JP3837183B2 - Disc brake device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric disk brake device used for braking a vehicle, and more particularly to a disk brake device having a configuration using a giant magnetostrictive element as an electric actuator for pressing a friction pad against a disk rotor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a brake device used in a vehicle using hydraulic pressure as a drive source has a problem that the number of components increases and the configuration becomes complicated due to hydraulic piping equipment and a hydraulic adjustment mechanism.
Recently, intelligent brake functions such as anti-lock brake systems and traction control systems have been actively used. In this case, it is necessary to add an electro-hydraulic control circuit that converts a predetermined electric signal into a mechanical operation of the hydraulic actuator in accordance with the locked state or slip state of the wheel. This complicates the control system.
[0003]
In view of this, in recent years, a rotary motor is used as the drive source, and a predetermined braking force is applied by pressing the friction material against the rotating body for braking via a rotation-linear conversion mechanism, a speed reduction mechanism, or the like. Has been proposed (see Japanese Patent Laid-Open No. 64-21229) and an electric brake device using piezoelectric ceramics as a drive source (see Japanese Patent Laid-Open No. 60-136629). .
[0004]
[Problems to be solved by the invention]
As described above, in an electric brake device that uses a rotary motor or piezoelectric ceramics as a drive source, it is easy to make intelligent brake functions such as an anti-lock brake system and a traction control system.
[0005]
However, in a brake device that uses a rotary motor as a drive source, there is a problem that the brake device becomes large due to the provision of a rotation-linear conversion mechanism, a speed reduction mechanism, and the like.
On the other hand, in a brake device using piezoelectric ceramics as a drive source, the linear motion necessary for the forward / backward movement of the friction material can be obtained directly from the drive source, and it is not necessary to use a rotation-linear conversion mechanism, a speed reduction mechanism, or the like. Although it is possible to reduce the size of the brake device, the piezoelectric ceramic has a problem that a device for generating a large voltage is required.
[0006]
The present invention has been made in view of the above situation, and it is easy to make intelligent brake functions such as an anti-lock brake system and a traction control system, and it is suitable for downsizing of the apparatus and is responsive. It aims at providing the disc brake device excellent in the point.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a disk brake device according to the present invention includes a disk rotor that is a rotating body for braking, and a friction that exerts a braking force by being opposed to the surface of the disk rotor and pressed against the disk rotor. A pad, a brake caliper that holds the friction pad in a predetermined position with respect to the disk rotor, an electric actuator that generates a pressing force necessary to press the friction pad against the disk rotor, and a brake operation unit And a control unit for controlling the operation of the actuator according to the operation state of the disk brake device, and obtaining a desired braking force by adjusting the pressing force generated by the actuator, wherein the disk rotor comprises: The pair of disk-shaped rotor members are connected so as to be relatively movable only in the direction of the rotation axis. In addition, the actuator is provided to be sandwiched between a pair of rotor members of the disk rotor, and when the magnetic field is applied, the actuator expands to widen the space between the rotor members, thereby A super magnetostrictive element that is pressed against the disk rotor, and an electromagnetic coil that is mounted on the brake caliper and applies a magnetic field corresponding to an input current to the super magnetostrictive element via the brake caliper, and the control unit includes: The brake coil according to the operation state of the brake operation unit is generated by controlling the input current of the electromagnetic coil.
[0008]
Further, in the above-described disc brake device, the brake caliper is fixedly installed at a fixed position around the disc rotor, and the disc rotor is interposed between a pair of friction pads provided on the brake caliper. The rotor is supported so as to be movable in the rotation axis direction of the rotor.
[0009]
Furthermore, in the above-described disc brake device, the brake caliper is provided so as to be movable only in the rotation axis direction of the disc rotor at a fixed position around the disc rotor, and one rotor constituting the disc rotor. The member is characterized in that the position in the rotation axis direction is fixed.
[0010]
In the above configuration, when the brake operation is performed, the control unit inputs a current having a magnitude corresponding to the operation state of the brake operation unit at that time to the electromagnetic coil. The electromagnetic coil forms a magnetic field according to the input current. The magnetic field formed by the electromagnetic coil is applied to the giant magnetostrictive element provided between the pair of rotor members of the disk rotor via the brake caliper. By applying this magnetic field, the giant magnetostrictive element expands, widening the gap between the pair of rotor members, and relatively narrowing the gap between the disk rotor and the friction pad. Accordingly, when the amount of expansion of the giant magnetostrictive element exceeds a certain value, the gap between the disk rotor and the friction pad disappears, and the friction pad is pressed against the disk rotor, and the braking force is activated.
On the other hand, when the brake operation is released, the control unit stops applying current to the electromagnetic coil, so the magnetic field that stretched the giant magnetostrictive element is eliminated, and the giant magnetostrictive element is reduced to its original state. Since the distance between the pair of rotor members is narrowed, the braking state is released.
[0011]
That is, the disk brake device of the present invention has a built-in super magnetostrictive element that extends when a magnetic field is applied, and presses the friction pad against the disk rotor by increasing the thickness of the disk rotor by extending the super magnetostrictive element. In this way, the linear relative displacement operation between the friction pad and the disk rotor necessary for pressing the friction pad against the disk rotor can be obtained directly from the giant magnetostrictive element as the drive source.
[0012]
Further, the extension operation of the giant magnetostrictive element can be directly and electrically controlled by the current applied to the electromagnetic coil provided in the brake caliper. Furthermore, the extension amount in the giant magnetostrictive element can be easily increased by increasing the magnetic field applied to the giant magnetostrictive element, that is, by increasing the applied current of the electromagnetic coil.
[0013]
Moreover, since the giant magnetostrictive element as the driving source is built in the disk rotor, the brake caliper need not be processed to equip the driving source, and the input signal line is also connected to the disk rotor side. Is not required.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a disc brake device according to the present invention will be described in detail with reference to the drawings.
1 to 6 show an embodiment of a disc brake device according to the present invention. FIG. 1 is a cross-sectional view of a main part of the disc brake device of the embodiment, and FIG. 3 is a sectional view taken along line BB in FIG. 2, FIG. 4 is a sectional view taken along line CC in FIG. 1, FIG. 5 is a sectional view taken along line DD in FIG. 2, and FIG. It is the schematic which shows arrangement | positioning of the brake caliper in the disc brake apparatus of a form.
[0015]
The disc brake device 1 is provided as a disc brake for a vehicle, and exhibits a braking force by being placed against the surface of the disc rotor 2 and being pressed against the disc rotor 2 as a rotating body for braking. And the brake caliper 10 which is a structure for holding the friction pad 3 in a predetermined position with respect to the disk rotor 2 and the pressing force required to press the friction pad 3 against the disk rotor 2 And an electric actuator 4 that generates the control and a control unit (ECU) 8 that controls the operation of the actuator 4 in accordance with the operation state of the brake pedal 6 that is a brake operation unit.
[0016]
The disk rotor 2 has a configuration in which a pair of disk-like rotor members 2a and 2b are coupled so as to be relatively movable only in the rotation axis direction (left and right direction in FIG. 1).
Each of the pair of rotor members 2a and 2b is formed of a paramagnetic material such as stainless steel or aluminum. As shown in FIG. By fitting the irregularities 5a and 5b, they are connected so as to be relatively movable only in the direction of the rotation axis.
Asperities 5a and 5b are appropriately provided at predetermined intervals in the circumferential direction so that the rotor members 2a and 2b can smoothly move relative to each other in the rotation axis direction.
[0017]
A pair of friction pads 3 are provided so as to sandwich the disk rotor 2. Each friction pad 3 is fixedly mounted on both inner sides of a brake caliper 10 having a substantially U-shaped cross section.
[0018]
The actuator 4 includes a rod-shaped giant magnetostrictive element 12 that increases in length due to magnetostriction when a magnetic field is applied, and an electromagnetic coil 14 that applies a magnetic field corresponding to an input current to the giant magnetostrictive element 12.
Here, the giant magnetostrictive element 12 is incorporated between the pair of rotor members 2a and 2b so that the axial direction is directed to the rotational axis direction of the disk rotor 2 and is sandwiched between the pair of rotor members 2a and 2b. When the magnetic field is applied, the friction pad 3 is pressed against the disk rotor 2 by expanding and widening the distance between the pair of rotor members 2a and 2b.
As shown in FIG. 4, the giant magnetostrictive element 12 has a disk rotor so that the expansion of the space between the rotor members 2a and 2b due to the extension of the giant magnetostrictive element 12 is the same at any position in the circumferential direction of the disk rotor 2. 2 are distributed evenly in the circumferential direction.
[0019]
In this embodiment, as shown in FIG. 2 and FIG. 3, the side wall 10a of the brake caliper 10 is compared with the central part where the friction pad 3 is provided at both ends in the circumferential direction of the brake caliper 10. The gap between the side wall portions 10a is narrowed so as to minimize the gap S between the disk rotor 2 and the leakage of magnetic flux applied to the giant magnetostrictive element 12 via the brake caliper 10 is prevented.
