JP2000199562A - Hydraulic control method and hydraulic control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control method and device for an automatic transmission capable of performing rapid and smooth shifting at any step when selected from a neutral range to a drive range. SOLUTION: This hydraulic control device for an automatic transmission comprises at least a throttle opening sensor 3; a car speed sensor 4 for detecting a car speed; a shift position switch 5 for detecting a shift position; a hydraulic control means 6 inputted with signals S3, S4, and S5 from respective sensors; and a line pressure solenoid 14 inputted with a signal from the hydraulic control means 6. By providing the hydraulic control means 6 with a line pressure control part for changing a line pressure according to the number of steps when a signal from the shift position switch 5 is switched from a neutral range to a drive range, a line pressure can be set according to the constituting step, whereby lengthening of an engaging time of a friction element and a shock due to engagement of the friction element are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control method and a hydraulic control apparatus for an automatic transmission, and more particularly, to a line pressure at the time of shifting of an automatic transmission when a shift position is switched from a neutral range to a drive range. The present invention relates to a hydraulic control method and a hydraulic control device for an automatic transmission, which controls the control by changing the speed according to the number of gears.

[0002]

2. Description of the Related Art Conventionally, as a hydraulic control device for an automatic transmission, for example, as disclosed in JP-A-3-28571, a drive that travels forward from a neutral range (N) in which a friction element is not fastened is disclosed. When the line pressure supplied to the friction element is temporarily increased suddenly when the range (D) is switched, the precharge pressure is generated by rapidly decreasing the line pressure, and the line pressure is gradually increased from the time when the precharge pressure decreases. I have. Thus, the preparation for engaging the friction element is performed with the precharge pressure, and the line pressure is gradually increased, thereby reducing the shift shock at the time of engaging the friction element.

[0003]

However, in the hydraulic control device for an automatic transmission disclosed in Japanese Patent Application Laid-Open No. 3-28571, a normal start gear (normal speed) is selected.
No consideration is given to the case where a gear other than (1st gear) is configured. For this reason, for example, when the speed is changed directly from neutral to a speed other than the first speed by selecting from N to D during traveling, it is impossible to configure the first speed due to a failure of the shift solenoid that switches the friction element between on and off. In the case of, when the shift speed is fixed to the high speed stage by the fail-safe operation at the time of failure of the vehicle speed sensor for detecting the vehicle speed, the friction element to be engaged by selecting N → D is 1
No more steps. Therefore, even if the line pressure is optimal when one stage is configured by selecting N → D, the N → D
The selection is not always optimal when the shift speed is changed to a speed other than the first speed, and it may be considered that the engagement takes time or the engagement shock increases.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems, and when neutral (N) → drive (D) is selected, smooth shifting can be performed in a short time regardless of the number of gears. It is an object of the present invention to provide a hydraulic control method and a hydraulic control device for an automatic transmission that can perform the control.

[0005]

In order to achieve the above object, at least a throttle opening sensor, a vehicle speed sensor for detecting a vehicle speed, a shift position switch for detecting a shift position, and a signal from each of the sensors and switches. And a line pressure solenoid to which a signal is input from the hydraulic control means, wherein the shift position signal is shifted from a neutral range to the hydraulic control means. A line pressure control unit is provided for setting the line pressure at the time of shifting to a different line pressure according to the number of shift stages when switching to the drive range.

[0006] With this configuration, when the signal of the shift position switch is switched from the neutral range to the drive range, the line pressure can be set according to the configured shift speed. And the shock due to fastening of the friction element is eliminated. Further, in addition to the above-described configuration, the hydraulic control unit is provided with a shift solenoid abnormality determination unit and a vehicle speed sensor abnormality determination unit to detect abnormality of the shift solenoid and the vehicle speed sensor,
Since the number of gears at which the fail-safe operation can be performed is selected and the line pressure can be set in accordance with the gear, the engagement time of the friction element becomes longer and the shock due to the engagement of the friction element is eliminated.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. As shown in FIG. 2, the hydraulic control device for an automatic transmission according to the present embodiment uses a line pressure-actuated friction element to control the power transmission path of the automatic transmission 2 connected to the output shaft of an engine 1 such as a four-wheel vehicle. It switches. Here, the automatic transmission 2 is, as shown in FIG.
The planetary gear mechanism 20 to which torque is transmitted from a torque converter (not shown) is a main part and includes two planetary gear sets and six friction elements. The two planetary gear sets are interposed between an input shaft 21 to which rotational power is transmitted from a torque converter and an output shaft 22 to transmit reduced rotational power to a propeller shaft side (not shown). It is arranged in. The two planetary gear sets are known front carrier 23, rear carrier 24, front internal gear 25, rear internal gear 26, front pinion 27, rear pinion 28, front sun gear 29,
And a rear sun gear 30 (see FIG. 3). As shown in FIG. 3, the friction element described above includes a low clutch 31 of a wet-type multi-plate clutch for intermittently connecting the rear internal gear 26 and the front carrier 23, and the front carrier 2
3, a low and reverse brake 32 of a wet multi-plate brake, a high clutch 33 of a wet multi-plate clutch for intermittently connecting the input shaft 21 and the front carrier 23, and a wet multi-plate clutch for intermittently connecting the input shaft 21 and the front sun gear 29. Reverse clutch 3
4, a band brake 35 of a band type brake for fixing the front sun gear 29, and a low one-way clutch 36 of a sprag type one-way clutch for fixing the front carrier 23. For example, when a three-stage command is issued from the hydraulic control means 6 described later, first, the high clutch 33 and the low clutch 31 are connected, and thereafter, the rotational power input to the input shaft 21 becomes high. The power is transmitted to the rear internal gear 26 via the clutch 33. The rotational power of the rear internal gear 26 is transmitted to the rear sun gear 30 via the rear pinion 30, whereby the rear internal gear 26 and the rear sun gear 30 rotate at the same speed. And
The rear carrier 24 pivotally supported by the rear pinion 28 also rotates at the same speed, and rotational power at the same speed is output from the output shaft 22 joined to the rear carrier 24.

