JPH0730839B2 - Lockup torque converter slip control device - Google Patents

Description

The present invention relates to a device for controlling slip (relative rotation between torque converter input / output elements) of a lockup torque converter used in an automatic transmission.

(Prior Art) In an automatic transmission, it is unavoidable that the power transmission efficiency deteriorates due to the slip of the torque converter inserted in the power transmission system. Therefore, it has been proposed to use a lockup torque converter instead. In this lockup torque converter, an operating mode in which the output element (usually a turbine runner) is rotated while increasing the torque under the reaction force of the stator caused by the stirring hydraulic oil from the input element (usually a pump impeller) driven by the engine ( (Converter state) and an operation mode in which the input / output elements are directly connected to each other by coupling the lockup clutch and the rotation toward the input element is taken out as it is (lockup state), and engine torque fluctuation becomes a problem. In addition, the former operation mode is used in the relatively low engine speed range where torque increase is required, and the latter operation mode is used in the other high engine speed range. Therefore, the lockup torque converter can improve the fuel efficiency of the engine by eliminating slip between input / output elements in the high engine speed range (high vehicle speed range), as compared with the normal torque converter having only the former operation mode. Yes, it is being used in many automobiles today.

By the way, the conventional lockup torque converter has the above 2
Since only one of the operation modes is selectively used, the lockup vehicle speed, which is the criterion for that, must be set to a sufficiently high vehicle speed that the torque fluctuation of the engine becomes small enough not to vibrate the vehicle body, and the lockup period is short. As a result, the reality is that it is not possible to achieve a sufficient fuel efficiency improvement effect.

Therefore, although the torque fluctuation of the engine becomes a little problem, the torque fluctuation of the torque converter is absorbed while the torque fluctuation of the engine is absorbed so that the torque fluctuation of the engine is not a problem in the low rotation speed range where the torque is sufficiently low. A slip control technique for a lock-up torque converter that suppresses slips and eliminates the above-mentioned problems has been already proposed in Japanese Patent Application Laid-Open No. 59-86750.

This technique releases the lockup clutch by making the lockup control chamber pressure on one side of the lockup clutch the same as the converter chamber pressure on the other side when the slip control valve is in the converter position, and when the slip control valve is in the slip position, The lockup control chamber pressure is reduced to a value that depends on the opening of the variable orifice that changes according to the difference between the torque converter output element and the transmission torque of the lockup clutch, and the lockup clutch is slip-engaged. At this time, all the lockup control chamber pressures are eliminated so that the lockup clutches are completely connected.

(Problems to be solved by the invention) However, in this type of slip control device, due to the oil passage structure of the automatic transmission including the working oil passage and the slip control oil passage of the torque converter, the slip control oil passage A high-pressure oil passage exists in the vicinity through a seal (for example, a seal member interposed between the converter chamber and the lock-up control chamber). From this high-pressure oil passage into the slip control oil passage, the working oil is passed through the seal. Is inevitable to leak.

The amount of hydraulic oil leakage increases as the temperature rises and the viscosity decreases, and the amount of hydraulic oil leakage increases as the amount of leakage increases (the hydraulic oil temperature increases) in the lockup control chamber. Generate residual pressure.

This residual pressure changes as shown in a, b, and c in Fig. 7 when the slip control possible limit line that allows normal slip control is shown for hydraulic oil temperatures of 40 ° C, 80 ° C, and 100 ° C, respectively. Let
The area on the right side of the lines a, b, and c should be the slip control area for each temperature. In other words, the slip controllable range becomes narrower as the operating oil temperature rises and as the throttle opening (engine load) increases and the vehicle speed further rises.

In the conventional slip control device, however, the slip control start line for switching the slip control valve from the converter position to the slip position is set as shown by d in FIG. 7, and if the vehicle speed is V ₁ or higher, it is related to the hydraulic oil temperature and the engine load. Since the slip control is started without the slip control, there is a problem that the slip control is executed more frequently even though the slip control is in an unqualified region as the temperature of the hydraulic oil rises.

