JP3123671B2 - Fluid coupling fastening force control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fastening force control device for a fluid coupling of an automatic transmission, and more particularly to a device for improving the accuracy of slip control and improving the reliability of lock-up fastening.

[0002]

2. Description of the Related Art Conventionally, a fluid coupling of a conventional automatic transmission for a vehicle is provided with a lock-up clutch, and a lock-up shift for switching supply of hydraulic pressure to an engagement oil chamber and a release oil chamber of the lock-up clutch. A valve and a lock-up control valve for controlling a differential pressure between the engagement oil chamber and the release oil chamber are provided, the lock-up state is set by setting the differential pressure to a maximum, and the differential pressure is set within a predetermined range. By doing so, the lock-up clutch is brought into a slip state, and the differential pressure is set to a minimum so as to be brought into a lock-up release state (for example, see Japanese Patent Application Laid-Open No. 2-120568).

[0003] Generally, in a steady operation in which the gear stage is not switched, the lock-up clutch is locked in a predetermined middle to high speed operation region, and an engine output speed is set in a predetermined low load and low speed operation region. The slip control is performed while controlling the differential pressure so that the difference between the rotation speed of the turbine and the rotation speed of the turbine is substantially constant. The lock-up control valve is configured to control its control pressure via a duty solenoid valve,
For example, in the conventional device, as shown by the differential pressure characteristic line Cp in FIG. 7 according to the embodiment, the control pressure decreases according to the increase in the duty ratio of the duty solenoid valve, and the differential pressure ΔP increases, The configuration is such that when the duty ratio D reaches 100%, the differential pressure ΔP becomes maximum and the lockup state is established.

[0004]

In the conventional device, the duty ratio D of the duty solenoid valve is one.
When the pressure reaches 00%, the differential pressure ΔP is maximized to be in a lock-up state.
Pressure, ie, the rate of change of the differential pressure ΔP (differential pressure characteristic line C
(slope of p) becomes large, so that it is difficult to precisely control the differential pressure ΔP when performing the slip control. SUMMARY OF THE INVENTION It is an object of the present invention to provide a fluid coupling fastening force control device capable of improving the accuracy of slip control and reliably performing a transition to a completely locked-up engagement state.

[0005]

According to a first aspect of the present invention, there is provided a fluid coupling engagement force control device for switching a hydraulic pressure supply to a coupling oil chamber and a release oil chamber of a lock-up clutch in a fluid coupling of an automatic transmission. A lock-up shift valve, a lock-up control valve for controlling a differential pressure between the engagement oil chamber and the release oil chamber, and a control pressure of the lock-up control valve when the control pressure is out of a predetermined differential pressure control range. to a lock valve for setting the pre-Symbol differential pressure to the maximum by the action of additional hydraulic pressure to the lock-up control valve, when setting the pressure difference to the maximum
A differential pressure change limiting means for gradually changing the differential pressure,

[0006] the drain port of the lockup control valve the hydraulic pre Symbol releasing oil chamber to a drain is connected to the lock valve via a drain oil passage, the differential pressure change limiting means comprises an orifice which is connected to the drain oil passage A drain port connected to the drain port of the lock valve when the control pressure is within the differential pressure control range, and a drain oil passage when the control pressure is out of the differential pressure control range. Is closed.

[0007]

According to the first aspect of the present invention, the lock-up shift valve switches between the supply of hydraulic pressure to the engagement oil chamber and the release oil chamber of the lock-up clutch, and the lock-up control valve includes: The lock valve receives a control pressure of a lock-up control valve, and controls an additional hydraulic pressure when the control pressure is out of a predetermined differential pressure control range. On the lock-up control valve to set the differential pressure to the maximum.

Therefore, the differential pressure characteristic of the lock-up control valve can be set so that the differential pressure gradually changes with respect to the control pressure, and the transition to complete lock-up is ensured to enhance the reliability of lock-up engagement. I can do it.

[0009] Then, when setting the differential pressure to the maximum, since there is provided the difference pressure change restriction means for causing gradual difference pressure change, it is possible to prevent the torque shock due to the lock-up engagement.

