JPS6150858A - Brake operating method - Google Patents

Abstract

PURPOSE:To reduce a degree of fluctuations in a car body at both forward and backward movements, by controlling brake feeding pressure to the rear-wheel side to be reduced in time of a car forward movement and also reduce the pressure to the front-wheel side in time of a car backward movement. CONSTITUTION:In time of a car forward movement, if braking takes place, pressure in a master cylinder is fed to each of front and rear wheel cylinders via pressure reducing valves 26, 31 and 71, 74. In time of it forward movement, a valve gear 76 is opened and since the master cylinder pressure is also fed to a control chamber 27, a main piston 20 is not moved. Therefore, the pressure reducing valve at the front-wheel side is no longer operated and thereby the rear- wheel side alone is controlled to reduce its pressure. At braking in time of a car backward movement, a coil 37 is excited and the valve gear 76 is closed. With this constitution, the master cylinder pressure is not transmitted to the control chamber 27 so that the main piston 20 is made movable, thus pressure at the front-wheel side is controlled for pressure reduction. And, fluid pressure in a small diametral hole 60 is zero whereby the rear-wheel side comes high in its reduction starting pressure so that no reduction control takes place usually.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a brake operation method for a vehicle, etc.

[Conventional technology and problems]

Conventionally, in vehicles, etc., the pressure of brake pressure fluid supplied to the front wheel side brake application device is not reduced during forward movement or backward movement, and is supplied as is.

By the way, in a vehicle that uses 2L type drum brakes for the front wheels, if the braking pressure obtained by the front wheels when moving forward is the same as the braking force obtained from the front wheels when reversing, then Due to the structure of this type, the former is probably larger. Therefore, the nose dive phenomenon that occurs due to the load shift caused by applying the brakes when moving forward, and the rearward nose dive (tentatively referred to as tail dive) phenomenon that occurs when reversing, the former is thicker (and the latter is thicker). However, when changing the front wheel brake system from a 2L type drum brake to a disc brake, the braking force obtained by the disc brake itself is the same when moving forward and when reversing. There is no difference in the above phenomena 2
The tail dive phenomenon becomes considerably larger than when all L-type drum brakes are used.

For this reason, the rear wheel suspension system must be large and high-performance, capable of supporting a larger load;
It becomes necessary to change the wheel suspension system itself to completely prevent the above-mentioned nose dive and rurl dive.

As a result, the entire suspension system for the front and rear wheels would have to be changed, but by changing the brake type for the front wheels, the entire vehicle would have to be changed. Since it is only used to cope with the phenomenon that occurs when reversing, it not only becomes extremely inefficient, but also causes various problems such as an increase in the weight of the vehicle and a decrease in fuel consumption.

In addition, even if the player model is not changed, if relatively strong braking is applied when reversing, the braking force obtained by the front wheels will be large, causing a tail dive phenomenon, which will cause an unnecessarily large load to be applied to the suspension system. This leads to problems such as decreased durability and damage.

[Object and structure of the invention]

The present invention has been made in view of the above problems, and an object of the present invention is to provide a brake operation method that reduces fluctuations in the vehicle body due to brake operation when reversing. According to the invention, this purpose is to supply brake pressure fluid from at least one pressure source to the brake actuator provided on the front wheels and the brake 1' provided on the rear wheels by operation of the driver. 2. When the vehicle moves forward, at least 9τ of the rear vehicle is applied.
] When the vehicle, etc. is moving backward, the supply pressure to at least the front wheels is controlled to be reduced, and when the vehicle, etc. is moving forward, the supply pressure to the rear wheels is reduced to the front wheel side. This is achieved by a brake actuation method, K, in which the pressure is lower than the supply pressure to the vehicle, and vice versa when reversing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a hydraulic pressure control valve according to an embodiment of the brake operation method of the present invention will be described with reference to the drawings.

