JP3289452B2 - Braking force control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force control device.

[0002]

2. Description of the Related Art A conventional technique of this kind is disclosed in
A technique disclosed in Japanese Patent Application Laid-Open No. -5270 is known. This is to detect the initial operation position of the plunger of the variable displacement actuator by a position sensor and drive the plunger to the initial operation position by driving a motor.

[0003]

However, in the above-described conventional technique, when the plunger is driven near the position where the volume of the pressure control chamber is kept at a maximum, the plunger stops due to a motor failure or the like. This leads to the deterioration of braking effectiveness and brake feeling. As means for preventing this, a bypass passage provided in parallel with the variable volume actuator in the hydraulic path and a valve device for switching between communication and shutoff of the bypass passage are used to connect the bypass passage when the motor is damaged. In some cases, the brake operation is normally performed, but the number of components increases and the cost increases.

[0004] It is a technical object of the present invention to provide a braking force control device capable of performing a normal brake operation without increasing costs even when a motor is damaged.

[0005]

In order to solve the above-mentioned technical problem, the technical means adopted in the invention of claim 1 is a master cylinder which generates a brake hydraulic pressure by operating a brake operating member, A wheel cylinder that receives the brake fluid pressure to apply braking force to the wheels, a pressure control chamber that communicates with the wheel cylinder, and a pressure control chamber that communicates with the master cylinder. Blocking means capable of blocking the hydraulic pressure path, a variable volume actuator that changes the volume of the pressure control chamber, and a control device that controls the variable volume actuator to control the brake hydraulic pressure applied to the wheel cylinder. a braking force control apparatus provided with the variable volume <br/> actuator plug for changing the volume of said pressure control chamber by movement A plunger, a plunger driving unit that engages with the plunger to drive the plunger, a first urging unit that urges the plunger in a direction in which a volume of the pressure control chamber increases, and a volume of the pressure control chamber. Second urging means for urging the plunger in a direction in which the plunger decreases, and disengagement means for disengaging the plunger from the plunger driving means when returning the plunger to the initial operating position. In the braking force control device , the disengagement hand
A step provided with a first engagement portion provided on the plunger;
Always engages with the plunger drive means and engages with the first engagement portion.
An engagement member having an engageable second engagement portion;
The engaging member is moved in a direction in which the joint portion engages with the first engaging portion.
And third biasing means for biasing .

[0006]

A technical measure taken in the second aspect of the present invention is that the first and second engaging portions have a tapered shape.

According to a third aspect of the present invention, there is provided a bearing provided between the engaging member and the third biasing means.

[0009]

The operation of the first aspect will be described. The plunger is urged by the first urging means in a direction in which the volume of the pressure control chamber increases, and by the second urging means in a direction of decreasing the volume of the pressure control chamber. When the engagement is released, it is possible to stop at a position where the urging forces of both urging means are balanced, that is, at an initial operating position. The initial operating position can be determined by arbitrarily setting the urging forces of both urging means. Further, if the engagement between the plunger and the plunger driving means is released by the engagement releasing means, the plunger is moved to the initial operating position by the urging forces of both the urging means, so that the plunger keeps the volume of the pressure control chamber to the maximum. When the motor is driven near the position, even if the motor fails, the plunger does not stop at that position, so that the normal brake operation can be performed.

Further, the engagement releasing means has a first engaging portion provided on the plunger and a second engaging portion which is always engaged with the plunger driving means and is engageable with the first engaging portion. By providing an engaging member and third urging means for urging the engaging member in a direction in which the second engaging portion engages with the first engaging portion,
When the pressing force from the pressure control chamber is not applied to the plunger, and when the plunger driving means is stopped,
The engagement between the plunger and the plunger driving means is released. With such a simple configuration, the engagement between the plunger and the plunger driving means can be released, and the cost is low.

The operation of the invention of claim 2 will be described. Since the first and second engagement portions have a tapered shape, the first and second engagement portions have a first shape.
The second engaging portion has a simple shape and is low in cost.

The operation of the third aspect will be described. The provision of the bearing disposed between the engagement member and the third urging means allows the plunger to follow smoothly without disturbing the movement of the plunger at the time of disengagement.

[0013]

An embodiment according to the present invention will be described with reference to the drawings.

FIG. 1 is a diagram of a brake hydraulic circuit provided with a braking force control device according to the present invention.

In this embodiment, anti-lock control for preventing wheel lock and shortening the braking distance, anti-slip control for preventing wheel slip and effectively accelerating the vehicle, and the danger in front of the vehicle are provided. A description will be given of a braking force control device for performing an automatic brake control for automatically decelerating the vehicle upon sensing, but is not particularly limited thereto.

