JPS5947552A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE:To reduce shock upon gear-shifting, by adjusting the supply of hydraulic pressure to a friction element which is switched in association with changes of drive ratios in low and high speed ranges, and allowing the friction element to have a suitable overlap. CONSTITUTION:In a transmission unit of fore four-speed and one backward- speed, when the transmission unit is shifted down, for example, from the third speed to the second speed, a control device 112 closes and opens solenoid valves 108, 110, respectively, to actuate a shift control valve 90 so that a four-speed clutch 28 is disengaged, and as well, a 2-3 speed and 4-3 speed shift valve 102 is controlled to communicate an oil passage 376 with an oil discharge passage. Simultaneously, the duty rate of a solenoid valve 106 which is an overlap adjusting device, is changed to release a kick-down brake 30 for setting a drive ratio in a low speed range so that the third-speed is made out of synchronism. Then, a front clutch 24 for setting a drive ratio in a high speed range is made neutral, and pressure oil is fed to the brake 30 after the synchronization of the second speed is detected so that the gear shift to the second speed is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a control device for an automatic transmission, and is intended to reduce shocks caused by shifting.

In general, automatic transmissions used in automatic vehicles selectively operate multiple hydraulically operated friction elements such as clutches and brakes in addition to gear transmissions to obtain multiple drive ratios. When changing gears (shifting), one friction element is released and the other is engaged.

In an automatic transmission equipped with such a gear transmission, selecting the timing of release and engagement appropriately when changing the drive ratio reduces shift shock, maintains ride comfort, and prevents damage to the mechanism. It is also important for the purpose of

For example, when shifting gears, if the gear is released early and the engagement is late, problems will occur during that time, and conversely, if the release is delayed and the engagement is early, both friction elements will be engaged during that time, causing a conflict within the transmission. At the same time, a large overload acts on the friction elements and the seven gear mechanisms, causing damage to the entire system.

In other words, when converting from a low speed drive ratio to a high speed drive ratio,
When the engine is in the driving state, it corresponds to the output torque of the engine. Overlap is provided between the release and engagement described above to completely prevent the engine from idling, and when the engine is in a driven state, an appropriate interval (this It is desirable to fully engage the friction elements responsible for the high-speed drive ratio after the engine speed has decreased to the high-speed drive ratio drive state when the total overlap is 0 or small.

Conversely, when converting from a high-speed drive ratio to a low-speed drive ratio, when the engine is in the driving state, it is desirable to change the timing of disengagement and engagement depending on the vehicle running speed; After the friction element is released, does the engine speed increase or decrease to the low-speed drive ratio drive state with a small overlap? It is then necessary to engage the friction element responsible for the low speed drive ratio to reduce the overlap as the vehicle speed decreases. Particularly at low speeds, it is desirable to substantially eliminate overlap or to minimize overlap.

In this way, it is necessary to increase the overlap at low speeds and to continuously reduce the overlap as the speed increases, but when the engine is in a driven state, the engagement of both friction elements is in a state where the overlap is small, that is, there is no overlap. If there is a pause, the engine braking state of the vehicle is interrupted during that time, and then when the friction element having a low-speed drive ratio engages, a strong engine braking state occurs, which impairs the riding comfort.

Therefore, it is well known that a one-sided brake can be used instead of a brake to achieve these drive ratio conversions fully automatically, but this cannot be applied to all friction elements. Additionally, there is also known a hydraulic control device that detects all changes in the rotational speed of the shaft of a transmission without using a one-way brake, and when synchronization is achieved, supplies hydraulic pressure for engagement to the friction element without any need for transfer. Special Publication No. 54-35631)
However, the structure is complicated and it cannot be applied to electronically controlled systems.

The present invention has been made in view of the above prior art, and provides an automatic transmission that can completely reduce shift shock by giving an appropriate overlap to the friction elements that are switched when the drive ratio is changed according to the vehicle condition. The entire purpose is to provide control equipment.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

First, the automatic transmission to be controlled will be described with reference to FIG. 1 showing its schematic structure. The crankshaft 4 of the engine 2, which is the power source of the vehicle, is directly connected to the pump 8 of the torque converter 6. The torque converter 6 includes a pump 8° turbine lO, a stator 12. The stator 12 is connected to the case 16 through the one-way clutch 14, and the one-way clutch allows the systator 12 to rotate in the same direction as the crankshaft 4, but not in the opposite direction. The structure is unacceptable.

The torque transmitted to the turbine 10 is transmitted by the input shaft 20 to a gear transmission 22 disposed at the rear thereof that achieves four forward speeds and one reverse speed.

