JPS62127566A - Slip control device for lockup torque converter - Google Patents

Abstract

PURPOSE:To reduce the shock due to a speed change during a slip control by increasing the pressure in a lockup control chamber when a speed change is carried out during a slip control. CONSTITUTION:When the speed change of an automatic speed change gear is carried out during a slip control, a lockup control chamber pressure PL once falls. This pressure fall is detected by a pressure switch 36, and further a solenoid valve 31 is actuated by the action of the pressure switch 36. A line pressure Pl is released by the actuation of the solenoid valve 31 to reduce the pressure acting on one end of the spool 25e of a region judging valve 25, and further the port 25a communicating with a passage, which supplies a lockup control chamber pressure, is communicated with a converter chamber 17 via a port 25e. Thus, the pressure in a lockup control chamber 18 increases to increase the slip degree of a lockup clutch 16, and the occurrence of shock due to a speed change can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides a slip control system for controlling the relative rotation (slip) between the input and output elements of a lock-up torque converter inserted in the power transmission system of an automatic transmission. This relates to a control device.

(Prior art) A slip control device for a lock-up torque converter is
This is intended to reduce unnecessary slip in the torque converter and increase its power transmission efficiency, and the applicant of the present application has previously proposed a method as disclosed in Japanese Patent Laid-Open No. 59-86750.

This slip control device maintains a predetermined ratio of torque sharing between the output element of the torque converter and a lock-up clutch that bypasses the output element and transmits power.

(Problems to be Solved by the Invention) However, when this type of slip control device is used in an automatic transmission, it causes a large shift shock for the following reasons.

Figure 9 shows the shift pattern of a 3-speed forward automatic transmission (the solid line is 1
→2,2→3 upshift shift line, dotted line is 3→2,2-
)1 downshift shift line), and if the low vehicle speed range near starting or stopping, e.g. 30 km/h or less, is set as the converter area where no slip control is applied, and the rest is set as the slip control area, then the shift line is within the slip control area. Therefore, the gear shift will be performed during slip control.

To explain the case where a shift is performed during slip control, for example, a 2→3 shift shown by α in FIG. 9, as shown in FIG. 10, in the second gear, the torque converter slip The vehicle speed (difference from the converter output shaft rotation speed) is controlled to about 5 ORPM, and the vehicle speed (transmission output shaft rotation speed) is increasing in the power-on state during acceleration. At instant t1 when this acceleration has progressed to a certain extent, 2→
When the 3rd gear shift starts, the transmission output shaft torque increases in the inertia phase, and the engine speed and torque converter output shaft speed also decrease, and finally the 3rd gear shift increases.
Corresponding to the gear ratio of 1.0, the torque converter output shaft rotation speed matches the transmission output shaft rotation speed.

The partial slip control pretends to be executed to maintain the torque distribution to the torque converter output element and the lock-up clutch at a predetermined ratio, and this control
This and the converter chamber pressure P by adjusting the degree of decrease in L. This is done by adjusting the engagement force of the lock-up clutch based on the differential pressure between the lock-up clutch and the lock-up clutch.

Therefore, when the transmission output shaft torque increases in the inertia phase, the slip control operates to reduce the lockup control chamber pressure Pt by that amount as PL' and increase the engagement force of the lockup clutch. This causes an insufficient slip amount of the torque converter during the shift,
The amount of slip is extremely reduced near the end of the shift, making it impossible for the torque converter to absorb the shift shock component caused by changes in engine speed, resulting in a large shift shock.

In order to solve this problem, it may be possible to set the slip control area only to the highest gear so that there is no shift line in the slip control area, but in this case, it is possible to reduce the fuel consumption at the gears. This is unavoidable, and the effect of slip control itself is impaired, making it impractical.

