JPS59217056A - Lock-up controller for torque converter - Google Patents

Abstract

PURPOSE:To sufficiently reduce lock-up shock by gradually reducing the relative revolution between input and output elements at a prescribed ratio and controlling a clutch so that the relative revolution becomes zero, when a torque converter is transferred to lock-up state. CONSTITUTION:A power-source operation state monitor means 5 which detects that a power source 1 is in the operation state or not where lock-up is to be performed by the operation of a clutch 4 and a ship amount detecting means 6 for detecting the relative revolution between input and output elements 2 and 3 are arranged, and the outputs supplied from the both means 5 and 6 are input into a clutch control means 7, and the relative revolution between the input and output means 2 and 3 is gradually reduced at a prescribed ratio, and the operation of the clutch 4 is feedback-controlled so that the relative revolution becomes zero. Thus, when a torque converter is locked-up, shock can be reduced sufficiently.

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a torque converter used by being inserted into a power transmission system such as an automatic transmission for a vehicle, and in particular to a torque converter that can appropriately reduce the relative rotation (slip) between its input and output elements to zero and lock it up. This invention relates to a lock-up control device that aims to reduce shock when a torque converter is pulled up.

Conventional torque converters transfer power between their input and output elements via hydraulic oil and have a torque increasing function and a torque fluctuation absorption function, but on the other hand, relative rotation (slip) between input and output elements cannot be avoided. Power transmission efficiency is poor. Therefore, in places where the above-mentioned torque increasing function and torque fluctuation absorbing function are not required, some torque converters that can be directly connected and locked up to prevent relative rotation between input and output elements have already been put into practical use.

This type of torque converter generally includes an input element driven by a power source and an output element driven by hydraulic oil stirred by the input element, and the relative rotation between the input and output elements is reduced to zero by appropriate clutch operation. It is normal to connect directly so that it can be used as a four-quad amplifier.

The clutch is normally deactivated when the lock-up pressure supplied to it is made equal to the internal pressure of the torque converter (Fumbater pressure), and the torque converter is operated in a converter state where input and output elements are not directly connected, eliminating the lock-up pressure. When the torque converter is activated by the converter pressure, it functions to operate the torque converter in a lock-up state where the input and output elements are directly connected.

By the way, if the lock-up pressure is rapidly removed, the operating speed of the clutch in response to this also becomes faster, and a shock occurs when the torque converter locks up due to the clutch operation. For this reason, the lock-up pressure is usually removed through an orifice so that the lock-up pressure is removed gradually, but the reality is that even with this, the problem has not been solved.

That is, when the converter command is switched to the lock-up command at instant t1 in FIG. 10, the lock-up pressure decreases from a value equivalent to the converter pressure as shown in FIG. 1θ, and finally reaches zero. During this period, the clutch begins to engage at instant t2, one hour after the lock-up pressure reaches a value, and almost completes engagement at instant t8, changing the torque converter from the converter state to the lock-up state. Since the lock-up pressure is eliminated through the orifice, the lock-up pressure has a characteristic uniquely determined by its value and the opening area of the orifice.
As shown in the θ diagram, it decreases in a quadratic curve, temporarily from t2 to t8.
During this period, the P pull-up pressure decreases too quickly, and the torque waveform of the torque converter output shaft has a peak torque α when the clutch is engaged. Therefore, even if the torque converter is provided with an ori-ice as in the prior art, it has not been possible to sufficiently reduce the shock when the torque converter switches to the lock-up state.

Purpose of the Invention The present invention provides a structure in which the operation of the clutch is feedback-controlled so that the relative rotation of the input/output elements at this time is uniformly and gradually reduced at a predetermined ratio to zero when a lock-up command is issued. It is an object of the present invention to provide a lock-up control device embodying this idea, from the viewpoint that the lock-up shock of the torque converter can be sufficiently reduced and the above-mentioned intercondylar problem can be solved.

Structure of the Invention For this purpose, the device of the present invention has an input element 2 driven by a power source 1 and an output element 3 driven by hydraulic oil stirred by the power source 1, as shown in FIG. Ingredients,
In a torque converter that can be turned up by four by directly connecting the input and output elements 2 and 8 so that the relative rotation becomes zero by appropriately operating the clutch 4, the power? power source operating state monitoring means 5 for detecting whether or not jp, 1 is in an operating state in which p-tuck-up should be performed by actuation of clutch 4; and slip amount detecting means for detecting relative rotation between blade elements 2 and 3. 6, and a clutch control means 7 for feedback controlling the operation of the clutch 4 so as to gradually reduce the relative rotation at a predetermined ratio to zero in response to a lock-up command from the power source operating state monitoring means 5. shall be.

