JPS6343052A - Slip control device for automobile - Google Patents

Abstract

PURPOSE:To prevent as far as possible the excessive slipping of driving wheels in an automobile having an automatic transmission in its driving system, by providing a means for detecting the slip condition of driving wheels, and a speed-change characteristic changing means by which the output torque is decreased when slip is large. CONSTITUTION:A solenoid member 94 (for changing speed-change characteristics) is connected to a battery 101 via two switches 102 and 103 which are arranged in parallel each other. The switch 102 is to be operated by an operator, and the switch 103 is automatically ON/OFF controlled in response to the slip condition of driving wheels. Into a slip calculating circuit 104, signals from sensors 105 and 106 are entered. The calculating circuit 104 calculates a slip value SA in response to the revolution signals from the sansors 105, 106. Further, a reference circuit 107 outputs a signal corresponding to a reference slip value SB. These output values SA and SB are entered into a comparison circuit 108, and only when SA is greater than SB, the switch 103 is closed. Accordingly, the solenoid member 94 is magnetizedd or demagnetized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a slip control device for an automobile.

(Prior Art) It is desirable to prevent the slip of the drive wheels from becoming excessive in order to effectively obtain the propulsion force of the vehicle and to ensure safety.

For this reason, slip control devices have been proposed that reduce the torque generated by the engine or apply the brakes when the slip of the drive wheels becomes excessive (for example, Japanese Patent Application Laid-Open No. 16948/1983, Kaisho 60-566
(See Publication No. 62).

On the other hand, many automatic transmissions that are interposed in the drive system of an engine are capable of changing their speed change characteristics through manual operation. In other words, if the speed change characteristics are set using, for example, the accelerator opening and vehicle speed as parameters, for example, by switching between power mode and economy mode in two stages, when power mode is selected, the speed will be lower than when economy mode is selected. hand,
Some models are designed to shift gears at higher vehicle speeds for the same accelerator opening.

(Problem to be Solved by the Invention) By the way, the reason why the slip of the drive wheels becomes excessive is that the torque applied to the drive wheel is too large in the first place, so it is not possible to reduce this applied torque itself. If possible, this excessive slip can be prevented. One possible cause of this applied torque becoming too large is that the gear ratio is too large.

The present invention was made in consideration of the above circumstances, and
Provided is a slip control device for an automobile in which an automatic transmission is interposed in the drive system, and which prevents excessive slip of the drive wheels as much as possible by optimizing the shift characteristics of the automatic transmission. It's about doing.

(Means and operations for solving the problems) In order to achieve the above-mentioned object, the present invention has the following configuration.

That is, in an automobile in which an automatic transmission that changes speed based on a predetermined speed change characteristic is interposed in the drive system, there is provided a slip detecting means for detecting a slip state of the driving wheels, and a slip detecting means for detecting the slip state of the driving wheels; and a shift characteristic changing means for changing the shift characteristic so that the output torque from the automatic transmission becomes smaller when the slip of the automatic transmission is large.

With this configuration, when the slip of the drive wheels is large, the shift characteristics are changed so that the output torque of the automatic transmission becomes smaller, that is, the torque applied to the drive wheels is reduced, thereby preventing excessive slippage. Driving conditions in which slippage occurs are prevented as much as possible.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows the main parts of an example of a shift control device for an automatic transmission according to the present invention, together with an automatic transmission 10 to which this is applied and an engine E to which the automatic transmission IO is connected.

The automatic transmission 10 to which the example shown in No. 111 is applied,
This is a well-known in-vehicle device, and inside the casing,
A hydraulic torque converter 12 and a gear type transmission mechanism 14, which are shown in a simplified diagram, are built-in.

The input side of the fluid torque converter 12 is connected to the output shaft (not shown) of the engine E, and the output side thereof is connected to a transmission output shaft 16 via a gear type transmission mechanism 14. Gear type transmission mechanism 14 is configured such that its power transmission ratio can be switched into two stages by a clutch 22 and a brake 24 which are associated fluid actuators (two-speed forward transmission).In other words, the gear type transmission mechanism 14 is , both the clutch 22 and the brake 24,
Oil passage L4 from shift valve 60 of hydraulic mechanism 30 to be described later
When hydraulic pressure (line pressure) is supplied through clutch 2, the gear is switched from low gear to high gear.
When the hydraulic pressure is removed from both the brake 2 and the brake 24, the high gear is switched to the low gear. In the embodiment, the switching between the high speed gear and the low gear speed is performed based on a speed change characteristic using the throttle opening degree and the vehicle speed as parameters, as will be described later.

In the hydraulic mechanism 30 arranged to control the supply and removal of working hydraulic pressure to the clutch 22 and brake 24 described above, the working hydraulic pressure discharged from the oil pump 32 is regulated to a predetermined pressure by the regulator valve 34, and the line pressure is The oil is led out to the oil path L1. Line pressure is supplied to the throttle pressure generating valve 40, governor valve 50, and shift valve 60 through the oil passage 1.

The throttle pressure generating valve 40 includes a plug 43 that is pushed by a throttle cam 42 that rotates according to the opening degree of a throttle valve 28 that is provided in the intake passage 26 of the engine E and adjusts the amount of intake air, and this plug. 43 and a spool 41 that is pushed through a spring 44. The spool 41 is formed with a land portion 46 that opens and closes the boat 45 to which the oil passage 1 is connected, and a land portion 48 that opens and closes the drain boat 47. For this reason, the plug 43
When the spool 41 is pushed by the throttle cam 42, the spool 41 is displaced to the right in FIG. 1, changing the flow cross-sectional area between the oil passage L1 and the oil passage L2. As a result, the throttle pressure generating valve 40 outputs a signal according to the position of the spool 41.
Namely.

Throttle pressure corresponding to the opening degree of the throttle valve 28 is led to the oil passage L2. The throttle pressure led to the oil passage L2 is supplied to the right oil chamber 40a of the throttle pressure generating valve 40, and is also supplied to a pressure regulating means 70, which will be described later.

The governor valve 50 is provided in relation to the transmission output shaft 16 and has a spool 51 that also serves as a governor weight that is movable in the radial direction of the transmission output shaft 16.

The spool 51 is formed with a small diameter land portion 55 that opens and closes a boat 54 connected to an oil path, and a large diameter land portion 58 that opens and closes a drain boat 57. therefore,
In the governor valve 50, when the transmission output shaft 16 rotates, the spool 51 moves toward the outer circumference of the transmission output shaft 16 against the tensile force of the spring 53 in accordance with the centrifugal force caused by the rotation. As a result, the cross-sectional area of flow between the oil passage L1 and the oil passage L3 changes, the line pressure is regulated, and a governor pressure corresponding to the vehicle speed is derived from the governor valve 50 to the oil passage L3.

The shift valve 60 includes a small-diameter land portion 63 that opens and closes a boat 62 connected to an oil path L5 that branches from the oil path L1, a small-diameter land portion 65 that opens and closes a drain boat 64, and an oil path L6 that branches from the oil path L1. The spool 61 has a large diameter land portion 68 that opens and closes a boat 67 to which a boat 67 is connected. A biasing force of a spring 69 is applied to the spool 61 in the right direction in FIG.

The pressure regulating means 70 provided between the throttle pressure generating valve 40 and the shift valve 60 includes a control valve 75 and a reducing valve 80 to which throttle pressure is supplied from the control valve 75 through an oil path L8 or an oil path L9. have. control valve 75
When the spool 71 assumes the first operating position (the position shown by the solid line in FIG. 1), the oil passage L2 and the oil passage L8
When the spool 71 assumes the second operating position (the position shown by the dashed line in FIG. 1), the oil passage L
2 and the oil passage L8 are placed in a cutoff state, and the oil passage L2 and the oil passage L9 are placed in a communication state.

The reducing valve 80 has a spool 81 in which a land portion 83 for opening and closing the boat 82 connected to the oil passage L8 and a land portion 85 for opening and closing the boat 84 connected to the oil passage L9 are formed.

A biasing force of a spring 86 is applied to the spool 81 in the left direction in FIG.
Throttle pressure is applied to 1a through an oil passage L10 branching from oil passage L3.

A solenoid member 94 and a pressing rod 96 are attached to the control valve 75. When the solenoid member 94 is energized, the suppression rod 96 retracts as shown by the solid line in FIG. 1, causing the spool 71 of the control valve 75 to assume a first operating position. Further, when the solenoid member 94 is demagnetized, the suppressing rod 96 is projected by the built-in spring, thereby displacing the spool 71 of the control valve 75 in the right direction in FIG. 1 against the biasing force of the spring 73. Let me, second
to the operating position. And this solenoid member 9
The excitation and demagnetization control of No. 4, that is, the switching control of the speed change characteristics described later, is performed in accordance with the manual operation and the slip state of the drive wheels, as will be described in detail later.