In FIG. 1, the operating force of a brake pedal 10 is boosted by a brake booster 11 to operate a master cylinder 12, and brake fluid is directed toward wheel cylinders 20, 21, 22, and 23 via a hydraulic pressure path 14. Pressure is applied. Reference numeral 13 denotes a brake reservoir for supplying brake fluid to the master cylinder 12, and 10a denotes a well-known pedal switch.

Each of the wheels FR, FL is controlled by the brake fluid pressure.
, RR, RL braking wheel cylinders 20, 2
1, 22 and 23 communicate with the master cylinder 12 via a hydraulic path 14, and on this hydraulic path 14, a volume variable actuator for changing the volume of a pressure control chamber 48 (FIG. 2) by a motor 31. 30 are provided.
The one-way valve 16 that allows only the flow from the wheel cylinders 20 and 21 to the master cylinder 12 is provided in the hydraulic pressure path 14 on the front wheel side in parallel with the variable volume actuator 30.

Each of the motors 31 has an electronic control unit CP
The drive is controlled by U. This electronic control unit CP
U recognizes the necessity of the braking force control of each wheel from each sensor, controls the driving of the motor 31, and controls the braking force applied to the wheel.

On the other hand, a well-known proportioning valve 15 is disposed between the master cylinder 12 and the variable displacement actuator 30 on the hydraulic path 14 on the rear wheel side.

Next, the variable volume actuator 30 will be described with reference to FIG. FIG. 2 is a sectional view of the variable volume actuator 30.

Referring to FIG.
0, the first, second, and third members 32, 33,
34, each of which is connected by a bolt (not shown). A cylindrical through hole 33a is formed in the second member 33 of the housing, and the first and second plungers 35 and 36 are internally provided with the piston cup 3 therein.
It is disposed so as to be slidable in a liquid-tight manner via the members 7 and 38.

The first plunger 35 is provided with large-diameter and small-diameter cylinders 35a and 35b opened downward and a tapered portion 35c serving as a first engagement portion, and a rotary shaft 39 is inserted into these cylinders. ing. The rotation shaft 39 is connected to the second member 33.
Is mounted in the through hole 33a of the motor 31 through a bearing 47, and the speed reduction mechanism 4 is attached to the output shaft 31a of the motor 31.
It engages via the pins 0 and 41 and is further threaded on the outer periphery so as to mesh with the engaging member 42. The engaging member 42 is moved up and down by the rotation of the rotating shaft 39, and is in contact with a spring 44 serving as third urging means via a thrust bearing 43, and is constantly urged upward in the drawing. As a result, the tapered portion 4 serving as the second engagement portion
2a is in contact with the tapered portion 35c of the first plunger 35.

Further, the lower end of the first plunger 35 is
The second plunger 36 is urged upward by contacting a second return spring 45 serving as urging means, and is in contact with a shoulder 36 a provided on the second plunger 36 (initial operation position). Also, rotating shaft 3
9 above the bearing 47 holding the metal ring 4.
8 is provided to regulate the amount of movement of the first plunger 35.

The second plunger 36 is urged downward by a first return spring 46 serving as a first urging means having a greater spring force than the second return spring 45, and is provided on the second member 33 of the housing. Locking part 33
b (initial operating position).

The first and second plungers 35, 36 are constantly urged toward the initial operation position by the first and second return springs 46, 45.

The first and second plungers 35, 36
Are the upper surface and the first and second members 32, 3 of the housing.
3 together with a pressure control chamber 48, which communicates with the hydraulic path 14 via each port 49, 50 and has first and second valves 51, 52. .

The first valve 51 includes a valve seat member 53 press-fitted into the hole 32a of the first member 32 of the housing, and a piston cup 55 fitted to a rod 54 having one end inserted into a cylindrical hole 35d of the first plunger 35. And a valve member 56 loosely slidably inserted through the valve member 56. Valve member 56
Is urged upward by a spring 57 and the rod 54
Is locked to the large-diameter portion 54a.

The second valve 52 comprises a ball valve body 58 and a small diameter portion 32b of the first member 32 serving as a valve seat. The ball valve element 58 is urged by the spring 59 toward the small-diameter portion 32b, and the lower end thereof is
4 is supported.

Next, the operation of this embodiment will be described.

When the vehicle is running, the plunger 33 is in the initial operating position by the first and second return springs 46 and 45. When the electronic control unit CPU determines that the vehicle needs to be decelerated via a sensor that detects the following distance, the vehicle speed, the driver's falling asleep, an obstacle ahead, and the like, the motor 31 is driven (corrected). When the first plunger 35 is moved upward (in FIG. 2) by moving the second plunger 36 upward, the second plunger 36 is also moved upward. As a result, the rod 54 moves upward, the valve body member 56 contacts the valve seat member 53, the first valve 51 is closed, the hydraulic pressure path 14 is shut off, and the pressure control chamber 48 and the wheel cylinders 20, 21, 22 are closed. , 23 are sealed. When the motor 31 is further driven (forward rotation) to move the first and second plungers 35 and 36 upward, the pressure control chamber 36
, The pressure increases and the braking force is applied to the wheels.

