JPS629779B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a transmission device used in a vehicle drive system, particularly a power transmission system between an engine and a driven member (drive wheel in the case of a vehicle) driven by the engine, which is capable of slip control. This invention relates to a transmission device in which a fluid coupling and a gear transmission mechanism are inserted.

A vehicle runs by changing the speed of the power from the engine using a gear transmission mechanism and transmitting it to the drive wheels.
Today, due to the rising cost of fuel, improving fuel efficiency has become an urgent need. Therefore, when a gear transmission mechanism is configured as an automatic transmission or a semi-automatic transmission, the input/output rotation difference (slip amount) of the fluid coupling (usually a torque converter) installed in the front or rear stage (usually the front stage) is vibrated. Fluid coupling slip control devices that control slippage to the minimum necessary level are now in practical use in some vehicles to reduce fuel consumption.

An example of the slip control device is the conventional slip control device
There were some such as those shown in Publication No. 57-12128 and Japanese Utility Model Application Publication No. 57-33253. However, since all of these conventional slip control devices maintain the slip amount of the fluid coupling constant at all times, they have not been able to achieve a reliable vibration suppression effect at all gear positions of the transmission.

In other words, the power train system that transmits engine power to the driving wheels is a multi-degree-of-freedom coupled vibration system, and when engine torque fluctuations are transmitted to this system as excitation force, the power train system vibrates together with the vehicle body.
The characteristics of the vibration system described above are that when the gear position of the transmission changes, the power transmission system changes, so the vibration level of the power transmission system and the vehicle body changes as shown in Figure 15. As the speed reduction ratio decreases to 3rd gear and OD (overdrive), there is a tendency to increase from α to β, and then from β to γ.

Therefore, in order to keep the amount of slip constant in conventional slip control devices, the level of vibration increases at the gear position of a transmission with a small reduction ratio, causing discomfort to the passenger, or when the gear position of a transmission with a large reduction ratio increases. However, the amount of slip is larger than necessary, resulting in the problem that the engine cannot achieve the desired fuel efficiency improvement effect.

In view of the above-mentioned circumstances, the present invention provides a slip control device for a fluid coupling for a transmission, which is configured to increase the slip amount of the fluid coupling as the gear position of a gear transmission mechanism becomes a high-speed gear position. It attempts to solve problems.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 shows an embodiment of the apparatus of the present invention, in which 1 is an engine, 2 is a crankshaft thereof, 3 is a flywheel, 4 is a torque converter as a fluid coupling, and 5 is a gear transmission mechanism. During its operation, the engine 1 moves the crankshaft 2 to the flywheel 3.
The torque converter 4 has a pump impeller (input element) 4a connected to the flank shaft 2 via the flywheel 3 and driven by the engine, a turbine runner (output element) 4b facing the pump impeller 4a, and a stator. (Reaction force element) 4c
The turbine runner 4b is drivingly connected to the input shaft 7 of the gear transmission mechanism 5, and the stator 4 is connected to the input shaft 7 of the gear transmission mechanism 5.
c is placed on a hollow fixed shaft 9 via a one-way clutch 8. The torque converter 4 supplies working fluid to its internal converter chamber 10 in the direction of arrow a, and removes this working fluid in the direction of arrow b, and also closes the converter chamber 1 by a pressure holding valve (not shown) provided in the middle.
0 is kept at a pressure (converter pressure) P _C below a certain value. Thus, as described above, the pump impeller 4a driven by the engine stirs the internal working fluid, causes it to collide with the turbine runner 4b, and then flows through the stator 4c, during which time the torque of the turbine runner 4b is increased under the reaction force of the stator 4c. Rotate while rotating.
Therefore, power from the engine 1 is transmitted to the drive wheels via the torque converter 4, input shaft 9, and transmission mechanism 5, allowing the vehicle to travel.

Further, the torque converter 4 is provided with a lock-up clutch 11 in order to achieve a slip control type that can control the slip (relative rotation between the input element 4a and the output element 4b), and this is provided with a torsional damper 12.
A lock-up chamber 13 is connected to the torque converter 4 separately from the converter chamber 10 so as to be drivingly coupled to the input shaft 9 via the input shaft and movable in the axial direction on the input shaft.
Set within. The lock-up clutch 11 moves to the left in the figure in response to the difference between the converter pressure P _C in the converter chamber 10 and the lock-up pressure P _L/u in the lock-up chamber 13, and applies a force corresponding to the differential pressure to the input/output elements. The slip of the torque converter 4 can be limited by drivingly coupling between 4a and 4b.

