JPS60231059A - Shift shock reliever for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent premature wear in a friction element and a power loss from occurring, by making friction element operating hydraulic pressure a basis, while setting a value, having corrected this hydraulic pressure as far as the specified value, down to the desired value. CONSTITUTION:A hydraulic fluid pressure desired value Paim of a friction element necessary from the standpoint of shift shock prevention is determined after making hydraulic fluid pressure P1 in time of shift starting a basis and correcting this pressure as far as the specified value P0. With this constitution, even if there are variations in the friction element as a product and a secular change, the desired value Paim comes to a proper value adding these factors so that these following cases that sufficient relief from a shift shock will not come to fruition as the desired value is too high and the occurrence of a shift lag due to too low in the desired value as well as a power loss due to an undue slip in the friction element and premature wear in the friction element are all preventable.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field The present invention relates to a device for reducing shock during gear shifting of an automatic transmission, so-called shift shock.

An automatic transmission transmits power from the engine to the drive wheels to drive a vehicle, but at this time it shifts along a scheduled shift line depending on the vehicle speed and engine load (e.g. throttle opening/opening). It is possible to automatically determine a gear position, and to shift up or down to this gear position, thereby allowing the vehicle to travel at automatic gears.

By the way, during gear shifting, especially when upshifting, it is normal for the upshifting to be carried out in a so-called "war-on" state with the accelerator pedal depressed, so as explained below, it is important to avoid the shift shock from becoming large. Inevitable. During this shift shock, the torque of the transmission output shaft is instantaneously 1. , 1. After the 1 → 2 shift up command and the 2 → 8 shift up command, the changes generally occur as shown in these figures, although they differ depending on the type of shift door, and the T1. This occurs because a higher peak torque is generated by T2 (see also FIGS. 12 and 14). These peak torques are caused by the sudden change in engine speed when the gear changes due to upshifting, and the combined rotational force of the engine's rotational inertia and driving force is rapidly transmitted to the transmission output shaft. .

For this reason, conventionally, a technique has been proposed in which the hydraulic pressure of a friction element that is hydraulically operated during upshifting is set to a target value required to prevent shift shock during its operation (during gear shifting). As shown in
During gear shifting, the hydraulic pressure of the friction element is maintained at a value necessary to prevent gear shift shock, and the rate of increase in the hydraulic pressure is kept small to suppress changes in the torque transmission capacity of the friction element to the transmission output shaft. There is a known technology to limit transmission torque and reduce gear shift shock.

By the way, if the above-mentioned target value is too high, it may be desired to sufficiently reduce the shift shock; if it is too low, the shift may not be completed at any time, and power loss may increase due to excessive slipping of the friction element, or the friction element may be damaged early. causing wear and tear,
The above target values must be appropriate.

However, due to product variations in friction elements, changes over time, etc., the appropriate target value differs from automatic transmission to automatic transmission, and even for the same automatic transmission, it changes over time. However, in the conventional technology, it is not possible to set the target value in consideration of these factors, and the above-mentioned problem cannot be avoided if the target value 41μ is too high or too low.

(δ) Purpose of the Invention The present invention is based on the fact that product variations in friction elements, changes over time, etc. are all reflected in changes in the friction element operating oil pressure at the time of the start of operation. By setting the target value as a value obtained by increasing the oil pressure and correcting it by a predetermined amount, the target value takes into account product variations in friction elements and changes over time, etc. The purpose is to solve the above-mentioned problem that the target value deviates from the bipositive value.

(4) Purchasing the Invention For this purpose, the gear shift shock reducing device of the present invention is capable of shifting gears by hydraulically operating selected friction elements, as shown in FIG. In an automatic transmission equipped with a hydraulic pressure control means for setting the hydraulic pressure to a target value required for preventing gear shift shock, the automatic transmission includes a hydraulic pressure detecting means for detecting the hydraulic pressure of the friction element, and detecting the start of operation of the friction element. and target operating oil pressure determining means for instructing the operating oil pressure control means to set a value obtained by correcting the operating oil pressure at the time of starting the operation of the friction element by a predetermined amount as the target value. do.

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

FIG. 2 schematically shows the power transmission portion of a lock-up automatic transmission with 8 forward speeds and 1 reverse speed, which is equipped with the shift shock reducing device of the present invention. However, the present invention is not limited to this automatic transmission. ! It is obvious that the present invention can be applied to any automatic transmission having a plurality of gears.

