Friction member and friction member sensor system using the same

Abstract

To provide a friction member capable of detecting wear of a friction material consecutively and accurately before it reaches the state that requires replacement of the friction member, and provide a friction member sensor system using the same.SOLUTION: A friction material 2 of a friction member 1 (A1) includes: a region (first region 2a) comprising a first fiction material composition; and a region (second region 2b) comprising a second friction material composition which is prepared by adding a conductive material into the first friction material composition or a friction material composition different from the first friction material composition, and having high electric conductivity. A friction member sensor system (10A) measures an electric current flowing through the second region 2b of the friction material 2 with a wear detecting unit 5, and detects a wear state of the friction material 2.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a friction member used in brake devices for automobiles, railways, industrial machinery, etc., and a friction member sensor system using the same. [Background technology]

[0002] 2. Description of the Related Art Conventionally, disc brake devices and drum brake devices have been used as brake devices for automobiles, railways, industrial machinery, and the like.

[0003] A disc brake device is a brake device that has brake pads, which are made of friction material attached to a support member (back plate), as friction members, and a disc rotor as a mating member.A pair of brake pads, which are provided on both sides of the disc rotor that rotates integrally with the wheel, etc., are pressed against the disc rotor, respectively, to brake the wheel, etc.

[0004] A drum brake device is a brake device that has a brake shoe with a friction material attached to a support member (shoe rim) as a friction member, and a brake drum as a mating member.A pair of brake shoes are provided inside the brake drum, which rotates integrally with the wheel, etc., and each presses against the brake drum to brake the wheel, etc.

[0005] Such friction members are sometimes fitted with friction member sensors that detect the wear state of the friction material, and audible and electrical friction member sensors are known. An audible friction member sensor is configured to detect wear of the friction material by making a sound when a metal fitting attached to the friction member comes into contact with a mating member and the mating member when the friction material wears and becomes thinner (for example, Patent Document 1). An electrical friction member sensor is configured to detect wear of the friction material by making an electric wire embedded in the friction material become exposed and come into contact with a disc rotor or the like and break when the friction material wears and becomes thinner. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-39511 Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional friction material sensors detect when the friction material has become thin enough to require replacement by detecting the sound generated when a metal part comes into contact with a mating part or by detecting a broken wire embedded in the friction material. As a result, wear could not be detected unless the friction material reached a certain thickness.

[0008] An object of the present invention is to provide a friction member and a friction member sensor system using the same that can continuously and accurately detect wear of a friction material before the friction member reaches a state where replacement is necessary. [Means for solving the problem]

[0009] In order to achieve the above object, the invention of claim 1 of the present application provides a friction member having a friction material that comes into contact with a conductive counter member, the friction material comprising a first region made of a first friction material composition and a second region made of the first friction material composition or a different friction material composition to which a conductive material has been added and that has performance equivalent to that of the first friction material composition, the second region having a higher electrical conductivity than the first region and whose resistance value changes as the first region wears, and at least one surface of the second region is exposed so as to be able to come into contact with the counter member.

[0010] The invention according to claim 2 of the present application is characterized in that in the friction member according to claim 1, the second region has a cross-sectional area that varies in the thickness direction of the friction material.

[0011] The invention according to claim 3 of the present application is characterized in that in the friction member according to claim 1, the second region has a varying amount of the conductive material added in the thickness direction of the friction material.

[0012] The invention of claim 4 of the present application is a friction member sensor system including a conductive counter member and a friction member in contact with the counter member, the friction material being arranged so as to be in contact with the counter member, the friction material comprising a first region made of a first friction material composition and a second region made of a second friction material composition which is the first friction material composition or another friction material composition to which a conductive material has been added and has performance equivalent to that of the first friction material composition, the second region having a higher electrical conductivity than the first region and a resistance value which changes as the first region wears, at least one surface of the second region is exposed so as to be able to come into contact with the counter member, and the system is equipped with a wear detection unit which brings one surface of the exposed second region into contact with the counter member and detects wear of the friction material from the value of a current flowing in the second region or a resistance value calculated from the current value, or a change in the current value or the resistance value.

[0013] The invention according to claim 5 of the present application is characterized in that in the friction member sensor system according to claim 4, the counter member is part of a measurement path for the value of the current flowing through the second region.

[0014] The invention of claim 6 of the present application is characterized in that, in the friction member sensor system of claim 5, it comprises at least two second areas, one surface of each of the second areas is in contact with the mating member, the at least two second areas are connected in series via the mating member, and wear of the friction material is detected by the wear detection unit from the value of a current flowing through one of the second areas, the mating member, and the other of the second areas, or a resistance value calculated from the current value, or a change in the current value or the resistance value.

[0015] The invention according to claim 7 of the present application is characterized in that in the friction member sensor system according to any one of claims 4 to 6, the cross-sectional area of ​​the second region changes in the thickness direction of the friction material.

[0016] The invention of claim 8 of the present application is characterized in that, in the friction member sensor system of any one of claims 4 to 6, the second region has a varying amount of conductive material added in the thickness direction of the friction material.

[0017] The invention of claim 9 of the present application is characterized in that, in the friction member sensor system of any of claims 4 to 8, a wear information signal relating to the wear state of the friction material is generated from the detection result of the wear of the friction material detected by the wear detection unit.

[0018] The invention of claim 10 of the present application is characterized in that, in the friction member sensor system of claim 9, the wear information signal includes information indicating the wear state of the friction material before it reaches a wear state that requires replacement of the friction member. [Effects of the Invention]

[0019] According to the present invention, the wear state of the friction material can be accurately detected before the friction material reaches a wear state that requires replacement, and the wear state of the friction material can be accurately detected even when the friction material is worn unevenly.