In the configuration as described above, when the vehicle is in a running state (forward state), the throttle pressure generating valve 40 generates a throttle pressure according to the opening degree of the throttle valve 28 as a fluid signal pressure, and the governor valve 50 generates a throttle pressure according to the opening degree of the throttle valve 28. Depending on the situation, pressure is generated. Then, the throttle pressure is transmitted to the control valve 75 through the oil passage L2, and
Governor pressure is supplied to the right oil chamber 60b of the shift valve 60 through the oil passage L3.

Here, when the solenoid member 94 is demagnetized, the suppressing rod 96 is caused to protrude by a spring built in the solenoid member 94. As a result, the spool 71
is displaced to the right in Figure S1 against the biasing force of the spring 73, and assumes the second operating position as shown by the dashed line, and the oil passage L2 and oil passage L8 are brought into communication. , the oil passage L2 and the oil passage L9 are placed in a blocked state.

Therefore, in the reducing valve 80, the spool 81 receives throttle pressure on its left end surface 81a, and is displaced to the right as shown by the dashed line in FIG. and an open position where the boat 84 is opened by a predetermined area while blocking the boat 84, and a position where the right end face 81b receives pressure from the oil passage L7 and is displaced leftward from the open position as shown by the solid line in FIG. , and a closed position in which the boat 84 is closed. As a result, the left oil chamber 60a of the shift valve 60 has a third
In the figure, the vertical axis shows the oil pressure, and the horizontal axis shows the throttle opening, as shown by the broken line Ps', compared to the original throttle pressure (shown by the solid line Ps in Fig. 3). The reduced throttle pressure (hereinafter referred to as reduced throttle pressure) is supplied through the oil path L7.

Therefore, in this case, if the differential pressure between the reduced throttle pressure and the governor pressure acting on the spool 61 of the shift valve 60 exceeds a certain value, the spool 61 will move as shown in FIG.
is displaced to the left. As a result, the oil passage Ls and the oil passage 4 are communicated, line pressure is supplied to the clutch 22 and the brake 24, and the gear position in the gear type transmission mechanism 14 is switched from a low gear to a high gear. In this case, since the reduced throttle pressure is smaller than the throttle pressure, the gear change (upshift) based on the differential pressure between the throttle pressure and the governor pressure is shown by the broken line in Fig. 5. The first (economy mode) shifting characteristic follows the shifting line S1 where the shifting line is on the low vehicle speed side. In addition, in this case, when changing the gear from the high gear to the low gear, the spool 61 of the shift valve 60 is moved from the position shown in FIG. 4 to the first gear.
This is achieved by returning to the position shown in the figure, and the shift line at this time is shifted to a lower vehicle speed side than the shift line Sl (hysteresis between upshift and downshift).

On the other hand, when the solenoid member 94 is energized, the push rod 96 causes the lead-in pipe pool 71 to assume the first operating position. Therefore, the oil passage L2 and the oil passage L8 are brought into communication, and the oil passage L2 and the oil passage L9 are brought into a blocked state.

Therefore, in the reducing valve 80, the throttle pressure acting on the left end surface 81a of the spool 81 is
1[1, Ls and U are removed via the drain boat 77 of the control valve 75, and the spool 81 is in a state displaced to the left by the biasing force of the spring 86 (the state shown in FIG. 1). As a result, the oil passage L8 connected to the boat 82 and the oil passage L7 connected to the boat 89 are communicated with each other, and the throttle pressure is directly supplied to the left oil chamber 60a of the shift valve 60 without being reduced through the oil passage L7. Ru.

In such a case, the throttle pressure supplied to the shift valve 60 increases in accordance with the vehicle speed, as shown by the solid line Ps in FIG.

Therefore, when the differential pressure between the throttle pressure acting on the spool 61 and the pannier pressure exceeds a certain value, the spool 61 moves to the fourth position.
As shown in the figure, it is displaced to the left. As a result, the oil passage L5 and the oil passage 4 are communicated, line pressure is supplied to the clutch 22 and the brake 24, and the gear position in the gear type transmission mechanism 14 is switched from a low gear to a high gear.

Therefore, the gear change (upshift) based on the differential pressure between the throttle pressure and the governor pressure is performed as shown by the solid line in FIG. mode) is performed depending on the speed change characteristics. In addition, in this case, changing the gear position from a high gear position to a low gear position (downshifting) is the opposite of the above-mentioned upshifting.
This is achieved by returning the spool 61 of the shift valve 60 from the position shown in FIG. 4 to the position shown in FIG. It becomes something that has shifted (hysteresis between shift up and shift town).

Next, we will discuss an example of a control circuit for controlling the solenoid member 94, that is, switching the speed change characteristics.
This will be explained using figures.

First, the solenoid member 94 is connected to the battery 1 as a power source.
01, two switches 102,1 in series with each other
It is connected via 03.