At this time, the driver operates the brake pedal 10
When the brake fluid pressure generated from the master cylinder 12 overcomes the urging force of the spring 57 and the brake fluid pressure in the pressure control chamber 48, the first valve 51 opens to provide a braking force required by the driver. It is generated to match the driver's brake feeling.

On the other hand, when the driver depresses the brake pedal 10 to obtain a braking force (during normal braking), a brake fluid pressure is generated from the master cylinder 12 and applied to the wheel brakes 10, 21, 22, and 23. A braking force is generated.

For example, while traveling on a low μ road (snow road, frozen road, etc.), when an excessive braking force is applied to the wheels and the electronic control unit CPU detects that the wheels are locked, the electronic control unit CPU adjusts the corresponding variable volume. The motor 31 of the actuator 30 is driven to rotate the first plunger 35 in the reverse direction so as to move downward (in FIG. 2). As a result, the rod 54 moves downward, and the ball valve pair 58 abuts on the small- diameter portion 32b of the first member 32 by the action of the spring 59, so that the hydraulic path 14 is cut off and the pressure control chamber 48 is closed. And the corresponding wheel cylinder are hermetically sealed.
When the first plunger 35 is further moved downward, the volume in the pressure control chamber 48 is increased , and the brake fluid pressure is reduced. As a result, the braking force exerted on the locked wheel is reduced, and the wheel is controlled so as to grip the road again.

On the other hand, when the driver recognizes that the need for deceleration of the vehicle is no longer necessary and releases the brake pedal 10, the brake fluid returns to the master cylinder 12 and the master valve 12 side of the second valve 52 and the wheel The pressure difference with the cylinder side increases. When this pressure difference overcomes the biasing force of the spring 59, the second valve 52 opens and the braking force is reduced.

Also, when the vehicle starts moving, an excessive driving force is applied to the wheels to slip on the road surface.
Is detected, the motor 31 of the variable displacement actuator 30 corresponding to the drive wheel is driven to rotate the first plunger 35 forward (in FIG. 2). As a result, the first and second plungers 35 and 36 move upward, and the first and second plungers 35 and 36 move upward.
The valve 51 shuts off the hydraulic path 14 to seal the pressure control chamber 48 and the corresponding wheel cylinder. Then, the first and second plungers 35 and 36 further move upward (in FIG. 2).
By doing so, a braking force is applied to the driving wheels by the same operation as described above, and the driving wheels can be gripped on the road surface and the vehicle can be effectively accelerated.

Further, the first and second plungers 35, 36
Is returned to the initial operating position, the motor 31 is driven (reversely rotated) to move the first plunger 35 downward (in FIG. 2), and then, for example, is driven to a position where it contacts the metal ring 48, and then the motor 31 is stopped. Then, the first plunger 35 moves upward by the action of the second return spring 45. Since the second return spring 45 is superior to the spring force of the spring 44, the engagement member 42 and the first
The taper portions 42a and 35c of the plunger 35 are separated, and the engagement between the engaging member 42 and the first plunger 35 is released.
Thereby, the engaging member 42 also moves upward with the upward movement of the first plunger 35. At this time, the engagement member 42 moves upward while rotating on the bearing 43.

The engagement between the engaging member 42 and the first plunger 35 is such that the reaction force from the pressure control chamber 48 is not applied to the first plunger 35 and the rotating shaft 39 moves up the engaging member 42 ( It is released when it does not rotate to rotate (see FIG. 2).

In this embodiment, the first and second plungers 3
5 and 36 are first and second return springs 46 and 4
5 is always urged toward the initial operating position, and when the engagement between the engaging member 42 and the first plunger 35 is released, the action of the two return springs 46 and 45 causes
It returns to the initial operating position.

When the engagement between the engagement member 42 and the first plunger 35 is released, both return springs 46 and 45 are released.
Is moved to the initial operating position by the spring force of
When the plunger 35 is driven near the position where the volume of the pressure control chamber 48 is kept at its maximum, even if the motor 31 fails, the first plunger 35 does not stop at that position. Can be performed.

Further, the engagement between the engagement member 42 and the first plunger 35 may be electrically released by using an electromagnetic clutch or the like as the engagement release means, but this increases the cost. However, in this embodiment, the disengagement means is the first
A tapered portion 35c provided on the plunger 35 and a tapered portion 3
Engaging member 42 having tapered portion 42a engageable with 5c
And the tapered portion 42a of the engagement member 42
And a spring 44 for urging the engaging member 42 in a direction to engage with the tapered portion 35c of the fifth plunger 35 when the reaction force from the pressure control chamber 48 is not applied to the first plunger 35 and the rotation shaft When 39 is stopped, the first
The engagement between the plunger 35 and the engagement member 42 is released.
With such a simple configuration, the engagement between the plunger and the plunger driving means can be released, and the cost is low.

