JP7486624B1 - Vehicle brake device - Google Patents

Abstract

[Problem] One of the objects of the present invention is to provide a technology that can effectively utilize the amount of strain of a brake device during braking. [Solution] A vehicle brake device according to one aspect of the present invention includes a drive unit that is included in a vehicle and generates a pressing force that presses a friction material against a friction-bearing material that rotates when the vehicle is traveling, a transmission unit that transmits the pressing force input from the drive unit to the friction material, a holding unit that holds the transmission unit on the body of the vehicle, a stress detection unit that is provided in the holding unit and detects stress that occurs in the holding unit when the friction material is pressed against the rotating friction-bearing material and a braking torque that brakes the vehicle is generated, and an estimation unit 102 that estimates at least one of the coefficient of friction between the friction material and the friction-bearing material and the vehicle skid based on the stress detection result. [Selected Figure] Figure 2

Description

The present invention relates to a vehicle brake device.

Patent document 1 discloses a braking torque detection device that uses a strain gauge to detect distortion caused by compressive or tensile forces that occur in the bracket of a disc brake device for a railway vehicle during braking, and obtains the braking torque from the previously stored relationship between the distortion amount and the brake torque and the distortion amount detection result.

Japanese Patent Application Laid-Open No. 10-267055

The technology in Patent Document 1 only uses the detected amount of distortion as feedback for the control process of the disc brake device of the railway vehicle, and Patent Document 1 does not consider other uses for the detected amount of distortion.

The inventors recognized that there is room for improvement in terms of effectively utilizing the amount of distortion of the braking device during braking.

In view of the above, the object of the present invention is to provide a technology that can effectively utilize the amount of distortion of a braking device during braking.

In order to solve the above problems, a brake device according to one embodiment of the present invention is a brake device for a vehicle, comprising: a drive unit that generates a pressing force for pressing a friction material against a friction-bearing material that rotates when the vehicle is traveling; a transmission unit that transmits the pressing force input from the drive unit to the friction material; a holding unit that holds the transmission unit on the body of the vehicle; a stress detection unit that is provided on the holding unit and detects stress generated in the holding unit when the friction material is pressed against the rotating friction-bearing material and a braking torque that brakes the vehicle is generated; and an estimation unit that estimates at least one of the coefficient of friction between the friction material and the friction-bearing material and the skid of the vehicle based on the detection result of the stress.

The brake device of one embodiment of the present invention is a brake device for a vehicle, comprising: a drive unit that generates a pressing force for pressing a friction material against a friction-bearing material that rotates when the vehicle is traveling; a transmission unit that transmits the pressing force input from the drive unit to the friction material; a holding unit that holds the transmission unit on the body of the vehicle; a stress detection unit that is provided on the holding unit and detects stress generated in the holding unit when the friction material is pressed against the rotating friction-bearing material and a braking torque that brakes the vehicle is generated; and an abnormality estimation unit that estimates whether an abnormality has occurred in the vehicle brake device based on the detection result of the stress detection unit and the pressing force of the friction material at the time of detection by the stress detection unit.

The present invention provides a technology that can effectively utilize the amount of distortion of the braking device during braking.

In addition, any combination of the above, or mutual substitution of the components or expressions of the present invention among methods, devices, programs, temporary or non-temporary storage media on which programs are recorded, systems, etc. are also valid aspects of the present invention.

1 is a view including a partial cross section of a brake device according to a first embodiment; FIG. 2 is a functional block diagram of a processing device in the brake device of the first embodiment. 3(a) to 3(c) show the relationship between the initial velocity V and the friction coefficient μ during braking for each pressing force. FIG. 4 is a functional block diagram of a processing device in a brake device according to a modified example of the first embodiment. FIG. 11 is a functional block diagram of a processing device in a brake device according to another modified example of the first embodiment. FIG. 11 is a functional block diagram of a processing device in a brake device according to another modified example of the first embodiment. FIG. 11 is a functional block diagram of a processing device in a brake device according to a second embodiment. FIG. 13 is a functional block diagram of a processing device in a brake device according to another modified example of the second embodiment; FIG. 13 is a functional block diagram of a processing device in a brake device according to a third embodiment. 13 is a flowchart showing a process of a processing device according to a third embodiment. 4 shows the detection results of the stress detection unit and the transition of the wheel axle speed when skidding occurs. FIG. 13 is a functional block diagram of a processing device in a brake device according to a fourth embodiment. 13 is a flowchart showing a process of a processing device according to a fourth embodiment. FIG. 13 is a view including a partial cross section of a brake device according to a fifth embodiment. FIG. 13 is an exploded plan view showing a brake device according to a fifth embodiment. FIG. 13 is a side view of the brake device according to the fifth embodiment. FIG. 13 is an exploded side view showing the brake device according to the fifth embodiment. FIG. 13 is a schematic plan view illustrating an actuator according to a fifth embodiment.

