JP2015021508A - Wear amount detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure wear amounts of a brake pad and a disc rotor in a disc brake of a vehicle.SOLUTION: A wear amount detection device which detects wear amounts of a disc rotor and a brake pad in a disc brake of a vehicle comprises: the disc rotor; the brake pad; an electric piston which is driven by an electric motor, and makes the brake pad contact the disc rotor; contact detection means 80 which detects the contact; piston stroke amount detection means 90 which detects a piston stroke amount of the electric piston; brake detection means 50 which detects that a brake operation is performed; and a calculation part 60 which calculates the wear amounts of the disc rotor and the brake pad from a difference between the piston stroke amount in assembling and the piston stroke amount in use.

Description

  The present invention relates to a wear amount detecting device for detecting the wear amount of a brake pad and a disc rotor in a disc brake of an automobile.

  In an automobile, a disc brake is often used as one of brake devices (particularly, a foot brake). The disc brake presses a brake pad against a disc rotor that rotates together with an axle, and brakes the vehicle by a frictional force between the disc rotor and the brake pad.

  Generally, a hydraulic disc brake is used as a disc brake in an automobile. The hydraulic disc brake is equipped with a hydraulic piston in a U-shaped caliper installed so as to surround a part of the disc rotor, and the piston and caliper are moved by hydraulic pressure, and the brake pad and caliper provided at the piston tip This is a mechanism for sandwiching the disc rotor between brake pads provided on the disc.

  In the hydraulic disc brake, since the pressing force of the brake pad, that is, the braking force of the vehicle is controlled by the hydraulic pressure, a sensor capable of measuring the piston stroke is not attached. Therefore, the amount of wear in the brake pad and the disk rotor is inspected at the time of inspection such as vehicle inspection.

JP 2006-105224 A

  However, when the vehicle inspection interval is increased, wear of the brake pads and the disc rotor proceeds, and there is a possibility that the brake pads and the disc rotor are worn beyond a predetermined allowable value.

  In addition, there exists a thing of patent document 1 as a means to measure the abrasion amount of the disk in a brake. The technology described in Patent Document 1 detects the origin position of the piston and the contact position with the disk from the motor rotation angle of the electric motor that operates the piston that presses the disk when the aircraft brake system is started in the aircraft brake. An electric brake that calculates a disc wear amount and adjusts a disc gap between the disc and the piston, but does not measure a brake pad corresponding to a tip of a piston portion of a disc brake in an automobile.

  The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to measure the wear amount of a brake pad and a disc rotor in a disc brake of an automobile.

  A wear amount detection device according to a first invention for solving the above-described problems is operated by a disk rotor that rotates together with an axle of an automobile, a brake pad that obtains braking energy of the vehicle by contacting the disk rotor, and an electric motor. An electric piston for bringing the brake pad into contact with the disk rotor; contact detecting means for detecting the contact; and the electric piston moving from a predetermined position to a position where contact is detected by the contact detecting means. Detected by the piston stroke amount detecting means for detecting the piston stroke amount, the brake detecting means for detecting that the brake operation has been performed, and the piston stroke amount detecting means when the disc rotor or the brake pad is assembled. Piston stroke amount, and the disk rotor The wear amount of the disc rotor and the brake pad is calculated from the difference from the piston stroke amount detected by the piston stroke amount detecting means when the brake operation is detected by the brake detecting means in order to use the brake pad. And an arithmetic unit for performing the processing.

  A wear amount detection device according to a second invention for solving the above-described problems is the wear amount detection device according to the first invention. The pad wear amount of the brake pad is calculated from the difference between the wear amount of the disk rotor and the brake pad and the rotor wear amount of the disk rotor.

  The wear amount detection device according to a third aspect of the present invention that solves the above problem is the wear amount detection device according to the second aspect of the invention, wherein the rotor wear amount of the disk rotor in the computing unit is based on the total travel distance of the automobile. Or based on the cumulative number of brakes of the automobile or both.

  The wear amount detection device according to a fourth invention for solving the above-mentioned problems is the wear amount detection device according to any one of the first to third inventions, wherein the piston stroke amount detection means is the electric motor in the electric piston. This is a motor rotation angle sensor for detecting the motor rotation angle.

