JPS6240201Y2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Technical Field The present invention relates to a slip control device for a lock-up torque converter used in automatic transmissions and the like.

(2) Prior art A lock-up torque converter rotates an output element (usually a turbine runner) while increasing its torque under the reaction force of a stator by stirring hydraulic oil from an input element (usually a pump impeller) driven by an engine. Operation mode (converter status)
There are two types of operation modes: (lock-up state) where the input/output elements are directly connected by coupling the lock-up clutch and the rotation toward the input element is extracted as is (lock-up state), and engine torque fluctuation becomes a problem and torque increase. The former operating mode is used in a relatively low engine speed range where this is necessary, and the latter operating mode is used in other high engine speed ranges. Therefore, lock-up torque converters can improve engine fuel efficiency by eliminating slip between input and output elements in the high engine speed range (high vehicle speed range), compared to normal torque converters that only have the former operating mode. It is now being put into practical use in many automobiles.

By the way, conventional lock-up torque converters only selectively use the above two types of operation modes, so the lock-up vehicle speed, which is the criterion for this judgment, is set to a fairly high vehicle speed at which engine torque fluctuations are small enough not to vibrate the vehicle body. I have no choice but to
The reality is that the lock-up period becomes shorter and a sufficient effect of improving fuel efficiency cannot be achieved.

Therefore, although engine torque fluctuations may be a slight problem, the lock-up clutch is engaged while slipping in a low rotation range where the torque is sufficient, thereby absorbing the engine torque fluctuations so that they do not become a problem and increasing the torque converter. The applicant of the present application had previously proposed a slip control device for a lock-up torque converter which suppresses slip and eliminates the above-mentioned problem in Japanese Patent Application No. 196897-1987.

This technology uses a conventional lock-up torque converter, that is, a torque converter input/output element, and a lock-up clutch that responds to the pressure difference between the converter chamber and the lock-up control chamber and directly transmits the rotation of the torque converter input element to the torque converter output shaft. The following features have been added to the lock-up torque converter included. That is, by slidably fitting the torque converter output element onto the torque converter output shaft and defining a pressure chamber between the two for guiding the pressure of the lockup control chamber, the torque converter output element is adjusted to the axis according to the pressure difference. Allows for direction movement. The torque converter output element is drive-coupled to the torque converter output shaft via a cam mechanism so as to rotate relative to the torque converter output element and move in the axial direction according to the difference between the generated torque and the transmission torque of the lock-up clutch. A variable orifice is provided that changes the degree of opening by moving in the direction to adjust the degree of communication between the converter chamber and the lockup control chamber.

According to this configuration, the pressure inside the converter chamber is led to the lockup control chamber through the variable orifice, and the pressure inside the lockup control chamber, that is, the coupling force of the lockup clutch is adjusted by the opening degree of the variable orifice. Since the opening degree can be changed in accordance with the torque generated by the torque converter output element, the lock-up torque converter can be slip-controlled so as to maintain a constant ratio between the torque of the lock-up clutch and the torque of the torque converter output element.

However, in such a configuration, liquid leakage occurs at the slidable fitting part between the torque converter output element and the torque converter output shaft, and the pressure in the converter chamber on the high pressure side leaks into the pressure chamber on the low pressure side, resulting in lock-up control. It is difficult to avoid inaccurate control of the pressure in the chamber. In other words, during the period from when the variable orifice changes from fully closed to fully open, the pressure P _L in the lockup control chamber is originally indicated by the dashed line a in FIG.
However, due to the pressure leak, the pressure changes as shown by the solid line b in the figure. Now, assuming that the range of pressure P _L for performing slip control is as shown by P _A in Fig. 10, the P _L change characteristic shown by solid line b has a change width ΔP' that is considerably smaller than the normal change width ΔP. Therefore, the pressure range P _A cannot be accommodated, slip control can only be performed under some operating conditions, and the control is inaccurate. In addition, under other operating conditions, the pressure P _L
is high, and the amount of slip is excessive or almost converts.

