JP2004183694A - Disk brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disc break with a pressing force detection sensor in which space restriction for wiring is eliminated. <P>SOLUTION: A ball lamp mechanism 12 is driven by reducing rotation speed of a rotor 17 of an electric motor 9 by a differential speed reducing mechanism 10. A break pad 5 on one side is pressed onto a disk rotor 2 by moving a piston 11 forward. By using reaction force the break pad 6 on the other side is pressed onto the disk rotor 2 through the medium of a claw 4. By so doing, breaking force is generated. A sensor unit 38 is mounted on the claw 4 to act the reaction force from the disk rotor 2 on a straining plate 41 through the medium of a piston member 40. Bending deformation generated in the straining plate 41 is detected by a strain gage 42 to obtain pressing force of the disk rotor 2. Therefore, space on the side of the claw 4 is effectively utilized. Since a sensor unit 38 does not move against a caliper, wiring to the strain gage 42 can be easily carried out. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
[Industrial applications]
The present invention relates to a disc brake including a sensor for detecting a pressing force of a brake pad.
[0002]
[Prior art]
The rotational movement of the rotor of the electric motor is converted into linear movement of the piston using a rotation-linear movement conversion mechanism such as a ball screw mechanism or a ball ramp mechanism, and the brake pad is pressed against the disk rotor by the piston to reduce the braking force. 2. Description of the Related Art There is known an electric disc brake device that generates the electric power. The electric disc brake detects a driver's brake pedal depressing force (or displacement amount) by a sensor, and controls the rotation of the electric motor based on the detected value by a controller, thereby obtaining a desired braking force. .
[0003]
Some of the above-mentioned electric disc brakes include a sensor provided inside the piston for detecting the thrust of the piston (the pressing force of the brake pad), as described in Patent Document 1, for example. According to the electric disk brake incorporating such a sensor, the thrust of the piston can be directly fed back to the control system by a signal from the sensor, and the thrust of the piston can be directly fed back to the control system in response to a braking force request from the driver (brake pedal depression force). Appropriate piston thrust can be obtained.
[0004]
[Patent Document 1]
Japanese Unexamined Patent Publication No. Hei 11-513336
[Problems to be solved by the invention]
However, the conventional electric disk brake having a sensor provided inside the piston has the following problems. Generally, the piston of the electric disc brake has a stroke of up to about 20 mm in order to follow the wear of the brake pad. For this reason, the wiring connected to the sensor built in the piston needs to have a margin by a length that allows this stroke, but since the piston portion of the electric disc brake has almost no extra space, Wiring is very difficult, and the space for the wiring is an obstacle to reducing the caliper size.
[0006]
The present invention has been made in view of the above points, and an object of the present invention is to provide a disc brake including a pressing force detection sensor capable of eliminating a restriction on a wiring space.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 includes a piston facing one of brake pads arranged on both sides of a disk rotor, and a claw straddling the disk rotor and facing the other of the brake pads. In a caliper floating type disc brake in which a caliper provided with a part is movably supported by a carrier,
Detection means for detecting a pressing force of the brake pad against the disk rotor is provided on the claw portion.
With this configuration, it is possible to effectively use the space on the claw portion side, and since the detection means does not move with respect to the caliper, wiring to the detection means is facilitated.
According to a second aspect of the present invention, in the configuration of the first aspect, the detecting means includes a strain generating member that deforms by receiving a reaction force of a pressing force of the brake pad against the disk rotor; And a distortion detecting means for detecting distortion of the distortion member.
With this configuration, it is possible to obtain the pressing force of the brake pad against the disk rotor based on the strain of the strain generating member detected by the strain detecting unit. In the disk brake according to the third aspect of the present invention, in the configuration of the second aspect, the strain generating member is provided between the brake pad and the claw portion, and is bent and deformed by a reaction force from the brake pad. Wherein the strain detecting means is a strain gauge mounted on the strain generating plate.
