JPS6211228B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a torque converter having an input member including a pump impeller and an output member including a turbine impeller, and a multi-stage gear train, through which torque of the output member is transmitted. An automatic transmission for a vehicle includes an auxiliary transmission that transmits the power to the drive wheels, and a direct coupling clutch with slipping characteristics that is provided between the input and output members and can mechanically connect these two members,
When a predetermined high-speed gear train of the auxiliary transmission is established, the direct coupling clutch is operated to mechanically connect the input and output members to minimize slip loss of the torque converter in order to emphasize transmission efficiency. The present invention relates to a direct-coupled control device for a torque converter, which is designed to suppress the torque converter to a minimum.

The torque converter eliminates fluid slippage when the direct coupling clutch is activated, which greatly contributes to the fuel economy and quietness of the vehicle when cruising. However, if the direct coupling clutch is operated from a very low vehicle speed, There are problems like this.

The first problem is that when you are cruising at low speed and want to overtake by depressing the accelerator pedal, or even if you are approaching a climb and want to increase the output by depressing the accelerator pedal, the torque converter is not directly connected. ,
The problem is that sufficient acceleration performance cannot be obtained because the inherent torque amplification function produced by the fluid transmission of the torque converter is suppressed. Therefore, there is a contradiction in that the accelerator pedal is pressed too often, the auxiliary transmission repeatedly kicks down, which becomes more troublesome, and the fuel consumption does not decrease as expected.

However, this kind of problem can be solved by detecting the engine throttle opening and releasing the direct coupling clutch when the opening is above the specified opening, but this increases the complexity of the device and increases the frequency of release. They have to accept the disadvantage that the reduction in fuel consumption is proportionally lost.

The second problem is that activating the direct coupling clutch from low speeds means that the torque converter's direct coupling will start at low engine speeds, such as 1500 R.PM. In this low rotation range, engine torque fluctuations are large and the intervals between explosions are relatively long, resulting in increased vibration of the vehicle body.

When these vibrations match the resonant frequency of the support system of the entire power plant, including the engine, they are transmitted to the passenger compartment, creating a squealing noise, which is contrary to the intended purpose of improving quietness.

A third problem is that when the accelerator is operated, the engine torque fluctuates greatly and the entire power plant oscillates due to the counter-torque, which impairs the driving sensation. To solve this problem, detect the moving speed of the accelerator pedal,
The direct coupling clutch may be disengaged at a travel speed above a specified value, but this solution generally requires sophisticated electronics and is expensive.

The present invention was made in view of the above-mentioned problems, and when establishing a predetermined high-speed gear train of the auxiliary transmission, the coupling force of the direct coupling clutch is weak in the low speed range and strong in the high speed range, with the specified vehicle speed as the boundary. When accelerating in a low speed range, the direct coupling clutch is appropriately slipped to generate power that simultaneously achieves mechanical drive by the clutch and hydrodynamic drive by the torque converter. By performing split operation, the slip loss of the torque converter is halved, and the torque converter's inherent torque amplification function can also be used, enabling powerful and economical acceleration operation. This simple and effective control absorbs vibration and shock through the appropriate slippage of the direct coupling clutch, enabling comfortable low-speed operation, while suppressing slippage of the direct coupling clutch in high-speed ranges, enabling quiet and economical operation. The purpose is to provide equipment.

In order to achieve the above-mentioned object, the present invention configures the direct coupling clutch to be hydraulically actuated, and provides an oil passage that connects the hydraulic cylinder of the direct coupling clutch and a hydraulic oil passage that becomes high pressure when the high-speed gear train is established. In a low speed range beyond a specified vehicle speed, the coupling force of the direct coupling clutch is weakened so that the direct coupling clutch and the torque converter cooperate to transmit torque during acceleration driving, and in a high speed range, the torque converter substantially operates independently. The present invention is characterized in that a control valve device is installed to control the hydraulic pressure supplied from the hydraulic oil passage to the hydraulic cylinder in two stages, high and low, so as to strengthen the coupling force of the direct coupling clutch so as to transmit torque.

Embodiments of the present invention will be described below with reference to the drawings.

