JPH06100266B2 - Line pressure control device for automatic transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a device for controlling a line pressure used for shift control of an automatic transmission.

(Prior Art) An automatic transmission determines a power transmission path by selectively operating various friction elements (clutch, brake, etc.) with a line pressure obtained by adjusting the oil from an oil pump with a regulator valve. , A predetermined shift speed is obtained (shifted).

By the way, the required engagement capacity of the friction element to be operated is proportional to the engine output torque, so that the line pressure needs to have a value corresponding to it so as to increase in proportion to the engine output torque as shown in FIG. Otherwise, if the line pressure is too high and the engagement capacity of the friction element operated by this is larger than the required value, a shift shock problem will occur, and conversely the line pressure will be too low and the friction element operated by this will be If the fastening capacity is smaller than the required value, sliding of the friction element causes seizure and transmission loss. Further, if the line pressure is too high, the driving load of the oil pump is unnecessarily increased, and the fuel consumption of the engine that drives the oil pump is deteriorated.

Therefore, the automatic transmission creates a pressure corresponding to the engine output torque and guides it to the regulator valve so that the recuperator valve can set the line pressure to a value proportional to the engine output torque.

Therefore, as a device for producing a pressure equivalent to the engine output torque, conventionally, the engine intake negative pressure or the engine throttle opening can generally represent the engine output torque.
It has been generally practiced to create a pressure corresponding to an engine suction negative pressure or an engine throttle opening degree and output the pressure as an engine output torque equivalent pressure.

(Problems to be Solved by the Invention) In this case, the line pressure is proportional to the engine suction negative pressure or the engine throttle opening as shown in FIG. 10 (a) or FIG. 10 (b). However, the engine suction negative pressure is not always proportional to the engine output torque as shown in FIG. 11 (a), and the engine throttle opening is not necessarily proportional to the engine output torque as shown in FIG. 11 (b). Therefore, it cannot be said that the line pressure characteristics in FIGS. 10 (a) and 10 (b) necessarily show the relationship with the engine output torque, and it is possible to make the line pressure a value that is surely proportional to the engine output torque. There wasn't.

For this reason, conventionally, the line pressure is too high to cause shift shock and the fuel efficiency of the engine is deteriorated, and the line pressure is too low to cause seizure of frictional elements or transmission loss, which is unavoidable.

(Means for Solving Problems) According to the present invention, a lock-up clutch is built in, and the lock-up clutch is engaged according to the pressure difference between the converter chamber and the lock-up control chamber on both sides of the lock-up clutch. A slip between torque converter input / output elements can be limited, through a variable orifice whose opening decreases as the generated torque of the torque converter output element increases in response to relative rotation between the lockup clutch and the torque converter output element, A slip control in which the lock-up control chamber is communicated with the converter chamber to adjust the pressure in the lock-up control chamber to maintain the transfer torque of the lock-up clutch and the torque generated by the torque converter output element at a predetermined ratio. With a torque converter, regulator valve regulates pressure In the case of an automatic transmission in which the shift control is performed by the line pressure controlled and the engine output torque input through the torque converter is shifted at the gear ratio of the selected shift stage, the pressure difference is proportional to the engine output torque. Recognizing the fact, the engine is expressed by the difference between the converter chamber pressure and the lock-up control chamber pressure by applying the pressure in the converter chamber and the pressure in the lock-up control chamber, respectively, facing each other to the pressure-receiving surface having the same pressure-receiving area. A differential pressure responsive valve that produces an engine torque pressure proportional to the output torque is provided, and the engine torque pressure from the differential pressure responsive valve acts on the regulator valve so that the line pressure rises as the engine torque pressure increases. It is configured as follows.

(Operation) In the torque converter, the pressure in the lock-up control chamber is adjusted by the variable orifice that responds to the relative rotation between the lock-up clutch and the torque converter output element, and is locked according to the pressure difference between this and the pressure in the converter chamber. By engaging the up clutch, slip control is performed so that the transmission torque of the lock up clutch and the torque generated by the torque converter output element are maintained at a predetermined ratio.

The automatic transmission, to which the engine output torque is input via the torque converter, is shift-controlled by the line pressure regulated by the regulator valve, and shifts the input torque according to the gear ratio of the selected shift stage. During this period, the differential pressure response valve responds to the pressure difference, outputs an engine torque pressure proportional to the engine output torque, and applies this to the regulator valve for use in line pressure control of the automatic transmission.

