JP2002266996A - Hydraulic control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve both reduction in D-N shift shock and elimination of degradation of N-D shift response and shift feel. SOLUTION: This oil hydraulic control device for automatic transmission includes an accumulator 5 in feed oil passages La-Lc of a oil hydraulic servo 2 for operating a clutch C-1. A control valve 6 for controlling oil feed to the hydraulic servo, is inserted on the lower side than a portion connected to the accumulator. This makes the control valve and the accumulator lie in parallel with the feed oil passage, and the accumulator lie on the upper stream side of the feed passage to the control valve (lower stream side in the case of discharge), thereby achieving both quick feed to the hydraulic servo without being affected by the accumulated pressure in the accumulator and show relieving of servo hydraulic pressure using the discharge pressure from the accumulator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission, and more particularly to a hydraulic control for a starting engagement element.

[0002]

2. Description of the Related Art An automatic transmission is configured to transmit power by connecting an input shaft connected to a torque converter thereof to a transmission mechanism by engaging a clutch, and a clutch is provided with a hydraulic control device for a hydraulic servo. Engages with the supply of hydraulic pressure. In such an automatic transmission, the clutch engaged when the vehicle starts moving is shifted by a driver from an N (neutral) range to a D (drive) range (hereinafter referred to as N-drive).
Operation (referred to as D shift)
It is released by a shift to range (also referred to as DN shift) operation. At the time of this DN shift, the engine torque which has been transmitted to the wheels of the vehicle via the torque converter and the speed change mechanism by the engagement of the clutch up to that time is:
The transmission is suddenly stopped by releasing the clutch,
Shock occurs due to torque release. The shock generated in this manner is particularly remarkable in a gear train in which the starting gear is set to low geared. Conventionally, in order to reduce the DN shift shock, in a hydraulic supply circuit for a hydraulic servo of a starting clutch in a hydraulic control device, an accumulator is provided in series with the valve at the most downstream side of the valve for controlling hydraulic supply. Is provided.

[0003]

By the way, when the accumulator is arranged as described above, a pressure accumulating action on the accumulator occurs during the ND shift on the downstream side of the valve that controls the supply of hydraulic pressure to the hydraulic servo of the clutch. Therefore, the clutch engagement response at the time of the ND shift decreases. Further, this clutch is not a clutch that is always engaged to achieve all shift speeds from the start, but is disengaged halfway in relation to the speed change mechanism, and is engaged to operate to achieve a specific shift speed. In the case of a clutch, the controllability, which is an advantage of the direct control by the valve for controlling the hydraulic pressure supply to the clutch, is impaired, and the shift response and the shift feel are deteriorated.

[0004] The present invention has been devised in view of the above circumstances, and when an accumulator is provided in a hydraulic supply circuit to reduce a DN shift shock, an ND is required.
It is an object of the present invention to provide a hydraulic control device for an automatic transmission, which is capable of eliminating deterioration of response and shift feel during shifting and shifting.

[0005]

According to the present invention, there is provided a hydraulic control device for an automatic transmission in which an accumulator is connected to a supply oil passage of a hydraulic servo for operating an engaging element. A control valve for controlling the supply of hydraulic pressure to the hydraulic servo is interposed downstream of the connection portion of the supply oil passage.

In the above arrangement, it is effective that the control valve is constituted by a pressure regulating valve capable of controlling communication of a supply oil passage and a drain of a hydraulic servo.

In the above configuration, a bypass circuit bypassing the control valve, a communication of the supply oil path downstream of the control valve and a cutoff of the bypass circuit, and a cutoff of the supply oil path and a bypass circuit in the supply oil path. It is more effective if a switching valve for switching the communication is provided.

In the above configuration, it is also effective to provide a solenoid valve for applying a signal pressure to the control valve in order to operate the control valve at a signal pressure.

In the above arrangement, it is more effective to provide a solenoid valve for applying a signal pressure to the control valve and the switching valve in order to operate the control valve and the switching valve in relation to each other.