Further, since the first and second engaging portions 35c and 42a have tapered shapes, the first and second engaging portions have a simple shape, and the cost is low.

The provision of the bearing 43 disposed between the engaging member 42 and the spring 44 allows the first plunger 35 to smoothly follow the disengagement without hindering the movement.

[0043]

The effect of the first aspect of the present invention will be described. The plunger is urged by the first urging means in a direction in which the volume of the pressure control chamber increases, and by the second urging means in a direction of decreasing the volume of the pressure control chamber. When the engagement is released, it is possible to stop at a position where the urging forces of both urging means are balanced, that is, at an initial operating position. The initial operating position can be determined by arbitrarily setting the urging forces of both urging means. Further, if the engagement between the plunger and the plunger driving means is released by the engagement releasing means, the plunger is moved to the initial operating position by the urging forces of both the urging means, so that the plunger keeps the volume of the pressure control chamber to the maximum. When the motor is driven near the position, even if the motor fails, the plunger does not stop at that position, so that the normal brake operation can be performed.

Further , the engagement releasing means has a first engaging portion provided on the plunger and a second engaging portion which is always engaged with the plunger driving means and is engageable with the first engaging portion. By providing an engaging member and third urging means for urging the engaging member in a direction in which the second engaging portion engages with the first engaging portion,
When the pressing force from the pressure control chamber is not applied to the plunger, and when the plunger driving means is stopped,
The engagement between the plunger and the plunger driving means is released. With such a simple configuration, the engagement between the plunger and the plunger driving means can be released, and the cost is low.

The effect of the invention of claim 2 will be described. Since the first and second engagement portions have a tapered shape, the first and second engagement portions have a first shape.
The second engaging portion has a simple shape and is low in cost.

The effect of the third aspect of the present invention will be described. The provision of the bearing disposed between the engagement member and the third urging means allows the plunger to follow smoothly without disturbing the movement of the plunger at the time of disengagement.

[Brief description of the drawings]

FIG. 1 is a diagram of a brake hydraulic circuit including a braking force control device according to the present invention.

FIG. 2 shows a sectional view of a volume increasing / decreasing actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Brake pedal 12 ... Master cylinder 14 ... Hydraulic circuit 20, 21, 22, 23 ... Wheel cylinder 30 ... Variable volume actuator 31 ... Motor 32 ... 1st member (Housing) 33 ... second member (housing) 34 ... third member (housing) 35 ... first plunger 35c ... taper portion (first engagement portion) 36 ... second plunger 39: rotating shaft 42: engaging member 42a: tapered portion (second engaging portion) 43: bearing 44: spring (third biasing means) 45: second return Spring (second urging means) 46 ... first return spring (first urging means) 51 ... first valve 52 ... second valve

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-5270 (JP, A) JP-A-3-10955 (JP, A) JP-A-1-262244 (JP, A) JP-A-4- 169370 (JP, A) JP-A-3-167058 (JP, A) JP-A-3-96462 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60T 8/00-8 / 96 B60T 7/00-7/22

Claims (3)

(57) [Claims] 1. A master cylinder that generates brake fluid pressure by operating a brake operating member, and a wheel cylinder that communicates with the master cylinder via a fluid pressure path and receives the brake fluid pressure to apply braking force to wheels. A pressure control chamber that communicates with the wheel cylinder, a shutoff unit that can shut off the hydraulic path between the pressure control chamber and the master cylinder, a volume variable actuator that changes the volume of the pressure control chamber, a by controlling the container product varying actuator braking force control device and a control device for controlling the brake fluid pressure exerted on the wheel cylinders, the variable volume actuator, the volume of the pressure control chamber by movement A plunger to be changed, plunger driving means for driving the plunger by engaging with the plunger, First urging means for urging the plunger in a direction in which the volume increases, second urging means for urging the plunger in a direction in which the volume of the pressure control chamber decreases, and moving the plunger to an initial operating position. the braking force control apparatus provided with a disengagement means for disengaging the said plunger and said plunger drive means when returning, before
The engagement disengaging means includes a first engagement member provided on the plunger.
And the engaging portion is always engaged with the plunger driving means, and
An engagement member having a second engagement portion engageable with the first engagement portion
And in the direction in which the second engagement portion engages with the first engagement portion.
And third biasing means for biasing the engagement member.
Characteristic braking force control device . 2. The system according to claim 1, wherein said first and second members are connected to each other.
A braking force characterized in that the joint has a tapered shape.
Control device . 3. The method according to claim 1, wherein
A bearer disposed between the engaging member and the third urging means
A braking force control device comprising: