JPS6277228A - 2-wheel/4-wheel drive automatic shifting device - Google Patents

Abstract

PURPOSE:To make it possible to control an accurate drive shifting, by furnishing a device to compare the driving force and the driving force delivery limit, outputting 4-wheel-drive signal to a coupling device when the driving force is larger than the driving force delivery limit, and 2-wheel-drive signal when it is smaller. CONSTITUTION:A torque map of the driving system is stored beforehand at a torque map memory 5, while the driving force delivery limit value is stored beforehand in a driving force delivery limit setter 6. During running, the accelerator opening, the gear stage number, and a driving rotation number at the time are read out in a driving force arithmetic unit 4 to compute the driving force. Then the driving force value and the driving force delivery limit value are compared at a comparison and deciding unit 7, and, the 2-wheel-drive signal when the driving force value is smaller, and the 4-wheel-drive signal when it is larger, is output to a coupling device. Therefore, the 2-wheel/4-wheel drive shifting can be controlled accurately after detecting the torque condition of the car, and the engine driving force can be transmitted effectively.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic switching device for two-wheel drive or 74-wheel drive in a vehicle drive system, and particularly for two-wheel drive/four-wheel drive that can perform accurate automatic switching control. This invention relates to an automatic drive switching device.

[Conventional technology]

Generally, when comparing two-wheel drive and four-wheel drive, four-wheel drive grips the road surface with its four wheels, and therefore has a higher driving force transmission limit than two-wheel drive. In other words, when the engine driving force is large, such as when starting in a low gear and with a large accelerator opening, with two-wheel drive, the engine driving force cannot be completely transmitted to the road surface. In extreme cases, slipping may occur, but with four-wheel drive, such phenomena do not occur and the engine driving force can be used effectively.

[Problem that the invention seeks to solve]

Therefore, in a vehicle drive system that has a coupling mechanism that can switch between two-wheel drive and four-wheel drive, switching between two-wheel drive and four-wheel drive is performed taking into consideration the driving force limit and engine driving force. However, in the past, this switching was done manually, so the engine driving force was not used effectively.

In addition, recently, the engine accelerator opening, wiper operation/non-operation, and brake operation/non-operation are detected, and the combination of these detection signals automatically switches between two-wheel drive and four-wheel drive. However, such detection signals do not necessarily represent the torque state of the vehicle, and accurate control remains undesirable.

The present invention solves the above-mentioned problems, and in particular, a two-wheel drive system that can accurately control automatic switching between two-wheel drive and four-wheel drive by pinking up parameters representative of the actual engine output state. It is an object of the present invention to provide a 74-wheel drive automatic switching device.

[Means for solving problems]

To this end, the two-wheel drive/four-wheel drive automatic switching device of the present invention includes a storage means that stores in advance a torque map determined by the engine accelerator opening, the number of gears, and the rotation speed of the drive device, the engine accelerator opening when driving, Calculating means for detecting the number of gears and the rotational speed of the drive device and comparing it with a torque map to calculate the driving force at that point in time; a driving force transmission limit setting means for setting a driving force transmission limit; and the driving force and driving force transmission. The present invention is characterized by comprising a means for outputting a four-wheel drive signal to the coupling mechanism when the driving force is larger than the limit, and a two-wheel drive signal when the driving force is smaller to the coupling mechanism.

[Action and effect of invention]

The two-wheel drive/four-wheel drive automatic switching device of the present invention compares the driving force with the driving force transmission limit, and when the driving force is greater, outputs a four-wheel drive signal, and when it is smaller, outputs a two-wheel drive signal. Since it is output to the coupling mechanism, switching control between two-wheel drive and four-wheel drive can be performed particularly accurately, and engine driving force can be transmitted effectively.

〔Example〕

Examples will be described below with reference to the drawings.

Figure 1 shows one of the two-wheel drive/four-wheel drive automatic switching devices of the present invention.
Diagrams showing the configuration of the embodiment, FIG. 2(A) is a torque map of a vehicle with a manual transmission, FIG. 2(B) is a torque map of a vehicle with an automatic transmission, and FIG. 3 is an example of a driver selection button in the driving force transmission limit setting means. FIG.

In FIG. 1, 1 is an accelerator opening detection section, 2 is a gear stage detection section, 3 is a rotation speed configuration section, 4 is a driving force calculation section, 5 is a torque map storage section, 6 is a driving force transmission limit setting section, 7 indicates a comparison/judgment section.

The torque map of the drive device is stored in the torque map storage unit 5 in advance.
As shown in Figures (A) and (B), it can be drawn by considering the accelerator opening, the number of gear stages (L speed, 2nd speed, etc.), and the drive device rotation speed as variables. Figure 2 depicts the case where the accelerator opening is 100% (at full throttle), but since the torque level also changes as the accelerator opening changes, it is possible to obtain a torque map that corresponds to each accelerator opening. becomes.