Next, a hydraulic circuit for switching the friction elements will be described with reference to FIG. Here, the same reference numerals are used when the line pressures are equal. First, the manual valve 46 shown in FIG.
It is possible to manually select a reverse position R used for back traveling, a neutral position N for putting the friction element in a free state, or a drive position D, second position 2 and first position 1 used for forward traveling from the driver's seat. I have. Here, when the drive position D is selected, one to four stages are selectively controlled by the hydraulic control means 6, which will be described later, according to the vehicle traveling state. As shown in FIG. 4, the first stage is selected by applying the line pressure L2 to the low clutch 31 of the above-mentioned friction elements. Further, at the time of one-stage acceleration, the low one-way clutch 36 is connected. The second stage is selected when the line pressure L2 acts on the low and reverse brake 32 and the band brake 35 among the aforementioned friction elements. The third stage is a low clutch 31 of the aforementioned friction elements.
And the high clutch 33 is actuated by the line pressure L2. The fourth gear is selected by the line pressure L2 acting on the high clutch 33 and the band brake 35 among the friction elements described above.

As shown in FIG. 4, the hydraulic circuit for switching the friction element includes a pressure regulator valve 40 for adjusting the oil pump discharge pressure discharged from the pump to an optimum line pressure L2 according to the running state of the vehicle. By switching the oil passage of the line pressure L2 controlled to the optimum pressure by the regulator valve 40 in three directions, the friction elements 3
The first and second shift valves 41 and 42 for controlling the first, second, and third shift valves 41 and 42 are controlled by the pilot pressure according to operating conditions such as vehicle speed and accelerator opening. It is roughly constituted by first or second shift solenoids 12 and 13 switched by L3, and pipes 50 to 64 connecting the respective valves.
The above-described pressure regulator valve 40 is controlled by the line pressure solenoid 14 via a pressure modifier valve 43. This is because the pressure regulator valve 40 is connected to the pressure modifier pressure L sent from the pressure modifier valve 43.
5 and the pressure modifier valve 43
Is controlled by the throttle pressure L4 sent from the line pressure solenoid 14. Further, the first or second shift valve 41, 42 is controlled by switching the pilot pressure L3 controlled to an appropriate pressure by the pilot valve 44 by the first or second shift solenoid 12, 13.

Hereinafter, the operation of each of the above-described valves will be described in order. In a pressure regulator valve 40 (disclosed at the lower left in the figure) controlled by the line pressure solenoid 14, an oil pump discharge pressure from a pipe line 50 connected to a port 40a acts to push up a valve body 40b upward. ing. Further, the urging force of the spring body 40c and the pressure modifier pressure L5 from the conduit 51 connected to the port 40d via the pressure regulator plug 40e act to push down the valve body 40b. As a result, when the oil pump discharge pressure becomes larger than the urging force of the spring body 40c and the pressure modifier pressure L5, the valve body 40b is pushed upward, and the pipeline 52 connected to the port 40f.
Drained from Therefore, the line pressure L2 is controlled according to the pressure modifier pressure L5.

Next, a pilot pressure L3 is supplied to a pilot valve 44 provided in parallel with the pressure regulator valve 40 through a pipe 53 connected to a port 44a.
Acts to push the valve body 44b downward. On the other hand, the biasing force of the spring body 44c acts to push the pilot valve 44 upward. Then, the line pressure L2 flowing from the pipe line 54 connected to the port 44d acts to push down the valve body 44b, whereby the valve body 44b is pushed downward and is drained from the drain port indicated by the symbol X. Is pushed down. As a result, the line pressure L2 is
The pressure is adjusted so as to be balanced with c, and becomes the pilot pressure L3.