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

FIG. 2 shows the device of the present invention together with a torque converter to be subjected to lock-up control. It is a square axis.

During operation of the engine 1o, the crankshaft 11 is rotating together with the flywheel 12, and the -lux converter 1
A pump impeller (8) is drive-coupled to the crankshaft 11 via a flywheel 12 and is constantly driven by the engine.
It is composed of three elements: an input element) 18a, a turbine launch (output element) 18b opposed thereto, and a stator (reaction force element) 1aO.
The stator 180 is placed on the hollow fixed shaft 16 via the one-way clutch 15. The torque converter 18 is supplied with the working fluid from the pump 17 to its internal converter chamber 18d through the supply path for one day, returns this working fluid to the reservoir 20 through the return path 19, and is also supplied with the working fluid by the radiator 21 provided on the way. Cooling. Note that a pressure holding valve (not shown) is inserted in the return path 19, so that the pressure within the converter chamber 18d (converter EE) p is below the value.
Keep it at c. Thus, as described above, the pump impeller 18a driven by the engine stirs the internal working fluid, causes it to collide with the turbine runner x8b, and then flows through the stator 180, during which time the turbine runner 18b is torqued under the reaction force of the stator 18C. Rotate while increasing. The torque converter 18 during operation in such a funverter state can transmit the power of the engine 10 to the output shaft 14 while suppressing vibration and increasing torque while generating slip (relative rotation) between the input and output elements 18aj and 18ab.

The torque converter 18 further includes a clutch (ronoqua-amp clutch) 22 in order to perform a slip control type and a lock-up type that can limit and stop the above-mentioned slip.
This is drive-coupled to the output shaft 14 via a torsional hinge 28, and is movable in the axial direction on this shaft to define the lock-up chamber 24. The clutch 22 moves to the left in the figure in response to the lock-up pressure P L/u in the lock-up chamber 24 and the pressure difference between this and the converter pressure PO in the converter chamber 13d, and inputs and outputs with a force according to this differential pressure. Element 1
8a.

13b, it is possible to limit and stop slippage of the motor 18 under increased torque.

The lock-up pressure pI, /uGi slip control valve 26
For this purpose, the lock-up chamber 24 communicates with the bow 25a of the slip control valve 25 via a hollow hole in the shaft 14 and a circuit 26, as will be described later. The valve 25 is separately provided with a boat 25b to which the converter pressure PC is guided by a circuit 27, and a drain boat 25C, and when the spool 25d is at the neutral position shown, the boat 25a is connected to both boats.
25b.

250, and when the spool 25a moves to the left in the figure, the boat 25a is connected to the boat 25b, and when the spool 25 (1) moves to the right in the figure, the boat 25a is connected to the boat 250.

The spool 25d receives a converter pressure p that acts on the pressure receiving area difference of the spool lands in the chamber 25e.

the force exerted by the lock-up pressure PL/u acting on the pressure-receiving area difference of the spool land in the chamber 25f, and the control pressure p acting on the left end surface of the spool in the chamber 25g.
In response to the force exerted by s, the control pressure PB is generated by the control pressure generation circuit 28 and the solenoid valve 29 as follows.

That is, the reference pressure (for example, line pressure in the case of an automatic transmission) PL is supplied to the control pressure generation circuit 28 from one end 28a thereof,
This line pressure is connected to the circuit 28 through Oriais 28028d.
It drains from the other end 28b. By determining this drain amount by the duty-controlled electromagnetic valve 29, a control pressure ps can be created between the orifice 28C128 (1), and this is guided to the chamber 25g by the circuit 80.

The solenoid valve 29 includes a plunger 29a and a solenoid 29b that moves the plunger 29a to the left in the figure when energized.
When the power is reduced, the plunger 29a is pushed away by the drain working fluid from the drain opening end 28b, allowing the above drain, and the energization (energization) of the solenoid 2Qb achieves the lock-up of the torque converter, which is the object of the present invention. Duty control is performed so that the operation is repeated during the pulse width (on time) of the pulse signal as shown in FIGS. 8(a) and 8(b) from the slip control computer 81 which also performs control. Therefore, as shown in FIG. 8(a), when the duty (%) is small, the solenoid valve 29 closes to the drain opening end.
The time for closing 8b is short, so the control pressure ps becomes a constant value determined only by the difference in pressure receiving area of the orifices 280 and 28d, as shown in FIG. Duty (regret) is shown in Figure 8 (b)
), the solenoid valve 27 closes the drain opening end 28b for a long time, and therefore the control pressure p
s gradually increases as shown in FIG. 4 and finally becomes equal to the line pressure PL.