Further, the driving force transmission limit setting section 6 may store a fixed value in advance as the driving force transmission limit value, or the driver may select and set a limit value from among a plurality of values according to the situation. Make it. Here, as an example of when the driver is reluctant, considering that the driving force limit value changes depending on the road resistance, it is possible to select a button according to the road surface condition due to weather as shown in Figure 3. good.

The torque map and driving force limit value as shown above are set in the setting section t.
q, during actual driving, the driving force calculation unit 4 calculates the accelerator opening, the number of gears, and the driving rotation speed (engine rotation speed, transmission input or output rotation speed) at each point in time.
These detected values are compared with the torque map to calculate the driving force at that point in time. Then, the calculated driving force value is sent to the comparison and determination section 7.

On the other hand, the comparison/judgment unit 7 compares the driving force value and the driving force transmission limit value, and if the driving force value is smaller, the two-wheel drive signal is changed to
If it is larger, a four-wheel drive signal is output. The compling mechanism is controlled by this output signal. Therefore, if the compulsory mechanism switches between two-wheel drive and four-wheel drive by operating/non-operating, the two-wheel drive signal and the four-wheel drive signal are inverted signals, that is, whether or not it is two-wheel drive. Alternatively, one signal indicating whether the vehicle is in four-wheel drive or not is sufficient.

In addition, when detecting the engine rotation speed in the rotation speed detection section 3, the torque map for the engine rotation speed is
Further, when detecting the input rotation speed or output rotation speed of the transmission, it is sufficient to store a torque map for the manual rotation speed or output rotation speed of the transmission.

Therefore, in the above example, the engine rotation speed is used as the rotation speed of the drive device, but even if you use the input rotation speed or output rotation speed of the transmission instead, if you have a unique torque map as well, By detecting the accelerator opening, the number of gears, and the number of rotations of the drive device during driving, the driving force of the vehicle at that point in time can be accurately detected from comparison with the torque map.

Then, as described above, the driving force value is compared with the driving force limit value of two-wheel drive, and if the driving force value exceeds the limit value, four-wheel drive may be adopted.

As is clear from the above description, the present invention can be modified in various ways and is not limited to the above embodiments.

According to the present invention, since the torque state of the vehicle is accurately detected and the switching between 2-wheel drive and 4-wheel drive is automatically performed, engine driving force is effectively transmitted, resulting in excellent economical effects. Not only this, but also the driving sensation, driving stability, etc. can be maintained in good condition.

[Brief explanation of drawings]

Figure 1 shows one of the two-wheel drive/four-wheel drive automatic switching devices of the present invention.
2(A) is a torque map of a vehicle with a manual transmission, FIG. 2(B) is a torque map of a vehicle with an automatic transmission, and FIG. 3 is an example of a driver selection button in the driving force limit setting means. FIG. 1...Accelerator opening detection section, 2...Gear stage detection section,
3... Rotation speed detection unit, 4... Driving force calculation unit, 5...
- Torque map storage section, 6... Driving force transmission limit setting section, 7... Comparison determination section. Figure 1 Figure 3

Claims (6)

[Claims] (1) In a two-wheel drive/four-wheel drive automatic switching device equipped with a coupling mechanism for switching between two-wheel drive and four-wheel drive, it is determined by the engine accelerator opening, the number of gears, and the rotation speed of the drive device. A storage means that stores a torque map in advance; a driving force that detects the accelerator opening of the engine, the number of gears, and the rotation speed of the drive device during driving, and calculates the driving force at that point in time by comparing it with the torque map of the storage means; a calculation means, a driving force limit setting means for setting a driving force limit, a driving force limit setting means that compares the driving force with the driving force limit, and when the driving force is larger, a four-wheel drive signal is sent, and when it is smaller, a two-wheel drive signal is sent. A two-wheel drive/four-wheel drive automatic switching device comprising: means for outputting to the coupling mechanism. (2) Two-wheel drive according to claim 1, wherein the rotational speed of the disturbance device is the engine rotational speed.
Wheel drive automatic switching device. (3) The two-wheel drive/four-wheel drive automatic switching device according to claim 1, wherein the rotation speed of the drive device is the transmission input rotation speed. (4) The two-wheel drive/four-wheel drive automatic switching device according to claim 1, wherein the rotation speed of the drive device is the transmission output rotation speed. (5) Two-wheel drive/four-wheel drive according to claims 2 to 4, wherein the driving force limit setting means is a storage means for storing a predetermined driving force limit value. Automatic switching device. (6) The two-wheel drive/four-wheel drive automatic according to claims 2 to 4, wherein the driving force limit setting means is one in which the driver supports the driving force limit value with a switch. Switching device.