JPS62105758A - 4-wheel-drive vehicle - Google Patents

Abstract

PURPOSE:To suppress the slip ratio of rear wheels to be small by installing brakes on wheels, and avoiding increase in brake oil pressure until a certain period of time has elapsed after said rear wheels get rid of a condition that these wheels are about to be locked. CONSTITUTION:A brake oil pressure device 7 has modulators Mfl, Mrr which regulate oil pressure fed from an output port 8a and lead the oil pressure to brakes Bfl, Brr, and modulators Mfr, Mrl which regulate oil pressure fed from an output port 8b and lead the oil pressure to brakes Bfr, Brl. An antilock control device 9 consisting of a front wheel control part 9a which separately controls front wheel brakes, and a rear wheel control part 9b which controls rear wheel brakes, is provided on the brake oil pressure device 7. The rear wheel control part 9b is constructed in such a way that increase in brake oil pressure is avoided until a certain period of time has elapsed after wheels get rid of a condition that these wheels are about to be locked.

Description

[Detailed description of the invention]

A1 Purpose of the Invention (1) Industrial Field of Application The present invention provides a power unit connected to one of the axles after IFi, and a power unit connected to either the front or rear axle in accordance with the relative rotational speed. The present invention relates to a four-wheel drive vehicle that is connected to a power unit via a torque transmission mechanism in which the amount of torque transmission is constant. (2) Prior art Conventionally, in such four-wheel drive/υ type vehicles, each wheel is generally equipped with a brake. (3) Problems to be solved by the invention By the way, in the above vehicle, the front and rear axles are almost always connected rigidly, so if the braking oil pressure becomes excessive during a sudden brake operation, all wheels lock at the same time. Therefore,
Compared to front-wheel or rear-wheel drive vehicles, the stability during braking is improved by 1-2, but the stability against external disturbances and the loss of steering performance remain unsolved. Shitka-, Teshire-1=
[Device C, Nianchi I] It is desirable that it has a locking function and is fully functional. However, the anti-wheel drive system basically controls the brake torque for each wheel or axle to maintain the slip ratio of each wheel around the appropriate value. It is necessary that the speed of each +i (transport or each axle) can be varied independently. On the other hand, in a vehicle where the front and rear axles are approximately rigidly connected, after 11 forces the i1i wheel is in phase 7j: Because of the interference, each play = j
If the anti-lock system J311 is used, appropriate control cannot be obtained. Ichibu J, before and after! 1 (If the wheels are connected almost rigidly, if an appropriate slip rate is given to the wheels on one axle, the slip rate of the wheels on the other axle will inevitably be approximately the appropriate value. If you install a plate only on the 1iif wheel to obtain full width control +) and perform anti-lock control on those brakes, the above-mentioned problem can be solved.
The present applicant is also proposing such a four-wheel drive vehicle with +14 configuration. However, if only one wheel, 1"j4-, is responsible for braking the entire width, the front wheel's 1"j4 will become a person, and if increasing its capacity is a national problem in terms of space. The present invention has been made in view of this situation, and in order to reduce the burden on the front wheel brakes, the rear 'IQ' is also equipped with a flywheel 1-, and the rear wheel flywheel 4's - is mounted. ] The object of the present invention is to provide a four-wheel drive vehicle in which the torque control is performed so as to minimize the movement from the rear wheels to the front wheels.

