JPS621665A - Four-wheel drive car with antilock braking device - Google Patents

Abstract

PURPOSE:To make improvements in an antilock effect, by installing a braking hydraulic pressure reducing device, letting braking hydraulic pressure at the rear-wheel side forcibly reduce at the time of operation of an antilock mechanism, in a braking device. CONSTITUTION:At the time of braking as a car is driving in a four-wheel drive state, any of respective wheels Wfl, Wfr, Wrl and Wrr is on the verge of being locked, an antilock mechanism 9 operates whereby each position of both first and second solenoid selector valves 10 and 11 is selected, connecting a rear-wheel braking mechanism to a reservoir R With this connection, braking hydraulic pressure in this rear-wheel braking mechanism is remarkably reduced. However, these rear wheels Wrl and Wrr come to rotate in response to rotation of front wheels Wfl and Wfr in consequence, so that rotation of these rear wheels Wrl and Wrr is controllable by antilock control of these front wheels Wfl and Wfr, thus a sufficient antilock effect is securable.

Description

[Detailed Description of the Invention] A0 Objective of the Invention (1) Industrial Application Field The present invention relates to a front differential device that interconnects a pair of front axles connected to left and right front wheels, and The present invention relates to a four-wheel drive vehicle with an anti-lock brake device, in which a rear differential device that interconnects a pair of consecutive rear axles is directly connected, and the brake device is provided with an anti-lock mechanism for at least the front wheels.

(2) Conventional technology Four-wheel drive vehicles are being developed in order to further improve the driving performance of vehicles and their driving performance on snowy roads with a low coefficient of friction. Attempts have also been made to equip lock brake devices.

(3) Problems to be Solved by the Invention However, if the anti-lock brake device used in conventional two-wheel drive vehicles is applied as is to four-wheel drive vehicles, problems will arise. That is, in a four-wheel drive vehicle, the front axle and the rear axle influence each other, so each wheel restrains each other, making it impossible to obtain a sufficient anti-lock effect.

The present invention has been made in view of the above circumstances, and is equipped with an anti-lock brake device that improves the anti-lock effect by reducing the rear wheel braking hydraulic pressure and performing anti-lock control only on the front wheels when the anti-lock is activated. The purpose is to provide four-wheel drive vehicles.

B1 Structure of the Invention (1) Means for Solving the Problems According to the present invention, the brake device is provided with a braking oil pressure reducing means for forcibly reducing the rear wheel braking oil pressure when the anti-lock mechanism is activated. .

(2) Function When anti-lock is activated, the rear wheel brake hydraulic pressure is reduced by the function of the brake hydraulic pressure reducing means, so by performing anti-lock control on the front wheels, the rotation of the rear wheels can be controlled and sufficient anti-lock is achieved. A locking effect can be obtained.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. First, in FIG. 1, a pair of front wheels Wf1, Wfr and a pair of rear wheels Wr1. Wrr are respectively suspended at the front and rear parts of the vehicle body (not shown), and both front wheels Wf1. W
Brake mechanism Bfl is installed on fr and both rear wheels WrLWrr.
, Bfr; Brl, and Brr are attached, respectively.

Left and right front wheels Wf1. A pair of front axles Afl, Afr connected to Wfr, respectively, are connected to each other via a front differential 1, and a pair of rear axles Arf, Arr connected to left and right rear wheels Wrll, Wrr, respectively, are connected to each other via a front differential 1. are interconnected via.

A front propulsion shaft 3 and a rear propulsion shaft 4 are connected to the input parts of the front differential 1 and the rear differential 2, and a central differential 5 is connected to these propulsion shafts 3.4. and are interconnected. A power unit P including an engine and a transmission is connected to an input portion of the central differential device 5.

The central differential 5 includes a locking mechanism 6, and when the locking mechanism 6 is activated, the front and rear propulsion shafts 3.4 are directly connected, resulting in a four-wheel drive state.

In FIG. 2, each brake mechanism Bf#.

A brake device B including Bfr;Brf and Brr is a brake mechanism Bfj! , Bfr; Brff, Br
Brake hydraulic modulators Mft', Mfr; Mr(1, Mrr
It consists of

Each brake hydraulic modulator Mff, Mfr; Mrj!
, Mrr applies braking oil pressure to each brake mechanism Bfj! according to the output oil pressure of the tandem mask cylinder Mc. ,Bfr;B
The oil pressure from one output port door of the mask cylinder Mc is supplied to the brake oil pressure modulators Mff and Mrr, and the oil pressure from the other output port 8 is supplied to the brake oil pressure modulators Mfr,
Supplied to Mrl.