In the figure, the hydraulic control valve is indicated as a whole (ll,
A first stepped hole (3) extending left and right is formed in the middle portion of the valve body (2), and a second stepped hole (4) similarly extending left and right is formed in the lower portion. First stage hole (3)
and the left y of the second stepped hole (4)! @Opening with lid plate (5)=
It is covered with The cover plate (5) is fixed to the valve body (2) with bolts, although not shown. In addition, the first stepped hole (3)
The right end opening is the first with the metal seal ring (8) intervening entirely.
The lid member (6) is screwed onto the valve body (2) to cover it. The right end opening of the second stepped hole (4) is covered by fully attaching the seal ring (9) to the tip and screwing the second lid member (7) onto the valve body (2).

On the back side of the valve body (2), as shown by the dotted line, a one-star cylinder connection hole αq is formed to communicate with the first stepped hole (3), and the right upper protruding portion (2a) of the valve body (2) ), the front wheel cylinder connection hole qυ is the first step hole (
3). The mask cylinder connection hole 00 and the front wheel cylinder connection hole aυ are connected to the master ring and the front wheel cylinder through piping (not shown), respectively.

The side piston (
113 is inserted, and its large diameter part is the cup seal a″I)
When fully installed, it fits evenly into the second hole Q. In addition, the spring bearing of the secondary piston (4) is biased to the right by a spring (T) stretched between the ring α9 and the cover plate (5), and the second hole αυ third hole (2) It is in contact with the left end of the main piston (4) which is inserted through the fourth hole. This left end (211 is a cup seal at-fitted and fitted into the second hole (G) 9, and the right end with a larger diameter than the straight end CD is a cag seal R24t-fitted and fitted into the third hole 125
1 is fitted. A cylindrical tip member 4 is integrally fixed to the right end of the main piston (E), and when the brake shown in the figure is not in operation, the urging force of the bouncing rice is transferred to the sub piston (G). Through the support is the tip of the main piston ■,
That is, the tip member 4 is in contact with the inner end surface of the first lid member (6). In addition, between the cup seal (17) attached to the sub-piston Qfp and the cup seal attached to the main piston (1), there is a valve device (7 et Through the fourth hole part (
A control royal family (n) is defined that can communicate with the control royal family (n).

A through hole is formed in the middle part of the main piston (4) in the radial direction, and an auxiliary inner hole (2) is formed in the axial direction in communication with the through hole. The right canine diameter hole part of this stepped inner hole ■ and the tip member c
A valve member 31) is disposed across the inner hole 261, and is biased to the right by the valve spring and abuts against the inner end surface of the first lid member (6). Further, the large diameter portion of the valve member 6υ faces the valve seat 03 formed as the inner hole edge of the tip member 4, and although it is separated from the μ valve chamber C3 in the illustrated state, it is seated on this when the brake is applied. It is possible. A groove C slope is formed in the radial direction on the end face of the tip member (c), and in the state shown in the figure, the mask cylinder pressure type ση defined around the middle part of the main piston (1) is connected to the radial passage (towards ),
It communicates with the front wheel cylinder connection hole Ql) via the stepped inner hole 6G groove (B).

In the second step hole (4), a coil (3D) is wound around the first hole and a nine electromagnetic core is molded and fixed with resin. The lead wire 3g is led out from the opening (5a) of the cover plate (5).The first hole (to) further includes an annular member t4f) equipped with a seal ring t43 +4υ on the inner and outer periphery. The reduced diameter portion of the electromagnet core is fitted into the center hole of this annular member +4CI. 1st hole (to)
A control piston (4) is slidably fitted into the second hole on the right, which has a smaller diameter, and is stretched between the ring (7) and the annular member (4 (1)). It is biased to the right by the spring (9) and comes into contact with the right step of the second hole.The shaft at the tip of the control piston The small third hole (c) is inserted through the right stepped hole 61).

The service hole portion 5D functions as a valve chamber, and is arranged so as to abut the valve ball (41 is the shaft portion t47 of the control piston I). The valve ball (biased to the left by the 41U valve spring ■) can come into contact with the step formed between the stepped hole section 61 and the third hole section, which serves as the valve seat sigma. . The lead wire field of the coil port mentioned above is connected to this hydraulic pressure control valve (IJ't) even though it is not shown in the figure.
- It is connected to a switch that detects the backward movement of the equipped vehicle, and is configured as a VC so that when this switch is closed, three coils R are energized. Control piston t441H
It is made of a magnetic material, and when the coil l37) is excited, the control piston is attracted and driven to the left by the magnetic flux flowing through the electromagnetic core (g) against the spring force of the spring t4G. As a result, the valve ball (4!1) that is in contact with the control piston (the shaft (47)) is also moved to the left by the spring force of the valve valve t5G, and comes into contact with the valve seat (19). ing.