  The wear amount detection device according to a fifth aspect of the present invention that solves the above-described problem is the wear amount detection device according to any one of the first to fourth aspects, wherein the contact detection means applies the electric piston to the brake pad. It is a load sensor for detecting a load.

  According to the wear amount detecting device according to the first aspect of the present invention, there is provided a wear amount detecting device capable of measuring the wear amount of a part worn by friction or the like in an automobile disc brake, when the disc rotor or the brake pad is assembled. The amount of wear of the disc rotor and brake pad is calculated from the difference between the piston stroke amount of the piston and the piston stroke amount when the brake operation is detected by the brake detection means in order to use the disc rotor and brake pad. The wear amount of the disc rotor and the brake pad can be measured even during traveling in which the brake operation can be performed, not only when checking the vehicle or starting the engine.

  According to the wear amount detection device of the second invention, the calculation unit predicts the wear amount of the disc rotor, and the brake pad wear is determined from the difference between the wear amount of the disc rotor and the brake pad and the wear amount of the rotor of the disc rotor. By calculating the amount, the wear amount of the brake pad can be accurately measured.

  According to the wear amount detection device of the third invention, the wear amount of the disk rotor in the calculation unit is based on the total travel distance of the vehicle, based on the cumulative number of brakes of the vehicle, or both. Therefore, it is possible to accurately measure the wear amount of the brake pad.

  According to the wear amount detection device of the fourth invention, as a piston stroke amount detection means, a motor rotation angle sensor that is normally equipped to detect the motor rotation angle of an electric motor in an electric piston is used, and a new Since there is no need to add a new component, an increase in manufacturing cost can be suppressed.

  According to the wear amount detection device of the fifth aspect of the present invention, a new component is added by using a load sensor that is normally equipped to detect the load applied to the brake pad by the electric piston as the contact detection means. Therefore, it is possible to suppress an increase in manufacturing cost.

It is a block diagram which shows the control in the abrasion amount detection apparatus which concerns on Example 1. FIG. 3 is a flowchart illustrating control in the wear amount detection apparatus according to the first embodiment. It is explanatory drawing which shows the stand-by position at the time of a new disc rotor and brake pad in a disc brake provided with the abrasion amount detection apparatus which concerns on Example 1. FIG. It is explanatory drawing which shows the brake position at the time of a new disc rotor and brake pad in a disc brake provided with the abrasion amount detection apparatus based on Example 1. FIG. It is explanatory drawing which shows the stand-by position at the time of disk rotor and brake pad abrasion in the disk brake provided with the abrasion amount detection apparatus which concerns on Example 1. FIG. It is explanatory drawing which shows the braking position at the time of disk rotor and brake pad abrasion in the disk brake provided with the abrasion amount detection apparatus which concerns on Example 1. FIG. It is explanatory drawing which shows the example from which the press structure of a brake pad differs from the disc brake provided with the abrasion amount detection apparatus which concerns on Example 1. FIG. It is explanatory drawing which shows the example from which the disc brake provided with the abrasion amount detection apparatus based on Example 1 and FIG. 7 differ in the press structure of a brake pad. FIG. 9 is an explanatory diagram showing an example of a brake pad pressing structure different from that of the disc brake including the wear amount detection device according to the first embodiment and FIGS. 7 and 8.

  Hereinafter, embodiments of a wear amount detection device according to the present invention will be described in detail with reference to the accompanying drawings. Needless to say, the present invention is not limited to the following examples, and various modifications can be made without departing from the spirit of the present invention.

  A structure and a brake mechanism of a disc brake provided with a wear amount detection device according to Embodiment 1 of the present invention will be described with reference to FIG.

  As shown in FIG. 3, the disc brake 1 provided with the wear amount detecting device according to the present embodiment is fixed to a wheel shaft (not shown) and rotates with the wheel shaft, and a frame (not shown). A caliper 20 having a U-shaped cross section that is supported so as to surround a part of the disk rotor 10 from the outer peripheral side, and the inner side (the disk rotor 10 side, that is, the left end portion in FIG. 3) 21 of the caliper 20. The electric piston 30 having a piston connected to the right side in FIG. 3 and movable in the wheel axis direction (left-right direction in FIG. 3), and a wear amount detection device to be described later.