Of these two switches, switch 102 is manually operated by the driver. Further, the switch 103 is dynamically controlled to open and close depending on the slip state of the drive wheels.

To explain the configuration of the part that controls the opening and closing of the switch 103, 104 in FIG. 6 is a slip value calculation circuit;
This arithmetic circuit 104 receives a signal from a sensor 105.10B. This sensor 105 detects the rotation speed of the driving wheels, and the sensor 105 detects the rotation speed (vehicle speed) of the driven wheels. Then, the arithmetic circuit 10
4 calculates a slip value (slip rate) SA determined by the following equation according to the rotational speed signals from both sensors IO5 and 106.

5A=1-driven wheel rotation speed/driving wheel rotation speed 107 in Fig. 6 is a reference circuit, and a predetermined reference slip value SH
Outputs a signal corresponding to

The output values SA and SB from both the circuits 104 and 107 are input to a comparison circuit 108. The comparison circuit 108 closes the switch 103 only when SA>SH (when the slip of the drive wheels is large) (the drive circuit for the switch 103 is not shown).

Depending on the opening and closing of both the switches 102 and 103, the solenoid member 94 is energized (power mode) or deactivated. a (economy mode), and both switches 102
．． The relationship between the opening/closing manner of 103 and the resulting mode is summarized in the vestibule.

As is clear from this table, even if the power mode is requested by manual operation (closing the switch 102) (as shown in Tables ■ and ■), the power mode is activated only when the slip of the drive wheels is small (■ mode), when the slip of the driving wheels is large, the switch 103 is opened, so the power mode is not set but the economy mode is set (mode of 2). It should be noted that when the economy mode is selected by manual operation, the economy mode is set regardless of whether the switch i03 is opened or closed (aspects (1) and (2) in Table 1).

Although the embodiments have been described above, the present invention is not limited thereto, and includes, for example, the following cases.

■There may be three or more types of speed change characteristics. In this case, when the drive wheel slip is large, the shift characteristics are changed from the current shift characteristics to a direction that reduces the output torque of the automatic transmission.
The speed change characteristics may be changed step by step, or the speed change characteristics may be changed all at once to the speed change characteristic that provides the smallest output torque.

■The automatic transmission may have three or more forward speeds.

■The speed change control of the automatic transmission may be electronically controlled.

0> The slip state of the driving wheels is directly detected by sensors 105 and 106, and the wiper is operating.
As the outside temperature is low and the drive wheel load is small,
When the drive wheel is in a situation where it is likely to slip, it may be assumed that the slip of the drive wheel is large (indirect detection - slip prediction 7!11).

<M) The slip state of the driving wheels may be identified by the magnitude of the coefficient of friction (for road surfaces) of the tires with respect to the road surface.

■It may not be possible to manually select the speed change characteristics. However, if the present invention is applied to this manual selection of transmission characteristics, it is advantageous in avoiding the danger of the driver erroneously selecting a transmission characteristic that causes excessive slip of the drive wheels. becomes.

(Effects of the Invention) As is clear from the above description, the present invention can avoid excessive slip of the drive wheels as much as possible by changing the shift characteristics of the automatic transmission.

In particular, many of the recent automatic transmissions have variable shift characteristics, which is advantageous in implementing existing automatic transmissions easily and at low cost without making major changes.

[Brief explanation of the drawing]

FIG. 1 is a shift hydraulic circuit diagram showing an embodiment of the present invention. Figures 2 and 4 are enlarged views of the main parts of Figure 1. FIG. 3 is a diagram showing the change characteristics of the throttle pressure for changing the speed change characteristics. Figure 5 is a transmission characteristic diagram. Figure 6 is a circuit diagram for changing the speed change characteristics. E: Engine 10: Automatic transmission 14: Transmission mechanism 16: Transmission output shaft 40: Throttle pressure generation valve 50: Governor valve 60: Shift valve 75: Control valve 80: Reducing valve 94: Solenoid member (for changing transmission characteristics) 102: Switch (mode selection Φ manual) 103: Switch (mode change/slip) 105: Sensor (driving wheel rotation speed) 106: Sensor (driven wheel rotation speed) Fig. 2 Fig. 3 Throttle distance

Claims (1)

[Claims] (1) In an automobile in which an automatic transmission that changes speed based on a predetermined speed change characteristic is interposed in the drive system, a slip detection means for detecting a slip state of a driving wheel; A slip control device for a motor vehicle, comprising: a shift characteristic changing means for changing the shift characteristic so that the output torque from the automatic transmission becomes smaller when wheel slip is large.