JPS6044643A - Hydraulic control method of automatic speed change gear for car - Google Patents

Abstract

PURPOSE:To improve economization of fuel and to prevent generation of a speed change shock by properly setting line oil pressure according to a selected shift pattern. CONSTITUTION:A drain open-and-close valve 18 is connected to a pilot port 15 of a line oil pressure control valve 4, and in a power mode, an electric switch 24 is closed to close the drain open-and-close valve 18 to increase the upward force worked upon a spool 6 and enlarge a counter balance value of a spool 5, resulting in increasing the line oil pressure for the same stepping amount of an acceleration pedal as compared with an economy mode. Thus, line oil pressure can be set at a proper line oil pressure according to a selected shift pattern, which can avoid a loss of an auxiliary machinery by an oil pump. Accordinly, the economization of an engine fuel can be improved and the generation of a speed change shock can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hydraulic control method for an automatic transmission used in vehicles such as automobiles, and particularly relates to a hydraulic control method for an automatic transmission used in a vehicle such as an automobile. The present invention relates to a hydraulic control method for a vehicle automatic transmission that changes gears according to a shift pattern.

BACKGROUND OF THE INVENTION, PRIOR TECHNOLOGIES, AND PROBLEMS Automatic transmissions for vehicles automatically shift gears according to a predetermined shift pattern depending on the depression of the accelerator pedal and the vehicle speed. is performed by a microcomputer, the first shift pattern is generally called economy mode, in which the gear is shifted at a relatively low vehicle speed compared to the amount of depression of the accelerator pedal, and the amount of depression of the accelerator pedal is In comparison, the gears are shifted at a relatively high medium speed and a second shift pattern is generally referred to as power mode.Which of these two shift patterns is selected by the driver is one shift pattern. An automatic transmission for a vehicle is known that is configured to change gears according to the following.

Shifting of an automatic transmission for a vehicle is performed by engaging or disengaging a frictional engagement device such as a clutch or a brake, and in many cases, the frictional engagement device is driven by a hydraulic actuator to engage or disengage the frictional engagement device. It's meant to be liberating. Hydraulic pressure is supplied and discharged to and from the hydraulic actuator by a hydraulic control device equipped with various hydraulic control valves and hydraulic switching valves. It has a line oil pressure control valve, generally called a primary regulator valve, that regulates the oil pressure to increase in accordance with an increase in the oil pressure. The hydraulic power is selectively supplied to the hydraulic actuator via a speed change valve that is switched depending on the vehicle speed.

As mentioned above, the oil pressure supplied to the hydraulic actuator is controlled by the line oil pressure control valve to the oil pressure (line oil pressure) that matches the amount of depression of the accelerator pedal, that is, the engine output, thereby reducing engine auxiliary equipment loss due to the oil pump. However, conventionally, line oil pressure generally changes with only one characteristic depending on the amount of accelerator pedal depression, except when in reverse, and the line oil pressure at a certain amount of accelerator pedal depression is always constant except when in reverse. be.

As mentioned above, when shifting is performed according to one of the first shift pattern and the second shift pattern, the second shift pattern is more effective than the first shift pattern. In this case, since the vehicle speed at the shift point is higher, a larger driving force is required to engage the frictional engagement device, and therefore, the appropriate line oil pressure required for engagement of the frictional engagement device is determined by the first shift pattern. It is higher in the case of using the second hydraulic actuator than in the case of using the second hydraulic actuator.

In conventional hydraulic control devices, the line hydraulic pressure is always constant at a given accelerator pedal depression amount as described above, so when a shift pattern is selected and set,
The line oil pressure is set to the appropriate line oil pressure for the second shift pattern. When the line oil pressure is set in this way, when shifting is performed according to the first shift pattern, the line oil pressure will be higher than the appropriate line oil pressure for this shift pattern, and this will inevitably cause the line oil pressure to be higher than necessary. line hydraulic pressure, resulting in unnecessary loss of auxiliary equipment due to the oil pump.
Engine fuel economy deteriorates.