  The electric piston 30 in the present embodiment includes an electric motor 31 and a piston mechanism (not shown) connected to the electric motor 31 and a cylindrical cylinder portion 32 having a central axis in the same direction as the wheel shaft (left and right direction in FIG. 3). A first piston portion 33 that is gripped by the cylinder portion 32 and is movable from the cylinder portion 32 to the disk rotor 10 side (right side in FIG. 3), and a gripper that is gripped by the cylinder portion 32 and that moves from the cylinder portion 32 to the disk rotor 10. And a second piston part 34 that can move to the opposite side (the opposite side of the first piston part 33, that is, the left side in FIG. 3).

  A brake pad 40 that makes contact with or separates from the disk rotor 10 is provided at the tip end portion (the end portion on the disk rotor 10 side, that is, the right side end portion in FIG. 3) 35 of the first piston portion 33 of the electric piston 30. Installed. Since the electric motor 31 and the cylinder part 32 of the electric piston 30 are fixed to the vehicle body via a mounting port (not shown), the brake pad 40 is moved by the movement of the first piston part 33 in the electric piston 30, When pressed against one side surface 10a of the disc rotor 10, a frictional force is generated, and braking energy of the vehicle is obtained.

  A tip end portion (an end portion opposite to the disk rotor 10, that is, a left side end portion in FIG. 3) 36 of the second piston portion 34 of the electric piston 30 is connected to the inside of the one end portion 21 of the caliper 20. On the other hand, on the inner side (the disc rotor 10 side, that is, the left side in FIG. 3) 22 of the other end portion (right end portion in FIG. 3) of the caliper 20, there is a brake pad 41 that contacts or separates from the disc rotor 10. Installed. As described above, since the electric motor 31 and the cylinder part 32 of the electric piston 30 are fixed to the vehicle body, the caliper 20 connected to the second piston part 34 by the movement of the second piston part 34 in the electric piston 30 and The brake pad 41 is moved and pressed against the other side surface 10b of the disc rotor 10 to generate a frictional force, thereby obtaining vehicle braking energy.

  When the driver steps on a brake pedal (not shown), the electric motor 31 is operated in the forward direction. The shaft rotational motion of the electric motor 31 is converted into linear motion in the wheel shaft direction (left-right direction in FIG. 3) by a piston mechanism (not shown) built in the cylinder portion 32. By this linear motion, the first piston part 33 is moved to the disk rotor 10 side, and the second piston part 34 is moved to the side opposite to the disk rotor 10.

  The brake pad 40 provided at the distal end portion 35 of the first piston portion 33 comes into contact with the side surface 11 a of the disk rotor 10 by the movement of the first piston portion 33, and the brake pad provided inside the other end portion 22 of the caliper 20. 41 is brought into contact with the side surface 11 b of the disk rotor 10 by the movement of the caliper 20 by the movement of the second piston portion 34. Therefore, the disc rotor 10 is sandwiched between the brake pads 40 and 41 to generate a frictional force, and a braking force acts on the vehicle.

  On the other hand, when the driver removes his / her foot from a brake pedal (not shown), the electric motor 31 is operated in the reverse direction. The shaft rotation motion in the reverse direction of the electric motor 31 is converted into linear motion in the wheel shaft direction (left-right direction in FIG. 3) by a piston mechanism (not shown) in the cylinder portion 32. By this linear motion, the first piston part 33 is moved to the side opposite to the disk rotor 10, and the second piston part 34 is moved to the disk rotor 10 side.

  The brake pad 40 provided at the distal end portion 35 of the first piston portion 33 is separated from the side surface 11 a of the disk rotor 10 by the movement of the first piston portion 33, and the brake pad provided inside the other end portion 22 of the caliper 20. 41 moves away from the side surface 11 b of the disk rotor 10 when the caliper 20 moves due to the movement of the second piston portion 34. Therefore, the frictional force between the disc rotor 10 and the brake pads 40 and 41 disappears, and the braking force does not act on the vehicle.

  In the present embodiment, the piston mechanism (not shown) built in the cylinder portion 32 of the electric motor 31 is driven by the first piston portion 33 and the axial rotation motion of the electric motor 31 in the positive direction at the rotational angular velocity ω [rad / s]. The second piston part 34 is moved (elongated) in the direction away from each other at the same moving speed v [mm / s], and the first axial movement of the electric motor 31 at the rotational angular speed −ω [rad / s] is reversed. The one piston part 33 and the second piston part 34 are moved (atrophyed) in directions approaching at the same moving speed v [mm / s].

