JP2817370B2 - Transmission control device for automatic transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling a shift of an automatic transmission connected to an engine having a constant speed traveling means.

2. Description of the Related Art This type of engine is configured to maintain an actual vehicle speed at a set vehicle speed by controlling a throttle opening based on a set vehicle speed and a detected vehicle speed. In addition, in vehicles equipped with an automatic transmission, in general, constant speed traveling control of the engine and shift control of the automatic transmission are not particularly positively associated with each other. This is performed according to the vehicle speed and the throttle opening as in the case of the vehicle. Therefore, for example, if the vehicle speed does not increase even if the throttle opening increases due to large running resistance, the automatic transmission performs a downshift according to the shift diagram, and as a result, the driving force increases and the vehicle speed increases. Then, an upshift is performed. That is, if the driving force suitable for the running resistance at the set vehicle speed is about the middle of the driving force obtained at the two shift speeds, the above-described downshift and upshift will occur repeatedly. If the downshift and the upshift are repeated frequently, the shift shock becomes large and the riding comfort deteriorates, and if the vehicle is constantly driven at a low speed, the engine speed increases and the fuel consumption and noise deteriorate. .

As a device for controlling an automatic transmission connected to an engine having such a constant speed traveling means, a device disclosed in Japanese Patent Application Laid-Open
Japanese Patent Application Laid-Open No. 208208/1990 describes an apparatus for changing an upshift line in a shift diagram defining a shift point of an automatic transmission to a high speed side and changing a downshift line to a low speed side during constant speed traveling. According to this device, the range of the vehicle speed covered by the predetermined shift speed is expanded, so that the shift is less likely to occur, and a so-called busy shift in which the shift is repeatedly performed between the two shift speeds is prevented.

Problems to be Solved by the Invention In the above-mentioned conventional apparatus, if the vehicle speed does not decrease significantly or the throttle opening does not increase significantly, no downshift occurs, and if the vehicle speed does not increase significantly, If the opening is not considerably small, no upshift occurs, so that a busy shift can be prevented.However, since the shift line is set to obtain the originally required driving force, the shift line is set to the lower speed side or If the speed is changed to the high-speed side, the required driving force cannot be obtained, and the power performance is reduced, or the ride comfort is deteriorated. That is, in the above-described conventional device, even when the driving speed is insufficient due to the running resistance and the vehicle speed decreases, a downshift is unlikely to occur. It becomes a vehicle with the impression that power performance is bad when it grows large. If the vehicle speed increases after downshifting, the set vehicle speed is maintained by operating the accelerator. However, when the upshift point becomes high, the engine speed is maintained at a high state, and the running at the high engine speed is forced, and the fuel efficiency is deteriorated.

The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a shift control method capable of preventing a frequent shift during constant speed traveling control and obtaining a sufficient driving force at the same time.

Means for Solving the Problems In the conventional device described above, shifting is hardly caused at the expense of inadequate driving force to be obtained, but the present invention contradicts this problem. By adapting the driving force to the resistance as much as possible, it is difficult to cause a shift. That is, according to the present invention, in a shift control device for an automatic transmission connected to an engine having a constant speed traveling means for maintaining a vehicle speed at a set vehicle speed, the constant speed traveling means is operated to perform constant speed traveling. Means for detecting the vehicle speed, and when it is detected that the vehicle is traveling at a constant speed, the number of gears is increased by increasing the number of gears compared to when the vehicle is not traveling at a constant speed. Means for setting a plurality of gears in which the width of the gear ratio between the gears becomes narrower.

In the device according to the present invention, when the constant speed traveling control is performed by operating the constant speed traveling means, the number of speed stages set by the automatic transmission is increased, and the interval (difference) between the speed ratios of the adjacent speed stages is increased. Or the ratio), that is, the width of the gear ratio becomes narrower, and a gear position capable of obtaining a more appropriate driving force with respect to the running resistance at the set vehicle speed is selected. Therefore, the vehicle speed does not significantly decrease or increase,
Frequent shifts do not occur, and quiet and fuel-efficient traveling becomes possible.

EXAMPLE Next, an apparatus of the present invention will be described based on an example.

