FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION [See section 10, Rule 13] WEAR ESTIMATION DEVICE; MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED. 2 DESCRIPTION 5 Field [0001] The present disclosure relates to a wear estimation device for a brake component of a train. 10 Background [0002] A railway vehicle includes a brake system that performs braking by pressing a pad against a rotational body such as a wheel or a disc. The pad is worn by being used, and needs to be replaced when reaching a preset 15 remaining amount. Patent Literature 1 proposes an abrasion loss arithmetic device that obtains an abrasion amount of a pad on the basis of a brake pressure, a speed of a brake object, and a braking time. 20 Citation List Patent Literature [0003] Patent Literature 1: Japanese Patent Application Laid-open No. 2015-121251 25 Summary Technical Problem [0004] However, a wear amount of each brake device of the railway vehicle may change depending on a use state. Depending on the use state, a wear amount of only a certain 30 pad increases. In such a case, certain pads have been replaced with new pads even though a pad thickness has not reached a limit for performing brake control, and the old pads have been discarded. 3 Solution to Problem [0005] A wear estimation device according to the present disclosure includes: a state acquisition unit to acquire 5 information regarding wear amounts of a plurality of mechanical brake devices that are to brake a vehicle and regarding use states of the plurality of mechanical brake devices; a wear amount prediction unit to predict a wear amount change after a time point at which wear amounts of 10 the plurality of mechanical brake devices are measured or estimated, based on information regarding wear amounts of the plurality of mechanical brake devices and regarding use states of the plurality of mechanical brake devices at or before a time point at which wear amounts of the plurality 15 of mechanical brake devices are measured or estimated; and a replacement control unit to determine a replacement target of each of some of the plurality of mechanical brake devices based on a result predicted by the wear amount prediction unit by a time of a first inspection. 20 Advantageous Effects of Invention [0006] A wear estimation device of the present disclosure enables effective use of a brake component included in a mechanical brake device, by including: a 25 state acquisition unit that acquires information regarding wear amounts of a plurality of mechanical brake devices that brake a vehicle and regarding use states of the plurality of mechanical brake devices; a wear amount prediction unit that predicts a wear amount change after a 30 time point at which wear amounts of the plurality of mechanical brake devices are measured or estimated on the basis of information regarding wear amounts of the plurality of mechanical brake devices and regarding use 4 states of the plurality of mechanical brake devices at or before a time point at which wear amounts of the plurality of mechanical brake devices are measured or estimated; and a replacement control unit that determines a replacement 5 target of each of some of the plurality of mechanical brake devices on the basis of a result predicted by the wear amount prediction unit by a time of a first inspection. Brief Description of Drawings 10 [0007] FIG. 1 is a diagram illustrating a configuration example of a train according to a first embodiment. FIG. 2 is a diagram illustrating a configuration example of a brake control device according to the first embodiment. 15 FIG. 3 is a diagram illustrating a configuration example of a wear estimation device according to the first embodiment. FIG. 4 is a graph illustrating an example of a braking force according to the first embodiment. 20 FIG. 5 is a table illustrating an example of a wear amount of a mechanical brake device according to the first embodiment. FIG. 6 is a graph illustrating an example of a change in brake shoe thickness of each of the mechanical brake 25 device according to the first embodiment. FIG. 7 is a flowchart illustrating an operation of the wear estimation device according to the first embodiment. FIG. 8 is a table illustrating an example of a calculation result of the wear estimation device according 30 to the first embodiment. FIG. 9 is a graph illustrating an example of a change in brake shoe thickness of the mechanical brake device according to the first embodiment. 5 FIG. 10 is a table illustrating an example of a calculation result of an average value of wear amounts according to the first embodiment. FIG. 11 is a diagram illustrating a facility 5 configuration example of a wear estimation device according to the second embodiment. FIG. 12 is a diagram illustrating a configuration example of the wear estimation device according to the second embodiment. 10 FIG. 13 is a flowchart illustrating an example of an operation of the wear estimation device according to the second embodiment. FIG. 14 is a table illustrating a calculation result of the wear estimation device according to the second 15 embodiment. FIG. 15 is a table illustrating another example of a calculation result of the wear estimation device according to the second embodiment. FIG. 16 is a table illustrating another example of a 20 calculation result of the wear estimation device according to the second embodiment. FIG. 17 is a diagram illustrating a general configuration example of hardware that realizes a wear estimation device according to an embodiment. 