In addition, a drain port of a lock-up control valve for draining the hydraulic pressure of the release oil chamber is connected to the lock valve via a drain oil passage, and the differential pressure change limiting means is connected to an orifice connected to the drain oil passage. A drain port having a drain port connected to a drain port of the lock valve when the control pressure is within the differential pressure control range, and a drain oil when the control pressure is out of the differential pressure control range. Since the configuration is such that the road is closed, the differential pressure change limiting means can be operated by effectively utilizing the lock valve.

[0011]

According to the present invention as described in the paragraph of the effect, according to the engagement force control apparatus for a fluid coupling according to 請 Motomeko 1, provided with the lock-up shift valve, a lock-up control valve, and a lock valve As a result, the differential pressure characteristic of the lock-up control valve can be set so that the differential pressure changes gradually with respect to the control pressure, and the transition to complete lock-up is ensured to ensure the reliability of lock-up engagement. Can be done.

[0012] Then, by providing the gradual difference pressure change limiting means for causing a differential pressure change when setting the differential pressure to the maximum, it is possible to prevent the torque shock due to the lock-up engagement. In addition, the differential pressure change limiting means can be operated by effectively utilizing the lock valve.

[0013]

Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the output of the engine 1 is transmitted to drive wheels via an automatic transmission AT including a torque converter 2 (fluid coupling), a main transmission 3 and an auxiliary transmission 4. As shown in FIG.
Includes a pump 20 connected to the engine output shaft 1a, a turbine 21 disposed opposite to the pump 20, and a stator 22 disposed between the pump 20 and the turbine 21.

The stator 22 includes a one-way clutch 23
Through a fixed shaft 24 integrated with the case 5 of the automatic transmission AT. The one-way clutch 23 allows the stator 22 to rotate in the same direction as the pump 20 and prohibits rotation in the opposite direction.

The turbine 21 has a torque converter 2
Output shaft 2a is coupled to the output shaft 2a and the pump 20.
Is provided between the lock-up clutch 25 and the lock-up clutch 25. The lock-up clutch 25 is connected to the torque converter 2
It is constantly urged in the clutch engagement direction (lock-up direction) by the hydraulic pressure of the hydraulic oil circulating inside, and at the same time, is held in the open state by the release hydraulic pressure supplied from the outside. The shaft 1a and the converter output shaft 2a are configured to be directly locked up. The hydraulic system of the lock-up clutch 25 will be described in detail later in this embodiment.

The main transmission 3 will be described. The main transmission 3 includes a front planetary gear mechanism 3A and a rear planetary gear mechanism 3A.
B, and the front-stage planetary gear mechanism 3A includes a sun gear
32 , a pinion gear 31, a ring gear 30 , and a planetary carrier 34. The rear planetary gear mechanism 3B includes a sun gear 37 , a pinion gear 3
6 and a ring gear 35 , and a planetary carrier 38. The carrier 34 and phosphorus
Grayed gear 35 and is coupled, also be bonded and the ring gear 30 and carrier 38, carrier 38 is coupled to an output shaft 3a of the main transmission 3.

[0017] The converter output shaft 2a, the second with are combined with sun gear 32 via the first clutch K1
It is coupled with sun gear 37 via the clutch K2.
The main transmission 3 includes three brakes fixed to the case 5, a first brake B1, a second brake B2, and a third brake.
And the brakes B3, B2, B3 and the clutches K1, K2, which are frictional engagement elements.
It is configured to be able to achieve three forward speeds and one reverse speed by combining the disengaged states, and in addition, one-way clutches OWC1 and OWC2 are also provided.

The auxiliary transmission 4 will be described. The auxiliary transmission 4 is constituted by a planetary gear mechanism comprising three gear elements, a sun gear 40, a pinion gear 41, a ring gear 42, and a planetary carrier 43. The input shaft 4a of the transmission 4 is connected to the output shaft 3a of the main transmission 3 via a gear 44, and the carrier 43 is connected to the output shaft 4b of the auxiliary transmission 4. . The auxiliary transmission 4 includes a brake B fixed to the case 5.
0, and the sun gear 40 and the ring gear 42 are coupled via the brake B0 and the clutch K0, and the high speed (H) and the low speed Stage (L), and in addition to these,
A one-way clutch OWC0 is also provided.