  Here, the coefficient A [mm / rad] is used for the relationship between the rotational angular velocity ω [rad / s] of the electric motor 31 and the moving speed v [mm / s] of the first piston portion 33 and the second misting portion 34. Is represented by the following formula (1).

  v [mm / s] = ω [rad / s] × A [mm / rad] (1)

  Next, the configuration of the wear amount detection device and the measurement of the wear amount according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 3 to 6.

As shown in FIG. 1, the wear amount detection device according to the present embodiment includes a wear amount detection start trigger unit 50 that detects the timing of measuring the wear amount, and the wear amounts of the brake pads 40 and 41 (hereinafter, this specification). In this case, W _P [mm] (referred to as pad wear amount) and wear amount (hereinafter referred to as rotor wear amount) W _R [mm] of the disk rotor 10 are measured and whether or not a warning is required for the measurement result is required. , A load sensor 80 and a motor rotation angle sensor 90 used for calculation of the pad wear amount W _P [mm] in the pad wear amount measurement unit 70 of the calculation unit 60, and the rotor wear of the calculation unit 60. a rotor wear amount W _R travel distance detecting unit 110 and the brake frequency storage unit 120 is used to calculate the [mm] in the amount measuring unit 100, the arithmetic unit 60 warning determination section 130 And a display unit 140 for displaying a warning by definitive warning indication.

In the present embodiment, the wear amount detection start trigger unit 50 is used as a brake detection unit that detects that a brake operation has been performed using a brake pedal (not shown), and the brake pedal is depressed more than a predetermined value by the driver. In this case, the measurement of the pad wear amount W _P [mm] is started.

  The load sensor 80 and the motor rotation angle sensor 90 are used as contact position detection means for detecting positions where the brake pads 40 and 41 are in contact with the disk rotor 10. Specifically, the load sensor 80 is a means for detecting contact between the brake pads 40 and 41 and the disk rotor 10, and is a contact in which the brake pads 40 and 41 are brought into contact with or separated from the disk rotor 10 by the electric piston 30. Used as timing detection means (contact detection means) for detecting the separation timing, the motor rotation angle sensor 90 is a means for detecting the piston stroke of the electric piston 30, and the electric piston 30 is detected from a predetermined position by the contact detection means. This is used as a piston stroke amount detecting means for detecting the piston stroke amount that has moved to the position where contact is detected. The contact position detection by the load sensor 80 and the motor rotation angle sensor 90 will be described below.

  When the driver is not operating the brake, the brake pads 40 and 41 are in a standby position in a state of being separated from the disc rotor 10 (see FIG. 3), and a load is applied to the brake pads 40 and 41. No (pad load P = 0 [N] which is a detection value of the load sensor 80). When the driver performs a brake operation, the brake pads 40 and 41 are brought into contact positions with which the disk rotor 10 comes into contact (see FIG. 4), and a load is applied to the brake pads 40 and 41 (pad load P> 0). [N]). Furthermore, when the driver stops the brake operation, the brake pads 40 and 41 return to the standby position in a state of being separated from the disc rotor 10 (see FIG. 3), and the brake pads 40 and 41 are again loaded. (Pad load P = 0 [N]).

In this embodiment, when the load P applied to the brake pads 40 and 41 is released, that is, when the pad load P = 0 [N], the rotation angle detected by the motor rotation angle sensor 90 is used as the reference motor. A rotation angle θ [rad] is assumed. Then, the time of assembling the disc rotor 10 and brake pads 40 and 41 (FIGS. 3 and 4) reference motor rotational angle theta reference motor rotational angle during assembly the [rad] θ _a [rad] of the disk rotor 10 and the brake pads 40 and 41 (FIGS. 5 and 6) are set to the reference motor rotation angle θ _b [rad] during wear. The position where the motor rotation angle is 0 degrees (predetermined position) is, for example, the position where the brake pads 40 and 41 are farthest from the disc rotor 10.

  Here, when the disc rotor 10 and the brake pads 40 and 41 are assembled, it is immediately after the disc rotor 10 and the brake pads 40 and 41 are assembled to the disc brake 1, and the vehicle is in a state of a new vehicle, or This includes a state in which the disk rotor 10 and the brake pads 40 and 41 are replaced due to wear or the like. Of course, not only the state in which both the disk rotor 10 and the brake pads 40 and 41 are replaced at the same time, but also a state in which only one of the disk rotor 10 and the brake pads 40 and 41 is replaced.