The power transmission part in FIG. 2 includes the crankshaft Φ of the prime mover (engine), a lock-up torque converter equipped with a lock-up ff1lI717, an input shaft 7, a front clutch 1o4, a rear clutch 1o6, a second brake 106, a low reverse brake 107,
one-way brake 108, intermediate shirt) 109, first planetary gear group 11o1 second planetary gear group 111. Output shaft (transmission output shaft) 112, first governor valve 1
18, the second governor valve 114 and the oil pump 18 are installed at the bottom of the groove. The torque converter consists of a pump impeller 8, a turbine impeller 8, and a stator impeller 9. The pump impeller 8 is driven by the crankshaft 4, and the torque converter hydraulic oil contained therein is rotated into the shaft 7. Torque is applied to the turbine wheel 8 fixed to the Torque is further transmitted to the transmission gear train by the input shaft door. The stator wheel 9 is placed on a fixed sleeve 12 via a one-way clutch 10. one way clutch 1
0 does not allow the stator wheel 9 to rotate in the same direction as the crankshaft, that is, in the direction of the arrow (hereinafter referred to as normal rotation). The first planetary gear group 110 rotates and revolves simultaneously while meshing with an internal gear 117 fixed to the intermediate shaft 109, a thick @ gear 119 fixed to the hollow conduction shaft 118, an internal m gear 117, and a sun gear 119. A planetary gear support 121 supports the planetary gear 120 fixed to the output shaft 112. A gear gear 122, a sun gear 128 fixed to the hollow conduction shaft 118, an inner mm wheel 122
OJ: H: Consists of a planetary gear 124-, which is a small gear of 2 Wi or more that can rotate and revolve simultaneously while meshing with the sun gear 1213 (7), and a planetary gear support 125 that supports the planetary gear 124. front clutch 10
The shaft connects the input shaft 7 driven by the turbine impeller 8 and the hollow transmission shaft 7) 118, which rotates together with both sun gears 119 and 128, via a drum 126, and the rear clutch 105 is connected to the intermediate shaft 109. It serves to connect the input shaft 7 and the internal gear 117 of the first planetary gear group 110 via the input shaft 7. The second brake 106 is a drum 1 fixed to a hollow transmission shaft 118.
By winding and tightening 26, both sun gears 1191
128 is fixed, and the low reverse brake 107 functions to fix the planetary gear support 125 of the second planetary gear group 111. The one-way brake 108 is a planetary gear support 125
The structure is such that forward rotation is allowed, but reverse rotation is not allowed.

The first governor valve 113 and the second governor valve 114 are fixed to the output shaft 112 and generate governor pressure according to the vehicle speed.

Next, a description will be given of the power transmission train when the speed selection rod is set to the D (forward automatic shifting) position.

In this case, only the rear clutch 105, which is a forward clutch, is initially engaged. Power that has passed from the engine through the torque converter 1 is transmitted from the input shaft 7 to the inner gear 117 of the first planetary gear group 110 through the rear clutch 105.

The internal gear 117 rotates the planetary gear 120 in the normal direction.

Therefore, the sun gear 119 reverses, and the thick 11dRf of the second planetary gear group 111 rotates integrally with the thick @ gear 119.
#2nd planetary gear group 11 to reverse #t1', 1z8
The first planetary gear 124 rotates normally. One-way brake 108
prevents sun gear 128 from reversing planetary gear support 125 and acts as a forward reaction brake. Therefore, the internal gear 122 of the second planetary gear group 111 rotates normally. Therefore, the output shaft 112, which rotates integrally with the internal gear 122, also rotates in the normal direction, and the reduction ratio of the first forward speed is obtained. In this state, when the vehicle speed increases and the second brake 106 is engaged, the input shaft 1
The power that passes through the rear clutch 105 is transferred to the internal gear 117.
transmitted to. The second brake 106 is a drum 126
is fixed, preventing rotation of the sun gear 119 and functioning as a forward reaction brake. For this reason, the planetary gear 120 revolves around the stationary sun gear 119 while rotating on its own axis, and therefore the planetary gear support 121 and the output shaft 112 integrated therewith are decelerated, but in the first speed. It rotates forward at a higher speed than the normal speed, and the reduction ratio of the second forward speed is obtained. When the vehicle speed further increases, the second brake 106 is released and the front clutch 104 is engaged, the power transmitted to the input shaft 7 is transmitted to the internal gear 117 via the rear clutch 105 on one side, and the front clutch 104 on the other hand. The signal is transmitted to the sun gear 119 via the . Therefore, the internal gear 117 and the thick gear 119 are interlocked, and together with the planetary gear support 121 and the output shaft 112, they all rotate normally in the same rotational relationship to obtain the eighth forward speed (gear ratio 1). In this case, the input clutches are the front clutch 104 and the rear clutch 105, and since torque is not increased by the planetary gear, neither of the reaction brakes works.

Next, a description will be given of the power transmission train when the selection rod is set to the R (reverse travel) position.

In this case, the front clutch 104 and the reverse spring gear 107 are engaged. The rigid force that has passed from the engine through the torque converter 1 is transmitted from the input shaft 7 through the front clutch 104 and the drum 126 to the sun gear 119.
, 128. At this time, since the rear planet carrier 125 is fixed by the low reverse brake 107, the internal gear 122 is decelerated and reversed by the normal rotation of the sun gears 119 and 128, and the output shaft 112 rotates integrally with this internal gear.
The reverse reduction ratio can be obtained from .

FIG. 3 shows the hydraulic system of the speed change control device related to the above-mentioned automatic transmission together with the device of the present invention, in which the oil pump 18
, line pressure adjustment valve 128, pressure increase valve 129, torque comparator 511 speed selection valve iao, first governor valve 118, second governor valve 114.1-2 shift valve 131, 2-8 shift valve 182, throttle pressure reduction valve 138 , cut-down valve 1
84, second lock valve 185.2-8 timing valve 1
86, solenoid downshift valve 187, throttle backup valve 188, vacuum throttle valve 189,
Vacuum diaphragm 140, front clutch 10
4. Consists of a rear clutch 105, a second brake 106, a servo 111, a low reverse brake 107, and a hydraulic circuit network.

