JPH11263206A - Braking control device for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking control device for an automobile which can mechanically maintain the loading condition at the starting of braking and suppress the reduction of distributed oil pressure. SOLUTION: A braking control device body 19 is provided which reduces the oil pressure from a master cylinder in accordance with the suspension stroke of a rear axle 12 and then transmits it to a rear brake. A suspension detecting portion of the displacement amount 20 of the braking control device body 19 and oppositely facing reaction bodies 21 provided through a repulsing means 22 in the suspension detecting portion of the displacement amount 20 are slidably fitted to a sliding shaft 17 arranged in the stroke direction of the body 14. There is also provided a means 51 for foxing the reaction bodies 21 to the sliding shaft 17 at the braking. The braking control device body 19 and the sliding shaft 17 are mounted either one of the side of the body or the rear axle and a stopping member 18 for stopping the reaction bodies 21 is mounted to the other one of the side of the body or the rear axle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle brake control device, and more particularly to a vehicle brake control device provided with a load detection type control valve capable of adjusting the degree of use of a rear wheel brake in accordance with a load amount.

[0002]

2. Description of the Related Art A brake system of an automobile generates a hydraulic pressure in a master cylinder by depressing a brake pedal, and applies the hydraulic pressure to a wheel cylinder of each wheel to press a brake shoe against a brake disk or a brake drum. Power is being generated. Among various braking devices, in order to obtain a stable braking force,
Some vehicles have a braking control device that adjusts the oil pressure from the master cylinder in accordance with the magnitude of the braking force and the amount of luggage loaded on the vehicle, and then supplies the hydraulic pressure to the wheel cylinders of the front and rear wheels.

FIG. 8 shows a ratio of a braking force acting on a front wheel and a rear wheel of an automobile equipped with the above-mentioned braking control device. The light load is small when the load is small and the constant load when the load is loaded to an allowable amount. This represents the ideal allocation, target allocation, and actual allocation at the time. In FIG. 8, when the ideal front and rear wheel braking force distribution shown by the dashed line is viewed, in both light loading and constant loading, when the braking force is small, the rear wheel braking force is increased to increase the vehicle body weight. It is understood that it is desirable to increase the ratio of the front wheel braking force at which a strong braking force can be obtained as the braking force increases while stabilizing the braking force. In an actual braking device, it is difficult to gradually increase the braking ratio of the front wheels. Therefore, as shown by the thick line in FIG. After the braking force exceeds a certain level, braking is performed at a braking force ratio obtained by reducing the braking force ratio of the rear wheels, and a target distribution similar to an ideal distribution is set. At the time of braking, since the rear wheels are easily locked, the rear wheel braking force cannot be set higher than the ideal distribution. Further, whether or not the rear wheel locks is greatly affected by the magnitude of the load acting on the rear wheel. Therefore, the load supported by the rear wheels is increased by the load of the heavy load in the rear half of the vehicle body during the constant loading as compared with the light loading, and it is difficult to lock the rear wheels, so that the rear wheel braking force can be increased.

FIG. 9 shows a conventionally proposed braking control apparatus, which can adjust the hydraulic pressure supplied to the wheel cylinders of the rear wheels according to the braking force and the load. A control valve 2 of a load detection type is fixed to a bracket 1 attached to a vehicle body, and one end of a lever 3 is rotatably supported. An adjustment spring 4 is bridged between the control valve 2 and the lever 3 to apply tension in a direction of pulling each other. A plunger 5 that slides on the control valve 2 is in contact with the side of the lever 3 between the rotation shaft and the locking portion of the adjustment spring 4.
The other end of the lever 3 is locked with a main spring 6 to which a tension acts in a direction opposite to that of the adjustment spring 4. The tip of the main spring 6 is attached to a bracket 8 that bundles a leaf spring 7 of a rear wheel suspension. It is connected.
Therefore, when luggage is loaded on the vehicle, the rear wheel suspension device sinks in accordance with the load amount, and the main spring 6 is pulled with the vertical movement, and the force acting on the lever 3 changes. Will do. Looking at the force acting on the lever 3 when the rear wheel suspension moves up and down, the difference between the moment due to the tension of the adjusting spring 4 and the moment due to the tension of the main spring 6 that changes due to the vertical movement of the rear wheel suspension is represented by A pressing force acts on the plunger 5 in accordance with the load amount. Inside the control valve 2, the hydraulic pressure is appropriately reduced according to the magnitude of the hydraulic pressure passing through the inlet pipe 9 from the master cylinder and the magnitude of the pressing force acting on the plunger 5, and the hydraulic pressure is reduced from the outlet pipe 10 to It leads to the wheel cylinder of the rear wheel.

In the conventional brake control device shown in FIG. 9, the amount of load is detected by measuring the amount of vertical movement of the rear wheel suspension.

[0006]

However, the rear wheel suspension device moves up and down other than when the load capacity changes. In particular, since the center of gravity moves forward at the start of braking, the load acting on the rear wheels is reduced, the rear wheel suspension device is extended, and the state is the same as when the load is small. Therefore, at the time of actual braking, unlike the target distribution in FIG. 8, braking is performed at a ratio based on the actual distribution indicated by the thin line, and there is a problem that the rear wheel braking force is smaller than the target distribution. In order to solve this problem, it is conceivable to determine the target distribution in anticipation of the movement of the center of gravity accompanying the start of braking. , It is difficult to determine an appropriate target allocation. Also, in order to avoid rear wheel lock, it is necessary to lower the rear wheel braking force so that the rear wheel does not lock at any loading position and height of the center of gravity, so depending on the loading position and height of the center of gravity The target distribution in which the rear wheel braking force is reduced more than necessary is set.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a brake control apparatus for an automobile which can mechanically hold a loaded state at the start of braking and can suppress a decrease in hydraulic pressure distribution.

[0008]

In order to achieve the above object, the present invention comprises a brake control device main body which reduces the hydraulic pressure from a master cylinder in accordance with a suspension stroke of a rear axle and transmits the reduced pressure to a rear wheel brake. A suspension displacement amount detection unit of the braking control device main body, and a responsive body opposed to the suspension displacement amount detection unit via a repelling means, which is slidable with respect to a sliding shaft disposed in a stroke direction of the vehicle body. Means for fixing the responsive body to the sliding shaft at the position where the vehicle body sinks during braking, and mounting the brake control device main body and the sliding shaft on either the vehicle body side or the rear axle side And a locking member for locking the responsive body is mounted on either the vehicle body side or the rear axle side. According to the present invention, the dimensions of the suspension displacement detection unit and the rear axle do not change even if the center of gravity of the vehicle moves forward at the start of braking. Therefore,
Since the main body of the braking control device does not excessively reduce the braking force of the rear wheel due to the posture change during braking, a sufficient braking force is exerted also on the rear wheel, and stable braking can be obtained.

[0009]

1 (a) and 1 (b) show the entire structure of an automobile provided with a braking control device, and FIG. 1 (a) shows a state in which a light load is not braked, and FIG. 1 (b) Indicates a state at the time of constant load non-braking. 2 to 5 are partial cross-sectional views showing a vehicle brake control device to which the present invention is applied. FIG. 2 shows a state in which the vehicle is lightly loaded and no braking is performed, and FIG. 4 shows a state at the start of braking, and FIG. 5 shows a state during braking.

In FIG. 1 to FIG. 5, a rear axle 12 is mounted inside an axle case 11 through a bearing (not shown).
Is rotatably mounted. Further, the axle case 11 is attached to the vehicle body 14 by the suspension arm 13.
The suspension spring 15 repels between the axle case 11 and the vehicle body 14 to support the weight of the vehicle body. The upper end of a sliding shaft 17 is rotatably supported on the vehicle body 14 by a pin 16.
7 has a lever 1 provided on the axle case 11.
8 is inserted through the hole 18a. The sliding shaft 17 is attached to the vehicle body 14 so as to be slidable with respect to the lever 18 and to allow a slight inclination. The lever 18 is a locking member that locks a downward movement of a response body 21 described later, and is attached to the axle case 11 by welding, bolting, or the like. This lever 18 is axle case 1
It is also possible to integrally mold it into a part of one.

A brake control device main body 19 is mounted on the lower surface of the vehicle body 14 via a rubber damper or the like (not shown). A tip of a detection lever 20 as a suspension displacement detecting portion of the brake control device main body 19 is mounted. An annular portion 20a is slidably mounted in the middle of the sliding shaft 17. A responsive body 21 is disposed between the distal end annular portion 20a of the detection lever 20 and the lever 18, and the responsive body 21 is opposed to the distal end annular portion 20a of the detection lever 20 via a spring 22. The response body 21 is slidably and loosely fitted on the slide shaft 17 through the insertion hole 21a, and the lower end thereof is connected to the lever 1.
8 locked. The sliding shaft 17 is provided with an uneven engaging portion 23 from an intermediate position to a lower position. A stopper 24 is attached to a lower end of the sliding shaft 17 so that the lever 18 slides. It is prevented from coming off the shaft 17.

FIG. 6 shows the internal structure of the brake control device main body 19. The main body 19 of the braking control device includes the control valve 2.
5 is housed, and a boot 27 that houses a pivot 20c of the base end 20b of the detection lever 20. A cylinder hole 28 is drilled upward in the case body 26, and a valve guide 29, a piston 30, an adjustment spring 3
1. The spring holder 32 and the seal holder 33 are inserted, and are locked by the snap ring 34 so as not to fall out of the cylinder hole 28. The lower end of the piston 30 is in contact with the base end portion 20b of the detection lever 20, and the detection lever 2 which responds when the vehicle body 14 sinks during braking.
It operates by the movement of 0. A flange 35 is provided at an intermediate portion of the piston 30, and a seal 38 that divides into a first chamber 36 below the cylinder hole 28 and a second chamber 37 above is locked. Adjusting spring 31
5 and compressed between the spring holder 32,
The piston 30 is urged upward. Seal holder 33
Penetrates the piston 30 at the center thereof, and holds oil seals at the inner diameter portion and the outer diameter portion, respectively, to keep the cylinder hole 28 and the piston 30 liquid-tight. At the center of the piston 30, an adjustment passage 39 connecting the first chamber 36 and the second chamber 37 is formed, and a check valve including a ball 40 and a spring 41 is provided at an intermediate portion of the adjustment passage 39. .

The center of the valve guide 29 forms a downwardly convex portion, and the upper end of the piston 30 is
, The convex portion pushes the ball 40 to open the check valve. Further, the piston 30 is provided with a groove 42 so as to secure an oil passage even when the piston 30 contacts the valve guide 29. An inlet pipe 43 extending from the master cylinder is fixed to the case main body 26 by a flare nut 44, and a hydraulic passage from the master cylinder is connected to the first chamber 36 via an inlet passage 45 formed in the case main body 26. You. Similarly, an outlet pipe 46 connected to a wheel cylinder of a rear wheel is fixed to the case main body 26 by a flare nut 47, and a hydraulic passage is connected to the second chamber 37 via an outlet passage 48.

As shown in FIG. 7, the responder 21 has a slide pin cylinder hole 50 formed in a direction perpendicular to the insertion hole 21a from the outer wall 49a of the case 49. Slide pin 5
1 is housed. Slide pin cylinder hole 50
, An inlet pipe 52 is fixed by a flare nut 53, and hydraulic pressure from a master cylinder is applied to a hydraulic passage 54.
And acts on the slide pin cylinder hole 50. The slide pin cylinder hole 50 has a built-in spring 55 for urging the slide pin 51 away from the concave-convex engaging portion 23 of the slide shaft 17.
The slide pin 51 slides in the slide pin cylinder hole 50 by the hydraulic pressure from the master cylinder, and its tip engages with the uneven engagement portion 23 of the slide shaft 17 against the urging force of the spring 55. Is what you do.

The operation of the embodiment shown in FIGS. 1 to 7 will be described below in detail. The piston 30 has a force for pushing the piston 30 upward, a force by hydraulic pressure guided from the master cylinder, and an adjusting spring 31.
There is a force that pushes up the piston 30 and a force of the spring 22 that acts on the detection lever 20 as the suspension displacement amount detection unit. Further, as the force for pushing the piston 30 downward, the force of the hydraulic pressure from the master cylinder acting on the second chamber 37 via the adjustment passage 39 and the convex portion of the valve guide 29 push the spring 41 of the check valve downward. Force acts. However, the force by which the valve guide 29 pushes the spring 41 of the check valve downward is much smaller than the other forces, and therefore will not be described below. Piston 3
0, the hydraulic pressure from the master cylinder acts from both upper and lower directions. However, since the piston 30 penetrates the first chamber 36, the area d of the piston penetration portion is smaller than that of the second chamber 37.
When the hydraulic pressure of the master cylinder is subtracted, only the pressure corresponding to the area d of the piston penetration portion acts as a downward force.

When the hydraulic pressure from the master cylinder is weak, the hydraulic pressure is applied to the inlet pipe 43 and the inlet passage 4.
5, first chamber 36, adjustment passage 39, check valve, groove 4
2. Reach the wheel cylinder of each rear wheel via the second chamber 37, the outlet passage 48, and the outlet pipe 46, and operate the brake. In this state, the piston 3
Since the hydraulic pressure acting as a force for depressing 0 is smaller than the sum of the loads of the adjusting spring 31 and the spring 22, the piston 30 does not move and the hydraulic pressure from the master cylinder is applied to the wheel cylinders of each rear wheel without being reduced. Be guided.

When the hydraulic pressure from the master cylinder increases, the force acting downward on the piston 30 increases,
The piston moves below the sum of the loads of the adjusting spring 31 and the spring 22, that is, the direction in which the detection lever 20 is pushed down. Then, until now, ball 4
Since the valve guide 29, which has pushed 0 downward, separates from the ball 40, the ball 40 is pushed upward by the spring 41, abuts the valve seat 30a of the piston, and shuts off between the adjustment passage 39 and the second chamber 37. . Thus, the transmission of the hydraulic pressure to the rear wheel cylinder is stopped.
When the oil pressure from the master cylinder further increases, only the oil pressure in the first chamber 36 rises, so that the piston 30 moves upward due to the oil pressure difference between the first chamber 36 and the second chamber 37. Then, the valve guide 29 pushes down the ball 40, the passage communicates, and the hydraulic pressure in the first chamber 36 and the hydraulic pressure in the second chamber 37 become the same. Therefore, when the hydraulic pressure from the master cylinder gradually increases, the piston 30 finely moves up and down to adjust the hydraulic pressure for the reasons described above, and the reduced hydraulic pressure is guided from the second chamber 37 to the wheel cylinders of each rear wheel.

When a load is loaded on an automobile, the suspension spring 15 is compressed by the weight of the load, and the vehicle body 14 relatively sinks as shown in FIG. Then, as shown in FIG.
The sliding shaft 17 is lowered together with the vehicle body 14.
When the brake control device main body 19 is pushed downward,
The spring 22 spanned between the lever 18 that moves up and down together with the rear axle 12 and the detection lever 20 attached to the brake control device main body 19 is compressed, and the detection lever 20 serving as the suspension displacement detection unit is upwardly moved. The turning force acts more. Therefore, the detection lever 20 can transmit the resilient force of the spring 22 that changes according to the displacement amount of the suspension to the piston 30.

As described above, the piston 30 starts operating when the hydraulic force acting on the area d of the piston penetration exceeds the load acting on the piston 30 by the adjusting spring 31 and the spring 22. Therefore, when the weight of the luggage loaded in the automobile increases, the force of the spring 22 pushing up the piston 30 via the detection lever 20 increases, and the magnitude of the hydraulic pressure at which the piston 30 starts operating increases. Therefore, when the luggage is loaded to the maximum, the ratio of the rear wheel braking force is higher than the target distribution during light loading as shown in the target distribution during constant loading in FIG.

Next, looking at the operation at the start of braking, the hydraulic pressure from the master cylinder is guided to the first chamber 36 and acts on the piston 30, and at the same time, through the hydraulic passage 54, the slide pin in the slide pin cylinder hole 50. Acts on 51. Since the initial load and the spring constant of the spring 55 acting on the slide pin 51 are low, the slide pin 51
It moves toward the sliding shaft 17 at the same time as the hydraulic pressure acts. Then, the tip of the slide pin 51 engages with the engaging portion 23 of the sliding shaft 17 that moves up and down together with the vehicle body 14, and the responsive body 21 is fixed to the sliding shaft 17 at the same time as the start of braking. Since the slide pin 51 is operated by the braking oil pressure, it is advantageous in reliability. With the start of braking, the center of gravity moves forward, the suspension spring 15 extends, and the rear of the vehicle body is lifted up. However, since the responding body 21 is fixed at that position (see FIG. 5), the tip end of the detection lever 20 is also annular during braking. The distance between the portion 20a and the response body 21 does not change,
The force applied by the spring 22 to the detection lever 20 and the force applied to the piston 30 do not change. Since the spring force of the spring 22 is held even when the vehicle body 14 is displaced during braking, a stable braking force can be secured even when the posture changes during braking. The vehicle body 14 shown in FIG. 5 indicates the vehicle body position at the time of braking, and it can be seen that only the vehicle body position has changed compared to the case of non-braking shown in FIG. Therefore, it is possible to obtain a braking ratio according to the target distribution indicated by the thick line in FIG. 8, and it is possible to obtain stable braking since the rear wheel braking force does not decrease.