The difference between the new reference motor rotation angle θ _a [rad] and the worn reference motor rotation angle θ _b [rad] is the piston stroke when the electric piston 30 is assembled due to wear of the disc rotor 10 and the brake pads 40 and 41. This is the difference between the amount and the piston stroke amount during use, and is the total wear amount (wear amount) W [mm] of the disk rotor 10 and the brake pads 40 and 41. Therefore, when the disc rotor 10 or the brake pads 40 and 41 are assembled, the piston stroke amount detected by the piston stroke amount detection means and the brake detection means for using the disc rotor 10 and the brake pads 40 and 41 are braked by the brake detection means. The amount of wear of the disc rotor 10 and the brake pads 40 and 41 is calculated from the difference from the piston stroke amount detected by the piston stroke amount detection means when the operation is detected. In this embodiment, the calculation unit 60 uses the coefficient A [mm / rad] similarly to the equation (1), and the total wear amount W [mm] of the disc rotor 10 and the brake pads 40 and 41 according to the following equation (2). ] Is calculated.

W [mm] = (W _P + W _R ) [mm]
= (Θ _b −θ _a ) [rad] × A [mm / rad] (2)

The disk rotor 10 is made of a material harder than the brake pads 40 and 41, and the rotor wear amount W _R [mm] is smaller than the pad wear amount W _P [mm]. In the present embodiment, the rotor wear amount W _R [mm] is set to the total travel distance D [km] of the vehicle indicating the vehicle state of the automobile or the number of times of use of the disc brake 1 (hereinafter, the cumulative number of brakes in this specification). It is estimated roughly by n [times].

The relationship between the total travel distance D [km] and the rotor wear amount W _R [mm] detected by the travel distance detection unit 110 is expressed by the following expression (3) using the coefficient B. Incidentally, the predicted value of the total travel distance D rotor wear amount calculated from _{[km] W R [mm]} , and rotor wear amount W _R1 [mm].

W _R1 [mm] = D [mm] × B (3)

Further, the relationship between the cumulative number of brakes n [times] and the rotor wear amount W _R [mm] is expressed by the following equation (4) using a coefficient C [mm / times]. Incidentally, the predicted value of the accumulated brake count n [times] rotor wear amount obtained from W _R [mm], and rotor wear amount W _R2 [mm].

W _R2 [mm] = n [times] × C [mm / times] (4)

In this embodiment, the larger one of W _R1 [mm] or W _R2 [mm] obtained above is selected and adopted as the rotor wear amount W _R [mm]. Therefore, an accurate pad is obtained from the total wear amount W [mm] of the disc rotor 10 and the brake pads 40 and 41 obtained by the equation (2) and the W _R [mm] obtained by the equation (3) or the equation (4). The wear amount W _P [mm] is obtained by the following equation (5).

W _P [mm] = W [mm] −W _R [mm] (5)

In this embodiment, the distance α between the disc rotor 10 and the brake pads 40 and 41 is set to be constant in order to make the time during which the braking force is applied to the vehicle from the driver's braking operation constant. This distance α is obtained by operating the electric motor 31 in the reverse direction by the amount corresponding to the shaft rotational movement of the predetermined motor rotational speed from the new reference motor rotation angle θ _a [rad] or the worn reference motor rotation angle θ _b [rad]. Is set by

  Next, control of wear amount measurement in the disc brake 1 provided with the wear amount detection device according to the first embodiment of the present invention will be described with reference to FIGS.

  First, in step S1, it is determined whether or not detection of the wear amount of the disk rotor 10 and the brake pads 40 and 41 should be started. In the present embodiment, when the driver steps on a brake pedal (not shown) as the wear amount detection start trigger unit 50, detection of the wear amount of the disc rotor 10 and the brake pads 40 and 41 should be started. It is assumed that the wear amount of the disc rotor 10 and the brake pads 40 and 41 should not be detected when the person is not stepping on the brake pedal.

  When it is determined in step S1 that the driver should step on a brake pedal (not shown) as the wear amount detection start trigger unit 50 and start detection of the wear amount of the disc rotor 10 and the brake pads 40 and 41. The process proceeds to step S2. If it is determined in step S1 that the driver does not step on the brake pedal and the wear amount of the disc rotor 10 and brake pads 40 and 41 should not be started, the process returns to step S1 again.