The oil pump 18 is driven by the driving force 1 via the crankshaft and the pump impeller 8 of the torque converter 1, and during engine operation always sucks up oil from the reservoir 14+2 through a strainer 148, from which harmful dust has been removed. Send to.

The oil is regulated to a predetermined pressure by the line pressure regulating valve 128, and is used as working oil pressure for the torque converter 1 and the speed selection valve 1.
Sent to 80. The line pressure regulating valve 128 is connected to the spool 17
2 and a spring 178, and the spring 17 is attached to the spool 172.
8, the throttle pressure of the circuit 165 and the line pressure of the circuit 156 act through the spool 17 of the pressure booster valve 129, and the forces generated by these act on the line from the circuit 144 through the orifice 175 above the spool 172. pressure and pressure acting from circuit 176. The hydraulic pressure of the torque converter 1 is determined by the hydraulic oil outflow passage 51 and the maintenance oil after the oil introduced from the circuit 1 into the circuit 145 via the line pressure regulating valve 128 flows into the torque converter 1 through the hydraulic oil inflow passage 60. While being discharged through the pressure valve 146, the pressure is maintained within a certain pressure by the pressure holding valve 146. Above a certain pressure, the pressure holding valve 146 is opened and oil is sent further from the circuit 141 to the rear lubrication section of the power transmission mechanism. When this lubricating oil pressure is too high, the IJ IJ-7 valve 148 opens and the pressure is reduced. On the other hand, lubricating oil is supplied from the circuit 145 to the front lubricating section of the power transmission mechanism by opening the front lubricating valve 149. The speed selection valve 180 is a manually operated fluid direction switching valve, which is composed of a spool 150 and is connected to a speed selection rod (not shown) via a linkage.
This is to switch the pressure feeding passage. The state shown in FIG. 8 is when the line pressure circuit 14 is in the N (neutral) position.
41 is open to ports d and e.

The first governor valve 118 and the second governor valve 114 actuate the 1-2 shift valve 181 and the 2-8 shift valve 182 by the governor pressure generated during forward travel to perform an automatic gear change operation, and also reduce the line pressure. When the speed selection valve 180 is in the OFF, L and OFF positions, the hydraulic pressure is transmitted from the line pressure circuit 144 to the second port of the speed selection valve 180.
When the vehicle reaches the governor valve 114 and the vehicle is running, the governor pressure regulated by the second governor valve 114 is sent to the circuit 157 and introduced to the first governor valve 118, and when the vehicle speed reaches a certain speed, the governor pressure is regulated by the spool 177 of the first governor valve 118. moves, the circuit 157 becomes conductive with the circuit 15B, and governor pressure is generated, and the governor pressure is transferred from the circuit 158 to the 1-2 shift valve 181.
It is counterbalanced by respective springs acting on each end face of S2-8 shift valve 132 and cutdown valve 184 and forcing these valves to the right. Also, a servo that connects the circuit 158, circuit 161, and circuit 162 from port 0 of the heat speed valve 180 to supply the second brake 106;
1 in the middle of the hydraulic circuit reaching the engagement side hydraulic chamber 169 of 1.
-2 shift valve 181 and second lock valve 135 are provided separately, and a circuit 152 that reaches from boat b of speed selection valve 180 to second lock valve 1135 is provided.