When inaccurate slip control occurs in the direction of excessive slip amount, unnecessary friction of the lock-up clutch causes early wear of the clutch facing, and a large amount of frictional heat causes the hydraulic oil temperature to rise more and more. With a vicious circle.

The present invention does not hope to improve fuel efficiency even if slip control is performed in the unqualified range, and based on the fact that it is better not to perform slip control in this region in view of the above problems, such a region setting is made. An object of the present invention is to solve the above-mentioned problem by switching the slip control valve to the slip position according to the temperature of the Tokuru converter hydraulic oil, the engine load, and the vehicle speed so as to be possible.

(Means for Solving the Problems) For this purpose, the slip control device of the present invention can control the relative rotation between the input and output elements of the torque converter by engaging the lockup clutch, and when the slip control valve is in the converter position. The lockup control chamber pressure on one side of the lockup clutch is made equal to the converter chamber pressure on the other side, and the lockup clutch is released.
In a lock-up torque converter in which the lock-up clutch is engaged when the slip control valve is in the slip position due to a decrease in the lock-up control chamber pressure, the torque converter working oil temperature rises, the engine load increases, and the vehicle speed further increases. As the slip control range changes, the slip control start line for switching the slip control valve to the slip position is changed so as to reduce the slip control range.

(Operation) When the slip control valve is in the converter position, the lock-up control chamber pressure is made the same as the converter chamber pressure to release the lock-up clutch, and the slip control is executed without limiting the relative rotation between the input / output elements of the Tokule converter do not do. When the slip control valve is in the slip position, the lockup clutch is engaged by an appropriate decrease in the lockup control chamber pressure, and the slip control is executed.

By the way, the slip control start line for switching the slip control valve from the converter position to the slip position is controlled by the slip control range changing means,
Also, as the engine load increases and the vehicle speed further increases, the slip control range is changed so that the slip control possible limit line changes due to these changes.
The start of the slip control can be changed following this. Therefore, it is possible to avoid the problem that the slip control is performed in the area where the slip control cannot be normally executed, and the clutch facing is prematurely worn due to unnecessary drag of the lock-up clutch, or the frictional heat caused by it is activated. If the oil temperature rises more and more, a vicious circle will not occur.

(Example) Hereinafter, the present invention will be described in detail based on an illustrated example.

FIG. 1 shows an embodiment of the slip control device of the present invention.
Indicates a lockup torque converter to be slip-controlled by this device, which is mainly composed of a pump impeller (torque converter input element) 2, a turbine liner (torque converter output element) 3, and a stator 4.
The pump impeller 2 has a converter cover 5 welded to it.
It is assumed that the engine crankshaft (not shown) is drivingly connected to the engine crankshaft via the shaft and is constantly driven by the engine during operation. A hollow pump drive shaft 6 is further welded to the pump impeller 2, and the pump 7 is constantly driven by this shaft during operation of the engine.

The turbine runner 3 is provided with a turbine hub 9 which is rivetably fastened to the inner periphery of the turbine runner 3, through which the turbine runner 3 is slidably fitted on a sleeve 10, and the sleeve 10 is connected to the torque converter output shaft 11 To form a part of the output shaft 11 by spline coupling so as not to move in the axial direction. The turbine hub 9 and the sleeve 10 are integrally formed with flanges 9a and 10a that face each other and extend outward in the radial direction. The flanges 9a and 10a are slidably fitted to each other to form a pressure chamber between them. Define twelve. Ball grooves 13 and 14 are formed on the facing surfaces of the flanges 9a and 10a, respectively, and these ball grooves 13 and 14 extend along an arc having a radius R centered on the torque converter output shaft 11 and face each other. . In addition, ball grooves 13,14
Although the bottom surfaces 13a and 14a of each are parallel to each other, they are inclined by an angle of θ with respect to the rotating surfaces of the flanges 9a and 10a as shown in FIG. 2, and are interposed between these ball groove bottom surfaces 13a and 14a. A common ball 15 is narrowed between the ball grooves 13 and 14 to form a cam mechanism.