The present invention will be described below based on a preferred embodiment with reference to the drawings. The dimensions of the components in each drawing are enlarged or reduced as appropriate to facilitate understanding. In addition, some components that are not important for explaining the embodiment are omitted in each drawing.

In addition, separate components that have something in common are distinguished by adding "first," "second," etc. to the beginning of their names, and these are omitted when referring to them collectively. In addition, terms that include ordinal numbers such as "first" and "second" are used to describe various components, but these terms are used only for the purpose of distinguishing one component from other components, and do not limit the components.

The brake device of the present invention includes a drive unit that generates a pressing force to press a friction material against a friction material that rotates when the vehicle is traveling, a transmission unit that transmits the pressing force input from the drive unit to the friction material, a holding unit that holds the transmission unit on the vehicle body, and a stress detection unit that is provided on the holding unit and detects stress generated in the holding unit when the friction material is pressed against the rotating friction material and a braking torque that brakes the vehicle is generated. A brake device of one aspect of the present invention includes an estimation unit that estimates at least one of the friction coefficient between the friction material and the friction material and the vehicle skid based on the detection result of the stress. A brake device of another aspect of the present invention includes an abnormality estimation unit that estimates whether or not an abnormality has occurred in the vehicle brake device based on the detection result of the stress detection unit and the pressing force of the friction material at the time of detection by the stress detection unit.

This configuration makes it possible to effectively utilize the amount of distortion of the brake device during braking. Below, we will explain each embodiment that can effectively utilize the amount of distortion of the brake device during braking.

First embodiment The configuration of a vehicle brake device 1 according to a first embodiment of the present invention will be described with reference to the drawings. As an example, the brake device 1 is preferably used as a brake device for a railway vehicle running on a railway track. Fig. 1 is a view including a partial cross section of the brake device 1 according to the first embodiment.

First, the overall configuration of the brake device 1 will be described. The brake device 1 includes a stress detection unit 30, a casing 45, a brake mechanism 60, and a processing device 100. In this embodiment, the casing 45 exemplifies a base unit for mounting the brake mechanism 60 to the vehicle body 90. For convenience, the side facing the wheel 92 from the brake mechanism 60 in the radial direction of the wheel 92 will be referred to as the wheel side (left side in FIG. 1), and the side opposite the wheel side will be referred to as the anti-wheel side (right side in FIG. 1).

The brake mechanism 60 mainly comprises an actuator 40, a brake output unit 61, a rod unit 62, a brake lever 64, and a retaining unit 73. The brake output unit 61 includes a brake shoe 72 and a brake shoe retaining unit 71 that retains the brake shoe 72. The brake mechanism 60 is a tread brake that generates a braking force by pressing the brake shoe 72 against the tread of a wheel 92 of a railway vehicle. The brake shoe 72 of this embodiment is an example of a friction material, and the tread portion of the wheel 92 of this embodiment is an example of a frictioned material. The brake output unit 61, rod unit 62, and brake lever 64 of this embodiment are an example of a transmission unit that transmits the pressing force input from the actuator 40 (drive unit) to the brake shoe 72.

In the brake mechanism 60, the actuator 40 is actuated, causing the arm 65 of the brake lever 64 to swing about the fulcrum 64a. This drives the brake output section 61 via the spherical bearing 66 provided at the tip of the arm 65 and the rod section 62.

The casing 45 is attached to the vehicle body 90 and functions as a base that supports the actuator 40, the brake output unit 61, and the stress detection unit 30. The casing 45 functions as an outer shell that houses the rod unit 62, the brake lever 64, the stress detection unit 30, etc.