The transmission 22 includes three sets of clutches 24, 26, 28.
It is composed of two sets of brakes 30, 32, a one-way clutch 34, and one set of Rapigno type planetary gear mechanism 36. Planetary gear mechanism 36tj:, ring gear 38
．． Long pinion gear 40. Short pinion gear 42
．． Front sun gear 44. Rear sun gear 462 and both pinion gears 40 and 41f are comprised of a carrier 48 that is rotatably supported and is also rotatable, the ring gear 38 is connected to the output rack 150, and the front sun gear 44 is connected to the kickdown drum 52. A low reverse brake 32 and a one-way clutch 34 are connected to the input shaft 20 via the front clutch 24, the rear sun gear 46 is connected to the input shaft 20 via the carrier clutch 26, and the carrier 48 is functionally arranged in parallel. 4, which is fully connected to the case 16 and is disposed at the rear end of the transmission 22.
It is connected to the input shaft 20 via a speed clutch 28.

The kickdown drum 52 can be fixedly connected to the case 16 by a kickdown brake 30. The torque passed through the planetary gear mechanism 36 is transferred to the output shaft 5.
The output is transmitted from the output gear 60 fixed at zero to the driven gear 64 via the shear idle gear 62, and further to the transfer shaft 66 fixed to the driven gear 64 and the helical gear 6.
8 to a differential gear device 72 to which a drive shaft 70 is connected.

Each of the above-mentioned clutches and brakes is composed of a friction engagement device equipped with an engagement piston device or a servo device. It is operated by hydraulic pressure generated by an oil pump 74 shown in FIG. The hydraulic pressure is selectively supplied to each clutch and brake by a hydraulic control device, which will be described later, according to the operating state detected by various operating state detection devices, and the hydraulic pressure is selectively supplied to each clutch and brake according to the operating state detected by various operating state detection devices. As shown in Table 1,
Four forward speeds and one reverse speed are achieved. In the same table, the ○ mark indicates the engagement state of each clutch or brake.
The mark indicates that the carrier 4 is activated by the action of the one-way clutch 34 just before the low reverse brake 32 is engaged during gear shifting.
8 is shown to have stopped rotating.

Table 1 Next, an electrohydraulic control device for achieving the gears shown in Table 1 in the gear transmission 22 shown in FIG. 1 will be described.

The hydraulic control device shown in FIG. 2 includes an oil sump 76, an oil filter 78. The oil is discharged from the oil pump 74 through the oil passage 80 and is supplied to each hydraulic chamber in order to operate the silencer torque converter 6 and the piston devices or servo devices of each clutch 24, 26, 28 of the transmission 22, and brake 30, 32. It controls the hydraulic pressure depending on the operating condition, and is mainly controlled by the pressure regulating valve 82. Torque converter control valve 84° pressure reducing valve 862 manual valve 88. Shift control valve 90° Rear clutch control valve 92
．． N-R control valve 94°Hydraulic control valve 96 during gear shifting. N-D
Control valve 98° 1-2 speed shift valve 100. 2-3 speed and 4 speed
-3-speed shift valve 102, 4-speed clutch control valve 104, and three solenoid valves 106, 108, 110 are all constituent elements, and each element is connected by an oil passage. Among these components, a shift control valve 90.1-2 speed shift valve 100 is used as a switching valve that completely switches the oil passages to each friction element 24, 26.28° 30.32 for switching the drive ratio.
．． The 2nd-3rd speed and 4th-3rd speed shift valve 102 and the 4th speed clutch control valve 104 function and an overlap adjusting device for providing an overlap amount to the torque capacity of the friction element is a hydraulic control valve 96, N-D during gear shifting. The electronic control system M includes the control valve 98 and the solenoid valve 106.
112.

Each of the solenoid valves 106, 108, and 110 has the same structure, and is a non-energized solenoid that controls the opening and closing of each orifice 114, 116, and 118i by electric signals from an electronic control unit 112. Valve, solenoid 12o.

122.124. Valve body 126t128.13 arranged in the same solenoid and opening and closing each orifice 114 to 118
0 and a spring 132 that biases the valve body in the fully closing direction,
134,136.

The electronic control unit 112 detects the operating state of the vehicle and controls the solenoid valve 108 . A solenoid valve 1 that is fully built-in, such as an operating state determining device that determines all opening/closing combinations of 110, and a shift detection device that detects all the start of shifting, and which performs duty control.
06 operation.