Since the pressure difference represents the engine output torque, the engine torque pressure output by the differential pressure response valve is also accurately proportional to the engine output torque, and the line pressure control of the automatic transmission can be accurately performed. Moreover, since the engine torque pressure is not set on the engine body side but is set on the automatic transmission side to be controlled based on the input torque of the automatic transmission, the line pressure control of the automatic transmission is performed. It can be done more accurately.

(Example) Hereinafter, the Example of this invention is described in detail based on drawing.

FIG. 1 shows a shift control hydraulic circuit of an automatic transmission equipped with the line pressure control device of the present invention, and FIG. 2 shows a shift gear train of the same automatic transmission.

First, the transmission gear train of FIG. 2 will be described. This is a final drive that drives an input shaft I to which the engine output torque from the engine output shaft E is input via a slip control type torque converter 1 and a differential gear of the vehicle. And an output shaft O drivingly connected to the drive device, and the following gear speed change mechanism and friction element are interposed between these input and output shafts to shift the power from the input shaft I and output from the output shaft O. To drive the vehicle.

The gear transmission mechanism and various friction elements are composed of the first planetary gear set G ₁ ,
Second planetary gear set G ₂ , high and reverse clutch H & R /
C, forward clutch F / C, band brake B, low and reverse brake L & R / B, and one-way clutch OWC. The first planetary gear set G ₁ is the sun gear S ₁
When a internal gear R _1, is composed from both gears S ₁ and R ₁ carrier PC ₁ which supports the pinion gear P ₁ that meshes simultaneously, also the planetary gear set G ₂ is a sun gear S _2, internal gear R ₂ and a carrier PC ₂ that supports a pinion gear P ₂ that meshes with both gears S ₂ and R ₂ at the same time. The carrier PC ₁ is connected to the output shaft O, the sun gear S ₁ can be connected to the input shaft I via the high and reverse clutch H & R / C, and the internal gear R ₁
Can be connected to the input shaft I via the forward clutch F / C. The internal gear R ₂ is connected to the output shaft O, and the sun gear S ₂ is connected to the sun gear S ₁ . The carrier PC ₂ is always fixed in one rotation direction by a one-way clutch OWC, and can be fixed in both rotation directions by a low and reverse brake L & R / B.
The band brake B can fix the sun gears S ₁ and S ₂ . The band brake B is actuated by the hydraulic pressure acting on the servo apply chamber S / A and the servo release chamber S / R having a larger operating area. That is, when the hydraulic pressure acts on the servo apply chamber S / A, the band brake B is engaged, and when the hydraulic pressure acts on the servo release chamber S / R, the band brake B is released regardless of the hydraulic pressure in the servo apply chamber S / A. To be done.

The power transmission mechanism is a high and reverse clutch H &
By operating the R / C, the forward clutch F / C, the band brake B, and the low-and-reverse brake L & R / B (one-way clutch OWC) in various combinations, each element of the planetary gear set G ₁ and G ₂ (S ₁ , S ₂ , R ₁ , R ₂ , PC ₁ and P
The rotation state of C ₂ ) can be changed, and thus the rotation speed of the output shaft O with respect to the rotation speed of the input shaft I can be variously changed. By operating the clutches and brakes in the combinations shown in the table below, the forward 3rd speed and the reverse 1st speed can be obtained.

The circles in the above table indicate the operating clutches and brakes. Further, (OWC) is displayed below L & R / B indicates that the one-way clutch OWC can obtain the first speed even when the low and reverse brake L & R / B is not operated. However, in the first speed in this case, the drive cannot be performed from the output shaft O side (that is, the engine braking does not work). In the lower part of the column of band brake B, the supply state of hydraulic pressure to the servo apply chamber S / A and the servo release chamber S / R is shown.

The slip control type torque converter 1 has a pump impeller (torque converter input element) 2 as shown in FIG.
And turbine runner (torque converter output element) 3
And the stator 4 mainly. It is assumed that the pump impeller 2 is drivingly connected to the engine crankshaft E (see FIG. 2) via the converter cover 5 welded to the pump impeller 2 and is constantly driven by the engine crankshaft E (see FIG. 2) during operation. A hollow pump drive shaft 6 is further welded to the pump impeller 2, and the pump O / P is constantly driven by this shaft during operation of the engine.