Therefore, when the selection rod is set to the D position, the spool 160 of the speed selection valve 180 moves and the line pressure circuit 144 is turned off.
, b and C. Hydraulic pressure is baud) From a to circuit 15
A portion of the spool 178 is pushed upward by the spring 179 and is lowered by the hydraulic pressure acting from the boat b via the circuit 152. Conducting rotation 1
61 and 162 are not blocked, and the 2-3 shift valve 18 is connected from the circuit 167 through the re-orifice 166.
2, from boat C it passes through circuit 158 to reach second governor valve 114, rear clutch 105 and 1-2 shift valve 181, and the transmission enters the first forward speed state. In this state, when the vehicle speed reaches a certain speed, the spool 160 of the 1-2 shift valve 181, which is pressed to the right by the knob 169, moves to the left due to the governor pressure of the circuit 168, shifting from the first forward speed to the second forward speed. Circuit 1
58 and the circuit 161 are connected, and the oil pressure is transferred to the second lock valve 13.
5 from the circuit 162 to the engagement side hydraulic chamber 1 of the servo 141
69, the second brake is engaged for 106 minutes, and the transmission enters the forward state described in the second section. In this case, 1-2 shift valve 1
81 is small-sized, the spool 160 moves to the left with the required deviation q without increasing the linkage of the shift points, and an automatic shift action from the first forward gear to the second gear is performed. When the vehicle speed increases further and reaches a certain speed, the governor pressure of the circuit 158 overcomes the spring 168 and the spool 1 of the 2-8 shift valve 182
64 to the left, circuits 167 and 168 are brought into conduction, and part of the hydraulic pressure from circuit 168 reaches the release side hydraulic chamber 170 of servo 141 to release second brake 106.
A portion reaches the front clutch 104 and engages it,
The transmission is in the 8th forward speed.0 Note that if the driver presses the accelerator pedal hard until the throttle is close to full throttle while driving in the D position, desiring a large acceleration force, a kick occurs. The down switch is turned on, and the downshift solenoid 187a provided opposite to the solenoid downshift valve 187 is energized by energization. As a result, the sprue/I of the solenoid downshift valve 181
/190 is pushed downward from the upper locked position in FIG. 8 by a spring 191. At this time, the power line circuit 180 connected to the circuit 154 is connected to the line pressure circuit 154.
4, line pressure passes through circuit 144.180 to 1-2
The pressure is supplied to the shift valve 181 and the 2-8 shift valve 182 so as to oppose the governor pressure. At this time, if the 8M is running, the spool 164 of the 2-8 shift valve 182 is forcibly pushed by the line pressure from the leftward position to the rightward position against the governor pressure, and at a certain vehicle speed. A forced downshift from 8th gear to 2nd gear is performed within limits, and sufficient acceleration force is obtained. By the way, if the above-mentioned kickdown is performed while running in 2nd gear, the load is large at this time and the speed is low, so the governor pressure is also low, so the line pressure led to the circuit 18o is transferred to the 1-2 shift valve. 181(7) The spool 160 is also engaged from the leftward position against the governor pressure. Therefore, in this case, a forced downshift from second speed to first speed is performed, and even stronger acceleration corresponding to the heavy load can be obtained.

When the speed selection rod is set to the ■ (second forward speed fixed) position, the spool 15G of the speed selection valve 130 moves and the line pressure circuit 144 is connected to bow) b, Q, and d.

The oil pressure reaches the same place as in case D from bow) b and C, and the rear clutch 105 is engaged, while the lower part of the second lock valve 185 has no oil pressure in this case, and the circuit of the spool 178. Since the areas of the lands above and below the part that opens to 152 and where hydraulic pressure acts are larger at the bottom, the spool 178 of the second lock valve 185 is pushed down against the force of the spring 179, and the circuits 152 and 162 are brought into continuity. Then, the oil pressure reaches the engagement hydraulic chamber 16G of the servo 141, engages the second brake 106, and the transmission becomes the second forward gear position U-. From boat d, oil pressure passes through circuit 154 to solenoid downshift valve 187 and throttle backup valve 188.

There is a disconnect between the boat a of the speed selection valve 1.110 and the line pressure circuit 114, and the line pressure circuit 114 is disconnected from the circuit 151 to the 2-8 shift valve 18.
Since the M pressure has not reached 2, the second brake 106
104 is not engaged and the transmission is not in the 8th forward speed state, and the second lock valve 185 works together with the speed selection valve 130 to move the transmission into the 2nd forward speed state. It functions to keep it fixed. When the speed selection rod is moved to the work (first forward speed fixed) position, the line pressure circuit 1Φt is connected to boats c, d, and e. The oil pressure reaches the same place as in case ■ from bow) C and d, and the rear clutch 10
5, and from boat e, a circuit 165 passes through the 1-2 shift valve 131, a part of it goes from circuit 171 to the low reverse brake 107, and the low reverse brake 107, which functions as a forward reaction brake, is engaged. , put the transmission in the @ forward 1st gear state, and partially shift the 1-2 shift valve 181 to the left (
II], the spring 159 acts to keep the spool 160 pressed to the right, and the first forward speed is fixed.

As shown in FIG. 2, a lock-up mechanism 17 is provided in the torque converter 1, which is connected to a lock-up control valve 80 and a lock-up solenoid 81 shown in FIG.
The lock-up mechanism 17 and the lock-up control device 1 are controlled by a lock-up control device 100 consisting of
00 is well known and has no relation to the present invention, so its explanation will be omitted.

In the present invention, a shift shock reducing device 200 is provided as shown in FIG. 8 to reduce shift shock caused by 2→8 shift up. As is clear from the above, this upshift is performed by transmitting the line pressure PL from the oil m16B to the front clutch 104 to the front clutches (F, '
Since this is achieved by supplying the front clutch pressure P as P and activating (engaging) the front clutch, the 2→8 shift shock reducing device 200 is provided in connection with the oil passage 168 to control the front clutch pressure P in a predetermined manner.

As clearly shown in FIG. 4, such a shift shock reducing device includes an orifice 198 in the Δ The branch path 201 is connected to the drain boat 202, and the two connections are connected and disconnected by a solenoid valve 208.
3 is provided with a plunger 20ab elastically supported by a spring 208a in the valve closed position shown in the upper half of the figure, and when this plunger is electromagnetically attracted to the valve open position shown in the lower half of the figure by the urging of the solenoid 203C, Branch road 201 is drain boat 2
02.