The oil pressure is controlled by stopping and changing the valve opening time by controlling the single pulse current width of the 50 Hz pulse current supplied to the solenoid valve 106, and the solenoid valve 108, 110.
Its input elements include an engine load detection device 138 that detects the throttle valve opening (not shown) or intake manifold negative pressure of the engine 2, and a rotation speed detection device 14o of the engine 2, as shown in FIG. A rotation speed detection device 142 for the kickdown drum 52 shown in FIG. It consists of a lever selection position detection device 148, an auxiliary switch selection position detection device 150, and the like.

Pressure oil discharged from the oil pump 74 flows through the oil passage 160.
A pressure regulating valve 821, a manual valve 88, and a pressure reducing valve 86 are guided through the pressure regulating valve 821 and the manual valve 88°.

The manual valve 88 has 4 positions (N, R, I), and when it is in the D position, the oil passage 160? r oil passage 172°174
As shown in Table 2, the solenoid valve 108,1
10 ON/OFF combinations, the gear transmission 22 is caused to achieve all forward operating states of 1st to 4th speeds,
When the N position is reached, the oil passage 160 is communicated only with the oil passage 174, and the oil passage 172 is communicated with the oil drain port 176, so that the gear transmission 22 achieves a neutral state, and when the R position is reached, the oil passage 16 is communicated with the oil passage 174.
0 is communicated with the oil passages 178 and 180 to cause the gear transmission 22 to achieve a reverse operating state (shift stage), and when the P position is reached, all the oil passages all drain ports 176 or It communicates with the oil drain path 182 and brings the gear transmission 22 into a substantially neutral state.

The pressure regulating valve 82 in Table 2 has a spool 188 and a spring 190'i having pressure receiving surfaces 184 and 186, and when the hydraulic pressure from the oil passage 160 acts on the pressure receiving surface 184 via the oil passage 174, the oil pressure k of the oil passage 160 is The pressure is regulated to a constant pressure of 6 Ky/cA (hereinafter referred to as line pressure), and an oil passage 160 is installed on the pressure receiving surface 186.
When hydraulic pressure from the oil passage 178 acts on the oil passage 160
The hydraulic pressure is adjusted to 14.6 (K/d).

The torque converter control 1'84 has a spool 192 and a spring 194, and a pressure oil basin led from the pressure regulating valve 82 through an oil passage 196, and a pressure oil basin connected to the pressure regulating valve 82 through a passage 198'e formed in the spool 192. The pressure is adjusted to 2.5Ky/crl depending on the balance of oil passage 20.
0'i to the torque converter 6. Note that the oil discharged from the torque converter 6 is supplied to each lubricating section of the transmission via the oil cooler 202t.

Pressure reducing valve 86d has a spool 204 and a spring 206, and a pressure receiving surface 208 formed opposite to the spool 204
, 210 and the biasing force of the spring 206, the oil pressure from the oil passage 160 is
The pressure is adjusted to 2.4 kg/d and supplied to the oil passage 212.

The pressure regulating oil (reducing oil) led to the oil passage 212 passes through the Oriswiss 214Th to the N-R control valve 94° and the oil pressure control valve 96.
and reaches the orifice 114 of the solenoid valve 106.

The N-R control valve 94 has pressure receiving surfaces 216, 218° 220, a spool valve 222 and a spring 224, and has hydraulic pressure acting on the pressure receiving surface 216 and pressure receiving surfaces 218, 2.
The oil pressure in the oil passage 226 is regulated to a predetermined value by a balance between the oil pressure due to the area difference between the oil passages 20 and the resultant force of the urging force of the spring 224.

The hydraulic control valve 96 includes a spool valve 234 and a spring 236 in which pressure receiving surfaces 228, 230° 232 are formed, and the hydraulic pressure acting on the pressure receiving surface 228 and the pressure receiving surfaces 230, 23 are
The oil pressure in the oil passage 238 is regulated to a predetermined value by balancing the oil pressure due to the area difference between the two and the resultant force of the biasing force of the spring 236.

Note that the adjusted hydraulic pressure led to the oil passage 226 is used to control the low reverse brake 32 when obtaining the reverse gear stage, and the adjusted oil pressure led to the oil passage 238 is used to control the forward or backward movement of the vehicle. In the stopped state, the front clutch 24
．． Rear clutch 26. Kickdown brake 30j controls the low reverse brake 32.