The turbine runner 3 has a turbine hub 9 secured to the inner peripheral edge thereof by a rivet 8, and the turbine runner 3 is slidably fitted onto a sleeve 10 through which the sleeve 10 is shown in FIG. The torque converter output shaft 11 functioning as the input shaft I is spline-coupled so as not to move in the axial direction to form a part of the output shaft 11. 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. Define twelve. Ball grooves 13 and 14 are formed on the facing surfaces of the flanges 9a and 10a, respectively,
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. Further, although the bottom surfaces 13a and 14a of the ball grooves 13 and 14 are parallel to each other, the bottom surfaces 13a and 14a of each of the flanges 9a and 10a are inclined by an angle of θ with respect to the rotation surfaces of the flanges 9a and 10a as clearly shown in FIG. The cam mechanism is constructed by interposing one common ball 15 between the ball grooves 13 and 14 with the ball 15 interposed therebetween.

Another lockup clutch 16 is slidably fitted on the sleeve 10, and when the lockup clutch 16 presses its outer peripheral clutch facing 16a against the converter cover 5, the lockup clutch 16 is isolated from the converter chamber 17 between them. A lock-up 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 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 shaded in FIG. 4 depending on the overlapping amount thereof, and the variable orifice 19 has a converter chamber 17 and a lockup control chamber according to the opening degree. Increase or decrease the degree of communication between 18 An orifice may be formed in the hole 10c to improve steady-state stability when the hydraulic pressure of the lockup control chamber 18 is fed back to the pressure chamber 12 and to prevent hunting during step response.

The lock-up 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 excess oil from the regulator valve 31 that regulates the hydraulic oil from the oil pump O / P to the line pressure Pl is guided to the annular passage 23, and this hydraulic oil is removed from the annular passage 24, but during that time, A constant pressure (converter chamber pressure) Pc is maintained in the torque converter 1, that is, in the converter chamber 17 by a pressure maintaining valve or the like provided in the passage.
Is kept at.

Further, the lockup control chamber 18 has a torque converter output shaft 11
The slip control valve 25 is made to communicate with the communication port 25a through the hollow hole 11a, and this control valve is composed of a spool 25b and a spring 25c for urging the spool 25b to the right in the figure. The slip control valve 25 functions to move the spool 25b according to the governor pressure P _G corresponding to the vehicle speed supplied to the chamber 25d, and selectively connect the communication port 25a to the inlet port 25e and the drain port 25f with the fixed orifice 26. Then, it is determined whether or not the torque converter is slip controlled, and the converter chamber pressure Pc is introduced to the inlet port 25e.

The operation of the slip control type torque converter configured as described above will be described below.

When the vehicle speed is low, for example, when the converter area A is V ₁ (15 km / h) or less in FIG. 5, the governor pressure P _G corresponding to this is the spool.
25b cannot be pushed against the spring 25c and the lock-up control valve 25
Keeps the upper half state in FIG. In this case, the converter chamber pressure Pc is supplied to the lockup control chamber 18 via the ports 25e, 25a and the hollow hole 11a, and the lockup control pressure P _L in this chamber 18 is made equal to that of the converter chamber 17, so that the lock The up clutch 16 maintains the disengaged position shown in FIG. 1 and operates the 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 the rotational power can be taken out from the torque converter output shaft 11 via the turbine hub 9, the ball 15 and the sleeve 10.

On the other hand, when the vehicle speed is high, for example, in the slip control region B of V ₁ or more in FIG. 5, the corresponding high governor pressure P _G can push the spool 25b against the spring 25c, and the slip control can be performed. The valve 25 is in the lower half state in FIG. In this case, the pressure P _L in the lockup control chamber 18 is extracted via the fixed orifice 26, while the pressure P _L is extracted via the variable orifice 19 into the converter chamber 17
Receive replenishment of pressure P _C from. Thus, during this period, the pressure P _L in the lockup control chamber 18 is determined by the opening degree of the variable orifice 19, and the lockup clutch 16 slides and frictionally joins to the converter cover 5 at a degree corresponding to the pressure P _L. The torque converter 1 is made to function in the following slip control states.

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 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
Has a drag force N and balances the resultant force. by the way,
The above F _T and F _L are respectively F _T = T _T / R ... (1), F _L = (P _C -P _L ) × S
... (2), and in the above-mentioned balanced state, F _T and F _L are F
_T = _Nsinθ, because represented even _{F L = Ncosθ, F L tan} θ
= F _T The relational expression of (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 above equations (1) to (3) 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 the above formula (5), 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. 3, the ball 15 is moved downward, and the turbine hub 9 is axially moved to the right in this figure by the cam action with the ball groove bottom surfaces 13a and 14a. This axial movement displaces the slit 9b in the direction of the dotted arrow in FIG. 4 and reduces the opening of the variable orifice 19. As a result, the lock-up control chamber from the converter chamber 17 through the variable orifice 19
Pressure decreases toward the 18, whereas since the pressure that is as eliminating the above-mentioned from the lock-up control chamber 18 through the fixed orifice 26 is constant, the pressure P _L of the lock-up control chamber 18
Is reduced so that the relationship of the above equation (5) is established.