This brake device B is attached with an anti-lock mechanism 9, and when the anti-lock mechanism 9 is activated, each brake hydraulic modulator Mfl, Mf r ;Mr 1
．． In order to reduce the output oil pressure of Mr r, that is, the braking oil pressure, each brake oil pressure modulator Mf l, Mf r
; Generates Ha hydraulic pressure to operate Mr l and Mr r.

According to the invention, the rear wheel brake mechanism Brl.

In order to reduce the braking oil pressure of Brr, a first electromagnetic switching valve 10 as a braking oil pressure reducing means is interposed between one output port door of the mask cylinder Mc and the right rear wheel brake oil pressure modulator Mrr, and the other output port A second electromagnetic switching valve 11 as a brake hydraulic pressure reducing means is interposed between the brake hydraulic pressure modulator 8 and the left rear wheel brake hydraulic pressure modulator Mrl.

These electromagnetic switching valves10. Normally, il is in a position where it can supply the hydraulic pressure from the Okayama cupboard door 8 of the mask cylinder Mc to both brake hydraulic modulators Mrr and Mrj2, but during excitation, both brake hydraulic modulators Mr.
Switch CMrr to the position where it is connected to the reservoir R of the mask cylinder Mc.

Controller 12 for controlling the operation of both solenoid valves 10.11
A signal indicating the operating state is inputted from the anti-lock mechanism 9, and a signal indicating the operating state is inputted from the locking mechanism 6 of the central differential device 5, and the controller 12 controls whether the locking mechanism 6 is When the anti-lock mechanism 9 is activated in the activated four-wheel drive state, the solenoid valve 10 is activated.
．． 11, rear wheel brake hydraulic modulator M
Connect rr and Mrl to reservoir R.

Next, to explain the operation of this embodiment, each wheel Wf1, Wf r HW is activated during braking when driving in four-wheel drive with the central differential device 5 locked by the locking mechanism 6.
r j2. When one of Wr r is about to lock, the anti-lock mechanism 9 is activated and the first one is about to lock. The position of the second electromagnetic switching valve 10.11 is switched. That is, the first and second solenoid valves 10.11 operate the rear wheel brake mechanisms Brr, B via the rear wheel brake hydraulic modulators Mrr, Mrl.
The rf is switched to the position where it is connected to the reservoir R, so the rear wheel brake mechanism Brr, Br! ! The braking oil pressure will be significantly reduced.

However, the rear wheels Wrl and Wrr are the front wheels Wff and Wf.
In response to the rotation of the front wheels Wfj2. Wfr
The anti-lock control allows the rotation of the rear wheels Wr (1, Wrr) to be controlled, and a sufficient anti-lock effect can be obtained.In other words, even when a slip is detected on the rear wheel side, the braking hydraulic pressure of the front wheels Wfl, Wfr remains unchanged. By controlling the rear wheel
Anti-lock control of JJrl and Wrr can be sufficiently performed.

Note that when the locked state by the lock mechanism 6 is released, a normal anti-lock operation is performed.

Although the above embodiment has been described in a four-wheel drive state in which the central differential device 5 is locked, the present invention can also be applied to a four-wheel drive state of a part-time four-wheel drive vehicle, and the front and rear differential devices 1 ．．
It is also applicable to a four-wheel drive vehicle in which the two are connected via a viscous coupling.

C0 Effects of the Invention As described above, according to the present invention, the brake system is provided with a brake hydraulic pressure reducing means that forcibly reduces the rear wheel brake hydraulic pressure when the anti-lock mechanism is activated, so that the rotation of the rear wheel is reduced. It can be controlled on the front wheel side and a sufficient anti-lock effect can be obtained.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a schematic diagram of a drive system, and FIG. 2 is a hydraulic circuit diagram of a brake device. 1... Front differential gear, 2... Rear differential gear, 9...
・Anti-lock mechanism, 10.11... Solenoid switching valve as means for reducing braking oil pressure, Afj! , Afr...Front axle, Arl, Arr...Rear axle, B...Brake device, Wf CWf r...Front wheel, Wr l, Wr r
−・−Rear wheel application person Honda Motor Co., Ltd. Figure 1

Claims (1)

[Claims] A front differential device that interconnects a pair of front axles connected to left and right front wheels, respectively, and a rear differential device that interconnects a pair of rear axles connected to left and right rear wheels, respectively, are directly connected,
In a four-wheel drive vehicle with an anti-lock brake device in which the brake device is equipped with an anti-lock mechanism for at least the front wheels, the brake device includes a mechanism for forcibly reducing rear wheel braking hydraulic pressure when the anti-lock mechanism is activated. A four-wheel drive vehicle equipped with an anti-lock brake device, characterized in that a brake hydraulic pressure reducing means is provided.