JP3429057B2 - Transmission control device for automatic transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission, and more particularly to a technique for detecting and determining the position of a control lever which performs a shift operation.

[0002]

2. Description of the Related Art Conventionally, as a technique for detecting the position of a control lever in a shift control device of an automatic transmission, for example, a technique disclosed in Japanese Utility Model Laid-Open No. 62-147755 is known.

In this prior art, a neutral switch for detecting a selection operation of a neutral range of a control lever, a range detection switch group for detecting a selection operation of another traveling range of a control lever, and a detection operation of these switches. The structure is provided with a shift control means for controlling a shift and a neutral determination means for determining the neutral range position when none of the switches generate a detection signal. Therefore, even if the control lever is arranged at a position where none of the switches generate a detection signal, it is not judged as an error and the shift control of the shift control means is not stopped.

[0004]

By the way, in the automatic shift control device, in response to the selection operation of the control lever,
Various controls other than gear shifting are performed, for example,
As described in JP-A-3-28571,
At the time of switching from the neutral range to the running range by inputting a range signal, the hydraulic fluid pressure is temporarily raised and then rapidly lowered to perform the precharge control to make a shelf pressure for precharging. However, when the neutral range signal is disconnected, it is not possible to detect when the neutral range is switched to the running range, and this precharge control is not performed.

Therefore, if the above-mentioned conventional technique is applied to this technique to determine the neutral range when there is no signal, even if the neutral range signal is disconnected, the rack is switched when switching from the neutral range to the traveling range. Precharge control for forming pressure becomes possible.

However, in the range detection switch group such as the inhibitor switch, between the N range and the D range, between the D range and the second speed range, or between the second speed range and the first range.
There is a no signal region between the speed ranges, and the neutral determination means determines the neutral range in this no signal region. For example, when switching from the 2nd speed range to the D range, the 2nd speed range → It will be determined from N range to D range. Therefore, the precharge control is performed even between the second speed range and the D range,
There arises a problem that the shift shock becomes worse.

The present invention has been made by paying attention to the above-mentioned conventional problems, and it is possible to cope with the disconnection of the neutral range signal while preventing a problem from occurring in the no signal region between the traveling ranges. Has an aim.

[0008]

In order to achieve the above-mentioned object, the present invention, as shown in the claim correspondence diagram of FIG. 1, has a control lever a for performing a selection operation of a neutral range and a travel range, and this control. Automatic shift control including a range detection switch b for detecting the neutral range of the lever a and each traveling range, and a shift control means d for performing shift control of the automatic transmission c and its related control based on the detection of the range detection switch b. In a shift control device for a machine, when the shift control means d has a state in which the range detection switch b does not generate a detection signal, it is determined that the state is the immediately preceding range position within a predetermined time, and the state is determined. Is provided for a predetermined time or more, the range determination means e for determining the neutral range is provided.

The shift control means d performs precharge control for temporarily increasing the hydraulic fluid pressure and then rapidly lowering the hydraulic fluid pressure to produce a shelf pressure for precharging when switching from the neutral range to the travel range. It may be performed.

[0010]

When the range is switched from one range to another range, the range detection switch b is in a non-signal state in which no detection signal is generated for a short time. Therefore, the range determination means e
Since the non-signal state is within a predetermined time, it is determined that the range is immediately before during this non-signal state. Explaining this concretely, for example, when the control lever a is selectively operated from the 2nd speed range to the drive range, the detection state of the range detection switch b changes from 2nd speed range detection → no signal → drive range detection. , The range determination means e,
Second speed range detection → It is judged as the second speed range while there is no signal,
When the drive range is detected, the drive range is determined, and the second speed range → neutral range → drive range is not determined. Therefore, in the device according to the second aspect, the precharge control is not performed when there is no signal.

When the control lever a is operated to the neutral range when the neutral signal of the range detection switch b is disconnected, the detection signal is not output from the range detection switch b and the signal is in a no signal state. In the case of e, the neutral range is determined because the no-signal state is longer than the predetermined time. For example, when operating from the drive range to the neutral range,
The detection state of the range detection switch b changes from drive range → short-time no signal between ranges → long-term no signal due to neutral range disconnection, and the range determination means e changes the drive range from the drive range to a predetermined time thereafter. Although it is determined, it is determined to be in the neutral range after a predetermined time has elapsed. In this way, the shift control means d does not stop the shift determination even if the no-signal time is long, so that the control by the shift control means d is continued and the problem of stopping the control does not occur. . Further, even if the neutral signal is disconnected as described above, the neutral range is determined when the neutral range is operated. Therefore, in the apparatus according to claim 2, the neutral range is switched to the driving range such as the drive range. When this occurs, the determination according to this switching is made and precharge control is performed.

[0012]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a system diagram showing an automatic shift control device according to an embodiment of the present invention, in which 1 is an A / T control unit for controlling the shift of an automatic transmission AT and 10 is an engine for controlling the drive of an engine E. The control unit is shown.