In FIG. 2, as the control pressure ps increases, this control pressure causes the spool 25d to move to the right as shown in FIG.
Lockup pressure PL/u decreases. On the other hand, as the control force Ps decreases, the spool z
5d is moved to the left as shown in FIG.
L/u increases. By the way, since the control pressure ps increases as the duty (qb) increases as shown in Fig. 4, the lock-up pressure "L/u" is equal to the converter pressure PO in the region of small duty (%) as shown in Fig. 6. As the duty (chi) increases, it decreases and finally changes to zero.

The slip control computer 81 is operated by the power supply +V, and detects the engine rotation speed sensor 88 or the rough engine rotation speed (the rotation speed of the input element 18a) Sir.

Shaft 14 from torque converter output rotation speed sensor 84 (
The duty control of the electromagnetic valve 2111 is performed as described below in response to the signal Sor regarding the rotation speed of the output element 18b) and the engine throttle opening signal STH from the throttle opening sensor 85. For this purpose, the computer 81 is a microcomputer as shown in FIG.
OM) 87 and input/output interface circuit (110)
a s and an A/D converter 89.

This microcomputer inputs the signals Sir and Sor from the sensors 88° and 84 after being waveform-shaped by the waveform shaping circuit 4o, and also converts the signal 8T from the sensor 85 into a digital signal by the A/D converter 89. The Ntt# program shown in FIG. 8 is executed based on these input signals to control the electromagnetic valve solenoid 29b via the amplifier 41.

FIG. 8 shows an interrupt routine, in which the following arithmetic processing is performed every time an interrupt signal is received at every partial time interval ΔT from a timer (not shown) in step 5°, and the torque converter 18 is switched to the slip state shown in FIG. 11, for example. Slip control is performed according to the dose diagram. FIG. 11 shows the rotational speed and throttle opening of the engine 1o, that is, the target slip amount of the torque converter 18 that should be achieved for each operating state of the engine 1o. Here, complete A/T means that the clutch 22 is completely disengaged. The torque converter 18 is activated and the input/output elements 18a,
This is the area where power transmission should be performed in the converter state (maximum slip amount) where the lab is not directly connected, and it is also a complete L/. means that the clutch 22 is fully activated and the torque converter 1
8 is a region where power is transmitted in the i-tuck-up state (zero slip state) in which the input/output elements 18 at 18 b are directly connected, and in addition, in regions other than these, the clutch 22 is operated in a half-clutch state and the engagement method is determined. The slip amount of the torque converter 18 (input/output element 1tla.

18b (Q relative rotation) IORPM, 2oRPMs4O
RPM, which is the slip area that should be 60 RPM. As shown by the arrow in this figure, when the torque converter 18 enters the complete L/U region from the "complete" region or the slip region, the torque converter 18 generates the above-mentioned P gear shift. to control the torque converter.

First, in step 51 of FIG.
The engine speed signal S is stored in the ROM 87 and is based on the table data corresponding to the slip amount diagram in FIG.
Based on ir and throttle opening signal STH, engine 1
0 completely connects the torque converter 18 to A7. Determine whether or not the operating state should be in the range 6. If so, the control proceeds to step 52, where the MPU 86 sets the output duty to 0, and in the next step 55' resets a counter to be described later. Set count @M to 0. Due to this duty zero check, as is not clear from Fig. 6, the p pull-up pressure PL/11
is set to the same maximum value as the converter pressure pc, and as a result of releasing the P pull-up clutch 22, the torque converter 18 is brought into the converter state as required in the full A/T region in FIG. 11, and power is transmitted in this state. be able to.