25 Description of Embodiments [0008] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that, in the drawings, identical or 30 equivalent portions are denoted by the same reference numerals. [0009] First Embodiment. FIG. 1 is a diagram illustrating a configuration 6 example of a train 1 installed with a wear estimation device according to a first embodiment of the present disclosure. The train 1 includes vehicles 11 to 13. The vehicle 11 is provided with a cab 21, a brake control 5 device 100-1, a wear estimation device 140-1, mechanical brake devices 211 to 214, wheels 311 to 314, and trucks 411 and 412. The brake control device 100-1 and the mechanical brake devices 211 to 214 are connected. The wheels 311 and 312 are included in the truck 411, and the wheels 313 and 10 314 are included in the truck 412. The mechanical brake devices 211 to 214 are brake devices for braking of wheels. The mechanical brake device 211 brakes the wheel 311, the mechanical brake device 212 brakes the wheel 312, the mechanical brake device 213 brakes the wheel 313, and the 15 mechanical brake device 214 brakes the wheel 314. [0010] The vehicle 12 is provided with a cab 22, a brake control device 100-2, a wear estimation device 140-2, mechanical brake devices 221 to 224, wheels 321 to 324, and trucks 421 and 422. The brake control device 100-2 and the 20 mechanical brake devices 221 to 224 are connected. The wheels 321 and 322 are included in the truck 421, and the wheels 323 and 324 are included in the truck 422. The mechanical brake devices 221 to 224 are brake devices for braking of wheels. The mechanical brake device 221 brakes 25 the wheel 321, the mechanical brake device 222 brakes the wheel 322, the mechanical brake device 223 brakes the wheel 323, and the mechanical brake device 224 brakes the wheel 324. [0011] The vehicle 13 is provided with a brake control 30 device 100-3, a wear estimation device 140-3, mechanical brake devices 231 to 234, wheels 331 to 334, and trucks 431 and 432. The brake control device 100-3 and the mechanical brake devices 231 to 234 are connected. The wheels 331 and 7 332 are included in the truck 431, and the wheels 333 and 334 are included in the truck 432. The mechanical brake devices 231 to 234 are brake devices for braking of wheels. The mechanical brake device 231 brakes the wheel 331, the 5 mechanical brake device 232 brakes the wheel 332, the mechanical brake device 233 brakes the wheel 333, and the mechanical brake device 234 brakes the wheel 334. [0012] When the brake control devices 100-1 to 100-3 are not distinguished, they are each referred to as a brake 10 control device 100. The brake control devices 100 are connected to the cabs 21 and 22. [0013] When the wear estimation devices 140-1 to 140-3 are not distinguished, they are each referred to as a wear estimation device 140. The wear estimation devices 140 are 15 connected to the cabs 21 and 22. Further, the wear estimation devices 140 may be connected to the brake control devices 100. [0014] The cabs 21 and 22 output brake commands for braking the train. The brake command includes information 20 regarding deceleration, and is outputted from a master controller, an automatic train control (ATC), or an automatic train operation (ATO) provided in each of the cabs 21 and 22. [0015] The mechanical brake devices 211 to 214, 221 to 25 224, and 231 to 234 mechanically brake the wheels, and are, for example, a tread brake, a disc brake, or the like. The mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 obtain a braking force by pressing brake components such as brake shoes and brake pads against the wheels. 30 [0016] The brake control device 100 outputs a command value indicating a mechanical braking force, which is a braking force generated by an operation of the mechanical brake, to the mechanical brake devices 211 to 214, 221 to 8 224, and 231 to 234. [0017] FIG. 2 is a diagram illustrating a configuration example of the brake control device according to the first embodiment of the present disclosure. The brake control 5 device 100 includes a command acquisition unit 110, a variable load detection unit 120, a necessary braking force calculation unit 130, and a mechanical braking force setting unit 150. [0018] The command acquisition unit 110 acquires a brake 10 command outputted from the cab, and transmits the brake command to the necessary braking force calculation unit 130. [0019] The variable load detection unit 120 detects loads on the vehicles 11 to 13 constituting the train 1 or 15 the trucks 411, 412, 421, 422, 431, and 432 included in the vehicles 11 to 13, and transmits a result to the necessary braking force calculation unit 130. [0020] The necessary braking force calculation unit 130 calculates a necessary braking force, which is a braking 20 force necessary for obtaining deceleration included in the brake command. The necessary braking force calculation unit 130 may calculate the necessary braking force for each vehicle or may calculate the necessary braking force for each truck. The necessary braking force calculation unit 25 130 calculates the necessary braking force for each vehicle or each truck on the basis of the brake command and the loads on the vehicles 11 to 13 or the trucks 411, 412, 421, 422, 431, and 432 included in the vehicles 11 to 13, and transmits a result to the mechanical braking force setting 30 unit 150. [0021] The mechanical braking force setting unit 150 outputs the necessary braking force to each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 9 234 on the basis of the necessary braking force outputted from the necessary braking force calculation unit 130. [0022] FIG. 3 is a diagram illustrating a configuration example of the wear estimation device 140. The wear 5 estimation device 140 includes a state acquisition unit 141, a wear amount prediction unit 142, and a replacement control unit 143. When wear amounts of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 are measured or estimated, the state acquisition unit 141 10 acquires information regarding the wear amount of each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234. The information regarding the wear amount of each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 may be a wear amount measured at a time 15 of an inspection or may be a wear amount estimated from past use states of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234. Further, the state acquisition unit 141 acquires a use state of each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234. 