As shown in FIG. 4, a pilot pressure L3 acts on a port 14a from a pipe 53 on the line pressure solenoid 14 for controlling the pressure modifier valve 43, and the amount of depression of the solenoid 14c by the accelerator pedal is determined. Is turned on or off according to the vehicle information of the vehicle, the throttle pressure L4 of the pipeline 55 connected to the port 14b is
Is controlled. In addition, a throttle pressure L4
And a throttle pressure accumulator 45 for reducing the vibration of the throttle valve.

The urging force of the spring body 43c and the throttle pressure L4 of the line 55 connected to the port 43d are applied to the pressure modifier valve 43 by the valve body 43b.
Acts upward. The pilot pressure L3 is supplied from a pipe 53 connected to the port 43a.
Acts to push down the valve body 43b and is pushed up until it is drained from the drain port X. Thus, the pilot pressure L3 flowing from the port 43a becomes
The urging force of the spring body 43c and the line pressure solenoid 14
The pressure is adjusted to a pressure modifier pressure L5 that is balanced with the throttle pressure L4 output in step (1).

The first shift valve 41 has a spring 41
The urging force by a acts to push downward. Also,
The first shift solenoid 12 acts to push the pilot pressure L3 upward from the pipe line 57 connected to the port 41b. Then, the first shift solenoid 12
Is ON, a pilot pressure L3 is generated in the conduit 57 and acts on the valve body 41c to push the valve body 41c upward. When the first shift solenoid 12 is off, the pilot pressure L3 is not generated in the pipeline 57, and the valve is pushed downward by the urging force of the spring body 41a.
Thus, the flow path of the line pressure L2 is switched by moving the valve main body 41c in the vertical direction. By the cooperation of the first shift valve 41 and a second shift valve 42 described later, the flow path of the line pressure L2 is switched, and the friction elements 31 to 35 are selectively engaged.

The second shift valve 42 has a spring 42
The urging force by a acts to push downward. Also,
The pilot pressure L3 acts to push upward from the pipe line 58 connected to the port 42b by the second shift solenoid 13. Then, when the second shift solenoid 13 is turned on, a pilot pressure L3 is generated in the pipe line 58 and acts on the valve body 42c to push the valve body 42c upward. When the second shift solenoid 13 is off,
Since no pilot pressure L3 is generated in the conduit 58, the valve is pushed downward by the urging force of the spring body 42a. As described above, by moving the valve body 42c in the vertical direction,
The flow path of the line pressure L2 is switched. By the cooperation of the second shift valve 42 and the above-described first shift valve 41, the flow path of the line pressure L2 is switched, and the friction elements 31 to 35 are selectively engaged. The first and second shift valves 41 and 42 are connected to the line 54 and the line 5 of the line pressure L2 regardless of the first and second shift solenoids 12 and 13.
It is also possible to switch by a manual valve 46 connected between. When the reverse mode R is selected by the manual valve 46, the line pressure L2 flows through the line 62, the reverse clutch 34 is operated, the line pressure L2 flows through the line 60, and the low and reverse brake 32 is operated. I do.

First and second shift solenoids 12, 1
3 is provided between the pilot valve 44 and the first and second shift valves 41 and 42. Port 12
a, pilot pressure L3 from line 53 connected to 13a.
When the solenoids 12b and 13b are energized (ON) or de-energized (OFF) based on information from hydraulic control means to be described later, pilots to the pipes 57 and 58 connected to the ports 12c and 13c are provided. The pressure L3 is controlled. When the first shift solenoid 12 is turned on and the second shift solenoid 13 is turned on, one stage is established. In the first stage, the low clutch 31 of the friction elements operates. This is because when the first shift solenoid 12 is on, the pilot pressure L3
Occurs, and the valve body 41c of the first shift valve 41
To push the valve body 41c upward. Also,
When the second shift solenoid 13 is turned on, a pilot pressure L3 is generated in the pipeline 58 and acts on the valve body 42c of the second shift valve 42 to push the valve body 42c upward. Then, the line pressure L2 flowing from the pipe 56 connected to the port 42h flows through the pipe 59 connected to the port 42i, and operates the low clutch 31. here,
In the case of the L range, the manual valve 46 moves rightward in the drawing, and the line pressure L2 flows into the pipe 65, and the port 41
e, flows into port 42d via port 41f and port 4d.
The low and reverse brake 32 is operated by flowing through the pipeline 60 connected to 2e.