complete”/, if not the area, step 51 is step 5
3, and here, the MPU 86 selects engine rotation speed signal Sir and throttle opening signal 5Tl from table data corresponding to the slip amount diagram in FIG. If not, that is, if the engine 10 is in an operating state (slip region) in which the torque converter 13 should be subjected to slip control, control proceeds to step 54, where the MPU 86 executes a normal slip control program as follows: First, the MP
U86 sets a target slip amount of 10 RPM, 2 based on the engine rotation speed signal Sir and throttle opening signal ST■ from the table data corresponding to the slip amount diagram in FIG.
0 RPM, 40 RPM, or 60 RPM is read out using a table lookup method, and the coupling force of the clutch 22 is adjusted by controlling the duty of the solenoid valve 29 so that the slip amount of the torque converter 18 (relative rotation of the input/output elements 13a, 18b) becomes the target slip amount. Control. Thus, the torque converter 18 maintains the target slip amount of 10 RPM and 20 RPM for each operating state of the engine 10 in the slip region shown in FIG.
PM, 4ORPM, or 60RPM, and can operate with high power transmission efficiency while absorbing engine torque fluctuations in a slip state with just the right amount. After that, the control proceeds to step 55, where the MPUa6 also resets a counter, which will be described later, so that the count value M becomes zero.

By the way, when the operating state of the engine 10 changes from the above-mentioned complete A/T region or slip region to enter the complete L/u region as indicated by the arrow in FIG. 11, step 58 selects step 56, and here PU86 is step 55
' or 55, it is determined whether the count value K of the counter reset is greater than or equal to the set value Hmax. This counter is incremented by 1 every time it is activated as described below, that is, every time an interrupt signal is input from the timer (input every 41 hours), and serves as a timer for setting the time for performing the lock-up control of the present invention. , the relevant time is ΔT x M
Set by max. However, as a result of the above-mentioned reset, it is now the end and M=O, so the control proceeds from step 56 to step 57, where the MPU 86 outputs the signals Sir,
Based on Sor, calculate the actual rotational difference (torque converter slip amount) ΔN between the input and output elements by calculating 1 engine rotation speed (rotation speed of input element 13a) - output rotation speed (rotation speed 1 of output element 18b), Then in step 58 M=
Determine whether it is 0 or not.

As mentioned above, since M=O now, the control goes to step 59.
．． 60, and in these steps, the initial value ΔNi of the rotational difference (slip amount) and the initial value Duty at the start of the lock-up control according to the present invention are set.
Set (OLD)i. Next, control is step 6
1, and here the counter is activated to advance the count value M by one, and set it to M+1. This results in M\0, and after that step 58 selects step 61, and the count value of the counter is simply incremented by one.

Next, the control proceeds from step 61 to step 62, where ΔNi is determined from the above-mentioned initial rotational difference ΔN and count value M.
-AXM (where A is a constant) calculates the target slip amount of 2 doors reduced by one step, and in the next step 68, the deviation ΔX between the actual slip amount ΔN in step 57 and the target slip amount of 2 doors is calculated. In this example, as mentioned above, it is assumed that the target slip amount of 2 units decreases at a constant rate of change A over time, but with Plugram's ingenuity, an arbitrary functional form with respect to time ΔN" = f (t)
It can also be set to .

Next, the control proceeds to step 64, where it is determined whether the deviation ΔX is greater than 0, that is, whether the torque converter 18 is slipping too much with respect to the target slip amount ΔN. If so, step 65 is selected, where Duty (NE W ) ='Duty (O
L D ) Perform a calculation in the direction of increasing the output duty of 10K・ΔX, and the calculation result Duty (NE W )
is replaced with Duty (OL D ) in the next step 66, and then replaced with Duty (N E
W) is output as an output duty to the electromagnetic valve solenoid 29b via the amplifier 41 in FIG. Here, D
duty (NEW) is the output duty to be newly updated, Duty (OLD) is the current output duty, K.

Since is a proportional constant, the above control increases the output duty by an amount proportional to the constant K according to the deviation ΔX. As is clear from FIG. 6, due to this increase in output duty, the lock-up pressure PL/u is lowered, and the clutch 22 in FIG.
The excessive slip in the evening can be compensated for by 1, and the amount of slip can be brought closer to the target value Δdoor.

