JPS6243325A - Brake controller for four-wheel drive car - Google Patents

Abstract

PURPOSE:To reduce the influence to the traveling performance accompanied by the releasing switching by installing a means for detecting the operation of an antiskid brake system (ABS) and releasing the front/rear-wheel direct- connection state by the detection signal. CONSTITUTION:A clutch 45 for 2-4 wheel switching is operated by a direct- connection releasing modulator 13, and a controller 14 controls the slip rate of a wheels on the basis of the signal of a speed sensor 56a, etc. When an operation signal 11 is input into a direct-connection releasing controller 12 in brake application, and an ABS operation signal is input from the controller 14, switching to 2-wheel drive by the modulator 13 is carried out simultaneously with the start of the operation of the ABS. Therefore, the influence to the traveling performance of a car due to the switching can be reduced by carrying out the releasing switching of the front/rear-wheel direct-connection state only when ABS control is started.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is a four-wheel drive vehicle that can drive both front and rear wheels, and an anti-skid brake system (
The present invention relates to an automobile having ABS (hereinafter also referred to as ABS).

(Prior art) When a brake is operated while a car is running, the brake force reaches its maximum when the wheel slip rate is around 20%. Anti-skid braking systems, which prevent the wheels from locking by preventing the wheel slip rate from becoming too large and maintain the braking force close to maximum, have long been known and have been put to practical use in two-wheel drive vehicles. . To give one example, JP-A-57-774
As disclosed in Japanese Patent No. 7, there is a two-wheel drive vehicle in which the brake oil pressure is controlled in accordance with the deceleration of the wheel speed to prevent the wheels from locking during braking. However, a four-wheel drive vehicle using ABS has not yet been realized.

This is because the ABS operates by detecting the slip rate of the wheels, so when measuring the speed of the slipping wheel and the actual vehicle speed, in the fourth row, the rotation of each of the four wheels is detected, and the rotation of the slipping wheel is detected. This is because the slip rate is calculated using the actual vehicle speed calculated from the speed of the wheels that are not slipping, and the ABS of this method is 4.
This is because when incorporated into a wheel drive vehicle, all four wheels are mechanically connected, so all four wheels slip at the same time, making it difficult to calculate the actual vehicle speed. Although it is technically possible to detect the actual vehicle speed using a sensor such as a sonic detector, there are problems with practical implementation at this stage due to cost and other reasons.

For this reason, 4-wheel drive vehicles are equipped with ABS, which is conventionally used in 2-wheel drive vehicles.
It is conceivable to switch from four-wheel drive to two-wheel drive when the S III control is performed, that is, when the brakes are applied. In this case, there are many ways to detect brake operation, such as detecting 0N-OFF of the brake pedal switch and brake fluid pressure switch, but when these switches are turned on, 4-wheel drive is always activated. If the brake pedal were to be switched from 1 to 2 wheel drive, the switch from 2 to 4 wheel drive would occur frequently when the brake pedal was depressed lightly or repeatedly. Unfavorable from a performance standpoint.

(Object of the Invention) In view of the above-mentioned circumstances, the present invention provides a brake control device for 4-wheel drive vehicles, which allows 4-wheel drive vehicles to be equipped with ABS, which has conventionally been used in 2-wheel drive vehicles. This purpose is achieved by switching from four-wheel drive to two-wheel drive when the brakes are applied.
It is an object of the present invention to provide a brake control device that can reduce the effect of switching on driving performance by causing switching to be performed only when necessary.

(Structure of the Invention) The brake control device of the present invention includes a four-wheel drive device that drives both front and rear wheels, and an anti-skid brake system, and detects the anti-skid brake system (
The present invention is characterized in that when the operation of the ABS (ABS) is detected, the direct connection between the front and rear wheel drive systems is released by a release means, and the ABS is activated.

