the timer is set to the T4 value again, and in step 40, the value xq is set to the D value.
Set the value by adding (for example, 1). Then, steps 29, 30, 35 and 36 are executed again until the timer period T4 times up at the time Ne, and in step 36, a value obtained by adding the above value x 3 to the D33 value is stored as the D32 value. If the speed ratio e is still in the fine adjustment region at the time, step 37.38 is performed as before.
Execute each. The execution of steps 37 and 38 means that the t)+3 value is updated to the value obtained by adding the value x3, and in step 40, the value x is further added to the D value, so that the duty is again The value increases and duty ratio control is repeated with this value. Then, at time t19, when the speed ratio e returns to the reference value region, steps 20 and 21
Execute. The answer to step 21 is the answer to step 37.
Since flag F3 is set to 1 in step 22, the result is affirmative (Yes), flag F3 is set to O in step 22, and step 2
At step 3, the flag F2 is set to 0, and step 24 is skipped and the process proceeds to step 26, where it is determined whether or not the timer period T4 has timed out. Skipping step 24, ie, not determining flag F2, means that the speed ratio e is changing slowly. If the speed ratio e is changing slowly, the duty value set in the previous loop is used as is. That is, it waits until the timer period T4 has elapsed, that is, until the time t'19 is reached, and the duty value set in the previous loop is used as is to control the duty.When the time t'19 is reached, the answer of step 26 is If the result is affirmative (Yes), the timer is set to the T3 value in step 27, and step 2
At 8, the value of the variable is D-! Set 2. This D32 value is the value set immediately before the fine adjustment area set in step 36 is extracted.

In this way, when the speed ratio e returns to the reference value region, duty ratio control is continued based on the variable value, and as long as the speed ratio e remains within the reference value region, the value is maintained after time t20 and the duty ratio is maintained. Control the ratio.

FIG. 11 shows the control state when the speed ratio e goes from the reference value region to the fine adjustment region, enters the solenoid ON region, and then returns to the reference value region again.

Note that FIG. 11 shows a state in which the speed ratio e is in a range larger than the discrimination value e4, that is, in the solenoid ON region.

FIG. 11(a) shows the case where the speed ratio e passes through the fine adjustment region in a short time and enters the region where the solenoid is turned on.
In Fig. 11, (bl) indicates the case where the speed ratio e passes through the fine adjustment region for a long time and enters the region where the solenoid is turned on.In both cases of (a) and (b) in Fig. 11, Since the speed ratio e approaches the upper limit of 1.0 (en), there is a risk of vehicle body vibration, so the duty ratio is the highest, D20.
(The solenoid 242 of the third solenoid valve 240 is turned on and the solenoid valve 240 is opened.) However, when the speed ratio e returns from the solenoid on region to the fine adjustment region again, the duty value is In FIG. 11, (a) is set to a larger value than (b).

That is, in (a) of FIG. 11, when the speed ratio e increases from the time tzg and enters the fine adjustment region at the time t''10, the answer to step 2 in FIG. Steps 29 to 34 are executed in the same manner as explained in the figure. At this time, the D value and the D33 value are +x6 (for example, 4) and +0, respectively, with respect to the previous value.

And in the next loop steps 29.30.35 and 36
are executed respectively, and in step 36, the DJU value is set to the value X3.
The value obtained by adding (for example, 1) is stored as the D32 value. At this time, flag F3 remains at 0. In this state, if the speed ratio e exceeds the fine adjustment region before the timer period T4 elapses (at time t31), the answer to the determination as to whether or not the speed ratio e in step 1 of FIG. 7 is greater than the discriminant value e4 is The result is affirmative (Yes), and the process moves to step 47 where flag F is set.
2 is set to 1, and in step 48 it is determined whether the flag F3 is set to 1. As mentioned above, flag F
3 remains at 0 and the speed ratio e leaves the fine adjustment region and enters the solenoid on region, so the answer to step 48 is negative (No.
), the process moves to step 50 and the value X5 is added to the D33 value.
(For example, 6) is added and the value is stored as the D value. Next, in step 51, it is determined (limit check) whether the D value is larger than the DFO value (=20). If the answer is affirmative (Yes), the D value is set to the value DFO in step 52 and the process moves to step 53. If the answer is negative (No), step 52 is skipped and the process moves to step 53. In step 53, the D value (for example, +6) set in step 51 is stored as a 032 value, the timer is set to 0 in step 54, and the solenoid 2 of the third solenoid valve 240 is set in step 55.
42 is turned on to maintain the solenoid valve 240 in the open state, while at step 56 the electronic control unit 33 stops the valve opening duty ratio control of the third solenoid valve 240, and the fifth solenoid valve 240 is turned on again.
Return to step 2 in the diagram.