The actuator 40 will now be described. The actuator 40 mainly comprises a cylinder 43, a fluid brake unit 44, and a push rod 46. The actuator 40 advances and retreats the push rod 46 by supplying and discharging compressed air as a pressurized fluid to and from the fluid brake unit 44. The actuator 40 of this embodiment is an example of a drive unit that generates a pressing force that presses the brake shoe 72 against the wheel 92 that rotates when the vehicle is traveling.

The cylinder 43 is formed into a generally bottomed cylindrical shape by combining multiple components together. A casing 45 is attached to the opening of the cylinder 43. The cylinder 43 houses a fluid brake unit 44, a push rod 46, and the like. The fluid brake unit 44 functions as a regular brake mechanism used for braking when the railway vehicle is in operation. The fluid brake unit 44 mainly comprises a compression chamber 49, a piston 51, and a spring 52.

The compression chamber 49 is defined by the bottom 43a of the cylinder 43 and the piston 51. One end of the spring 52 abuts against a portion of the piston 51 opposite the compression chamber 49, and the other end abuts against a wall 43b opposite the bottom 43a of the cylinder 43. An opening of the cylinder 43 is provided in the center of the wall 43b. The piston 51 is biased by the spring 52 in the direction opposite to the brake actuation direction. The piston 51 is housed in the cylinder 43 so that it can move back and forth along the axial direction of the cylinder 43.

The push rod 46 is a generally rod-shaped member arranged to extend along the brake actuation direction. One end of the push rod 46 is fixed to the piston 51, and the other end 46b is connected to one end 65b of the arm portion 65 of the brake lever 64. The arm portion 65 is connected to the other end 46b of the push rod 46 so as to be able to swing freely around the one end 65b. The one end 65b of the arm portion 65 is the input portion 64b of the brake lever 64. The input portion 64b corresponds to the force point of the brake lever 64.

When compressed air is supplied to the compression chamber 49, the piston 51 moves in the brake activation direction, i.e., toward the opposite wheel side, and the push rod 46 protrudes toward the opposite wheel side. When the push rod 46 protrudes, the input part 64b of the arm part 65 connected to the push rod 46 also moves toward the opposite wheel side. When the input part 64b moves toward the opposite wheel side, the spherical bearing 66 provided on the opposite side of the input part 64b of the arm part 65 moves toward the wheel side, and the brake output part 61 presses the brake shoe 72 against the wheel 92, generating a braking force between them.

When the supply of compressed air to the compression chamber 49 decreases, the piston 51 moves toward the wheel due to the biasing force of the spring 52, and the push rod 46 moves back toward the wheel. When the push rod 46 moves back, the input part 64b moves toward the wheel, the spherical bearing 66 moves toward the opposite side of the wheel, the pressing force of the brake shoe 72 decreases, and the braking force decreases.

The holding portion 73 suspends the brake output portion 61 including the brake shoe 72 and holds it so that it can rotate freely along a predetermined trajectory. The holding portion 73 includes a suspension portion 74 that suspends the brake output portion 61, and an attachment portion 75 that attaches the suspension portion 74 to the vehicle body 90.

The hanging part 74 is a lever-shaped member having a fulcrum part 74b provided at the upper end side and a support part 74c provided at the lower end side. The fulcrum part 74b of the hanging part 74 is rotatably connected to the fulcrum part 75c of the mounting part 75. The support part 74c of the hanging part 74 is rotatably connected to the brake output part 61 and supports the brake output part 61. The hanging part 74 in this embodiment is an example of a link part.

The mounting portion 75 has a fulcrum portion 75c and a base end portion 75d. The mounting portion 75 in this embodiment is a lever-shaped member extending from the anti-wheel side to the wheel side. The fulcrum portion 75c is connected to the fulcrum portion 74b of the hanging portion 74 via a connection pin 74p. The fulcrum portion 75c is disposed on the wheel side of the mounting portion 75 and protrudes to the outside from the casing 45. The base end portion 75d is disposed on the anti-wheel side of the mounting portion 75 and is attached to the casing 45. The mounting portion 75 in this embodiment is indirectly connected to the vehicle body 90 via the casing 45, but may be directly connected to the vehicle body 90. The holding portion 73 is sometimes referred to as a brake hanger.

The stress detection unit 30 is provided on the holding portion 73 and detects the stress generated in the holding portion 73 when the brake shoe 72 is pressed against the rotating wheel 92 and a braking torque that brakes the vehicle is generated. In this embodiment, the stress detection unit 30 is provided on the hanging portion 74 and detects the stress in the longitudinal direction of the hanging portion 74 that is generated in the hanging portion 74 when a braking torque is generated. In this example, the stress detection unit 30 is a load cell that converts the input load into an electrical signal.

In the brake mechanism 60 shown in FIG. 1, for example, when a braking force is applied to a wheel 92 rotating counterclockwise, the brake shoe 72 is dragged and pulled by the rotating wheel 92, and a downward torque is applied to the brake shoe 72. At this time, a downward load (stress) is input to the holding part 73 via the brake shoe holding part 71. The stress detection part 30 detects the load input to the holding part 73 and supplies it to the processing device 100.

Here, let us assume a configuration in which the stress detection unit 30 is provided in the brake output unit 61, rod unit 62, or brake lever 64 (i.e., the transmission unit). In this configuration, the transmission unit is subjected to stress based on the torque in the rotational direction (hereinafter referred to as "rotational stress") as well as stress in a direction intersecting the rotational direction (hereinafter referred to as "cross-direction stress"). In other words, the cross-direction stress is superimposed as an error on the detection result of the stress detection unit 30, reducing the measurement accuracy. Cross-direction stress can be caused by a component force of the driving force of the actuator 40 or by the inclination of the contact surface between the brake shoe 72 and the wheel 92.

On the other hand, with the configuration of this embodiment, the retaining portion 73 efficiently transmits stress in the rotational direction and hardly transmits stress in a direction intersecting the rotational direction, making it possible to accurately detect the torque in the rotational direction of the wheel 92 applied to the brake shoe 72 during braking.

Figure 2 is a functional block diagram of the processing device 100 in the brake device 1 of the first embodiment. Each functional block shown in Figure 2 and the following figures can be realized in hardware terms by electronic elements and mechanical parts such as a computer CPU, and in software terms by a computer program, but here, a functional block realized by the cooperation of these is depicted. Therefore, it will be understood by those skilled in the art that these functional blocks can be realized in various ways by combining hardware and software. The processing device 100 includes an acquisition unit 101, an estimation unit 102, an output unit 103, and a memory unit 104.

The acquisition unit 101 includes a stress acquisition unit 111, a pressing force acquisition unit 112, and a speed information acquisition unit 113. The stress acquisition unit 111 acquires the detection result of the stress detection unit 30. The pressing force acquisition unit 112 acquires the pressing force input from the actuator 40. The pressing force acquisition unit 112 can acquire the pressing force based on, for example, the air pressure of the brake cylinder device. The speed information acquisition unit 113 acquires speed information including the speed of the railway vehicle (hereinafter referred to as the vehicle speed). The vehicle speed may be acquired based on, for example, position information of a GPS (not shown) provided on the railway vehicle, or based on the detection result of a vehicle speed sensor (not shown) provided on the railway vehicle. The acquisition unit 101 supplies the acquired information to the estimation unit 102 and the memory unit 104.

The estimation unit 102 of this embodiment estimates the coefficient of friction between the brake shoe 72 and the wheel 92 based on the detection result of the stress generated in the retaining portion 73. The estimation unit 102 of this embodiment includes an actual braking torque calculation unit 121, an assumed braking torque calculation unit 122, and a comparison unit 123. The method of estimating the coefficient of friction in the estimation unit 102 will be described in detail later.

The output unit 103 outputs the friction coefficient estimated by the estimation unit 102 to an external device (not shown). The external device is, for example, a terminal device provided in the driver's cab of the railcar or in a management center that manages the operation of the railcar, and by receiving the estimated friction coefficient, can display the estimated result of the friction coefficient on its display.

The storage unit 104 stores acquired information and intermediate processing information generated by various processes in chronological order. The storage unit 104 stores programs for executing various processes of the present invention. In this embodiment, the storage unit 104 stores corresponding information. The corresponding information will be described later.

The method of estimating the friction coefficient in the estimation unit 102 will be described. First, the actual braking torque calculation unit 121 calculates the actual braking torque, which is the braking torque actually generated in the wheel 92, based on the detection result obtained from the stress detection unit 30. A known method is used to calculate the actual braking torque based on the detection result of the stress detection unit 30. For example, the actual braking torque calculation unit 121 calculates the actual braking torque by performing rosette analysis on the detection result of the stress detection unit 30 and extracting only the torque component in the rotational direction of the wheel from the load input to the holding unit 73.