(Embodiments) Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a drive system and an AB S llll tll system of a four-wheel drive vehicle equipped with a brake control device of the present invention. After the driving force of the engine 9 is shifted in the transmission 10, the driving force is transferred to the transfer 20.
transmitted to. The transfer 20 is provided with a 2-4 wheel switching clutch 45, and when the 2-wheel drive is selected by the 2-4 wheel switching clutch 45, the engine 9 transmitted to the transfer 20 via the transmission 10 is The driving force of
a.

6b to the rear wheels 4a, 4b.
Drive b. At this time, no power is transmitted to the front propeller shaft 7, and the front wheels 1a and 1b are in a state where they can freely rotate.

On the other hand, when four-wheel drive is selected by the 2-4 wheel switching clutch 45, the 2-4 wheel switching clutch 45 operates to directly connect the front propeller shaft 7 to the input shaft of the transfer 20. Thereby, the driving force of the engine 9 transmitted to the transfer 20 is transmitted to the front and rear propeller shafts 7.
The transmission is divided into 8 parts, and the front wheel and rear wheel differential 2
．． 5 and front and rear axle shafts 3a, 3b.

6a, 6b to the front wheels 1a, 1b and the rear wheels 4a, 4b, respectively.
, 4b are both driven.

As described above, the 2-wheel drive state or the 4-wheel drive state can be selected, and this 2-4 wheel switching clutch 4
5 is performed by a direct connection release modulator 13, and the operation control of this direct connection release modulator 13 is performed by a direct connection release controller 12.

This car also has ABS installed. This ABS has a speed sensor 56 that detects the rotational speed of each wheel.
AB based on signals from a, 56b, 57a, 57b
The S controller 14 calculates the slip rate of each wheel, outputs an activation signal to the ABS modulator 15, adjusts the brake pressure of each wheel, and controls the slip rate so that it does not exceed a predetermined value. However, when four-wheel drive is selected by the 2-4 wheel switching clutch 45, each wheel is in a directly coupled state, making calculation of the slip ratio inaccurate. Therefore, in this automobile, a brake operation switch is provided, and when the brake is operated, the operation signal 11 is input to the direct connection release controller 12, and the A88 controller 14 is connected to the line 14a.
An ABS activation signal is inputted via the .

Therefore, when the brake is actuated and operation No. 13 11 is input to the direct connection release controller 12, and when the ABS operation signal is input from the ABS controller 14,
B S ilJ 1ull has started,
At this time, the ABS controller 14 and the ABS modulator 15 start operating the ABS, and at the same time, the direct link release controller 12 operates the direct link release modulator 13 so that the vehicle can be switched to two-wheel drive. Note that the 88 activation signal is a signal that notifies the start of AB SIL+ control. For example, when the wheel rotational deceleration during brake activation reaches a certain value, this signal is issued to start ABS control. It has become.

As a result, even if the brake pedal is depressed, it is possible to switch to two-wheel drive and perform AB SILJ lft only when the ABS operation starts, so that the so-called "small brake pedal" It is possible to prevent unnecessary switching from 2 to 4 wheels in the case of "depressing the pedal" or repeatedly depressing the pedal, and to reduce the influence on driving performance.

The brake operating state is detected by detecting the operation of the brake pedal, detecting whether the brake pedal switch is ON or OFF, or detecting whether the brake fluid pressure switch is ON or OFF.

Next, the control contents of the direct connection release controller 12/3 and the A88 controller 14 will be explained with reference to the flowchart shown in FIG.

This flow starting from step S1 determines whether or not the 2-4 wheel switching clutch 45 is operated in step S2, that is, this clutch 45 is operated and the front and rear propeller shafts 7
．． 8 is directly connected to detect whether or not the vehicle is in four-wheel drive mode. When the vehicle is not directly connected, that is, when the vehicle is in a two-wheel drive state, the process advances to step S3 and this flow ends. However, if the brakes are activated at this time, the ABS is immediately activated.