The solenoid valve 106 is operated by the electronic control device 1 with a constant frequency pulse current of 50 Hz whose pulse width is changed according to the operating state.
The duty is controlled by R'' 42, and the ratio of opening/closing time of the orifice 114 is changed by changing the pulse width to control the oil pressure in the oil passage 212 on the downstream side of the orifice 214, that is, the N-R control valve 94. It controls the hydraulic pressure P1 acting on the pressure receiving surface 216 of the hydraulic control valve 96 and the pressure receiving surface 228 of the hydraulic control valve 96. By changing the hydraulic pressure, the supply pressure to each friction element is changed and the amount of overlap is adjusted. For example, the orifice 214 diameter is 0.8 tea, orifice 1
If the diameter of 14 is 1.4, the above oil pressure P1 is approximately 0.3.
~2. The pressure is adjusted between IKf/cd, and the adjusted oil pressure generated in the oil passages 226 and 238 is approximately OKf/-.
and the supply oil pressure (the oil pressure in the oil passage 180 or the oil passage 172).

In addition, the operation start timing and the operation period of the solenoid valve 106 are as follows: In addition to the engine load detection device 138, each of the rotation speed sensors 140, 142, and 144, the electronic control device 11
2. A shift detection device that detects the start of the shift built into 2;
It is determined according to an electrical signal from a maintenance timing detection device etc. consisting of two rotational speed sensors 142 and 144.

The shift control valve 90 is controlled by a combination of opening and closing of the solenoid valves 108 and 110, and includes three spools 240, 242, 244 and two stoppers 24.
6,248, and the spool 240 has a land 250,
252. An oil passage 258 is provided which fully communicates with the oil chamber 256 on the left side of the door 250 (represented by the annular groove 254 and the intervening groove 254),
The spool 242 has lands 260°262 with different diameters,
The spool 244 is provided with an annular groove 264 and suppressing portions 266 and 268 that come into contact with each spool 240, and the spool 244 is provided with lands 270 and 272, an oil chamber 276 on the right side of the groove 274 and the land 272. Fully communicating oil passage 27
8 is provided. Also, a stopper 246 is interposed between the spools 240 and 242 and fixed to the casing, and a stopper 248 is interposed between the spools 242 and 244 and fixed to the casing.
? +'? 264 k via regular Q oil line 2 s o t
The L1 oil passage 280 passes through the orifice 282 to the orifice 116. It communicates with the oil chamber 256 on the left side and the oil chamber 27G on the right side, and also communicates with the oil chamber 286 between the orifice 118 and the spools 240 and 242 through the entire orifice 284.

Rear clutch control l+92 u, land 288, land 290 with a smaller diameter than land 288, and annular groove 29
2, three lands 296, 298° 300 having the same diameter as the land 290, and an annular groove 30.
2, 304, and a spring 308, the hydraulic pressure dy that is guided to the oil chamber 310 on the left side of FIG. 2 and acts on the pressure receiving surface of the land 288 is the second
When the combined force of the hydraulic pressure guided to the oil chamber 312 on the right side of the figure and acting on the pressure receiving surface of the land 300 and the biasing force of the spring 308 becomes greater, both spools 294 and 306 are switched to the right end position in the figure.

Furthermore, when the right end position is reached, hydraulic pressure acts between the lands 290 and 296, so when the hydraulic pressure in the oil chamber 310 is discharged, only the guru 294 moves to the left end, and then the lands 290 and 296 move to the left end.
The pressing force of the hydraulic pressure acting on the left pressure receiving surface of the oil chamber 3 is
The spool 306 moves to the left when the resultant force of the pressing force due to the hydraulic pressure in the spool 12 and the biasing force of the spring 308 becomes small.

The N-D control valve 98 includes a spool 320 provided with lands 314, 316 and an annular groove 318, and a spring 322.
A pressure receiving surface 324 formed on the spool 320,
The spool 320 is selectively switched between the left end position shown in FIG. 2 and the right end position (not shown) depending on the direction of the resultant force of the hydraulic pressure acting on 326 and 328 and the biasing force of the spring 322.

The 1-2 speed shift valve 100 has a spool 330 and a spring 332, and a left end pressure receiving surface 334 of the spool 330.
The line pressure is switched between the left end position shown in FIG. 2 and the right end position (not shown) by supplying and discharging line pressure to the pressure receiving surface 334. When the line pressure is discharged, it is located at the left end due to the biasing force of the spring 332.

The 2-3 speed and 4-3 speed shift valves 102 and the 4-speed clutch control valve 104 similarly each have a spool 336.338 and a spring 340.342, with each spool 336,3
On the left side of 38 are hydraulic pressures 344, 34 to which line pressure is led.
6, oil chambers 348, 350 are formed on the right side, and each spool can be selectively switched to the left end position shown in FIG. 2 or to the right end position (not shown).

Next, the operation of the hydraulic control device and the shift control will be explained, but since the normal shift control is already known, a detailed explanation will be omitted (Japanese Patent Application No. 14423/1989).
(See No. 7, etc.)

First, overlap, which is a problem in the present invention, will be explained.

The torque capacity of the friction element for setting all low-speed drive ratios is T.
l, T2 is the torque customer side of the friction element for setting the high-speed drive ratio, and constant k represents the piston area, number of clutches, clutch radius, friction coefficient, etc. of each friction element.
If all 32, the amount of overlap C is defined by the following equation.

C=3. +a2*T2 Therefore, by changing the oil pressure supplied to each friction element, T1 is changed to fc u T2, and the overlap amount C is
Therefore, in the case shown in Fig. 3(a), the amount of overlap C does not change constant.
In the case υ) in the figure, the overlap amount C changes.

Next, the first invention of the present application will be explained using an example of downshifting from 3rd speed to 2nd speed. In the above hydraulic control device, as shown in FIG. The oil chamber 38 on the release side of the kickdown brake 30, which is a friction element for setting the ratio, and the hydraulic piston of the front clutch 24, which is a friction element for setting the high-speed drive ratio, are communicated through an oil passage 376. Therefore, in order to cause the third speed to become out of synchronization, the pressure oil supplied to the front clutch 24 must be at full low pressure to be supplied to the engaging side oil chamber 366 of the kickdown brake 30. Release [! :I completely reduce the drained oil discharged from the oil chamber 382 t'I' L and at the same time 2-3 speed and 4-3 speed shift valve 1O-
It is good to move to the 2nd speed side (the left end position in Figure 2), but if the supply pressure to the engagement side oil chamber 366 of the kickdown brake 30 is kept low, the kickdown brake will not be ready for engagement. Even if the oil pressure is increased at the same time as synchronization of the second gear is completed, the kickdown brake 30 cannot be engaged in time, and it is necessary to supply high pressure oil until the brake piston moves and is ready for engagement. On the other hand, if the high-pressure oil remains fully supplied, the front clutch 24, which has a shockingly strong engagement force, will also be released at the same time as the kickdown brake 30 starts to engage, resulting in a shock.

Therefore, when the electronic control unit 112 issues a shift signal from the third speed to the second speed from each detection signal obtained depending on the driving state of the vehicle, the solenoid valve 108 is de-energized and the solenoid valve 110 is energized. As a result, the hydraulic pressure in the oil passage 372 is discharged by the operation of the shift control valve 90, and the spool 338 of the 4-speed clutch control valve 104 moves to the right end, and the oil pressure in the oil passage 372 is discharged.
6 hydraulic pressure is discharged through the oil passage 388, the 4th speed clutch 28 is released, and the spool 336 of the 2nd-3rd speed and 4th-3rd speed shift valves 102 is moved to the left end, and the oil path 376 becomes an oil drain path. Communicate with. At the same time, as shown in Figure 4,
In response to the shift start signal, the electronic control device 112 changes the duty rate of the solenoid valve 106, which is an overlap adjustment device, and the oil passages 238, 1-2 are controlled from the hydraulic control valve 96.
Hydraulic pressure is supplied to the engagement side oil chamber 366 of the kickdown brake 30 via the speed shift valve 100 and the oil passage 364.
The high pressure (line pressure) is supplied until a predetermined time t1 until the brake piston moves and is ready for engagement, which is determined in advance based on the supplied oil pressure and the volume of the engagement side oil chamber 366. After the predetermined time t□ has passed, the solenoid valve 1 is fully engaged and the kickdown brake 30 is fully engaged.
Increase the duty rate of 06 and change to medium pressure state. As a result, the front clutch 24 is released without being affected by the oil drained from the release side oil chamber 382 of the kickdown brake 30, and the third speed becomes out of synchronization.
Speed out of synchronization tL'f! : The rotation speed detection device 142 of the kickdown drum 52, which is a synchronization detection device, and the driven gear 64
The detection signal is detected by comparing the detection signal with the rotation speed detection device 144 of
The torque capacity of the friction elements 24 and 30 is reduced and the overlap amount C is reduced to bring the gear transmission 22 into a substantially neutral state, and the overlap amount Ct-0 (a state in which the torque capacities of both friction elements 24 and 30 are 0 and there is an interval). do. And the second
Completion of speed synchronization is determined from the detection signals of the two rotation detection devices 142 and 144, which are synchronization detection devices, and the oil pressure supplied to the kickdown brake 30 is immediately switched from low pressure to high pressure based on this second speed synchronization signal, and an overramp is performed. Takashi C o
, the engagement oil pressure of the kickdown brake 3o, which is a friction element on the second speed side, is increased to complete the shift from the third speed to the second speed. In addition, taking into consideration the delay in boosting the voltage from low voltage to high voltage after second speed synchronization is detected, synchronization is actually considered to be completed when the speed is about 300 rpm before synchronization.