The electric vμ valve 203 (solenoid 2030) is duty-controlled so that it is energized during the pulse width (on time) of the pulse signal from the computer 204 as shown in FIGS. 5(a) and 5(b). As shown in Fig. 5(a), when the duty (%) is small, the communication time between the branch passage 201 and the drain boat 202 is short, and therefore the front clutch pressure P is reduced by the solenoid duty as shown in Fig. 6. As the pressure decreases, it becomes higher and finally reaches the maximum value, which is equal to the original pressure, that is, the line pressure PL. Conversely, when the duty value is large as shown in FIG. 5(b), the branch path 201 and the drain port are
Therefore, as shown in FIG. 6, the front clutch pressure P decreases as the solenoid duty increases, and finally reaches the minimum value determined by the difference in the opening areas of the orifices 198 and 199.

The computer 20 for performing the above duty control is driven by the power supply +■, and receives a signal Sp1 from a pressure sensor 205 that detects the front clutch pressure P. A throttle opening sensor 20 that detects the engine throttle opening - FTH.
Signal STH% from 6 detects engine rotation speed NE Signal from engine rotation speed sensor 2θ7 Detects output rotation speed of torque converter 1 (rotation speed of turbine blade wheel 8 that transmits rotation to input shaft 7) NT Signal St from torque converter output rotation speed sensor 208
r 1K M Machine output rotation speed (output shaft 1
12) signal S from the transmission output rotation speed sensor 209 that detects No. rl and automatic transmission gear position (
Duty control of the electromagnetic valve 208 is performed based on the calculation results of a signal S8 from the shift switch 210 that detects the shift stage), the presence or absence of a shift, and the type of shift. As the shift switch 210, it is possible to use one constructed by being incorporated into the shift valve 181.1!12, as shown in, for example, Japanese Patent Laid-Open No. 56-127856.

A computer (Mp
U) 24, a read-only memory (ROM) 25,
It is composed of a microcomputer consisting of a human output interface circuit (Ilo) 22, an analog-to-digital (A/D) converter 27, a waveform shaping circuit 28, and an amplifier 29, and controls as shown in FIGS. 8 to 11. Assume that the program is executed.

FIG. 8 shows the main routine, in which the engine ignition switch is turned on at block 70, the computer 204 starts operating, and at the next block 71, the engine ignition switch is turned on and the computer 204 starts operating.
Initial value setting (initialization) of P U 24 and l1026 is performed. Next, the control proceeds to the program 72, where the throttle I use signal STH from the MPU 24G and the throttle opening sensor 206 is converted into a digital signal by the A/D converter 27 (however, in this example Assume that the digital signal is quantized by dividing the range from full throttle to full throttle into 8 parts)
28, and the throttle opening 1fTH is read. In the next block 78, the MPU 24 sends the pressure sensor 20
After converting the signal Sp from 5) into a digital signal by the A/D converter 7, it is read through I1026, and the front clutch pressure P is read.

Next, the control proceeds to block 74, where the MPU executes the interrupt routine r shown in FIG. Calculate. Sensor□2
07 detects the ignition signal of the engine and emits a signal Sir as shown in FIG. 9(b), and this signal is subjected to noise removal by the waveform shaper 28 as shown in FIG. 9(b). A rectangular wave signal S, / rises every time the ignition signal is input. Then, the MPUg4 starts the interrupt routine shown in FIG. 9(a) every time the signal Sir' rises.
First, in block SO, the rising edge of the signal "'ir" is detected as l10.
26, and the previous signal Si is read in the next block number l.
Measure the signal period TE from the time difference with the rise of r',
The MPU 24 can calculate the engine rotation speed NE from this period TE. Then i! Il starvation has 2 blocks
The program then returns to the main routine shown in FIG.

In the next block 75 in FIG. 8, from the engine rotation speed NE (NEW ) determined in block 71 and the engine rotation speed NE (oLD ) determined in block 74 in 1 loop ntf, the engine rotation during l calculation cycle is determined. Number change ΔN
E is calculated by ΔNE, =NE(OLD)-NE(NEW). Since the calculation cycle is constant, this ΔNE can be regarded as a time-varying force of the engine rotational speed. In the next block 76, the MPU 24 receives the signal "tr" from the sensor 208.
Based on this, the interrupt routine shown in FIG. 10(a) is executed as follows to calculate the output rotational speed NT of the torque converter 1. The sensor 208 is installed around the input shaft 7, and is a sine waveform generator that outputs the signal St1 shown in t10 (b) during its rotation. By triggering the shaper 28, the waveform shaper generates a rectangular wave shown in ) in FIG.
@Str'. And MPU 24 is a signal"
The interrupt routine shown in FIG. 10(a) is started every time 'tr' rises, and first, in block 50, the signal 'tr' is
o is read in red, and in the next block 51, the previous signal St
Measure the signal period T from the time difference between MPU2+
is the output rotation speed NT of the torque converter based on this cycle.
can be calculated. Thereafter, control proceeds to block 52, where the main routine of FIG. 8 is returned.0 In the next block 77 in FIG. rfr: Calculates the transmission output rotation speed No. Sensor 209 is similar to sensor 208 and is attached to output shaft 112. Therefore, the transmission output rotation speed N. When the PIJ 24 executes an interrupt routine similar to that shown in FIG. 10(a), the torque converter output rotational speed NT in block 16 can be calculated in the same manner as before.

