JP2011185338A - Control device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve controllability during a lock-up condition without providing a delay means. <P>SOLUTION: When a lock-up clutch LC is engaged, an LC shift valve 5 is set to a lock-up ON position, and command hydraulic pressure (pilot pressure) according to an LC engagement command is applied from an LC controlling linear solenoid LS to an LC control valve 6. Accordingly, hydraulic fluid for engaging the clutch is supplied from the LC control valve 6 to the lock-up clutch LC through an oil passage 7, and hydraulic fluid pressure for engaging the lock-up clutch is increased. The hydraulic fluid pressure is supplied to a line pressure regulating valve 3 through the oil passage 9 and synchronized with a rise in hydraulic fluid pressure for engaging the lock-up clutch, thereby reducing the line pressure. Therefore, by reducing the line pressure by being synchronized with the engagement of the lock-up clutch of a torque converter, a load on an oil pump is efficiently reduced. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an automatic transmission control device including a torque converter lockup mechanism.

  In general, the line pressure of an automatic transmission is set high considering the torque ratio of the torque converter. However, in the lock-up state, the torque converter does not increase the torque, so the line pressure becomes higher than necessary, increasing the load on the oil pump and deteriorating the fuel consumption rate. Become. In view of this point, in Patent Document 1 below, by reducing the line pressure in the lock-up state of the torque converter, the load of the oil pump is reduced and the deterioration of the fuel consumption rate is prevented. As a control method, the lockup command pressure given from the lockup solenoid to the lockup control valve is branched and given to the line pressure regulating valve, and the line pressure is controlled to be lowered when the lockup command pressure is given. . In this case, as the lockup command pressure increases, the lockup clutch pressure operated by the lockup control valve increases, the lockup clutch is engaged, and the line pressure decreases accordingly. Become. However, if the line pressure drops faster than the lockup clutch pressure rises, the torque converter slips on the frictional engagement element due to the line pressure drop, despite the torque-amplified rotation still being given to the transmission. This causes the inconvenience that it will appear. In order to prevent such inconvenience, Patent Document 1 provides a delay means including a one-way orifice and an accumulator in an oil passage for applying a lockup command pressure to the line pressure regulating valve. By providing such a delay means, an increase in the lockup command pressure is transmitted to the line pressure regulating valve with a delay, and the line pressure can be lowered after the lockup clutch pressure has been reliably increased. .

Japanese Patent No. 3104518

  In the control method as described in Patent Document 1, since it is necessary to provide delay means in the oil passage for applying the lockup command pressure to the line pressure regulating valve, it is solved that the number of parts is increased and the cost is increased. There are issues to be solved. In addition, since there is always a delay between the increase of the lockup clutch pressure and the decrease of the line pressure, there is a problem to be solved in terms of controllability.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a control device for an automatic transmission that can improve the controllability at the time of lockup without providing a delay means.

  The control device for an automatic transmission according to the present invention controls an oil pump (2) that discharges oil pressure to a line pressure oil passage (1), and controls the oil pressure of the line pressure oil passage by regulating the discharge pressure of the oil pump. Line pressure control means (3) for controlling, lockup command means (LS, 5, 8) for generating command signals for controlling engagement and disengagement of the lockup clutch (LC) of the torque converter, and the lockup clutch A lockup clutch control means (6) for supplying hydraulic oil for fastening the lockup clutch to the lockup clutch in response to the command signal for instructing the engagement of the lockup clutch, and the lockup clutch control means from the lockup clutch control means. The hydraulic oil for fastening the lockup clutch supplied to the clutch is used as the command pressure for reducing the line pressure. Comprising oil passage supplied to the pressure control means (9). Note that the reference numbers in parentheses indicate the reference numbers of each element in the embodiment described later corresponding to each component of the present invention for reference only.

  According to the present invention, the hydraulic oil for fastening the lockup clutch supplied from the lockup clutch control means to the lockup clutch is supplied to the line pressure control means as a command pressure for reducing the line pressure. Since the road is configured, the command pressure for reducing the line pressure to the line pressure control means can be synchronized with the hydraulic pressure for engaging the lockup clutch. Therefore, since the increase of the lockup clutch pressure and the decrease of the line pressure are always synchronized, the line pressure does not decrease before the increase of the lockup clutch pressure, and the controllability at the time of lockup can be improved. it can. Further, special delay means for preventing the line pressure from decreasing before the lockup clutch pressure increases is unnecessary.

The figure which shows the outline of the hydraulic system of the control apparatus of the automatic transmission which concerns on one Embodiment of this invention. The figure which lists and shows an example of the operating states of each apparatus etc. which are shown in FIG. 1 according to a vehicle running state.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows a hydraulic system for line pressure control and torque converter lock-up clutch control according to an embodiment of the present invention. The hydraulic system for line pressure control includes an oil pump 2 that discharges oil pressure to the line pressure oil passage 1, and a line pressure pressure regulator that regulates the discharge pressure of the oil pump 2 to control the oil pressure of the line pressure oil passage 1. And a valve 3 (line pressure control means).