Furthermore, even if an attempt is made to reduce the pressure P _L to zero when placing the torque converter in the lock-up state, residual pressure will be generated in the lock-up control chamber due to the pressure leak, making it impossible to completely bring the torque converter into the lock-up state. Situations even occur.

These trends become even more pronounced as the temperature of the torque converter working fluid increases and its viscosity decreases, as pressure leaks become more frequent.

In order to solve the above problem, it is possible to reduce pressure leakage by processing the above-mentioned slidable fitting portion with high precision. However, in order to define a pressure chamber, it is necessary to have two slidable fitting parts, and in this case it is necessary to machine the diameters at two locations with high dimensional accuracy. It is extremely difficult to ensure highly accurate coaxiality and roundness.

In addition, the diameter of the outer slidable fitting part is quite large, so even if the dimensional accuracy is increased as much as possible, pressure leakage will occur beyond a certain level, making it impossible to hope for a sufficient solution to the problem. . Furthermore, if the dimensional accuracy of the fitting portion is increased, new problems such as the occurrence of stuck portions in the fitting portion cannot be avoided.

(3) Purpose of the invention The present invention aims to solve the above-mentioned problem by reducing the pressure leakage in the sliding fitting part to a small level that hardly becomes a problem, without increasing the dimensional accuracy of the sliding fitting part. purpose.

(4) Structure of the invention For this purpose, the slip control device of the present invention is applied to the lock-up torque converter of the above type.
The torque converter output element and the torque converter output shaft are characterized in that a sealing means is provided at the slidable fitting portion between the torque converter output element and the torque converter output shaft.

(5) Embodiments Hereinafter, the present invention will be explained 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 torque converter, and the torque converter 1 has a pump impeller (torque converter input element) 2 and a turbine runner (torque converter output element) 3. It mainly consists of a stator 4 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 has rivets 8 on its inner peripheral edge.
The turbine runner 3 is slidably fitted onto a sleeve 10 via which the turbine hub 9 is riveted, and the sleeve 10 is splined to the torque converter output shaft 11 so as not to move in the axial direction. It forms part of the output shaft 11. Flanges 9a and 10a facing each other and extending radially outward are integrally formed on the turbine hub 9 and sleeve 10, respectively, and these flanges are slidably fitted into each other to form a pressure chamber between them. 12. Ball grooves 13 are provided on the opposing surfaces of the flanges 9a and 10a, respectively.
14, and these ball grooves 13 and 14 extend along an arc of radius R centered on the torque converter output shaft 11, and are opposed to each other. Furthermore, the bottom surfaces 13a, 1 of the ball grooves 13, 14
4a are parallel to each other, but as shown in FIG.
These ball groove bottom surfaces 13 are tilted by an angle of
A cam mechanism is configured to sandwich one common ball 15 between ball grooves 13 and 14 by interposing it between a and 14a.

A lock-up clutch 16 is separately slidably fitted onto the sleeve 10, and the lock-up clutch 16 has an outer peripheral portion of the clutch facing 16a.
A lock-up control chamber 18 isolated from the converter chamber 17 is created during the time when the converter cover 5 is pressed into contact with the converter cover 5. Lockup control room 1
8 is constantly communicated with the pressure chamber 12 through holes 10b and 10c formed in the sleeve 10, and communicated with the converter chamber 17 through holes 10b and 10d in the sleeve 10 and an axial slit 9b formed in the turbine hub 9. Note that the slit 9b and hole 1
0d constitutes a variable orifice 19 whose opening indicated by diagonal lines in FIG. 6 is changed depending on the amount of overlap, and the variable orifice adjusts the degree of communication between the converter chamber 17 and the lock-up control chamber 18 according to the opening. . It is also possible to form an orifice in the hole 10c in order to improve steady stability when feeding back the hydraulic pressure in the lockup control chamber 18 to the pressure chamber 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 the lock-up clutch 16 is fixed by meshing the teeth 20a formed on the free end edge of the annular member 20 with the teeth 10e formed on the outer peripheral edge of the flange 10a. It is drivingly coupled to the sleeve 10 for relative axial movement.