With this configuration, it is possible to obtain the pressing force of the brake pad against the disk rotor based on the bending deformation of the strain plate detected by the strain gauge.
Also, in the disk brake according to the fourth aspect of the present invention, in the configuration of the third aspect, the strain plate receives a reaction force from the brake pad at two points, and the strain plate receives the reaction force from the brake pad. The strain gauge is mounted between two points receiving a reaction force.
With this configuration, the bending moment generated in the strain plate by the reaction force from the brake pad becomes uniform between two points receiving the reaction force from the brake pad.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
A first embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the electric disc brake 1 has a caliper body 3 disposed on one side (usually inside the vehicle body) of a disc rotor 2 that rotates with wheels (not shown). A claw portion 4 formed in a substantially C shape and extending to the opposite side across the disk rotor 2 is integrally connected to the caliper body 3 by a bolt (not shown). Brake pads 5 and 6 are provided on both sides of the disk rotor 2, that is, between the disk rotor 2 and the caliper body 3 and between the disk rotor 2 and the tip of the claw portion 4, respectively. The brake pads 5 and 6 are supported by a carrier 7 fixed to the vehicle body so as to be movable in the axial direction of the disk rotor 2, so that the braking torque is received by the carrier 7. Are mounted on the caliper body 3 and are slidably guided along the axial direction of the disk rotor 2 by slide pins 8 slidably provided on the carrier 7.
[0009]
The caliper body 3 includes an electric motor 9, a differential reduction mechanism 10 for reducing the rotation of the electric motor 9, and a rotational motion of the electric motor 9 reduced by the differential A ball ramp mechanism 12 for moving the piston 11 in contact with the pad 5 is provided, and a pad wear compensation mechanism 13 for adjusting the position of the piston 11 according to wear of the brake pads 5 and 6 is provided.
[0010]
The electric motor 9 includes a stator 14 fixed to the caliper main body 3 and a hollow rotor 17 rotatably supported by the caliper main body 3 by bearings 15 and 16, and is connected to a controller (FIG. (Not shown), the rotation position is detected by a resolver 19 mounted on the rotor 17, and the rotor 17 can be rotated by a desired angle.
[0011]
In the differential reduction mechanism 10, a hollow eccentric shaft 20 is formed integrally with a rotor 17 of the electric motor 9, and a cylindrical external gear member 21 is rotatably mounted on the outer periphery of the eccentric shaft 20 via a bearing 22. Have been. The external gear member 21 has input-side external teeth 23 and output-side external teeth 24 formed on both axial sides. A fixed ring gear 25 having internal teeth that mesh with the input-side external teeth 23 of the external gear member 21 is fixed to the caliper body 3 by bolts 26. The output-side external teeth 24 are meshed with the internal teeth of a ring gear 28 formed integrally with the rotating disk 27 of the ball ramp mechanism 12.
[0012]
Here, as the number of teeth Z1 of the input-side external teeth 23 of the external gear member 21, the number of teeth Z2 of the internal teeth of the fixed ring gear 25, the number of teeth Z3 of the output-side external teeth 24, and the number of teeth Z4 of the internal gear of the ring gear 28, In the present embodiment, the number of teeth Z1 of the input-side external teeth 23 is made equal to the number of teeth Z2 of the fixed ring gear 25 (Z1 = Z2), and the rotation of the eccentric shaft 20 causes the input-side external teeth 23 to revolve without rotating. It is supposed to.
[0013]
The ball ramp mechanism 12 is opposed to a rotating disk 27 rotatably supported by the caliper body 3 by a bearing 29 (axial bearing) and fixed in the axial direction, and a linear disk 30 movably supported in the axial direction. The ball grooves 31 and 32 (inclined grooves) are formed as described above, and a ball 33 as a rolling element is inserted between the ball grooves 31 and 32. When the rotating disk 27 rotates, the balls 33 roll in the inclined ball grooves 31 and 32, so that the linear motion disk 30 moves in the axial direction according to the rotation angle of the rotating disk 27.