In this way, the duty ratio of the solenoid valve 106 is changed between the electronic control device 112 and the kickdown brake 3o and the front clutch 27.1! : o # - By changing the hull wrap amount ok, the kick-down brake 3o is engaged without shock, and a shift from 3rd gear to 2nd gear is achieved.

In the above embodiment, the hydraulic pressure is changed from high pressure to medium pressure to low pressure to high pressure. However, except for the medium pressure state, it may be changed from high pressure to low pressure to high pressure. Shorter shift time by changing the speed! '(c-Fi will be used. Also,
The present invention is applicable not only to a downshift from 3rd speed to 2nd speed, but also to a downshift from 4th speed to 3rd speed, in which engagement and release of the kickdown brake 3 (and front clutch 24 are reversed).

Next, the second invention of the present application will be explained using an example of a downshifter from third speed to second speed. Although the present invention has almost the same configuration as the embodiment of the above invention, The difference is that a stroke detection device 400 for detecting the entire stroke position is provided on the rod 368 of the hydraulic piston in order to directly detect the completion of engagement preparation of the kickdown brake 3o.

This stroke detection device 400 is shown in FIGS.
) and crest), a stepped portion is formed at the proximal end of the rod 368 to which the hydraulic piston of the kickdown brake 30 is attached. A sleeve 402 formed of a conductor such as stainless steel and having a short length of about 131 mm is slidably attached to the stepped portion on the outer periphery, and this stroke L of about 1+ m is attached.
The proximal end is fixed by a retaining ring 404 so as to maintain the tk, and the proximal end is biased by a screw IJ ring 406. A hydraulic piston 74 is attached to the threaded portion of the outer periphery of this sleeve 402.
08 is screwed together and fixed with a nut 410, and a spring 3 is inserted between the hydraulic piston 408 and the release side oil chamber 382.
70 is interposed. On the other hand, an insulating cap 412 made of an insulator such as resin is attached to the base end of the rod 368, a stopper 414 made of stainless steel, and a camp 4 which is a resin molded body attached to a cover 416.
18 and the stainless steel washer 420.
6) where 02 is pushed to the proximal end by spring 406
0 between the rod 368 and the insulating cap 412 in the state of
．． A gap of about 1 to 0.4 wires is formed. And the ring 42 in the center of the cap 418
2. Stopper 414. Contact 426° Sleeve 402. Hydraulic piston 408. An energization path is formed through the spring 370vi, which turns ON at the normal hydraulic piston position, but when pressure oil is supplied to the engagement side oil chamber 366 and the hydraulic piston 408 is pushed, the kickdown brake 3° is activated. The sleeve 402'tr is energized until just before the lock is engaged.
7'lJ link 406t - rod 368 without shrinking
move. Then, just before bonding, rod 368
Since the movement resistance increases, the hydraulic piston 408 moves by the stroke L1 while compressing the spring 406tl. As a result, the stopper 414 and the sleeve 4
02, the stopper 414 can only move by the gap L2 due to the insulating cap 412, and the contact 426 is opened and the current-carrying circuit is turned off.

In this way, the position immediately before the kickdown brake 3o is engaged can be electrically detected.

Note that a gap may be formed between the retaining ring 404 and the insulating cap 412.