A lockup clutch 16 is separately slidably fitted on the sleeve 10, and the lockup clutch 16 is isolated from the converter chamber 17 when the outer peripheral clutch facing 16a is pressed against the converter cover 5. A lockup control room 18 is created. Lockup control room 18
Is always communicated with the pressure chamber 12 through the holes 10b and 10c formed in the sleeve 10, and is communicated with the converter chamber 17 through the holes 10b and 10d in the sleeve 10 and the axial slit 9d formed in the turbine hub 9. It should be noted that the slit 9b and the hole 10d constitute a variable orifice 19 whose opening degree is shaded in FIG. 3 depending on the overlapping amount, and the variable orifice 19 is connected between the converter chamber 17 and the lockup control chamber 18 according to the opening degree. Adjust the degree of communication. In addition, an orifice may be formed in the hole 10c to improve steady-state stability when hydraulic pressure of the lock-up control chamber 18 is fed back to the pressure chamber 12 and to prevent hunting during step response.

The lockup clutch 16 further includes an annular member having an L-shaped cross section.
Tooth 20a and flange 10a formed by fixing 20 to the free edge
By meshing with the teeth 10e formed on the outer peripheral edge of
A lockup clutch (16) is drivingly connected to the sleeve (10) so as to be movable in the axial direction.

The stator 4 of the torque converter 1 is placed on a hollow fixed shaft 22 via a one-way clutch 21, and annular passages 23, 24 are respectively provided between the shaft 22 and the pump drive shaft 6 and the torque converter output shaft 11. Set. The annular passage 23 guides the working oil from the oil pump 7 into the torque converter 1 and removes the working oil from the annular passage 24. During this period, the torque converter is provided by a pressure-holding valve or the like provided in the working oil passage thereafter. 1, the inside of the converter chamber 17 has a constant pressure Pc.
Is kept at.

Further, the lock-up control room 18 has the torque converter output shaft 11
The communication port 25a of the slip control valve 25 is communicated through the hollow hole 11a, and the control valve is composed of a spool 25b and a spring 25c that elastically supports the spool 25b at the converter position shown in the upper half.
The governor pressure P _G, which increases as the vehicle speed increases, is supplied to the chamber 25d facing the end surface of the spool 25b far from the spring 25c, and the governor pressure causes the spool 25b to be in the slip position shown in the lower half portion as appropriate. The spool 25b allows the port 25a to communicate with the inlet port 25e at the converter position, and allows the port 25a to communicate with the drain port 25f with the fixed orifice 26 at the slip position, and supplies the converter chamber pressure Pc to the inlet port 25e.

The oil temperature generated by the slip control range changing means 27 and the engine load corresponding pressure (control pressure) P _T are supplied to the chamber 25g facing the end surface of the spool 25b acted by the spring 25c,
Therefore, the stroke control of 25b is performed by the pressure P _T and the force of the spring 25c that is directed to the right in FIG. 1 and the force P _G that is directed to the left in FIG.

The slip control area changing means 27 includes a control pressure generating circuit 28,
A line pressure Pl that increases as the throttle opening (engine load) increases from one end is supplied, and the other end is drained. Then, in the circuit 28
29 and Olifis 30 will be installed. The chiyoke 29 has a long flow path length with respect to the flow path cross-sectional area, and is greatly affected by the kinematic viscosity of the passing fluid, and as the kinematic viscosity coefficient decreases as the oil temperature rises, the passing flow rate increases under the same pressure. Let Orihuis 30 is hardly affected by kinematic viscosity (temperature),
Pass a constant flow rate (if the pressure is the same) determined by the orifice size. Therefore, when the oil temperature is 40 ° C., 80 ° C., and 100 ° C., a control pressure P _T that changes as shown in FIG. 4 is generated between the chiyoke 29 and the orifice 30, and this control pressure is the temperature. As the line pressure Pl is as shown in the figure, it increases as the throttle opening (engine load) increases, and has a value corresponding to the oil temperature and the engine load.