First, FIG. 1 is a schematic diagram of an automatic transmission for an automobile with three forward speeds and one reverse speed to which the present invention is applied. In the figure, the output of the engine E is transmitted from its crankshaft 1 to the drive wheels W, W' through the torque converter T, the auxiliary transmission M, and the differential gear Df in sequence.
Drive these.

The torque converter T includes a pump impeller 2 connected to a crankshaft 1, a turbine impeller 3 connected to an input shaft 5 of an auxiliary transmission M, and a stator shaft 4a supported on the input shaft 5 so as to be relatively rotatable. It is composed of a stator wheel 4 connected via a one-way clutch 7. The torque transmitted from the crankshaft 1 to the pump impeller 2 is hydrodynamically transmitted to the turbine impeller 3, and during this time, when the torque is amplified,
As is known, the stator wheel 4 bears the reaction force.

A pump drive gear 8 for driving the hydraulic pump P shown in FIG. 2 is provided at the right end of the pump impeller 2, and a stator arm 4b for controlling the regulator valve Vr shown in FIG. 2 is fixed at the right end of the stator shaft 4a. will be established.

A roller-type direct coupling clutch Cd is provided between the pump wheel 2 and the turbine wheel 3 to mechanically connect them. This is shown in Figure 2 and 2A.
To explain in detail with reference to the drawings, an annular drive member 10 having a drive conical surface 9 on the inner circumference is fixed to the inner peripheral wall 2a of the pump impeller 2. Also, turbine blade wheel 3
The inner peripheral wall 3a of the driven member 1 has a driven conical surface 11 facing parallel to the driving conical surface 9 on its outer periphery.
2 are spline-fitted to be slidable in the axial direction. A piston 13 is integrally formed at one end of the driven member 12, and this piston 13 is slidably connected to a hydraulic cylinder 14 provided on the inner circumferential wall 3a of the turbine wheel 3. Internal pressure is applied to both left and right end surfaces simultaneously.

A cylindrical clutch roller 15 is interposed between the driving and driven conical surfaces 9 and 11, and as shown in FIG. so that it is inclined at a constant angle Θ with respect to the generatrix g of the virtual conical surface Ic passing through the center,
It is held by an annular retainer 16.

Therefore, when a hydraulic pressure higher than the internal pressure of the torque converter T is introduced into the hydraulic cylinder 14 at a stage when the torque amplifying function of the torque converter T is no longer necessary, the piston 13, that is, the driven member 12, moves toward the drive member 10. being pushed. As a result, the clutch roller 15 is pressed against both conical surfaces 9 and 11.
At this time, when the driving member 10 is rotated in the X direction in FIG. 2A with respect to the driven member 12 by the output torque of the engine E, the clutch roller 15 rotates, but the center axis of the clutch roller 15 Since o is inclined as described above, its rotation gives relative axial displacement to both members 10 and 12, which causes them to approach each other. As a result, the clutch roller 15 bites between the two conical surfaces 9 and 11 and mechanically connects the drive and driven members 10 and 12, that is, the pump wheel 2 and the turbine wheel 3. Even during such operation of the direct coupling clutch Cd, if the output torque of the engine E exceeds the coupling force and is applied between the blade wheels 2 and 3, the clutch roller 15 will slip against each conical surface 9 and 11. The above torque is divided into two parts, and a part is transmitted mechanically to the input shaft 5 via the direct coupling clutch Cd, and the rest is transmitted hydrodynamically to the input shaft 5 via the two impellers 2 and 3. It will be in split operation mode.

In addition, in the operating state of the direct coupling clutch Cd,
If a reverse load is applied to the torque converter T as the vehicle decelerates, the rotational speed of the driven member 12 becomes greater than the rotational speed of the driving member 10, so that the driving member 10 relatively As the clutch roller 15 rotates in the opposite direction, the clutch roller 15 rotates in the opposite direction to apply a relative axial displacement to the members 10 and 12 to separate them from each other. As a result, the clutch roller 15 is released from being wedged between the conical surfaces 9 and 11, and enters an idling state. The transmission of the reverse load from the turbine wheel 3 to the pump wheel 2 therefore takes place only hydrodynamically.