The automatic transmission AT includes brakes B1, B
2, B3, B0 and the combination of the engaged and released states of the clutches K1, K2, K0, as shown in FIG.
In addition to the first reverse speed, five forward speeds can be achieved, and a circle in the figure indicates a fastening operation. Further, the five forward gears and the gears of the main transmission 3 and the auxiliary transmission 4 are described below.
The relationship with the gear ratio is, for example, as shown in FIG.

Next, the hydraulic system of the lock-up clutch 25 of the toque converter 2 will be described. As shown in FIG. 5, the Le juicing valve 46 to depressurize the constant pressure receiving line pressure P _L, fastening oil chamber 26 of the lockup clutch 25 (the rear oil chamber) and a release oil chamber 27 (front oil chamber) A lock-up shift valve 90 for switching the supply of hydraulic pressure to the hydraulic pump, a lock-up control valve 100 for controlling the differential pressure between the fastening oil chamber 26 and the release oil chamber 27 via a duty solenoid valve 51, and a lock-up control valve 100 herewith unique lock valve 110 in order to lock, the oil cooler 86 which cools received by via the oil passage 84 and the check valve 85 the hydraulic oil in Tok Le converter 2, a cooler relief valve 87, the line pressure P _L an oil passage 58 for receiving, an oil passage 66 for receiving the converter pressure P _C, the other oil passage is provided as shown.

The oil passage 58 is provided with a filter 59 and a throttle valve 61.
Type solenoid valve 63 is connected, and with respect to the lock-up shift valve 90, the spool 91 has three lands, and the oil chamber 92 at the right end of the spool 91 has an oil passage 5.
The hydraulic pressure downstream of the throttle valve 61 of 8 is introduced through an oil passage 62, and the spool 91 is urged rightward by a spring 93. When the solenoid valve 63 to OFF, the lock-up shift valve 90 is in the state shown in the upper half portion, the oil passage 66 an oil passage 69 branched from the blocked, and the converter of the oil passage 66 pressure P _C is the oil passage 70 Then, the lock-up clutch 25 is introduced into the release oil chamber 27 through the oil passage 83 and maintained in the release state.

[0022] When the ON solenoid valve 63, the lock-up shift valve 90 is in the state shown in the lower half, the converter pressure P _C is supplied with the oil passage 69 and the oil passage 82 into the engagement oil chamber 26 communicates with The oil passage 70 is blocked, the oil passage 83 communicates with the oil passage 74, and the oil pressure in the release oil chamber 27 is discharged from the drain port 80 of the lock valve 110 via the lock-up control valve 100 and the drain oil passage 77. And the hydraulic pressure in the release oil chamber 27 basically becomes equal to the duty ratio D of the duty solenoid valve 51.
Becomes the oil pressure according to the control pressure of the oil passages 50 and 53 set in accordance with the control pressure. The lock-up control valve 100
The control pressure of an oil passage 50 connected to an oil passage 47 extending from a reducing valve 46 is introduced into an oil chamber 102 at the right end of the spool 101 via an oil passage 55 having a throttle valve 52. Is biased rightward by a spring 103, and the oil pressure in an oil passage 74 is introduced into a feedback oil chamber 105 via an oil passage 75 having a throttle valve 76.

Since the control pressure decreases in accordance with the increase in the duty ratio D, when the duty ratio D is 0%, the control pressure is high, and the spool 101 is in the state shown in the lower half, and the oil passage 74 and the drain Since the communication of the oil passage 77 is cut off, the pressure difference ΔP between the engagement oil chamber 26 and the release oil chamber 27 is minimized, and the lock-up clutch 25 maintains the release state. Since the control pressure supplied to the oil chamber 102 decreases as the duty ratio D increases, the spool 101 moves to the right according to the control pressure, and the communication between the oil passage 74 and the drain oil passage 77 In order to adjust the opening, the oil chamber of the release oil chamber 27 is lowered, and the pressure difference ΔP between the fastening oil chamber 26 and the release oil chamber 27 is set to a magnitude corresponding to the control pressure.