Next, the first shift solenoid 12 is turned off,
When the second shift solenoid 13 is turned on, two stages are established. In the second stage, the low clutch 31 and the band brake 35 among the friction elements operate. This is the first shift solenoid 12
Is off, the pilot pressure L3 is not generated in the pipeline 57, so that the valve body 41c of the first shift valve 41 is pushed downward by the urging force of the spring body 41a. When the second shift solenoid 13 is turned on, a pilot pressure L3 is generated in the pipe line 58 and acts on the valve body 42c of the second shift valve 41 to push the valve body 42c upward. The line pressure L2 flowing from the pipe 56 connected to the port 42h is applied to the line 5 connected to the port 42i.
9, the low clutch 31 is operated. Further, the line pressure L2 flows from the conduit 56 connected to the port 41g to the conduit 63 connected to the port 41h, acts on the apply side of the band brake 35, and operates the band brake 35.

When the first shift solenoid 12 is off and the second shift solenoid 13 is off, three stages are established. In the third stage, the low clutch 31 and the high clutch 33 of the friction elements operate. This is because, when the first shift solenoid 12 is off, the pilot pressure L3 does not occur in the pipe line 57, so that the valve body 41c of the first shift valve 41 has the spring body 41a.
It is pushed downward by the urging force of. Further, since the second shift solenoid 13 is off and the pilot pressure L3 is not generated in the pipe line 58, the valve body 4 of the second shift valve 42
2c is pushed downward by the urging force of the spring body 42a.
The line pressure L2 flowing from the pipe 56 connected to the port 42i flows through the pipes 59 and 64 connected to the port 42i via the ports 41k and 42j, and operates the low clutch 31. , Acting on the release side of the band brake 35. Further, the line pressure L2 flowing from the pipe 56 connected to the port 42i flows into the pipe 63 connected to the port 41h and acts on the apply side of the band brake 35. Is released. In addition, port 4
Line pressure L2 flowing from the pipeline 56 connected to 2f
Flows through the pipe line 61 connected to the port 42g to operate the high clutch 33.

When the first shift solenoid 12 is turned on and the second shift solenoid 13 is turned off, there are four stages. In the fourth gear, the high clutch 33 and the band brake 35 among the friction elements are operated. That is, when the first shift solenoid 12 is turned on, a pilot pressure L3 is generated in the pipe line 57 and acts on the valve main body 41c of the first shift valve 41 to push the valve main body 41c upward. Further, since the second shift solenoid 13 is off and no pilot pressure L3 is generated in the pipeline 58, the valve body 42c of the second shift valve 42 is pushed downward by the urging force of the spring body 42a. And
The line pressure L2 flowing from the pipe 56 connected to the port 42f flows through the pipe 61 connected to the port 42g, and operates the high clutch 33. Further, the line pressure L2 flowing from the pipe line 61 connected to the port 41d is applied to the port 41d.
h flows into the pipe 63 connected to the
And actuate the band brake 35.

Next, the hydraulic control device for the automatic transmission will be described in detail. As shown in FIG. 2, the hydraulic control device for the automatic transmission includes a throttle opening sensor 3 for detecting a throttle opening, a vehicle speed sensor 4 for detecting a vehicle speed, and a shift position switch 5 for detecting a shift position. A hydraulic control means 6 in which signal lines of respective sensors and switches are connected to an input side, and an automatic transmission in which a signal line is connected to an output side of the hydraulic control means 6 and connected to an output shaft of the engine 1. The above-mentioned first and second shift solenoids 12 and 13 for switching the friction elements (reference numerals 31 to 36 in FIG. 3), and the line pressure solenoid 14 for determining the line pressure of the friction elements (reference numeral L2 in FIG. 4). Is provided.

As the throttle opening sensor 3, a potentiometer type throttle opening sensor or the like which is provided in a throttle portion of the engine 1 and outputs a signal of a voltage corresponding to the throttle opening of the engine 1 is used. The signal output from the throttle opening sensor 3 is input to the input side of the hydraulic control means 6.

The vehicle speed sensor 4 is provided on the output shaft of the automatic transmission 2 and uses a reed switch or the like which repeats on and off by a magnet rotating with the output shaft. The signal S4 output from the vehicle speed sensor 4 is input to the input side of the hydraulic control means 6.

The shift position switch 5 is provided near the manual valve so as to detect a shift position selected by a shift knob (connected to the manual valve 46 in FIG. 4) at hand of the driver. The detected shift position signal S5 is input to the input side of the hydraulic control means 6. Here, the shift knob is used to set a parking position P used for parking, a reverse position R used for reverse running, a neutral position N for setting a friction element to a free state, or a drive position D used for forward running, and a second position 2. First position 1 can be selected. When the drive position D is selected, the first to fourth gears are selectively controlled by the hydraulic control means 6 according to the vehicle traveling state.