When the hydraulic pressure of the hydraulic cylinder 14 is released, the piston 13 receives the internal pressure of the torque converter T and retreats to its original position, so that the direct coupling clutch Cd becomes inactive.

Referring again to FIG. 1, there is a low-speed gear train between the input and output shafts 5 and 6 of the auxiliary transmission M, which are parallel to each other.
G ₁ , middle speed gear train G ₂ , high speed gear train G ₃ , and reverse gear train Gr are provided in parallel. Low speed gear train
_G1 is composed of a driving gear 17 connected to the input shaft 5 via a low gear clutch _C1 , and a driven gear 18 connected to the output shaft 6 via a one-way clutch Co and meshing with the gear 17. , and the medium speed gear train _G2 meshes with a drive gear 19 connected to the input shaft 5 via a medium speed clutch _C2 , and a drive gear 19 connected to the output shaft 6 via a switching clutch Cs. The high-speed gear train _G3 includes a driven gear 20, and a drive gear 21 fixed to the input shaft 5.
It consists of a driven gear 22 connected to the output shaft 6 via a high speed clutch _C3 , and a reverse gear train.
Gr is a driving gear 23 formed integrally with the driving gear 19 of the middle speed gear train _G2 , and a driven gear 24 connected to the output shaft 6 via the switching clutch Cs.
Idle gear 2 meshing with both gears 23 and 24
It consists of 5 and more. The switching clutch Cs is provided between the driven gears 20, 24, and outputs the driven gears 20, 24 by shifting the selector sleeve 26 of the clutch Cs to a forward position on the left or a reverse position on the right in the figure. It can be selectively connected to the shaft 6.

Thus, when the selector sleeve 26 is held in the forward position as shown, the low gear clutch is
If only C ₁ is connected, the drive gear 17 will be connected to the input shaft 5.
A low speed gear train G ₁ is established, and torque is transmitted from the input shaft 5 to the output shaft 6 via this gear train G ₁ . Next, if the middle gear clutch _C2 is connected while the low gear clutch _C1 remains connected, the drive gear 19 is connected to the input shaft 5, establishing the middle gear train _G2 , and this gear Torque is transmitted from the input shaft 5 to the output shaft 6 via the column _G2 . During this time, _{the output shaft 6 rotates at a higher speed than the driven gear 18 of the low-speed gear train G 1 due} to the difference in gear ratio between the low- and middle-speed gear trains G ₁ and G 2 , so the one-way clutch Co The gear train G 1 idles and substantially stops the low speed gear train G ₁ . Furthermore, when the low speed clutch _C1 is connected, if the middle speed clutch _C2 is disconnected and the high speed clutch _C3 is connected, the driven gear 22
is connected to the output shaft 6 to establish a high-speed gear train _G3 , and torque is transmitted from the input shaft 5 to the output shaft ₆ via this gear train G3. In this case as well, the one-way clutch Co idles to bring the low-speed gear train _G1 to rest, similar to when the middle-speed gear train _G2 is established. Next, switch the selector sleeve 26 to the right reverse position,
If only the middle gear clutch _C2 is connected, the driving gear 23 is connected to the input shaft 5, and the driven gear 24 is connected to the output shaft 6, thereby establishing a reverse gear train Gr. Torque is transmitted from the output shaft 5 to the output shaft 6.

The torque transmitted to the output shaft 6 is transmitted from the output gear 27 provided at the end of the shaft 6 to the large diameter gear 28 of the differential device Df.

Figure 2 shows the low, middle, and high speed clutches in Figure 1.
2 shows a combination of an example of a hydraulic circuit for controlling the operations of C ₁ , C ₂ , and C ₃ and an example of a control valve device Dc for a direct coupling clutch Cd according to the present invention. In the figure, a hydraulic pump P sucks up oil from an oil tank R and pumps it into a hydraulic oil passage 29. After this pressure oil is regulated to a predetermined pressure by a regulator valve Vr, it is sent to a manual valve Vm. This oil pressure is the line pressure.
It's called Pl.