20 [0023] Here, "past" and "future" in the present disclosure will be explained. In the present disclosure, the "past" indicates a time point at which wear amounts of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 are measured or estimated, and a time point 25 before wear amounts of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 are measured or estimated. The "future" indicates a time point after wear amounts of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 are measured or estimated. A wear amount 30 acquisition unit 141 or the wear amount prediction unit 142 acquires information regarding the past use state. [0024] A use state of the mechanical brake device will be described. The use state indicates information 10 including any of a brake pressure, a speed of a braking target, a braking time, a use period, the number of times of braking, a braking force, vehicle characteristics, and the like, and individual pieces of information may be 5 associated. The "brake pressure" is a pressure such as an AC pressure and a BC pressure in the past when each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 is operated. The "speed of a braking target" is a speed in the past when each of the mechanical brake devices 10 211 to 214, 221 to 224, and 231 to 234 is operated. The "braking time" is a time period in which each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 is operated once, a total value of operation time periods in the past, or the like. The "use period" is a 15 period during which each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 has been used in the past. The "number of times of braking" is the number of times each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 has been used in the past. The 20 "braking force" is a braking force in one operation, a total value of braking forces in the past, or the like. The "vehicle characteristics" are a motive power car (M car) on which a main motor is installed, a trailer (T car) on which no main motor is installed, or the like. 25 [0025] When the measured or estimated wear amounts of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 are inputted, the wear amount prediction unit 142 predicts a future use state of each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 from 30 past use states. Specifically, from a use state before or at a time point at which the wear amounts of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 are measured or estimated, a use state after a time point at 11 which the wear amounts of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 are measured or estimated is predicted. On the basis of the predicted future use state, a future wear amount change is predicted, 5 and a prediction result is outputted to the replacement control unit 143. The prediction result may be a prediction result for each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234, may be a prediction result for each truck, or may be a prediction result for 10 each vehicle. For example, the prediction result for each truck may be a result predicted by averaging wear amounts of the mechanical brake devices provided in each truck. Furthermore, the prediction result for each vehicle may be a result predicted by averaging wear amounts of the 15 mechanical brake devices provided in the same vehicle among the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234. [0026] The replacement control unit 143 determines necessity of replacement of each of the mechanical brake 20 devices 211 to 214, 221 to 224, and 231 to 234 on the basis of the prediction result outputted from the wear amount prediction unit 142. Details will be described later. [0027] FIG. 4 is a graph illustrating an example of braking force borne by each vehicle in the first 25 embodiment. FIG. 4 illustrates a braking force borne by each of the vehicles 11 to 13. The braking force of the vehicle 11 is F1, the braking force of the vehicle 12 is F2, and the braking force of the vehicle 13 is F3. Here, the braking force of each vehicle is a braking force set by 30 the mechanical braking force setting unit. [0028] FIG. 5 is a table illustrating an example of wear amounts of the mechanical brake devices 211, 221, and 231 in the first embodiment. Here, the table illustrates wear 12 amounts of brake shoes, which are brake components of the mechanical brake devices 211, 221, and 231, when each of the mechanical brake devices 211, 221, and 231 provided in the vehicles 11, 12 and 13, respectively, perform a braking 5 operation with a braking force (ratio) illustrated in FIG. 4. A use period (days) is a period after the brake shoes are attached to the mechanical brake devices 211, 221, and 231. A new brake shoe thickness (mm) is a thickness of the brake shoe when attached to the mechanical brake device. A 10 current brake shoe thickness (mm) is a thickness (mm) of a current brake shoe. A wear amount (mm) is a wear amount after the brake shoe is attached to one of the mechanical brake devices 211, 221, and 231. A replacement brake shoe thickness (mm) is a necessary thickness of the brake shoe 15 for operating as the mechanical brake device. In other words, the brake shoe needs to be replaced when the thickness becomes the replacement brake shoe thickness. A predicted replacement time (days) is a replacement time at which the brake shoe is predicted to reach the replacement 20 brake shoe thickness. The predicted replacement time (day) indicates a period elapsed since the start of use. [0029] FIG. 6 is a graph illustrating an example of a change in brake shoe thickness of each of the mechanical brake devices 211, 221, and 231 in the first embodiment. 