(Problems to be Solved by the Invention) Since the above-mentioned problem occurs when the lock-up control chamber pressure falls below a predetermined value, the present invention solves the problem by increasing the lock-up control chamber pressure. The torque converter output element is fluidly driven by the torque converter input element, and the tightening force is increased due to the decrease in lock-up control chamber pressure, allowing a portion of the power from the torque converter input element to bypass the torque converter output element. The lock-up torque converter has a slip control region that maintains the torque distribution to the torque converter output element and the lock-up clutch at a predetermined ratio by adjusting the pressure in the lock-up control chamber. In an automatic transmission included in the system, a pressure detection means detects when the lock-up control chamber pressure becomes a predetermined value or less, and a pressure detecting means detects when the lock-up control chamber pressure becomes a predetermined value or less in a slip control region in response to a signal from the means. The lock-up control chamber is characterized in that it is provided with pressure increasing means for increasing the pressure in the control chamber when the lock-up control chamber pressure is reached.

(Function) When the torque distribution to the torque converter output element and the lock-up clutch deviates from a predetermined ratio, the lock-up control chamber pressure is adjusted to correct this and change the engagement force of the lock-up clutch. As a result, it is possible to obtain slip control that maintains the torque distribution to the torque converter output element and the lockup clutch at a predetermined ratio, and by reducing unnecessary torque converter slips, the power transmission efficiency can be increased.

Then, when the automatic transmission changes gears during such slip control, the slip control device lowers the lock-up control chamber pressure in response to the increase in the transmission output shaft torque during the inertia phase and increases the engagement force of the lock-up clutch. Attempts to reduce torque converter slip. When the lock-up control chamber pressure falls below a predetermined value, the pressure increasing means receives a signal from the pressure detecting means to detect this and increases the lock-up control chamber pressure, thereby causing the lock-up control chamber pressure to decrease as described above. Stop reducing the slip of the torque converter and conversely increase the slip of the torque converter. Therefore, the vibration component accompanying the change in engine speed during the gear shift can be absorbed by the torque fluctuation absorbing function of the torque converter, and it is possible to prevent gear shift shock from occurring during slip control.

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

FIG. 1 shows a lock-up torque converter equipped with the device of the present invention. In this figure, 1 indicates a lock-up torque converter, and this torque converter 1 includes a pump impeller (torque converter input element) 2 and a turbine runner (torque converter input element). It mainly consists of an output element) 3 and a stator 4. The pump impeller 2 is drive-coupled to an engine crankshaft (not shown) via a converter cover 5 welded thereto, and is constantly driven by this during engine operation. A hollow pump drive shaft 6 is further welded to the pump impeller 2, and a pump 7 is constantly driven through this shaft during engine operation.

The turbine runner 3 is provided with a turbine hub 9 riveted to its inner circumferential edge by rivets 8, through which the turbine runner 3 is slidably fitted onto a sleeve 10, and this sleeve 10 is connected to the torque converter output shaft 11. It forms part of the output shaft 11 by spline connection so that it does not move in the axial direction. flanges 9a, 10a extending radially outwardly facing each other on the turbine hub 9 and sleeve 10, respectively;
These flanges are slidably fitted into each other to define a pressure chamber 12 therebetween. flange 9a,
Forming ball grooves 13 and 14 on the opposing surfaces of 10a, respectively,
These ball grooves 13 and 14 are connected to the torque converter output shaft 1.
They extend along an arc of radius R centered at 1, and are opposed to each other. Furthermore, although the bottom surfaces 13a and 14a of the ball grooves 13 and 14 are parallel to each other, they are inclined at an angle of θ with respect to the rotation plane of the flanges 9a and 10a, respectively, as shown in FIG. .1
A cam mechanism is constructed by sandwiching one common ball 15 between the ball grooves 13 and 14 between the ball grooves 13 and 14.

A lock-up clutch 16 is separately slidably fitted onto the sleeve 10, and a lock-up clutch 16 isolated from the converter chamber 17 is connected to the outer clutch facing 16a of the lock-up clutch 16 while the lock-up clutch 16 is in pressure contact with the converter cover 5. A control room 18 is created. The lockup control chamber 18 includes a hole 10b formed in the sleeve 10;
It is constantly communicated with the pressure chamber 12 by the IOC, and communicated with the converter chamber 17 through the holes 10b, 10d of the sleeve 10 and the axial slit 9b formed in the turbine hub 9. The slit 9b and the hole 10d constitute a variable orifice 19 whose opening degree is changed as indicated by diagonal lines in FIG. Adjust the degree of continuity. In addition, in the hole 10c,
It is also possible to form an orifice in order to improve steady stability when feeding back the hydraulic pressure in the lockup control chamber 18 to the pressure 12 and to prevent hunting during step response.