[0014]
The pad wear compensation mechanism 13 is integrally connected to a limiter 34 for restricting the relative rotation of the rotor 17 of the electric motor 9 and the translation disk 30 to a fixed amount, and the limiter 34 and the cylindrical portion 30a of the translation disk 30. The spring holder 35 is connected to a spring holder 35 by a coil spring 36 which is elastically connected to the spring holder 35. Thereby, the rotational force of the rotor 17 is transmitted to the linear motion disk 30, and when the brake pads 5 and 6 are worn and a gap is formed between the piston 11 and the brake pad 5, 6, the linear motion disk 30 is rotated. The piston 11 is advanced by the adjusting screw 37 between the brake pad 5 and the piston 11 to adjust the change in the pad clearance caused by the wear of the brake pads 5 and 6.
[0015]
A sensor unit 38 (detection means) is attached to the tip of the claw 4. The sensor unit 38 includes a bottomed cylindrical case 39, a piston member 40 slidably fitted in the case 39, a strain plate 41 (strain member) provided in the case 39, And a strain gauge 42 (strain detecting means) mounted on the strain plate 41.
[0016]
The case 39 is fitted to the tip of the claw 4 formed in a forked shape, and the flange 43 protruding outside the open end of the case 39 abuts on a step 44 formed on the claw 4 side. The cylinder bore 45, which is supported in the axial direction and in which the piston member 40 is fitted, is arranged concentrically with the piston 11 on the caliper body side. One end of the piston member 40 fitted in the cylinder bore 45 projects from the inner surface of the claw portion 4 and abuts against the back metal of the brake pad 6, and the claw portion 4 presses the brake pad 6 via the piston member 40. It has become. The other end of the piston member 40 is formed in a spherical shape, and its tip abuts on the center of the strain plate 41. The space between the piston member 40 and the cylinder bore 45 is sealed by an O-ring 46 to prevent foreign matter from entering the case 39.
[0017]
The strain-flexing plate 41 is supported in the axial direction by abutting on support portions 47 (step portions) formed on both sides of the bottom in the case 39, and when pressed by the piston member 40, is kept constant by the pressing force. Bending deformation. A strain gauge 42 is mounted on the surface of the strain generating plate 41 opposite to the contact portion of the piston member 40, and the strain gauge 42 detects bending deformation of the strain generating plate 41. The signal line 48 connected to the strain gauge 42 is wired along a groove formed on the surface of the claw portion 4, extends to the connector 18, and is connected to the controller via the connector 18.
[0018]
Next, the operation of the present embodiment configured as described above will be described.
At the time of braking, the controller detects the driver's brake pedal depression force (or displacement amount) by a brake pedal sensor, and based on the detected value, applies a drive voltage to the electric motor 9 of the electric disc brake 1 of each wheel by a driver circuit. Output, and rotates the rotor 17 by a predetermined rotation angle with a predetermined torque. The rotation of the rotor 17 is reduced at a predetermined reduction ratio by the differential reduction mechanism 10, converted into linear motion by the ball ramp mechanism 12, and advances the piston 11. One of the brake pads 5 is pressed by the disk rotor 2 by the piston 11, and the caliper main body 3 is moved along the slide pin 8 of the carrier 7 by the reaction force of the brake pad 5. The brake pad 6 is pressed against the disk rotor 2.
[0019]
At this time, a bending force is generated in the strain plate 41 due to the reaction force of the piston member 40 pressing the brake pad 6. By detecting the bending deformation by the strain gauge 42 and feeding back the output signal of the strain gauge 42 to the controller, an appropriate piston thrust can be obtained in accordance with a braking force request (brake pedal depression force) from the driver. The braking force can be controlled accurately.
[0020]
At the time of braking release, the electric motor 9 is rotated in the reverse direction to retract the piston 11, and the brake pads 5 and 6 are separated from the disk rotor 2 to release the braking.