An example of the device of the present invention is shown in a flowchart in FIG. 1. The automatic transmission targeted by this device is connected to an engine capable of constant-speed running control and has a plurality of types of engagement / disengagement patterns. Can set a predetermined gear position. FIG. 2 is a block diagram showing an example. That is, the automatic transmission A is connected to the engine E via the torque converter T, and the transmission control device 10 receives the throttle opening θ, the vehicle speed V, the brake signal, the coolant temperature, the pattern select signal, and other signals. Then, based on such information, a gear position to be set and an engagement / disengagement pattern for setting the gear position are selected and a signal is output to the hydraulic control device C. Further, the shift control device 10 is connected to the engine control device 11. The engine control device 11 controls the throttle valve with a predetermined actuator (not shown) so as to maintain the set vehicle speed, and that the constant speed traveling control is performed and not performed. Is output to the transmission control device 10.

The above-mentioned automatic transmission A is provided with a gear train having a plurality of types of engagement / disengagement patterns for setting a predetermined gear position. An example of the gear train is shown in FIG. The example shown here is mainly composed of three sets of single pinion type planetary gear mechanisms 1, 2, and 3, and the respective elements of the planetary gear mechanisms 1, 2, and 3 are connected as follows. That is, the carrier 1C of the first planetary gear mechanism 1 and the ring gear 3R of the third planetary gear mechanism 3 are connected so as to rotate integrally, and the ring gear 2R of the second planetary gear mechanism 2 and the third planetary gear mechanism 3 And the carrier 3C are connected so as to rotate integrally. The sun gear 1S of the first planetary gear mechanism 1 is connected to the carrier 2C of the second planetary gear mechanism 2 via the second clutch means K2, while the sun gear 1S of the second planetary gear mechanism 2 is connected via the fourth clutch means K4. The carrier 2C of the second planetary gear mechanism 2 is further connected to the sun gear 3S of the third planetary gear mechanism 3 so as to rotate integrally therewith.

In addition, as a connection structure of the above-described components, a connection structure employed in a general automatic transmission such as a hollow shaft, a solid shaft, or an appropriate connecting drum can be employed.

The input shaft 4 is connected to the engine E via a power transmission means (not shown) such as a torque converter and a fluid coupling, and the input shaft 4 and a ring gear of the first planetary gear mechanism 1 are connected.
1R, a first clutch means K1 for selectively connecting the two is provided, and between the input shaft 4 and the sun gear 1S of the first planetary gear mechanism 1, the two are selectively connected. Third clutch means K3 is provided.

In practical use, there is a restriction on the arrangement of the components, so that an appropriate intermediate member such as a connecting drum can be interposed as a connecting member for the clutch means K1, K2, K3, K4.

The second planetary gear mechanism 2 serves as brake means for preventing the rotation of the rotating members in the planetary gear mechanisms 1, 2, and 3 described above.
A second brake means B2 for selectively blocking the rotation of the carrier 2C and a third brake means B3 for selectively blocking the rotation of the sun gear 2S of the second planetary gear mechanism 2 are provided.
These braking means may be a one-way clutch provided between a transmission case (hereinafter simply referred to as a case) 6 and a band brake arranged in parallel with the one-way clutch, in addition to the multi-plate structure. , Or in combination. In practical use, a proper connecting member can be interposed between the brake means B2, B3 and each element to be fixed by the brake means B2, B3 or the case 6. .

An output shaft 5 for transmitting rotation to a propeller shaft and a counter gear (not shown) is connected to a ring gear 2R of the second planetary gear mechanism 2 and a carrier 3C of the third planetary gear mechanism 3 connected to each other. ing.

In the automatic transmission A described above, five forward speeds and one reverse speed are set as main shift speeds, and a so-called 2.5th intermediate speed is added between the second forward speed and the third forward speed. 3rd and 4th
It is possible to set eight forward speeds and one reverse speed by adding two intermediate speeds, so-called 3.2th and 3.5th speeds, between the speeds. It is as shown in Table 1. In Table 1, ○ indicates that they are engaged, blanks indicate that they are released, and * indicates that they may be engaged. The gear ratios of the gears shown in Table 1 are the gear ratios (ratio between the number of teeth of the sun gear and the number of teeth of the ring gear) of each of the planetary gear mechanisms 1, 2, and 3 as ρ1 = 0.450, ρ2 = ρ
This is the value when 3 = 0.405.