With respect to the lock valve 110, a spool 111 has three lands, and a control pressure is introduced into an oil chamber 112 at the right end of the spool 111 through an oil passage 53 having a throttle valve 54. Spring 1
13, and the duty ratio D is 0 to 0
When α% (α is a value of 85 to 95, for example), the control pressure is not sufficiently low, so that the spool 111 is maintained in the state shown in the upper half, the oil passage 60 is blocked, and the drain oil passage 77 is It is communicated with the drain port 80. On the other hand, when the duty ratio D becomes α%, the control pressure drops below a predetermined value, and the spool 111 is switched to the state shown in the lower half. As a result, the oil passage 60 becomes the oil passage 81
And the line pressure P _L of the oil passage 60 is connected to the oil chamber 1 at the left end of the lock-up control valve 100 via the oil passage 81.
04, the spool 101 is switched to the right limit position, the oil passage 74 and the drain oil passage 77 are completely connected, and the downstream end of the drain oil passage 77 is blocked by the land of the spool 111. Since the drain oil passage 77 is provided with a drain port 78 having an orifice 79, the oil pressure in the drain oil passage 77 is drained from the orifice 79 and the drain port 78.

When the orifice 79 is not provided,
With the switching of the lock valve 110, the oil pressure in the release oil chamber 27 sharply drops, and the differential pressure ΔP instantaneously becomes maximum.
By providing the orifice 79, the torque shock can be prevented by gradually increasing the differential pressure ΔP to the maximum. That is, the orifice 79 corresponds to a differential pressure change limiting unit. Incidentally, the oil passage 67 is an oil passage for the hydraulic supply of the deficiency in Teyuti control oil passage 68 is an oil passage Kyusuru hydraulic for generating oil pressure for compensating for variations of the converter pressure P _C, the code 49 Is a throttle valve, reference numerals 48 and 6
5 is a filter, and "x" mark in the figure is a drain port.

Next, the control unit 130 for controlling the automatic transmission AT will be described briefly. The control unit 130 receives, as an input signal, a first sensor 120 for detecting the rotation speed of the turbine output shaft 2a. A detection signal, a detection signal of the second sensor 121 for detecting the rotation speed of the output shaft 3a of the main transmission 3, and a third sensor 12 for detecting the rotation speed of the output shaft 4b of the subtransmission 4.
2, a detection signal TVO of a throttle opening sensor for detecting the opening of the throttle valve of the engine 1, and
A vehicle speed signal SD of a vehicle speed sensor, a shift signal SF detected by a plurality of switches provided on a shift lever, and various detection signals such as a brake switch are input.

From the control unit 130,
A drive signal and a drive pulse signal are supplied to a plurality of solenoid valves and linear solenoid valves of the hydraulic system of the main transmission 3 and the sub transmission 4, and to the solenoid valve 63 and the duty solenoid valve 51, respectively. The control unit 130 includes an A / D converter for A / D converting an input signal as necessary, a plurality of waveform shaping circuits, an input / output interface, a microcomputer, a plurality of drive circuits, and the like. ROM
A general shift map using the vehicle speed SD and the throttle opening TVO as parameters, a control program for shift control based on various input signals and the shift map, slip control and lock-up control accompanying the shift control Programs and the like are input and stored in advance. However, since the slip control and the lock-up control are also general controls, a detailed description thereof will be omitted. However, for reference, a lock-up area A in which the lock-up clutch 25 is engaged as shown in FIG. Is set in the medium-high speed operation area,
A slip control region B for performing slip control such that a difference between the output rotation speed of the engine 1 and the output shaft rotation speed of the turbine 21 has a substantially constant value is set to a low load and low speed operation region.