The stator 4 of the torque converter 1 is placed on a hollow fixed shaft 22 via a one-way clamp 21, and annular passages 23, 2 are provided between the shaft 22, the pump drive shaft 6, and the torque converter output shaft 11, respectively.
Set 4. The annular passage 23 guides the hydraulic oil from the oil pump 7 into the torque converter 1, and the annular passage 24 removes this hydraulic oil. 1, that is, the inside of the converter chamber 17, is maintained at a constant pressure Pc.

The lock-up control chamber 18 is connected to a communication port 25a of a lock-up control valve 25 through a hollow hole 11a of the torque converter output shaft 11, and this control valve is composed of a spool 25b, a plug 25c, and springs 25d, 25e which urge these rightward in the drawing. The lock-up control valve 25 has a spool 25b which is moved in response to a governor pressure P _G corresponding to the vehicle speed which is supplied to a chamber 25f, and functions to selectively communicate the communication port 25a with an inlet port 25g, a drain port 25h with a fixed orifice 26, or a drain port 25i, and the converter chamber pressure Pc is introduced to the inlet port 25g.

In the present invention, as shown in FIGS. 1, 7, and 8, a seal ring 27 and an O-ring 28 are provided at the slidable fitting portion of the turbine hub 9 and the sleeve 10. Seal any liquid leaks. As clearly shown in FIG. 7, the seal ring 27 is engaged with the outer circumferential groove 29 of the flange 9a, and its outer circumferential surface is brought into sliding contact with the corresponding inner circumferential surface of the flange 10a.
As clearly shown in FIG. 8, the O-ring 28 is brought into sliding contact with the inner circumferential surface of the turbine hub 9 by engaging grooves 30 formed on the outer circumferential surface of the sleeve 10 on which the turbine hub 9 slides.

Although the seal ring 27 and the O-ring 28 are used as sealing means in this example, other sealing materials may be used as long as they prevent pressure leakage from the converter chamber 17 to the pressure chamber 12.

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

The vehicle speed is low, for example V ₁ (20km/h) in Figure 9.
In the following converter region A, the corresponding governor pressure P _G cannot push the spool 25b against the spring 25d, and the lock-up control valve 25 maintains the state shown in FIGS. 1 and 3. In this case, converter chamber pressure Pc is at ports 25g, 25a and hollow hole 11a
is supplied to the lockup control chamber 18 through the converter chamber 17, and this chamber 18 is made to have the same pressure as the converter chamber 17.
The lock-up clutch 16 remains in the released position shown in FIG. 1, operating the lock-up torque converter in the converter condition. That is, the engine-driven pump impeller 2 directs hydraulic oil to the turbine runner 3, which then returns to the pump impeller 2 via the stator 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.

On the other hand, when the vehicle speed is high, for example V ₂ (60
Km/h) or more, the corresponding high governor pressure P _G can push the spool 25b not only against the spring 25d but also against the spring 25e, thereby controlling the lock-up. valve 25
is in the state shown in FIG. In this case, the lock-up control chamber 18 communicates with the hollow hole 11a, the port 25a, and the drain ports 25h, 25i, and is maintained in an unpressurized state, so that the lock-up clutch 16 is moved to the left in FIG. 1 by the converter chamber pressure Pc. The lock-up torque converter is operated in the lock-up state by maintaining the joint position in which the clutch facing 16a is pressed against the converter cover 5. That is, the engine rotation directed toward the pump impeller 2 does not pass through the torque converter 1, but passes through the lock-up clutch 16, the annular member 20, and the sleeve 10, and is directly extracted from the torque converter output shaft 11, thereby making the slip ratio e of the torque converter zero. It can be done.