[0010]

According to the first aspect of the present invention, when the hydraulic pressure is discharged from the hydraulic servo, the discharge pressure due to the accumulated pressure of the accumulator acts on the upstream side (downstream side during discharge) of the control valve. Slow hydraulic discharge is performed using this. In addition, when hydraulic pressure is supplied to the hydraulic servo, the supply of hydraulic pressure to the hydraulic servo is controlled by a control valve located downstream from the connection of the accumulator on the supply oil path, so that the hydraulic servo is supplied regardless of the accumulator accumulation condition. A supply of hydraulic pressure is provided. Therefore,
According to this configuration, reduction of the DN shift shock and N
-Improve the response at the time of the D shift and reduce the shift shock. In addition, when the engagement element is used for achieving a specific shift speed, deterioration of shift shock can be prevented by improving controllability.

Next, according to the second aspect of the present invention, it is possible to drain the servo hydraulic pressure of the hydraulic servo by the control valve downstream of the accumulator (upstream at the time of discharge), so that the hydraulic pressure can be drained as needed during the D-N shift. Quick drain is also possible.

Next, according to the configuration of the third aspect, the characteristic of supplying hydraulic pressure to the hydraulic servo and the characteristic of discharging hydraulic pressure from the hydraulic servo can be freely controlled by operating the control valve and the switching valve.

Next, according to the configuration of the fourth aspect, the supply and discharge characteristics of the hydraulic servo can be freely controlled by controlling the control valve via the solenoid valve by an electric signal.

Next, according to the configuration of the fifth aspect, the control characteristic and the switching characteristic of the hydraulic servo can be freely controlled by electrically controlling the control valve and the switching valve through the solenoid valve by the electric signal.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a circuit configuration of a hydraulic control device according to a first embodiment of the present invention. In this circuit, a line pressure port (PL) is connected to a line pressure oil passage (not shown), and a manual valve 1 switched by a shift operation of a driver and a clutch C-1 as an engagement element not shown.
, And the D range port (D) of the manual valve 1 are connected to the hydraulic servo 2, and the hydraulic supply oil passages La, Lb, Lc in which the orifice 3 and the check ball 4 arranged in parallel are inserted in the middle. And an accumulator 5 connected to the hydraulic supply oil passage by an oil passage L1 on the downstream side Lb of the orifice 3 and the check ball 4, and a hydraulic supply oil passage Lb, Lc disposed downstream of the connection portion of the accumulator 5. A control valve 6 and a solenoid valve 7 provided to apply a signal pressure for controlling the control valve 6
And a solenoid modulator valve 8 for supplying a modulator pressure as a base pressure for outputting a signal pressure to the solenoid valve 7.

The manual valve 1 is a spool valve having seven positions. That is, the "P" position for closing the input port (PL) connected to the line pressure oil passage by the operation of the spool, the input port (PL) is connected to the R range output port (R), and the other output ports are drained. An "R" position for closing the input port (PL) with respect to all the output ports (the figure shows this "N" position) and an input port (P
L) communicates with the D range output port (D), the R range output port (R) is drained, and the second D range output port (D) is closed at the "D", "4", and "3" positions. And the input port (PL) is connected to both the D range output port and the second D range output port (D), and the R range output port (R) is drained.

A supply oil passage La for the hydraulic servo 2 of the clutch C-1 is connected to a D range output port and a second D range output port (D), and a signal from the electronic control unit is provided on the supply oil passage. Solenoid valve 7 that regulates pressure based on
And a control valve 6 in combination with a C1 solenoid valve. The C1 solenoid valve is a control valve 6 composed of a three-port type pressure regulating valve for controlling the degree of communication between the input / output ports 6a, 6b and the drain port 6d by a spool 60 loaded with a spring 61.
And a solenoid valve 7 composed of a 3-port linear solenoid valve to which a solenoid pressure is applied to the opposite end of the spool 60 on the side opposite to the spring load, and a solenoid 72 load and a spring load are applied oppositely.
The solenoid valve 7 has an input port 7a connected to the solenoid modulator valve 8 via a modulator pressure oil passage L2, and an output port 7b connected to the control valve 6.
Connected to the signal pressure port 6e. The control valve 6 has an input port 6a connected to the supply oil passage Lb, an output port 6b connected to the hydraulic servo 2 of the clutch C-1 via the supply oil passage Lc, and a feedback port communicating with the spool end on the spring 61 load side. 6c is connected via an orifice to a supply oil passage Lc downstream of the output port 6b.