The lockup pressure P _L/u is adjusted by a slip control valve 14, which is connected to a port 14a communicating with the lockup chamber 13, a port 14b to which the converter pressure P _C is introduced, and a drain port 14.
c, when the spool 14d is in the neutral position shown in the drawing, the port 14a is cut off from both ports 14b and 14c, and when the spool 14d is moving to the right in the drawing, the port 1 is closed.
4a is connected to the port 14b, and when the spool 14d moves to the left in the figure, the port 14a is connected to the port 14c. The spool 14d responds to the differential pressure between the lock-up pressure P _L/u acting on the right end surface in the figure through the orifice 15 and the control pressure P _S acting on the left end surface in the figure, and the control pressure P _S is as follows. Build it like this. That is, one end 1 of the control pressure generation circuit 16
A reference pressure (line pressure in the case of an automatic transmission) P _L that controls the speed change of the transmission mechanism 5 is supplied from 6a, and this line pressure is drained from the other end 16b of the circuit 16 via orifices 17 and 18, and the drain By determining the amount by the duty-controlled solenoid valve 19, a control pressure P _S can be created between the orifices 17 and 18.

In the normal state, the solenoid valve 19 closes the drain opening end 16b of the circuit 16 by moving the plunger 19b to the left in the drawing by the spring 19a, and whenever the solenoid 19c is energized, the plunger 19b moves to the right in the drawing. position and open the drain opening 16b to allow the above-mentioned drain. The energization of the solenoid 19c is duty controlled such that it is carried out during the pulse width (on time) of the pulse signal from the slip control computer 20 as shown in FIGS. 2a and 2b. As shown in FIG. 2a, when the duty (%) is small, the time during which the solenoid valve 19 opens the drain opening 16b is short, and therefore the control pressure P _S is equal to the line pressure P _L as shown in FIG. 3. Also, duty (%)
As shown in FIG. 2b, the solenoid valve 19 begins to open the drain opening end 16b for a long time, and the control pressure P _S gradually decreases as shown in FIG. 3, and finally the orifice 17, It is a constant value determined by the difference in opening area of 18.

In FIG. 1, as the control pressure P _S increases, this control pressure moves the spool 14d to the right as shown in FIG _. P _L
/u = kP _S (where k is a constant), it gradually increases as shown in Fig. 5, and finally the converter pressure P _C
A constant value corresponding to As the control pressure P _S becomes lower, a lock-up pressure _P
/u moves the spool 14d to the left as shown in FIG. 4b to communicate the port 14a with the port 14c, and the lock-up pressure P _L/u gradually decreases in the same manner as above and finally reaches zero. Then, when the lock-up pressure P _L/u becomes a value corresponding to the control pressure P _S , the slip control valve 14 returns the spool _14d to the neutral position shown in FIG. This lock-up pressure can be controlled by a control pressure P _S .

By the way, the change characteristics of the control pressure P _S with respect to the duty (%) are as shown in Fig. 3, and this and the control pressure P _S - lockup pressure P _L shown in Fig. 5
_/u characteristic, the change characteristic of the lockup pressure P _L/u with respect to the duty size is as shown in FIG.

The slip control computer 20 receives the gear position signal S _C from the gear position sensor 6 that detects the gear position of the gear transmission mechanism 5 and the engine rotation speed (the rotation speed of the input element 4a) from the engine rotation speed sensor 21 using the power supply +V. It is operated in response to a signal S _ir , a signal S _pr regarding the rotation speed of the output element 4b (input shaft 9) from the torque converter output rotation speed sensor 22, and an engine throttle opening signal S _TH from the throttle opening sensor 23; Duty control of the magnetic opening valve 19 is performed.

For this purpose, the computer 20 is, for example, a seventh computer.
Microprocessor (MPU) 2 including random access memory (RAM) as shown in the figure
4, a read-only memory (ROM) 25, an input/output interface circuit (I/O) 26, an analog-to-digital (A/D) converter 27, a waveform shaping circuit 28, and an amplifier 29. It is assumed that the system is composed of a computer and executes the control programs shown in FIGS. 8 to 12.

FIG. 8 shows the main routine. When the engine ignition switch is turned on at block 80, the computer 20 starts operating, and at the next block 31, the initial values of the MPU 24 and I/O 26 are set (initialized). It is done. Next, the control proceeds to block 32, where the MPU 24 converts the throttle opening signal _STH from the throttle opening sensor 23 into a digital signal using the A/D converter 27 (however, in this example, the throttle opening signal STH from the throttle opening sensor 23 is It is assumed that the period up to full opening is divided into 8 parts and the digital signal is quantized), and the gear position signal S from the gear position sensor 6 is read through the I/O 26.
Read _C via I/O26. In addition, the signal S _C
For example, the gear transmission mechanism 5 is set to 2nd speed, 3rd speed, or
This indicates whether the OD gear position is selected, or whether 1st speed or reverse other than these is selected.

