JPH0488256A - Automatic transmission - Google Patents

Abstract

PURPOSE:To prevent the sharp rise of the engine revolution when the gear position is at 4L by selecting the gear position from the shift pattern for high speed two/four wheel revolution to the shift pattern for low speed four wheel revolution, when it is judged that the gear position is at a low speed four wheel driving position and controlling a main speed change gear. CONSTITUTION:When a program starts, a TCM 7 reads in the output of a gear position switch 6, and checks from the read-in output whether the gear position of a T/F 3 is 4L or not, and in case of 4L, a shift pattern for 4L is selected, while in other case, a shift pattern for 2H/4H is selected. The shift pattern for 4L is set so that shift-up is performed in the lower speed region than that in case of the shift pattern for 2H/4H, for the equal throttle opening degree, and shift-up is performed during the lower resolution in comparison with the case of 2H/4H. Then, the TCM 7 sends a signal into a shift solenoid 5, in order to execute shift-up/down from the outputs of a throttle sensor 4 and a car speed sensor 8 on the basis of the selected shift pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic transmission, and more particularly to an automatic transmission equipped with a four-wheel drive sub-transmission.

[Prior Art] Traditionally, vehicle four-wheel drive transmissions have been designed to switch between two-wheel drive and four-wheel drive, or to switch the output of the main transmission between a high speed gear (reduction ratio -1) and a low speed gear (reduction ratio). 1) An auxiliary transmission is attached that switches between.

When the output of the main transmission is switched to a low gear in this auxiliary transmission, the output becomes larger by the reduction bone in the auxiliary transmission, so if the auxiliary transmission is switched to two-wheel drive in this state, two-wheel drive There were tremors that caused excessive loads to be applied to rotating shafts such as propeller shafts.

As a conventional example of preventing such an excessive load on the rotating shaft, there is a device disclosed in Japanese Patent Application Laid-Open No. 62-275830.

This device is equipped with two sets of hydraulic switching valves, and when the output of the main transmission is increased by switching to a low gear in the auxiliary transmission, this valve switching position is limited so that the four-wheel drive state (4L) is always maintained. This allows the increased output to be distributed not only to the two wheels but to all four wheels, thereby preventing excessive loads from being applied to any particular rotating shaft.

[Problem to be solved by the invention]

Here, if the weight of the vehicle is considered as an equivalent moment of inertia on the output shaft of the torque converter, this moment varies depending on the reduction ratio of the auxiliary transmission (particularly the gear ratio of the low speed gear).

That is, when the gear ratio (ratio of gear diameters) between high speed and low speed in the auxiliary transmission is 1:2, the moment in the low speed is 1/22 of that in the high speed.

This means that the load on the engine is significantly reduced, and therefore, when accelerating in the low gear (4L) of the four wheels, the engine rotational speed is lower than that in the high gear (4H), so the load on the engine is lower. It will be easier to rise.

To explain this phenomenon in more detail based on FIG. 5, conventionally, the engine speed for upshifting at each gear in the main transmission is high-speed two-wheel (2H), high-speed Both the four-wheel (4H) and low-speed four-wheel (4L) settings were the same.

However, as mentioned above, when the engine is at 4L, the load on the engine is smaller, so the rotation speed tends to increase, and especially when accelerating with the throttle fully open, the increase during the shift time lag (t in the figure) causes the red color shown by the two-dot chain line to increase. The engine may enter a zone or even enter a fuel cut state.

For this reason, there is a problem in that the vehicle is subject to rapid deceleration or jerky driving conditions.

This phenomenon was further exacerbated by improvements in response such as DOHC engines.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an automatic transmission device that can prevent the engine from increasing rapidly when the engine is in the 4L position.

[Means to solve the problem]

In order to solve the above problems, an automatic transmission according to the present invention includes a gear position detection means for a four-wheel drive sub-transmission, a high-speed two-wheel/four-wheel shift pattern for the main transmission, and the shift pattern. When it is determined that the gear position is the low-speed four-wheel drive position based on the memory storing the shift pattern for low-speed four-wheel drive set to a shift-up rotation speed lower than the shift-up rotation speed of the shift-up rotation speed and the output of the detection means, and means for controlling the main transmission by switching from a high-speed two-wheel/four-wheel shift pattern to a low-speed four-wheel shift pattern.