The first and second shift solenoids 12,
Reference numeral 13 denotes a hydraulic circuit for switching the friction element of the automatic transmission connected to the output shaft of the engine 1 as described above (see FIG. 4). Specifically, the pilot valve 44 and the first and second shift valves 41 and 42 are provided. The shift solenoids 12 and 13 are turned on (O
By controlling N) and off (OFF), the first and second shift valves 41 and 42 are controlled, and the number of gears is determined. First and second shift solenoids 12, 13
Is connected to the output side of the hydraulic control means 6, and is turned on and off by a signal from the hydraulic control means 6. Here, ON indicates a state in which the excitation coils of the first and second shift solenoids 12 and 13 are energized. OFF indicates that the excitation coils of the first and second shift solenoids 12 and 13 are not energized.

The line pressure solenoid 14 controls the line pressure L2 according to a signal from the hydraulic control means 6. The line pressure solenoid 14, as shown in FIG.
3 is actuated, and the port 1 is
The throttle pressure L4 of the pipe line 55 connected to the valve 4b is controlled. The pressure modifier pressure L5 is adjusted by the pressure modifier valve 43 so as to balance the throttle pressure L4. The pressure regulator valve 4 according to the pressure modifier pressure L5
At 0, the line pressure L2 is controlled. The signal line of the line pressure solenoid 14 is connected to the output side of the hydraulic control means 6.

As shown in FIG. 1, the hydraulic control means 6 includes a gear position determining section 8 for determining a gear position based on a signal (information) S3 of the throttle opening sensor 3 and a signal (information) S4A of the vehicle speed sensor 4, and the like. Signal (information) S4 from the vehicle speed sensor 4
B is input, a vehicle speed sensor abnormality determination unit 7 that determines abnormality of the vehicle speed sensor 4, a shift solenoid abnormality determination unit 9 that determines abnormality of the first shift solenoid 12 and the second shift solenoid 13, and a gear position determination The signal (information) S8A from the section 8 and the signal (information) from the shift position switch 5
A signal S8B from the line pressure control unit 10 which receives the signal S5 to control the line pressure solenoid 14, and a gear position determination unit 8.
Is input to control the first shift solenoid 12 and the second shift solenoid 13. The hydraulic control means 6 generally includes a central processing unit (CPU) for determining and processing information, a medium for storing information (a so-called ROM, RAM), a signal input unit such as a vehicle speed sensor S4, and the like. For example, a board computer having an output unit (so-called driver) for outputting a signal is used. The number of transmission stages corresponding to the engine load and the vehicle speed, that is, a shift map and the like are stored in the ROM serving as a medium.

The signal S3 of the throttle opening sensor 3 and the signal S4 of the vehicle speed sensor 4 are input to the gear position determination unit 8 from the input side of the hydraulic control unit 6. The gear position determination unit 8 compares the signal S3 of the throttle opening sensor 3, the engine load information and the vehicle speed information received by the signal S4 of the vehicle speed sensor 4, with the shift map stored in the storage medium. , The gear position is appropriately determined. Further, the signal S7 of the vehicle speed sensor abnormality determination unit 7 and the signal S9 of the shift solenoid abnormality determination unit 9 are input to the gear position determination unit 8. When an abnormality of the vehicle speed sensor 4 is input based on the signal S7 of the vehicle speed sensor abnormality determination unit 7, a process for setting an appropriate shift speed is performed in order to perform a fail-safe (described later) when the vehicle speed sensor is abnormal. Do. The appropriate shift speed is, for example, three speeds. On the other hand, according to the signal S9 of the shift solenoid abnormality determination unit 9, the shift solenoids 12, 1 that have become inoperable due to disconnection, ground short-circuit, etc.
3 is input. The shift speed determining unit 8 determines the number of shift speeds that can be actually configured by the shift solenoids 12 and 13 and that is appropriate for performing the fail-safe operation. Here, the fail-safe operation is a control operation that prevents suddenly lowering the number of gears and suddenly applying engine brake, or rapidly increasing the number of gears so that the vehicle cannot travel on an uphill. That means. For example, in the speed change mechanism shown in the chart of FIG. 5, when the shift speed on the map is one, the first shift solenoid 12 is turned on,
A command to turn on the second shift solenoid 13 is issued.
At this time, if the second shift solenoid 13 is abnormal, the first shift solenoid 12 is turned on and the second shift solenoid 13 is turned off, and the valve is actually in a four-stage state. At this time, the first shift solenoid 12 is turned off, so that a three-stage state is established. As a result, the state in which the vehicle cannot suddenly become unable to travel uphill is eliminated, and the fail-safe operation can be performed.

The vehicle speed sensor abnormality judging section 7 detects a case where a signal from the shift position switch is higher than a predetermined engine speed and a vehicle speed signal is not input in a state where the shift range is the traveling range, and judges that the vehicle is abnormal.