This engine control unit 10
Is basically a signal from the engine speed sensor 5 for detecting the engine speed, a signal from a water temperature sensor (not shown) for detecting the engine cooling water temperature, and a throttle opening corresponding to the engine load. After inputting a signal from the throttle sensor 4 to calculate the fuel injection amount, the operation of the fuel injection valve (not shown) is controlled for a time corresponding to this.

In the automatic transmission AT, hydraulic pressure is supplied to and discharged from a control valve CV to a friction engagement element (not shown) such as a clutch and a brake, which is provided in the automatic transmission AT to engage or disengage them. The control valve CV is a well-known device that switches a gear ratio, and a manual valve (not shown) for switching a circuit that supplies a line pressure in response to an operation of a select lever (control lever) 20 provided in a vehicle compartment, or the like. A plurality of valves such as two shift valves (not shown) for switching the forward speed from the first speed to the fourth speed and a pressure regulator valve (not shown) for determining the line pressure are provided. The select lever 20 is
As is well known, the vehicle is slid in the front-rear direction to select a drive range such as a drive (D) range, a second speed range, a first speed range, a reverse (R) range, a neutral (N) range, or a parking (P) range. It has a structure.

Among the above valves, the shift valve is operated by driving the illustrated shift solenoids A and B. By combining the ON / OFF states of the shift solenoids A and B as shown in the following table, the first speed is established. To 4 speeds, the pressure regulator valve operates by controlling the duty ratio of the line pressure solenoid 13.

[0016]

[Table 1]

The A / T control unit 1 controls the driving of the shift solenoids A and B, the line pressure solenoid 13 and the other solenoids 11 and 12 to switch gear stages and reduce gear shift shocks associated with gear shifting. As is well known, the A / T control unit 1 basically performs a shift control such as a shift control in a state where the D range is selected by the select lever 20.
The optimum shift speed is determined based on the shift schedule shown in FIG. 3 according to the throttle opening obtained from the throttle sensor 4 and the vehicle speed obtained from the vehicle speed sensor 8, and the shift solenoids A and B are selected in accordance with this determination. ON / OFF
The automatic shift control for switching is performed. Further, when the select lever 20 is switched from the N range to the D range, the A / T control unit 1 temporarily sharply increases the line pressure and then rapidly lowers it to form a shelf pressure for precharging. (See FIG. 4), the precharge control for driving the line pressure solenoid 13 is performed.

Detection of the selected range of the select lever 20 is performed by the inhibitor switch 6. As shown in FIG. 5, the inhibitor switch 6 includes a P range switch PS, an R range switch RS, and an N range switch N.
S, D range switch DS, 2nd speed range switch 2S,
A first speed range switch 1S is provided, and a select lever 2
Depending on the position of 0, each switch PS, RS, NS, DS,
When either 2S or 1S is turned on (turned on), each switch PS, RS, NS, DS, 2S, 1S
Two switches are turned on at the same time between the areas where is turned on.
In order to prevent the switch from becoming N, a non-signal area in which neither switch is turned on is set. That is, as shown in the schematic diagram of FIG. 6, when the select lever 20 is arranged in the ON region of each range, each switch PS, RS, NS,
DS, 2S, 1S are turned on, and when placed in a no-signal area between them, all switches are turned off, and the inhibitor switch 6 does not output a detection signal.

The A / T control unit 1 performs range determination control for determining the selected position of the select lever 20 according to the ON / OFF state of the inhibitor switch 6. The range determination control will be described below with reference to the flowchart of FIG.

In step S1, the D range switch DS
Is determined to be ON, the process proceeds to step S2 if YES, the drive range is determined, and the process proceeds to step S3 if NO.

In step S3, the N range switch NS
Is determined to be ON, the process proceeds to step S4 if YES, the neutral range is determined, and the process proceeds to step S5 if NO.

In step S5, the R range switch RS
Is ON, the process proceeds to step S6 if YES, the reverse range is determined, and the process proceeds to step S7 if NO.

In step S7, the second speed range switch 2
It is determined whether or not S is ON, the process proceeds to step S8 if YES, it is determined to be the second speed range, and the process proceeds to step S9 if NO.

In step S9, it is determined whether or not the first speed range switch is ON, and if YES, the process proceeds to step S10 and 1
The speed range is determined, and if NO, the process proceeds to step S11.

In step S11, it is determined whether or not the no-signal state has continued for a predetermined time t (for example, t = second). If YES, the process proceeds to step S12 to determine the neutral range, and if NO, the process proceeds to step S13. Is judged to be the range immediately before.

Next, the operation of the embodiment will be described.