  Next, in step S2, it is determined whether or not the load sensor 80 and the motor rotation angle sensor 90 are operating normally. In this embodiment, it is determined whether or not the load sensor 80 and the motor rotation angle sensor 90 are stuck to the maximum value or the minimum value. That is, if the motor rotation angle sensor 90 does not detect the displacement of the motor rotation angle θ [rad] despite the electric motor 30 being operated, it is determined that the motor rotation angle sensor 90 is not operating normally. If the load sensor 80 does not detect the displacement of the pad load P even though the electric motor 30 is operated to increase the motor rotation angle θ [rad] to a predetermined value or more, the load sensor 80 operates normally. It is judged that it is not.

  If it is determined in step S2 that the load sensor 80 and the motor rotation angle sensor 90 are operating normally, the process proceeds to step S3. When it is determined that the load sensor 80 and the motor rotation angle sensor 90 are not operating normally, the process returns to step S1 again.

  Next, in step S3, it is determined whether or not the pad load P [N] is greater than or equal to a predetermined value Q [N]. In this embodiment, the pad load P [N] is measured by the load sensor 80, and the pad load P [N] by the load sensor 80 is compared with a predetermined value Q [N].

  If it is determined in step S3 that the pad load P [N] is equal to or greater than the predetermined value Q [N] (P ≧ Q), the process proceeds to step S4. If it is determined in step S3 that the pad load P [N] is not equal to or greater than the predetermined value Q [N] (P <Q), the process returns to step S1 again. The predetermined value Q [N] is preferably set to a value that is not likely to be detected by the load sensor 80 due to vehicle vibration or inertia when the electric piston 30 is operated.

  Next, in step S4, it is determined whether or not the motor rotation angle θ [rad] is greater than or equal to a predetermined value R [rad]. In the present embodiment, the motor rotation angle θ [rad] is measured by the motor rotation angle sensor 90, and the motor rotation angle θ [rad] by the motor rotation angle sensor 90 is compared with a predetermined value R [rad].

If it is determined in step S4 that the motor rotation angle θ [rad] is equal to or greater than the predetermined value R [rad] (θ ≧ R), the process proceeds to step S5. If it is determined in step S4 that the motor rotation angle θ [rad] is not equal to or greater than the predetermined value R [rad] (θ <R), the process returns to step S1 again. The predetermined value R [rad] is preferably a previously measured new reference motor rotation angle θ _a [rad] or a worn reference motor rotation angle θ _b [rad].

Next, in step S5, the rotor wear amount W _R [mm] and the pad wear amount W _P [mm] are measured. In step S5, the rotor wear amount W _R [mm] is calculated by the rotor wear amount measuring unit 100 in the calculation unit 60, and the pad wear amount W _P [mm] is calculated by the pad wear amount measuring unit 70 in the calculation unit 60. .

In the present embodiment, the rotor wear amount W _R [mm] is expressed by Equations (3) and (4), that is, the total travel distance D [km] of the vehicle indicating the vehicle state of the automobile and the cumulative number of brakes n [times]. ], The rotor wear amounts W _R1 , W _R2 [mm] are calculated, and the larger one of W _R1 [mm] or W _R2 [mm] is selected and set as the rotor wear amount W _R [mm]. Further, from the difference between the new reference motor rotation angle θ _a [rad] and the wear reference motor rotation angle θ _b [rad], the total wear amount W [of the disc rotor 10 and the brake pads 40 and 41 is calculated by the equation (2). mm] is calculated, and an accurate pad wear amount W _P [mm] is calculated by substituting the rotor wear amount W _R [mm] into the equation (5).

Next, in step S6, it is determined whether the rotor wear amount W _R [mm] is equal to or greater than a predetermined value W _A [mm], or the pad wear amount W _P [mm] is equal to or greater than a predetermined value W _B [mm]. Judge whether there is. Here, the predetermined value W _A [mm] and the predetermined value W _B [mm] are set so as to conform to a standard determined by a vehicle inspection or the like.