[0020] According to the present invention, the second region used to detect the wear state of the friction material is a region made of a first friction material composition constituting the friction material or a second friction material composition obtained by adding a conductive material to another friction material composition and having performance equivalent to that of the first friction material composition. Therefore, the performance of the second region as a friction material is equivalent to that of the first region, and the performance as a friction material can be maintained. [Brief explanation of the drawings]

[0021] [Figure 1]FIG. 1 is an explanatory view of a first embodiment of a friction member of the present invention. [Figure 2] FIG. 4 is an explanatory view of a second embodiment of the friction member of the present invention. [Figure 3] FIG. 4 is an explanatory view of a third embodiment of a friction member of the present invention. [Figure 4] FIG. 1 is an explanatory diagram of a friction member sensor system according to a first embodiment of the present invention. [Figure 5] FIG. 4 is an explanatory diagram of a second embodiment of a friction member sensor system of the present invention. [Figure 6] FIG. 10 is an explanatory diagram of a third embodiment of a friction member sensor system of the present invention. [Figure 7] FIG. 10 is an explanatory diagram of a fourth embodiment of a friction member sensor system of the present invention. [Figure 8] FIG. 10 is an explanatory diagram of a fifth embodiment of a friction member sensor system of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The friction member of the present invention and the friction member sensor system using the same are configured such that the friction material constituting the friction member has a high electrical conductivity region (second region) made of a first friction material composition constituting the friction material or a second friction material composition obtained by adding a conductive material to another friction material composition and having performance equivalent to that of the first friction material composition. When the friction material wears, the second region also wears, and the value of the current flowing through this second region changes, making it possible to detect the wear state of the friction material. The friction member of the present invention and the friction member sensor system using the same are described below.

[0023] First, the friction member of the present invention will be described.

[0024] (First embodiment of friction member) 1 is an explanatory diagram of a first embodiment of the friction member of the present invention. Similar to a typical friction member (brake pad), the friction member 1A of this embodiment has a back surface of a friction material 2 adhered to a support member 3 (back plate), and the front surface of the friction material 2 is pressed against a disc rotor or the like to brake a wheel or the like.

[0025] The friction material 2 is made of common raw materials, specifically, a friction material composition including a binder such as phenolic resin, a fiber base material such as aramid pulp, a lubricant such as graphite or molybdenum disulfide, an inorganic friction modifier such as zirconium oxide or zirconium silicate, an organic friction modifier such as cashew dust, and a filler such as barium sulfide.

[0026] The friction material 2 also includes a first region 2a made of a first friction material composition containing the above-mentioned raw materials, and a second region 2b made of a second friction material composition to which a conductive material has been added. In the friction member 1A shown in FIG. 1, the second region 2b is cylindrical, and the friction material 2 is disposed so that the thickness direction thereof corresponds to the height of the column. The second region 2b is exposed on the surface of the friction material 2 that is subject to wear. While FIG. 1 illustrates the second region 2b as being exposed on the back surface of the friction material 2, the back surface of this exposed second region 2b is the region where an electrode for measuring the current value of the second region 2b is disposed in the friction member sensor system described below. If an electrode can be formed in this second region, it is not necessary to remove a portion of the support member 3 to expose the second region 2b, as shown in FIG. 1.

[0027] The conductive material added to the second region 2b is preferably selected from raw materials that, when added to the friction material composition constituting the first region 2a, provide equivalent friction material performance, such as the linear expansion coefficient and friction coefficient, between the first region 2a and the second region 2b. Specifically, when using common raw materials, the second region 2b can be formed by adding natural flake graphite. Note that the friction material composition constituting the first region 2a and the friction material composition constituting the second region 2b do not necessarily need to be the same; it is sufficient to select an appropriate raw material that provides equivalent friction material performance for the first region 2a and the second region 2b.

[0028] The amount of conductive material added to the second region 2b may be set within a range in which a desired current flows through the second region 2b, the current value changes with wear of the friction material 2, and the original performance of the friction material can be maintained. To achieve the desired current value, the diameter, height, etc. of the second region 2b may be changed at the same time.

[0029] In the friction member 1A shown in Fig. 1, the height of the cylindrical second region 2b decreases as the friction material 2 wears. Therefore, in a friction member sensor system described later, desired electrodes are brought into contact with both ends of the second region 2b, or the arrangement of the second region 2b is changed in various ways, and wear of the friction material 2 can be detected from the current flowing through the second region 2b. Details will be described later.

[0030] (Second embodiment of friction member) Next, a second embodiment of the friction member of the present invention will be described. FIG. 2 is an explanatory diagram of the second embodiment of the friction member of the present invention. Compared to the friction member 1A described in the first embodiment above, friction members 1B and 1C of this embodiment differ in the shape of the second region 2b. That is, the shape of the second region 2b is a truncated cone, and the cross-sectional area of ​​the friction material 2 varies in the thickness direction. In the shape of the second region 2b of friction member 1B shown in FIG. 2(a), the area of ​​the second region 2b exposed on the surface of the friction material 2 that is pressed against a disc rotor or the like is smaller than the area of ​​the back surface. On the other hand, in the shape of the second region 2b of friction member 1C shown in FIG. 2(b), the area of ​​the second region 2b exposed on the surface of the friction material 2 that is pressed against a disc rotor or the like is larger than the area of ​​the back surface.

[0031] In the friction member 1B having the structure shown in FIG. 2(a), the change in the current flowing through the second region 2b increases as the friction material 2 wears, compared to the friction member 1A described above. That is, when comparing the change in current value that occurs when the friction material 2 wears from a thick state to a predetermined thickness with the change in current value that occurs when the friction material 2 wears from a thin state to a predetermined thickness, the latter change is larger. Therefore, when a friction member sensor system is configured using the friction member 1B, it becomes possible to detect wear of the friction material 2 from the amount of change in the current, in addition to, or instead of, detecting the absolute value of the current. In particular, if a threshold value for the amount of change that requires preparation for replacement of the friction member 1B is set, reliable detection is possible even if an error occurs in the absolute value of the current when detecting the current, etc.

[0032] Similarly, in the friction member 1C having the structure shown in FIG. 2(b), the change in the current flowing through the second region 2b decreases as the friction material 2 wears, compared to the friction member 1A described above. That is, when comparing the change in current value that occurs when the friction material 2 wears from a thick state to a predetermined thickness with the change in current value that occurs when the friction material 2 wears from a thin state to a predetermined thickness, the latter change is smaller. Therefore, when a friction member sensor system is configured using the friction member 1C, it becomes possible to detect wear of the friction material 2 from the amount of change in the current value in addition to, or instead of, detecting the absolute value of the current value. In particular, this embodiment makes it possible to detect abnormal wear due to a system malfunction during the initial use of the vehicle.