The shift solenoid abnormality judging unit 9 judges disconnection or short circuit (ground short) by comparing the signals S11A and S11B from the shift control unit 11 with the actual signal level. The shift solenoid abnormality determination unit 9
Although it is possible to perform software processing by the above-described CPU, ROM, and RAM, it may be configured in hardware by a logic circuit such as an operational amplifier.

As shown in FIG. 1, a signal S8A of the gear position determination unit 8 and a signal S5 of the shift position switch 5 are input to the line pressure control unit 10, as shown in FIG. Among them, based on the gear position input by the signal S8A of the gear position determination unit 8,
The line pressure is determined. The determined line pressure signal S10 is output from the line pressure control unit 10 to the line pressure solenoid 14. The line pressure control by the line pressure control unit 10 is performed according to different line pressure tables at the time of shifting and at the time of non-shifting.

During shifting, the shift position switch 5
When the shift from N to D is detected based on the signal S5, the line pressure is controlled as shown in the diagram of FIG. 6A in accordance with the speed input by the signal S8A of the speed determination unit 8. Control is performed so that the line pressure N1 in the N range becomes the line pressure D1, D2, D3, and D4 in the D range. Line pressures D1, D2, D corresponding to the respective shift speeds
3, D4 are the respective transient line pressure setting times T1, T2,
After T3 and T4, control is performed so that the line pressure becomes the normal line pressure D5.

A diagram D1 shows a line pressure when a shift is determined from N to 1st stage, a diagram D2 shows a line pressure when a shift is determined from N to 2nd stage, and a diagram D3 shows a shift determination from N to 3rd stage. The line pressure at the time of the shift and the diagram D4 show the line pressure at the time when the shift is determined from N to 4th. The lower the number of stages (for example, one stage) is selected, the longer the transient line pressure setting time (for example, T1) at a lower pressure. In addition, a high number of stages (for example, 4
The higher the pressure, the shorter the transient line pressure setting time (for example, T4) at a higher pressure. Line pressure (D
1, D2, D3, D4) are determined according to the engine load, as shown in the diagram of FIG. 6B, the horizontal axis represents the engine load, and the vertical axis represents the line pressure (N / m).
² ) shows a line pressure table designated as ² ). Line pressure (D1,
D2, D3, and D4) are set to a higher pressure as the engine load increases.

Another embodiment of the present invention will be described. In this case, the hardware configuration is the same as the above-described conventional example, and the control method is changed. As shown in the diagram of FIG. 7, the line pressure at the time of N → D selection is controlled so as to decrease (TP) after increasing the above-described line pressure and then gradually increase (TS). Apply. In this case, the line pressure is increased and then decreased according to the number of gears (TP). Thereby, the preparation for fastening the friction element is performed. Thereafter, the line pressure is gradually increased in accordance with the number of gears (TS). Thereby, the friction element is completely fastened. In this case, the magnitude of the precharge pressure to be decreased after the line pressure is increased, the time for generating the precharge pressure, and the hydraulic pressure increase rate at which the line pressure is gradually increased thereafter are changed according to the number of shift steps. It is set for each stage. As a result, the line pressure can be set according to the gear stage to be configured, so that the engagement time of the selected friction element is lengthened, and the shock due to the engagement of the friction element is eliminated. Further, in addition to the above-described configuration, the hydraulic control unit is provided with a shift solenoid abnormality determination unit and a vehicle speed sensor abnormality determination unit, so that the engagement time of the friction element becomes longer due to abnormality of the shift solenoid and the vehicle speed sensor, Shock due to fastening of the friction element is eliminated.

FIG. 8 is a flowchart showing a part of the control contents of the control device for the automatic transmission according to the present embodiment. The process shown in this flowchart is started at regular intervals using a timer interrupt process that interrupts the main program at regular time intervals. First, the shift position is fetched from the signal S5 of the shift position switch 5 (step S10).
0) Then, the load of the engine 1 is acquired from the signal S3 of the throttle opening sensor 3 (step S101), and the vehicle speed is acquired from the signal S4 of the vehicle speed sensor 4.
(Step S102)

Subsequently, the abnormality of the vehicle speed sensor 4 is determined.
As a determination method, the signal S4 of the vehicle speed sensor 4 when the engine speed is equal to or higher than a predetermined engine speed in the shift position or the traveling range state.
Is detected, it is determined that there is an abnormality (step 103).

Further, it is determined whether the first and second shift solenoids 12 and 13 are abnormal. As a determination method, disconnection or short circuit is determined by comparing a signal to be output with an actual signal level. (Step 10
4).

Next, based on the result of the abnormality determination of the vehicle speed sensor in step 103, the process proceeds to step 110 if the vehicle speed sensor is abnormal, and proceeds to step 106 if the vehicle speed sensor is not abnormal. (Step 105)

In step 110, in order to execute a fail-safe operation when the vehicle speed sensor is abnormal, a process for setting the gear stage to three speeds is performed.