[0020]
The electromagnetic coil 14 is fixedly mounted on the brake caliper 10, forms a magnetic circuit 9 shown by a dotted line in FIG. 1 on the brake caliper 10, and the magnetostrictive element in the disk rotor 2 through the brake caliper 10. A magnetic field is applied to 12.
[0021]
In the case of this embodiment, the brake caliper 10 is fixedly installed at a fixed position around the disk rotor 2. The disk rotor 2 is supported so that one rotor member (outer rotor) 2a can move in the direction of the rotation axis of the disk rotor 2 between a pair of friction pads 3 mounted on the brake caliper 10. ing.
In the case of this embodiment, as shown in FIG. 6, three brake calipers 10 are provided at three equal intervals in the circumferential direction of the disc rotor 2. This is because the expansion of the space between the rotor members 2 a and 2 b due to the expansion of the giant magnetostrictive element 12 is made as uniform as possible over the entire circumference of the disk rotor 2.
[0022]
When the brake pedal 6 is stepped on by the driver, the stroke or pedaling force signal that is stepped on at that time is input to the control unit 8 by a known sensor 16.
[0023]
The control unit 8 detects the driver's braking command based on a signal from the sensor 16 and controls the operation of the actuator 4. The control unit 8 inputs the electromagnetic coil 14 according to the signal from the sensor 16 during a brake operation. Control the current.
[0024]
In the disc brake device 1 described above, the super magnetostrictive element 12 that expands when a magnetic field is applied is built in the disc rotor 2, and the thickness of the disc rotor 2 is increased by the extension of the super magnetostrictive element 12. A linear relative displacement operation between the friction pad 3 and the disk rotor 2 that is required to press the friction pad 3 against the disk rotor 2 is applied to the disk rotor 2 by a giant magnetostriction as a drive source. It can be obtained directly from the element 12.
Therefore, it is not necessary to use a rotation-linear conversion mechanism, a speed reduction mechanism, or the like, so that the brake device can be reduced in size.
[0025]
In addition, since the extension operation of the giant magnetostrictive element 12 can be directly electrically controlled by the current applied to the electromagnetic coil 14 provided in the brake caliper 10, the brake function such as the anti-lock brake system or the traction control system is provided. It is easy to make intelligent.
[0026]
Further, the amount of expansion in the giant magnetostrictive element 12 can be easily increased by increasing the magnetic field applied to the giant magnetostrictive element 12, that is, by increasing the current applied to the electromagnetic coil 14, compared to the case of piezoelectric ceramics. The amount of displacement for pressing the friction pad 3 against the disk rotor 2 can be increased, and the wear allowable capacity of the friction pad 3 can be increased.
Further, the response of the actuator 4 can be improved as compared with the case of the piezoelectric ceramic.
[0027]
Moreover, since the giant magnetostrictive element 12 as the driving source is built in the disc rotor 2, the brake caliper 10 does not require any processing for mounting the driving source, and the structure of the brake caliper 10 is simplified correspondingly. Thus, the rigidity can be improved. Further, since the giant magnetostrictive element 12 incorporated in the disk rotor 2 as a driving source is operated by a magnetic field by the electromagnetic coil 14 provided on the brake caliper 10, it is necessary to connect an input signal line or the like to the disk rotor 2. Absent.
[0028]
In the above-described embodiment, the brake caliper 10 is fixed in the direction of the rotation axis of the disk rotor 2 and the disk rotor 2 is movable in the direction of the rotation axis. Instead, the brake caliper 10 is connected to the disk rotor 2. It is also possible to equip the disk rotor 2 so that it can move only in the rotational axis direction of the disk rotor 2 at a fixed position around the disk rotor 2 and to fix one rotor member 2a constituting the disk rotor 2 in the rotational axis direction.
[0029]
FIG. 7 is a cross-sectional view of a main part of another embodiment of the disc brake device according to the present invention.
In the case of this other embodiment, each of the rotor members 2a, 2b constituting the disk rotor 2 is formed by casting of a paramagnetic material such as stainless steel or aluminum, as in the case of one embodiment. A pressure receiving wall 15 made of a ferromagnetic material is provided at a portion where the giant magnetostrictive element 12 is sandwiched. The pressure receiving wall 15 is cast in a predetermined position when the rotor members 2a and 2b are cast, and is integrated with the rotor members 2a and 2b.
The configuration other than the provision of the pressure receiving wall 15 is the same as that of the above-described embodiment.