On the contrary, when the turbine torque T _T becomes smaller from the above-mentioned balanced state, the balls 15 are moved upward in FIG. 3 and the turbine hub 9 is axially moved leftward in the drawing. This axial movement displaces the slit 9b in the direction of the solid line arrow in FIG. 4 to increase the opening 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 P _L 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 torque converter, so that the adverse effect of centrifugal force on the control or the like can be minimized.

In the slip control region shown by B in FIG. 5 by repeating such an operation, the pressure in the lockup control chamber 18 is controlled by controlling the opening degree of the variable orifice 19 according to the change of the turbine torque T _T.
P _L , that is, the slip coupling force of the lock-up clutch 16 is adjusted so that the ratio between the turbine torque T _T and the transmission torque T _L of the lock-up clutch 16 becomes constant as shown in the equation (5). Can be slip controlled. When the slip ratio e of the torque converter in the slip control region B is designed so that k in the expression (5) becomes 1/9, it continuously changes, for example, as shown in FIG. (e = 0.1, e = 0.06, etc. exemplify typical slip ratios), and the slip ratios can be controlled to be appropriate values that always correspond to the operating state of the engine.

The lock-up clutch transmission torque T _L and the engine output torque T _E in the slip control have a proportional relationship as is clear from the above. When the proportional constant is a, the relationship of T _E = a × T _L is established. . The lock-up clutch transmission torque T _L is proportional to the pressure difference P _C -P _L between the converter chamber pressure P _C and the lock-up control pressure P _L, and if the proportional constant is b, then T _L = b (P _C -P _L ) relation holds. From these two equations, T _E = a × b (P _C −P _L ), and the engine output torque T _E is proportional to the pressure difference P _C −P _L.

In view of this situation, the present invention provides a differential pressure response valve 27 that responds to the pressure difference P _C -P _L and outputs a pressure corresponding to this as the engine torque pressure P _T , thereby configuring an engine torque pressure generation device. It was done.

In the differential pressure response valve 27, a spool 28 is elastically supported by a spring 29 at an upper half position in FIG. 1, and a central large-diameter land 28a and small-diameter lands 28b, 28c at both ends are set on the spool 28. And
The small diameter lands 28b and 28c at both ends have the same diameter, and the pressure receiving area difference between these and the central large diameter land 28a is the same as the left end pressure receiving surface of the spool 28 facing the chamber 27a that houses the spring 29. To do.

The pressure receiving area difference between the spool lands 28a and 28b is made to face the chamber 27b, and the converter pressure P _C is supplied to this chamber and the lockup control pressure P _L is supplied to the chamber 27a. The spool 28 is designed to cut off the port 27c, which outputs the engine torque pressure P _T at the pressure adjusting position shown in the lower half, from both the input port 27d and the drain port 27e, so that the pressure difference between the spool lands 28a and 28c causes a difference in engine area. The torque pressure P _T is applied to supply the converter pressure P _C to the port 27d as the source pressure of this engine torque pressure.

The spool 28 of the differential pressure response valve 27 having such a configuration includes the lockup control pressure P _L in the chamber 27a, the spring 29, and the spool land.
Engine torque pressure P _T that acts on the pressure receiving area difference between 28a and 28c
Due to the converter pressure P _C in the chamber 27b, and the force toward the left in FIG. 1 due to the converter pressure P _C in the chamber 27b are the same. Therefore, the spring force of the spring 29 can be negligible and can be almost negligible to the extent that it holds the spool 28 in the upper half position in FIG.

P _L + P _T ≈P _C ∴P _T ≈P _C −P _L Therefore, the engine torque pressure P _T corresponds to the pressure difference P _C −P _L , and this pressure difference corresponds to the engine output torque as described above. Since they are proportional to each other, the engine torque pressure P _T produced by the differential pressure response valve 27 has a value that exactly corresponds to the engine output torque.

In the converter area A (see FIG. 5) where slip control is not performed, since P _L = P _C as described above, P _T ≈0 according to the above equation, but at this time the differential pressure response valve 27 has the spring 29. As a result, the engine torque pressure P _T is maintained at the same level as the converter pressure P _C because the upper half state in FIG. 1 is maintained, and the engine torque pressure P _T becomes 0 and the automatic transmission cannot be controlled. There is no.