Therefore, when the electronic control unit 112 issues a shift signal from the third speed to the second speed based on each detection signal obtained depending on the driving state of the vehicle, the solenoid valve 108 is de-energized and the solenoid valve 11O is energized. In this state, the hydraulic pressure in the oil passage 372 is discharged by the operation of the shift control valve 90, and the spool 338 of the 4-speed clutch control valve 104 moves to the right end, and the hydraulic pressure in the oil passage 386 is discharged through the oil passage 388. As the 4th speed clutch 28 is released, the spools 336 of the 2nd-3rd speed and 4th-3rd speed shift valves 102 move to the left end and open the oil passage 37.
6 is communicated with the oil drain passage. At the same time, as shown in FIG. 7, the duty ratio of the solenoid valve 10G, which is an overlap adjustment device, is changed by the electronic control device 112 in response to a shift start signal.
, the hydraulic pressure supplied to the engagement side oil chamber 366 of the kickdown brake 30 via the 1st-2nd speed shift valve 100 and the oil passage 364. Immediately before the stroke detection device 400 issues an OFF signal, the pressure is lowered and the overrun yfc- is reduced. In this state, the pressure oil of the front clutch 24 is discharged from the oil passage 376, and the 3rd gear is out of synchronization.Then, the neutral state is reached after an overrun of 7°tc=oi, and the 2nd gear is synchronized.Full synchronization detection device Two rotation speed detection devices 1 that are
42 and 144, and based on this detection signal, the hydraulic pressure supplied to the υ kickdown brake 30 is immediately switched from low pressure to high pressure to prevent overrun 7 and amount C.
By increasing the speed by 2, the kick down brake 30 is fully engaged and the shift from 3rd speed to 2nd speed is completed.

In addition, considering the delay time from the detection of the completion of synchronization of the second speed until the voltage is actually boosted, a time of about 300 rpm before synchronization is considered to be the completion of synchronization.

In this way, the electronic control device 112 changes the duty rate of the synlenoid valve 106 to supply high pressure oil until the hydraulic piston of the kickdown brake 30 is just before engagement, and the OFF signal from the stroke detection device 400 is output. The hydraulic pressure supplied to the kick-down brake 30 and the front clutch 24 is decreased to reduce the ramp amount C, and the kick-down brake is immediately applied after synchronization of the second gear is achieved. Since the supply oil pressure is set to a high pressure, the overlap fiC1- is increased, and the torque capacity to the second continuous friction element is switched, the time from the start of the shift from 3rd gear to 2nd gear is shorter than in the case of the first invention. This saves time and enables smooth gear shifting. Also, when shifting from 3rd gear to 2nd gear again during a shift from 2nd gear to 3rd gear, the actual gear shift is not performed until the predetermined Dr constant time t1 elapses, as in the first invention. However, even when the piston position of the kickdown brake 30 is uncertain, it is possible to change gears.

Next, the third invention of the present application will be described. In the present invention, the second invention and #1 have the same configuration, but the control by the electronic control device 112 is different. This is effective for engaging the kickdown brake 30 when shifting from the first speed to the second speed or from the third speed to the fourth speed.

Therefore, an embodiment of the present invention will be described with respect to shifting from the first speed to the second speed of the automatic transmission shown in FIGS. 1 and 2.

When the accelerator pedal is depressed after the first speed has been achieved and the vehicle speed increases, the throttle valve opening sensor 13
8 and the gear rotation speed (vehicle speed) sensor 14-4, the electronic control unit 112 issues a command to achieve the second speed, the solenoid valve 108 is de-energized, and the solenoid valve 110 is energized. It will be preserved. Due to this switching, the line pressure of the oil passage 280 is transmitted through the orifice 282 to the annular groove 254. Oil road 258. The spool 240 is guided by the oil chamber 25G, the oil chamber 276, and the annular groove 274, and the spool 240 is connected to the spool 24.
2 to the right and stops when it comes into contact with the stopper 246. Then, the line pressure of the oil passage 172 is guided to the oil passage 362 through the entire annular groove 264.
Since it acts on the pressure receiving surface 334 of the speed shift valve 100 and the pressure receiving surface 346 of the 4th speed clutch control valve 104, both valves 100,
104 spool 330° 338 is moved to the right end position. As a result, the line pressure of the oil passage 238 is supplied to the retention side oil chamber 366 of the kickdown brake 30 via the oil passage 364, and the rod 368 is moved to the spring 370. The pre- and -ki bands (not shown) are brought into engagement with the kickdown drum 52 by being moved to the left against the pressure, while the hydraulic pressure in the oil passage 356 is discharged through the oil passage 226 to apply the low reverse brake 32.
is released and second speed is achieved.

At this time, when the kickdown brake 30 is engaged, the stroke detection device 400 is used, the electronic control device 112 controls the duty rate of the solenoid valve 106, and the oil passage 23
8, that is, the oil pressure supplied to the oil chamber 366 on the engaging side of the kickdown brake 30, is first kept at a high line pressure, and the signal from the stroke detection device 400 is obtained just before engagement. Afterward, reduce the pressure during gear shifts to avoid gear shift shock.

By supplying high-pressure oil until just before the kickdown brake 30 is engaged, it is possible to shorten the ineffective time until the kickdown brake 30 is engaged, allowing the shift to be completed in a short time, and also to reduce shift shock. can.