In the next block 78, it is determined whether the shift determination determiner S0 is set to 1 or not. In this example, this shift determiner indicates that a 2→8 shift up is being performed to reduce the shift shock, and if S□=1, S□=0 during the shift.
If so, it indicates that the gear is being shifted or not being shifted otherwise.

If 80=1 during a 2→8 shift up, control returns to block 72 and repeats each of the execution blocks described above.
If 81←l is not in progress, the control proceeds to block 79.80 to check whether there is a new 2→8 shift up command. Therefore, the block 9 reads the shift signal S8 from the shift switch 210, and the next block 80 reads the shift signal S8 from 2→8 from this shift signal.
Check whether there is a shift command, that is, 2→8 shift valve 1B.
2 has been shifted to the upshift position to select the 8th speed.

If there is no 2→8 shift command, the control returns to block 72, and if there is a 2→8 shift command, the control proceeds to block 81, where the 2→8 shift command is changed at the instant t of the z→8 shift command, as shown in FIG. Set 80=1 to indicate that the gear is being shifted. In the next block 82, the engine rotation speed change (ΔNE) during one calculation cycle is used to determine the timing at which the front clutch 104 starts to be engaged (speed change start timing), which is the object of the present invention. Insert into the film. This change in engine speed (
ΔNE).

The reason why the shift start timing can be determined is that the engine rotation speed N at the shift start time t8, as shown in FIG. 1z. This is because the temperature starts to change suddenly. And (ΔNE). is different depending on the type of shift (2→8 shift in this case) and throttle opening, so it is stored in ROM5 as table data in advance.
and block 7 from this table data.
Based on the shift signal S8 (type of gear change) read in block 9 and the throttle opening TH read in block 72, the table look amplifier method is used. Note that after the break in step 82, the control system returns to step 72, and the above-described loop is repeated.

FIG. 11 shows an interrupt routine for performing the control aimed at by the present invention based on the execution results of the control 1 program shown in FIGS. 8 to 10. In block 88, a timer (
(not shown) is repeatedly executed by an interrupt signal input at every set time interval ΔTms. First, in block 84, it is determined whether or not the shift determination element S□ is 1 to determine whether or not this example is a 2->8 shift sequence targeted for shift shock reduction.

If so, control passes to block 85 and block 79
The gear ratio G (1 in this case) corresponding to the shift signal @ (gear position tl, (rj, 8th gear in this case) read in) is stored in the ROM.
25 and the transmission output rotation speed N obtained from this and block 77. Calculate the torque converter output rotation speed GXNo when the front clutch 104 is completely engaged using the samurai, and subtract this from the actual torque converter output rotation speed NT determined in block 76, that is, NT-G-N.
1,000 F is determined by the calculation of o to determine the end of the gear shift () completion of engagement of the four-wheel clutch 104.

If the front clutch 124 is firmly engaged after the shift has been completed, F=0, but if the front clutch 104 is not yet fully engaged in the first shift, F~0. Furthermore, when changing gears, the gear ratio G (large → small)
In the upshift that changes as F>0, the gear ratio G becomes (small→
In one downshift that changes to 0 (large), it becomes 0.

In block 86, it is determined whether the shift end determiner F is positive or negative, and F
) 0, that is, it is an upshift, the process proceeds to block 87, and since this amplifier shift is a 2→8 shift, this y
Block 87 is selected only for them. When this shift is completed, it should become F-0, but the torque converter output rotation speed NT and the transmission output rotation speed N. There is a possibility that F=O does not completely hold due to the deviation in the detection time and the calculation W error. Therefore, in block 87, when the absolute value IF+ of the shift end determiner F becomes less than or equal to the set minimum value ε□,
It is determined that the shift has been completed, and control proceeds to block 93, where 80 is reset to 0. On the other hand, IF1≦ε
In the case of □, that is, when shifting is in progress, control is switched to block 8.
Proceed to 8.

In block 88, front clutch ]04I's 6'[
It is determined whether or not a series start determiner S, which becomes 1 when the 2→3 series has already started due to the start of f-coupling and becomes 0 when this shift has not yet started, is 1. 82-1
If it is determined that the block 89 is a new 2->3-shift 15
It is determined whether or not there is a n beginning.

In making this determination, at the start of gear shifting (at t8 in Fig. 12)
) As mentioned above, since the engine speed change ΔNE in block 76 exceeds 1 (J1 judgment engine speed change (ΔNE)) at the start of the shift in block 82,
When this signal is detected, it is determined that the 2 to 8 shift has started due to the start of engagement of the front clutch 104.0 When the shift has started, the block 89 is set to the block 89'.
, read the front clutch pressure P0 at this time (see Fig. 12), and in the next block 90 calculate the front clutch pressure (clamping force of the front clutch 101) necessary to prevent the 2->8 shift shock with respect to the above pressure P. Correction value P. is read from the ROM25. This correction value P. is the shift signal S
The type of gear change determined by the above reading in step 8 (in this case, 2→
8 shifting) and throttle opening 1iTH read as above.
This data is stored in the ROM 25 in advance as table data, and read out using a table lookup method.