The present invention is not limited to the above embodiment, but can employ various configurations. In the embodiment, the rear axle 12 is rotatably held inside the axle case 11 to which the lever 18 is welded and fixed. However, like the rear axle of the FF vehicle, the lever 18 is attached to the non-rotating rear axle by bolts or the like. It may be fixed. The lever 18 only needs to be attached to a position that moves up and down together with the rear wheel, and can be attached to the suspension arm 13. As described above, if the lever 18 is attached to the suspension arm 13, the present invention can be applied to an automobile employing an independent suspension for the rear wheels.

In the above-described embodiment, the response element 21
The slide pin 51 which is operated by hydraulic pressure from the master cylinder is used as means for holding the sliding shaft 17 on the sliding shaft 17. May be a simple structure. Further, it is also possible to mount the brake control device main body 19 and the sliding shaft 17 on the axle case 11 side and mount the lever 18 on the vehicle body 14 side. In this case, the responder 21 is
8, and a response body 21 is loosely fitted to the slide shaft 17 with a spring 22 disposed above the distal end annular portion 20 a of the detection lever 20 of the brake control device main body 19. You.

[0023]

As described above, according to the vehicle brake control device of the present invention, the following effects can be obtained. A brake control device main body that reduces the hydraulic pressure from the master cylinder in accordance with the suspension stroke of the rear axle and transmits the reduced pressure to the rear wheel brake is provided. A responding body opposed via a repelling means is slidably mounted on a sliding shaft arranged in the stroke direction of the vehicle body, and means for fixing the responding body to the sliding shaft during braking is provided. Since the control device main body and the sliding shaft are mounted on either the vehicle body side or the rear axle side, and the locking member for locking the responsive element is mounted on the other side of the vehicle body side or the rear axle side. Even if the center of gravity of the vehicle moves forward at the start of braking, the dimensions of the suspension displacement detector and the rear axle do not change. Therefore, since the braking control device body does not excessively reduce the braking force of the rear wheel due to a change in posture during braking, a sufficient braking force is exerted also on the rear wheel, and stable braking can be obtained. Since the braking force does not decrease at the time of braking, it is easy to match design prediction with actual performance, which is advantageous in design. The above effect can be obtained only by changing peripheral parts without changing the conventional control valve, which is advantageous in terms of design and cost. Means for holding the responsive body on the sliding shaft during braking is provided on the rugged engaging portion provided on the sliding shaft, and is provided on the responsive body to engage the uneven engaging portion at the start of braking. Since it is constituted by the matching slide pins, it can follow the displacement of the vehicle body during braking, so that stable characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 shows the entire configuration of an automobile equipped with a braking control device according to the present invention, and FIG.
FIG. 1B is a partial cross-sectional view showing a state in which constant load non-braking is performed.

FIG. 2 is a partial sectional view showing a lightly loaded state of the vehicle brake control device according to the embodiment of the present invention.

FIG. 3 is a partial sectional view showing a constant loading state of the vehicle braking control device according to the embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing a state of the vehicle brake control device according to the embodiment of the present invention when braking is started.

FIG. 5 is a partial cross-sectional view showing a state during braking of the vehicle braking control device according to the embodiment of the present invention.

FIG. 6 is a cross-sectional view showing an internal structure of a brake control device main body.

FIG. 7 is a cross-sectional view showing a response body.

FIG. 8 is a graph showing braking forces of front and rear wheels.

FIG. 9 is a partial view showing a conventional braking control device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 axle case 12 rear axle 14 vehicle body 17 sliding shaft 18 lever (locking member) 19 main body of brake control device 20 detection lever (suspension displacement amount detection unit) 21 responder 22 spring (repelling means) 23 engagement unit 25 control Valve 30 Piston 51 Slide pin

Claims (2)

[Claims] 1. A brake control device main body that reduces a hydraulic pressure from a master cylinder according to a suspension stroke of a rear axle and transmits the reduced pressure to a rear wheel brake, a suspension displacement amount detection unit of the brake control device main body, and the suspension displacement A means for slidably mounting a responsive body opposed to the amount detecting unit via a resilient means on a sliding shaft arranged in the stroke direction of the vehicle body, and fixing the responsive body to the sliding shaft during braking. The braking control device main body and the sliding shaft are mounted on either the vehicle body side or the rear axle side, and the locking member for locking the responsive element is provided on either the vehicle body side or the rear axle side. A vehicle braking control device, which is mounted on the other side. 2. A means for holding the responsive element on the sliding shaft during braking is provided on an uneven engaging portion provided on the sliding shaft and the responsive element, and the means for holding the responsive element when braking is started. 2. The vehicle brake control device according to claim 1, wherein the brake control device comprises a slide pin engaged with the engagement portion.