[For production]

In the present invention, the memory stores the shift-up rotational speed of the main transmission for normal 2H/4H shown by the dashed-dotted line in FIG.
/4 2 of the rotation speed of the shift amplifier for 4L, which is lower than that for H
Two rotation speeds are set.

When the control means detects that the gear position is 4 from the output of the gear position detection means provided in the auxiliary transmission, the control means detects that the gear position is 4.
The main transmission is controlled to perform a shift-up at a lower rotation speed than usual based on the L shift-up rotation speed.

Therefore, according to the present invention, even if full throttle acceleration is performed at 4L, a sudden increase in engine speed can be suppressed.

〔Example〕

Embodiments of the automatic transmission device according to the present invention will be described below.

The first part shows the configuration of one embodiment of the present invention,
1 is an engine, 2 is a main transmission (hereinafter abbreviated as Al1), 3 is a four-wheel drive sub-transmission connected to A/T2 (hereinafter abbreviated as T/F), and 4 is an intake of engine 1. A throttle sensor provided on the manifold detects the accelerator opening degree, 5 is a shift solenoid that shifts the gear position of the A/T 2, 6 is a gear position switch as means for detecting the gear position of the T/F 3, 7 is a throttle sensor 4 and a gear A TCH (Tran) serves as a control means that reads the output of the position switch 6 and outputs a control signal to the shift solenoid 5.
control module)
, and 8 is a vehicle speed sensor (or output shaft rotation speed sensor of A/T2).

FIG. 2 is a flowchart of a program stored and executed in the TCM 7 shown in FIG.
The operation of the configuration shown in FIG. 1 will be explained based on this diagram.

When this program starts, the TCM 7 first reads the output of the gear position switch 6 (step S in Figure 2).
l). Next, check whether the gear position of T/F3 is 4 from the read output (step S2), and if it is 4L, select the shift pattern for 4L shown in Figure 3b) (step S3), 4L. If not, 2 shown in the same figure (a)
H/4 Select the shift pattern for H (step S
4).

Now, to explain the shift pattern shown in Fig. 3, the shift pattern shown in Fig. 3 (a) is for 2H/4H, and is based on the shift-up rotation speed for 2H/4H shown by the dashed line in Fig. 4. (b)
The shift pattern is exclusive to the 4L, and is set based on the shift-up rotational speed for the 4L shown by the chain three-dot line in FIG.

As can be seen by comparing Figures (a) and 3), Figure (b)
The shift pattern for 4L is when the throttle opening is the same,
It is set to shift up in a lower speed range than the 2H/4H pattern shown in FIG. This indicates that the engine shifts and amps at lower revolutions than during 2H/4H.

Subsequently, the TCM 7 sends a signal to the shift solenoid 5 to execute up/down shifts based on the outputs of the slot sensor 4 and the vehicle speed sensor based on the shift pattern selected in step S3 or S4. (Same Step S5) [Effects of the Invention] As described above, the automatic transmission according to the present invention is configured to shift up based on the 4L shift pattern, which is set to a lower rotation speed than usual when in 4L. It is possible to prevent the engine rotation from rapidly increasing during acceleration, and as a result, the following unique effects can be obtained.

) The engine speed does not enter the red zone, so the driver does not feel anxious.

Seika) Can prevent sudden engine braking due to engine fuel cut.

ij) Due to the above, safe and smooth running can be ensured.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of an automatic transmission according to the present invention, FIG. 2 is a flowchart of a program executed in the present invention, and FIG. 3 is a main transmission executed in the present invention. FIG. 4 is a graph diagram explaining the principle of operation of the present invention. FIG. 5 is a graph diagram explaining the disadvantages of the operation of the conventional example. In Figure 1, 1 is the engine, 2 is the main transmission (A/T
), 3 is a sub-transmission (T/F), 4 is a throttle sensor, 5 is a shift solenoid, 6 is a gear position switch, and 7 is a TCM. In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A gear position detection means for a four-wheel drive sub-transmission, a high-speed two-wheel/four-wheel shift pattern for the main transmission, and a low-speed four-wheel shift pattern set to a shift-up rotation speed lower than the shift-up rotation speed of the shift pattern. If it is determined that the gear position is a low-speed four-wheel drive position based on the memory that stores the shift pattern for the wheels and the output of the detection means, the shift pattern for the low-speed four-wheels is determined from the shift pattern for the high-speed two-wheels and four-wheels. An automatic transmission device comprising: means for controlling the main transmission by switching to a pattern.