On the other hand, if the determination result in step 64 is not Δ×>0,
That is, if the torque converter 13 has insufficient slip compared to the target slip amount of 2, the control proceeds from step 64 to step 68. Here, the Duty (NE W
) = Duty (OLD) -K ・ΔX in the direction of decreasing the output duty is calculated, and the calculation result Duty (NEW) is used in the next step 6667
In the same way as described above, it is output to the electromagnetic valve solenoid 29b as an output duty. Therefore, the output duty is the deviation ΔX
Accordingly, the lock-up pressure PVu decreases by an amount proportional to the constant K, and as a result, as is clear from FIG.
is upper bounded, the clutch 22 in FIG. 2 weakens the coupling force, compensates for the lack of slip in the torque converter, and brings the amount of slip closer to the target value ΔN*.

The above control program is based on the time interval ΔT from the timer.
The slip amount ΔN of the torque converter 18 is controlled in stages to become the target slip amount ΔN* that is corrected at every ΔT time interval ΔT, and gradually decreases at a predetermined ratio, and finally It can be made zero.

That is, as shown in FIG. 9, the lock-up command is issued, and after the instant t1 when the control command according to the present invention is issued, the slip amount of the torque converter 18 finally reaches zero along the target slip amount □゛・. The output duty is changed so that this slip lid change is obtained. This frontage pull-up pressure PLl/u also changes as shown in FIG.
L/u can be kept almost flat. Therefore, the torque waveform of the torque converter output shaft only produces a small peak torque β near the instant t8, and lock-up shock can be almost eliminated.

When the lock-up control of the present invention is completed, the instantaneous tl
The instant t at which the set time ΔT x Mmax elapses from
4, the determination result of step 56 is M > Mm
ax, the control proceeds from here to step 69. In this step, the duty is set to 100%, and as a result of supplying this to the solenoid valve solenoid 29b, the sixth
As is clear from the figure, the four-up pressure PL/u is minimized and the torque converter 18 can be kept in lock-up as required in the full L/u region of FIG. 11.

Effects of the Invention Thus, the device of the present invention has a torque converter 1 as described above.
8 from the converter state or slip control state to the lockup state, the input/output element 2.8 (1
Since the configuration is configured such that the operation of the clutch 4 (22) is feedback-controlled so that the relative rotation of the clutches 8a and 18b) is gradually reduced at a predetermined ratio to zero, the lock-up shock can be made sufficiently small as described above with reference to FIG. It has the advantage of being able to

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing the device of the present invention, and Fig. 2 is a system diagram showing an embodiment of the device of the present invention. Figure 4 is a time chart showing the changes in duty output by the control computer; Figure 4 is a characteristic diagram of changes in control pressure with respect to duty; Figures 5 (a) and 5 (b) are diagrams explaining the operation of the slip control valve; Fig. 6 is a characteristic diagram of changes in lock-up pressure with respect to duty, Fig. 7 is a block diagram of the slip control computer, Fig. 8 is a flowchart showing the control AL program of the slip control computer, and Fig. 9 is a diagram of the control al program of the slip control computer. FIG. 10 is an operation time chart of the conventional device, and FIG. 11 is a slip amount diagram of the torque converter. ■...Power source 2...Torque converter input element, 8...Output element, 4...
- Clutch 5 - Power source operating state motor means 6... Slip amount detection means 7...
・Clutch control means 10...Engine (power source) 1
1... Crankshaft 12... Flywheel 1
3... Torque converter Hla... Doujinshi element 1
8b...Same output element 14...Torque controller (
- Output shaft 22...Clutch 24
... Four-up chamber 25 ... Slip control valve 2
8... Control pressure generation circuit 29... Solenoid valve 31...
- Slip control computer 38...Engine speed sensor 34...Torque converter output speed sensor 85...
・Engine throttle opening sensor 86...Microprocessor unit 37...Read-only memory 88...I/O interface circuit 89..."/
Converter 40...Waveform shaping circuit 41...Amplifier. Figure 3 Figure 4 Solenoid (%) Figure 5 (a) (b) Figure 6! Rolling ship, -chii (olo) Figure 9 Seal O

Claims (1)

[Claims] an input element driven by one power source, and an output element driven by hydraulic oil stirred by the input element,
In a torque converter capable of locking up by directly coupling the input/output elements so that relative rotation becomes zero by actuating a clutch as appropriate, detecting whether or not the power source is in an operating state in which lock-up should be performed by actuating the clutch. a power source operating state monitoring means; a slip amount detecting means for detecting the relative rotation between the input and output elements; and a slip amount detecting means for detecting the relative rotation between the input and output elements; 1. A four-up control device for a torque converter, comprising a clutch control means for feedback controlling the operation of the clutch so as to make the operation of the clutch zero.