When the vehicle speed is in the slip region B between _V1 and _V2 in FIG. 9, the corresponding governor pressure P _G brings the lock-up control valve 25 into the state shown in FIG. 2. In this case, the pressure P in the lockup control chamber 18
_L is extracted through the fixed orifice 26, while
It receives replenishment of pressure P _C from the converter chamber 17 via a variable orifice 19 . During this time, the pressure P _L in the lock-up control chamber 18 is determined by the opening degree of the variable orifice 19, and the lock-up clutch 16 slides and frictionally engages the converter cover 5 to a degree corresponding to this pressure P _L , and the converter Power is transmitted in an intermediate state between the lock-up state and the lock-up state.

Here, considering the force acting on the turbine hub 9, the frictional force between it and the ball 15 is slight, so if this is ignored, the turbine hub 9 has a generated torque as shown in FIG. The force F _T due to T T _and the force F _L generated by the pressure difference between the converter chamber pressure P _C and the lockup control chamber pressure P _L acting on the pressure receiving area S of the turbine hub 9 within the chamber 12 are added, and the ball 15 is It has a drag force N that balances the resultant force of these forces. By the way, the above F _T and F _L are respectively F _T =
T _T /R,...(1), F _L = (P _C - P _L ) x S... (2), and in the above equilibrium state, F _T and F _L are respectively F _T =
Since it is also expressed as Nsinθ, F _L = Ncosθ, F _L
The relational expression tanθ=F _T (3) is found.

The transmission torque T _L of the lockup clutch 16 is expressed by the formula T _L = K (P _C - P _L ) (4), where K is a constant determined by its pressure receiving area and radius. From the above equations (1) to (3), T _L ×S/Ktan θ=T _T /R can be found, and as a result, between T _L and T _T , T _L = K/S × 1/Rtan θ × T The relational expression of _T is established. In this formula, K, S, R, θ
is a fixed value, so K/S×1/Rtanθ in the above equation is a constant, and if this is replaced with k, the above equation becomes T _L =k×T _T (5).

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

When the turbine torque T _T increases from this balanced state, the ball 15 is moved downward in FIG. 5, 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. be done. This axial movement displaces the slit 9b in the direction of the dotted arrow in FIG. 6, thereby reducing the opening degree of the variable orifice 19. As a result, the pressure from the converter chamber 17 to the lockup control chamber 18 via this variable orifice 19 is reduced, while from the lockup control chamber 18 to the fixed orifice 2
Since the pressure removed through step 6 is constant as described above, the pressure inside the lockup control chamber 18 is reduced so that the relationship of equation (5) is satisfied.

Conversely, from the above equilibrium state, the turbine torque T _T
When becomes smaller, the ball 15 is moved upward in FIG. 5, causing the turbine hub 9 to move axially to the left in the figure. This axial movement displaces the slit 9b in the direction of the solid arrow in FIG. 6, increasing the opening degree of the variable orifice 19. As a result, the pressure from the converter chamber 17 toward the lockup 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,
By moving the balls 15 constituting the cam mechanism in the axial direction of the converter, the adverse effects of centrifugal force on control etc. can be minimized.

By repeating this action, in the slip region shown by B in FIG. 9, the pressure in the lock-up control chamber 18, that is, the sliding coupling force of the lock-up clutch 16, is controlled by controlling the opening of the variable orifice 19 according to changes in the turbine _{torque T.} The lock-up torque converter can be slip-controlled 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 equation (5). The slip rate e of the torque converter in this slip region B is given by the above (5).
If k in the equation is designed to be 1/9, it will change continuously as shown in Figure 7, for example (e =
0.1, e=0.06, etc. are representative examples of slip ratios), and the slip ratio can be controlled to always be an appropriate value corresponding to the operating state of the engine.