The kickdown brake 30 is also engaged when shifting from 3rd to 4th gear, but in this case as well, supplying high-pressure oil until immediately before engagement shortens the ineffective time and makes the shift smoother. You can change gears.

Note that in this stroke detection device 400, the stroke L1
If the relationship between the gap Lz and the gap Lz is set to a predetermined value, there is no need to make adjustments even when wear of various parts occurs, such as wear of the brake band. However, as the stroke detection device, it is possible to use other devices such as potentiometers that can directly detect the position of the rod 368.

As described above in detail with the embodiments, according to the present invention, the electronic control device supplies hydraulic pressure to the friction elements.
By adjusting the speed, shift shock can be reduced, and the structure is simpler than that of a hydraulic control device.

[Brief explanation of the drawing]

1 and 2 are a schematic diagram of an automatic transmission, which is one of the application targets of the present invention; FIG. 1 is a schematic configuration diagram of a power transmission section; FIG. 2 is a schematic diagram of a hydraulic control section; Figure 3 (al (
b) is an explanatory diagram of OVERRADZ 7/Summer, respectively, FIGS. 4 and 7 are explanatory diagrams of hydraulic control during gear shifting, FIGS. 5 and 6 (a) Cbl is an illustration of the stroke detection device, FIG. 5 is a sectional view, and FIGS. 6(a) and 6(b) are enlarged sectional views of important parts. In the drawing, 22 is a gear transmission, 24, 26, 28 is a clutch, 30, 32 is a brake, 34 is a one-way clutch, 90 is a shift control valve, 96 is a hydraulic control valve during gear shifting, 98 is N-D Control valves, ioo 1-2 speed shift valve, 102 2-3 speed and 4-3 speed shift valve, 104 4 speed clutch control valve, 106 solenoid valve, 112 electronic control device, 142.144 rotation number detection device; 400 is a stroke detection device; Patent applicant: Mitsubishi Motors Corporation Tawara, patent attorney, Shibe Mitsuishi (and one other person)

Claims (3)

[Claims] (1) In an automatic transmission equipped with a gear transmission with multiple drive ratios between input and output shafts, a hydraulically actuated friction element is used to set all low-speed drive ratios, and a hydraulically actuated friction element is used to set all high-speed drive ratios. a friction element, a synchronization detection device that detects whether both of the above drive ratios have been achieved, a switching valve that switches the oil path to the friction element to switch between the high speed drive ratio and the low speed drive ratio, and a synchronization detection device that detects whether both of the above drive ratios have been achieved; 4-ramp for giving an overlap in the torque capacity of both friction elements when changing the drive ratio; 7 When the high speed drive ratio is out of synchronization when shifting from a high speed drive ratio to a low speed drive ratio, O7 (- When the overlap amount is small and the low speed drive ratio is synchronized, the overlap amount is 1. A control device for an automatic transmission, comprising: an electronic control device for controlling the transmission so that the transmission speed increases. (2) In an automatic transmission equipped with a gear transmission having multiple drive ratios between input and output shafts, a hydraulically operated friction element for setting a low-speed drive ratio and a hydraulically operated friction element for setting a high-speed drive ratio a synchronization detection device that audibly detects whether the low-speed drive ratio has been achieved, a switching valve that switches oil passages to both friction elements when switching between the high-speed drive ratio and the low-speed drive ratio, and a high-speed drive ratio. and a stroke detection device for detecting the entire stroke position of the hydraulic piston of the friction element for setting the low-speed drive ratio; The hydraulic pressure supplied to the overlap adjustment device adjusts the geo-parallel configuration, and when the hydraulic piston of the low-speed friction element reaches a position on the verge of locking when shifting from a high-speed drive ratio to a low-speed drive ratio, the total amount of overlap is reduced. What is claimed is: 1. A control device for an automatic transmission, comprising: an electronic control device that controls the amount of overlap to be large when low-speed drive ratio synchronization is achieved. (3) In an automatic transmission equipped with a gear transmission having a plurality of drive ratios between the input and output shafts, a hydraulically operated friction element for setting the plurality of drive ratios, and a drive from one drive ratio to the other. A stroke detection device detects the stroke position of a hydraulic piston of a hydraulically operated friction element for setting the other drive ratio when converting to a drive ratio, and the stroke position when changing from one drive ratio to the other drive ratio. An automatic transmission comprising an electronic control device that supplies high-pressure oil to a hydraulic piston until it is just about to engage, and controls the supply of appropriate hydraulic pressure during gear shifting based on a detection signal from a detection device. Control device.