Also, if the line oil pressure is higher than the appropriate line oil pressure, the shift shock will be large.

Purpose of the Invention The present invention is capable of setting the line oil pressure to an appropriate line oil pressure according to the selected shift pattern, thereby avoiding wasteful loss of auxiliary equipment caused by the oil pump, and improving the fuel economy of the engine. It is an object of the present invention to provide a hydraulic control method for an automatic transmission for a vehicle, which can improve the speed change and which does not cause a large shift shock.

According to the present invention, it is an object of the present invention to provide hydraulic control of an automatic transmission for a vehicle in which a shift is performed according to one of the first shift pattern and the second shift pattern as described above. In this method, the hydraulic pressure supplied to a hydraulic actuator that drives a frictional engagement device that switches gears is increased in accordance with an increase in accelerator pedal depression, and the value is increased to the same accelerator pedal depression amount. On the other hand, when the shift is performed using the second shift pattern, this is achieved by a hydraulic control method that increases the hydraulic pressure compared to when the shift is performed using the first shift pattern.

DESCRIPTION OF EMBODIMENTS The present invention will now be described in detail with reference to embodiments with reference to the accompanying drawings.

FIG. 1 shows the main parts of one embodiment of a hydraulic control device for carrying out the hydraulic control method for a vehicle automatic transmission according to the present invention. In the figure, reference numeral 1 indicates an oil pump, which is driven by an engine (not shown), sucks up oil stored in an oil reservoir 2 such as an oil pan, and sends the oil through an oil passage 3. The water is then supplied to a speed change valve (not shown). A line oil pressure control valve 4 is connected in the middle of the oil passage 3.

The line oil pressure control valve 4 includes two spools 5 and 6 that are movably provided in the valve bore in the vertical direction as shown in the figure, an inlet boat 7 connected to the middle of the oil passage 3, and an outlet boat connected to a drain. 8, outlet ports 9 and 10 connected to a converter hydraulic control valve (secondary regulator valve) not shown in the figure, and an oil passage 3 via a throttle 11.
Throttle hydraulic pressure is supplied from a pilot boat 1-2 connected midway through the throttle valve 1-2 and a throttle oil pressure control valve (not shown) that increases according to the throttle opening, that is, the amount of accelerator pedal depression. Throttle boat 13 and
A reverse boat 14 to which line hydraulic pressure is supplied only during reverse, a mode boat 15 to which line hydraulic pressure is selectively supplied according to the selected shift pattern, and a compression coil spring that biases the spool 5 upward as shown in the figure. 16.

The spool 5 is driven based on a balanced relationship between a downward force in the figure given by the hydraulic pressure introduced into the pilot boat 12 and an upward force in the figure exerted by the compression coil spring 16 and the spool 6. When the downward force in the figure is larger than the upward force in the figure, the degree of communication between the inlet port 7 and the outlet boat 8 and the degree of communication between the inlet boat 7 and the outlet boat 1° are respectively increased; When the upward force in the figure is greater than the downward force in the figure, the two degrees of communication are respectively reduced.

As the spool 5 operates as described above, the oil pressure in the oil passage 3 increases as the throttle opening increases, and this oil pressure is called line oil pressure.

When line hydraulic pressure is supplied to the pilot boat 14 or when line hydraulic pressure is supplied to the mode boat 15, the line hydraulic pressure acts on the spool 6 as an upward force as shown in the figure. By increasing the upward force at , the equilibrium value of the spool 5 increases,
The line oil pressure becomes higher for the same amount of accelerator pedal depression than when no line oil pressure is supplied to the pilot boats 14 and 15.