The accumulator 5 is constituted by a piston-cylinder mechanism loaded with a spring, and a pressure accumulating chamber on the piston pressure receiving surface side is connected to an upstream supply oil passage Lb by an oil passage L1.

The supply circuit having such a configuration uses an oil pump (not shown) as a hydraulic pressure source and receives a supply of hydraulic pressure adjusted to a line pressure corresponding to the engine load by a primary regulator valve. This line pressure is regulated by a solenoid modulator valve 8 and supplied as a modulator pressure to an input port 7a of a solenoid valve 7, which is used as a base pressure of the solenoid pressure by the solenoid valve 7 and is also supplied to a manual valve 1. The supply pressure of the supply oil passage La is used.

The operation of the supply circuit configured as described above will be described. First, when an ND shift is performed to switch the manual valve 1 from the illustrated “N” position to the “D” position, the line pressure output from the D port to the supply oil passage La is started, and the check ball 4 is pushed open. Thus, hydraulic pressure is supplied from the supply oil passage Lb to the input port 6a of the control valve 6. At this time, the supply of the modulator pressure from the solenoid modulator valve 8 based on the line pressure causes the solenoid valve 7 to be in a state where the solenoid pressure can be output, and the driving of the linear solenoid 72 by a solenoid drive signal from an electronic control unit (not shown). The output of the solenoid pressure from the solenoid valve 7 is reduced in accordance with the control valve 6 which applies the solenoid pressure to the spool end.
Since the input port 6a and the output port 6b are in communication with each other, the hydraulic pressure is supplied to the hydraulic servo 2 via the supply oil passage Lc under the control of the control valve 6. On this occasion,
In the supply oil passage Lb on the upstream side of the control valve 6, pressure accumulation from the oil passage L1 to the accumulator 5 is also performed, but since the control valve 6 and the accumulator 5 are in a parallel relationship with respect to supply of line pressure, the accumulator 5 The pressure accumulation of
It does not affect the hydraulic pressure supply to the hydraulic servo 2. Thus, the clutch operated by the hydraulic servo 2 quickly engages under the control of the control valve 6.

Next, when the hydraulic pressure is supplied to the hydraulic servo 2 and the clutch C-1 is engaged, the manual valve 1 is switched from the "D" position to the "N" position shown in FIG. When the N shift is performed, the D range port is in drain communication. At this time, the drive signal of the solenoid valve 7 is turned off, and the solenoid pressure becomes full output, so that the control valve 6 is at the fully open position on the right side in the drawing, and the servo oil pressure of the hydraulic servo 2 is supplied to the supply oil passage Lc, the control valve 6, and the supply oil. The path Lb, the orifice 3, the supply oil path La, and the manual valve 1;
Under the influence of the hydraulic pressure released from the accumulator 5 to b, it is discharged while being throttled by the orifice 3 and gradually decreases, and finally enters the released state.

FIG. 2 is a time chart comparing the difference in control characteristics during the DN shift depending on the presence or absence of an accumulator. Middle figure shows the change in the servo hydraulic pressure Pc ₁ of the hydraulic servo 2 of the clutch C-1. In the case of the right column in the figure without the accumulator, the servo oil pressure Pc ₁ suddenly drops from the line pressure simultaneously with the DN shift, and then the residual pressure is discharged for a certain time due to the load of the return spring of the hydraulic servo 2. You can see that. When the servo oil pressure Pc ₁ suddenly drops, the transmission output shaft torque To shown in the upper part of the figure suddenly drops due to the release of the clutch, and overshoots to cause the torque oscillation, and eventually the torque becomes zero.
Converges to the state of. Incidentally, also the transmission input shaft rotational speed Nc ₁ shown in the lower figure increases with increasing slip of turbine speed eliminated of the torque converter in the released sudden load by the clutch release. This sudden change in torque is felt as a DN shift shock.