Then, when the speed ratio e enters the fine adjustment 't4 region again at time t32 in (a) of FIG. 11, the answer to step 2 of FIG. Since the flag F2 was set to 1 in step 47 of the previous loop, the answer to step 30 is negative (No), and the process moves to step 35.

The answer to step 35 is affirmative (Yes) because the timer was set to O in step 54 of the previous loop.
In step 37, the flag F3 is set to 1, and in the next step 38, the D value (+X5, ie, +6) is stored as the D33 value. Then, in step 39, the timer is set to the predetermined value T.
4, and in step 40 the value of D+x3 (i.e. +5+
l=+7) as a new value, and in step 36 of the next loop, the value of D31+x3 (i.e. +5+l=+7)
is stored as a 032 value.

Thereafter, at time t33, the speed ratio e continues to enter the fine adjustment region, so steps 29, 30°35.3
Execute steps 7 to 40, respectively. D value (+7) in step 38
is stored as a D33 value, and in step 40, the value of D+x3 (+8) is stored as a D value. Then, the answer to step 35 becomes negative (No) again, and the process moves to step 36.
The value of D33+x3 (+8) is stored as the D32 value.

Next, when the speed ratio e enters the reference value region at the time t°33, it is controlled by the same effect as at the time ti9 to L°19 in FIG. speed ratio e
As long as D is within the reference value range, the duty ratio is controlled without changing the D value.

In the case of (bl in FIG. 11), when the speed ratio e enters the fine adjustment region at the +35 point, steps 29 to 34 in FIG. 7 are respectively executed in the same way as at the +30 point in FIG. In step 32, D (i.e., +0; in step 34, D33+x
6 (+4) is stored as the D value, and in the next step 36, D33+X3 (+1) is stored as the D32 value. Since the speed ratio e continues to be in the fine adjustment region at +36 after the T4 period has elapsed, steps 29, 30.
35 and 37 respectively, and in the next step 38 the D value (
+4) is stored as the Dη value, steps 39 and 40 are executed, and the value of D+x3 (+5) is stored as the D value in step 40.

And +3-? At this point, when the speed ratio e leaves the fine adjustment region and enters the solenoid ON region, the answer to step 1 in FIG. 7 becomes affirmative (Yes), and steps 47 and 48 are executed, respectively. In this case, from the time when the speed ratio e is +35, the first T, ll! +3 in the middle of the next Ta period after IJI period elapses
Until the 7th point, we were in the fine adjustment area,
The change state of the speed ratio e is gradual, and the flag F3 is 1.
is set. Therefore, the answer to step 48 is affirmative (Yes), and the process moves to step 49 where D33+X
The value of 4, that is, +5, is set as the D value, and then step 52 is executed. If the answer is affirmative (Yes), the process moves to step 53; if the answer is negative (NO), step 52 is skipped and step 53 is executed. Move to. In step 53, the D value set in step 49, ie, +5, is stored as the D32 value, and thereafter steps 53 to 56 are executed, respectively, and the process returns to step 2 in FIG. 5 to be executed again.

Then, when the speed ratio e enters the fine adjustment region again at the +36 point, steps 29, 30, 35 and 37 are executed, and the D value (D33+X4=+5) is changed to D33 in the next step 38.
Store as a value. Then, in step 40, the D value is set to D3.
The value 3+X3=+6 is stored as the D32 value.

After that, T! If the speed ratio e enters the reference value region at time t 39, when one period has not elapsed, t in (a) of FIG.
Controlled by the same effect as at time 12 to t+q, t 4Q
The time point reaches +41, and thereafter, as long as the speed ratio e is within the reference value range, the duty ratio is controlled without changing the value of D.

Note that F1=1 in step 4 in FIG. 7 means that the speed ratio e once enters the fine adjustment region from the reference value region, and the speed ratio e in the next loop passes through the reference value region and changes to the lower coefficient. When entering the weak resultant force region, that is, when the speed ratio e changes rapidly, flag F1 is set to 1, which means that control should be performed using the D value set in the previous fine adjustment region.1 In addition, steps 41 to 46 are limit checks, and various types of D32 and D33 are DFO values (for example, 20
If the value is greater than 1, each of these values is rewritten to a value DFO.

In addition, although the above embodiment describes the case where a fluid torque converter T is employed as the fluid power transmission device, the present invention can be applied to any automatic transmission for a vehicle equipped with other types of fluid couplings, etc. It is.

Further, the predetermined parameter representing the relative slippage amount of the human body and the output member of the fluid power transmission device may be the difference between the respective rotational speeds of the human body and the output member.

