JP2015081611A - Hydraulic control device of automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control device of an automatic transmission which prevents a delay of the drain of engagement pressure more than necessary, and can avoid a problem of the drag of a clutch while avoiding a cost increase resulting from the addition of an exclusive bypass valve.SOLUTION: When an automatic gear change device is switched to an N-range from a D-range in a state that an oil temperature or an atmospheric temperature is equal to or lower than a prescribed temperature, or a first solenoid valve 6 is locked to an open position, engagement pressure PC to a forward clutch C2 is directly drained via a limp home shift valve 9 and a manual shift valve 4 not via the first solenoid valve 6 and an orifice 8 by switching the limp home shift valve 9 to a drain position by signal pressure PS2 from a second solenoid valve 10.

Description

The present invention relates to a hydraulic control device for an automatic transmission, and more specifically, the drain of the engagement pressure to the friction engagement element at an extremely low temperature or an open lock failure of the first solenoid valve for supplying the engagement pressure is more than necessary. The present invention relates to a hydraulic control device capable of avoiding dragging of a friction engagement element due to delay.

A hydraulic control device for an automatic transmission for an automobile may employ a hydraulic circuit that directly controls each clutch / brake hydraulic pressure with a solenoid valve for the purpose of improving the hydraulic response at the time of shifting. However, when such a hydraulic circuit is adopted, there is a possibility that the vehicle cannot run when the solenoid valve for controlling the hydraulic pressure to the forward clutch fastened on the low side of the forward range is closed. Therefore, conventionally, a limp home shift valve is provided, and in the event of a failure, the hydraulic pressure to the forward clutch is controlled by the limp home shift valve to avoid the problem of inability to travel.

In the hydraulic control device, when the D range is switched to the N range, the engagement pressure supplied to the forward clutch (forward friction engagement element) is drained through the orifice, so that the forward clutch suddenly There are cases in which shocks due to openness are prevented.

  On the other hand, when draining through the orifice, the viscosity of the oil increases at an extremely low temperature, and the drain of the engagement pressure is delayed more than necessary, causing the clutch to drag and the vehicle to There is a problem of not behaving.

Therefore, a passage that bypasses the orifice is provided, and a bypass valve that opens and closes the bypass passage is provided. When the temperature of the hydraulic oil is equal to or lower than a predetermined value, the bypass valve is opened so that the drain of the engagement pressure is more than necessary. There has been proposed one that prevents delay and eliminates the problem of clutch dragging (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 4-254059

In the case of the conventional apparatus described in the above-mentioned patent document, there is a problem that a dedicated bypass passage for bypassing the orifice is provided, and a dedicated bypass valve is disposed in the bypass passage, which increases the cost accordingly.

  The present invention has been made in view of the above-described conventional situation, and prevents the drainage of the engagement pressure from being delayed more than necessary while avoiding the high cost due to the addition of a dedicated bypass valve. It is an object of the present invention to provide a hydraulic control device for an automatic transmission that can avoid the drag problem.

The present invention adjusts the range pressure supplied from the manual shift valve via the valve to the engagement pressure by the first solenoid valve and supplies the friction pressure to the friction engagement element via the limp home shift valve during forward travel of the D range. The friction engagement element is fastened, and when switching to the N range, the engagement pressure to the friction engagement element is changed to the limp home shift valve, the first solenoid valve, an orifice bypassing the valve, and In the hydraulic control device for an automatic transmission that opens the friction engagement element by draining through the manual shift valve,
When the oil temperature or the atmospheric temperature is lower than the predetermined temperature or when the first solenoid valve is locked at the open position and the D range is switched to the N range, the limp home shift valve is driven by the signal pressure from the second solenoid valve. By switching to a drain position, the engagement pressure is directly drained through the limp home shift valve and the manual shift valve without passing through the first solenoid valve and the orifice.

According to the present invention, when the first solenoid valve is switched from the D range to the N range in an abnormal state where the temperature is equal to or lower than the predetermined temperature or the first solenoid valve is locked at the open position, Since the shift valve is switched to the drain position, the engagement pressure can be directly drained through the limp home shift valve and the manual shift valve without passing through the first solenoid valve and the orifice. It is possible to prevent the clutch from being dragged due to a delay in the combined pressure drain, and to prevent the vehicle from unintentionally operating by the driver during the N-range shift.