There are two cases in which the inhibitor switch 6 is in a non-signal state. One is the select lever 20
Is located in the no-signal region between each range, this condition is a short time event as it occurs when switching from one range to another. Therefore,
Since the no-signal time is within the predetermined time t, it is determined that the range is immediately before. For example, from 2nd speed range to D
When switching to the range, the inhibitor switch 6
The speed range switch 2S is switched from ON to OFF, and after a short period of no signal, the D range switch DS is switched from OFF to ON. At this time, the A / T control unit 1 is the second speed range switch. 2S is OFF
Even after that, the range is determined to be the second speed range even during the period of no signal, and the correct range is determined without determining the second speed range → N range → D range. As described above, in the no-signal region, the N range is not determined, so the precharge control is not performed and the shift shock is not deteriorated.

Another case where there is no signal is when the position of the range switch which is broken is selected.
In this case, since the no-signal time is equal to or longer than the predetermined time t, the range is determined to be N range.

Therefore, even if the line for transmitting the detection signal of the N range switch NS is broken, the N range is judged and the precharge control is performed when the N range is switched to the running range such as the D range. Is done.

As described above, in the shift control device for the automatic transmission according to the present embodiment, even if the N range switch NS is disconnected, it is determined that the N range is set and the precharge control is performed. However, when the select lever 20 is located in the no-signal area between the ON areas of the range switches during the operation, the range immediately before is not determined to be the N range, and thus the precharge is performed. The effect that the control is not performed and the shift shock does not worsen is obtained.

Although the embodiment has been described above, the specific structure is not limited to this embodiment, and the present invention includes a design change and the like within a range not departing from the gist of the present invention.

For example, in the embodiment, the example in which the precharge control is performed is shown, but the present invention can be applied to the case where the precharge control is not performed.

Further, in the embodiment, as the control lever, the select lever for operating the front and rear direction of the vehicle to select the range is shown. However, the lateral movement is added to the selection operation, and the gate is formed in a step shape. The present invention is also applicable to other levers such as a steering wheel mounted on a steering column and selectively operated in the vehicle width direction, and a gate type lever similar to the manual shift shown in the prior art.

[0034]

As described above, in the shift control device for an automatic transmission according to the present invention, when the shift control means has a state in which the range detection switch does not generate a detection signal, the state is predetermined. Within the time, the range is determined to be the range position immediately before, and when the state continues for a predetermined time or more, the range determination means for determining the neutral range position is provided, and thus the range with the range detection switch is detected. When a part is disconnected, it is judged that it is in the neutral range and the control is not stopped.Unnecessary to disconnect the control lever from one travel range to another while there is no signal. It is possible to obtain an effect that an accurate range determination can be performed without performing the neutral range determination corresponding to.

Further, in the apparatus according to claim 2, wherein the precharge control is performed at the time of switching from the neutral range to the running range, when the neutral switch is disconnected, the precharge control is accurately performed regardless of this disconnection. Therefore, while the shift shock can be reduced, the precharge control is not performed in the no-signal region between the traveling ranges, and the shift shock does not deteriorate.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to claims showing a shift control device for an automatic transmission according to the present invention.

FIG. 2 is a system diagram showing an overall configuration of a shift control device for an automatic transmission according to an embodiment of the present invention.

FIG. 3 is a shift characteristic diagram showing a shift schedule of the embodiment apparatus.

FIG. 4 is a line pressure characteristic diagram showing a change in line pressure due to precharge control of the embodiment apparatus.

FIG. 5 is a circuit diagram showing an inhibitor switch of the embodiment apparatus.

FIG. 6 is a schematic diagram showing an ON / OFF state of an inhibitor switch corresponding to a select lever operation of the embodiment apparatus.

FIG. 7 is a flowchart showing a flow of range determination control by an A / T control unit of the embodiment apparatus.

[Explanation of symbols]

Control lever b Range detection switch c Automatic transmission d shift control means e Range determination means

Continuation of front page (56) Reference JP-A-5-231529 (JP, A) JP-A-5-87233 (JP, A) JP-A-3-28571 (JP, A) JP-A-3-118354 (JP , A) Actually developed 62-147755 (JP, U) Actually developed 61-148722 (JP, U) Actually developed 3-117160 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB) (Name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (2)

(57) [Claims] 1. A control lever for performing a selection operation of a neutral range and a travel range, a range detection switch for detecting the neutral range and each travel range of the control lever, and an automatic gear shift based on the detection of the range detection switch. In a shift control device for an automatic transmission including shift control means for performing shift control of a machine and its related control, when a state in which the range detection switch does not generate a detection signal occurs in the shift control means, the state is A shift control device for an automatic transmission, characterized by comprising range determining means for determining that the current position is the immediately preceding range position when the time is less than a predetermined time, and for determining the neutral range when the state is at least a predetermined time. 2. The shift control means performs precharge control for temporarily increasing the hydraulic fluid pressure and then rapidly lowering the hydraulic fluid pressure to produce a shelf pressure for precharging when switching from the neutral range to the travel range. The shift control device for an automatic transmission according to claim 1, wherein: