JP3631272B2 - Disc brake pad wear detector - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a wear detection device that electrically detects wear of a lining of a disc brake pad and remotely notifies it.
[0002]
[Prior art]
The disc brake is configured so as to schematically show one example in FIGS. 10 is a side view, FIG. 11 is a cross-sectional view taken along the line AA in FIG. 10 excluding the support, and FIG. 12 is a plan view excluding a part of the caliper at the left end of FIG.
[0003]
Reference numeral 1 denotes a rotor that rotates in conjunction with a vehicle wheel, 2 a support that is fixed to the vehicle body, and 3 a caliper that is supported by a guide pin 4 that is fixed to the support 2 and that is movable in the rotor axial direction. . Pads 6 and 6 are provided on both sides of the rotor 1, and linings 6b attached to the back metal 6a are opposed to the rotor 1, respectively. The caliper 3 is formed with a cylinder 7 on one side of the rotor and fitted with a piston 8 facing one pad 6, and a claw 9 is formed on the other side of the rotor 1 to hold down the other pad 6. . Both ends of the backing metal 6a are movable in the rotor axial direction by engaging the inner end portions 10 and 10 of the support 2 with grooves. Illustration and description of the caliper 3 and the spring for preventing rattling between the pad back metal 6a and the support 2 are omitted.
[0004]
In FIG. 11, pressure oil is supplied to the cylinder 7 to push out the piston 8, and when the right pad 6 is pressed against the right side surface of the rotor 1, the caliper 3 moves to the right as the reaction, and the claw 9 moves to the left. One of the pads 6 is pressed against the left side surface of the rotor 1, the rotor 1 is braked by friction with the linings 6b, 6b of both pads 6, 6, and the wheels associated therewith are braked.
[0005]
When braking is repeated in this manner, the lining gradually wears and the pad must be replaced when lining wear progresses to an acceptable limit. In order to automatically notify the driver that the lining has been worn to an allowable limit even during operation, an electrical automatic wear detection device has been conventionally considered.
[0006]
FIG. 13 shows a contact type of such conventionally known automatic wear detectors, in which a resin piece 12 in which a loop-shaped conductor 11 is embedded is perforated with a back metal 6a and a lining 6b. The tip of the loop-shaped conductor 11 is positioned on the surface of the lining 6b with the allowable wear limit thickness L, and both ends of the loop-shaped conductor 11 are led to an indicator (not shown) by the conductor 13.
[0007]
When the lining 6b is worn to the allowable limit, the resin piece 12 is worn together with the lining 6b, and as the wear progresses, the loop conductor 11 is rubbed with the rotor and the conduction of the conductor 13 is cut off. An indicator will then indicate that the lining has worn to an acceptable limit and an alarm will be issued.
[0008]
FIG. 14 shows a non-contact type automatic wear detection device (refer to Japanese Patent Laid-Open No. 60-139930) different from the previous example, in which a sensor 14 that changes electrical output depending on the distance from a magnetic body is fixed to a caliper 3, and a lining When the 6b wears and the steel back metal 6a approaches the sensor 14, the output of the sensor 14 changes so that it can be detected that the lining is worn to an allowable limit.
[0009]
[Problems to be solved by the invention]
In the conventional electric wear detection device as described above, since the first contact type device embeds and fixes the resin piece 12 in the pad 6, it is necessary to change the lead wire 13 when replacing the pad, and the workability is poor. Since the resin piece 12 in which the loop-shaped conducting wire 11 is embedded is disposable, it is uneconomical. The second contactless device is similarly uneconomical because a sensor 14 is required for each pad 6.
[0010]
[Means for Solving the Problems]
The disc brake pad wear detection device of the present invention includes a rotor that rotates in conjunction with a wheel, a support that is fixed to a vehicle body, and is disposed on the support so as to face the rotor, and each of the back metal faces each other. A pair of pads formed by adhering a lining to the surface, a detection piece, and a detection element.
Of these, the detection piece is a part of the support, a portion between the two pads in the axial direction of the rotor, and a base attached to an outer portion of the outer periphery of the rotor in the radial direction of the rotor. And a pair of detection arms whose tip portions protrude from the base portion toward the opposite side surfaces of the back metal of the pads.
Further, when the detection element is installed on a part of the detection piece, and the tip of the detection arm is pressed by the side surface of the back metal with wear of the lining, and the detection piece is deformed, Based on this deformation, the output of the electric signal is a non-destructive type that continuously changes according to the degree of deformation.
[0011]
[Action]
A pair of detection arms is pushed back metal pad is accompanied in the lining is worn and deformed. And the detection element installed in a part of detection piece changes the output of an electrical signal, without destroying. For this reason, by guiding this output to the controller, it is possible to detect the progress of the lining wear at a remote location and further to detect that the lining has been worn to the limit.
[0012]
In this manner, since the displacement of the pad is mechanically detected by the detection arm , not only can the wear of the lining be reliably grasped, but it is also less susceptible to temperature changes at the pad portion.
[0013]
【Example】
1 to 7 show a first embodiment of the present invention corresponding to claims 1, 2, and 3, and FIG. 1 is a side view of the conventional disc brake shown in FIG. 2 is a plan view of the brake end portion excluding the caliper, FIG. 3 is also a partial side view, FIG. 4 is a perspective view of the detection piece, FIG. 5 is a development view of the detection piece, and FIGS. FIG. The same parts as those of the conventional example are denoted by the same reference numerals and the description thereof will be omitted.
[0014]
In this embodiment, the base 16 of the detection piece 15 shown in FIG. 4 is fixed to the support 2 by screwing, and the two detection arms 17 and 17 projecting therefrom are attached to the back metal 6a of the two pads at a position away from the rotor 1. inserted between, that occasion bent tip portion 17a is opposed to the inner surface of the backing metal 6a, inserting the piezoelectric element 18 as the detecting element between the two detection arms 17, 17 to each other, these two detection arms 17, 17 It is comprised between. As the sensing element, a piezoelectric element 18 (for example, ceramic) having a large heat resistance that generates a voltage having a different magnitude depending on the strength of pressurization when the two sensing arms 17 and 17 are pressurized can be used. The detection piece 15 is formed by punching an elastic metal plate as shown in FIG. 5 and bending it at folding lines 19 and 19 to form a base 16, a pair of detection arms 17 and 17 , a pair of distal ends 17a and 17a , and a support. A part 22, a pair of restraining arms 23 , 23 , a connecting part 24, etc., which are regulating members for restraining excessive expansion of both the detection arms 17 , 17 are formed. The distance between the tip edges of the tip portions 17a , 17a of the detection arms 17 , 17 and the back metal 6a is set to the allowable lining thickness L. Also, the screw insertion holes 25 for screwing the support 2 to the base portion 16, to the support portion 22 is a guide hole 27 for leading a lead wire 26 from the piezoelectric element 18, which respectively bored.
[0015]
Detecting piece 15 constituting in this manner, screwed to the base 16 on the end portion upper face of the support 2, the both detection arms 17, 17 of a pair disposed on the rotor on both sides at a position outside the rotor pads 6,6 the back metal 6a, inserted between the side surfaces facing each other of 6a, the tip portions 17a of both detection arms 17 and 17, the 17a, respectively the both backing 6a, is opposed to the opposing surfaces of 6a. Of these two back metal plates 6a, 6a, when the part removed from the linings 6b, 6b is narrow and there is little room for opposing the two front end parts 17a , 17a , as shown in FIG. 28 is formed so that the tip 17a is opposed .
[0016]
When the detecting piece 15 In this way keep attached to the disc brake, when the thickness of the lining 6b of the pad 6 is worn becomes permissible limit thickness L, a front end portion 17a of the both detecting arms 17, 17, 17a but backing 6a, detection arm 17 of the two is pressed by the 6a, 17 intervals between the Ru narrow or. Then, the output of the piezoelectric element 18 sandwiched between the detection arms 17 and 17 is transmitted from the electrodes 18a and 18b (FIG. 6) to the conductor 26 and displayed on the indicator 21 in the driver's seat through the amplifier 20 . The appear and the can know the state of wear of the lining 6b. Then , when the wear reaches the allowable limit thickness L of the lining 6b, an alarm can be issued by a lamp, sound, or the like.
[0017]
If a carbon block strain gauge 18 'whose electric resistance is changed by pressurization instead of the piezoelectric element 18 and connected to the power source 30 as shown in FIG. 7, pressurization to the strain gauge 18' as the lining wear progresses. becomes strong, by the current entering the indicator 21 through the amplifier 20 increases, it is possible to know the wear progress of the lining.
[0018]
The both detection arms 17, 17, by suppressing arms 23 and 23, respectively, since it is restricted from moving in the rotor axis direction away from the piezoelectric element 18, only the lining 6b is acceptable limit thickness of one of the pads 6 When the length becomes L, the detection arm 17 on the other pad 6 side does not escape away from the rotor 1. Therefore, even when only one of the linings 6b reaches the wear limit, the piezoelectric element 18 can be pressurized to detect wear well.
[0019]
8 and 9 show a second embodiment of the present invention corresponding to claims 1, 2, and 4. FIG. 8 is a schematic plan view similar to FIG. 2, and FIG. 9 is a schematic wiring diagram. The first embodiment described above is, with respect to that using the strain gauge of the piezoelectric element or carbon block as sensing element, in the case of this embodiment, as detection element, using the strain gauge 31 to bending deformation .
[0020]
In FIG. 8, the configuration of the detection piece 15 and the mounting structure to the disc brake are the same as in the first embodiment. In the case of the present embodiment, between the two sensing arms 17, 17 do not piezoelectric element is sandwiched. Instead, the bending portion 29, 29 of the pair constituting the detection piece 15, respectively attached to strain gauge 31, 31 of the plate, these two strain gauges 31 and 31, the wiring and as shown in FIG. 9 ing. As described in the first embodiment part of the aforementioned lining 6b of the pad 6, 6, the 6b is worn, the two detection arms 17, although 17 interval between narrows, the both bending portion 29 is accompanied thereto 29 , bending deformation occurs. The degree of this bending deformation becomes stronger with the progress of wear of the lining 6b, and the degree can be known by the change in the current (voltage) passing through both the strain gauges 31 and 31 . Therefore, if as shown in indicator 21 having a change in the magnitude of the current or voltage in the driver's seat while energizing these two strain gauges 31, 31 from the outside, wear state of the lining 6b, and until this is allowable limits You can know it is worn out. In this case , a piezoelectric polymer film (PVDF or the like) can be used as the strain gauges 31 and 31 . In FIG. 9 , both strain gauges 31 and 31 are connected in series, but both strain gauges can be connected independently.
[0021]
In the first and second embodiments, when the lining 6b reaches the allowable limit thickness L, the detection arm 17 starts to deform the detection element so as to directly notify that the lining 6b is approaching a dangerous state. can do. Also, since many piezoelectric materials are also pyroelectric materials, it is possible to simultaneously measure the temperature and add it to the display mode.
[0022]
【The invention's effect】
(1) The wear detection device can be handled as a single body by combining a detection element such as a piezoelectric element or a strain gauge with a detection piece, and can simplify electrical wiring.
[0023]
(2) Since the wear detection device is attached to the support independently of the caliper and the pad, even if the pad is changed due to wear of the lining , the wear detection device remains on the support as it is and may be discarded as before. It is economical because there is nothing.
[0024]
(3) Since there is no portion that wears by sliding on the rotor in the wear detection device, it can be used for a long time.
[0025]
(4) Since the pad replacement is performed while the detection element is supported by the support , the work of changing the lead wire as in the conventional case can be omitted and the workability is improved.
[0026]
(5) The detection piece can be easily manufactured by punching and bending a metal plate, and the detection element can be easily attached between the detection arms or between the bent portions by an adhesive, mechanical fitting, molding or the like.
[0027]
(6) Since the sensing element is located at a position away from the pad, it is less affected by heat generated during braking.
[Brief description of the drawings]
FIG. 1 is a side view of a disc brake equipped with a first embodiment of a detection device.
FIG. 2 is a plan view of the brake end portion excluding the caliper when the first embodiment is attached.
FIG. 3 is a partial side view of the same.
FIG. 4 is a perspective view of a detection piece.
FIG. 5 is a development view of a detection piece.
FIG. 6 is a schematic wiring diagram of the first embodiment.
FIG. 7 is a schematic wiring diagram when a carbon block strain gauge is used.
FIG. 8 is a schematic plan view of a brake left end portion similar to that of FIG. 2 showing a configuration summary of the second embodiment.
FIG. 9 is a schematic wiring diagram of a second embodiment.
FIG. 10 is a side view of a conventional disc brake.
11 is a cross-sectional view taken along the line AA in FIG. 11 except for the support.
12 is a plan view excluding a part of the caliper at the left end portion of FIG. 10;
FIG. 13 is a cross-sectional view of a pad portion showing a conventional contact wear detector.
FIG. 14 is a longitudinal sectional view of a caliper portion showing a conventional non-contact wear detecting device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotor 2 Support 3 Caliper 4 Guide pin 5 Ear | edge part 6 Pad 6a Back metal 6b Lining 7 Cylinder 8 Piston 9 Claw 10 Inner end part 11 Loop-shaped lead wire 12 Resin piece 13 Lead wire 14 Sensor 15 Detection piece 16 Base 17 Detection arm 17a Tip part 18 Piezoelectric element 18 'Carbon block strain gauge 18a Electrode 18b Electrode 19 Folding line 20 Amplifier 21 Indicator 22 Support part 23 Holding arm 24 Connection part 25 Insertion hole 26 Conductive line 27 Conductive hole 28 Convex part 29 Bending part 30 Power supply 31 Strain gauge L Allowable thickness limit

Claims (4)

A pair of rotors that rotate in conjunction with wheels, a support that is fixed to the vehicle body, and a support that is disposed on the support so as to face the rotor, and that each has a lining adhered to the mutually opposing surfaces of the back metal The detection piece comprises a part of the support, a portion between the two pads with respect to the axial direction of the rotor, and the rotor with respect to the radial direction of the rotor. A base portion attached to an outer side portion of the outer peripheral edge of the pad, and a pair of detection arms whose tip portions protrude from the base portion toward opposite side surfaces of the back metal of the pads, , is installed in a portion of the detecting piece, the distal end of the sensing arm I accompanied Do wear of the lining is pressed by the side surface of the back metal, in the case where the detection piece is deformed, on the basis of the deformation Electricity Abrasion detecting apparatus nondestructive disc brake pads for continuously changing according to the degree of deformation of the output of No.. Some of the sensing element, the two detection arms constituting the sensing element is provided with a regulating member for regulating the leaving in the axial direction from the rotor, the tip of one of the detection arm of these two sensing arms The disc brake pad wear detection device according to claim 1, wherein when only the portion is pressed by the side surface of the back metal, the other detection arm is prevented from being displaced in a direction away from the rotor . The sensor element according to claim 1 or 2, wherein the sensing element is a piezoelectric element or a strain gauge whose electrical resistance changes with pressure, and the piezoelectric element or strain gauge is sandwiched between the sensing arms. Disc brake pad wear detection device. The disc brake pad wear detection device according to claim 1 or 2, wherein the detection element is a pair of strain gauges, and the strain gauges are attached to a bent portion of the detection piece.

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