The regulator valve Vr has a pressure regulating spring 30 and a spring receiver 31 that supports the outer end of the spring receiver 31, and the spring receiver 31 can be moved left and right to adjust the set load of the pressure regulating spring 30. . This spring receiver 3
1, the stator arm 4b is in contact with the outer end surface of the stator wheel 4 so as to apply a reaction force acting on the stator wheel 4, that is, a stator reaction force, and the spring receiver 31 is provided with a stator arm 4b for supporting the stator reaction force. Spring 3
2 is connected. Therefore, if the stator reaction force increases, the stator spring 32 will be compressed, and accordingly the spring receiver 31 will move to the left, increasing the set load of the pressure regulating spring 30, and as a result, the hydraulic oil passage 29 will be compressed. Hydraulic pressure is increased.

A part of the pressure oil whose pressure is regulated by the regulator valve Vr is guided into the torque converter T through an inlet oil passage 34 having a throttle 33, and pressurizes the inside of the torque converter T to prevent cavitation, but this internal pressure is It is determined by the size of the throttle 33 and the strength of the spring 37 of the check valve 36 provided in the outlet oil passage 35 of the torque converter T.

The oil that has passed through the check valve 36 returns to the oil tank R via an oil cooler (not shown).

The surplus of pressure oil discharged from the hydraulic pump P is guided to the lubricating oil path 38 from the regulator valve Vr and sent to each lubricating part, but in order to ensure the minimum necessary oil pressure at this time, the pressure regulating valve 39 is It is connected to the lubricating oil path 38.

The pressure oil sent to the manual valve Vm is
is in the neutral position N shown, the clutch
It is not sent to any of C ₁ , C ₂ , C ₃ and other various hydraulic operating parts. When the valve Vm is shifted one step to the left from the illustrated position to the drive position D, the hydraulic oil passage 29 from the hydraulic pump P connects to the hydraulic cylinder ₄₀₁ of the low gear clutch _C1 . passage 41 ₁ and the spring chamber 4 of the hydraulic servo motor Sm for shifting said selector sleeve 26
2, the low gear clutch _C1 is operated (connected), and the low gear train _G1 is established as described above, and the piston 44 of the servo motor Sm is not shown in the figure. Since the selector sleeve 26 is held in the forward position shown in FIG. 1 via the shift fork 45, the reverse gear train Gr is placed in an inoperative state.

An inlet oil passage 46 connected to the input port of the governor valve Vg branches from a hydraulic oil passage 43 leading to the spring chamber 42 of the servo motor Sm, and a first signal oil passage ₄₇₁ extends from the output port of the valve Vg. do.

The governor valve Vg is a known one, and is rotated around its own rotation axis 49 by a gear 48 meshing with the large-diameter gear 28 of the differential device Df. Therefore, since its rotational speed is proportional to the vehicle speed, the governor valve Vg has a hydraulic pressure proportional to the vehicle speed, that is, the governor pressure, due to the centrifugal force acting on the weight 51 of the spool valve body 50.
Pg can be output to the first signal oil passage ₄₇₁ .

Further, from the hydraulic oil passage 43, a throttle valve
An inlet oil passage 53 connected to the input port of the valve Vt branches, and a second signal oil passage 4 is connected to the output port of the valve Vt.
7 ₂ extends. A modulator valve 54 is interposed in the middle of the inlet oil passage 53 to define an upper limit value of the inlet pressure of the throttle valve Vt.

The throttle valve Vt is of a known type, and includes a spool valve body 55 and a control spring 5 that presses the valve body 55 to the left.
8. A return spring 57 that presses the valve body 55 to the right;
Control piston 5 bearing the outer end of control spring 58
9. A control cam 6 that rotates in conjunction with an increase in the opening of the throttle valve of the engine E and moves the control piston 59 to the left.
0, it has an adjustment bolt 61 etc. that can adjust the set load of the return spring 57. When the control piston 59 moves to the left, the displacement pushes the spool valve body 55 to the left via the control spring 58, but the hydraulic pressure output to the second signal oil passage ₄₇₂ due to this leftward movement pushes the spool valve body 55.
As a result, the throttle valve Vt applies oil pressure proportional to the throttle valve opening of the engine E, that is, the throttle pressure Pt, to the second signal oil path _472. It can be output.

