JPS62105756A - 4-wheel-drive vehicle - Google Patents

Abstract

PURPOSE:To reduce interference of a rear wheel with a front wheel which takes place at the time of braking by installing brakes on front and rear wheels respectively, and carrying out the antilock control of brakes on the rear wheel side by relaxing the reference value for judging whether a wheel is about to be locked or not. CONSTITUTION:An antilock control device 9 has a front wheel control part 9a which separately controls the modulators Mfl, Mfr for front wheels Wfl, Wfr, and a rear wheel control part 9b which simultaneously controls the modulators Mrl, Mrr for rear wheels Wrl, Wrr. And, signals from detectors 10l, 10r for detecting the wheel speeds of the front wheels are inputted in the front wheel control part 9a, while signals from detectors 11l, 11r for detecting the wheel speeds of the rear wheels are inputted in the rear wheel control part 9b. In the rear wheel control part 9b, a reference value for judging whether a wheel is about to be locked or not, is set more loosely than that in the front wheel control part 9a.

Description

Detailed Description of the Invention A5 Purpose of the Invention (1) Industrial Field of Application The present invention is characterized in that a bar-no-unino 1- is connected to one of the front and rear axles, and the other axle has a relative rotation speed. The present invention relates to a four-wheel drive vehicle connected to a power unit via a torque transmission mechanism in which the amount of torque transmitted increases as the speed increases.

(2) Prior Art Conventionally, in such four-wheel drive vehicles, brakes are generally attached to each axle.

(3) Problems to be Solved by the Invention Incidentally, in the above vehicle, the front and rear axles are almost rigidly connected at all times, so if the braking oil pressure becomes excessive during sudden braking, all wheels will lock at the same time. Therefore,
Compared to front-wheel or rear-wheel drive vehicles, stability during braking is improved, but stability against external disturbances and steering performance are still lost. Therefore, it is desirable that the brake device has an anti-lock function.

However, anti-[1-slip brakes] basically try to maintain the slip rate of each wheel around the appropriate value by controlling the play torque for each wheel or each axis. It is necessary that the speed of the wheels or each axle can be varied independently. On the other hand, in a vehicle where the front and rear axles are connected almost rigidly, the front and rear axles interfere with each other. - If anti-lock control is used, appropriate control cannot be obtained.

If the center axle after one force and +iiT is connected almost rigidly, the wheels on one axle should have an appropriate slip rate.
If so, the slip rate of the wheel on the other axle will inevitably be approximately the appropriate value.

Therefore, if the brakes are installed only on the front wheels to obtain full braking force and anti-lock control is applied to those brakes, the above-mentioned problem can be solved, and the present applicant also believes that We are proposing a four-wheel drive vehicle with a similar configuration.

However, if the front wheel brake is used to provide full braking, the play of the front wheel and the 1' t tu of the front wheel will become a dog, and increasing the capacity may be a national problem in terms of space.

The present invention has been made in view of the above circumstances, and in order to reduce the burden on the front wheels, a brake is also installed on the rear wheels, and the anti-seat control of the rear wheels is performed without interference from the rear wheels to the front wheels. An object of the present invention is to provide a four-wheel drive vehicle that is designed to minimize the size of the vehicle.

+IN configuration of B1 invention Means for solving the problem According to the present invention, brake L--4- is attached to each axle of both axles, and the brake hydraulic system for controlling the hydraulic pressure of each brake has an axle An anti-lock control device is attached that controls the pressure of the front wheel to loosen when the front wheel is about to enter a 1:1 lock state, and the anti-lock control device controls the brakes of the front wheels individually. Control unit and rear wheel brake?
]ll has a rear wheel control section, and the rear wheel control section has a rear wheel control section,! 1 "Basic for determining whether the wheel is likely to enter the l-cock state (11! The value should be set more gently than the front wheel side i1 [1 part.

(2) Effect The rear wheel slip rate is determined by the rear wheel control unit. ! ;Junior A1/I
By setting the value gradually smaller, the front/F2 J
, and the interference from the rear wheel to the rear wheel can be kept to a minimum.