The operation of the above embodiment will be described below.

In the balance formula of the force applied to the spool 25b of the slip control valve 25, if the pressure receiving surfaces at both ends are A and the spring force of the spring 25c is F _S ,
It is expressed by A × P _G = A × P _T + F _S , and from this formula Is required.

By the way, F _S / A is a constant value, and as the control pressure P _T has a characteristic that it becomes a function of the throttle opening and the hydraulic oil temperature as described above, that is, it increases as the temperature increases.
The value of the governor pressure P _G for switching b from the converter position shown in the upper half part to the slip position shown in the lower half part becomes higher as the throttle opening and the hydraulic oil temperature rise. Therefore, the slip control start line at which the slip control is started by the above switching is the 7th line when the operating oil temperature is 40 ° C, 80 ° C, 100 ° C.
It becomes something like a ', b', c'in the figure.

The slip control valve 25 is in the upper half state in FIG. 1 in the region on the left side in FIG. 7 from the slip control start line for each hydraulic oil temperature. In this case, the converter chamber pressure P _C is the ports 25e, 25a, hollow holes. It is supplied to the lock-up control chamber 18 via 11a, and this chamber is made to have the same pressure as the converter chamber 17, so that the lock-up clutch 16 maintains the release position shown in FIG. 1 and operates the lock-up torque converter in the converter state. . That is, the engine-driven pump impeller 2 directs hydraulic oil to the turbine runner 3, and this hydraulic oil then returns to the pump impeller 2 via the stator 4. During this time, the hydraulic oil rotates the turbine liner 3 while increasing the torque under the reaction force of the stator 4, and this rotational power passes through the turbine hub 9, the ball 15 and the sleeve 10 and the torque converter output shaft 11
Can be taken out more.

On the other hand, the slip control valve 25 is brought into the lower half state in FIG. 1 in the right side region in FIG. 7 from the slip control start line for each hydraulic oil temperature. In this case, the pressure in the lockup control chamber 18
P _L is withdrawn through the fixed orifice 26, while it is replenished with pressure P _C from the converter chamber 17 through the variable orifice 19. Thus, during this period, the pressure P _L in the lockup control chamber 18
Is determined by the opening of the variable orifice 19, and this pressure P _L
The lockup clutch 16 slides and frictionally joins to the converter cover 5 at a degree according to the above condition, and transmits power in an intermediate state between the converter state and the lockup state. Here, considering the force acting on the turbine hub 9, since the frictional force between this and the ball 15 is slight, ignoring this, the turbine hub 9 produces the generated torque as shown in FIG. The force F _T generated by _{T T} and the force F _L generated by the pressure difference between the converter chamber pressure P _C and the lockup control chamber pressure P _L acting on the pressure receiving area S of the turbine hub 9 in the chamber 12 are added, and the ball 15 is It balances the resultant force of these forces with the drag force N. By the way, F _T and F _L are respectively F _T = T _T / R (1), F _L = (P _C −P _L ) ×
Represented by S ... (2), also F _T in the above balanced condition, F _L are each F _T = N sin θ, since represented even _{F L = N cos θ, F} L
The relational expression of tan θ = F _T (3) is obtained.

Regarding the transmission torque T _L of the lockup clutch 16, if the constant determined by the pressure receiving area and radius is K, then T _L = K
(P _C −P _L ) ... represented by the equation (4), and from this equation and the equations (1) to (3) above. And the result is that between T _L and T _T The relational expression of is established. In this equation, K, S, R, and θ are fixed values, so Is a constant, and if this is replaced with k, the above equation becomes T _L = k × T _T (5).