30 Structure of the Invention + 11 Means for Solving the Problems According to the present invention, brakes 1/- keys are respectively attached to the heavy wheels of both axles, and the brake hydraulic system for controlling the hydraulic pressure of each brake includes An anti-lock control device is attached that controls the G brake hydraulic pressure to be released when the G brake is about to enter a locked state. Control the play of the circle
The rear wheel control section is configured to avoid an increase in brake hydraulic pressure until a certain period of time has elapsed after the wheel exits the state where it is likely to crash. 2) Effect During anti-lock control of the rear wheels, until a certain period of time has passed after the rear wheels are out of a state where they are about to lock up, the rear wheels will not be allowed to play. Since the slip rate of Pl is kept low, the interference with the rear (and front wheels) seems to be small. In the figure, a pair of left and right songs/transportation Wf7I
, Wrr and the left L1 pair of rear wheels Wr1. Wrr is suspended at the front and rear parts of a vehicle body (not shown), respectively. Left and right front wheels Wff! , a pair of front axles AI connected to Wfr, respectively! ! , Arr are connected to each other via a front differential Df, and the left and right rear wheels Wr (!. A pair of rear axles ArCAr connected to Wrr are connected to each other via a rear differential 1) r. be done. A power unit P including an engine and a transmission is connected to an input portion of the front differential device Dr. Further, a rear propulsion shaft Pr is connected to the human power section of the rear differential device Dr. This rear propulsion shaft Pr is connected to the front 11F 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 Pf. Viscose clarinet 1. In the sealed oil chamber 4 defined between the latch 2 and the clutch inner 3, there is a high viscosity oil and evening air that allows thermal expansion of the high viscosity oil. 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. In addition, each machine 5.6 is provided with an opening 11 (not shown) that allows oil to flow, the clutch outer 2 is connected to the front propulsion shaft ■]r, and the clutch inner 3 is connected to the rear H [paraxial Pr will be integrated into. When this viscose clutch 1 rotates between the clutch outer 2 and the 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 relative to each other while shearing the high viscosity oil. , 6, torque is viscously transmitted between them. Furthermore, when the relative rotational speed increases further, a complicated temperature gradient occurs in both clutch plates 5 and 6 due to the rise in oil temperature.
Due to the synergistic effect of the strain caused by this and the pressure increase in the sealed oil chamber 4, a frictional engagement part or a part with an extremely small gap is created between the two adjacent clutch plates 5, 6, and as a result, the clutch outer 2 and Torque is frictionally transmitted through the clutch inner 3 II. According to such a viscose clutch 1, the I) η section propulsion shaft 1) f and the rear propulsion shaft Pr, that is, the front axles Afe, Afr and the rear axles Arl, Arr, are always almost rigidly connected. The front wheel Wf 7! ,
Wr r, +3 and the rear wheels Wrff, Wrr interfere with each other. Front wheel Wf7! , Wfr are equipped with brakes E3 (1, Grr), and rear wheels Wrl, Wrr are equipped with brakes Brff, Brr with relatively small capacities. In FIG. 2, each brake Bfj!, Brr. , a brake hydraulic system 7 that controls hydraulic pressure 8 of Brr.
adjusts the oil pressure supplied from the tandem mask cylinder 8 having a pair of output boats Ha, 8b and one output boat 8a, and operates the brake gear for the left n; one wheel brake orp and the brake for the right rear wheel Brr4. J <Moji 1 Rator M
f (!, M r r and the output boat 8b on the flu side
Even if the hydraulic pressure supplied from In order to prevent the lf ring from entering the 11]// state, the modulators Mfl, Mrr, M
rl, Mrr's (1 (1)
A control device 9 is installed.
The front wheel control unit 9, 1 that controls the modi 1r of rr to 1rl and Mfr (1) J separately] 11, and f&l/2W r
e, W r r (7) Ten Schreter M r e,
Detector 10LI (signal from lr)1;
Detection 2: 1llll? which detects the wheel speeds of the rear wheels Wrp and Wrr. , llr are input to the rear wheel control section 9b. Next, the configuration of the I width control section 9a will be explained with reference to FIG. Therefore, in the following, the parts related to one modi and rate Mfff will be described with the subscript p, and the parts related to the other modi I-rake Mrr will be described with the subscript r. It is only shown with . 1'1 whether the wheels are about to enter the lock state