[0021]
The controller uses various sensors to detect vehicle conditions such as the rotational speed of each wheel, vehicle speed, vehicle acceleration, steering angle, vehicle lateral acceleration, and the like, and controls the rotation of the electric motor 9 based on these detections. Accordingly, boost control, antilock control, traction control, vehicle stabilization control, and the like can be executed.
[0022]
By arranging the sensor unit 38 on the side of the claw portion 4 where a space is more easily secured than on the side of the caliper main body, the degree of freedom in the layout of each portion can be increased. Since the bending deformation of the strain generating plate 41 is slight and the claw portion 4 has no movable portion between the strain gauge 42 and the connector 18, it is not necessary to bend the signal line 48 almost and the wiring space is reduced. It is small and can be easily wired. By arranging the sensor unit 38 on the claw 4 side, it is possible to detect the drag of the brake pad 6 on the claw 4 side due to the poor sliding of the slide pin 8, and it is possible to know the maintenance time of the slide pin.
[0023]
In the first embodiment, the space between the piston member 40 and the cylinder bore 45 is sealed by the O-ring 46 to prevent foreign matter from entering the case 39. It can also be filled with synthetic resin, grease or the like to prevent foreign matter from entering.
[0024]
In the first embodiment, the bending deformation of the strain plate 41 is detected by the strain gauge 42. However, the strain plate 41 is brought into contact with the bottom of the case 39, and the strain gauge 42 is The strain gauge 42 may be attached to the side surface in the axial direction, and the strain gauge 42 may detect the compressive deformation of the strain generating plate 41 in the axial direction due to the reaction force from the brake pad 6.
[0025]
Next, a second embodiment of the present invention will be described with reference to FIGS. In the following description, the same parts as those in the first embodiment are denoted by the same reference numerals, and only different parts will be described in detail.
[0026]
As shown in FIG. 3, in the second embodiment, the sensor unit 49 directly supports both ends of the strain plate 50 by the steps of the claws 4 via the case 51, and attaches the predetermined portions to the back metal of the brake pad 6. The two convex portions 52 are formed with an interval of, the piston member is omitted, and the strain plate 50 is directly pressed by the two convex portions 52 of the back metal of the brake pad 6.
[0027]
With this configuration, similarly to the first embodiment, the strain gauge 42 can detect the bending deformation generated in the strain generating member 50 by the reaction force of the pressing force of the brake pad 6. At this time, as shown in FIG. 4A, the strain generating plate 50 is a simple beam, the load (concentrated load) by the convex portion 52 is W1, W2, the fulcrum reaction force of the step portion 44 of the claw portion 4 is R1, Assuming that R2, the BMD (bending moment diagram) is as shown in FIG. 4B, and the bending moment generated between the portions of the strain-causing plate 50 where the two loads W1, W2 act is uniform. I understand. Therefore, the bending deformation generated between the contact portions of the two convex portions 52 in the strain plate 50 becomes uniform, and the strain gauge 42 determines the distance between the contact portions of the two convex portions 52 in the strain plate 50. The strain gauge 42 may be mounted at the position, and the strain gauge 42 can be easily positioned.
[0028]
Next, a third embodiment of the present invention will be described with reference to FIGS. In the following description, the same parts as those in the second embodiment are denoted by the same reference numerals, and only different parts will be described in detail.
[0029]
As shown in FIG. 5, in the present embodiment, the height of the two convex portions 52 of the brake pad 6 is large, and the strain amplifying plate 50 is provided between the contact portions of the two convex portions 52 of the strain generating plate 50. 53 are attached. As shown in FIG. 6, the strain amplification plate 53 is formed by bending a plate material into a convex shape, and the rigidity of the two legs 54 connected to the strain generating plate 50 connects the legs 54 to each other. The rigidity of the top 55 is higher than that of the top 55, and the strain gauge 42 is attached to the center of the top 55.