25 The graph illustrates thicknesses of the brake shoes attached to the mechanical brake devices 211, 221, and 231 illustrated in FIG. 5 with respect to the use period. In a use period from 0 days to 30 days indicated by solid lines, actual results are represented. After a use period from 31 30 days indicated by broken lines, predictions are indicated. [0030] Now 30 days have elapsed after the brake shoe of the mechanical brake device 211 has been attached, and the current brake shoe thickness is 30 (mm). The wear amount 13 for the use period of 30 days is indicated to be 30 (mm) because the brake shoe thickness when attached is 60 (mm). The replacement time of the brake shoe is predicted to be 40 days after the start of use. In other words, the brake 5 shoe thickness is predicted to reach the replacement brake shoe thickness in 10 days. [0031] Now 30 days have elapsed after the brake shoe of the mechanical brake device 221 has been attached, and the current brake shoe thickness is 45 (mm). The wear amount 10 for the use period of 30 days is indicated to be 15 (mm) because the brake shoe thickness when attached is 60 (mm). The replacement time of the brake shoe is predicted to be 80 days after the start of use. In other words, the brake shoe thickness is predicted to reach the replacement brake 15 shoe thickness in 50 days. [0032] Now 30 days have elapsed after the brake shoe of the mechanical brake device 231 has been attached, and the current brake shoe thickness is 40 (mm). The wear amount for the use period of 30 days is indicated to be 20 (mm) 20 because the brake shoe thickness when attached is 60 (mm). The replacement time of the brake shoe is predicted to be 60 days after the start of use. In other words, the brake shoe thickness is predicted to reach the replacement brake shoe thickness in 30 days. 25 [0033] As can be seen from FIGS. 5 and 6, the brake shoes of the mechanical brake devices 211, 221, and 231 have equal use periods, but have different thicknesses. That is, the wear amounts are different. Due to the different wear amounts, the predicted replacement time is 30 also different. [0034] An inspection cycle of the train 1 is assumed to be 30 days. The mechanical brake device 211 does not need replacement because the predicted brake shoe thickness 14 after 30 days from the start of use is 30 (mm), which exceeds the replacement brake shoe thickness 20 (mm). However, because the predicted replacement time of the brake shoe of the mechanical brake device 211 is 40 days, 5 the replacement brake shoe thickness will already be reached after 60 days from the start of use. Therefore, the brake shoe of the mechanical brake device 211 needs to be replaced even if the replacement brake shoe thickness has not yet been reached. 10 [0035] The mechanical brake device 221 does not need replacement because the predicted brake shoe thickness after 30 days from the start of use is 45 (mm), which exceeds the replacement brake shoe thickness 20 (mm). In addition, the predicted replacement time of the brake shoe 15 of the mechanical brake device 221 is indicated to be 80 days. [0036] The mechanical brake device 231 does not need replacement because the brake shoe thickness after 30 days from the start of use is 40 (mm), which exceeds the 20 replacement brake shoe thickness 20 (mm). In addition, the predicted replacement time of the brake shoe of the mechanical brake device 231 is indicated to be 60 days. [0037] As described above, it is indicated that, when the mechanical brake devices 211, 221, and 231 perform the 25 braking operation with the braking force (ratio) illustrated in FIG. 4, the brake shoe of the mechanical brake device 211 needs replacement but the brake shoes of the mechanical brake devices 221 and 231 do not need replacement in the inspection after 30 days from the start 30 of use. [0038] However, the mechanical brake device 211 has the brake shoe thickness of 30 (mm) after 30 days from the start of use, and needs replacement although the brake shoe 15 thickness has a margin of 10 (mm). In the typical replacement, the brake shoe is replaced with a new brake shoe, and the old brake shoe is discarded. That is, the brake shoe installed in the mechanical brake device 211 is 5 discarded although the brake shoe thickness remains 10 (mm). [0039] Therefore, the brake wear estimation device of the present disclosure performs control to effectively use the brake shoe installed in the mechanical brake device. 10 Here, the inspection performed after 30 days from the start of use is referred to as a first inspection, and the inspection performed after 60 days from the start of use is referred to as a second inspection. The mechanical brake device 211 needs replacement at a time of the first 15 inspection because the replacement brake shoe thickness is reached before the second inspection. The second inspection is an inspection to be performed after the first inspection. Here, a cycle of the first inspection is set to be 30 days after the start of use and a cycle of the 20 second inspection is set to 60 days after the start of use; however, the number of days may be appropriately set. [0040] FIG. 7 is a flowchart illustrating an operation of the wear estimation device 140 according to the first embodiment. When wear amounts of the mechanical brake 25 devices 211 to 214, 221 to 224, and 231 to 234 are measured or estimated, the wear estimation device 140 acquires information indicating the wear amounts of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 in the state acquisition unit 141 (S11). Further, the state 30 acquisition unit 141 acquires a use state of each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234. Next, the wear amount prediction unit 142 predicts future use states of the mechanical brake devices 211 to 16 214, 221 to 224, and 231 to 234 from past use states. On the basis of the predicted future use states, a future wear amount change is predicted (S12). Next, on the basis of the future wear amount prediction result predicted by the 5 wear amount prediction unit 142, the replacement control unit 143 determines whether some of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 need replacement in the second inspection (S13). When the replacement control unit 143 determines that the mechanical 10 brake devices do not need replacement in the second inspection, the process ends (S13: N). When the replacement control unit 143 determines that some of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 need replacement in the second inspection, a 15 replacement target of each of some of the mechanical brake device is determined (S13: Y). The wear estimation device 140 performs the present operation for each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234. The operation described above is performed by the 20 first inspection or at a time of the first inspection. [0041] FIG. 8 is a table illustrating an example of replacement targets calculated by the wear estimation device 140 according to the first embodiment. FIG. 8 indicates that the wear estimation device 140 has 25 determined the mechanical brake device 221 as the replacement target of the mechanical brake device 211. Further, it is indicated that the mechanical brake device 211 is determined as the replacement target of the mechanical brake device 221. Specifically, it is indicated 30 that the wear estimation device 140 has determined that the brake shoe of the mechanical brake device 211 needs replacement in the second inspection in accordance with the operation illustrated in FIG. 7, and has determined the 17 brake shoe of the mechanical brake device 221 as the replacement target of the mechanical brake device 211. Further, in accordance with the operation illustrated in FIG. 7, the brake shoe of the mechanical brake device 221 5 itself is determined not to need replacement in the second inspection, but is to be replaced when the mechanical brake device 221 is determined as the replacement target by the wear estimation device 140. [0042] FIG. 8 indicates that the wear estimation device 10 140 has compared wear amounts of the mechanical brake devices 211, 221, and 231, and determined, as the replacement targets, the mechanical brake device 211 having the largest wear amount and the mechanical brake device 221 having the smallest wear amount. 15 [0043] FIG. 9 is a graph illustrating an example of a change in brake shoe thickness when each of the mechanical brake devices 211, 221, and 231 is replaced with the replacement target illustrated in FIG. 8. Until 30 days after the start of use, the mechanical brake device 211 20 includes the brake shoe 1, the mechanical brake device 221 includes the brake shoe 2, and the mechanical brake device 231 includes the brake shoe 3. In the inspection after 30 days from the start of use, the brake shoe is replaced with the replacement target indicated by the wear estimation 25 device 140. Specifically, the brake shoes of the mechanical brake device 211 and the mechanical brake device 221 are exchanged. The brake shoe 1 that has been installed in the mechanical brake device 211 is to be installed in the mechanical brake 221 in the inspection 30 after 30 days from the start of use. Further, the brake shoe 2 that has been installed in the mechanical brake device 221 is to be installed in the mechanical brake 211 in the inspection after 30 days from the start of use. In 18 FIG. 9, solid lines of the graph indicate a change in brake shoe thickness from 0 days to 30 days after the start of use, and broken lines of the graph indicate a change in brake shoe thickness from 31 days to 60 days after the 5 start of use. In other words, the broken line of the graph indicates a change in brake shoe thickness of each of the mechanical brake devices 211, 221, and 231 after the brake shoes are replaced in the inspection after 30 days from the start of use. 10 [0044] As can be seen from FIG. 9, by exchanging the brake shoes of the mechanical brake devices 211 and 221 in the inspection after 30 days from the start of use, the brake shoe 1 can be used until 60 days from the start of use. That is, a brake shoe that should have been discarded 15 before reaching the replacement brake shoe thickness in the conventional inspection, can be used until reaching the replacement brake shoe thickness. [0045] As described above, in the brake wear amount estimation device 140 of the present disclosure, because 20 the replacement target can be determined on the basis of the wear amount and the use state, the brake component can be effectively used. [0046] A criteria for the wear estimation device 140 to determine the replacement target can be appropriately set. 25 For example, a mechanical brake device having the largest wear amount and a mechanical brake device having the smallest wear amount are determined to be the replacement targets. In addition, an average of wear amounts of the mechanical brake devices may be calculated, and the 30 replacement target may be determined on the basis of a difference from the average value, or may be determined according to other criteria. [0047] FIG. 10 illustrates an example in which the 19 replacement targets are determined on the basis of a difference from an average value. An "wear amount average value" indicates an average value of wear amounts of mechanical brake devices A to D. A "difference from the 5 average value" indicates a difference between the wear amount average value and the wear amount. A positive difference from the average value indicates that the wear amount is smaller than the wear amount average value. In other words, it is indicated that the wear is small. A 10 negative difference from the average value indicates that the wear amount is larger than the wear amount average value. In other words, it is indicated that the wear is large. FIG. 10 indicates that the mechanical brake device C having the largest numeric value on the positive side as 15 a difference from the average value and the mechanical brake device D having the largest numeric value on the negative side as a difference from the average value are to be replaced. In addition, it is indicated that the mechanical brake device B having the second largest 20 numerical value on the positive side as a difference from the average value and the mechanical brake device A having the second largest numerical value on the negative side as a difference from the average value are to be replaced. [0048] The wear estimation device 140 may be provided in 25 each of the vehicles 11 to 13. It suffices that one or more of the wear estimation devices 140 are provided in the train 1. The wear estimation device 140 can determine a mechanical brake device in the same vehicle among the vehicles 11 to 13 as a replacement target. By determining 30 the mechanical brake device in the same vehicle among the vehicles 11 to 13 as the replacement target, a moving distance of an inspector can be reduced when the mechanical brake device is replaced in the inspection. For example, a 20 moving distance of the inspector can be reduced by determining an mechanical brake device to be replaced and a replacement target thereof out of the mechanical brake devices 211 to 214 in the train 11. 