() Example Hereinafter, an example of the present invention will be explained with reference to the drawings. First, in FIG. 1, a pair of left and right front wheels Wr1.Wf
r and a pair of left and right rear wheels Wrn and Wrr are respectively suspended at the front and rear parts of a vehicle body (not shown).

Left and right front wheels Wf6. A pair of front axles Ar11. Afr are mutually connected via a front differential device Dr, and left and right rear wheels Wrβ.

A pair of rear axles Arfl, Arr connected to Wrr respectively
are interconnected via a rear differential device Dr. A power unit 7)P including an engine and a transmission is connected to the human power section of the front differential D''.

Further, a rear propulsion shaft Pr is connected to the input part of the rear differential D". This rear propulsion shaft Pr is coaxially connected to the front propulsion shaft pr via a viscose clutch 1 as a torque transmission mechanism. The driving force of the power unit P is transmitted to the front propulsion shaft PI.

The viscose clutch 1 has a high viscosity oil and a small amount of oil that allows thermal expansion of the high viscosity oil in a sealed oil chamber 4 defined by a clutch outer 2 and a clutch inner 31UIc that are rotatable relative to each other. A plurality of outer clutch plates 5 spline-coupled to the clutch outer 2 and a plurality of inner clutch plates 6 spline-coupled to the clutch inner 3 are arranged in an overlapping manner. Moreover, each board 5,
6 is provided with an opening (not shown) that allows oil to flow therethrough, the clutch outer 2 is integrated with the ON part Jtu advance shaft PfL, and the clutch inner 3 is integrated with the rear propulsion shaft Pr.

In this viscose clutch 1, when relative rotation occurs between clutch outer 2 and clutch inner 3, both clutch plates 5 and 6 rotate relative to each other while shearing high viscosity oil, and both latch plates 5 and 6 rotate. Viscous transmission of torque takes place.

Furthermore, when the relative rotational speed increases further, the rise in oil temperature creates a complicated temperature gradient in both the tara nochi plates 5 and 6, and due to the synergistic effect of the strain caused by this and the pressure increase in the sealed oil chamber 4, the adjacent F between both latches 5 and 6? ! t8!
The retaining portion or gap is scratched to create a small portion, and as a result, frictional torque transmission is performed between the clutch outer 2 and the clutch inner 3.

According to such a viscose clutch l, there is a gap between the front propulsion shaft Pf and the rear propulsion shaft Pf, that is, the front axle A[
N, Afr and the rear axles Arc, Arr are always substantially rigidly connected, and the front wheels Wrl, Wrr and the rear wheels WrLWrr interfere with each other.

Front wheel Wfj! , Wfr are equipped with brakes BfN and Bfr, and rear wheels Wry and Wrr are equipped with brakes of relatively small capacity 4''BrCBrr.

In FIG. 2, each brake 131 (!, Bfr, Br
j! , Brr, the brake hydraulic system 7 controls the hydraulic pressure of
A tandem type master cylinder 8 having a pair of output boats 8; r 4 - [Adjust the hydraulic pressure supplied from the output port 8b of the gerator MfLMrr and other horns -C right 11:!Ugawa flake Bfr and left rear wheel play 4-13 r i!
・Shishureta Mfr, Mr7! Prepare yourself. The brake hydraulic system 7 is equipped with a hydraulic brake system 2. Rater Mfp, Mr r, Mr7
! , the anti-control system that controls the operation of Mrr.
! A pedestal holder 9 is attached.

The anti-I51 control device 1] controls the front wheels wrp, 'wr
The front wheel control section 9a which individually controls the modulators 1VIfA and Mfr of the rear wheels Wrp and Wrr, and the rear wheel control section 911 which simultaneously controls the modulators Mrj! and Mrr of the rear wheels Wrp and Wrr are fl- The signal from the detection i?3101.1Or that detects the wheel speed of the front wheel WrLWrr is 11
7) Transport door section9. ．． Powered by I, rear wheel Wri! , Wr.
Detection 2311ff, which detects the wheel speed of r, and No. 1ε from IIr are manually input to the rear wheel control section 9b.