Next, the assumed braking torque calculation unit 122 calculates the assumed braking torque, which is the braking torque assumed to have occurred in the wheel 92, based on the correspondence information and the pressing force and speed information at the time of detection by the stress detection unit 30.

The correspondence information will now be described with reference to Figures 3(a) and 3(b). Figure 3(a) shows the relationship between the initial velocity V and the friction coefficient μ during braking at a pressing force of F1 [kN], and Figure 3(b) shows the relationship between the initial velocity V and the friction coefficient μ during braking at a pressing force of F2 [kN]. Figures 3(a) and 3(b) show data for brake mechanisms A to D having the same configuration as brake mechanism 60. The friction coefficient μ here is the average value of the friction coefficient from when the brake is activated until a predetermined time has elapsed. The correspondence information is created in advance by measuring the friction coefficient of the friction material of brake mechanisms A to D at each pressing force and initial velocity, for example, using a brake dynamo test. Therefore, correspondence information for various pressing forces and initial velocities is stored in advance in memory unit 104.

The assumed braking torque calculation unit 122 of this embodiment compares the correspondence information with the pressing force and vehicle speed at the time of detection by the stress detection unit 30, and extracts from the correspondence information a friction coefficient (assumed friction coefficient) at the pressing force and vehicle speed at the time of detection by the stress detection unit 30. Based on the extracted assumed friction coefficient and the pressing force at the time of detection, an assumed braking torque is calculated using the following formula (1).
(Estimated braking torque) = (Pressing force) x (Friction coefficient) Formula (1)

The comparison unit 123 estimates the coefficient of friction generated between the brake shoe 72 and the wheel 92 based on the comparison result between the actual braking torque and the assumed braking torque. For example, the comparison unit 123 increases or decreases the assumed friction coefficient based on the difference between the actual braking torque and the assumed braking torque, and sets the friction coefficient after the increase or decrease as the estimated result. For example, the comparison unit 123 increases the assumed friction coefficient by a larger amount the difference is. Without being limited thereto, the comparison unit 123 may estimate the friction coefficient based on the degree of deviation, such as the difference or ratio, between the actual braking torque and the assumed braking torque, for example.

Here, the limit deceleration βmax, which is the limit of the deceleration of the railway vehicle, is determined by the value of the adhesion coefficient μ, as shown in the following equation (2). When the deceleration exceeds the limit deceleration βmax, the vehicle skids. The adhesion coefficient μ is the static friction coefficient acting between the tread of the wheel 92 and the track.
βmax = g × μ Equation (2)

The adhesion coefficient μ is measured under various conditions using an actual vehicle, including conditions under which the adhesion coefficient deteriorates (such as a wet track), and the set deceleration β is determined based on the following formula (3) by adopting the lower limit value μmin of the actual adhesion coefficient data so that the deceleration does not exceed the limit deceleration βmax.
β = g × μmin Equation (3)

Based on this set deceleration β, the braking force required when braking in the brake device, and the pressing force and braking pressure required to obtain the required braking force are calculated.

On the other hand, while road conditions are constantly changing, the adhesion coefficient μ is always set to a constant value on the safe side (for example, near the lower limit μmin) in the calculations used for braking force and powering torque, which means there is a discrepancy with the actual adhesion coefficient. Therefore, since in reality there is room to increase the deceleration to prevent skidding, there is room for improvement in terms of using a more appropriate deceleration.

In this embodiment, the estimation unit 102 estimates the friction coefficient between the brake shoe 72 and the wheel 92 based on the stress detection result. Since it can be assumed that the friction force between the brake shoe 72 and the wheel 92 and the adhesion force between the wheel 92 and the track are approximately equal, the actual adhesion coefficient can be grasped by grasping the friction coefficient. As a result, the grasped actual adhesion coefficient can be utilized for the slip control on the powered side, so that the transportation efficiency can be improved. For example, when the actual adhesion coefficient is large, the brake can be applied at a larger deceleration, so that the stopping distance can be shortened. In addition, since a larger deceleration can be used, it is possible to operate at a higher speed, so that it is possible to shorten the operation time between stations or to the destination. When the actual adhesion coefficient is low, the control of the ATO (automatic train operation) or TASC (tracking stop) can be changed in advance, and efficient operation is possible. Furthermore, since the adhesion coefficient can be grasped, wheel flats and slip of the wheels 92 can be suppressed in advance.