5 [0049] In addition, it is possible to determine a mechanical brake device having a short distance from the currently installed mechanical brake device, as a replacement target. In other words, another mechanical brake device, which is located at a position close to a 10 position of the currently installed mechanical brake device in the same vehicle or another vehicle among the vehicles 11 to 13, can be determined as a replacement target. By determining, as the replacement target, another mechanical brake device that is located at a position close to the 15 position of the currently installed mechanical brake device in the same vehicle or another vehicle among the vehicles 11 to 13, a moving distance of the inspector can be reduced at a time of replacement in the inspection. For example, a moving distance of the inspector can be reduced by 20 determining a replacement target and a mechanical brake device to be replaced with the replacement target out of the mechanical brake devices 213, 214, 231, and 232 in the trains 11 and 12. [0050] The information calculated by the wear estimation 25 device 140 illustrated in FIGS. 5 and 8 may be outputted to a monitor device (not illustrated) installed in the train 1 or may be outputted to a device installed on the ground. [0051] When determining the replacement target of any of the mechanical brake devices 211 to 214, 221 to 224, and 30 231 to 234, the wear estimation device 140 may determine "new" as the replacement target. For example, when the replacement target of the mechanical brake device E is determined, if the replacement brake shoe thickness is 21 reached before the second inspection even if replacement is performed with any of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234, the replacement target may be determined as "new". A new brake shoe is newly 5 installed in the mechanical brake device E. By determining "new" as the replacement target, it is possible to clarify a component that needs to be ordered and facilitate the management of components. [0052] A wear estimation device according to the present 10 disclosure enables effective use of a brake component included in a mechanical brake device, by including: a state acquisition unit that acquires information regarding wear amounts of a plurality of mechanical brake devices that brake a vehicle and regarding use states of the 15 plurality of mechanical brake devices; a wear amount prediction unit that predicts a wear amount change after a time point at which wear amounts of the plurality of mechanical brake devices are measured or estimated on the basis of information regarding wear amounts of the 20 plurality of mechanical brake devices and regarding use states of the plurality of mechanical brake devices at or before a time point at which wear amounts of the plurality of mechanical brake devices are measured or estimated; and a replacement control unit that determines a replacement 25 target of each of some of the plurality of mechanical brake devices on the basis of a result predicted by the wear amount prediction unit by a time of a first inspection. [0053] In the wear estimation device according to the present disclosure, the wear amount prediction unit 30 predicts future use states of the plurality of mechanical brake devices and predicts a future wear amount change, so that the brake components included in the plurality of mechanical brake devices can be effectively used. 22 [0054] In the wear estimation device according to the present disclosure, wear amounts of the plurality of mechanical brake devices acquired by the state acquisition unit are wear amounts estimated on the basis of use states 5 of the mechanical brake devices, so that it is possible to effectively use the brake components included in the plurality of mechanical brake devices. [0055] In the wear estimation device according to the present disclosure, when the replacement control unit 10 determines that some of the plurality of mechanical brake devices need replacement at a time of the second inspection to be performed after the first inspection on the basis of the prediction result of the wear amount prediction unit, the replacement control unit determines a replacement 15 target of each of some of the plurality of mechanical brake devices, so that the brake component included in the mechanical brake device can be effectively used. [0056] In the wear estimation device according to the present disclosure, when the replacement control unit 20 determines a replacement target of any one of the plurality of mechanical brake devices, the replacement control unit determines, as the replacement target, a second mechanical brake device located at a position close to a position of a first mechanical brake device, so that a moving distance 25 can be reduced when the mechanical brake device is replaced in the inspection. [0057] Second Embodiment. In the first embodiment, the wear estimation device is installed in a train. In a second embodiment, a wear 30 estimation device is installed in a ground device. FIG. 11 is a diagram illustrating an example of the wear estimation device according to the second embodiment. In FIG. 11, trains 2 and 3 and a ground device 5 are provided. 