Note that in this example, the correction value P. is fixed at the read value, but it is also possible to gradually increase it as the shift progresses as long as shift shock does not occur.

In the next block 91, the standard value "aim" of the front clutch pressure that should be maintained to prevent shift shock is set to "aim ="
``□+Po'', then block 92 sets the shift start determiner S2 to S, = 1. Control then proceeds to block 96, or once 52 = 1 is set, block 88 sets block 96 to S, = 1. To select, then the following 2
→Blocks 89, 89' and 90 to 92 are not selected until the 8th gear shift.

In block 96, the actual value P of the front clutch pressure and the difference ΔP between the target pressure Pa1m are calculated, and in the next block 97, it is determined whether ΔP>0, and if ΔP)O, the difference P
) P aim, the control proceeds to block 99, where a calculation is performed to increase the output duty by - ΔP to Duty (NEW) = Duty (OLD) +, and the calculation result Duty (NEW) is applied to the next block 10'. Dut at 0
You can place it in y (OLD). and block 101
With Duty (NEW) as the output duty,
It is output to the solenoid valve 208 via the seventh amplifier 29.

Note that Duty (NEW) is the output duty to be newly updated, Dut'i' (OLI) is the current output duty, and the feedback coefficient is a constant value. Of course, it is also possible to make the feedback coefficient K a function of the pressure difference ΔN. As shown in Figure 6, as the output duty increases, the front clutch pressure decreases, so
By correcting P>Pa1111, it is possible to bring the front clutch pressure P closer to the eye P (pressure "aim").

On the other hand, if the determination result of block 97 is ΔP>0, that is, if P<Pa1m, control proceeds from block 96 to block 9B. Duty (NEW) in block 98
= Duty(OLD) -K-ΔP is calculated in the output duty decreasing direction, and as a result, Duty(NEW
) through the next blocks 100 and 101, and the above ΔP)
Similarly to the case of O, it is output to the solenoid valve 203. In this case as well, as shown in the sixth column, the front clutch pressure P is increased by reducing the output duty, and "<"a
Im is corrected to set the front clutch pressure P to the target pressure "ai"
It is possible to get close to m.

Thus, as shown in FIG. 12, the front clutch pressure P is maintained at the target value "aim" from the shift start instant t8 after the 2->3 consecutive shift command instant t until the shift end - time t.
The torque transmission capacity of the front clutch 104 can be kept constant. Therefore, when shifting from 2 to 8 gears, the rotational force combined with the engine's inertia and stiffness changes at a constant rate.
It will be transmitted to the machine output shaft, and the transmission output rotation speed N
. 12, the engine speed N8 can be changed as shown by the solid line in FIG. 12, and the transmission output shaft torque can be changed as shown by the solid line in the same figure, and these are respectively shown by the dotted line in the same figure. The peak torque T2 that occurred due to
(Explanation method with reference to FIG. 15('b)) It is possible to reliably reduce the 2→8 shift shock caused by the above.

In addition, in determining the target value "aim," the front clutch pressure P0 at the start of gear shifting is used as a reference, and the engine rotation speed N,
In order to obtain the torque transmission capacity of the front clutch 104+ necessary to reduce the torque at a predetermined time change rate required to prevent front speed shock, the above P process was set as a modified value P, and the corrected value was set as a target value Pa1m. , front clutch 1
Even if there are variations in the 04 product or changes over time, the target value can always be set to the optimal value without being affected by these, and without causing excessive slippage of the front clutch (early wear or power loss). Gear shift shock can be reliably prevented.

In the above example, the target value Pai was fixed during gear shifting, but as described above, P. By changing the
It is also possible to use aim as an initial value to shorten the speed change.

By the way, in FIG. 11, when the block 84 determines 81"r1, that is, when it determines that there is no 2→8 shift command, and when the block 86 determines Fku0, that is, F)0, the shift is a downshift. If it is determined that the above control is the object of the present invention, the control proceeds to block 94, similar to after execution of blowing 98, the shift start determiner Sg is reset to 0, and then Control passes to block 95.

In block 96, the output duty is set to 0%, and this output duty of 0% means that the front clutch pressure P is changed to the line pressure P1. In this case, the operation control of the front clutch 104 is left to the shift control hydraulic circuit shown in FIG. The execution of block 95 is executed by block 8
9 is ΔNF>(ΔNE). This is also carried out before the start of the shift (between t2 and t8 in FIG. 12) when it is determined that this is not the case.

The controller 1i11i then advances from the brick 95 or 101 to the brick 102, where it returns to the main routine of FIG. 8, and the above-described control is repeated.

FIG. 18 shows another example of the present invention, and this example is layered to reduce the shift shock caused by the 1->2 shift up. As is clear from the above, this shift amplifier transmission is carried out from the oil passage 162 to the second brake +
106) This is achieved by supplying the line pressure PL as the second brake operating pressure P to the engagement side oil passage 169 of the operating servo 141 and operating the second brake 106, so the shift shock reducing device 20 is similar to the example described above.
0 is provided in connection with the oil passage 162, thereby making it possible to control the second brake operating pressure P to a predetermined value.