In this embodiment, the estimation unit 102 includes an actual braking torque calculation unit 121 that calculates an actual braking torque based on the detection result of the stress detection unit 30, an assumed braking torque calculation unit 122 that calculates an assumed braking torque based on the correspondence information and the pressing force and speed information at the time of detection by the stress detection unit 30, and a comparison unit 123 that estimates a friction coefficient based on a comparison result between the actual braking torque and the assumed braking torque. According to this configuration, the friction coefficient between the brake shoe 72 and the wheel 92 can be more accurately grasped by using the comparison result between the actual braking torque and the assumed braking torque obtained using the correspondence information.

The following describes the modified examples.

The stress detection unit 30 in the embodiment is provided on the hanging part 74 and detects the stress generated on the hanging part 74 when a braking torque is generated, but is not limited to this. The stress detection unit 30 may be provided on the mounting part 75, for example. Since the stress input to the hanging part 74 is transmitted to the mounting part 75, the stress detection unit 30 can detect this transmitted stress to estimate the coefficient of friction generated between the brake shoe 72 and the wheel 92.

In the embodiment, the brake device 1 is used in a railway vehicle, but is not limited thereto and may be used in other vehicles, such as automobiles.

In the embodiment, the speed of the vehicle is used as the speed information, but this is not limiting. For example, the speed information may include the rotational speed of the wheels 92. Therefore, the speed information may include at least one of the vehicle speed and the rotational speed of the wheels. The rotational speed of the wheels may be obtained, for example, by attaching a rotational speed sensor to the axle of the wheels 92, based on the detection result from the rotational speed sensor.

In the embodiment, the transmission unit is configured to amplify the driving force generated by the actuator 40 using the brake lever 64 and transmit it to the brake shoe 72, but this is not limited to the above, and the transmission unit may be configured to transmit the driving force generated by the actuator 40 to the brake shoe 72 as is without amplifying it.

In the embodiment, the pressing force is generated by the air pressure of the brake cylinder device, but this is not limited to this. For example, the pressing force may be generated by using an electric motor. In this case, for example, the pressing force may be detected based on the current value to the electric motor and the detection result of a pressure sensor for detecting the pressing force.

In the embodiment, the correspondence information indicates a predetermined correspondence relationship between the pressing force, the vehicle speed, and the friction coefficient, but is not limited to this, and may indicate, for example, a predetermined correspondence relationship between the pressing force, the vehicle speed, and the braking torque. Therefore, the correspondence information may be indicated by a predetermined correspondence relationship between the pressing force when the brake shoe 72 is pressed against the wheel 92 under a predetermined condition, the speed information when the brake shoe 72 is pressed against the wheel 92 with the pressing force, and at least one of the friction coefficient and the braking torque when the brake shoe 72 is pressed against the wheel 92 with the pressing force.

In the embodiment, the estimation unit 102 estimates the friction coefficient based on the comparison result between the actual braking torque and the expected braking torque, but this is not limited thereto, and the friction coefficient may be estimated based on the detection result of the stress detection unit 30 and the corresponding information. With this configuration, the friction coefficient between the brake shoe 72 and the wheel 92 can be grasped more accurately. For example, a learning model for calculating the friction coefficient from the detection result of the stress detection unit 30 may be created in advance by executing machine learning based on the detection result of the stress detection unit 30 and the corresponding information, and the detection result of the stress detection unit 30, the pressing force, and the speed information may be input to the created learning model, and the friction coefficient may be estimated from the output result.

The estimation unit 102 may estimate the friction coefficient based on the detection result of the stress detection unit 30 and the pressing force. According to this configuration, the friction coefficient between the brake shoe 72 and the wheel 92 can be grasped more accurately. For example, as described above, a learning model is created in advance by executing machine learning based on the detection result of the stress detection unit 30, the pressing force, and the friction coefficient, and the detection result of the stress detection unit 30 and the pressing force are input and the friction coefficient is output. The friction coefficient may be estimated from the output result by inputting the detection result of the stress detection unit 30 and the pressing force into the created learning model. In addition, an arithmetic expression for calculating the friction coefficient from the detection result of the stress detection unit 30 and the pressing force may be created in advance, and the friction coefficient may be estimated using the arithmetic expression. Similarly, the estimation unit 102 may estimate the friction coefficient based on the detection result of the stress detection unit 30, the pressing force, and the speed information.