Next, the configuration of the front wheel control section 9a will be explained with reference to FIG. 3. The part corresponding to one modulator M (1) and the part corresponding to the other modulator Mrr are basically the same Therefore, in the following, parts related to one modulator Mrl will be described with the suffix l, and parts related to the other modulator Mrr will only be illustrated with the suffix "."

In order to determine whether the wheels are about to enter the locked state, the detector 10I! The wheel speed V detected at is input to the inverting terminal of the first comparator 13g, and
The wheel acceleration 98 that is input to the arithmetic circuit 12p and obtained by the arithmetic circuit 12N is input to the inverting terminal of the second comparator 14ff and the non-inverting terminal of the third comparator [5e]. The first comparator 13N compares the reference wheel speed vll inputted to the non-reverse center bar:; It is output from the first comparator +3ff. Also the second comparator 147! Now, the reference wheel deceleration input to the non-reversing terminal -*. is compared with the wheel acceleration 90, and when 'Jwo > %1w, a signal β for relaxing the braking oil pressure is output from the second comparison ji14e.

Furthermore, the third comparator 15I! Now, a comparison is made between the base (1 town wheel acceleration +9.1 degrees) input to the inversion terminal and the wheel acceleration 9 degrees, and when *I>+Q, , the third comparator 15I! A signal α is output.This signal α
is used to determine whether the wheel speed VW is increasing or not, and the timing to continue loosening the braking oil pressure is determined based on this signal α.

First comparator 13I! The output terminal is AND gate ■672
is connected to the input terminal of the OR gate 17! !
connected to the input terminal of Also, the second comparison 34 t 4.
The output terminal of 2 is AND game 1-16f! and is connected to the input terminal of OR gate 171. Furthermore, the third comparator 1
The output terminal of 51 is connected to the input terminal of OR gate I7p.

The output terminal of AND game 1-169 is inverted and connected to the input terminal of AND game 18β, 191,
Connected to output terminal 206. Also, OR gate 17I2
The output terminal of the AND gate IEI is connected to the input terminal of the AND gate 1-18e, and the output terminal of the AND gate IEI is connected to the output 0:1;
Connected to the 9N input terminal. Furthermore, ΔND gate t-Z
The output terminal of C should be connected to output terminal 211.

In the front wheel side j3■ section 9F) configured in this way, the braking pressure is reduced from the output end 7'201.2Or (a ”
'E is output and output terminal 21i! , 21r outputs a signal to increase the braking pressure, and the output terminal 22I2.22r
A signal is output from which keeps the braking pressure constant. One modulator Mfe has output terminal 2()1211.22
7! Compared to the signal from 1+-, the other modulator Mrr is output from 20r, 21r, 22
(to the signal from R), and is activated 7, which causes both brakes Br7! , Bfr are individually controlled.

In FIG. 4, the configuration of the rear wheel control fa11 section 91.1 will be explained. This rear wheel control section 9bO)+jIS configuration is similar to the configuration of the front wheel control section 9a, and corresponds to the front wheel control section 9a. As for the part, it is designated as 16z without the letters p and r and 1j4 (illustrated with the reference numeral ``J'').

What you should pay particular attention to in the rear wheel control section 9b is the detector llj!
, 11r detects the wheel speed detected by the low select circuit 23.
This L:1-select circuit 2
The lower wheel speed selected in step 3 is input to the first comparator 13 and the calculator 12.

That is, anti-lock control is performed on the left and right rear wheels Wrβ, Wrr which is more likely to lock, that is, the wheel with a lower wheel speed, and the output terminals 20, 2
1. Both modulators Mr. with the control signal output from 22
12. The operation of Mrr is controlled at the same time.

Furthermore, in the rear wheel control section 9b, the reference value for determining whether or not the wheels are likely to anti-lock is set more gently than in the front wheel control section 9a. That is, the reference wheel speed yR+ input to the non-inverting terminal of the first comparator 13
is set larger than the reference wheel speed VR in the front wheel control section 9a (Vll'> Vll),
When vR'>v, the first comparator 13 outputs a signal λ' for relaxing the braking oil pressure. In addition, the second comparator 14 inputs the base (V wheel deceleration -%/we
" is the base <1 (wheel deceleration -
Greater than 9.4° (-98°r > v,,
. ), and when 95°'>94, the second comparator 14 outputs No. 13 β' which loosens the braking oil pressure.

Next, to explain the operation of this embodiment, each brake (B r N) is activated while the vehicle is running.

Bfr;Brj! , Brr and each wheel V/l e, Wf r ; Wr Il, W
Let us assume that when applying braking force to r r, the brake oil pressure becomes excessive. At this time, in the rear wheel control unit 9b of the unlock control device 9, the reference value for determining whether or not the rear wheels WrN and Wrr are likely to lock is gentler than that of the front wheels. , Wrr slip rate can be suppressed to be smaller than that of 1111 wheels. Zunawara rear wheel Wr! , Wrr brake torque is rear wheel drive F on the road surface
Reduced by JJ force, rear wheel Wrt! , Wrr to 1
11 imports Wr7! , Wrr to -[-4 can be suppressed to a small value, so it is possible to perform good anti-one-click control.

The front wheel control brake 9a is a front wheel monoulator M.
Since fLMrr is controlled individually, the brake pressure and driving stability are both excellent! , B is received. Zunawara, front wheels Wf#, Wrr and rear wheels Wr1. In the 41IIQ drive insect where Wrr is almost rigidly connected, 1iij import Wrl! , Wfr's control rear wheel W r 1 .

Since it affects Wrr, whichever of the previous 11 own speeds is higher, which one is the highest rake Mf? , Mf", one of the front wheels W (1, Wrr) is IR/R which causes 19.
It has the same characteristics as ii, and its shadow pi is both rear wheels Wre and W.
rr, the rear wheels Wrf and Wrr slip, resulting in poor running stability.

Also, the front wheels Wr+ with high distribution!, Wrr, Il(
Both brakes [3f[,
It is obvious that the braking distance will be extended by using the l:J-select circuit 8 which performs the same 11.1 control of the 13fr.

In the above embodiment, the modulators Mr1 and Mrr on the rear wheel side are
1]-Select method (I tried to control them simultaneously, but even if I tried to control them individually, it still doesn't work.

According to the present invention, brakes are installed on one wheel and the rear wheel respectively, and the anti-rotation control of the brake on the rear wheel side is controlled by i[1]. IUi J-ru group i (The value has been relaxed to 2, so interference from the rear wheel to the front and rear wheels can be kept to a minimum. This is a heavy vehicle in which the front and rear wheels are almost rigidly connected, so it is possible to perform appropriate anti-lock control regardless of the number of brakes, and to reduce the front wheel brake load.
reduction is possible.

4. Explanation of the drawings The drawings show one embodiment of the present invention, and Fig. 1 is a schematic diagram of the drive system, Fig. 2 is a schematic diagram of the Ll brake system, and Fig. 3 is a schematic diagram of the Ll brake system.
The figure is a schematic diagram of the front wheel control section, and FIG. 4 is a schematic diagram of the rear wheel control section.

Claims (1)

[Claims] A power unit is connected to either the front or rear axle, and the other axle is connected to the power unit via a torque transmission mechanism that increases the amount of torque transmitted as the relative rotational speed increases. In four-wheel drive vehicles,
Brakes are attached to the wheels of both axles, and the brake hydraulic system that controls the hydraulic pressure of each brake is equipped with an anti-lock control device that controls the brake hydraulic pressure to loosen when the wheels are about to enter a locked state. The anti-lock control device has a front wheel control section that individually controls the brakes of the front wheels and a rear wheel control section that controls the brakes of the rear wheels. A four-wheel drive vehicle characterized in that a reference value for determining whether or not the front wheel drive is set is set more gently than a front wheel control section.