(Effects of the Invention) As described in detail above, the direct coupling mechanism control method of a hydraulic power transmission device of an automatic transmission for a vehicle according to the present invention provides a predetermined amount of slippage between the output member and the output member of the fluid power transmission device. The measured value of the parameter value is compared with a predetermined reference range value set in advance, and the transmission capacity of the direct coupling mechanism for the predetermined period to be implemented is determined based on the comparison result. A fine adjustment area for finely adjusting the transmission capacity to the decreasing side when the value is above the reference range value is set in contact with the upper side of the predetermined reference range value.

Therefore, even if the transmission capacity of the direct coupling mechanism is set precisely, the transmission capacity can be stably and quickly controlled to the reference value (target value) range without causing divergence, and the generation of vehicle body vibration and noise is suppressed. At the same time, the fuel efficiency and power transmission characteristics are improved, and an extremely smooth and comfortable driving feeling can be obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an automatic transmission for a vehicle to which the direct coupling mechanism control method of the present invention is applied, Fig. 2 is a hydraulic control circuit diagram of the automatic transmission for the same vehicle, and Fig. 3 is a diagram of the direct coupling clutch of Fig. 2. Exploded view of the main parts, Figure 4 is a graph showing the relationship between the working oil pressure of the direct coupling clutch and vehicle speed, Figure 5 is the main flowchart showing the control procedure for the working oil pressure (transmission capacity) of the direct coupling clutch, and Fig. 6 is the graph showing the relationship between the working oil pressure of the direct coupling clutch and the vehicle speed. FIG. 7 is a sub-flowchart showing the control procedure carried out in step 5 of FIG. 6. FIG. 8 is a sub-flowchart showing the control procedure carried out in step 17 of FIG. Different,
A graph showing the relationship between speed ratio and duty ratio in control when the speed ratio enters the reference value region from the weak engagement force region through the reference value approximation region. 10 is a graph showing the relationship between the speed ratio and duty ratio in control when the speed ratio goes from the weak engagement force region through the reference value approximation region and enters the reference value region with the same speed ratio. FIG. 11 is a graph showing the relationship between the speed ratio and the duty ratio in control when the fine adjustment region exceeds the reference value region and returns to the reference value region again without exceeding the fine adjustment region. 7 is a graph showing the relationship between the speed ratio and the duty ratio in control when the speed ratio returns from the reference value region to the fine adjustment region to turn on the solenoid and then returns to the reference value region. T...Torque converter (hydraulic power transmission device), 2
... Pump impeller (input member), 4... Turbine impeller (output member), Cd... Direct connection clutch (direct connection mechanism). Applicant Honda Motor Co., Ltd. Agent Patent Attorney Toshihiko Watanabe', A3 figure, A5 figure

Claims (1)

[Claims] 1. The predetermined parameter value representing the relative slip amount of the input and output members of a hydraulic power transmission device having an input member and an output member is within a predetermined reference range set in advance. In the method for controlling a direct coupling mechanism of a hydraulic power transmission device for a vehicle automatic transmission, which variably controls the transmission capacity of a direct coupling mechanism that mechanically engages the input and output members, the actual measurement of the predetermined parameter value Compare the value with the predetermined reference range value,
Based on the comparison result, the transmission capacity for a predetermined period to be implemented from now on is determined, and a fine adjustment region in which the transmission capacity is finely adjusted to the decreasing side when the parameter value is greater than or equal to the predetermined reference range value is determined based on the predetermined standard. A method for controlling a direct coupling mechanism of a fluid type power transmission device for an automatic transmission for a vehicle, characterized in that the setting is made so as to touch the upper side of a range value. 2. Direct coupling mechanism control of a hydraulic power transmission device of an automatic transmission for a vehicle according to claim 1, wherein the predetermined parameter is a ratio of the respective rotational speeds of the input member and the output member. Method. 3. Direct coupling mechanism control of a hydraulic power transmission device for an automatic transmission for a vehicle as set forth in claim 1, wherein the predetermined parameter is a difference between the respective rotational speeds of the input member and the output member. Method. 4. A direct coupling mechanism control method for a fluid power transmission device for an automatic transmission for a vehicle according to claim 1, characterized in that the transmission capacity is kept constant within the predetermined period. 5. The transmission capacity when the parameter value exceeds the predetermined reference range value and enters the fine adjustment region and then returns to the predetermined reference range value is the transmission capacity when the parameter value exceeds the predetermined reference range value and enters the fine adjustment region. 2. A direct coupling mechanism control method for a hydraulic power transmission device for an automatic transmission for a vehicle according to claim 1, wherein the transmission capacity is set to be smaller than the transmission capacity when the transmission capacity is applied. 6. The automatic transmission for a vehicle according to claim 5, wherein the magnitude of the transmission capacity is determined by a state of change of the parameter value when the parameter value is in the fine adjustment region. Direct connection mechanism control method for fluid power transmission device.