The valve ball (49), the valve spring 150, and the valve seat (4) connect the control crown (2) on the left side of the main piston rod in the first stepped hole (3) mentioned above, and the fourth hole on the right side. A valve i position +7119 is installed for all communication and non-communication between the fourth hole portion (28) and the stepped hole portion I of the second stepped hole (4) in the illustrated state.
5+) and the third hole f4s in the second stepped hole (4) and the shaft of the control piston (4・υ) (
The gap between the control piston W4 and the first stage Hole (3
)'s 4th Kobeta and the Control Royal Palace (3) are connected. That is, the valve device 17[9 is in an open state. When the coil diagram is energized, the valve ball (fourth valve) seats on the valve seat σIK, cutting off communication between the fourth hole and the control pressure chamber. In other words, the valve is in a closed state.

A third stepped hole 1541 is formed in the upper left side part (2b) of the valve body (2) in the vertical direction, and the upper opening end of the hole 1541 is screwed with a lid member fitted with a seal ring 6 (1g). In addition, a master cylinder connection hole mark and a rear wheel cylinder connection hole (2) are formed laterally in communication with the third stepped hole 154).

Each of these is connected to a mask ring and a wheel cylinder of the rear wheel by means of pipes (not shown).

A piston mark is slidably fitted into the third stepped hole 54), and the lower small diameter portion (6 points are the small diameter hole portion 1 of the stepped hole a).
It is resealed and fitted with 6GK seal ring t611. The small diameter hole section a communicates with the above-mentioned control chamber. The upper small-diameter portion of the piston example fits into the small-diameter portion of a stepped recess (round) formed in the lid member 69, and is sealed by a cutter can attached to the large-diameter portion of the recess. As a result, six air chambers (6 air chambers) are formed between the upper small diameter portion Is of the piston 69 and the lid member 59. It is enlarged by the hole side.

Stepped piston CJ expansion spring receiver (69 and its first large diameter part σ
is urged downward by a spring σα stretched between
It abuts against a ring-shaped valve comb συ attached to the stepped portion of the stepped hole 54. The valve rubber συ has a plurality of protrusions (71aX7ib) f: on the upper and lower surfaces, respectively;
) is in contact with the first large diameter section of the piston 61, and the lower projection (71h) is in contact with the stepped portion of the stepped hole 54. That is, a gap is formed by these protrusions (71a871b), and under normal conditions, the mask cylinder royal Q3Q around the upper small diameter part S of the piston 61 is connected to the wheel around the second large diameter part σ20 of the piston (59). It is communicated with the cylinder pressure chamber 1811.The first large diameter portion σ~ and the second large diameter portion σ2
The diameter of the small diameter part σ between the valve rubber συ is sufficiently smaller than the diameter of the center hole of the valve rubber συ, but the diameter of the center hole of the diameter iron valve rubber συ of the second large diameter part @ is sufficiently larger. It can be seated on a rubber circle. The mask cylinder pressure chamber is always in communication with the mask cylinder connection hole 6D, and the wheel cylinder pressure chamber is always in communication with the rear wheel cylinder hole 68 through the through hole.

The hydraulic pressure control valve (1) according to the embodiment of the present invention is constructed as described above, and its operation, effects, etc. will be explained below.

First, the case where the brake is applied during forward movement will be explained. When the driver steps on the brake pedal (not shown), fluid pressure from the mask cylinder is applied to the master cylinder connection hole α0157.
1. The chamber pressure to the connection hole 00 is transferred from the mask cylinder royal house to the front wheel cylinder connection hole α through the axially stepped hole ■ and the fourth hole l of the radial hole of the main piston (to). Transmitted and play I to the front wheel? Spend money. This hydraulic pressure is further applied to the passage Fi2 and the valve device σ which is open.
The control pressure is also transmitted to the constant amount of control pressure through the passage (c) and passage 153 of the 01 control piston (44).