An example of control by the control device of the present invention for the automatic transmission A having the above-described gear train is as shown in the flowchart of FIG. 1. First, in step 1, the throttle opening θ, the vehicle speed V, and the constant speed traveling The running conditions such as presence / absence of control (auto-drive control), a pattern select signal, and cooling water temperature are read. This can be performed by the shift control device 10 described above, and then it is determined from the read data whether or not the constant-speed running control is being performed, that is, the auto-tribe operation is determined (step 2). If the result of the determination is "No", the process proceeds to step 3 where a gear sequence of five forward speeds and one reverse speed is set, and a predetermined gear speed selected from these gear speeds based on running conditions is selected. Shift to.
The five forward speeds selected here are the first speed, the second speed, the third speed, the fourth speed, and the fifth speed shown in Table 1, and the speed ratios of these speed stages are equal ratios. The relationship is close to a series, and its width (ratio between variable ratios) is about “1.5” to “1.4”.

Also, if the cruise control is performed and the result of the determination in step 2 is “YES”, the flow proceeds to step 4 to set eight forward gears including all forward gears shown in Table 1.
The gear is shifted to a predetermined gear selected from these gears based on the running conditions. Therefore, in this case, the first
As is clear from the table, the width between the second speed and the second speed is about "1.3", the width between the third speed and the third speed is about "1.1", and The width between the third speed and the 3.5th speed is about "1.2", and the width between the third speed and the fourth speed is about "1.1", which is smaller than the case where the constant speed traveling control is not performed. Thus, the width of the gear ratio is narrow, and more various driving forces can be obtained.

Therefore, for example, if the driving force obtained at the third speed is too large for the set vehicle speed and the driving force obtained at the fourth speed is insufficient, the 3.2th or 3.5th speed, which is an intermediate speed between them, is selected. Since the driving force obtained at that gear is the driving force suitable for the running resistance at that time with respect to the set vehicle speed, slight excess or deficiency of the driving force is dealt with by fine adjustment of the throttle opening. Can maintain the set speed. As a result, since there is no shift caused by a decrease in the driving force or a significant change in the vehicle speed caused by the driving force, a so-called busy shift can be prevented and a sufficient driving force can be obtained.

Note that when the constant speed traveling control is not performed, the width of the gear ratio increases. However, if the gearshift occurs frequently or the driving force is insufficient, the vehicle speed is artificially adjusted, so the vehicle is busy. There is almost no shift or lack of driving power. In addition, since the shift according to the shift speed with a narrow gear ratio width is not performed when the vehicle speed is artificially adjusted, every time the accelerator pedal is slightly adjusted,
A busy shift such as a shift can be prevented.

In the above embodiment, the automatic transmission having the gear train shown in FIG. 3 has been described as an example. However, the control device of the present invention is connected to an engine capable of performing constant-speed running control. Automatic transmission having a gear train capable of selecting a shift between gears having a wide gear ratio width and a gear shift between gears having a narrow gear ratio width. As an example of an automatic transmission equipped with this kind of gear train, one of the friction engagement means shown in FIG. 3 including a one-way clutch,
Japanese Patent Application No. 1-185151, Japanese Patent Application No. 1-185151 already proposed by the present applicant.
-185152, Japanese Patent Application No. 1-186999, Japanese Patent Application No. 1-186999
And Japanese Patent Application No. 1-205478 and Japanese Patent Application No. 280957/1990, and the structures described in the drawings.

Effect of the Invention As is clear from the above description, according to the method of the control device, at the time of constant speed traveling control in which the vehicle speed during traveling is controlled to be maintained at a constant vehicle speed, the traveling resistance at the set vehicle speed is reduced. Since the gear is set to a speed at which a more appropriate driving force can be obtained, it is possible to avoid shortage of the driving force, fluctuation of the vehicle speed and frequent shifts based on the shortage.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining a control example by the control device of the present invention, FIG. 2 is a block diagram showing a basic configuration of an automatic transmission to which the present invention is applied, and FIG. 3 is an example of the gear train. It is a skeleton diagram shown. 1, 2, 3 planetary gear mechanism, 4 input shaft, 5 output shaft, 10 transmission control device, 11 engine control device, A automatic transmission, C hydraulic control device , E ...
…engine.

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Claims (1)

(57) [Claims] 1. A shift control device for an automatic transmission connected to an engine having a constant speed traveling means for maintaining a vehicle speed at a set vehicle speed, wherein the constant speed traveling means is operated to perform constant speed traveling. Means for detecting the vehicle speed, and when it is detected that the vehicle is traveling at a constant speed, the number of gears is increased by increasing the number of gears compared to when the vehicle is not traveling at a constant speed. Means for setting a plurality of gears in which the width of the gear ratio between the gears becomes narrower.