An annular member 20 having an L-shaped cross section is further fixed to the lock-up clutch 16, and by meshing with teeth 10e formed on the free end edge of the annular member 20, the lock-up clutch 16 is drivingly connected to the sleeve 10 so as to be movable relative to the sleeve 10. do.

Further, the stator 4 of the torque converter 1 is placed on a hollow fixed shaft 22 via a - direction clutch 21, and this shaft 22
Annular passages 23, 24 are defined between the pump drive shaft 6 and the torque converter output shaft 11, respectively.

The annular passage 23 guides the hydraulic oil from the oil pump 7 into the torque converter 1, and the annular passage 24
During this time, the inside of the torque converter 1, that is, the inside of the converter chamber 17, is maintained at a constant pressure PC by a pressure holding valve or the like provided in the subsequent hydraulic oil passage.

Further, the lockup control chamber 18 communicates with the communication port 25a of the area determination valve 25 through the hollow hole 11a of the torque converter output shaft 11, and this determination valve is constituted by a spool 25b1 and a spring 25c that biases the spool 25b rightward in the figure. .

The area determination valve 25 functions to move the spool 25b according to the governor pressure PG corresponding to the vehicle speed supplied to the chamber 25d, and selectively connect the communication port 25a to the inlet port 25e or the drain port 25f with the fixed orifice 26. ,
The converter chamber pressure P is in the artificial boat 25e. guide.

The region determination valve 25 operates at a relatively low governor pressure P corresponding to a vehicle speed lower than that shown in the lower half of FIG. At this time, the state is in the upper half of FIG. 1, and when the governor pressure PG is relatively high corresponding to a vehicle speed of v1 or more, the state is in the lower half of FIG. In addition, when the line pressure P7 of the automatic transmission is supplied to the chamber 25g, it assumes the upper half state in FIG. 1 and has the function of a pressure increasing means for increasing the lock-up control chamber pressure PL.

Because of this, the chamber 25g is supplied with line pressure by the circuit 27.
A small-diameter fixed orifice 28 is inserted into this circuit, and a drain port 30 is provided in which a large-diameter fixed orifice 29 is inserted. A solenoid valve 31 is provided opposite to the atmosphere open end of the drain port 30, and this solenoid valve is connected to the solenoid 3.
The drain port 30 is opened by the plunger 31b when energized in 1a.
shall be blocked.

One end of the solenoid 31a is connected to the power supply +H, the other end is grounded through the collector emitter path of the transistor 32, and a diode 33 for surge absorption is connected in parallel to the solenoid 31a. The base of transistor 320 is connected to the output of inverting amplifier 34, the input of which is connected to power supply +B through resistor 35 and to ground through pressure switch 36.

The pressure switch 36 responds to the lock-up control chamber pressure PL, and turns OF when the value becomes 26 or more as shown in FIG.
ON when F L, Po (po < P,) or less
It has a hysteresis characteristic.

The operation of the lock-up torque converter equipped with the slip control device of the present invention configured as described above will now be described.

When the vehicle speed is low, for example in the converter region Δ below L (20 km/h) in FIG. 5, the corresponding governor pressure P,
can push the spool 25b against the spring 25c, and the area determination valve 25 maintains the upper half state in FIG. In this case, the converter chamber pressure PC is supplied to the lock-up control chamber 18 via the bow 25e, 25a and the hollow hole 11a,
Since this chamber 18 is made to have the same pressure as the converter chamber 17, the lock-up clutch 16 maintains the open position shown in FIG. 1, and the lock-up torque converter is operated in the converting state. That is, the pump impeller 2 driven by the engine
directs hydraulic oil to the turbine runner 3, which then returns to the pump impeller 2 via the stake 4. During this time, the hydraulic oil rotates the turbine runner 3 with increasing torque under the reaction force of the stator 4, and this rotational power can be extracted from the torque converter output shaft 11 via the turbine hub 9, the ball 15, and the sleeve 10.

Slip control area B where the vehicle speed is higher than the lower half of Figure 1
When , the corresponding governor pressure P is determined by the area determination valve 25.
is shown in the lower half of Figure 1. In this case, the pressure PL in the lock-up control chamber 18 is fixed.

While the variable orifice 19 is extracted through the orifice 26
Pressure P from the converter chamber 17 via . receive replenishment. Thus, the pressure Pt in this frontage ivy-up control chamber 18
, is determined by the opening degree of the variable orifice 19, and the lock-up clutch 16 is frictionally coupled to the converter cover 5 while slipping at a degree corresponding to this pressure Pt, and a converter state with no slip control and a lock-up state with no slip are established. Power is transmitted in an intermediate state.

Here, considering the force acting on the turbine hub 9, the frictional force between the hub 9 and the ball 15 is slight, so if this is ignored, the turbine torque 9 will have the generated torque as shown in FIG. Force F due to T.

The pressure difference between the converter chamber pressure Pc and the lockup control chamber pressure Pt acts on the pressure-receiving area S of the turbine/tube 9 in the chamber 12, and a force FL is added to the ball 15.
has a drag force N that balances the resultant force of these forces. by the way,
The above FT and PL are F and TT/R, respectively.

-----, (1), Ft, = (PC-PL) x
S---(2), and in the above equilibrium state, FT,
PL is respectively FT = N sin θ, PL = N cos
Since it is also expressed as θ, pLtan θ; Ft ---
The relational expression (3) is found.

Regarding the transmission torque TL of the lock-up clutch 16, if K is a constant determined by its pressure-receiving area and radius, then T
It is expressed by the formula L = K(PC-PL)-1-(4), and from this formula and the above formulas (1) to (3), TLX -t
The following relational expression holds true between an. In this formula, K, S, R, and θ are constants, and if you replace them with k, the above formula becomes TL = kX'
l'T---(5).

From equation (5) above, it can be seen that the transmission torque T of the lock-up clutch and the torque T generated by the turbine runner 3 are balanced at a constant ratio.

When the turbine torque TT increases from this balanced state, the ball 15 is moved downward in FIG. 2, and the turbine hub 9 is moved axially to the right in this figure due to the cam action with the ball groove bottom surfaces 13a and 14a. Ru. This axial movement displaces the slit 9b in the direction of the dotted arrow in FIG. 3, and reduces the opening degree of the variable orifice 19. As a result, the pressure flowing from the converter chamber 17 to the lock-up control chamber 18 via the variable orifice 19 decreases, while the pressure removed from the lock-up control chamber 18 via the fixed orifice 26 as described above is constant, so that the lock-up increases. The pressure within the control chamber 18 is reduced so that the relationship expressed by equation (5) is satisfied.

Conversely, when the turbine torque TT becomes smaller from the balanced state, the ball 15 is moved upward in FIG.
The turbine hub 9 is axially moved to the left in this figure. This axial movement displaces the sleeve 9b in the direction of the solid line arrow in FIG. 3, increasing the opening degree of the variable orifice 190. As a result, the pressure from the converter chamber 17 toward the lock-up control chamber 18 via the variable orifice 19 increases, and the pressure within this chamber 18 is increased so that the relationship expressed by equation (5) is satisfied. In carrying out the above control, the balls 15 constituting the cam mechanism move in the axial direction of the torque converter, thereby minimizing the adverse effects of centrifugal force on control, etc.

By repeating this action, in the slip region indicated by B in FIG. 5, the pressure PLs in the lock-up control chamber 18, that is, the slip coupling force of the lock-up clutch 16, is increased by controlling the opening degree of the variable orifice 19 according to changes in the turbine torque T7. By adjusting and subtracting, the turbine torque TT and the transmission torque TL of the lock-up clutch 16 are determined as shown in equation (5) above.
It is possible to perform slip control on the Rotta up torque converter so that the ratio of If the slip ratio e of the torque converter in the slip region B is designed so that k in the above equation (5) is 179, the slip ratio e of the torque converter changes continuously as shown in FIG. 5, for example, and e = 0. 1
(8=0.06 etc. are typical slip ratios), the slip ratio can be controlled to always be an appropriate value corresponding to the operating state of the engine.