From equation (5) above, the transmission torque of the lockup clutch
It can be seen that T _L and the torque T _T generated by the turbine runner 3 are balanced at a constant ratio.

From this balanced state, when the turbine torque T _T increases,
In FIG. 2, the ball 15 is moved downward, and the cam action with the ball groove bottom surfaces 13a and 14a causes the turbine hub 9 to axially move to the right in this figure. This axial movement displaces the slit 9b in the direction of the dotted arrow in FIG. 3 and reduces the opening of the variable orifice 19. As a result, the converter room 17 is passed through the variable orifice 19 to the lockup control room.
The pressure in the lockup control chamber 18 decreases as described above, while the pressure removed from the lockup control chamber 18 through the fixed orifice 26 as described above is constant. Therefore, the pressure in the lockup control chamber 18 satisfies the relation of the above equation (5). To be lowered.

Conversely, when the turbine torque T _T becomes smaller from the above-mentioned balanced state, the balls 15 are moved upward in FIG. 2 and the turbine hub 9 is axially moved leftward in this drawing. This axial movement displaces the slit 9b in the direction of the solid line arrow in FIG. 3 and increases the opening degree of the variable orifice 19. As a result, the pressure from the converter chamber 17 to the lockup control chamber 18 via the variable orifice 19 increases, and the pressure in the chamber 18 is increased so that the relationship of the above equation (5) is established. In performing the above control, the balls 15 forming the cam mechanism move in the axial direction of the converter, so that the adverse effect of centrifugal force on the control or the like can be minimized.

By repeating this action, in the slip control area on the right side of the slip control start line for each hydraulic oil temperature in FIG. 7, the opening control of the variable orifice 19 is performed in accordance with the change of the turbine torque T _T , and the inside of the lockup control chamber 18 is controlled. The pressure P _L , that is, the slip coupling force of the lockup clutch 16 is adjusted so that the ratio between the turbine torque T _T and the transmission torque T _L of the lockup clutch 16 becomes constant as shown in the equation (5). The torque converter can be slip-controlled.

In the above embodiment, the state change of the slip control valve 25 is hydraulically controlled, but it is also possible to electronically control it as shown in FIG. In this example, the chamber 25g of the slip control valve 25 is an atmosphere open chamber, and the line pressure P _G is set in the chamber 25d instead of the governor pressure P _G.
supply l. Therefore, the circuit 31 is provided,
A line pressure Pl is supplied from one end thereof, and the pressure is eliminated from the other end thereof, and a solenoid valve 32 for opening and closing the line is provided opposite to the other end. A fixed orifice 33 and a large diameter orifice 34 having a large diameter are sequentially arranged in the circuit 31 in the line pressure supply direction, and these orifices are connected to the chamber 25d.

The solenoid valve 32 is composed of a plunger 32a, a spring 32b elastically supporting the plunger 32a in an open position shown in the figure, and a coil 32c that attracts the plunger 32a against the spring, and the coil 32c is energized (ON),
De-energization (OFF) is controlled by the controller 35. For this purpose, the controller 35 detects a signal from the oil temperature sensor 36 that detects the torque converter operating oil temperature T, a signal from the throttle opening sensor 37 that detects the engine throttle opening TH, and a vehicle speed V. The signals from the vehicle speed sensor 38 are input respectively. The controller 35 reads these input information at step 40 in FIG. 6 and sets the solenoid valve 32 as follows.
ON / OFF control. That is, in the next step 41, the oil temperature T
When the oil temperature T is 40 ° C., the table data corresponding to the line a ′ in FIG. 7 is read, and when the oil temperature T is 80 ° C., the table data corresponding to the line b ′ in the figure is read. If the oil temperature T is 100 ° C, the table data corresponding to the line C'in the figure is used. Next step 42
Then, based on the throttle opening TH and the vehicle speed V, it is determined from the table data read as described above whether or not it is in the slip control range, and if it is the slip control range, the solenoid valve 32 is turned on at step 43.
If it is not in the slip control area (converter area), the solenoid valve 32 is turned off in step 44.