When directly connected, that is, when in four-wheel drive mode, step S
Step 4 proceeds to step S5, where the brake operating state detection means 11 detects whether the brake switch is ON or not. If it is OFF, the process proceeds to step S5 and the flow is ended as it is. When the brake switch is ON, proceed to step S6 and AB
Determine whether the S operation signal is ON or not, and if it is OFF, turn it ON.
Wait for the signal to arrive, and if it is ON, proceed to step S7 and output a release signal from the direct connection release controller 12 to the direct connection release modulator 13, and the 2-4 wheel FJ) exchange clutch 4
5 to switch to two-wheel drive (step S8)
.

Also, when the ABS operation signal is ON, step S
The process also proceeds from step S9 to step S9, where ABS control is performed. A
BS includes speed sensors 56a, 56b, 57a for each wheel,
Calculate the wheel slip rate from the speed signal from 57b,
The ABS is activated when this slip ratio exceeds a predetermined value, and the ABS is activated in step S9.
The S modulator 15 lowers the brake fluid pressure acting on wheels with a high slip ratio to keep the slip ratio at an appropriate value so that the braking force is always maximized. At this time, since the direct connection of the front wheels by the four-wheel drive device has been released in steps S7 and S8, the slip ratio can be calculated accurately and the ABS control can also be performed correctly. Next, when it is detected that the slip rate has decreased and the ABS operation signal has turned OFF (step 510), the process proceeds to step S11, where it is determined whether the brake switch is OFF, and when it is ON, the process proceeds to step S12 again. Return to BS operation.

When the brake switch is turned OFF, steps 812~
Proceeding to S13, the direct coupling signal is turned OFF, and the front and rear propeller shafts 7.8 are again directly coupled by the 2-4 wheel switching clutch 45, returning to four-wheel drive, and then proceeding to step S14, where this flow ends.

Next, the structure of the transfer 20 is shown in FIG.
- Explain four-wheel drive switching.

The input shaft 21 and the output shaft 22 of this transfer 20 are arranged coaxially and separately, and the input shaft 21 is provided with a low-speed clutch 23 and a high-speed clutch 24, and the output shaft of the high-speed clutch 24 is It is formed on the inner surface of an input gear 25 connected to the inner shaft end of the output shaft 22, and when this high-speed clutch 24 is turned on, the output of the input shaft 21 is directly transmitted to the output shaft 22.

An output gear 26 is formed on the output side of the aforementioned low-speed clutch 23 and is supported on the input shaft 21 via a bearing, and this output gear 26 is connected to the input side 27 of the reduction gear 27.28.
The output side 28 thereof meshes with the input gear 25 described above, and the reduction gears 27 and 28 are rotatably supported by a support shaft 30 installed in the case 29 via bearings.

The above-mentioned output shaft 22 is equipped with a clutch 45 for switching between 2-4 wheel drive.
An output block 31 for front drive is formed on the output side of the clutch 45, and the output shaft 2
It is supported on the second shaft via a bearing. In the lower part of the case 29 mentioned above, there is an input sprocket 3 for front drive.
2 is pivotally supported via a bearing, and the above-mentioned output block block 3
A chain 33 is strung between 1 and 1. According to the above drive system, when the low speed clutch 23 is turned on,
The output shaft 22 is driven via the output gear 26, reduction gears 27, 28, and input gear 25, and the high-speed clutch 24 is turned on.
When operated, the output shaft 22 is directly driven. Also 2-
When the four-wheel drive switching clutch 45 is turned ON, the driving force of the output shaft 22 is transferred to the output sprocket 31 and the chain 33.
It is transmitted to the inlet block block 32 via.

The seven langes 34 fixed to the outer end of the output shaft 22 are connected to the rear propeller shaft 8 described above, and the rear wheels 4a,
A flange 35, which is connected to the output side of the input cast brocket 32, is connected to the front propeller shaft 7 and drives the front wheels 1a and 1b.

At the top of the case 29, there are a pressure regulator valve 36, a manual valve 37. shift valve 38
is provided.

The pressure regulator valve 36 described above is connected to the input shaft 2
The pump discharge pressure of the hydraulic pump 39 provided on the input side of the hydraulic pump 1 is controlled to a constant pressure.