[0033] The friction members 1B and 1C of the present embodiment are similar to the friction member 1A described in the first embodiment above, except for the shape of the second region 2b. Therefore, with the friction members 1B and 1C of the present embodiment, it is possible to detect wear of the friction material 2 from the current flowing through the second region 2b by bringing desired electrodes into contact with both ends of the second region 2b in a friction member sensor system described later, or by changing the arrangement of the second region 2b in various ways.

[0034] (Third embodiment of friction member) Next, a third embodiment of the friction member of the present invention will be described. FIG. 3 is an explanatory diagram of the third embodiment of the friction member of the present invention. Compared to the friction member 1A described in the first embodiment above, a friction member 1D of this embodiment differs in the amount of conductive material added in the thickness direction of the second region 2b. For example, the second region 2b of the friction member 1D shown in FIG. 3 is a cylindrical region divided into multiple regions (three regions in FIG. 3) in the thickness direction, and the amount of conductive material added decreases toward the front side of the friction material 2, which is pressed against a disc rotor or the like, toward the back side, or increases toward the front side.

[0035] The conductive material added to the second region 2b is preferably selected from raw materials and added in amounts that, when added to the friction material composition constituting the first region 2a, provide equivalent friction material performance, such as the linear expansion coefficient and friction coefficient, of the first region 2a and the second region 2b. Specifically, when using common raw materials, the second region 2b can be formed by adding natural flake graphite. Note that the friction material composition constituting the first region 2a and the friction material composition constituting the second region 2b do not necessarily need to be the same; raw materials may be selected as long as the first region 2a and the second region 2b have equivalent performance required of the friction material.

[0036] Furthermore, by varying the amount of conductive material added to the second region 2b in the thickness direction, the resistance value of the second region 2b in the thickness direction can be changed. In this case, too, the amount of conductive material added may be set within a range in which a desired current flows through the second region 2b, the current value changes with wear of the friction material 2, and the performance equivalent to that required of the original friction material can be maintained.

[0037] In the friction member 1D structured as shown in FIG. 3 , for example, if the amount of conductive material is reduced toward the surface of the friction material 2 that is pressed against a disc rotor or the like, and the conductive material is uniformly distributed within each of the three regions, as the friction material 2 wears, the change in current flowing through the second region 2b changes and becomes larger compared to the friction material 2 described in the first embodiment. That is, when comparing the change in current value that occurs when the friction material 2 wears from a thick state to a predetermined thickness with the change in current value that occurs when the friction material 2 wears from a thin state to a predetermined thickness, the latter change is larger. Therefore, wear of the friction material 2 can be detected by detecting the absolute value of the current value, which changes significantly when the friction material 2 reaches a predetermined thickness. In particular, if the current value is set to change significantly when the friction material 1D reaches a thickness that requires replacement, reliable detection is possible even if an error occurs in detecting the current value.

[0038] Similarly, if the amount of conductive material is increased toward the surface of the friction material 2 that is pressed against the disc rotor or the like, and the conductive material is uniformly distributed within each of the three regions, as the friction material 2 wears, the change in current flowing through the second region 2b changes and becomes smaller as the friction material 2 wears, compared to the friction material 2 described in the first embodiment. That is, when comparing the change in current value that occurs when the friction material 2 wears from a thick state to a predetermined thickness with the change in current value that occurs when the friction material 2 wears from a thin state to a predetermined thickness, the latter change is smaller. Therefore, in addition to or instead of detecting the absolute value of the current value, which becomes smaller when the friction material 2 reaches a predetermined thickness, it is possible to detect wear of the friction material 2 from the amount of change. Furthermore, the change in current is large when the friction material is thick, allowing for reliable detection of thickness changes, making it easier to detect abnormal wear due to system malfunctions during the early stages of vehicle use and to predict when the friction material should be replaced.

[0039] The friction member 1D of this embodiment is similar to the friction member 1A described in the first embodiment above, except for the change in the amount of conductive material added to the second region 2b. Therefore, with the friction member 1D of this embodiment, it is also possible to detect wear of the friction material 2 from the current flowing through the second region 2b by contacting desired electrodes with both ends of the second region 2b in a friction member sensor system described later, or by changing the arrangement of the second region 2b in various ways.

[0040] The friction member 1D of this embodiment can also be applied to the friction members 1B and 1C described in the second embodiment. In this case, too, desired electrodes are brought into contact with both ends of the second region 2b in a friction member sensor system described later, or the arrangement of the second region 2b is changed in various ways, and wear of the friction material 2 can be detected from the current flowing through the second region 2b.

[0041] The method of varying the amount of conductive material added is not limited to adding the amount of conductive material uniformly in each region, but may also involve gradually changing the amount of conductive material added, or a combination of these methods.

[0042] Next, the friction member sensor system of the present invention will be described.

[0043] (First embodiment of friction member sensor system) Fig. 4 is an explanatory diagram of a first embodiment of a friction member sensor system of the present invention. A friction member sensor system 10A of this embodiment is a friction member sensor system including the friction member 1A shown in Fig. 1, and shows an example in which the friction member sensor system of this embodiment is applied to a disc brake device.

[0044] As shown in FIG. 4, a pair of friction members 1 (A1) and 1 (A2) press against a disc rotor 4 (corresponding to a mating member) that rotates integrally with a wheel or the like, thereby braking the wheel or the like. Each friction member is composed of a friction material 2 that contacts the disc rotor 4 and a support member 3 (back plate) to which the friction material 2 is attached. The friction member 1 (A1) corresponds to the friction member 1A described in the first embodiment of the friction member above. The friction member 1 (A2) does not have the second region 2b of the friction material 2 of the friction member 1 (A1), and is composed entirely of only the friction material composition that constitutes the first region of the friction member 1A.

[0045] In a typical brake device, the friction material 2 presses against the disc rotor 4 to brake the wheels, etc., so repeated pressing causes the surface of the friction material 2 to wear, making it necessary to replace the friction members 1 (A1) and 1 (A2). Therefore, in the friction member sensor system 10A of this embodiment, in order to detect wear of the friction material 2, an electric current is passed through the second region 2b of the friction material 2, and the wear detection unit 5 detects wear of the friction material 2 from the current value.