  In the hydraulic system 4 for lockup clutch control, the LC control linear solenoid LS generates a command signal (pilot pressure) for controlling the engagement and release of the lockup clutch LC of the torque converter (lockup command means). . A command signal (pilot pressure) from the LC control linear solenoid LS is given to the LC control valve 6 via the LC shift valve 5. The LC control valve 6 is activated in response to a command signal (pilot pressure) from the LC control linear solenoid LS, and the hydraulic oil for fastening the lockup clutch LC is supplied via the oil passage 7 to the lockup clutch LC. (Lock-up clutch control means). On the other hand, in a state where the command signal (pilot pressure) from the LC control linear solenoid LS is not supplied, the LC control valve 6 is inoperative and no hydraulic oil is supplied to the oil passage 7. The LC shift valve 5 (switching valve) is switched to one of a lockup ON position (operating state) and an OFF position (non-operating state) by an LC on / off switching solenoid 8. When the LC shift valve 5 is set to the lock-up ON position (operating state), a command signal (pilot pressure) from the LC control linear solenoid LS is given to the LC control valve 6.

  Supply hydraulic oil for fastening the lockup clutch LC supplied from the LC control valve 6 to the lockup clutch LC via the oil passage 7 to the line pressure regulating valve 3 as a command pressure for reducing the line pressure. In order to do so, an oil passage 9 is formed. The oil pressure in the oil passage 7 is also returned to the LC control valve 6 through the oil passage 10. Thus, the oil for supplying the lockup clutch fastening oil supplied from the LC control valve 6 to the lockup clutch LC is supplied to the line pressure regulating valve 3 as a command pressure for lowering the line pressure. Since the path 9 is configured, the command pressure for reducing the line pressure with respect to the line pressure regulating valve 3 can be synchronized with the hydraulic pressure for engaging the lockup clutch. Therefore, the increase in the lockup clutch pressure and the decrease in the line pressure are always synchronized.

  Next, the operation example of FIG. 1 will be described with reference to FIG. FIG. 2 shows the operating state of each device corresponding to three types of vehicle driving states of “steady driving”, “rapid acceleration”, and “stall”, and lock-up realized according to the operating state of each device. The state of the clutch LC and the state of the line pressure are shown.

  As shown in the column of “steady running” in FIG. 2, when the lockup clutch LC is turned on during steady running, an LC on command is sent from an electronic control device (not shown) to the LC on / off switching solenoid 8. (ON) is given, and an LC fastening command is given to the LC control linear solenoid LS. As a result, the LC shift valve 5 is set to the lock-up ON position (operating state), and the LC control linear solenoid LS is in a state (ON) where the command hydraulic pressure (pilot pressure) corresponding to the LC engagement command is generated. The command hydraulic pressure (pilot pressure) generated from the LC control linear solenoid LS is applied to the LC control valve 6. In response to this, the LC control valve 6 is activated, hydraulic oil for clutch engagement is supplied from the LC control valve 6 to the lockup clutch LC via the oil passage 7, and the hydraulic pressure for engagement of the lockup clutch is reduced. To rise. As a result, the lockup clutch LC is engaged (ON). This hydraulic pressure is supplied to the line pressure regulating valve 3 via the oil passage 9, and the line pressure is lowered (low pressure) in synchronization with the increase of the hydraulic pressure for engaging the lockup clutch. Therefore, the load of the oil pump can be reduced efficiently by reducing the line pressure in synchronization with the lockup clutch engagement of the torque converter.

  As shown in the column of “rapid acceleration” or “stall” in FIG. 2, when releasing the lockup, an LC off command (OFF) is sent from the electronic control unit (not shown) to the LC on / off switching solenoid 8. ) And an off command (OFF) is given to the LC control linear solenoid LS. As a result, the LC shift valve 5 is set to the lock-up OFF position (non-operating state), and the LC control linear solenoid LS is in a state (OFF) in which the command hydraulic pressure (pilot pressure) is not generated. In response to this, the command signal (pilot pressure) for the LC control valve 6 disappears, the LC control valve 6 becomes inoperative, the oil pressure of the oil passage 7 decreases, and the lockup is released (OFF). Further, since the command pressure from the oil passage 9 to the line pressure regulating valve 3 also disappears, the line pressure increases (high pressure).

  The command signal (pilot pressure) for the LC control valve 6 is generated via a duplicated control system including the LC control linear solenoid LS, the LC shift valve 5 and the LC on / off switching solenoid 8. The reason is because of the fail-safe function. For example, even if an unnecessary lockup command signal (pilot pressure) is erroneously generated due to a failure of the LC control linear solenoid LS, the LC shift valve 5 is operated by the normally operating LC on / off switching solenoid 8. Since the lock-up OFF position is set, the LC control valve 6 does not malfunction and is safe.

1 Line pressure oil passage 2 Oil pump 3 Line pressure regulating valve (Line pressure control means)
LS LC control linear solenoid 5 LC shift valve 8 LC on / off switching solenoid LC Lock-up clutch 9 Oil path for line pressure control

Claims (2)

An oil pump that discharges hydraulic pressure to the line pressure oil path;
A line pressure control means for controlling the oil pressure of the line pressure oil passage by regulating the discharge pressure of the oil pump;
Lockup command means for generating a command signal for controlling engagement and disengagement of the lockup clutch of the torque converter;
Lock-up clutch control means for supplying hydraulic oil for fastening the lock-up clutch to the lock-up clutch in response to the command signal that commands the fastening of the lock-up clutch;
An oil passage for supplying hydraulic oil for fastening the lockup clutch supplied to the lockup clutch from the lockup clutch control means to the line pressure control means as a command pressure for reducing the line pressure; A control device for an automatic transmission comprising:   2. The automatic transmission according to claim 1, wherein the lockup clutch control means includes a control valve that supplies hydraulic pressure for clutch engagement and a switching valve that turns on / off the supply of hydraulic oil to the lockup clutch. Control device.

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