[0030]
With this configuration, similarly to the second embodiment, when bending occurs in the strain generating plate 50 due to the reaction force from the brake pad 6, bending occurs in the top 55 of the strain amplifying plate 53. By detecting the bending deformation of 55 by the strain gauge 42, the reaction force of the brake pad 6 can be obtained.
[0031]
At this time, as shown in FIG. 6, when bending deformation occurs in the strain generating plate 50, the leg 54 of the strain amplification plate 53 is inclined by an angle θ, and the length a of the leg 54 causes the apex 55 to have a distance 2a · As a result of the compression by sin θ, bending deformation occurs at the top 55, and the strain detected by the strain gauge 42 is amplified with respect to the bending deformation of the strain generating plate 50. Thereby, it is possible to improve the detection accuracy of the bending deformation. For the same reason as in the second embodiment, the bending moment acting between the abutting portions of the two convex portions 52 of the strain plate 50 becomes uniform. Any location between the contact portions of the two convex portions 52 may be used.
[0032]
In the first to third embodiments, the case where the present invention is applied to an electric disc brake is described as an example. However, the present invention is not limited to this, and the brake pad is pressed via a claw. If it is a caliper floating type disc brake, it can be similarly applied to a hydraulic disc brake.
[0033]
【The invention's effect】
As described above in detail, according to the disk brake of the first aspect of the present invention, the pressing force of the brake pad against the disk rotor can be detected by the detecting means provided on the claw side, and the space on the claw side can be detected. Can be effectively used, and since the detecting means does not move with respect to the caliper, wiring to the detecting means is facilitated.
According to the disk brake of the second aspect of the present invention, it is possible to obtain the pressing force of the brake pad against the disk rotor based on the distortion of the strain generating member detected by the distortion detecting means.
According to the disk brake of the third aspect of the present invention, it is possible to obtain the pressing force of the brake pad against the disk rotor based on the bending deformation of the strain plate detected by the strain gauge.
According to the disk brake of the fourth aspect of the present invention, since the bending moment generated in the strain plate by the reaction force from the brake pad becomes uniform between two points receiving the reaction force from the brake pad, the strain is increased. The gauge can be easily positioned.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a disc brake according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the disc brake shown in FIG.
FIG. 3 is a cross-sectional view showing a main part of a disc brake according to a second embodiment of the present invention.
FIG. 4 is a diagram showing a bending moment generated in a strain plate of the disc brake shown in FIG. 3;
FIG. 5 is a cross-sectional view showing a main part of a disc brake according to a third embodiment of the present invention.
FIG. 6 is an enlarged view showing a state where the strain amplification plate of the device shown in FIG. 5 is deformed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electric disc brake 2 Disc rotor 4 Claw part 5, 6 Brake pad 7 Carrier 11 Piston 38 Sensor unit (detection means)
41,50 strain plate (strain member)
42 Strain gauge (strain detecting means)

Claims (4)

A caliper floating type having a caliper having a piston opposed to one of brake pads arranged on both sides of a disc rotor and a claw straddling the disc rotor and facing the other of the brake pads movably supported by a carrier. In the disc brake,
A disc brake, wherein a detecting means for detecting a pressing force of the brake pad against the disc rotor is provided on the claw portion. The detecting means includes a strain generating member that deforms by receiving a reaction force of a pressing force of the brake pad against the disk rotor, and a strain detecting means that detects a strain of the strain generating member. The disc brake according to claim 1, wherein The strain generating member is a strain generating plate that is provided between the brake pad and the claw portion and generates bending deformation by a reaction force from the brake pad. 3. The disc brake according to claim 2, wherein the disc brake is a strain gauge mounted. The strain generating plate receives a reaction force from the brake pad at two points, and the strain gauge is mounted between two points of the strain generating plate receiving the reaction force from the brake pad. The disc brake according to claim 3.

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