In step S6, if the rotor wear amount W _R [mm] is not less than the predetermined value W _A [mm] or the pad wear amount W _P [mm] is not less than the predetermined value W _B [mm], in step S7. A warning is displayed and the process returns to step S1 again. In step S6, when the rotor wear amount W _R [mm] is less than the predetermined value W _A [mm] and the pad wear amount W _P [mm] is less than the predetermined value W _B [mm], it is left as it is. Return to step S1.

  By the above control, the wear amount is measured in the disc brake 1 provided with the wear amount detection device according to the present embodiment. The above-described wear amount measurement is performed not only at the time of inspection such as vehicle inspection, but also during driving of the vehicle, that is, during traveling. Therefore, according to the wear amount detection apparatus according to the present embodiment, it is possible to measure the wear amount of the disk rotor 10 and the brake pads 40 and 41 for each use, that is, in real time.

  In this embodiment, a so-called floating caliper structure is employed as a brake mechanism in the disc brake 1 provided with the wear amount detection device, but the present invention is not limited to this. For example, as shown in FIG. 7, the caliper 220 may be fixed to a frame (not shown) and the brake pad 40 may be pressed against the disc rotor 10 from one side by an electric piston. As shown in FIG. The brake pad 40 may be pressed against the disc rotor 10 by the piston 330a, and the brake pad 41 may be pressed against the disc rotor 10 by moving the caliper 320 by another electric piston 330b, as shown in FIG. The brake pads 40 and 41 may be pressed against the disc rotor 10 by the two electric pistons 430a and 430b, respectively. 7 to 9, the other constituent members are denoted by the same reference numerals as those shown in FIGS. 3 to 6.

This is the end of the description of the embodiment of the invention. However, the embodiment of the invention is not limited to this embodiment. In the present embodiment, the position where the motor rotation angle is 0 degrees is the position where the brake pad 40 is farthest from the disc rotor 10, but the position is not limited to this and may be an arbitrary position. Of course, the position at the time of assembly may be used as a reference.
Further, the predicted value of the amount of wear of the rotor is calculated based on the total travel distance of the vehicle or based on the cumulative number of brakes of the vehicle, but is not limited to this. For example, the usage time of the vehicle or a combination of these may be used.

DESCRIPTION OF SYMBOLS 1 Disc brake 10 Disc rotor 20 Caliper 30 Electric piston 31 Electric motor 32 Cylinder part 33 First piston part 34 Second piston part 35 First piston part tip part 36 Second piston part tip part 40 Brake pad 41 Brake pad 50 Wear amount detection start trigger unit 60 Calculation unit 70 Pad wear amount measurement unit 80 Load sensor 90 Motor rotation angle sensor 100 Rotor wear amount measurement unit 110 Travel distance detection unit 120 Brake count storage unit 130 Warning determination unit 140 Display unit

Claims (5)

A disk rotor that rotates with the axle of the car;
A brake pad for obtaining braking energy of the vehicle by contacting the disk rotor;
An electric piston operated by an electric motor to bring the brake pad into contact with the disk rotor;
Contact detection means for detecting the contact;
A piston stroke amount detecting means for detecting a stroke amount of movement of the electric piston from a predetermined position to a position where contact is detected by the contact detecting means;
Brake detecting means for detecting that a brake operation has been performed;
The piston stroke amount detected by the piston stroke amount detecting means when the disc rotor or the brake pad is assembled, and the brake operation is detected by the brake detecting means for using the disc rotor and the brake pad. A wear amount detecting device comprising: a calculation unit that calculates wear amounts of the disk rotor and the brake pad from a difference from a piston stroke amount detected by the piston stroke amount detecting means at the time. The calculation unit predicts a rotor wear amount of the disk rotor based on a vehicle state of the automobile, and calculates a brake pad amount based on a difference between a wear amount of the disk rotor and the brake pad and a rotor wear amount of the disk rotor. The wear amount detection device according to claim 1, wherein the wear amount of the pad is calculated. The rotor wear amount of the disk rotor in the calculation unit is calculated based on the total travel distance of the automobile, the cumulative number of brakes of the automobile, or both. The wear amount detection device according to claim 2, wherein The wear amount according to any one of claims 1 to 3, wherein the piston stroke amount detection means is a motor rotation angle sensor that detects a motor rotation angle of the electric motor in the electric piston. Detection device. The wear amount detection device according to any one of claims 1 to 4, wherein the contact detection means is a load sensor that detects a load applied by the electric piston to the brake pad.

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