Further, the manual valve 37 is switched between two-wheel drive and four-wheel drive by operating the operating lever 40 by the driver, and in conjunction with this, the 2-4 wheel switching clutch 45 is operated.

In addition, the shift valve 38 is operated by the direct connection release modulator 13 by the direct connection release controller 12.
The 2-4 wheel switching clutch 45 is operated to switch between 2 wheel drive and 4 wheel drive.

Note that the oil passage 42 from the shift valve 38 is connected to the back side of the piston 43 of the 2-4 wheel switching clutch 45,
By supplying pressure oil thereto, the piston 43 moves and the clutch is turned on. Note that the low-speed and high-speed clutches 23 and 24 are similarly configured.

FIG. 4 shows the operating position of the operating lever 40, and A is the auto position, in which 2-4 wheel drive switching is controlled by a separately provided controller and automatically performed according to driving conditions. In this case, the high-speed clutch 24 is turned on, and the four-wheel drive is set only to high-speed drive.

8. C and D are manual operation positions by the driver, B position is a two-wheel drive operation position, and the 2-4 wheel drive switching clutch 45 is operated OFF. The C position is the high-speed four-wheel drive position, and the ^speed clutch 24.2-4
The wheel drive switching clutch 45 is turned on. The D position is the low-speed four-wheel drive position, and the low-speed clutch 23.2-
4-wheel drive FJ) replacement clutch 45 is turned on.

In the above, we have explained the case of a so-called part-time type 4-wheel drive vehicle, but the case of a full-time type 4-wheel drive vehicle has been explained.
The same goes for wheel drive vehicles, and the transfer in case of full-time type? 60 is shown in FIG. 5, and its structure and operation will be described below.

In this transfer 60, a transmission output shaft 61 having a drive gear 61a at one end extends in the vehicle width direction. And this drive gear 6
1a meshes with a large-diameter input gear 71a integrally formed on the outer periphery of a ring gear 71 in the inter-axle differential device 70.

This axle contact a device 70 includes the ring gear 71, a sun gear 72 arranged correspondingly to the ring gear 71, and the ring gear 71.
and a plurality of binions 73 meshing with the sun gear 72...
・73 and these binions 73...73 to bin 74
... 74, and a pinion carrier 75 supported via a planetary gear mechanism. here,
As shown in FIG. 6, a plurality of binions 73 . It is a double binion consisting of a binion 73b that meshes with the pinion 73b.

Also, one side of the inter-axle differential device F70 (right side in the figure)
includes a differential case 76, a pair of radial pinions 78, 78 rotatably fitted in a radial bin 77 whose both ends are supported by the case 76, and a pair of left and right umbrellas meshing with both the binions 78,78. A front wheel differential 80 consisting of 79 and 7 gears is arranged. A left front wheel drive shaft 81 and a right front wheel drive shaft 82 extending in the left-right direction are coupled to the bevel gears 79 and 79 of the front wheel differential device 80, respectively. It passes through the center and reaches the left front wheel, and also the right front wheel drive lll
1l182 reaches the right front wheel.

Binion carrier 75 in the inter-axle differential device 70
and the differential case 76 of the front wheel differential device 80 located on the side thereof are integrated as the same part. Further, the ring gear 71 and the binion carrier 75 (differential case 76) in the inter-axle differential 70 extend to the right in the figure beyond the front wheel differential 80, and are formed adjacent to the outer periphery of the extended portion. The ring gear 71 and the binion carrier in the inter-axle differential device 70 are connected by the same-shaped splines 85 and 86 and the slider 87 which can slide from a state fitted to one of them to a state fitted across both. A differential lock mechanism 88 that connects or separates the
is configured.

In this way, the inter-axle differential device 70, the front wheel differential device 80, and the differential lock mechanism 88 of the axle suspension gear 70 are arranged coaxially with the front wheel differential device 80 in the center.