23 Although two trains are illustrated in FIG. 11, the number of the trains may be one or may be three or more. The ground device 5 includes a wear estimation device 240. In FIG. 11, an arrow indicates a traveling direction of the 5 train. [0058] FIG. 12 is a diagram illustrating a configuration example of the wear estimation device 240 according to the second embodiment. The wear estimation device 240 includes a state acquisition unit 241, a wear amount prediction unit 10 242, and a replacement control unit 243. [0059] The state acquisition unit 241 acquires information regarding a wear amount of each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 installed in a train traveling on a track. The 15 information regarding the wear amount may be a wear amount measured at a time of an inspection or may be a wear amount estimated from past use states of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234. Further, the state acquisition unit 241 acquires a use state of each 20 of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234. The state acquisition unit 241 acquires the information regarding the wear amount and the use state from the train by means such as wireless communication or wired communication. In addition, the information 25 regarding the wear amount and the use state may be acquired from a portable medium recorded in the portable medium at a time of an inspection. [0060] The wear amount prediction unit 242 predicts a future use state of each of the mechanical brake devices 30 211 to 214, 221 to 224, and 231 to 234 from the past use state. On the basis of the predicted future use state, a future wear amount change is predicted and a prediction result is outputted to the replacement control unit 243. 24 [0061] The replacement control unit 243 determines necessity of replacement of each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 on the basis of the prediction result outputted from the wear amount 5 prediction unit 242. [0062] FIG. 13 is a flowchart illustrating an operation of the wear estimation device 240 according to the second embodiment. When wear amounts of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 are measured 10 or estimated, the wear estimation device 240 acquires information regarding the wear amount of each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 by the state acquisition unit 241 (S21). Further, the state acquisition unit 241 acquires a use state of each of 15 the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234. Next, the wear amount prediction unit 242 predicts future use states of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 from the past use states. On the basis of the predicted future use states, a 20 future wear amount change is predicted (S22). Next, on the basis of the future wear amount prediction result predicted by the wear amount prediction unit 242, the replacement control unit 243 determines whether some of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 need 25 replacement in the second inspection (S23). When the replacement control unit 243 determines that the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 do not need replacement in the second inspection, the process ends (S23: N). When the replacement control unit 243 determines 30 that some of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234 need replacement in the second inspection, a replacement target of each of some of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 25 234 is determined (S23: Y). The wear estimation device 240 performs the present operation for each of the mechanical brake devices 211 to 214, 221 to 224, and 231 to 234. The operation described above is performed by the first 5 inspection or at a time of the first inspection. [0063] FIG. 14 is a table illustrating an example of replacement targets determined by the wear estimation device 240 according to the second embodiment. FIG. 14 indicates that the wear estimation device 240 has 10 determined a mechanical brake device B of the train 2 as the replacement target of a mechanical brake device A of the train 2. In addition, it is indicated that the mechanical brake device A of the train 2 has been determined as the replacement target of the mechanical 15 brake device B of the train 2. [0064] FIG. 15 is a diagram illustrating another example of replacement targets determined by the wear estimation device 240 according to the second embodiment. FIG. 15 indicates that the wear estimation device 240 has 20 determined a mechanical brake device B of the train 3 as the replacement target of the mechanical brake device A of the train 2. In addition, it is indicated that a mechanical brake device A of the train 3 has been determined as the replacement target of the mechanical 25 brake device B of the train 2. As described above, because the wear estimation device 240 acquires the states of the mechanical brake devices in the plurality of trains, it is not limited to determine replacement only within a single train but it is also possible to determine replacement 30 among trains. [0065] In the above description, there is only one ground device 5 including the wear estimation device 240 according to the present disclosure, but there may be a 26 plurality of ground devices 5. Furthermore, there may be a plurality of ground devices 5 and a management device that controls the plurality of ground devices 5. Here, the management device is, for example, an operation management 5 device, an inspection and repair base, or the like. The ground device 5 may be a server, a cloud, or the like. [0066] Because the wear estimation device 240 according to the present disclosure is provided in the ground device 5, it is possible to perform future operation planning, 10 next maintenance planning, ordering of replacement components, and the like in consideration of the current wear state in each vehicle. Therefore, it is possible to perform efficient maintenance management. [0067] In a wear