When the automatic transmission changes gears during such slip control, the transmission output shaft torque in the inertia phase will change as shown in the figure if the above-mentioned gear change is from 2 to 3 gears as shown in FIG. 6, which corresponds to FIG. 10, for example. Rise to the street. In response to this, the slip control described above temporarily lowers the lockup control chamber pressure PL as shown in FIG. This pressure P is P in FIGS. 4 and 6. When the following conditions occur, the pressure switch 36 is ONI, and the input of the inverting amplifier 34 is set to a low level, and the inverting amplifier 3
4 to output an H level signal. This H level signal conducts the transistor 32, energizes the solenoid 31a by the power supply, and the solenoid valve 31 closes the drain port 30 by advancing the plunger 31b. At this time, the chamber 2, which was kept in an unpressurized state due to the difference in the inner diameter of the orifices 28 and 29,
5g is set to the same pressure as the line pressure Pt, and the area determination valve 25
does not change to the slip control region and becomes the state shown in the upper half of FIG. Thus, the lock-up control chamber pressure PL is no longer removed from the drain port 25f, and the input port 2
The convergence chamber pressure PC increases in response to the supply from the convergence chamber 5e, and the engagement force of the lock-up clutch 16 can be weakened.

When the lock-up control chamber pressure PL increases and reaches the value in the lower half of FIGS. 4 and 1, the pressure switch 36 turns OF.
F to set the input of the inverting amplifier 34 to H level, and convert the output of the inverting amplifier 34 to L level. As a result, the transistor 32 becomes non-conductive and the solenoid 31a is deenergized, so that the pressure in the chamber 25g is removed from the drain port 30, and the area determination valve 25 is in the lower half state in FIG. Control is resumed. This causes lock-up control chamber pressure Pt.

is lowered to the final control value as shown in Fig. 6, but during this time, the high lock-up control chamber pressure PL reduces the engagement force of the lock-up clutch 16 and the slip amount of the torque converter is indicated by β in Fig. 6. Make it as big as possible. In this way, the torque fluctuation absorbing function of the torque converter is kept large during the shift transition, and this function absorbs the vibration component shown in the lower half of Fig. 1, changing the transmission output shaft torque waveform to that shown in Fig. 6. By using something like this, it is possible to prevent the occurrence of shift shock.

The hysteresis characteristic of the pressure switch 36 shown in FIG. 4 is such that the time for increasing the lock-up control chamber pressure Pt, which should be performed as described above during gear shifting, is made longer in accordance with the gear shifting time of the automatic transmission. The above-mentioned shift shock prevention effect can be made even more reliable.

FIG. 7 shows another example of the present invention, in which the pressure detection means is replaced with a pressure switch 36 (see FIG. 1) and a pressure detection valve 3
Consists of 7. This valve includes a spool 37a, which has a spring 37b acting on its right end in the figure, and a lock-up control chamber pressure PL supplied to the chamber 37C on its left end in the figure.

The spool 37a is placed in the upper half position in the figure to allow the circuit 38 to communicate with the drain port 37.

The spool 37a is provided with a horizontal hole 37e passing through it in the radial direction at the left end in the figure, and check balls 37f are slidably fitted into both open ends of the horizontal hole 37e. 37g spring compressed between
energize them in the direction away from each other. In the valve housing 37h in which the spool 37a is inserted, a check ball 37f is located at the upper half position of the spool 37a in the figure.
A circumferential groove 37i is formed into which the check ball 37i is indented, and the escape resistance of the check ball 37f against this circumferential groove causes the pressure detection valve 37 to have a hysteresis characteristic as shown in FIG. 8, which is similar to that described above with reference to FIG. .