Now, the cross-sectional area of the right end θ of the main piston rod is the metal AI, the left end +
The cross-sectional area of 211 is t-A* (<A,), the spring blade of the spring (to) is f, and the force to the right that directly acts on the main piston (4) is F and the force directly acting on the sub-piston (7) is K. If the force to the right is defined as the hydraulic pressure of the B1 master cylinder royal σ force=a-PM, and the hydraulic pressure of the fourth hole (end) and the control pressure chamber fpw, the following relationship is obtained.

F, == AIFW + (AI-AI) PM-8, P
W=(A,-A,)・(PM-pw) F□=f-A,・pw Then, the main piston (A) has pu, pw, force l; sea limit 5F, =O, so it is completely At the same time, the sub-piston QI19 will not move, and at pressures below f/A, it will press the main piston gJft to the right, and when this pressure is exceeded, it will separate from the main piston (a) and move to the left independently. It's a trap to do that. Therefore, from the moment the brake is applied, the pressure in the mask cylinder royal ση and the fourth hole (end) increase equally, so even if the secondary piston qQ moves in response to the pressure increase, the main piston pressure μ It does not move and pressure reduction control is not performed. That is, the hydraulic pressure from the mask cylinder is supplied to the front wheel cylinder without being reduced in any way, and the brake is applied in the same way as in the conventional case.

On the other hand, the hydraulic pressure to the connection hole 6η is the master cylinder pressure chamber, the valve rubber σD, and the piston 6! The pressure is transmitted to the rear wheel cylinder connection hole (G) through the gap between J and J, the wheel cylinder pressure chamber, and the through hole. This applies the brakes to the rear wheels as well, but now the lower small diameter portion of the piston 51 sa (7) f! The area fT is 81, the seating area of the second large diameter part σ for the valve rubber συ is f:S, the cross-sectional area of the upper small diameter part ts, the spring force of the spring qG is f', the master cylinder royal field is , and the hydraulic pressure in the wheel cylinder pressure chamber [F]υ wot', the piston 69 (t-
upward pressing force F1′ and downward pressing force F,
(is expressed as follows. Note that the hydraulic pressure in the mask cylinder pressure chamber is equal to the hydraulic pressure in the master cylinder g on the front wheel side mentioned above, pM = pM', and therefore the small diameter hole i6 that communicates with the control chamber - The hydraulic pressure of is PM l.

Fl' = SIPM' + (St-8,) PW'
and Ft' = (Ss - Ss) PM' +
Until t', the wheel cylinder hydraulic pressure Pw' rises equally upward by f', but when it exceeds -removal, the piston 15! I moves upward, and its second large diameter portion σZ seats on the valve rubber (731,
Master cylinder royal □□□ and wheel cylinder royal 18
Communication with 1) will be cut off. Thereafter, as the hydraulic pressure PM l in the master/linda hydraulic pressure chamber ω increases, seating and disengagement are repeated, and known pressure reduction control is performed on the rear wheels.

Hydraulic pressure for rear wheel cylinder
The pressure is reduced at a rate of ``'(<1) and the cals are increased S, -S.

go.

Next, a case will be explained in which the brakes are applied when the vehicle is backed up.

When the vehicle starts to back up, this is detected by a switch (not shown) and the switch is closed. As a result, the coil 13
7) is energized and the control piston is suction driven to the left. The valve ball a is seated on the valve seat l'79, and the valve device 4 is closed. The first stage hole ( 3) The 4th hole C second and the control royal □□□ are out of communication. When the driver depresses the brake pedal in this state, the fluid pressure from the mask cylinder is transferred to the 4th hole (to). However, the force F' pushing the main piston clO'e leftward is as follows.

F'= A+pw-(A,-A, ) PIe fF'
is pea, increases with PM = FW), p
w Air Al-Al x pM+Eng A, A.