On the other hand, an intermediate shaft 89 is arranged parallel to the axle center of the inter-axle differential device 70 and the front wheel differential device 80 at a constant distance. A gear 90 integrally formed with the intermediate shaft 89 is meshed with a gear 91 integrally formed with the sun gear 72 of the inter-axle differential device 70.
A second intermediate shaft 92 is disposed on the extension of the rain intermediate shaft 89.
A slider 95 is fitted into a spline 93.94 formed at an adjacent end of the shaft 92, and the rain intermediate shaft 89.92 is connected or separated by the sliding of the slider 95. Further, the second intermediate shaft 92 has an output gear 96.
A bevel gear 98 integral with a propulsion shaft 97 extending in the longitudinal direction of the vehicle body is meshed with the gear 96. This propulsion shaft 97 leads to a rear wheel differential device, and drives the left and right rear wheels via left and right rear wheel drive shafts extending left and right from the device.

According to the above configuration, the rotation of the crankshaft in the engine is input to the transmission, and after a reduction ratio is selected in the transmission, the rotation is transmitted from the drive gear 61a on the output shaft 61 via the input gear 71a. It is input to a ring gear 71 in an inter-axle differential device 70. The power input to the ring gear 71 is divided in the inter-axle differential device 60 and outputted from the binion carrier 75 and the sun gear 72, respectively.
The output from the binion carrier 75 drives the left and right front wheel drive shafts 81 and 82 or the left and right front wheels via the front wheel differential device 80. Also, the output from sun gear 72 is gear 9
1.90, the propulsion shaft 97 is driven through the intermediate shaft 89.92 and the output gear 96, and the left and right rear drive shafts or rear wheels are further driven through the rear wheel differential. In this case, the spline 93°9 of the intermediate shaft 89 and the second intermediate shaft 92
If the slider 95 fitted across the two wheels is slid as shown by y in FIG. 5 to separate the rain intermediate shaft 89°92, the output of the engine will be transmitted only to the front wheels. In other words, by operating the slider 95, you can switch between two-wheel drive and four-wheel drive.
It is possible to use wheel drive and operate ABS.

In addition, the state in which the rain intermediate shafts 89 and 92 are combined, that is, 4
In the wheel drive state, the slider 87 in the differential lock mechanism 88 of the inter-axle differential device 70 is slid as shown by the chain line X, and the ring gear and pinion carrier 75 are
If it is fitted across splines 85 and 86 in
By coupling the ring gear 71 and the binion carrier 75, the differential function of the inter-axle differential device 70 is eliminated, and a differential lock can be performed.