On the other hand, when there is an accumulator, the servo oil pressure Pc ₁ shown in the middle row of the right column of the figure starts decreasing at the same time as the DN shift, but the rate of the decrease becomes a gentle curve, and Similarly, the discharge of the residual pressure by the load of the return spring takes a certain time. Due to the gradual decrease in the servo oil pressure, the decrease in the transmission output shaft torque To shown in the upper right column of the figure is damped and becomes gentle, and the torque reaches zero without overshooting. In this case, the transmission input shaft rotation speed Nc ₁ shown in the lower right column of the figure also increases in accordance with the gradual increase in the turbine rotation speed accompanying the elimination of the slippage of the torque converter. This gradual torque change reduces the perceived DN shift shock.

When the clutch C-1 is engaged or disengaged to achieve a specific gear other than when starting, the circuit operation is such that the manual valve 1 is always in the "D" position and the orifice 3 is checked. Since the line pressure is always supplied to the supply oil passage La on the upstream side of the ball 4, the hydraulic pressure supply operation when the clutch C-1 is engaged is performed substantially in the same manner as in the ND shift. The effect of the accumulated pressure on the accumulator 5 is eliminated. The release of the servo hydraulic pressure from the hydraulic servo 2 when the clutch C-1 is released is exclusively performed by the drain control by the C1 solenoid valve according to the solenoid drive signal from the electronic control unit, and has nothing to do with the operation of the accumulator 5.

Thus, according to the circuit configuration of the first embodiment, when the hydraulic pressure is discharged from the hydraulic servo 2, the drive signal of the solenoid valve 7 is turned off, and the solenoid pressure becomes full output. The drain is controlled by the supply oil passage Lb on the more upstream side through the control valve 6 on the downstream side of the supply oil passage, so that the hydraulic pressure is slowly released using the accumulated pressure of the accumulator 2. Further, when the hydraulic pressure is supplied to the hydraulic servo 2, the communication of the supply oil path is controlled by the control valve 6 on the downstream side of the connection path of the accumulator 5 from the connection part of the accumulator 5. 2 is controlled. Therefore, according to this configuration, it is possible to achieve both reduction of the DN shift shock, improvement of the response at the time of the ND shift, and reduction of the shift shock. In addition, when the clutch C-1 is also used to achieve a specific shift speed, deterioration in shift shock can be prevented by improving controllability.

Incidentally, in the first embodiment, DN
The main purpose was to achieve both a gradual release of hydraulic pressure during the shift and an improvement in response during the ND shift and a reduction in shift shock. However, while focusing on this point, the hydraulic discharge of the clutch C-1 was replaced with a quick drain. A configuration that allows the user to make a selection is also possible in the spirit of the present invention. The necessity of such a quick drain arises, for example, when the viscosity of the hydraulic oil becomes high at a low temperature and the discharge of the servo hydraulic pressure is delayed.

Such a state can be dealt with in the above circuit configuration by changing the solenoid drive signal by the electronic control unit. In this case, the quick drain outputs the drive signal of the solenoid as a full output during the D-N shift,
This becomes possible by setting the solenoid pressure to zero. By this control, the control valve 6 shown in FIG. 1 becomes the drain communication position on the left side in the figure, and the servo hydraulic pressure of the hydraulic servo 2 becomes
The oil is rapidly drained from the supply oil passage Lc via the output port 6b of the control valve 6 and the drain port 6d.