The pilot boat 15 is equipped with a hydraulic till I according to the invention.
This is a newly installed boat for carrying out Method II, and the pilot boat is connected to the middle of the oil passage 3 via the oil passage 17, and has an electromagnetically actuated drain opening/closing valve connected to the middle of the oil passage 17. drain boat 19 by 18
Line hydraulic pressure is supplied only when the is closed.

The drain opening/closing valve 18 separates the drain boat 19 by separating the valve element 22 from the drain port 19 by the spring force of the spring 21 when the solenoid 20 is not energized, whereas the solenoid 20 is energized. When this occurs, the valve element 22 resists the spring force of the spring 21 due to the magnetic attraction force of the solenoid, and the drain boat 1
9 and close the drain boat.

Current is selectively supplied to the solenoid 20 from a battery power supply 23 via an electric switch 24. The electric switch 24 is turned on and off in response to a shift pattern selection operation performed by the driver, and the selected shift pattern is a first shift pattern that changes gears at a relatively low vehicle speed compared to the amount of depression of the accelerator pedal. It opens when the shift pattern is in economy mode, whereas when the selected shift pattern is a second shift pattern that changes gears at a relatively high vehicle speed compared to the amount of depression of the accelerator pedal, in other words power mode. It is supposed to close.

Effects of the Invention As described above, when the shift pattern is set to the second shift pattern, that is, in the power mode, the electric switch 24 closes and the drain opening/closing valve closes.

18 is closed, the drain boat 19 is closed, and line hydraulic pressure is supplied to the pilot boat 15, so that the upward force acting on the spool 6 increases in the figure, and the equilibrium value of the spool 5 increases accordingly. However, the line oil pressure increases for the same accelerator pedal depression compared to when the first shift pattern is used, that is, when the economy mode is used.

FIG. 2 shows the relationship between the throttle rI0 degrees and the line oil pressure. In FIG. 2, the solid line shows the line oil pressure in the economy mode, and the dashed line shows the line oil pressure in the power mode. As is clear from the graph shown in FIG. 2, according to the hydraulic pressure control method according to the present invention, the line hydraulic pressure is set to different appropriate line hydraulic pressures in the economy mode and the power mode. The speed change control of automatic transmissions for vehicles is performed accurately without increasing unnecessary friction loss of the engine due to the pump, the durability and reliability of the friction material of the friction engagement device is improved, and large speed change shocks are prevented. do not have.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto.
It will be apparent to those skilled in the art that various embodiments are possible within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing the main parts of an embodiment of a hydraulic control device for carrying out the hydraulic control method for an automatic transmission for vehicles according to the present invention, and FIG. It is a graph showing line hydraulic characteristics in economy mode and power mode. 1...Oil pump, 2...Oil pan, 3...
Oil passage, 4... line hydraulic control valve, 5.6... spool. 7... Inlet port, 8-10... Outlet boat, 11
... Aperture, 12-15 ... Pilot boat, 16
...Compression coil spring, 17...Oil passage, 18...
Drain on/off valve, 19...Drain boat, 20...
·solenoid. 21... Spring, 22... Valve element, 22... Battery power source. 24... Electrical switch patent applicant Toyota Motor Corporation Representative Patent attorney Masaki Akashi

Claims (1)

[Claims] The shift pattern is selected from a first shift pattern in which the gear is shifted at a relatively low vehicle speed compared to the amount of depression of the accelerator pedal, and a second shift pattern in which the gear is shifted at a relatively high vehicle speed compared to the amount of depression of the accelerator pedal. In a hydraulic control method for a vehicle automatic transmission in which gears are changed according to one of the shift patterns, the hydraulic pressure supplied to a hydraulic actuator that drives a friction engagement device that changes gears is controlled by pressing an accelerator pedal. When the gear shift is performed using the second shift pattern for the same amount of depression of the accelerator pedal, the value increases in accordance with the increase in the amount, and when the gear shift is performed using the second shift pattern, compared to when the gear shift is performed using the first shift pattern. A hydraulic control method characterized by a high pressure.