Control then passes to block 33 where the MPU
24 is a signal S _ir from the engine rotation speed sensor 21
Based on this, the interrupt routine shown in FIG. 9a is executed as follows to calculate the engine speed. The sensor 21 detects the ignition signal of the engine 1 and generates a signal S _ir as shown in FIG.
8 removes noise, resulting in a rectangular wave signal S _ir ' that rises every time an ignition signal is input, as shown in FIG. The MPU ₂₄ starts the interrupt routine shown in FIG _.
The previous signal S is read in the next block 41.
The signal period T ₁ is measured from the time difference with the rise of _ir ', and the MPU 24 can calculate the engine rotation speed from this period T ₁ . Control then proceeds to block 42 where the main routine of FIG. 8 is returned.

In the next block 34 in FIG. 8, the MPU 24 receives the signal S from the torque converter output rotation speed sensor 22.
Based on _pr , the interrupt routine shown in FIG. 10a is executed as shown below to calculate the output rotational speed of the torque converter 4. The sensor 22 is, for example, a sine waveform generator attached to the input shaft 9 and outputting a signal S _pr shown in FIG.
is triggered, and the waveform shaper generates a rectangular wave signal _Spr ' as shown in FIG. 10b. The MPU ₂₄ starts the _interrupt routine shown in FIG.
is read through the I/O, and in the next block 51, the signal period _T2 is measured from the time difference with the previous signal S _pr ', and the MPU 24 can calculate the output rotation speed of the torque converter 4 based on this period. can. Control then proceeds to block 52 where the main routine of FIG. 8 is returned.

In the next block 35 in FIG. 8, it is determined from the gear position signal _SC read in block 32 which gear position the gear transmission mechanism 5 is currently selecting. If the gear position is 2nd gear, block 36 is selected; if the gear position is 3rd gear, block 37 is selected;
If it is OD, block 38 is selected, and if it is 1st gear or reverse other than these, block 39 is selected.

In block 36, the MPU 24 retrieves from the ROM 25 a table corresponding to a torque converter slip amount diagram set to prevent the torque converter 4 from slipping too much while appropriately suppressing the vibration level in the second gear, as shown in FIG. 14a. The interrupt routine shown in FIG. 11 is executed based on this table, and the torque converter 4 is subjected to slip control as described later. In block 37, the MPU 24 reads from the ROM 25 a table corresponding to the third speed slip amount diagram shown in FIG. 4 is slip-controlled as described below. Also, MPU in block 38
24 reads from the ROM 25 a table corresponding to the OD slip amount diagram shown in FIG. Control slip. Furthermore, in block 39
Although not shown, the MPU 24 sets the slip amount of the torque converter 4 to the maximum in all engine speed ranges and all throttle opening ranges (complete A/
T) Read table O from ROM 25, execute the interrupt routine shown in FIG. 11 based on this table, and perform slip control on torque converter 4 as described later.

Fig. 14 a, b, c are respectively 2nd speed, 3rd speed,
The setting values for the slip amount (relative rotational speed between the input and output elements 4a and 4b) of the torque converter 4 during OD are shown, and these graphs show the vibration level at the corresponding gear position based on the engine rotational speed and throttle opening. It represents a suitable target slip amount of the torque converter 4 that should be achieved in relation to the above relationship.
Furthermore, complete A/T means lock-up clutch 11.
is a region in which no power is transmitted between the input/output elements 4a and 4b, and the torque converter 4 transmits engine power in a completely converter state (maximum torque converter slip amount), and in which the torque converter 4 transmits engine power in a complete converter state (maximum torque converter slip amount).
This means that the lockup clutch 11 is the input/output element 4.
This is a region where the torque converter 4 has a complete mechanical connection and the amount of slip of the torque converter 4 is zero.