1. In order to determine the speed of the wheels detected by the detector lOe,
, is input to the inverting terminal of the first comparator 13I2, and is also input to the arithmetic circuit 121, and this arithmetic circuit 12p
ZIj et al.1'1. Wheel acceleration 0. is the second comparator 141
! Inversion of ;;1st child and 3rd comparator 157! Each of the 11 reversals requires 1 liter of human power. In the first comparator 13N, the ratio axis between the wheel speed V and the wheel speed V8 is performed, and v'
, > v, , I, the first comparator 131 outputs λ, which is used to loosen the braking oil pressure. Also, the second comparator 147
! Then, the bale (de i! wheel deceleration -94o inputted to the 11 reversal end t) is compared with the iJi wheel acceleration 98, and when -</i.>Qll, the braking hydraulic pressure is loosened. No. 15 β is output from the second comparator 142.Furthermore, in the third comparator 151, a comparison is made between the 7 bales [((wheel acceleration T9°.) and the heavy wheel acceleration Q8. 〉(9〉), a signal α is output from the third comparison 23151!. This signal α determines whether the wheel speed VW is increasing. It is for life,
The number α is used to determine how long it takes to keep the brake oil pressure warm. First comparator 137! The output terminal of is A N1. ) game)
-16e is connected to the input inductor, and OI'<
It is connected to the input terminal of gate 17β. Also the second comparator 147! If the output terminal is AN I) game 1-167! and OR gate】77! connected to the input terminal of Furthermore, the output terminal of the third comparison 2ii ls e is 01 ng 1
-17ρ input terminal. A N +') game 1-1+1 (7) output v;! The first child is connected to the input terminal of the inverted CAN D gate 18L 19β, and is also connected to the output terminal 201. Further, the output terminal of the OR gate 17n is connected to the input terminal of the ΔN I) gate 18p, and the AND gate h l 8
The output of ◇: 1; child is output);) is connected to the i child 221, and is inverted and connected to the input terminal of AAND data 1-191. Furthermore, A N D gate 197
! The output terminal of is connected to the output terminal 21p by 1 Vt. In the front wheel control section 9b configured in this way, the output terminal 2
A signal to reduce the braking pressure is output from 06.2Or, and a signal to increase the braking pressure is output from the child 21ff and 2tr, and a signal to increase the braking pressure is output from the output terminal 22L22.
A signal that maintains the current level is output. One modulator M
(77 is activated by U7, 11 colors per 11 to 5 packets from output satin 201.21L 227!, and the other modulator Mfr responds to the output O: ij 2 Or, 21r, 22r). Both brakes B
(1. Brr's unloading control is performed individually. In FIG. 4, the configuration C of the rear wheel control section 9b) will be explained. is similar to the structure of FF11 Part 9.]
Regarding the part corresponding to the front wheel control section 9a, all rooms ρ,
The same reference numerals are shown as a and 1 instead of illustrating the same reference numerals. The rear wheel control unit 9b selects the special G note ``1 should be detection (i'j
The wheel speed detected by r1lL11r is manually input to the 1-1-select circuit 23, and the lower wheel speed selected by this low select circuit 23 is the first comparison 3.
313 and the arithmetic unit J2. In other words, the left and right rear wheels Wr7! , Wrr, the anti-lock control is performed according to the wheel that is more likely to lock and the wheel speed is lower, and the output terminal 20
．． 21. Is the operation of both modulators MrLMrr simultaneously controlled by the control signal output from 22? ff1l is done. Moreover, in this rear wheel control section 9b, a delay circuit 2 is connected between the output terminal of the first comparator 13 and the input terminal of the OR gate 17.
4 is interposed. As shown in FIG. 5 (8), this delay circuit 24 outputs a high level signal in response to the rising edge of the signal λ of the first comparator 13, and is constant from the rising edge of the signal λ. For example, a high-high level signal is maintained and output for 0.5 to 1 second between U and 5'F. According to such +j4 formation G, the first comparison 2: s t
After the signal λ of 3 reaches the [:1- level, for a certain period of time'F
The output of the OR gate 17 is at a high level until the time elapses, and therefore, the output of the AND gate 19 output 'r:B721 does not reach a high level during that time, and the brake hydraulic pressure of the rear wheels Brff and Brr will not increase pressure. Next, to explain the operation of this embodiment, each play = F B f
l,Bfr;Br7! , Brr to each wheel Wf1. WEr; Wrff, W
Suppose that when the braking force is changed to r r, the brake oil pressure becomes excessive. At this time, the rear wheel control section 9b controls the rear wheel Wr1. It is determined that Wrr is likely to increase by -1, outputs the signal λ2β, outputs a pressure reduction signal from the output terminal 20, and reduces the brake hydraulic pressure of the rear wheels Wr# and Wrr. When the possibility of wheel lock disappears due to brake oil pressure reduction, No. 13 β and λ become [co-level], and output terminal 2
The output of 0 becomes [1-re.\r. However, until a certain period of time has passed after No. 13 λ becomes low level, 01
Since the output of the AND gate 17 is at a high level, the output of the AND gate 18 becomes a high level, and a signal for keeping the brake oil pressure constant is output from the output terminal 22. Therefore, during that time, the brake oil pressure of the rear wheels Wrff and Wrr remains low, and the slip ratio is reduced. This allows rear wheel Wri! , the interference from Wrr to the front wheel W'1, Wrr is suppressed to a small level, and a good anti-lock system t: [[l is performed. By the way, during braking, the road surface rays change and the adhesion coefficient becomes large. In this case, the rear wheel Wrff,
If the Wrr play-F oil pressure is kept low, even though there is no functional problem, the brake pressure of the rear wheels Wrl and Wrr will become too low, and the front wheels Wfffi,
Since 91j of Wrr becomes larger, the front wheel Wfl! , Wf
A disadvantage arises from the viewpoint of the negative 111 reduction of r. However, in a), the pressure increase prevention amount after pressure reduction is 0.5~
Since there is a constant i of 1 ull per 1 culm degree, the front wheel Wr1.
It is possible to achieve f'l river light use of Wfr. Furthermore, since the 11;1 transport control unit 9a individually controls the 11; single-wheel modulators Miff and Mfr, the effect of control+J+distance and running stability of 1: can be obtained. !
l-straw, front wheel Wre, Wfr and 7&l・12W
r e. In the four-wheel drive type, where the Wrr is almost rigidly connected, the front and
lQW (7!, '+l/ f r control is rear wheel Wr
i! , Wrr, so the front wheel speed,
The modulator Mfl, M(r
In the case of High Select 1 and 2 controlling simultaneously the front wheels W(1!, W(r)), there is a possibility that the front wheels W(1!, e
. When the vehicle reaches Wrr, the rear wheels Wrn and Wrr slip, resulting in poor running stability. Furthermore, it is obvious that the braking distance will be extended if the front wheels W (1, Wfr) with a high load distribution are used and a low selection method is adopted in which both the front wheels (FBrjLBfr) are simultaneously controlled according to the low-speed side III transmission speed. In the second embodiment, the rear wheel side modulator M “CMrr
were controlled simultaneously using the low selection method, but
((The control may be performed separately for υ. Also, the delay circuit 24 may be interposed between the second comparison circuit 14 and the OR gate 17. According to the present invention, as shown in the effect of the C1 invention, Apply the brakes to each wheel individually, and avoid increasing the hydraulic pressure until a certain period of time has elapsed after the rear wheels are no longer in danger of locking. 7, it is possible to reduce the slip rate of the rear wheels and perform good anti-l-17 control, thereby reducing the burden on the front wheel plate.

[Brief explanation of 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 brake system, and FIG. 4.1 is a schematic diagram of the rear wheel control section, and FIG. 5 is a characteristic diagram of the delay circuit. 1...1-Luke transmission i 41. Viscose clutch as 'j, 7... Brake hydraulic system, 9... Anti-lock control device, 9a... Front wheel control unit, 9b...
Rear wheel control section, Af l, Af r, ArI! , Arr-
Axle, Br1, Brr...brake, P...power unit, Wf l! , W[r, Wr R,Wr
r-...Wheel time Applicant: Book 111 Gikenchogyo Co., Ltd. Representative Patent Attorney Ochiai

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 the four-wheel drive vehicle is configured to avoid an increase in brake hydraulic pressure until a certain period of time has elapsed.