The first and second signal oil passages 47 ₁ , 47 ₂ are pilot hydraulic chambers 62 , 62 ′ at both ends of the low-medium speed shift valve V ₁ and the medium-high speed shift valve V ₂ , respectively.
3' respectively. As a result, each of the spool valve bodies 64 and 65 of these shift valves V ₁ and V ₂ receives the governor pressure Pg and throttle pressure Pt on both end faces and is operated as follows.

That is, the spool valve body 6 of the low-medium speed shift valve _V1
4 is initially held at the rightward movement position shown in the figure by the force of the spring 66, but as the vehicle speed increases, the governor pressure Pg increases, and the left power of the spool valve body 64 due to this governor pressure Pg is increased by the throttle pressure Pt and the spring 66. 66, the click ball 68 that moves together with the valve body 64 in the click motion mechanism 67 provided at the right end of the valve body 64 overcomes the fixed positioning protrusion 69, and the click ball 68 moves over the fixed positioning protrusion 69. The valve body 64 quickly switches to the left-hand position, and the hydraulic pressure from the hydraulic pump P, which had previously been sent only to the hydraulic cylinder ₄₀₁ of the low gear clutch _C1 , is now transferred to the hydraulic oil passage 7.
It is also sent to the hydraulic cylinder ₄₀₂ of _the middle gear clutch _C2 through 0,71,412, and both clutches
Since C ₁ and C ₂ are in the connected state, the middle speed gear train G ₂ is established as described above.

As the vehicle speed increases further, the medium-high speed shift valve
A similar effect occurs in valve V ₂ , and the spool valve body 65 of the valve V ₂ moves to the left due to the increasing governor pressure Pg, opening the hydraulic oil passages 41 ₂ and 71 to the oil tank R, while passage 70, which in turn leads to the hydraulic oil passage 4 leading to the hydraulic cylinder ₄₀₃ of the high speed clutch _C3 .
1 to ₃ , the middle gear clutch _C2 is in the disconnected state, and the low gear clutch _C1 and the high gear clutch C2 are in the disconnected state.
C ₃ becomes connected and the high speed gear train G ₃ is established as described above.

In this way, as is well known, a shift map divided by solid lines in FIG. 3 can be drawn. In reality, the click motion mechanism 67 provided in each shift valve V ₁ , V ₂ results in a different speed change map during upshifting and downshifting, but this is well known and is not limited to the present invention. , since it does not have much meaning, only the map at the time of shift up is shown.

Shift manual valve Vm to a position other than drive position D, such as middle gear holding position or reverse position.
When shifting to Re, the intermediate speed gear train _G2 or the reverse gear train Gr are respectively established, but since this has no particularly important relation to the present invention, further explanation will be omitted. In addition, manual valve Vm
Among the shift positions, Pk indicates the parking position.

Hydraulic circuits as described above are conventionally known.

Now, the control valve device of the direct coupling clutch Cd of the present invention
Dc will be further explained with reference to FIG. The control valve device Dc in the illustrated example is a first embodiment, which is a pressure reducing valve.
It consists of Vd and vehicle speed responsive valve Vs.

The pressure reducing valve Vd includes a spool valve body 80 that moves between an open position on the right and a closed position on the left, and a spring 81 that presses the valve body 80 toward the open position.
Pilot hydraulic chamber 82 facing the right end surface of the valve body 80
and input and output ports 83 and 84, the input port 83 is connected to an oil passage 41 ₃ ' branched from the hydraulic oil passage 41 ₃ of the high speed clutch C ₃ , and the output port 84 is connected to an orifice 85. It is communicated with the pilot hydraulic chamber 82 via an output oil passage 86, and also with the hydraulic cylinder 14 of the direct coupling clutch Cd via an output oil passage 86. The valve body 80 is integrally equipped with a stopper rod 80a that prevents excessive deformation of the spring 81 by regulating the amount of movement of the valve body 80 toward the closing side to a constant level when the hydraulic pressure in the pilot hydraulic chamber 82 increases excessively. is formed.