In step 106, the shift speed on the shift map (the shift speed on the map) is determined from the vehicle speed and the engine load according to a shift map set in advance.

Next, based on the result of the shift solenoid abnormality determination in step 104, the first shift solenoid 12
Alternatively, if the second shift solenoid 13 is abnormal, the process proceeds to step 109. If not abnormal, that is, if the second shift solenoid 13 is normal, the process proceeds to step 108. (Step 107)

In step 108, if the first shift solenoid 12 or the second shift solenoid 13 is not abnormal in step 107, that is, if it is determined that it is normal,
The shift speed on the map is used as it is.

In step 109, if it is determined in step 107 that the first shift solenoid 12 or the second shift solenoid 13 is abnormal, the gear position in the case of a shift solenoid abnormality is determined. The shift speed is determined based on the type of malfunctioning shift solenoid and the shift speed on the map.
Perform as shown in 1.

Next, it is determined whether or not the selection is from the N range to the D range. If the selection is not from the N range to the D range, the process proceeds to snub 117. If the selection is from the N range to the D range, the step is performed. Proceed to 112. (Step 111)

In step 117, N
When it is determined that the selection is not from the range to the D range, a line pressure for performing normal line pressure control is calculated.

In step 112, N
When it is determined that the selection is from range to D range,
A branch to a different control is determined depending on the shift speed determined in step 109. If the shift is from the N range to the first gear, the process proceeds to step 113; if the shift is from the N range to the second gear, the process proceeds to step 114; if the gear is shifted from the N range to the third gear, the process proceeds to step 115. , 4 from N range
In the case of shifting to a gear, the process proceeds to step 116. (Step 112)

In step 113, the line pressure from the N range to the first stage is calculated. The shift from the N range to the first gear occurs when the vehicle is stopped or at a low vehicle speed, and the selection from the N range to the D range is made. The method of calculating the line pressure is such that the line pressure for shifting from the N range to the first stage which is preset according to the engine load is set during the transient line pressure setting time for the speed from the D range to the first stage preset. Retrieve the line pressure from the data table. The normal line pressure is set after the transient line pressure setting time.

In step 114, the speed line pressure from the N range to the second stage is calculated. Calculation method is 1 from N range
This is the same as the stepped shift, except that the transient line pressure setting time and the line pressure data table have values separately set to two steps from the N range. (Step 114)

In steps 115 and 116, the line pressure is calculated using the value set separately. Next, a line pressure control signal is output based on the calculated line pressure. (Step 118) As described above, when the range is switched from the neutral range to the drive range, the line pressure during shifting is controlled according to the number of shift steps.

[0049]

According to the present invention, a line pressure control unit is provided for setting the line pressure during shifting to a different line pressure in accordance with the number of shift stages when the shift position signal is switched from the neutral range to the drive range. As a result, the line pressure can be set according to the configured shift speed, so that the engagement time of the friction element is prolonged, and the shock due to the engagement of the friction element is eliminated. Further, in addition to the above-described configuration, the hydraulic control unit is provided with a shift solenoid abnormality determination unit and a vehicle speed sensor abnormality determination unit, so that the engagement time of the friction element becomes longer due to abnormality of the shift solenoid and the vehicle speed sensor, Shock due to fastening of the friction element is eliminated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

2 is a hydraulic control device for an automatic transmission disclosed in FIG. 1,
FIG. 2 is a system diagram showing a relationship between an engine and an automatic transmission.

FIG. 3 is a perspective view of the automatic transmission disclosed in FIG. 1;

FIG. 4 is a hydraulic circuit diagram of the automatic transmission disclosed in FIG.

FIG. 5 is a table of shift speeds determined by hydraulic control means when the shift solenoid of the automatic transmission disclosed in FIG. 1 is normal and abnormal.

6 is a time chart and a line pressure table of the hydraulic control device for the automatic transmission shown in FIG. 1, wherein FIG.
FIG. 6B is a diagram showing a time chart when the range is shifted to D, and FIG. 6B is a diagram showing a line pressure table used in the time chart of FIG. 6A.

FIG. 7 is a diagram showing a time chart when a range is shifted from N to D according to another embodiment of the present invention.

FIG. 8 is a flowchart showing an operation of the hydraulic control device for the automatic transmission shown in FIG.