[0030]
As described above, when the pressure receiving wall 15 made of a ferromagnetic material is provided, the magnetic force lines 17 passing through the disk rotor 2 via the brake caliper 10 can be efficiently collected in the super magnetostrictive element 12. The magnetic field strength applied to 12 can be prevented from decreasing due to the leakage of magnetic flux.
[0031]
【The invention's effect】
As described above, according to the disc brake device of the present invention, a super magnetostrictive element that expands when a magnetic field is applied is built in the disc rotor, and the thickness of the disc rotor is increased by the extension of the super magnetostrictive element, thereby causing friction. The pad is pressed against the disk rotor, and the linear relative displacement movement between the friction pad and the disk rotor required to press the friction pad against the disk rotor is directly applied from the giant magnetostrictive element that is the driving source. Obtainable. Accordingly, it is not necessary to use a rotation-linear conversion mechanism, a speed reduction mechanism, or the like, so that the brake device can be reduced in size.
In addition, since the expansion operation of the giant magnetostrictive element can be directly controlled electrically by the current applied to the electromagnetic coil installed in the brake caliper, the brake functions such as the anti-lock brake system and traction control system can be made intelligent. Easy to plan.
Furthermore, the amount of expansion in the giant magnetostrictive element can be easily increased by increasing the magnetic field applied to the giant magnetostrictive element, that is, by increasing the current applied to the electromagnetic coil. The amount of displacement for pressing against the disk rotor 2 can be increased, and the wear tolerance capability of the friction pad can be increased.
Further, as compared with the case of piezoelectric ceramics, the response can be improved as an actuator.
Moreover, since the giant magnetostrictive element as the driving source is built in the disc rotor, the brake caliper does not require any processing to equip the driving source, and the structure of the brake caliper is simplified correspondingly and the rigidity is increased. Can be improved. Further, since the giant magnetostrictive element incorporated in the disk rotor as a driving source is operated by a magnetic field generated by an electromagnetic coil provided on the brake caliper, it is not necessary to connect an input signal line or the like to the disk rotor.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of a disc brake device according to an embodiment of the present invention.
FIG. 2 is a view taken in the direction of arrow A in FIG.
3 is a cross-sectional view taken along line BB in FIG.
4 is a cross-sectional view taken along the line CC in FIG. 1. FIG.
5 is a cross-sectional view taken along line DD in FIG.
FIG. 6 is a schematic view showing an arrangement of brake calipers in the disc brake device according to the embodiment of the present invention.
FIG. 7 is a cross-sectional view of a main part of another embodiment of the disc brake device according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Disc brake device 2 Disc rotor 2a, 2b Rotor member 3 Friction pad 4 Actuator 5a, 5b Concavity and convexity 6 Brake pedal 8 Control unit (ECU)
10 Kirake caliper 12 Giant magnetostrictive element 14 Electromagnetic coil 16 Sensor

Claims (3)

A disc rotor which is a rotating body for braking; a friction pad which is arranged opposite to the surface of the disc rotor and exerts a braking force by being pressed against the disc rotor; and the friction pad at a predetermined position with respect to the disc rotor A brake caliper that holds the motor, an electric actuator that generates a pressing force necessary to press the friction pad against the disc rotor, and a control unit that controls the operation of the actuator in accordance with the operating state of the brake operation unit And
A disc brake device that obtains a desired braking force by adjusting the pressing force generated by the actuator,
The disk rotor has a configuration in which a pair of disk-shaped rotor members are connected so as to be relatively movable only in the rotation axis direction,
The actuator is equipped so as to be sandwiched between a pair of rotor members of the disk rotor, and expands when a magnetic field is applied to widen the space between the rotor members and press the friction pad against the disk rotor. A giant magnetostrictive element, and an electromagnetic coil that is mounted on the brake caliper and applies a magnetic field corresponding to an input current to the giant magnetostrictive element via the brake caliper;
The disc brake device, wherein the control unit controls an input current of the electromagnetic coil to generate a braking force according to an operation state of the brake operation unit. The brake caliper is fixedly installed at a fixed position around the disc rotor, and the disc rotor is movable between a pair of friction pads provided on the brake caliper in the direction of the rotation axis of the disc rotor. The disc brake device according to claim 1, wherein the disc brake device is supported. The brake caliper is mounted at a fixed position around the disk rotor so as to be movable only in the rotation axis direction of the disk rotor, and one rotor member constituting the disk rotor has a position in the rotation axis direction. The disc brake device according to claim 1, wherein the disc brake device is fixed.

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