JP2992039B2 - Lock-up clutch operation control device - Google Patents

Description

The present invention relates to a lock-up clutch operation control device applied to a fluid transmission device such as an automatic transmission for a vehicle.

2. Description of the Related Art Conventionally, as an operation control device for a lock-up clutch, for example, a device described in Japanese Patent Application Laid-Open No. 59-217056 is known.

According to this conventional source, a duty solenoid valve is used as a hydraulic control actuator to prevent a lock-up shock that occurs when the lock-up release pressure is removed and the lock-up release state is changed from the lock-up release state to the complete lock-up state at once. And a lock-up control valve for performing slip lock-up control by feedback control while monitoring the amount of slip between input and output elements, and thereafter performing control to shift to a complete lock-up state.

(Problems to be Solved by the Invention) However, in such a conventional work control device for a lock-up clutch, the lock-up control valve controls only the lock-up release pressure so that the lock-up apply pressure can be reduced. Because the differential pressure is created in the AT control unit, even if the lock-up duty output constant that provides the desired lock-up release pressure is input to the AT control unit in advance, the intended slip due to the variation or fluctuation of the lock-up apply pressure. A state may not be created, and a shock may occur due to an excessive fastening force, or a shock may occur when shifting from a slip lockup state to a complete lockup state due to an insufficient fastening force.

That is, the lock-up apply pressure causes individual variations due to variations in the mass-produced duty solenoid valves, dimensional variations of the lock-up control valve, and the like, and fluctuates due to changes in line pressure and oil temperature. Managing and fluctuating management increases costs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problem. In a lock-up clutch operation control device applied to a fluid transmission, a desired slip lock-up state is achieved while allowing a variation in lock-up apply pressure. And complete lock-up state easily, while at the same time ensuring reliable engine start by releasing lock-up during valve stick and ensuring complete lock-up with zero control pressure,
It is an object to achieve high-precision control as well as downsizing of a solenoid valve.

(Means for Solving the Problems) In order to solve the above problems, in a lock-up clutch operation control device of the present invention, an input element driven by a drive source, an output element driven via hydraulic oil, A fluid transmission device having a lock-up clutch capable of directly connecting the input / output element; and a differential pressure control for controlling a differential pressure between a lock-up apply pressure chamber and a lock-up release pressure chamber formed with the lock-up clutch interposed therebetween. In a lock-up clutch operation control device provided with a lock-up control valve as a means, the lock-up control valve has a configuration including a valve hole, a spool, and a spring, and the valve hole includes a torque converter pressure port and a pilot pressure. Port, apply pressure port, release pressure port and control pressure port The spool position where the spring is fully extended is the lock-up release position, and the torque converter pressure is the base pressure of the lock-up apply pressure and the lock-up release pressure created by the lock-up control valve, and the pilot pressure is a constant pressure. The pressure is supplied to the solenoid valve as a base pressure to generate the control pressure, and the force of the pilot pressure acts on the spool of the lock-up control valve to oppose the spring force. Acting on the spool of the lock-up control valve, the force of the lock-up apply pressure acts on the spool of the lock-up control valve to assist the spring force, and opposes the lock-up release pressure and the pilot pressure. Made in In addition to the relationship between the forces, the control pressure from the solenoid valve assists the spring force, and by controlling this control pressure, the spool is moved to control the differential pressure between the lock-up apply pressure and the lock-up release pressure. It is characterized by things.

(Operation) At the time of slip lock-up, a target differential pressure for obtaining a desired slip lock-up state is set in the lock-up control valve, and the lock-up apply pressure chamber and the lock-up release pressure are adjusted so as to match the target differential pressure. The differential pressure with the chamber is controlled by the control pressure.

Similarly, at the time of complete lock-up, a target differential pressure for obtaining a desired complete lock-up state is set in the lock-up control valve, and the lock-up apply pressure chamber and the lock-up release pressure chamber are adjusted to match the target differential pressure. Is controlled by the control pressure.

Therefore, even if there is variation or fluctuation in the lock-up apply pressure, this variation or fluctuation is tolerably absorbed by the differential pressure control, and without performing the fluctuation management and fluctuation management of the lock-up apply pressure,
A desired slip lockup state or complete lockup state can always be obtained.

In the device described in Japanese Patent Application Laid-Open No. 63-47562, which is a prior art, the extended position of the spring is the lock-up position. Therefore, if a valve stick occurs with the spring fully extended, the engine is locked even if the engine is started. The engine is up and cannot start. On the other hand, in the present application, since the extended position of the spring is the lock-up releasing position, even if the valve stick is generated in a state where the spring is fully extended, the control valve is in the lock-up releasing position, and the engine can be reliably started. Can be.

In the apparatus described in Japanese Patent Application Laid-Open No. 63-47562, which is a prior art, the base pressure of the solenoid valve is a large pressure, and the line pressure is such that the magnitude of the oil pressure changes when the engine is driven. And the accuracy of the control pressure is not good. On the other hand, in the present application, since the pressure is low and a constant pilot pressure is used, not only the size of the solenoid valve can be reduced, but also a high-precision control pressure can be generated.

In the present application, the extension position of the spring is the lock-up release position as described above, and the release pressure is applied to the spring, so that when the release pressure partially remains when the control pressure is zero, complete lock-up occurs. Although it is not possible, the pilot pressure is forcibly supplied to the spool to push the spring in the direction of contracting, thereby achieving a complete lockup with zero control pressure.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

 First, the configuration will be described.

FIG. 1 shows an operation control device of a lock-up clutch according to an embodiment, and includes a torque converter 1 (an example of a fluid transmission device).
Are fixed to a case via a pump impeller 2 (input element) driven by an engine (drive source) (not shown), a turbine runner 3 (output element) driven via hydraulic oil, and a one-way clutch 4. And a lock-up clutch 6 that can directly connect the pump impeller 2 and the turbine runner 3.

The turbine runner 3 and the lock-up clutch 6
Between them, a clutch damper 7 using a torsion spring is provided to suppress excessive torque fluctuation at the time of lock-up.

The hydraulic control device for the lock-up clutch 6 includes a torque converter connected to a torque converter apply pressure chamber 8 (fastening pressure chamber) and a torque converter release pressure chamber 9 (release pressure chamber) formed with the lock-up clutch 6 interposed therebetween. Apply pressure oil passage 10 and torque converter release pressure oil passage
11, a lock-up control valve 12 to produce these torque converter apply pressure P _{T / A} and the torque converter release pressure P _{T / R,} the torque converter pressure P _T as the base pressure of the torque converter apply pressure P _{T / A} A torque converter relief valve 13 for preventing it from becoming excessive,
Lock-up solenoid pressure P for actuating the lock-up control valve 12 a pilot pressure P _P as base pressure
_{It is} composed of a lock-up solenoid valve 14 for producing _{SOL·L / U} based on an external duty command.

The lock-up control valve 12 is a hydraulic control valve as a differential pressure control means for performing lock-up release, slip lock-up, and complete lock-up, and has a spool 12b, a plug 12c, a sleeve 12d, and a spring 12e in a valve hole 12a. Ports 12f, 12g, 12h, 12i, 12j, 12k, 12l, and 12m are formed in the valve hole 12a.

The land diameter of the spool 12b and the plug 12c
d ₀ , d ₁ , d ₂ , and d ₃ are given by a relationship of d ₀ > d ₁ > d ₂ > d ₃ , and are opposed to the torque converter release pressure _{PT / R} to apply the torque converter apply pressure _{PT / A.} Having a pressure receiving portion.

The port 12f communicates with the lock-up solenoid pressure oil passage 18, and the lock-up solenoid pressure P _{SOL·L / U} is supplied by the operation of the lock-up solenoid valve 14.

Port 12g is a drain port and port 12g
h and 12m are ports communicating with the release pressure oil passage 11, port 12i is a port communicating with the torque converter pressure oil passage 16, port 12j is a port communicating with the apply pressure oil passage 10, and port 12k is said port 12i, a port for communicating with the oil cooler 17 together 12j, the port 12l is a port constantly pilot pressure P _P is supplied.

The torque converter relief valve 13 is a valve for preventing the torque converter pressure _{PT from} becoming excessive.The valve hole 13a has a spool 13b having an oil hole and a spring 13c.
When the torque converter pressure _PT from a pressure regulator valve (not shown) is high, an upper limit pressure is defined by a drain.

The lock-up solenoid valve 14 is a solenoid
To supply the pilot pressure P _P to the port 12f is closed at the time of OFF, and drain the pilot pressure P _P open at the time of the solenoid ON, it is a valve to create a lock-up solenoid pressure P _{SOL · L / U.}

The lock-up duty solenoid 20 provided in the lock-up solenoid valve 14 is used as an actuator, and an AT control unit 21 that issues a command to the solenoid 20 and a lock-up electronic control device are configured by sensors that provide various types of input information. I have.

As the sensors, engine speed sensor 22 for detecting an engine speed N _E, the transmission output shaft rotational speed (= vehicle speed) N _O detecting the AT output shaft rotational speed sensor 23,
Throttle opening sensor 24 for detecting throttle opening TH,
_A pressure reversing switch 25 for detecting reversal of the pressure level between the torque converter apply pressure _{PT / A} and the torque converter release pressure _{PT / R} is provided.

The contact of the pressure reversing switch 25 is connected to the apply pressure oil passage 10
And a spool 26 (installed in the valve unit) on which hydraulic pressure from the release pressure oil passage 11 acts on both end surfaces.

The AT control unit 21 has a shift control program that outputs a command to a shift solenoid (not shown) according to a predetermined shift point characteristic, and a line pressure control program that outputs a command to a line pressure duty solenoid (not shown) according to a predetermined line pressure characteristic. In addition, a lock-up control program for performing lock-up control by outputting a command to the lock-up duty solenoid 20 according to a predetermined lock-up schedule as shown in FIG. 4 is incorporated.

 Next, the operation will be described.

FIG. 2 is a flow chart of a main routine showing a flow of lock-up control performed according to the lock-up schedule of FIG. 4, and FIG. 3 is a diagram showing a slip which is performed transiently when shifting from a torque converter state to a complete lock-up state. It is a flowchart of the subroutine which shows the flow of lockup control.

First, the flow of the lock-up control operation will be described with reference to the flowchart of FIG.

In step 31, the throttle opening TH and the vehicle speed V (= transmission output shaft speed N _O ) are read.

In step 32, it is determined from the lock-up schedule in FIG. 4 whether the current vehicle state is in the torque converter region.

Then, if it is in the torque converter region, the process proceeds to step 33, and if it is not in the torque converter region, the process proceeds to step.

In step 33, a duty ratio of 0%, that is, an OFF signal is output to the lock-up solenoid 20, and the released state of the lock-up clutch 6 is maintained.

In step 34, it is determined based on the throttle opening TH, the vehicle speed V, and the lockup schedule in FIG. 4 whether or not the current vehicle state is in the lockup region.

Then, if the current vehicle state is in the lock-up area, the process proceeds to step 35, and if the current vehicle state is in the slip lock-up area, the process proceeds to step 36.

In step 35, a duty ratio of 100%, that is, an ON signal is output to the lock-up solenoid 20, and the lock-up clutch 6 is kept in a completely engaged state.

In step 36, as shown in FIG. 3, slip lock-up control is performed by duty ratio variable control while monitoring the slip amount.

Next, the flow of the slip lock-up control operation when step 36 is selected will be described with reference to the flowchart of FIG. 3, and each operation characteristic will be described with reference to the time chart of FIG.

In step 41, the engine rotational speed N _E and the throttle opening
TH, transmission output shaft speed N _O and switch signal S are read.

In step 42, the slip amount ΔN is calculated by the following equation.

_{ΔN = N E -N T = N} E -N O · G However, N _T; turbine speed, G; gear ratio.

In step 43, it is determined whether or not the switch signal S from the pressure reversing switch 25 is ON.

And the switch signal S from the pressure reversing switch 25 is
If it is OFF, the initial lock-up duty is output in step 44, and in the next step 45, it is determined whether the time t from the start of the output of the initial lock-up duty is less than or equal to the set time T.

That is, the vehicle state enters the slip lockup area,
When the slip lock-up control is started, until the signal from the pressure reversing switch 25 changes from OFF to ON (however, it does not exceed the set time T), the time t _{0 in} FIG.
As shown in t ₁ from a high duty ratio a urging pressure reversal
Output the initial lock-up duty.

Then, when the torque converter apply pressure _{PT / A} exceeds the torque converter release pressure _{PT / R} with the stroke of the lock-up clutch 6 and the signal from the pressure reversing switch 25 changes from OFF to ON, the process proceeds to step 43. proceeds to step 46, in step 46, as shown in the time t ₁ ~t ₂ of FIG. 5, after the low duty ratio b to the extent that the lock-up clutch 6 is not returned, the duty ratio increasing rate with a gradient θ soft lockup command for by increasing match actual slip amount .DELTA.N set slip amount .DELTA.N ₁ is output.

Here, the soft lock-up means a state in which the lock-up clutch 6 is lightly engaged while allowing a change in the slip amount ΔN, while the slip lock-up is a lock-up state in which the slip amount ΔN is kept constant. Refer to it.

In step 47, whether smaller than the set slip amount .DELTA.N ₁ to slippage .DELTA.N is preset is determined, until .DELTA.N is less than .DELTA.N _1, the output of the soft lockup duty is continued.

Then, .DELTA.N <becomes a .DELTA.N _1, the process proceeds to step 48 after, as shown in time t ₂ subsequent Figure 5, the slip amount .DELTA.N
There feedback command to increase or decrease or retain the duty ratio so as to match the target slip amount .DELTA.N ₂ is output.

That is, when ΔN ≦ ΔN ₂ ± α, the routine proceeds to step 52, where the duty ratio is held, and when ΔN> ΔN ₂ + α, step 50
When ΔN <ΔN ₂ −α, the routine proceeds to step 51, where the duty ratio is decreased, and the slip amount Δ
Slip lock-up control for making N equal to the target slip amount ΔN ₂ is performed.

Next, an example of setting the land diameter of the lock-up control valve 12 will be described.

First, in the valve balancing type, since the land diameters d _o , d ₁ , d ₂ , and d ₃ of the spool 12b and the plug 12c have the relationship shown in FIG. 6,
It becomes the following formula.

Therefore, It is represented by Therefore, P _{SOL · L / U} = 2.0 kg / cm ² (pressure at 56% duty ratio) P _{T / R} = 3.8 kg / cm ² P _{T / A} = 3.5 kg / cm ² d ₁ = 14.34 mm, d ₂ = 11.00 mm, when giving d ₃ = 7mm F _L12 = 0.5kg calculating a d _0, the d ₀ = 15.03mm.

Note that d ₂ and d ₃ are determined by randomly substituting numerical values, and other solutions are also possible.

As described above, the lock-up clutch operation control device according to the embodiment has the following features.

The spool 12b of the lock-up control valve 12 is provided with a pressure receiving portion to which the torque converter apply pressure _{PT / A} is applied in opposition to the torque converter release pressure _{PT / R} ,
The lockup solenoid pressure P _{SOL • L / U} to be applied is given by a pressure corresponding to the differential pressure ΔP between the two pressures _{PT / A} and _{PT / R} , as shown in the above equation. Therefore, variations and fluctuations of the torque converter up apply pressure _{PT / A} are allowed and absorbed by the lock-up control valve 12 based on the differential pressure control.

The relationship between the lock-up duty and the differential pressure ΔP is given by FIG. 7, and the relationship between the lock-up duty and the lock-up solenoid pressure is given by FIG. The solenoid pressure P _{SOL·L / U} and the differential pressure ΔP can be monitored, and the output constant of the lock-up duty can be input to the AT control unit 21 in advance.

Therefore, a desired slip lock-up state or lock-up state can always be easily obtained without necessity of managing dispersion and fluctuation of the torque converter up apply pressure _{PT / A} , which causes an increase in cost.

As described above, the embodiments have been described based on the drawings. However, the specific configuration is not limited to the embodiments, and even if there is a design change or the like without departing from the gist of the present invention, it is included in the present invention. .

For example, in the embodiment, as the differential pressure control means,
An example is shown by the lock-up control valve 12 having a pressure receiving portion which is a torque converter apply pressure P _{T / A} is given against a torque converter release pressure P _{T / R,} a torque converter release pressure P _{T / R} and the torque _A means for detecting the converter apply pressure _{PT / A} and controlling the hydraulic pressure so that the torque converter release pressure _{PT / R} matches the target differential pressure while monitoring the differential pressure detection value may be used.

(Effect of the Invention) As described above, in the lock-up clutch operation control device of the present invention, the lock-up control valve as the differential pressure control means has a configuration including a valve hole, a spool, and a spring. The valve hole has a torque converter pressure port, a pilot pressure port, an apply pressure port, a release pressure port, and a control pressure port, and a spool position where a spring is fully extended is set as a lock-up release position. The base pressure of lock-up apply pressure and lock-up release pressure created by the lock-up control valve,
The pilot pressure, which is a constant pressure, is supplied to the solenoid valve as a base pressure for generating the control pressure, and the force of the pilot pressure acts on the spool of the lock-up control valve to oppose the spring force. Acts on the spool of the lock-up control valve and opposes the spring force.The force of the lock-up apply pressure acts on the spool of the lock-up control valve to assist the spring force, and reduces the lock-up release pressure and pilot pressure. In addition to the relationship between the forces acting on the spool, the control pressure from the solenoid valve assists the spring force, and by controlling this control pressure, the spool is moved to lock-up apply pressure and lock-up release. To control the pressure differential A desired slip lock-up state can be easily obtained in the slip lock-up control while allowing a variation in the lock-up apply pressure by the differential pressure control. And the effect of achieving high-precision control as well as downsizing of the solenoid valve.

[Brief description of the drawings]

1 is an overall view showing an operation control device of a lock-up clutch according to an embodiment of the present invention, FIG. 2 is a flowchart showing a main routine of the lock-up control operation, and FIG. 3 is a subroutine of a slip lock-up control operation. FIG. 4 is a flow chart, FIG. 4 is a diagram showing an example of a lock-up schedule in the apparatus of the embodiment, FIG. 5 is a time chart showing characteristics of slip lock-up in the apparatus of the embodiment, and FIG. FIG. 7 is a schematic diagram showing the relationship of the force acting on the valve, FIG. 7 is a differential pressure characteristic diagram with respect to lock-up duty, and FIG. 8 is a lock-up solenoid pressure characteristic diagram with respect to lock-up duty. DESCRIPTION OF SYMBOLS 1 ... Torque converter (fluid power transmission) 2 ... Pump impeller (input element) 3 ... Turbine runner (output element) 6 ... Lock-up clutch 8 ... Torque converter apply pressure chamber 9 ... Torque converter release pressure chamber 12 Lockup control valve (differential pressure control means) 14 Lockup solenoid valve 21 AT control unit

Claims (1)

(57) [Claims] 1. A fluid transmission device comprising: an input element driven by a drive source; an output element driven via hydraulic oil; and a lockup clutch capable of directly connecting the input / output element; and the lockup clutch. An operation control device for a lock-up clutch including a lock-up control valve as a differential pressure control means for controlling a differential pressure between a lock-up apply pressure chamber and a lock-up release pressure chamber formed across the lock-up pressure chamber. The valve is configured to have a valve hole, a spool, and a spring.The valve hole has a torque converter pressure port, a pilot pressure port, an apply pressure port, a release pressure port, and a control pressure port, and the spring has been extended. Set the spool position to the lock-up release position and set the torque converter The pilot pressure is the base pressure of the lock-up apply pressure and the lock-up release pressure created by the lock-up control valve.The pilot pressure, which is a constant pressure, is supplied to the solenoid valve as the base pressure that creates the control pressure. Force acts on the spool of the lock-up control valve and opposes the spring force. The force of the lock-up release pressure acts on the spool of the lock-up control valve and opposes the spring force, locking the force due to the lock-up apply pressure. Acts on the spool of the up control valve to assist the spring force, and opposes the lock-up release pressure and the pilot pressure. In addition to the relationship of the force acting on the spool, the control pressure from the solenoid valve increases the spring force. To help control this pressure. An operation control device for a lock-up clutch, wherein a differential pressure between a lock-up apply pressure and a lock-up release pressure is controlled by moving a spool by controlling.