As is clear from Fig. 14, 2nd and 3rd gear
When speed and OD are selected, when the engine speed is low and the throttle opening is large during high load operation, or when the throttle opening is set to the equivalent of idling, the engine torque fluctuations are large and the vibration level is high. Because of this, the torque converter 4 should be set to full A/
As the engine speed increases,
Torque converter 4 to reduce torque fluctuations
The slip amount is gradually decreased, and the slip amount is set so as to finally bring the torque converter 4 into the complete L/u state. As is clear from the comparison of Figure 14a, b, and c, the gear positions are 2nd speed and 3rd speed.
Since the vibration level tends to increase as shown in Fig. 15 as the speed shifts to high speed and OD, the target slip amount is set to be larger accordingly, although the pattern remains the same. In addition, the second
In gear positions other than 1st gear, 3rd gear, and OD, that is, 1st gear or reverse position, the torque increasing function of the torque converter 4 is required in the entire engine rotation range and the entire throttle opening range. The target slip amount is set to the maximum value so that the converter is in a complete converter state (complete A/T state) in all operating ranges.

Next, blocks 36 to 39 in FIG. 8 will explain the interrupt routine shown in FIG. (not shown) is started by an interrupt signal input at every set time interval ΔT _ns . First block 6
In step 1, the error between the target slip amount of the torque converter read from the table O, the table, or the corresponding address of the table based on the engine speed and throttle opening and the actually measured slip amount of the torque converter is measured. Next, the control proceeds to block 62, where a control calculation of the output duty value is performed based on the above error, and the next block 63 updates the output value, and then, at block 64, control returns to the main routine of FIG. Return.

Details of such an interrupt routine will be explained below with reference to FIG. That is, this routine is initiated by an interrupt signal input from the timer at set time intervals ΔT _ns at block 70, as described above with respect to FIG. First, in block 71, based on the throttle opening degree read in block 32 in FIG. Alternatively, it is determined from the corresponding address in the table whether the operating state of the engine 1 is in the lockup (complete L/U) region. If the engine is not completely in the L/U region, the control proceeds to block 72, where it is determined whether or not the operating state of the engine 1 is in the converter (complete A/T) region using the same table pickup method. /T region, that is, if the torque converter is in the slip region where slip control is to be performed, control proceeds to block 73. In block 73, the actual rotational difference between the two (torque converter output rotational speed) is determined from the engine rotational speed (rotational speed of input element 4a) and torque converter output rotational speed (rotational speed of output element 4b) calculated in blocks 33 and 34 in FIG. 4) is calculated. Next, the control proceeds to block 74, where the target slip amount read from the table O, the table, the table, or the corresponding address of the table by the same table lookup method as described above for blocks 71 and 72, and The error ΔN between the calculated actual measured slip amount is calculated.
In the next block 75, it is determined whether the error ΔN is ΔN≧0, that is, whether the measured slip amount is larger than the target slip amount and the torque converter 4 is slipping too much. If so, block 76 is selected, and here Duty (NEW) =
Duty (OLD) + K・ΔN is calculated in the direction of increasing the output duty, and the calculation result is Duty
(NEW) is replaced with Duty (OLD) in the next block 77, and then in block 78, Duty
(NEW) is output as an output duty to the solenoid 19c via the amplifier 29 in FIG. In addition,
Here, Duty (NEW) is the output duty to be newly updated, Duty (OLD) is the current output duty, and K is a proportional constant, so the above control adjusts the output duty by an amount proportional to the constant K according to the error ΔN. It will increase. Thus, in this case, as the duty is increased, the lock-up pressure P _L/u is reduced as is clear from FIG. 6, and the lock-up clutch 11 in FIG. As a result of strengthening the coupling, the excessive slip of the torque converter 4 is corrected, and the amount of slip can be brought closer to the target.

On the other hand, if the determination result of block 75 is not ΔN≧0, that is, if the torque converter 4 has insufficient slip, the control proceeds from block 75 to block 7.
Proceed to step 9. In block 79, Duty (NEW) =
Duty (OLD) - K・ΔN is calculated in the direction of decreasing the output duty, and the calculation result is Duty
(NEW) is output to the solenoid 19c through the next blocks 77 and 78 in the same manner as described above. Thus, in this case, by reducing the output duty, the lock-up pressure P is reduced, as is clear from FIG.
_L/u is raised, and the lock-up clutch 11 in FIG.
As a result of weakening the drive coupling between the torque converter 4b, the lack of slip in the torque converter 4 is corrected, and the amount of slip can be brought closer to the target.

After the interrupt routine ends, the control returns to the main routine shown in FIG.
The above program is repeated by returning control from block 32 (first speed, in reverse) to block 32.
Therefore, the slip amount ΔN of the torque converter 4 is controlled to approach the target slip amount _{S n as} shown in FIG. The second
It is possible to control to the set target value as shown in FIG. 14 when in 1st speed, 3rd speed, and OD, and to the maximum target value when in 1st speed and reverse.