In the configuration of this example, while the lock-up control chamber pressure P is equal to or higher than the lower half of FIG.
7d to reduce the output pressure to chamber 25g to zero. As a result, the area determination valve 25 is in the upper half state in the figure in the converter area.
In the slip control region, the state shown in the lower half of the figure can be obtained, and the same effect as described above can be obtained.

The lock-up control chamber pressure PL is P in FIG. During the following
The spool 37a is moved to the upper half position in the figure by the spring 37b, and the line pressure P of the circuit 39 is supplied from the circuit 38 to the chamber 25g, and the output pressure to this chamber is set to the line pressure P.

Set it to the same value. As a result, the region determining valve 25 is placed in the upper half state in the figure even in the slip control region, and the same effect as described above can be obtained at this time as well. By setting hysteresis between the set values Po and P+ as shown in FIG. 8, the shift shock prevention effect can be made even more reliable in this example as well as in the above-mentioned example.

(Effects of the Invention) As described above, the slip control device of the present invention is configured to increase the lock-up control chamber pressure which is about to be lowered by the slip control during gear shifting of an automatic transmission, so it increases the slip of the torque converter during gear shifting. Its torque fluctuation absorption function allows it to absorb vibration components caused by changes in engine speed, and prevents shift shock when shifting during slip control in the same way as when shifting in the converter area. It is possible.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional side view of a lock-up torque converter equipped with the slip control device of the present invention, and Fig. 2 is a side view of the lock-up torque converter equipped with the slip control device of the present invention.
■Developed sectional view on the line, Figure 3 is a view from the ■ arrow in Figure 1, Figure 4 is the ON/OFF of the pressure switch in Figure 1.
5 is a slip control characteristic diagram of a lock-up torque converter according to the present invention, FIG. 6 is an operation time chart of the present invention, and FIG. 7 is a main part system diagram showing another example of the present invention. FIG. 8 is an output characteristic diagram of the pressure detection valve in FIG. 7, FIG. 9 is a region diagram showing the slip control region in the shift pattern of the automatic transmission, and FIG. 10 is an operation time chart of the conventional device. 1... Lock-up 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 -
... Teeth 11 ... Torque converter output shaft 12 ... Pressure chamber 13.14 ... Ball grooves 13a, 14a ... Ball groove bottom surface 15 ... Ball 16 ... Lock-up clutch 17 ... Convergence chamber 18... Lockup control chamber 19... Variable orifice 20... Annular member 20
a...Teeth 21...One-way clutch 2
2... Hollow fixed shaft 25... Area determination valve (pressure increase means) 26, 28.29... Fixed orifice 27... Line pressure supply circuit 30... Drain port 31... Solenoid valve 32 ...Transistor 34...Inverting amplifier 36...Pressure switch (pressure detection means) 37...Pressure detection valve (pressure detection means) 39...Line pressure supply circuit Fig. 2 Fig. 4 Locker, A 11 P desired pressure (PL) Fig. 5 Vehicle speed (fly/4) Fig. 6 Fig. 7 (Line pressure allowance) Fig. 8 Lock at $++ ap pressure (PL) Fig. 9 "6'v" Vehicle speed k, h,
.

Claims (1)

[Claims] 1. A torque converter output element that is fluidly driven by a torque converter input element, and a torque converter whose fastening force is increased due to a decrease in lock-up control chamber pressure and a portion of the power from the torque converter input element is transferred to the torque converter. Lock-up torque is equipped with a lock-up clutch that transmits the output element bypassing the output element, and maintains the torque distribution to the torque converter output element and the lock-up clutch at a predetermined ratio in the slip control region by adjusting the lock-up control chamber pressure. An automatic transmission having a converter in a power transmission system, comprising: pressure detection means for detecting when the pressure in the lockup control chamber becomes lower than a predetermined value; and upon receiving a signal from the means, the lockup control is performed in the slip control region. A slip control device for a lock-up torque converter, comprising pressure increasing means for increasing the pressure in the lock-up control chamber when the chamber pressure falls below a predetermined value. 2. The slip control device for a lock-up torque converter according to claim 1, wherein the pressure detection means has a hysteresis characteristic.