Figure 4 is a functional block diagram of the processing device 100 in the brake device 1 of the modified example of the first embodiment. The acquisition unit 101 in Figure 4 further includes an inclination angle acquisition unit 114 that acquires the inclination angle on the track on which the railway vehicle runs at the time of detection by the stress detection unit 30. The estimation unit of this modified example estimates the friction coefficient based on the detection result of the stress detection unit 30, the pressing force, and the inclination angle. Here, the friction coefficient between the brake shoe 72 and the wheel 92 varies depending on the inclination angle on the track on which the vehicle runs. This inclination angle is acquired from various sensors provided on the railway vehicle and the track on which it runs. For example, by executing machine learning based on the detection result of the stress detection unit 30, the pressing force, the inclination angle, and the friction coefficient, a learning model is created in advance in which the detection result of the stress detection unit 30, the pressing force, and the inclination angle are input and the friction coefficient is output. The detection result of the stress detection unit 30, the pressing force, and the inclination angle may be input to the created learning model, and the friction coefficient may be estimated from the output result. According to this configuration, it is possible to estimate the friction coefficient with greater accuracy by taking the inclination angle into account.

Figure 5 is a functional block diagram of the processing device 100 in the brake device 1 of another modified example of the first embodiment. The acquisition unit 101 in Figure 5 further includes an environmental information acquisition unit 115 that acquires environmental information including at least one of the weather, temperature, and humidity at the running position of the railway vehicle at the time of detection by the stress detection unit 30. The estimation unit 102 of this modified example estimates the friction coefficient based on the detection result of the stress detection unit 30, the pressing force, and the environmental information. Here, the friction coefficient between the brake shoe 72 and the wheel 92 varies depending on the weather, temperature, and humidity. For example, the temperature and humidity at the running position of the railway vehicle are acquired from various sensors installed on the railway vehicle and the track on which it runs, and the weather at the running position is acquired from a weather data server outside the vehicle. For example, Figure 3 (c) shows the relationship between the initial velocity V and the friction coefficient μ during braking at a pressing force of F1 [kN] when the weather is rainy and the contact interface between the brake shoe 72 and the wheel 92 is wet. The friction coefficient in rainy weather as shown in FIG. 3(c) may be stored in advance in the storage unit 104 as corresponding information, and the friction coefficient may be estimated based on the corresponding information regarding rainy weather. Similarly, correspondence information for each temperature and humidity may be stored in advance in the storage unit 104, and the friction coefficient may be estimated based on the corresponding information. A learning model may be created in advance by executing machine learning based on the detection result of the stress detection unit 30, the pressing force, environmental information, and the friction coefficient, and the detection result of the stress detection unit 30, the pressing force, and environmental information may be input to the created learning model, and the friction coefficient may be estimated from the output result. With this configuration, it is possible to estimate the friction coefficient more accurately by taking into account the environmental information.

Fig. 6 is a functional block diagram of a processing device 100 in a brake device 1 according to another modified example of the first embodiment. The processing device 100 in Fig. 6 includes an acquisition unit 101, an estimation unit 102, a storage unit 104, a deceleration determination unit 105, and a brake control unit 106. The deceleration determination unit estimates an actual adhesion coefficient μ1 based on the estimated friction coefficient, and determines a set deceleration β based on the estimated adhesion coefficient. For example, the deceleration determination unit 105 uses the friction coefficient estimated by the estimation unit 102 as the adhesion coefficient μ1 as it is, and determines a set deceleration β based on the following formula (4).
β = g × μ1 Equation (4)
The brake control unit 106 controls the brakes using the set deceleration β determined based on the formula (4). With this configuration, the set deceleration β can be appropriately determined, so that it is possible to shorten the stopping distance and the operation time. Note that the processing device 100 in FIG. 6 may include an output unit 103.

Second embodiment Hereinafter, a second embodiment of the present invention will be described. In the drawings and description of the second embodiment, the same or equivalent components and members as those of the first embodiment are denoted by the same reference numerals. Descriptions that overlap with the first embodiment will be omitted as appropriate, and the description will focus on the configurations that differ from the first embodiment.

Figure 7 is a functional block diagram of the processing device 100 in the brake device 1 of the second embodiment. The acquisition unit 101 of the second embodiment further includes a traveling position acquisition unit 116.