FIG. 3 shows a circuit according to a second embodiment of the present invention.
The configuration is shown. As shown in the figure, this circuit
A bypass circuit a bypassing the valve 6 is provided.
Switching operation is performed by applying solenoid pressure to the bypass circuit
Supply oil passage Lc of the bypass circuit a _OneCommunication with the
Oil supply path Lc_OneAnd supply oil passage Lc_TwoDisconnection and communication between
A C1 apply relay valve 9 is used as a switching valve for switching.
Has been inserted. In this case, the control valve 6 of the supply oil passage
Downstream side of Lc_One, Lc_TwoIs a C1 apply relay valve
9 is connected to the hydraulic servo 2. With this change
Accordingly, the solenoid valve 7 is connected via the solenoid pressure oil passage L3.
To control valve 6 as signal pressure for pressure regulation.
Apply pressure and switch to C1 apply relay valve 9
Connection to apply solenoid pressure as signal pressure for
Have been.

The structure of the C1 apply relay valve 9 will be described in detail. This valve is a spring-return type switching valve having lands 91 and 92 at both ends and a spring 93 in contact with one of the lands 92. Land 9 on the load side
Blocking the short circuit due to the bypass circuit a across the control valve 6 1, to cut off the communication of the supply oil passage Lc ₁ and the supply oil passage Lc ₂ on the other land 92, the control valve 6 between the lands
And the supply oil passages Lc ₁ , Lc
_It is a valve that switches the communication between the _two . Therefore,
One input port 9a of this valve is connected to a bypass circuit a connected to the upstream side of the control valve 6, and the other input port 9b is connected to a supply oil passage Lc ₁ downstream of the control valve 6.
Is connected to the output port 9c is connected to the supply oil passage Lc _2. The pressure receiving portion on the land 91 end side is connected to the modulator pressure oil passage L2, and the pressure receiving portion on the spring load side land end is connected to the solenoid pressure oil passage L3.

In the circuit configuration of the second embodiment, when an ND shift is performed to switch the manual valve 1 from the illustrated "N" position to the "D" position, a line from the D range port to the supply oil passage La is provided. The pressure output is started, the check ball 4 is pushed open, and the hydraulic pressure is supplied from the supply oil passage Lb to the input port of the control valve 6. At this time, the control valve 6 in which the signal pressure output from the solenoid valve 7 in the state where the application of the drive signal to the linear solenoid 72 has been started from the electronic control device is applied to the spool end, the input port and the output port communicate. The C1 apply relay valve 9 in the fully opened state on the right side of the drawing and the modulator pressure applied to the spool end on the side opposite to the spring load side.
Since the input port 9a at the right side in the drawing is in a shut-off state, the hydraulic pressure via the control valve 6 is reduced by the oil passages Lc ₁ and Lc ₂
And is supplied to the hydraulic servo 2 rapidly. When the supply of the hydraulic pressure progresses and the pressure of the hydraulic servo 2 rises to near the line pressure, the pressing force applied to the spring load side spool end superimposed on the spring force exceeds the modulator pressure due to the increase in the solenoid pressure, The C1 apply relay valve 9 switches to the bypass communication state on the left side in the figure. After this switching, the hydraulic pressure is mainly supplied via the bypass circuit a. At this point, the accumulation of pressure in the accumulator 5 has already been completed and the engagement of the clutch C-1 has been completed. Does not matter. Therefore, also in the case of this circuit configuration, it is possible to quickly supply hydraulic pressure at the time of the ND shift, as in the first embodiment.

Next, when the hydraulic pressure is supplied to the hydraulic servo 2 and the clutch C-1 is engaged, DN
When the shift is performed, the D range port is in drain communication. At this time, when the solenoid pressure is continuously applied to the signal pressure port 6e of the control valve 6 by the solenoid valve 7, the control valve 6 maintains the communication state on the right side in the drawing,
Similarly, the C1 apply relay valve 9 maintains the communication state between the input port 9a and the output port 9c on the left side in the figure by applying the solenoid pressure on the spring load side. Accordingly, the servo oil pressure of the hydraulic servo 2 is reduced by the orifice 3 in the path of the supply oil passage Lc ₂ , the C1 apply relay valve 9, and the bypass circuit a while being affected by the exhaust pressure from the accumulator 5. , And slowly drain through the manual valve 1.