By the way, in this example, sealing means 27 and 28 are provided at the slidable fitting portion between the turbine hub 9 and the sleeve 10 to prevent pressure leakage from the converter chamber 17 to the pressure chamber 12. The pressure inside the lockup control chamber 18 can be controlled as described above without causing any change in the pressure P _L . Therefore, the change characteristic of the pressure P _L with respect to the opening degree of the variable orifice 19 is shown by the dashed dotted line a in FIG.
The desired result is achieved as shown in , and the pressure change width Δ
P can be made sufficiently large. Because of this, the pressure change width Δ
P can cover the pressure range P _A in which slip control should be performed, and slip control can be accurately performed as intended under any conditions.

Further, since there is almost no pressure leakage to the pressure chamber 12, no residual pressure is generated in the lockup control chamber 18 in the lockup region, and a lockup state can be reliably obtained.

(6) Effects of the invention As described above, the slip control device of the present invention has a torque converter output element (turbine hub 9 in the illustrated example) and a torque converter output shaft 11.
(In the illustrated example, the sleeve 1 configured as a part of the
0) sealing means 27, 2 at the slidable fitting portion between
8, it is possible to almost eliminate pressure leakage from the converter chamber 17 to the pressure chamber 12, which prevents the pressure P _L from becoming inaccurately controlled and its change range ΔP from becoming small, thereby making it possible to control the pressure P L accurately. It is possible to perform accurate slip control.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional side view of a lock-up torque converter equipped with the slip control device of the present invention, FIGS. 2 to 4 are explanatory diagrams of the functions related to the lock-up control valve of the same torque converter, and FIG. 5 is the same as that shown in FIG. 1. Figure 6 is a developed cross-sectional view on the - line of Figure 1.
7 and 8 are respectively enlarged cross-sectional views of the main parts of the present invention, and FIG. 9 is a slip rate change characteristic diagram of the lock-up torque converter shown in FIG. 1.
FIG. 10 is a diagram showing the change characteristics of the lockup control pressure according to the device of the present invention in comparison with that according to the slip control device previously proposed by the applicant of the present invention. 1... Torque converter, 2... Pump impeller (torque converter input element), 3... Turbine runner (torque converter output element), 4...
Stator, 5... Converter cover, 9... Turbine hub, 9a... Hub flange, 9b... Axial slit, 10... Sleeve, 10a... Sleeve flange, 10b, 10c, 10d... Hole,
10e...Teeth, 11...Torque converter output shaft, 12...Pressure chamber, 13, 14...Ball groove (cam mechanism), 13a, 14b...Ball groove bottom (cam mechanism), 15...Ball (cam mechanism), 17
...Converter chamber, 18...Lockup control room, 19...Variable orifice, 20...Annular member, 20a...Teeth, 21...One-way clutch, 2
2... Hollow fixed shaft, 25... Lock-up control valve, 26... Fixed orifice, 27... Seal ring (sealing means), 28... O-ring (sealing means), 29, 30... Groove.

Claims (1)

[Scope of utility model registration request] It includes a torque converter input/output element, and a lockup clutch that directly transmits the rotation of the torque converter input element to the torque converter output shaft in response to the pressure difference between the converter chamber and the lockup control chamber, and connects the torque converter output element to the torque converter output shaft. The torque converter output element can be moved in the axial direction according to the pressure difference by being slidably fitted to define a pressure chamber between the two for guiding the pressure of the lockup control chamber. The element is drive-coupled to the torque converter output shaft via a cam mechanism so as to rotate relative to each other and move in the axial direction according to the difference between the generated torque and the transmission torque of the lock-up clutch, and the opening degree is changed by the axial movement of the torque converter output element. In a lock-up torque converter provided with a variable orifice that changes to adjust the degree of communication between the converter chamber and the lock-up control chamber, a sealing means is provided in a slidable fitting portion between the torque converter output element and the torque converter output shaft. A slip control device for a lock-up torque converter.