[0046] To measure the current flowing through the second region 2b of the friction material 2, an electrode connected to the second region 2b is required. Therefore, as shown in FIG. 4, one electrode is formed on the surface of the friction material 2 of the friction member 1 (A1) facing the support member 3, consisting of a copper wire 6 that reaches the second region 2b and an electrode 7 for drawing out. Since the opposite surface of the friction material 2 is the surface where wear occurs, the disc rotor 4 is brought into contact with the exposed surface of the second region 2b. With this configuration, the disc rotor 4 functions not only as an electrode connected to the second region 2b, but also as part of the measurement path to the wear detection unit 5.

[0047] The disc rotor 4 may be made of a conductive material such as grey cast iron of FC150 to FC250.

[0048] The friction member sensor system 10A of this embodiment detects wear of the friction material 2 as follows: As shown in Fig. 4, the disc rotor 4 and the electrode 7 are used as a pair of electrodes, and the wear detection unit 5 measures the value of the current flowing through the second region 2b of the friction material 2 sandwiched between the pair of electrodes.

[0049] This current value can be accurately measured by pressing the friction member 1 (A1) against the disc rotor 4 with a preset constant pressure while the disc rotor 4 is stationary (the vehicle is not moving). Such control can be performed by a control unit (not shown) of a vehicle equipped with a brake device.

[0050] The current value can also be measured by pressing the friction member 1 (A1) against the disc rotor 4 with a preset constant pressure while the disc rotor 4 is moving (while the vehicle or the like is moving). Such control can also be performed by a control unit (not shown) of a vehicle or the like equipped with a brake device.

[0051] The wear detection unit 5 receives a current measured using the electrode 7 and the disc rotor 4 as electrodes, and generates and outputs a wear information signal S1 based on this current value. If the wear detection unit 5 stores a relationship between a predetermined current value or a resistance value calculated from this current value and the thickness of the friction material 2, the thickness of the friction material 2 can be calculated based on the input current value or resistance value. The output wear information signal S1 is not limited to a signal indicating the thickness of the friction material 2, as long as it is a signal indicating the wear state of the friction material 2. For example, the signal may indicate a thickness level, such as a state in which the friction material 2 is sufficiently thick and there is still time before friction members 1 (A1) and 1 (A2) need to be replaced; a state in which friction members 1 (A1) and 1 (A2) do not need to be replaced but preparation for replacement is desirable; or a state in which the friction material 2 is thin and friction members 1 (A1) and 1 (A2) need to be replaced; or a signal indicating the percentage (%) of thickness compared to a state without wear.

[0052] The wear information signal S1 may be output to a notifying unit (not shown) so that the driver or manager can recognize the wear state. For example, blue may be displayed when there is sufficient time before replacement of the friction members 1 (A1) and 1 (A2), yellow may be displayed when preparation for replacement is required, and red may be displayed when replacement is required. Alternatively, the signal for the notification may be a text display of the percentage of thickness compared to a state without wear, or a color display, a change in the display method such as flashing, or a sound such as a warning sound. In this way, the friction member sensor system of this embodiment is preferable because it allows the driver or manager to recognize the wear state before the friction members reach a state where replacement is necessary.

[0053] Incidentally, repeated braking by the brake device increases the temperature of the friction material 2. Therefore, it is preferable to correct the measured current value in accordance with the change in temperature of the friction material 2. Therefore, it is preferable to arrange a temperature sensor near the friction material 2 and detect the wear state from the current value corrected in accordance with the temperature change.

[0054] (Second embodiment of friction member sensor system) Next, a second embodiment of the friction member sensor system of the present invention will be described. Fig. 5 is an explanatory diagram of the second embodiment of the friction member sensor system of the present invention. Compared to the friction member sensor system 10A described in the first embodiment above, a friction member sensor system 10B of this embodiment differs in that it includes a friction member 1 (B1) having a plurality of second regions 2b.

[0055] In the friction member sensor system 10B of this embodiment, in order to detect wear of the friction material 2, a current is passed through the second region 2b (B1) and the second region 2b (B2) of the friction material 2, and the wear of the friction material 2 is detected from the current value by the wear detection unit 5. The second region 2b (B1) and the second region 2b (B2) of the friction material 2 shown in FIG. 5 each have the same structure as the second region 2b shown in FIG. 4.

[0056] To measure the current flowing through the second region 2b (B1) and the second region 2b (B2), electrodes are required to connect them. Therefore, as shown in FIG. 5, an electrode 7 (B1) is formed in the second region 2b (B1) on the surface of the friction material 2 of the friction member 1 (B1) facing the support member 3, and an electrode 7 (B2) is formed in the second region 2b (B2). The disc rotor 4 is also brought into contact with the surfaces of the second region 2b (B1) and the second region 2b (B2), which are the surfaces where wear occurs. With this configuration, the disc rotor 4 electrically connects the surfaces of the second region 2b (B1) and the second region 2b (B2) and functions as part of the measurement path for the current flowing through the second region 2b (B1) and the second region 2b (B2) to detect wear of the friction material 2.

[0057] The friction member sensor system 10B of this embodiment detects wear of the friction material 2 as follows: As shown in Fig. 5, an electrode 7 (B1) and an electrode 7 (B2) are used as a pair of electrodes, and the wear detection unit 5 measures the value of the current flowing through the second region 2b (B1) and the second region 2b (B2) of the friction material 2 connected in series between the pair of electrodes.

[0058] This current value can also be accurately measured by pressing the friction member 1 (B1) against the disc rotor 4 with a preset constant pressure while the disc rotor 4 is stationary (the vehicle is not moving). Such control can be performed by a control unit (not shown) of a vehicle equipped with a brake device.

[0059] The current value can also be measured by pressing the friction member 1 (B1) against the disc rotor 4 with a preset constant pressure while the disc rotor 4 is moving (while the vehicle or the like is moving). Such control can also be performed by a control unit (not shown) of a vehicle or the like equipped with a brake device.