If it is determined at block 71 in the interrupt routine of FIG. 12 that the operating state of the engine 1 is in the complete L/u region, control proceeds to block 81. In this block, the output duty is set to 100% of the maximum and output from the solenoid 19c via the amplifier 29 in Fig. 7. As a result, as is clear from Fig. 6, the lockup pressure P _L/u is minimized and the torque converter 4 can be placed in a lockup state where the input/output elements 4a and 4b are completely coupled (slip amount is zero) by the lockup clutch 11 as required.

If it is determined in block 72 that the operating state of the engine 1 is in the full A/T range, the control proceeds from block 72 to block 82, where the output duty is set to the lowest 0%.
As a result, as is clear from FIG. 6, the lock-up pressure P _L/u is brought to the same maximum value as the converter pressure P _C , and the lock-up clutch 11 is cut off, so that the torque converter 4 transmits power in the converter state as required. can be done.

In these cases as well, the control returns from block 81 or 82 to block 80 and returns to the main routine shown in FIG. 8, and by repeatedly executing the control program described above, the torque converter 4 can be subjected to slip control in the same manner as described above. .

Thus, for example, the slip control device of the present invention is configured to increase the slip amount of the fluid coupling 4 as the gear position of the gear transmission mechanism 5 becomes a high-speed gear position, so that it can correspond to the vibration level for each selected gear position. The slip amount of the fluid coupling can be set, and it is possible to reliably eliminate the inconvenience that the slip amount is insufficient at any gear position and causes vibration, or that the slip amount is excessive and worsens engine fuel efficiency. .

In addition, in the above example, the slips for 2nd speed, 3rd speed, and OD are set individually as shown in Figure 14 a, b, and c, and the corresponding tables are set.
The target slip amount was stored in the ROM 25 and read out from the ROM 25 individually using the table pull-up method at the relevant gear position, but as is clear from the comparison of Fig. 14 a, b, and c, the patterns are almost the same. is sequentially shifted toward higher engine speeds as the gear position increases.
ROM any one table or only
25, and add or subtract a certain value from the read slip amount for each gear position to obtain the target slip amount, or calculate the slip amount from the value obtained by adding or subtracting a certain value from the actual engine speed for each gear position.
Needless to say, it is also possible to read the amount from the ROM 25 and use it as the target slip amount.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing the power transmission system and slip control system of a vehicle equipped with the slip control device of the present invention, and Figs. 2a and 2b show changes in the duty output from the slip control computer, respectively. Fig. 3 is a change characteristic diagram of control pressure with respect to duty, Fig. 4 a and Fig. 4 b
5 is an explanatory diagram of the operation of the slip control valve, FIG. 5 is a characteristic diagram of changes in lockup pressure with respect to control pressure, FIG. 6 is a characteristic diagram of changes in lockup pressure with respect to duty, FIG. 7 is a block diagram of a computer for slip control, and FIG. Figure 8, Figure 9a, Figure 10a, 1st
1 and 12 are flowcharts showing the control program of the slip control computer, FIGS. 9b and 10b are waveform explanatory diagrams of the engine rotational speed signal and torque converter output rotational speed signal, respectively, and FIG. 13 14 is an operation time chart of slip control by the device of the present invention, FIGS. 14a, b, and c are torque converter setting slip amount diagrams when the transmission selects 2nd speed, 3rd speed, and OD, respectively. The figure is a vibration level diagram for each gear position of the transmission. 1...Engine, 2...Crankshaft, 3
... Flywheel, 4 ... Torque converter (fluid coupling), 5 ... Gear transmission mechanism, 6 ... Gear position sensor, 7 ... Transmission input shaft, 11 ... Lock-up clutch, 12 ... Torsion damper ,1
4... Slip control valve, 16... Control pressure generation circuit, 17, 18... Orifice, 19... Solenoid valve, 20... Slip control computer, 21
...Engine speed sensor, 22...Torque converter output speed sensor, 23...Throttle opening sensor, 24...Microprocessor, 25...
...read-only memory, 26...input/output interface circuit, 27...A/D converter, 28...waveform shaper, 29...amplifier.

Claims (1)

[Claims] 1. In a transmission device in which a slip-controllable fluid coupling and a gear transmission mechanism are inserted into a power transmission system between an engine and a driven member driven by the engine, the amount of slip of the fluid coupling is determined by the gear position of the gear transmission mechanism. 1. A slip control device for a fluid coupling for a transmission, characterized in that the slip control device increases as the gear position increases.