The vehicle speed responsive valve Vs includes a spool valve body 87 that moves between a closed position on the right and an open position on the left, and a spring 88 that presses this valve body 87 toward the closed position.
and the pilot hydraulic chamber 8 facing the right end surface of the valve body 87.
9, a click motion mechanism 90 that provides a snap action to the valve body 87, and input and output ports 91, 9.
2. The click motion mechanism 90 is
Similar to the mechanism 67 provided in the low-medium speed shift valve _V1 , it consists of a click ball 93 that moves together with the spool valve body 87, and a fixed regulating plate 95 having a positioning projection 94. Therefore, the valve body 8
7 is normally held in the right closed position by the biasing force of the spring 88, but when the hydraulic pressure in the pilot hydraulic chamber 89 exceeds a specified value, the click ball 93
moves over the positioning protrusion 94 and rapidly moves to the left to the open position. Pilot hydraulic chamber 8
9 has an oil passage 47 ₁ ′ branched from the first signal oil passage 47 ₁ , the input port 91 has an oil passage 41 3 ′ similar to the input port 83 of the pressure reducing valve Vd, and the output port 92 has an oil passage 47 ₁ ′ branched from the first signal oil passage 47 1 . An output oil passage 86 is connected similarly to the output port 84 of the pressure reducing valve Vd. Thus, the pressure reducing valve
Vd and the vehicle speed responsive valve Vs are connected to an oil passage 41 ₃ ′ that connects a hydraulic oil passage 41 ₃ connected to a hydraulic pressure source and a direct coupling clutch Cd,
86 in parallel relationship.

Next, the operation of the control valve device Dc will be explained.

First, low speed gear train G ₁ or middle speed gear train G ₂
Considering the case where _the vehicle is running at a low speed due to the establishment _of
At least the hydraulic oil passage 41 ₃ of the high speed clutch C ₃
is connected to oil tank R, and governor valve Vg
Since the output oil pressure, that is, the governor pressure Pg, is relatively low, the pressure reducing valve Vd and the vehicle speed responsive valve Vs are both in the illustrated state, and the pressure inside the hydraulic cylinder 14 of the direct coupling clutch Cd is atmospheric pressure.

On the other hand, inside the torque converter T there is a throttle 33.
Since a part of the line pressure Pl is introduced through the clutch Cd, the piston 13 of the direct coupling clutch Cd is moved to the left by the internal pressure of the torque converter T and the piston 13 of the direct coupling clutch Cd is moved to the left by the internal pressure of the torque converter T.
has been released. Therefore, in the established state of the low-speed gear train _G1 or the middle-speed gear train _G2 , the torque converter T can fully demonstrate its original torque amplification function, so that acceleration operation can be performed smoothly. .

From this state, the vehicle speed increases and the high speed gear train _G3
When established, in this case, the high speed clutch C ₃ is supplied with hydraulic pressure from its hydraulic oil passage 41 ₃ and enters the operating state, so the hydraulic pressure is also transmitted to the pressure reducing valve Vd through the oil passage 41 ₃ ′, and its It passes through the input and output ports 83 and 84 and is supplied to the hydraulic cylinder 14 of the direct coupling clutch Cd via the output oil passage 86, and this hydraulic pressure moves the piston 13 to the right to close the clutch.
Start CD operation.

When the piston 13 moves to the right and the operation or connection of the direct coupling clutch Cd starts, the hydraulic cylinder 1
As the oil pressure in 4 increases, the pressure reducing valve
The oil pressure in the pilot oil pressure chamber 72 of Vd also rises, and when that oil pressure exceeds the specified value, the valve body 80 moves to the right and closes off between the output ports 83 and 84. suppresses the increase in bond strength. Thus, a weak connection region of the direct coupling clutch Cd is obtained as shown by the sand marks in FIG.

The coupling force of the direct coupling clutch Cd controlled in this way is strong enough to withstand the cruising output of the vehicle at that time and not slip, but it is strong enough to withstand the cruising output of the vehicle at that time, but it is strong enough to withstand the engine output when the accelerator pedal is pressed to the full throttle. , is set to a size that causes slippage. Therefore, as long as the vehicle is cruising at a constant speed,
As with conventional clutches that use a direct coupling clutch, economical, quiet, and non-slip operation is possible; on the other hand, when accelerating, the direct coupling clutch Cd slips appropriately to perform the aforementioned power split operation. Therefore, there is no feeling of insufficient output, which is common with conventional devices.