When K is reached, the main piston (1) moves to the left, and the valve member CD is seated on the valve seat Ga [. After that, the hydraulic pressure pv of the front wheel cylinder decreases and increases at a rate of 2~22~=(kl) (pressure reduction control starting point I) M
= Mutual).

On the other hand, on the rear wheel cylinder side, the small diameter hole 6CI
Since the hydraulic pressure of is zero, the force FI' that presses the entire piston upward is F, '= (S, -3,) pw', and the cam ' that presses downward is F weight '=(5t-8,) Pl<'+f', so if the master cylinder's hydraulic pressure PM' exceeds s, -8,'', full pressure reduction control will be performed, but the above-mentioned pressure reduction control start point during forward movement will be S'=Compared to the above, the decompression side S that will die during this retreat
.

A much larger tentative S at the starting point pM'= f'-
,-S.

le (',' S, middle S,). S, ) S, O-i combination
Since h normally vc Pg'>Fl', pressure reduction control is not performed no matter how much the mask cylinder hydraulic pressure T' increases. In addition, the pressure reduction f! tlJ @Starting point PM= Much larger than A than Engineering.

As a result, when the vehicle is moving backwards, the pressure supplied to the front wheels becomes smaller than the pressure supplied to the rear wheels. Further, when the vehicle is moving forward, the pressure reduction control is not performed on the front wheels as described in 7t above, so the above relationship is reversed.

In this manner, the braking force applied to the front wheels when the brakes are applied when the vehicle is moving backwards is reduced, and the load shift can be further reduced compared to the conventional method. In particular, when changing the front wheels from 2L type drum brakes to disc brakes, the load shift was extremely large when reversing, which caused problems with the durability of the suspension system for the front and rear wheels. Example prevents extreme load transfer,
It is possible to capture money using a hanging device. Furthermore, since the braking force applied to the rear wheels is reduced when the vehicle moves forward, the tendency of the rear wheels to lock can be suppressed.

Although the embodiments of the present invention have been described above, the present invention is of course not limited thereto (and various modifications can be made based on the technical idea of the present invention).

For example, in the above embodiment, the coil o'off: is energized by the switch l/C that detects the backward movement of the vehicle, but instead of this, the switch is turned on and off in conjunction with gear change for backing up. The coil may be energized or de-energized. Or 1! Magnet core (g), coil Ω
η etc. may be omitted and the valve device rle may be opened and closed directly in conjunction with gear switching.

Furthermore, in the above embodiment, the small diameter portion 6316 of the piston 6!1
In 5), the cross-sectional area of the metal is made equal to 0.05 mm, and when the vehicle is moving backwards, the depressurization control start point is made very high, so that depressurization control is not actually performed. Electromagnet core (to), coil C3
7) A structure corresponding to a valve device σe, etc. is installed in parallel on the bypass path between the mask cylinder pressure chamber and the wheel cylinder royal g3IJ, and when the vehicle is backing up, the valve device is opened to reduce the hydraulic pressure in the master cylinder pressure chamber. It may be possible to bypass the wheel cylinder royal autopsy. When moving forward, the valve device is closed and the pressure reduction control described above is performed, but since the forward time is much longer than the backward time, the valve device is fully opened by excitation of the coil, and is normally closed. It is preferable to set it as a structure.

〔Effect of the invention〕

As described above, according to the brake operation method of the present invention,
It is possible to appropriately distribute the brake force when moving forward while reducing fluctuations in the vehicle body due to brake operation when reversing, and the load on the suspension system can be reduced.

[Brief explanation of the drawing]

The figure is a sectional side view of a hydraulic pressure control valve according to an embodiment of the brake operation method of the present invention. In addition, in the figure,

Claims (1)

[Claims] Brake operation that applies brakes to a vehicle, etc. by supplying brake pressure fluid from at least one pressure source to a brake applicator provided on the front wheels and a brake applicator provided on the rear wheels by a driver's operation. In this method, when the vehicle, etc. is moving forward, the supply pressure to at least the rear wheels is switched to reduce the pressure, and when the vehicle, etc. is moving backward, the supply pressure is switched to at least the front wheels. A brake operation method in which the pressure supplied to the rear wheels is lower than the pressure supplied to the front wheels, and vice versa when reversing.