[0060] The wear detection unit 5 receives the current measured using the electrodes 7 (B1) and 7 (B2) and generates and outputs a wear information signal S2 based on this current value. If the wear detection unit 5 stores the relationship between a predetermined current value or a resistance value calculated from this current value and the thickness of the friction material 2, the thickness of the friction material 2 can be calculated based on the input current value or resistance value. The output wear information signal S2 is not limited to a signal indicating the thickness of the friction material 2, as long as it is a signal indicating the wear state of the friction material 2. For example, the signal may indicate a thickness level, such as a state in which the friction material 2 is sufficiently thick and there is still time before friction members 1 (B1) and 1 (B2) need to be replaced; a state in which friction members 1 (B1) and 1 (B2) do not need to be replaced but preparation for replacement is desirable; or a state in which the friction material 2 is thin and friction members 1 (B1) and 1 (B2) need to be replaced; or a signal indicating the percentage (%) of thickness compared to a state without wear.

[0061] In particular, the friction member sensor system 10B of this embodiment is preferable because it can detect an average amount of wear when the amount of wear varies depending on the position on the friction material 2. Furthermore, the disc rotor 4 is a moving part, and it may be difficult to ensure a stable electrical connection, but according to this embodiment, the disc rotor 4 is not used as an electrode, and therefore a stable connection can be ensured.

[0062] The wear information signal S2 may be output to a notifying unit (not shown) to allow the driver or manager to recognize the wear state. For example, blue may be displayed when there is sufficient time before replacement of the friction members 1 (B1) and 1 (B2), yellow may be displayed when preparation for replacement is required, and red may be displayed when replacement is required. Alternatively, the signal for the notification may be a text display of the percentage of thickness compared to a state without wear, or a color display, a change in the display method such as flashing, or a sound such as a warning sound. In this way, the sensor system 10B of this embodiment is also preferable because it allows the driver or manager to recognize the wear state before the friction members reach a state where replacement is necessary.

[0063] In this embodiment as well, it is preferable to detect the wear state from the current value etc. corrected in accordance with the temperature change.

[0064] (Third embodiment of friction member sensor system) Next, a third embodiment of the friction member sensor system of the present invention will be described. Fig. 6 is an explanatory diagram of the third embodiment of the friction member sensor system of the present invention. Compared to the friction member sensor system 10A described in the first embodiment above, the friction member sensor system 10C of this embodiment differs in that it includes a friction member 1 (C1) corresponding to the friction member 1 (A1) and a friction member 1 (C2).

[0065] In the friction member sensor system 10C of this embodiment, in order to detect wear of a pair of friction materials 2, an electric current is passed through the second region 2b (C1) of the friction material 2 of the friction member 1 (C1) and the second region 2b (C2) of the friction material 2 of the friction member 1 (C2), and the wear detection unit 5 detects the wear of the friction material 2 of the friction member 1 (C1) and the wear of the friction material 2 of the friction member 1 (C2) from the current value.

[0066] To measure the current flowing through the second region 2b (C1) of the friction material 2 of the friction member 1 (C1) and the second region 2b (C2) of the friction material 2 of the friction member 1 (C2), electrodes are required to connect them. Therefore, as shown in Figure 6, an electrode 7 (C1) is formed in the second region 2b (C1) on the surface of the friction material 2 of the friction member 1 (C1) facing the support member 3, and an electrode 7 (C2) is formed in the second region 2b (C2) on the surface of the friction material 2 of the friction member 1 (C2) facing the support member 3. In addition, the disc rotor 4 is brought into contact with the surfaces of the second region 2b (C1) of the friction member 1 (C1) and the second region 2b (C2) of the friction member 1 (C2), which are surfaces where wear occurs. When configured in this manner, the disc rotor 4 electrically connects the surface of the second region 2b (C1) with the surface of the second region 2b (C2), and functions as part of the measurement path for the current flowing through the second region 2b (C1) and the second region 2b (C2) to detect wear of the friction material 2 of the friction member 1 (C1) and the friction material 2 of the friction member 1 (C2).

[0067] The friction member sensor system 10C of this embodiment detects wear of a pair of friction materials 2 as follows: The electrode 7 (C1) and the electrode 7 (C2) shown in Fig. 6 are used as a pair of electrodes, and the wear detection unit 5 measures the current flowing through the second region 2b (C1) of the friction material 2 of the friction member 1 (C1) and the second region 2b (C2) of the friction material 2 of the friction member 1 (C2), which are connected in series between the pair of electrodes.

[0068] This current value can also be accurately measured by pressing the friction members 1 (C1) and 1 (C2) against the disc rotor 4 with a preset constant pressure while the disc rotor 4 is stationary (the vehicle is not moving). Such control can be performed by a control unit (not shown) of a vehicle equipped with a brake device.

[0069] The current value can also be measured by pressing the friction members 1 (C1) and 1 (C2) against the disc rotor 4 with a preset constant pressure while the disc rotor 4 is moving (while the vehicle or the like is moving). Such control can also be performed by a control unit (not shown) of a vehicle or the like equipped with a brake device.

[0070] The wear detection unit 5 receives a current measured using the electrodes 7 (C1) and 7 (C2) and generates and outputs a wear information signal S3 based on this current value. If the wear detection unit 5 stores a relationship between a predetermined current value or a resistance value calculated from this current value and the thickness of the friction material 2, the thickness of the friction material 2 can be calculated based on the input current value or resistance value. The output wear information signal S3 is not limited to a signal indicating the thickness of the friction material 2, as long as it is a signal indicating the wear state of the friction material 2. For example, the signal may indicate a thickness level, such as a state in which the friction material 2 is sufficiently thick and there is still time before friction members 1 (C1) and 1 (C2) need to be replaced; a state in which friction members 1 (C1) and 1 (C2) do not need to be replaced but preparation for replacement is desirable; or a state in which the friction material 2 is thin and friction members 1 (C1) and 1 (C2) need to be replaced; or a signal indicating the percentage (%) of thickness compared to a state without wear.

[0071] The friction member sensor system 10C of this embodiment is particularly preferable because it can detect the average amount of wear on the inner and outer sides of the pair of friction materials 2. Furthermore, the disc rotor 4 is a moving part, and it may be difficult to ensure a stable electrical connection, but according to this embodiment, the disc rotor 4 is not used as an electrode, and therefore a stable connection can be ensured.

[0072] The wear information signal S3 may be output to a notifying unit (not shown) to allow the driver or manager to recognize the wear state. For example, blue may be displayed when there is sufficient time before replacement of the friction members 1 (C1) and 1 (C2), yellow may be displayed when preparation for replacement is required, and red may be displayed when replacement is required. Alternatively, the signal for the notification may be a text display of the percentage of thickness compared to a state without wear, or a color display, a change in display method such as flashing, or a sound such as a warning sound. In this way, the sensor system 10C of this embodiment is also preferable because it allows the driver or manager to recognize the wear state before the friction members reach a state where replacement is necessary.

[0073] In this embodiment as well, it is preferable to detect the wear state from the current value etc. corrected in accordance with the temperature change.

[0074] (Fourth embodiment of friction member sensor system) Next, a fourth embodiment of the friction member sensor system of the present invention will be described. Fig. 7 is an explanatory diagram of the fourth embodiment of the friction member sensor system of the present invention. Compared to the friction member sensor system 10C described in the third embodiment above, a friction member sensor system 10D of this embodiment differs in that it includes a friction member 1 (D2) having a second region 2b (D2) with a different arrangement.

[0075] In the friction member sensor system 10D of this embodiment, in order to detect wear of a pair of friction materials 2, an electric current is passed through the second region 2b (D1) of the friction material 2 of the friction member 1 (D1) and the second region 2b (D2) of the friction material 2 of the friction member 1 (D2), and the wear detection unit 5 detects the wear of the friction material 2 of the friction member 1 (D1) and the wear of the friction material 2 of the friction member 1 (D2) from the current value.

[0076] To measure the current flowing through the second region 2b (D1) of the friction material 2 of the friction member 1 (D1) and the second region 2b (D2) of the friction material 2 of the friction member 1 (D2), electrodes are required to connect them. Therefore, as shown in Figure 7, an electrode 7 (D1) is formed in the second region 2b (D1) on the surface of the friction material 2 of the friction member 1 (D1) that faces the support member 3, and an electrode 7 (D2) is formed in the second region 2b (D2) on the surface of the friction material 2 of the friction member 1 (D2) that faces the support member 3. In addition, the disc rotor 4 is brought into contact with the surfaces of the second region 2b (D1) of the friction member 1 (D1) and the second region 2b (D2) of the friction member 1 (D2), which are surfaces where wear occurs. When configured in this manner, the disc rotor 4 electrically connects the surface of the second region 2b (D1) with the surface of the second region 2b (D2), and functions as part of the measurement path for the current flowing through the second region 2b (D1) and the second region 2b (D2) to detect wear of the friction material 2 of the friction member 1 (D1) and wear of the friction material 2 of the friction member 1 (D2).

[0077] In this embodiment, the second region 2b (D1) of the friction material 2 of the friction member 1 (D1) and the second region 2b (D2) of the friction material 2 of the friction member 1 (D2) are located at relatively far apart positions, but this does not pose any problem because they are connected via the conductive disc rotor 4.

[0078] The friction member sensor system 10D of this embodiment detects wear of a pair of friction materials 2 as follows: The electrode 7 (D1) and the electrode 7 (D2) shown in Fig. 7 are used as a pair of electrodes, and the wear detection unit 5 measures the current flowing through the second region 2b (D1) of the friction material 2 of the friction member 1 (D1) and the second region 2b (D2) of the friction material 2 of the friction member 1 (D2), which are connected in series between the pair of electrodes.

[0079] This current value can also be accurately measured by pressing the friction members 1 (D1) and 1 (D2) against the disc rotor 4 with a preset constant pressure while the disc rotor 4 is stationary (the vehicle is not moving). Such control can be performed by a control unit (not shown) of a vehicle equipped with a brake device.

[0080] The current value can also be measured by pressing the friction members 1 (D1) and 1 (D2) against the disc rotor 4 with a preset constant pressure while the disc rotor 4 is moving (while the vehicle or the like is moving). Such control can also be performed by a control unit (not shown) of a vehicle or the like equipped with a brake device.

[0081] The wear detection unit 5 receives a current measured using the electrodes 7 (D1) and 7 (D2) and generates and outputs a wear information signal S4 based on the current value. If the wear detection unit 5 stores a relationship between a predetermined current value or a resistance value calculated from the current value and the thickness of the friction material 2, the thickness of the friction material 2 can be calculated based on the input current value or resistance value. The output wear information signal S4 is not limited to a signal indicating the thickness of the friction material 2, as long as it indicates the wear state of the friction material 2. For example, the signal may indicate a thickness level, such as a state in which the friction material 2 is sufficiently thick and there is still time before friction members 1 (D1) and 1 (D2) need to be replaced; a state in which friction members 1 (D1) and 1 (D2) do not need to be replaced but preparation for replacement is desirable; or a state in which the friction material 2 is thin and friction members 1 (D1) and 1 (D2) need to be replaced; or a signal indicating the percentage (%) of thickness compared to a state without wear.

[0082] In particular, in the friction member sensor system 10D of this embodiment, when the amount of wear differs depending on the position on the friction material 2 between the inner side and the outer side, by locating the second region at a position where wear progresses faster, it is possible to detect the average amount of wear even if the surface of the friction material 2 becomes tilted due to wear. Furthermore, at positions where wear progresses faster, the contact between the friction material 2 and the disc rotor 4 is strong, and the electrical resistance at the contact surface is low. This makes it possible to stably measure the value of the current flowing through the second region 2b (D1) and the second region 2b (D2).

[0083] The wear information signal S4 may be output to a notifying unit (not shown) to allow the driver or manager to recognize the wear state. For example, blue may be displayed when there is sufficient time before the friction members 1 (D1) and 1 (D2) need replacement, yellow may be displayed when preparation for replacement is required, and red may be displayed when replacement is required. Alternatively, the signal for the notification may be a text display of the percentage of thickness compared to a state without wear, or a color display, a change in the display method such as flashing, or a sound such as a warning sound. In this way, the sensor system 10D of this embodiment is also preferable because it allows the driver or manager to recognize the wear state before the friction members reach a state where replacement is necessary.

[0084] In this embodiment as well, it is preferable to detect the wear state from the current value etc. corrected in accordance with the temperature change.

[0085] (Fifth embodiment of friction member sensor system) Next, a fifth embodiment of the friction member sensor system of the present invention will be described. Fig. 8 is an explanatory diagram of the fifth embodiment of the friction member sensor system of the present invention. Compared to the friction member sensor system 10D described in the fourth embodiment above, a friction member sensor system 10E of this embodiment differs in that it includes friction members 1 (E1) and 1 (E2) each having a plurality of second regions 2b.

[0086] In the friction member sensor system 10E of this embodiment, in order to detect wear of a pair of friction materials 2, an electric current is passed through either or both of the second region 2b (E1) and the second region 2b (E2) of the friction material 2 of the friction member 1 (E1) and either or both of the second region 2b (E3) and the second region 2b (E4) of the friction material 2 of the friction member 1 (E2), and the wear detection unit 5 detects the wear of the friction material 2 of the friction member 1 (E1) and the wear of the friction material 2 of the friction member 1 (E2) from the current value.

[0087] To pass current through either or both of the second region 2b (E1) and the second region 2b (E2) of the friction material 2 of the friction member 1 (E1), and either or both of the second region 2b (E3) and the second region 2b (E4) of the friction material 2 of the friction member 1 (E2), electrodes are required to be connected to these regions. Therefore, as shown in Fig. 8, an electrode 7(E1) is connected to the second region 2b (E1) on the surface of the friction material 2 of the friction member 1 (E1) facing the support member 3, an electrode 7(E2) is connected to the second region 2b (E2), an electrode 7(E3) is connected to the second region 2b (E3) on the surface of the friction material 2 of the friction member 1 (E2) facing the support member 3, and an electrode 7(E4) is connected to the second region 2b (E4). By controlling the switches SW1 to SW4, at least two of the electrodes 7(E1) to 7(E4) can be selected.

[0088] The disc rotor 4 is brought into contact with the surfaces of the second region 2b (E1) of the friction member 1 (E1), the surface of the second region 2b (E2), the surface of the second region 2b (E3) of the friction member 1 (E2), and the surface of the second region 2b (E4) of the friction member 1 (E1), which are surfaces where wear occurs. With this configuration, the disc rotor 4 electrically connects the surfaces of the second regions 2b (E1) to 2b (E4) and functions as part of a measurement path for the current flowing through at least two selected second regions from the second regions 2b (E1) to 2b (E4) to detect wear of the friction material 2 of the friction member 1 (E1), wear of the friction material 2 of the friction member 1 (E2), or wear of the friction material 2 of the friction member 1 (E1) and wear of the friction material 2 of the friction member 1 (E2).

[0089] The friction member sensor system 10E of this embodiment detects wear of the friction material 2 as follows by controlling the on / off of the switches SW1 to SW4.

[0090] When the switches SW1 and SW2 are turned on and the switches SW3 and SW4 are turned off, the electrodes 7 (E1) and 7 (E2) become a pair of electrodes, and the wear of the friction material 2 of the friction member 1 (E1) can be detected by measuring the current flowing through the second region 2b (E1) and the second region 2b (E2) of the friction material 2 of the friction member 1 (E1) connected in series between the pair of electrodes by the wear detection unit 5. This is the same as the second embodiment described with reference to FIG. 5.

[0091] When switches SW1 and SW2 are turned off and switches SW3 and SW4 are turned on, electrodes 7 (E3) and 7 (E4) become a pair of electrodes, and the wear detection unit 5 measures the current flowing through the second region 2b (E3) and the second region 2b (E4) of the friction material 2 of the friction member 1 (E2) connected in series between the pair of electrodes, thereby making it possible to detect wear of the friction material 2 of the friction member 1 (E2).

[0092] When switches SW1 and SW4 are turned on and switches SW2 and SW3 are turned off, electrodes 7 (E1) and 7 (E3) become a pair of electrodes, and the wear of the friction material 2 of friction member 1 (E1) and the wear of the friction material 2 of friction member 1 (E2) can be detected by measuring the current flowing through the second region 2b (E1) of the friction material 2 of friction member 1 (E1) and the second region 2b (E3) of the friction material 2 of friction member 1 (E2), which are connected in series between the pair of electrodes, using wear detection unit 5. This is the same as the third embodiment described with reference to FIG. 6.

[0093] When switches SW1 and SW4 are turned off and switches SW2 and SW3 are turned on, electrodes 7 (E2) and 7 (E4) become a pair of electrodes, and the wear detection unit 5 measures the current flowing through the second region 2b (E2) of the friction material 2 of friction member 1 (E1) and the second region 2b (E4) of the friction material 2 of friction member 1 (E2), which are connected in series between the pair of electrodes, thereby making it possible to detect wear of the friction material 2 of friction member 1 (E1) and wear of the friction material 2 of friction member 1 (E2).

[0094] When switches SW1 and SW3 are turned on and switches SW2 and SW4 are turned off, electrodes 7 (E1) and 7 (E4) become a pair of electrodes, and the wear of the friction material 2 of friction member 1 (E1) and the wear of the friction material 2 of friction member 1 (E2) can be detected by measuring the current flowing through the second region 2b (E1) of the friction material 2 of friction member 1 (E1) and the second region 2b (E4) of the friction material 2 of friction member 1 (E2), which are connected in series between the pair of electrodes, using wear detection unit 5. This is the same as the third embodiment described in FIG. 7.

[0095] When switches SW1 and SW3 are turned off and switches SW2 and SW4 are turned on, electrodes 7 (E2) and 7 (E3) become a pair of electrodes, and the wear detection unit 5 measures the current flowing through the second region 2b (E2) of the friction material 2 of friction member 1 (E1) and the second region 2b (E3) of the friction material 2 of friction member 1 (E2), which are connected in series between the pair of electrodes, thereby making it possible to detect wear of the friction material 2 of friction member 1 (E1) and wear of the friction material 2 of friction member 1 (E2).

[0096] Furthermore, when all switches SW1 to SW4 are turned on, the wear detection unit 5 measures the current flowing through the second regions 2b (E1) and 2b (E2) of the friction material of the friction member 1 (E1) and the second regions 2b (E3) and 2b (E4) of the friction material 2 of the friction member 1 (E2), which are connected between the electrodes 7 (E1) and 7 (E2) and the electrodes 7 (E3) and 7 (E4), thereby making it possible to detect the wear of the friction material 2 of the friction member 1 (E1) and the wear of the friction material 2 of the friction member 1 (E2).