When the servo hydraulic pressure is discharged,
When the solenoid pressure is changed to the operation of draining by the solenoid valve 7 by changing the solenoid drive signal from the electronic control unit to the full output at the time of the DN shift, the control valve 6 is switched to the drain communication on the left side in the figure. At the same time, the C1 apply relay valve 9 also releases the application of the solenoid pressure on the spring load side and switches to the right position in the drawing, so that the servo hydraulic pressure of the hydraulic servo 2 is controlled by the supply oil passage Lc ₂ , the C1 apply relay valve 9, and the supply oil. Road L
c ₁ , drained rapidly in the path of the control valve 6. At this time, the exhaust pressure from the accumulator 5 is cut off by the C1 apply relay valve 9 and is not affected by the drain, but is drained by another route via the orifice 3, the supply oil passage La, and the manual valve 1. In this way,
By switching the signal output of the electronic control unit, a quick drain of the servo hydraulic pressure is also possible if necessary.

Thus, according to the circuit configuration of the second embodiment, the reduction of the DN shift shock by the same operation as that of the first embodiment, the improvement of the response during the ND shift, and the reduction of the shift shock are both achieved. Can be done. Also, in the case of this circuit configuration, quick drain of servo hydraulic pressure is also possible if necessary as described above.

As described above, the present invention has been described in detail with reference to the embodiments. However, the present invention is not limited to the illustrated embodiments, and can be variously modified within the scope of the claims.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a hydraulic control device according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a difference in a time change of a transmission output torque, a clutch servo hydraulic pressure, and a transmission input shaft rotation speed during an ND shift depending on the presence or absence of an accumulator.

FIG. 3 is a circuit diagram of a hydraulic control device according to a second embodiment of the present invention.

[Explanation of symbols]

C1 clutch 2 hydraulic servo 5 accumulator 6 Control valve 7 Solenoid valve 9 C1 apply relay valve (switching valve) La, Lb, Lc, Lc 1, Lc 2 supply oil path a bypass circuit

Continued on the front page (72) Inventor Masahiro Hayabuchi 10 Takane, Fujii-machi, Anjo, Aichi Prefecture Inside Aisin AW Co., Ltd. (72) Inventor Masaaki Nishida 10 Takane, Fujii-cho, Anjo, Aichi Aisin Ai F-term (reference) in W3 Co., Ltd. 3J552 MA01 MA12 NA01 NB01 PA03 PA20 QA02C QA06C QA13C QA33A QB02 RA21 SA03 VA63Z VA64Z VA65Z VA66Z VA67Z

Claims (5)

[Claims] 1. A hydraulic control device for an automatic transmission in which an accumulator is connected to a supply oil passage of a hydraulic servo for operating an engagement element, wherein a hydraulic servo is provided downstream from a connection of the accumulator on the supply oil passage. A hydraulic control device for an automatic transmission, wherein a control valve for controlling hydraulic pressure supply is interposed. 2. The hydraulic control device for an automatic transmission according to claim 1, wherein said control valve comprises a pressure regulating valve capable of controlling communication of a supply oil passage and a drain of a hydraulic servo. 3. A bypass circuit for bypassing a control valve to the supply oil passage, communication between the supply oil passage downstream of the control valve and disconnection of the bypass circuit, and disconnection of the supply oil passage and communication of the bypass circuit are switched. Provided with a switching valve,
The hydraulic control device for an automatic transmission according to claim 2. 4. The hydraulic control device for an automatic transmission according to claim 2, wherein a solenoid valve for applying a signal pressure to the control valve is provided to operate the control valve at a signal pressure. 5. The hydraulic control device for an automatic transmission according to claim 3, further comprising a solenoid valve for applying a signal pressure to the control valve and the switching valve so as to operate the control valve and the switching valve in a related manner.