Next, the operation of the lock-up clutch 25 of the torque converter 2 of the automatic transmission described above and the hydraulic system thereof will be supplementarily described. As shown in FIG. 7, when the solenoid valve 63 attached to the lock-up shift valve 90 is OFF, the converter pressure P is applied to the release oil chamber 27.
_{Since C} is supplied, the differential pressure ΔP is minimized, and the lock-up clutch 25 is maintained in the released state. On the contrary,
When the solenoid valve 63 is ON, the control pressure increases in accordance with the increase in the duty ratio D of the duty solenoid valve 51, and the differential pressure ΔP increases. The lock valve 110 switches as shown in FIG.
The line pressure P _L is supplied to the oil chamber 104 of the oil tank 104, so that the lock-up control valve 100 is switched to the position where the differential pressure ΔP is maximum, and at the same time, the oil pressure in the oil passage 77 gradually drains through the orifice 79 Therefore, the characteristic line C of the differential pressure ΔP is as shown in the figure. Therefore, it is possible to prevent torque shock when switching to the lock-up state when the duty ratio D is α%.

Further, as in the conventional device, the lock valve 1
A characteristic line Cp of the differential pressure ΔP when the duty ratio D is in the lock-up state at a value in the range of 100% or more without providing 10 is as shown in FIG. C has a gentler gradient than the characteristic line Cp of the differential pressure ΔP of the conventional device, and the rate of change of the differential pressure ΔP with respect to the duty ratio D becomes smaller. .

In addition, when the duty ratio D is equal to or more than α%, it is possible to reliably switch to the lock-up state and maintain the lock-up state, so that the reliability of lock-up engagement can be ensured. The range where the duty ratio D is 0 to α% corresponds to a predetermined differential pressure control range. When the duty ratio D (that is, the control pressure) deviates from the predetermined differential pressure control range, the lock valve The differential pressure ΔP is set to the maximum value via 110. still,
When the orifice 79 is not provided, the differential pressure ΔP changes to the maximum value according to the characteristic shown by the dotted line Ca in FIG. 7, but this case is not preferable because a sudden change in the engagement force of the lock-up clutch 25 causes a torque shock. .

In this embodiment, the main transmission 3 and the sub transmission 4
The embodiment in which the present invention is applied to the automatic transmission AT having the above has been described. However, the present invention is also applicable to a hydraulic system of a lock-up clutch of a torque converter of a normal automatic transmission having a set of transmissions. It goes without saying that the present invention is equally applicable. Further, as the lock valve 110, various structures other than those of the above-described embodiment can be applied without departing from the technical idea of the present invention.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an automatic transmission connected to an engine according to an embodiment of the present invention .

FIG. 2 is an overall configuration diagram of a mechanical configuration of the automatic transmission.

FIG. 3 is a table showing a relationship between a shift speed of the automatic transmission and an engagement pattern.

FIG. 4 is a table showing the gear positions of the automatic transmission, the gear positions of the main and auxiliary transmissions, and the gear ratios.

FIG. 5 is a hydraulic system diagram of a lock-up clutch of the automatic transmission.

FIG. 6 is an explanatory diagram of the lock-up region and the slip control region.

FIG. 7 is a characteristic diagram of a differential pressure of the lock-up clutch.

[Explanation of symbols]

 AT automatic transmission 25 lock-up clutch 26 engagement oil chamber 27 release oil chamber 51 duty solenoid valve 63 solenoid valve 77 drain oil passage 78 drain port 79 orifice 80 drain port 90 lock-up shift valve 100 lock-up control valve 110 lock valve

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16H 61/14

Claims (1)

(57) [Claims] 1. A fluid coupling for an automatic transmission, comprising: a lock-up shift valve for switching hydraulic pressure supply to a engagement oil chamber and a release oil chamber of a lock-up clutch; and a differential pressure between the engagement oil chamber and the release oil chamber. A lock-up control valve for controlling, and when the control pressure of the lock-up control valve is out of a predetermined differential pressure control range, an additional hydraulic pressure is applied to the lock-up control valve.
Gradually made a lock valve for setting the pre-Symbol differential pressure to the maximum, the differential pressure changes when setting the differential pressure to the maximum Te
A lock-up controller for draining the oil pressure in the release oil chamber.
The drain port of the roll valve locks through the drain oil passage.
And the differential pressure change limiting means is connected to a drain oil
Drain port with orifice connected to road
The lock valve is configured such that the control pressure is within the differential pressure control range.
The drain oil passage to the drain port of the lock valve
Connected and the control pressure is out of the differential pressure control range.
Is a closing force control device for a fluid coupling , which is configured to close a drain oil passage .