For this purpose, the computer 204 executes the same control program as shown in FIGS. 8 to 11 in this example. Block 78 changes the front clutch pressure P to second brake operating pressure P, changes the shift determiner S0 in block 78.81 to indicate that there is an l→2 shift command, and changes the 2→8 shift command in block 80. The command is changed from 1 to 2 shift command, and block 82 changes the engine speed (ΔNE) to determine when to start applying the second brake (shifting). Change it to something that reads.

Also in FIG. 11, the shift determiner S0 in block 84.98 is changed to the same one as described above, and the shift start determiner S2 in block 88.92.94 is changed in response to the start of engagement of the second brake 106. It will be changed to indicate that the 1st → 2nd gear shift has started.

Thus, as shown in FIG. 14, from the shift start instant t8' after the shift command instant tl during the 1→2 shift, to the shift end instant t4'.
Until then, the second brake operating pressure P is kept at the target value "aim", and the torque transmission capacity of the second brake 106 can be kept constant. Therefore, when shifting from 1 to 2, the rotation of the engine inertia and driving force is the same. The force will be transmitted to the transmission output shaft at a constant rate, and its rotational speed N
. 141, the engine speed N8 can be changed as shown by the solid line in FIG. 141, and the transmission output shaft torque can be changed as shown by the solid line in the same figure, and these are as shown by the dotted line in the figure. The l→2 shift shock caused by the peak torque T0 (explained in FIG. 5(a)) can be reduced in the same way as the 2→3 shift shock.

In addition, since the target value "aim" is determined based on the second brake operating pressure P□ at the start of gear shifting, by correcting P. The target value can always be set to the optimum value without being changed, and the same effect as in the case of 2->8 shifting described above can be achieved.

Note that in all of the above examples, upshifting (2→
Although the present invention is configured to reduce the shift shock during downshift (8->2.2->1), the same concept can be used to reduce the shift shock during downshift (8->2.2->1). It goes without saying that these problems can be reliably reduced, and that effects similar to those described above can be achieved.

(6) Effects of the Invention Thus, as described above, the shift shock reducing device of the present invention determines the target working pressure Pa1m of the friction element 104 (106) necessary for preventing shift shock based on the working pressure P0 at the start of shifting. , that is, this P□ is a predetermined amount P. The value obtained by correcting the above is the target value.
aim is always at an appropriate value that takes these factors into account, and the target value is too high and the shift shock cannot be sufficiently reduced, or the target value is too low and there is a shift delay or power loss due to excessive slippage of the friction element. Problems such as losses and premature wear can be reliably eliminated.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram showing the shift shock reducing device of the present invention, Fig. 2 is a skeleton diagram showing the power transmission section of an automatic transmission equipped with the device of the present invention, and Fig. 8 is a shift control hydraulic circuit of the automatic transmission. ■, Fig. 4 is a system diagram of the device of the present invention, Fig. 5 (a) and Fig. 5 (b) are time charts showing changes in duty output by the computer of the device, respectively, and Fig. 6 is a diagram regarding the duty. Front clutch pressure change characteristic diagram, IJ7 Figure 7 Computer block diagram, Figure 8
9(a) and 10(a) are flowcharts of the control program executed by the computer, respectively. Figure 11 is a flowchart of a control program executed by a computer, Figure 12 is an operation time chart of the device of the present invention, and Figure 18 is a diagram showing another application example of the device of the present invention. The first figure is an operation time chart of the device of the present invention in the same application example, and the first figure is an operation time chart of the device of the present invention in the same application example.
It is an operation time chart showing the occurrence of shift shock during 3rd shift. 24... Microb four setter unit 26... Read-only memory 26... Input/output interface circuit 27... A/
D converter 28... Waveform shaping circuit 29... Amplifier 1041.106... Friction required q (104... Front clutch 106... Second brake) 198.199... Orifice 200... Pieces Invention shift shock reduction device 201...
Branch path 202...Drain port 208...Solenoid valve 204...Control computer 205...Pressure sensor (operating oil pressure detection means) 20
6...Throttle opening sensor 207...Engine speed sensor 20B...) switch. Figure 1 Figure 4 Figure 5 Figure 6 Zoshinoid Meichi? --T (%λ) Figure 12 Figure 13 Figure 14 Figure 15 (a) (b)

Claims (1)

[Claims] 1. Gears can be changed by hydraulic operation of selected friction elements,
In an automatic transmission comprising a hydraulic pressure control means for controlling the hydraulic pressure to a target value required for preventing shift shock during the operation of the friction element, the hydraulic pressure detecting means detects the hydraulic pressure of the friction element; a shift start detection means for detecting the start of operation of the friction element; and a target working oil pressure determining means for instructing the working oil pressure control means to set a value obtained by modifying the working oil pressure at the time of starting the operation of the friction element by a predetermined amount as the target value. A shift shock reducing device for an automatic transmission, characterized by comprising: λ The shift shock reducing device for an automatic transmission according to claim 1, wherein the target operating oil pressure determining means changes the predetermined amount according to the type of shift and the engine load.