When the solenoid valve 32 is on, it prevents the drain from the circuit 31 and produces a line pressure Pl in this circuit. This line pressure reaches the chamber 25d and puts the slip control valve 25 in the lower half state in the figure to enable the slip control. When the solenoid valve 32 is turned off, the circuit 31 is drained and the downstream side of the orifice 33 becomes non-pressurized, so that the chamber 25d is also set non-pressurized. At this time, the slip control valve 25 is brought into the upper half state in the figure by the spring 25c, and the torque converter can be operated in the converter state. Thus, also in this example, the same operation as the above-described example can be obtained.

(Effects of the Invention) Thus, in the slip control device of the present invention, the slip control start line is changed as described above so that the slip control range decreases as the temperature of the hydraulic oil of the torque converter increases and as the engine load increases, and further as the vehicle speed increases. Therefore, when the slip controllable limit line changes in accordance with these, the 雛 can also change the start of the slip control following this. Therefore, it is possible to avoid the problem that the slip control is performed in the area where the slip control is not normally executed, and the clutch facing is prematurely worn due to unnecessary drag of the lock-up clutch, and the frictional heat caused by it causes the hydraulic oil temperature to increase. As the price increases, the vicious circle will not occur.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a lock-up torque converter equipped with a slip control device of the present invention, FIG. 2 is a developed sectional view taken along the line II-II in FIG. 1, and FIG. Fig. 4, Fig. 4 is a control pressure characteristic diagram of the device shown in Fig. 1, Fig. 5 is a main part system diagram showing another example of the device of the present invention, and Fig. 6 is a control program executed by the controller of the device of the same example. FIG. 7 is a diagram showing the slip control area of the device of the present invention in comparison with that of the conventional device. 1 ... Torque converter 2 ... Pump impeller (torque converter input element) 3 ... Turbine runner (torque converter output element) 4 ... Stator, 5 ... Converter cover 9 ... Turbine hub, 9a ... Hub flange 9b ... … Axial slit, 10 …… Sleeve 10a …… Sleeve flange 10b, 10c, 10d …… Hole, 10e …… Tooth 11 …… Torque converter output shaft 12 …… Pressure chamber, 13,14 …… Ball groove 13a, 14a …… Ball groove bottom 15 …… Ball, 17 …… Converter chamber 18 …… Lockup control chamber 19 …… Variable orifice, 21 …… One-way clutch 22 …… Hollow fixed shaft, 25 …… Slip control valve 26 …… Fixed Orifice 27 …… Slip control area changing means 28 …… Control pressure generating circuit, 29 …… Chieoke 30 …… Fixed orifice 31 to 38 …… Slip control area changing means (31 …… Line pressure introducing circuit, 32 …… Solenoid valve) , 33,3 4 …… Fixed orifice, 35
...... Controller, 36 …… Oil temperature sensor, 37 …… Slottle opening sensor, 38 …… Vehicle speed sensor) 20 …… Annular member, 20a …… Tooth

Claims (1)

[Claims] 1. A relative rotation between torque converter input / output elements can be controlled by engaging a lockup clutch, and when a slip control valve is in a converter position, lockup control chamber pressure on one side of the lockup clutch is on the other side. When the lockup clutch is released to the same pressure as the converter chamber pressure and the lockup clutch is closed when the slip control valve is in the slip position, the lockup clutch is engaged due to the decrease in lockup control chamber pressure. Slip control range changing means is provided for changing the slip control start line for switching the slip control valve to the slip position as the oil temperature increases, the engine load increases, and the vehicle speed increase so that the slip control range becomes smaller. Lock-up torque characterized by Slip control device for converter.