The remaining hydraulic circuit of FIG. 1 controls the speed change gear train of FIG. 2 to change gears. This circuit includes a regulator valve 31, a manual valve 32, a 1-2 shift valve 33, a 2-3 shift valve 34, 3-2. Downshift valve 35, line pressure booster valve 36, 1st speed fixed range pressure reducing valve 37, accumulator 38, 3-2 timing valve 39, high and reverse clutch pressure reducing valve 40, governor valve 41, and torque converter 1, Slip control valve 25,
High and reverse clutch H & R / C, forward clutch F / C, servo apply chamber S / A and servo release chamber S / R that activate or deactivate band brake B, low and reverse brake L & R / B, oil pump O / For P,
It is configured by connecting as shown.

However, the detailed configuration and operation of the various valves 31 to 41 and the hydraulic circuits related to them are as described in Japanese Patent Application Laid-Open No. 57-144338, which is the application of the applicant of the present application.
Detailed description of these is omitted.

By the way, in the present embodiment, since the engine torque pressure P _T is used for control as the pressure corresponding to the engine output torque instead of the throttle pressure shown in the publication,
Make the following changes:

That is, the engine torque pressure circuit 50 extending from the port 27c of the differential pressure response valve 27 can be connected to the shift control pressure circuit 52 to the shift valves 33 and 34 and the 3-2 downshift valve 35 via the check valve 51. And on the other hand the shuttle valve 53
The line pressure control circuit 54 to the regulator valve 31 can be communicated with via. Further, a kick down pressure circuit 56 for branching from the line pressure circuit 55 to the shift valve 33 and the 3-2 down shift valve 35 is provided, and an orifice 57 is inserted in this circuit. On the downstream side of the orifice, the kick down pressure circuit 56 is made to communicate with the drain orifice 58 having a diameter larger than that of the orifice 57 on the one hand, and can be communicated with the shift control pressure circuit 52 via the check valve 59 on the other hand.

A kickdown solenoid 60 for opening and closing the drain orifice 58 is provided oppositely, and this solenoid closes the drain orifice 58 by the movement of the plunger 60b when the coil 60a is energized. The coil 60a is energized by the battery 62 when the kick-down switch 61 is closed, and the kick-down switch 61 is normally closed in the pedal depression limit region.

In such a shift hydraulic circuit, the engine torque pressure P _T of the circuit 50 is supplied to the regulator valve 31 via the shuttle valve 53 and the circuit 54. Therefore, the regulator valve 31 regulates the line pressure Pl to the circuit 55 to a value proportional to the engine torque pressure P _T in the slip control region as shown in FIG. 6, and the upper limit value of the engine torque pressure P _T (converter region) in the converter region. The maximum value corresponding to the same value as the pressure P _C ) is maintained.
However since the engine torque pressure as described above in slip control P _T corresponds to an engine output torque T _E, the line pressure Pl with respect to the engine output torque T _E is proportional as shown by the solid line in FIG. 7 in the slip control Change with. Note that the reason why the line pressure Pl in this figure does not fall below 2 kg / cm ² is that this value is the lower pressure regulation lower limit value of the regulator valve 31. Then, in the converter region, the line pressure Pl is kept at the maximum value regardless of the engine output torque T _{E as} shown by the dotted line in FIG. 7, and the line pressure control similar to the cutback control that raises the line pressure Pl more than usual at the time of starting is performed. can get.

In the part throttle range where the accelerator pedal is not depressed near the limit, the kick down switch 61 is open,
Drain port 58 when kick down solenoid 60 is turned off
Is open. In this case, the kick down pressure circuit 56 is in a non-pressure state, the kick down pressure is not supplied from the circuit to the corresponding valves 33 and 35, and the engine torque pressure P _T of the circuit 50 opens the check valve 51 to the circuit 52. Is reached and is supplied as shift control pressure to the corresponding valves 33 to 35 while keeping the check valve 59 closed. Therefore, the target shift control (solid line is defined by vehicle speed and engine output torque as shown in FIG. (Upshift gearshift, dotted line downshift gearshift)
Can be executed. Then, the gear shift occurs in the slip control region as shown in FIG. 8, and in this region, the line pressure Pl corresponds to the engine output torque as shown in FIG. And friction elements do not slip.