(Effects of the Invention) As explained above, according to the present invention, when the brake is applied, the presence or absence of ABS operation is detected, and when the ABS operation is started, the direct connection state of the front and rear wheel drive systems is detected. The anti-skid braking system (ABS) is activated after the anti-skid brake system (ABS) is released and the two-wheel drive state is established, so ABS, which is conventionally used in two-wheel drive vehicles, can also be applied to four-wheel drive vehicles. Not only can it be used to perform good brake control even in 4-wheel drive vehicles, but it can also be used to switch to 2-wheel drive when ABS control is required, that is, when ABS III Ill actually starts. By having the 2-4 wheel drive switch be performed only when the brake pedal is pressed, it is possible to prevent the 2-4 wheel drive switching from being performed unnecessarily in the case of so-called "single depression" or repeated depression of the brake pedal. The effect of switching on the driving performance of the vehicle can be reduced.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the drive system and AB S fil In system of a four-wheel drive vehicle equipped with the brake control device of the present invention, Fig. 2 is a flowchart showing the contents of A B S 1ill I21I, and Fig. 3 Is it a part-time 4 wheel drive transf? Fig. 4 is a front view showing the 2-4 wheel switching operation lever, Fig. 5 is a sectional view showing the transfer of a full-time four-wheel drive vehicle, Fig. 6 is the arrow shown in Fig. 5 - ■ FIG. 7.8...Propeller shaft 10...Transmission 20...Transfer 23...Low speed clutch 24...High speed clutch 31...Sprocket 3
3...Chain 4o...Operation lever 45.
... 2-4 wheel drive switching clutch 70 ... Inter-axle differential device 71 ... Ring gear 72 ... Sun gear
73...Binion 75...Binion carrier 80...Front wheel differential device Figure 1 Figure 6 (Voluntary) Procedure ``n1 To the Commissioner of the Patent Office September 1986
962, Name of R Ming Relationship with the case of a person who corrects the brake control device of a four-wheel drive vehicle 3° Patent applicant address 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Name
Mazda Motor Corporation 4, Agent 5-2-16 Roppongi, Minato-ku, Tokyo 106, Number of inventions increased by amendment None 8 Contents of amendment 1) Page 3 of the specification, line 10 “In the case,” After that, insert ``For example, when in part-time 4-wheel drive mode or full-time differential lock mode.'' [ It is possible to cancel the four-wheel direct connection state, for example by releasing the differential lock, or by switching from 4vA drive to two-wheel drive.'' 4) Page 4 of the same page, 5-6 (1 [4-wheel drive... drive] is corrected as [Removal letter MJ from front and rear wheels directly connected state. 5) Line 8 of the same page [2-4 wheels] Correct the driving force to "from a state in which the front and rear wheels are directly connected to a state in which they are released." 6) In line 16 of the same page, [4-wheel drive is changed to 2-wheel drive], correct the state of 1 front and rear wheels being directly connected to the released state J. 7th page 14, lines 17-19 [2-4 wheel drive... is carried out. ” to be deleted. 8) After "operated" on page 15, line 9 of the same page, [when the brakes are applied, the front and rear wheels can be switched from the directly connected state to the released state regardless of the lever position, regardless of the lever position. Switching between direct connection and release is controlled by a separately provided controller and is automatically performed according to driving conditions. ” is inserted. 9) On page 19, line 15, ``Drive.'', it says, ``In the state where the intermediate shafts 89 and 92 are connected, that is, in the four-wheel drive state, the slider 87 in the differential lock mechanism 88 of the inter-axle differential device 70 is If it is slid as shown by the chain line X and fitted across the splines 85 and 86 in the ring gear and the binion carrier 75, the ring gear 11 and the binion carrier 75 are coupled, and thereby the axle shaft rocking device γ0 The differential function of the front and rear wheels is eliminated, allowing the differential lock to be performed.By operating the slider 87, the front and rear wheels can be directly connected and released. 10) On the same page, change ``In this case,'' to ``Also, as shown in Figure 5,
” he corrected. 11) In the 18th line of the same page, "as indicated by the demotion y" is corrected to "the position of line 11 y". 12) In line 20, line 3 of the same sentence, ``koto'' is corrected to ``kotomo.'' 13) Delete "Na,......" from lines 4 to 13 of the same page. 14) In line 18 of the same page, ``cancellation'' is corrected to ``cancellation or''. 15) On page 21, line 4, ``2-wheel drive J'' is corrected to ``a state in which the front and rear wheels are directly connected to a released state.'' 16) In the 8th line of the same page, ``2-4 wheel drive'' is corrected to ``from a directly connected state of the front and rear wheels to a released state.'' 17) Line 9 of the same page: ``2-4 wheels'' from the directly connected state of the front and rear wheels to the released state.''
I am corrected. 18) On the 11th line of the same page, change "I can do it." to "I can do it." Corrected with j.

Claims (1)

[Scope of Claims] A brake control device for a four-wheel drive vehicle, comprising a four-wheel drive device that drives front and rear wheels, and an anti-skid brake system that controls braking force during braking and prevents the wheels from locking up. an operation detection means for detecting operation of the anti-skid brake system; and when the operation detection means detects the operation of the anti-skid brake system, the front and rear wheel drive systems of the four-wheel drive device are directly connected to each other. A brake control device for a four-wheel drive vehicle, comprising a release means for releasing the brake.