[0097] The above current values ​​can also be accurately measured by pressing the friction members 1 (E1) and 1 (E2) against the disc rotor 4 with a preset constant pressure while the disc rotor 4 is stationary (the vehicle is not moving). Such control can be performed by a control unit (not shown) of a vehicle equipped with a brake device. The on / off control of the switches SW1 to SW4 can also be performed by a control unit (not shown) of a vehicle equipped with a brake device.

[0098] This current value can also be accurately measured by pressing the friction members 1 (E1) and 1 (E2) against the disc rotor 4 with a preset constant pressure while the disc rotor 4 is moving (while the vehicle or the like is moving). This type of control can also be performed by a control unit (not shown) of a vehicle or the like equipped with a brake device. The on / off control of the switches SW1 to SW4 can also be performed by a control unit (not shown) of a vehicle or the like equipped with a brake device.

[0099] The wear detection unit 5 receives the current measured by controlling the on / off of the switches SW1 to SW4, and generates and outputs a wear information signal S5 based on the current value. If the wear detection unit 5 stores a relationship between a predetermined current value or a resistance value calculated from the current value and the thickness of the friction material 2, the thickness of the friction material 2 can be calculated based on the input current value or resistance value. The output wear information signal S5 is not limited to a signal indicating the thickness of the friction material 2, as long as it indicates the wear state of the friction material 2. For example, the signal may indicate a thickness level, such as a state in which the friction material 2 is sufficiently thick and there is still time before friction members 1 (E1) and 1 (E2) need to be replaced; a state in which friction members 1 (E1) and 1 (E2) do not need to be replaced but preparation for replacement is desirable; or a state in which the friction material 2 is thin and friction members 1 (E1) and 1 (E2) need to be replaced; or a signal indicating the percentage (%) of thickness compared to a state without wear.

[0100] In particular, in the friction member sensor system 10E of this embodiment, by controlling the on / off of the switches SW1 to SW4, wear at a desired position on the friction material 2 can be detected, and if the amount of friction varies depending on the position on the friction material 2, this variation can be detected. Also, by finding a combination that produces a high current value, it is possible to identify the position where wear is most advanced, and generate the friction information signal S5 based on that combination. Furthermore, turning all of the switches SW1 to SW4 on is preferable because it allows the average amount of wear at different positions on the inner and outer sides of a pair of friction materials 2 to be detected.

[0101] The friction member sensor system 10E of this embodiment is not limited to the above description, and may be configured to measure the current flowing through the second regions 2b(E1) to 2b(E4) of the friction material 2 of either the friction member 1(E1) or 1(E2). Also, it is not necessary to measure all of the currents.

[0102] The wear information signal S5 may be output to a notifying unit (not shown) to allow the driver or manager to recognize the wear state. For example, blue may be displayed when there is sufficient time before replacement of the friction members 1 (E1) and 1 (E2), yellow may be displayed when preparation for replacement is required, and red may be displayed when replacement is required. Alternatively, the signal for the notification may be a text display of the percentage of thickness compared to a state without wear, or a color display, a change in the display method such as flashing, or a sound such as a warning sound. In this way, the sensor system 10E of this embodiment is also preferable because it allows the driver or manager to recognize the wear state before the friction members reach a state where replacement is necessary.

[0103] In this embodiment as well, it is preferable to detect the wear state from the current value etc. corrected in accordance with the temperature change.

[0104] While the embodiment of the present invention has been described above as being applied to a disc brake device, the present invention is not limited to this. For example, the present invention can also be applied to a drum brake device, and modifications may be made as appropriate without departing from the spirit and scope of the invention.

[0105] The arrangement of the second regions can be changed as appropriate. Furthermore, when a plurality of second regions are arranged, the number is not limited to two or four, and the arrangement thereof can also be changed as appropriate.

[0106] Furthermore, the second region of the friction material 2 may be configured so that the cross-sectional area varies in the thickness direction of the friction member 2 as described in FIG. 2, or so that the amount of conductive material added varies in the thickness direction of the friction material 2 as described in FIG. 3. [Explanation of symbols]

[0107] 1: friction member, 2: friction material, 2a: first region, 2b: second region, 3: support member, 4: disc rotor, 5: wear detection unit, 6: copper wire, 7: electrode, 10: friction member sensor system

Claims

1. A friction member sensor system including a conductive counter member and a friction member having a pair of friction materials that are in contact with both side surfaces of the counter member and are arranged so as to be in contact with the counter member, The friction materials each include a first region made of a first friction material composition, and a second region made of only the first friction material composition or a different friction material composition to which a conductive material has been added and having performance equivalent to that of the first friction material composition, the second region having a higher electrical conductivity than the first region and a resistance value that changes as the first region wears, and the first region and the second region are in direct contact with each other, and at least one surface of the second region is exposed so as to be able to come into contact with the mating member. bringing one surface of the exposed second region into contact with the counter member; a friction member sensor system comprising a wear detection unit that detects wear of the friction material from a current value flowing through the second region of one of the pair of friction materials, the mating member, and the second region of the other of the pair of friction materials, or a resistance value calculated from the current value, or a change in the current value or the resistance value.

2. 2. The friction member sensor system according to claim 1, Each of the pair of friction materials includes at least two of the second regions, one surface of each of the second regions is brought into contact with the mating member; A friction member sensor system characterized in that at least two of the second regions are connected in series via the mating member, and the wear detection unit detects wear of the friction material from the current value flowing through one of the second regions, the mating member, and the other of the second regions, or the resistance value calculated from the current value, or from a change in the current value or the resistance value.

3. 3. The friction member sensor system according to claim 1, wherein: A friction member sensor system, wherein the second region has a cross-sectional area that changes in the thickness direction of the friction material.

4. 3. The friction member sensor system according to claim 1, wherein: A friction member sensor system, wherein the second region has a varying amount of conductive material added in a thickness direction of the friction material.

5. 3. The friction member sensor system according to claim 1, wherein: A friction member sensor system, characterized in that a wear information signal relating to the wear state of the friction material is generated based on the detection result of the wear of the friction material detected by the wear detection unit.

6. 6. The friction member sensor system according to claim 5, Friction member sensor system, characterized in that the wear information signal includes information indicating a wear state of the friction material before the friction member reaches a wear state requiring replacement.

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