In addition, since the coupling force of the direct coupling clutch Cd is relatively weak, when the torque of the engine E fluctuates, the direct coupling clutch Cd also exerts a function of absorbing vibration by causing a slight slip even at the peak value of vibration. In particular, if a roller-type direct coupling clutch Cd as shown in the figure is adopted, all the reverse loads from the driving wheels W and W' are transmitted to the engine E only hydrodynamically by the torque converter T due to its one-way clutch action. Therefore, the vibration energy is substantially half-wave rectified, thereby ensuring smoother operation.

When the vehicle speed further increases and exceeds the specified value vo, the oil passage 47 is connected to the pilot hydraulic chamber 89 of the vehicle speed response valve Vs.
Since the governor pressure Pg introduced through ₁ ' reaches the specified operating pressure and moves the valve body 87 to the left, the input port 91 and the output port 92 are communicated, and the pressure reducing valve
Vd becomes short-circuited. Therefore, the working hydraulic pressure of the high speed clutch _C3 is supplied to the hydraulic cylinder 14 of the direct coupling clutch Cd without being reduced in any way.
As a result, the direct coupling clutch shown with diagonal lines in Figure 3
A strong connection region of Cd is obtained. The coupling force of the direct coupling clutch Cd, which has been enhanced in this manner, sufficiently withstands the running resistance which increases in proportion to the square of the vehicle speed, and maintains the torque converter T in a directly coupled state without slippage.

In the above embodiment, the vehicle speed responsive valve Vs was configured to be hydraulically controlled using the governor pressure Pg as the pilot pressure, but the structure may be used as long as it responds to a specified vehicle speed.For example, it may be configured to electrically detect the specified vehicle speed. Various types can be adopted, such as one that opens and closes using the excitation force of a solenoid, and one that opens and closes using the centrifugal force of the turbine wheel 3 provided on the side of the turbine wheel 3 of the torque converter T.

FIG. 4 shows a second embodiment of the control valve device Dc of the present invention, in which the pressure reducing valve Vd of the previous embodiment is replaced with
A bypass 96 that bypasses the vehicle speed responsive valve Vs when it is in the closed state is connected to the oil passages 41 ₃ ′, 86, and a leak passage 97 is connected to the bypass 96, and an orifice is installed on the inlet side of these bypasses 96 and the leak passage 97. 98 and 99 are provided respectively, and the leak passage 97 is closed when the vehicle speed responsive valve Vs is opened, and the other construction is the same as that of the previous embodiment. Therefore, when the high-speed gear train _G3 is established and the vehicle speed is below the specified value _v0 , the vehicle speed responsive valve Vs remains closed as in the previous embodiment.
The hydraulic pressure of the high-speed clutch _C3 is transferred to the direct clutch through the oil passage ₄₁₃ ', the bypass 96 and the output oil passage 86.
It is supplied to the hydraulic cylinder 14 of Cd. that time,
The amount of pressure oil introduced into the bypass 96 is determined by the orifice 98.
At the same time, a part of the pressure oil that has passed through the orifice 98 is discharged to the oil tank R side through the orifice 99 of the leak passage 97, so that the working pressure of the high speed clutch _C3 is eventually reduced. is supplied to the hydraulic cylinder 14 in a reduced pressure state, and the direct coupling clutch Cd exerts a relatively weak coupling force.
When the vehicle speed exceeds the specified value v ₀ and the vehicle speed responsive valve Vs is opened, the valve body 87 opens the leak passage 97.
is closed, thereby preventing leakage loss of pressure oil and supplying the hydraulic pressure of the high speed clutch _C3 to the hydraulic cylinder 14 without being reduced in pressure through the vehicle speed responsive valve Vs, and the direct coupling clutch Cd exerts a strong coupling force. .