estimation device according to the 15 present disclosure, by the replacement control unit determining a mechanical brake device installed in a first train and a mechanical brake device installed in a second train as the replacement targets when determining replacement targets of the plurality of mechanical brake 20 devices, brake components included in the plurality of mechanical brake devices can be effectively used. [0068] Third Embodiment. FIG. 16 is a table illustrating another example of replacement targets determined by a wear estimation device 25 340 according to a third embodiment. FIG. 16 indicates that the wear estimation device 340 has determined "new" as a replacement target of the mechanical brake device A of the train 2, and determined "the mechanical brake device A of the train 3" as a replacement target of the mechanical 30 brake device B of the train 2. This indicates that a new brake shoe is installed in the mechanical brake device A of the train 2, and the replacement target of the mechanical brake device B of the train 2 is to be the mechanical brake 27 device A of the train 3 that is a different train. As described above, when a replacement brake shoe thickness is reached before second inspection even if replacement is performed with any mechanical brake device, the replacement 5 target may be determined as "new". [0069] FIG. 17 is a diagram illustrating an example of a case where processing circuitry included in the wear estimation device 140 (240, 340) is configured by a processor and a memory. In a case where the processing 10 circuitry is configured by a processor 1000 and a memory 1001, each function of the processing circuitry of the wear estimation device 140 (240, 340) is implemented by software, firmware, or a combination of software and firmware. The software or the firmware is described as a 15 program and stored in the memory 1001. In the processing circuitry, the processor 1000 reads and executes the program stored in the memory 1001 to implement each function. That is, the processing circuitry includes the memory 1001 for storage of a program by which processing of 20 the wear estimation device 140 (240, 340) is consequently executed. Further, it can also be said that these programs cause a computer to execute a procedure and a method of the wear estimation device 140 (240, 340). [0070] Note that, in the present disclosure, the 25 individual embodiments can be freely combined, or an embodiment can be appropriately modified or omitted within the scope of the invention. Reference Signs List 30 [0071] 1, 2, 3 train 5 ground device 11, 12, 13 vehicle 21, 22 cab 28 100, 100-1, 100-2, 100-3 brake control device 110 command acquisition unit 120 variable load detection unit 130 necessary braking force calculation unit 5 140, 140-1, 140-2, 140-3, 240, 340 wear estimation device 150 mechanical braking force setting unit 141, 241 state acquisition unit 142, 242 wear amount prediction unit 143, 243, 343 replacement control unit 10 211, 212, 213, 214, 221, 222, 223, 224, 231, 232, 233, 234 mechanical brake device 311, 312, 313, 314, 321, 322, 323, 324, 331, 332, 333, 334 wheel 411, 412, 421, 422, 431, 432 truck 15 1000 processor 1001 memory. 29 We Claim : 1. A wear estimation device comprising: a state acquisition unit to acquire information regarding wear amounts of a plurality of mechanical brake 5 devices that are to brake a vehicle and regarding use states of the plurality of mechanical brake devices; a wear amount prediction unit to predict a wear amount change after a time point at which wear amounts of the plurality of mechanical brake devices are measured or 10 estimated, based on information regarding wear amounts of the plurality of mechanical brake devices and regarding use states of the plurality of mechanical brake devices at or before a time point at which wear amounts of the plurality of mechanical brake devices are measured or estimated; and 15 a replacement control unit to determine a replacement target of each of some of the plurality of mechanical brake devices based on a result predicted by the wear amount prediction unit by a time of a first inspection. 20 2. The wear estimation device according to claim 1, wherein the wear amount prediction unit predicts future use states of the plurality of mechanical brake devices, and predicts a future wear amount change. 25 3. The wear estimation device according to claim 1 or 2, wherein wear amounts of the plurality of mechanical brake devices acquired by the state acquisition unit are wear 30 amounts estimated based on use states of the mechanical brake devices. 4. The wear estimation device according to any one of 30 claims 1 to 3, wherein the replacement control unit determines a replacement target of each of some of the plurality of mechanical brake devices when the replacement control unit determines that 5 some of the plurality of mechanical brake devices need replacement at a time of a second inspection to be performed after the first inspection, based on a prediction result of the wear amount prediction unit. 10 5. The wear estimation device according to any one of claims 1 to 4, wherein the replacement control unit determines, as a replacement target, a second mechanical brake device located at a position close to a position of a first 15 mechanical brake device, when determining a replacement target of any one of the plurality of mechanical brake devices. 6. The wear estimation device according to any one of 20 claims 1 to 5, wherein the wear estimation device is installed in the vehicle. 7. The wear estimation device according to any one of 25 claims 1 to 5, wherein the wear estimation device is installed in a ground device. 8. The wear estimation device according to claim 7, 30 wherein the replacement control unit determines, as replacement targets, a mechanical brake device installed in a first train and a mechanical brake device installed in a 31 second train, when determining the replacement targets of some of the plurality of mechanical brake devices.