In the kick down range where the accelerator pedal is depressed to the limit, the kick down switch 61 is closed and the kick down solenoid 60 is turned on to close the drain orifice 58. In this case, a kick-down pressure of the same value as the line pressure Pl is generated in the circuit 56, and this is supplied from the circuit 56 to the corresponding valves 33 and 35, and the check valve 59 is opened to reach the circuit 52 and then the check valve. While keeping the closed state of 51, it is supplied from the circuit 52 to the corresponding valves 33 to 35, and kickdown can be obtained as desired.

(Effect of the Invention) Thus, the device of the present invention, as described above,
Since the pressure difference P _C −P _L between P _L and the converter pressure P _C corresponds to the engine output torque, the pressure corresponding to this pressure difference is created by the differential pressure response valve 27, and this pressure is Since the engine torque pressure P _T is configured to contribute to the line pressure control of the automatic transmission, it is possible to control the line pressure of the automatic transmission so that it accurately corresponds to the engine output torque. You can eliminate the problem of sticking. Further, since the engine torque pressure P _T is not determined by the information from the engine body but by the input torque of the automatic transmission that is the control target, the line pressure can be controlled to a value that further matches the request.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of an automatic transmission provided with a line pressure control device of the present invention, FIG. 2 is a skeleton diagram showing a transmission gear train of the automatic transmission, and FIG. 3 is a line III-III of FIG. FIG. 4 is a developed sectional view of FIG. 4, FIG. 4 is a view taken in the direction of arrow IV in FIG. 1, FIG. 5 is a slip control characteristic diagram of the torque verter in FIG. 1, FIG. Fig. 8 is a characteristic diagram of change of line pressure with respect to engine output torque, Fig. 8 is a shift control pattern diagram by the hydraulic circuit of Fig. 1, Fig. 9 is a required characteristic diagram of line pressure, and Figs. 10 (a) and 10 (b). FIG. 11 is a conventional line pressure change characteristic diagram, and FIGS. 11 (a) and 11 (b) are diagrams showing the relationship between engine output torque, engine suction negative pressure, and engine throttle opening, respectively. 1 …… Slip control type 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 …… Bottom of ball groove 15 …… Ball, 17 …… Converter chamber 18 …… Lock-up control chamber 19 …… Variable orifice, 20 …… Annular member 20a …… Tooth, 21 …… One-way clutch 22 …… Hollow fixed shaft, 25 …… Slip control valve 26 …… Fixed orifice, 27 …… Differential pressure response valve 31 …… Regulator valve 32 …… Manual valve, 33 …… 1-2 shift valve 34 …… 2-3 Shift valve 35 ... 3-2 Downshift valve 36 …… Line pressure booster valve 37 …… First speed fixed range pressure reducing valve 38 …… Accumulator 39 …… 3-2 Timing valve 40 …… High and reverse clutch pressure reducing valve 41 …… Governor valve 50 …… Engine torque pressure circuit 51,59 …… Check valve 52 …… Shift control pressure circuit, 53 …… Shuttle valve 54 …… Line pressure control circuit, 55 …… Line pressure circuit 56 …… Kickdown pressure circuit 60 …… Kickdown Solenoid 61 …… Kick down switch I …… Transmission input shaft G ₁ , G ₂ …… Planet gear set, O …… Transmission output shaft F / C …… Forward clutch B …… Band brake H & R / C …… High And reverse clutch L & R / B …… Low and reverse brake

Claims (1)

[Claims] 1. A lock-up clutch is built in, and the lock-up clutch is engaged according to the pressure difference between the converter chamber and the lock-up control chamber on both sides of the lock-up clutch to prevent slip between torque converter input / output elements. The lock-up control chamber communicates with the converter chamber via a variable orifice that can be limited and whose opening decreases as the torque generated by the torque converter output element increases in response to relative rotation between the lock-up clutch and the torque converter output element. The regulator valve is equipped with a slip control type torque converter that adjusts the pressure in the lockup control chamber to maintain the transmission torque of the lockup clutch and the torque generated by the torque converter output element at a predetermined ratio. Shift control with regulated line pressure In the automatic transmission in which the engine output torque input through the torque converter is shifted at the gear ratio of the selected shift stage, the pressure in the converter chamber and the pressure in the lockup control chamber are the same in the pressure receiving area. A differential pressure response valve that is applied face-to-face with the pressure receiving surface and creates an engine torque pressure proportional to the engine output torque represented by the difference between the converter chamber pressure and the lockup control chamber pressure is provided. A line pressure control device for an automatic transmission, characterized in that the engine torque pressure is made to act on the regulator valve so that the line pressure is increased as the engine torque pressure increases.