[Description of Signs] 1 Engine 2 Automatic transmission 3 Throttle opening sensor 4 Vehicle speed sensor 5 Shift position switch 6 Hydraulic control means 7 Vehicle speed sensor abnormality determination unit 8 Shift stage determination unit 9 Shift solenoid abnormality determination unit 10 Line pressure control unit 11 Transmission control unit 12 First shift solenoid 13 Second shift solenoid 14 Line pressure solenoid

Claims (9)

[Claims] 1. A hydraulic control method for an automatic transmission for controlling a line pressure during a shift of an automatic transmission to a pressure different from a non-shift speed based on at least vehicle speed information, throttle opening information, and shift position information. A hydraulic pressure control method for an automatic transmission, characterized in that when information is switched from a neutral range to a drive range, the line pressure during shifting is set to a different line pressure according to the number of gears. 2. A hydraulic control method for an automatic transmission, comprising: controlling a line pressure during a shift operation of an automatic transmission to a pressure different from a non-shift operation based on at least vehicle speed information, throttle opening information, and shift position information. A hydraulic pressure control method for an automatic transmission, characterized in that when information is switched from a neutral range to a drive range, a line pressure at the time of shifting is set to a different line pressure according to the number of shift stages and a throttle opening. 3. A hydraulic pressure control method for an automatic transmission for controlling a line pressure during a shift of an automatic transmission to a pressure different from a non-shift speed based on at least vehicle speed information, throttle opening information, and shift position information. A hydraulic pressure control method for an automatic transmission, characterized in that when information is switched from a neutral range to a drive range, the line pressure at the time of shifting is lower when the number of gears is lower than when the number of gears is higher. 4. A hydraulic control method for an automatic transmission for controlling a line pressure during a shift of an automatic transmission to a pressure different from a non-shift speed based on at least vehicle speed information, throttle opening information and shift position information. When the information is switched from the neutral range to the drive range, the line pressure at the time of shifting is increased according to the number of shift speeds, then decreased, and thereafter, the line pressure is gradually increased according to the number of shift speeds. A hydraulic control method for an automatic transmission. 5. A hydraulic pressure control method for an automatic transmission that controls a line pressure at the time of shifting of the automatic transmission to a pressure different from that during non-shifting based on at least vehicle speed information, throttle opening information, and shift position information. It is determined whether the vehicle speed information is normal, and when the shift position information is switched from the neutral range to the drive range, if the determination is not normal, a predetermined number of steps is selected, and according to the selected number of steps, A hydraulic pressure control method for an automatic transmission, wherein a line pressure during a gear shift is set to a different line pressure. 6. A hydraulic pressure control method for an automatic transmission that controls a line pressure during shifting of the automatic transmission to a pressure different from that during non-shifting based on at least vehicle speed information, throttle opening information, and shift position information. It is determined whether or not the shift solenoid is normal, and when the shift position information is switched from the neutral range to the drive range, the number of selectable shift steps is selected when the determination is not normal, and according to the selected step number. A hydraulic pressure control method for an automatic transmission, comprising setting a line pressure during shifting to a different line pressure. 7. At least a throttle opening sensor, a vehicle speed sensor for detecting a vehicle speed, a shift position switch for detecting a shift position, hydraulic pressure control means for receiving signals from the respective sensors and switches, and the hydraulic pressure control means. And a line pressure solenoid to which a signal is input from a hydraulic pressure control device for an automatic transmission, wherein the hydraulic control means, when a shift position signal of a shift position switch is switched from a neutral range to a drive range, A hydraulic control device for an automatic transmission, comprising: a line pressure control unit that sets a line pressure during shifting to a different line pressure according to the number of gears. 8. At least a throttle opening sensor, a vehicle speed sensor for detecting a vehicle speed, a shift position switch for detecting a shift position, hydraulic control means for receiving a signal from each sensor and switch, and the hydraulic control means. And a line pressure solenoid to which a signal is input from a vehicle speed sensor abnormality determining unit that determines in advance whether the vehicle speed signal of the vehicle speed sensor is normal. In addition, when the shift position signal of the shift position switch is switched from the neutral range to the drive range, if the determination by the vehicle speed sensor abnormality determination unit is not normal, a predetermined number of steps is selected, and the selected number of steps is selected. An automatic transmission having a line pressure control unit for setting a line pressure during shifting to a different line pressure according to the number of gears; Hydraulic control device. 9. At least a throttle opening sensor, a vehicle speed sensor for detecting a vehicle speed, a shift position switch for detecting a shift position, hydraulic control means for receiving signals from the respective sensors and switches, and the hydraulic control means A hydraulic pressure control device for an automatic transmission, comprising: a line pressure solenoid to which a signal is input from; and a shift solenoid to which a signal is input from the hydraulic pressure control means, wherein the hydraulic pressure control means has the shift solenoid in advance. A shift solenoid abnormality determining unit for determining whether the shift solenoid switch is normal is provided.When the shift position signal of the shift position switch is switched from the neutral range to the drive range, the shift solenoid abnormality determining unit is not normal. Select the number of selectable gears, and adjust the line pressure during shifting according to the selected gear. Providing the line pressure control section is set to become the line pressure hydraulic control system for an automatic transmission according to claim.