  Further, in the present invention, when the first solenoid valve is in the open lock state, the above-described limp home which is conventionally provided to supply a predetermined pressure to the friction engagement element without passing through the first solenoid valve. Since the engagement pressure is drained directly from the manual shift valve by using the shift valve, there is no need to provide a dedicated bypass passage and bypass valve for bypassing the orifice. Cost increase can be avoided.

It is a hydraulic circuit diagram at the time of D range driving | running | working in the normal state in the hydraulic control apparatus of the automatic transmission which concerns on Example 1 of this invention. It is a hydraulic circuit diagram at the time of switching from the D range to the N range in the normal state of the hydraulic control device. It is a hydraulic circuit diagram at the time of switching from the D range to the N range in the abnormal state of the hydraulic control device. It is a block block diagram of the hydraulic circuit of the said hydraulic control apparatus.

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

1 to 3 are views for explaining a hydraulic control device for an automatic transmission according to a first embodiment of the present invention.

In the figure, reference numeral 1 denotes a hydraulic control device for an automobile automatic transmission according to the first embodiment. In this embodiment, the description of the hydraulic circuit portion that is not directly related to the present invention is omitted.

The hydraulic control apparatus 1 of the present embodiment sucks oil from an oil pan (not shown) through an oil strainer 2a, and inputs an oil pump 2 that pressurizes and discharges the discharge pressure of the oil pump 2. (Primary pressure) A primary regulator 3 that regulates and outputs PL, and a line pressure PL from the regulator 3 is input through the hydraulic passage 11a, and a manual that outputs a range pressure PD corresponding to the shift position, for example, the D range. The range pressure PD from the shift valve 4 and the manual shift valve 4 is input through the hydraulic passage 11b, and the range pressure PD is adjusted to the engagement pressure PC corresponding to the operating state to adjust the forward clutch (friction engagement element). ) A first solenoid valve (C2Sol) 6 for supplying to C2.

Further, in the hydraulic pressure control device 1, the range pressure PD from the manual shift valve 4 is directly passed to the first solenoid valve 6 side in the hydraulic passage 11 b connecting the manual shift valve 4 and the first solenoid valve 6. A one-way valve 7 is provided, and an orifice 8 is provided in the bypass passage 8a of the one-way valve 7 to avoid sudden opening of the forward clutch C2 by draining the engagement pressure PC at a relatively low speed. Is installed.

Furthermore, in the hydraulic passage 11c that connects the first solenoid valve 6 and the forward clutch C2, when the first solenoid valve 6 is open-locked, a predetermined pressure PC ′ is passed through the hydraulic passages 11b, 11d, and 11c. A limp home shift valve 9 for supplying to the forward clutch C2 is interposed. The limp home shift valve 9 is connected to a second solenoid valve 10 for supplying the first signal pressure PS1 at the normal time or the second signal pressure PS2 at the time of the abnormality by a signal line 10a.

When the oil temperature or the ambient temperature exceeds the predetermined temperature and the first solenoid valve 6 is operating normally, in the forward traveling state in which the shift lever (not shown) is positioned in the D range, The spool 4a of the shift valve 4 is located at the position shown in the upper half of FIG. 1, and the line pressure PL supplied to the port 4b serves as the range pressure PD from the port 4c via the one-way valve 7 and the first solenoid. Supplied to the valve 6. The same applies when the shift lever is located in the 2 range and the L range.

The first solenoid valve 6 regulates the range pressure PD to an engagement pressure PC corresponding to an operation state such as an accelerator pedal depression amount and a vehicle speed, and the engagement pressure PC is supplied to the limp home shift valve 9. . At this time, the spool 9a of the limp home shift valve 9 is in the right end position shown in the upper half of FIG. 1 because the normal first signal pressure PS1 is supplied from the second solenoid valve 10. The engagement pressure PC is supplied from the port 9b to the forward clutch C2 through the port 9c. As a result, the forward clutch C is engaged, and the vehicle moves forward normally.

Further, when the first solenoid valve 6 is in an open lock fail state in which the first solenoid valve 6 is locked at the open position, the second signal pressure PS2 at the time of abnormality is supplied to the limp home solenoid valve 9 from the second solenoid valve 10. The spool 9a is moved to the position shown in the lower half of FIG. 1, so that the range pressure PD from the manual shift valve 4 is transferred from the hydraulic passages 11b and 11d to the forward clutch C2 through the ports 9d and 9c. As a result, the clutch C2 is engaged, and the vehicle can barely move forward.