As described above, according to the present invention, the direct coupling clutch is configured to be hydraulically operated, and the oil passage connecting the hydraulic cylinder of the direct coupling clutch and the hydraulic oil passage that becomes high pressure when the high-speed gear train is established is provided with a specified pressure. At low speeds, the coupling force of the direct clutch is weakened so that the direct clutch and torque converter work together to transmit torque during acceleration, and at high speeds, the torque converter is directly coupled so that it transmits torque virtually independently. In order to strengthen the coupling force of the clutch, a control valve device is installed that controls the hydraulic pressure supplied from the oil passage to the hydraulic cylinder in two stages, high and low, so that when the low gear train is established, the direct coupling clutch is kept inactive. hold,
It is possible to fully utilize the torque amplification function of the torque converter and perform good acceleration operation. Also, when establishing a high-speed gear train, the direct coupling clutch is operated,
Since the coupling force of the direct coupling clutch is weak in the low speed range of the vehicle, during acceleration operation, the clutch is appropriately slipped to perform power split operation.As a result, the torque converter's slip loss is halved while maintaining its original torque amplification function. It is possible to perform powerful and economical acceleration operation by recovering the engine to a certain extent, and in response to the engine's large peak torque, the direct coupling clutch absorbs vibrations and shocks with appropriate slippage, allowing comfortable low-speed operation. Able to drive. On the other hand, in high vehicle speed ranges, the coupling force of the direct coupling clutch is strengthened to suppress slippage, resulting in quiet and economical operation, which can greatly contribute to reducing practical fuel consumption and improving driving performance as a whole.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a vehicle automatic transmission to which the present invention is applied, and FIG. 2 is a hydraulic control circuit diagram of the automatic transmission, including a first embodiment of the control valve device of the present invention.
Figure A is an exploded view of the main parts of the direct coupling clutch in Figure 2, Figure 3
The figure is a speed change characteristic diagram using the hydraulic circuit shown in FIG. 2, and FIG. 4 is a longitudinal sectional view showing a second embodiment of the control valve device of the present invention. Cd...Direct coupling clutch, Dc...Control valve device, Df
... Differential gear, E ... Engine, G ₁ ... Low speed gear train, G ₂ ... Middle speed gear train, G ₃ ... High speed gear train, M ... Auxiliary transmission, T ... Torque Converter, Vd...pressure reducing valve, Vs...vehicle speed responsive valve, W,
W′... Drive wheel, 1... Crankshaft, 2... Pump wheel, 3... Turbine wheel, 5... Input shaft,
6...Output shaft, 14...Hydraulic cylinder.

Claims (1)

[Scope of Claims] 1. A torque converter having an input member including a pump impeller and an output member including a turbine impeller, and a multi-stage gear train, through which the torque of the output member is transmitted to the drive wheels. provided between the auxiliary transmission to be transmitted and the input and output members, and having a sliding characteristic that operates to mechanically connect these two members when a predetermined high-speed gear train of the auxiliary transmission is established. In a vehicle automatic transmission equipped with a direct coupling clutch, the direct coupling clutch is configured to be hydraulically actuated, and a hydraulic cylinder thereof is connected to a hydraulic oil passage which becomes high pressure when the high speed gear train is established. In the oil passage, the coupling force of the direct coupling clutch is weakened so that the coupling force of the direct coupling clutch and the torque converter cooperate to transmit torque during acceleration operation in the low speed range after a specified vehicle speed, and the coupling force of the direct coupling clutch is weakened in the high speed range, and the torque converter is substantially reduced in the high speed range. For vehicles, the control valve device is interposed to control the hydraulic pressure supplied from the hydraulic oil passage to the hydraulic cylinder in two stages, high and low, so as to strengthen the coupling force of the direct coupling clutch so as to independently transmit torque. A direct control device for the torque converter in automatic transmissions. 2. In what is stated in claim 1,
The direct coupling clutch is of a type that increases the coupling force in accordance with an increase in the hydraulic pressure in the hydraulic cylinder, and the control valve device is configured to provide a pressure reducing device in the oil passage that closes when the hydraulic pressure in the hydraulic cylinder exceeds a specified value. A direct-coupled control device for a torque converter in an automatic transmission for a vehicle, comprising a valve and a vehicle speed-responsive valve that opens when the vehicle speed exceeds a specified value, which are interposed in parallel in the oil passage.