When the shift lever is switched to the N range in the normal state, the spool 4a of the manual shift valve 4 moves to the position shown in the lower half of FIG. 2, the port 4c is closed, and the port 4d is opened. This allows draining. The spool 9a of the limp home shift valve 9 is in a position where the right ports 9c and 9b shown in the upper half of FIG. Therefore, the engagement pressure PC supplied to the forward clutch C2 passes through the ports 9c and 9b of the limp home shift valve 9, passes through the orifice 8 from the first solenoid valve 6, and passes through the orifice 8 of the manual shift valve 4. Drained from port 4d.

Furthermore, when the shift lever is shifted from the D range to the N range in an abnormal state where the oil temperature or the atmospheric temperature is equal to or lower than the predetermined temperature or the first solenoid valve 6 is in the open lock fail state, the manual shift is performed. The spool 4a of the valve 4 moves to the position shown in the lower half of FIG. 3, the port 4c is closed, and the port 4d is opened, so that the drain is ready.

On the other hand, the limp home shift valve 9 is supplied with the second signal pressure PS2 in the abnormal state from the second solenoid valve 10, and the spool 9a moves to the position shown in the lower half of FIG. Then, the port 9b is closed and the ports 9c and 9d are connected. As a result, the engagement pressure PC supplied to the forward clutch C2 passes from the hydraulic passage 11c through the ports 9c and 9d and the hydraulic passage 11d, and through the hydraulic passage 11a without passing through the first solenoid valve 6 and the orifice 8. Then, the fluid is drained from the port 4d of the manual shift valve 4.

As described above, in the first embodiment, when the oil temperature or the ambient temperature is lower than the predetermined temperature or when the first solenoid valve 6 is locked in the open position, the second solenoid valve is switched from the D range to the N range. Since the limp home shift valve 9 is switched to the drain position by the second signal pressure PS2 at the time of abnormality from 10, the engagement pressure PC does not go through the first solenoid valve 6 and the orifice 8 and the limp home. The shift valve 9 can be directly drained from the port 4d of the manual shift valve 4 through the hydraulic passages 11d and 11a.

As a result, the engagement pressure PC can be drained immediately, dragging of the forward clutch C2 due to drain delay can be prevented, and the vehicle does not behave unintentionally by the driver during N-range shift.

  In the first embodiment, when the first solenoid valve 6 is in an open lock state, the constant pressure PC ′ is provided to the forward clutch C2 as soon as possible without going through the first solenoid valve 6. Since the engagement pressure PC is directly drained from the manual shift valve 4 by using the limp home shift valve 9, there is no need to provide a dedicated bypass passage and bypass valve for bypassing the orifice. It is possible to avoid an increase in cost for securing pressure drain.

  In the first embodiment, the one-way valve 7 is provided between the manual shift valve 4 and the first solenoid valve 6, but an electromagnetic opening / closing valve is provided instead of the one-way valve 7, and the electromagnetic opening / closing valve is installed when traveling in the D range. The electromagnetic on-off valve may be closed when opening and switching from the D range to the N range.

4 Manual shift valve 6 First solenoid valve 7 One-way valve (valve)
8 Orifice 9 Limp home shift valve 10 Second solenoid valve C2 Forward clutch (friction engagement element)
PD range pressure
PC engagement pressure
PS1 1st signal pressure
PS2 Second signal pressure

Claims (1)

During forward running of the D range, the range pressure supplied from the manual shift valve via the valve is adjusted to the engagement pressure by the first solenoid valve, and then supplied to the friction engagement element via the limp home shift valve. At the time of switching to the N range by fastening the friction engagement element, the pressure applied to the friction engagement element is changed to the limp home shift valve, the first solenoid valve, the orifice bypassing the valve, and the manual shift valve. In the hydraulic control device for an automatic transmission, wherein the friction engagement element is released by draining through
When the oil temperature or the atmospheric temperature is lower than the predetermined temperature or when the first solenoid valve is locked at the open position and the D range is switched to the N range, the limp home shift valve is driven by the signal pressure from the second solenoid valve. The hydraulic pressure of the automatic transmission is characterized in that the engagement pressure is directly drained through the limp home shift valve and the manual shift valve without passing through the first solenoid valve and the orifice by switching to the drain position. Control device.

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