The running position acquisition unit 116 acquires the running position of the railway vehicle at the time of detection by the stress detection unit 30. For example, the running position acquisition unit 116 acquires the running position based on the detection results of a GPS installed on the railway vehicle or a sign indicating the distance in kilometers from the starting point of the railway.

The output unit 103 in the second embodiment associates the friction coefficient estimated by the estimation unit 102 with the running position at the time of detection by the stress detection unit 30 and outputs the result to an external device.

Here, the coefficient of friction between the brake shoe 72 and the wheel 92 varies depending on the traveling position of the railway vehicle. For example, the degree of scattering of foreign objects such as fallen leaves, seawater, and sand, the inclination angle and deterioration state of the track, etc. vary depending on the position. According to the second embodiment, it is possible to associate the friction coefficient with the traveling position at that time and store it in an external device, so that it is possible to display, for example, the friction coefficient for each position on a route map. As a result, since the friction coefficient when traveling at that position can be accurately grasped, for example, it is possible to predict the appropriate deceleration when traveling at that position next time, which contributes to more accurate planning of traveling plans. For example, it is possible to accurately improve the friction coefficient by spreading sand at that position as necessary.

A modified example of the second embodiment will be described. Refer again to FIG. 5. The output unit 103 of this modified example outputs to an external device the friction coefficient estimated by the estimation unit 102 and the environmental information at the time of detection by the stress detection unit 30 in association with each other. With this configuration, the friction coefficient and the environmental information at that time can be associated and stored in the external device, so that the friction coefficient for each environmental information can be accurately grasped. As a result, for example, it is possible to obtain the friction coefficient corresponding to the environmental information during driving from the external device, so that an appropriate deceleration can be set according to the environmental information, which contributes to more accurate planning of driving plans.

Another modified example of the second embodiment will be described. FIG. 8 is a functional block diagram of the processing device 100 in the brake device 1 of another modified example of the second embodiment. The acquisition unit 101 in FIG. 8 includes a running direction acquisition unit 117 that acquires the running direction of the railway vehicle. This running direction is acquired, for example, from the detection result of the GPS. The processing device 100 in FIG. 8 further includes an axle identification unit 107 that identifies the axle of the wheel whose friction coefficient has been estimated among the multiple axles provided on the vehicle. In this modified example, an identification number is assigned to each stress detection unit 30, and the axle of the wheel 92 to which the brake device 1 to which the stress detection unit 30 corresponding to each identification number is attached applies a braking force is stored in the memory unit 104. The stress acquisition unit 111 acquires the identification number together with the detection result of the stress. The axle identification unit 107 acquires the identification number via the stress acquisition unit 111, and identifies the axle of the wheel whose friction coefficient has been estimated by reading the axle corresponding to the identification number from the memory unit 104. The output unit of this modified example outputs to an external device the detection result of the stress detection unit 30, the friction coefficient estimated by the estimation unit 102, the wheel for which the friction coefficient was estimated, and the running direction at the time of detection by the stress detection unit 30 in association with each other. Here, the adhesion coefficient between the wheel and the track is different for each axle. For example, a wheel located behind the running direction runs on a track where dirt and water have been removed by the running wheels located ahead of the running direction, so it is assumed that the friction coefficient is less slippery and is greater than the friction coefficient of the wheel located ahead of the running direction. According to this configuration, the friction coefficient can be grasped more accurately for each wheel taking into account the position of the axle and the running direction, so that a more appropriate deceleration can be set for each wheel, which contributes to more accurate planning of the running plan.

Third embodiment Hereinafter, a third embodiment of the present invention will be described. In the drawings and description of the third embodiment, the same or equivalent components and members as those of the first embodiment are denoted by the same reference numerals. Descriptions that overlap with the first embodiment will be omitted as appropriate, and the description will focus on the configurations that differ from the first embodiment.

Figure 9 is a functional block diagram of the processing device 100 in the brake device 1 of the third embodiment. The acquisition unit 101 of the third embodiment includes a stress acquisition unit 111. The estimation unit 102 of the third embodiment includes a slide estimation unit 124. The slide estimation unit 124 compares the detection result of the stress detection unit 30 with a reference value, and estimates whether or not the railcar is sliding based on the comparison result. The output unit 103 of the third embodiment outputs a signal to an external device when the railcar is sliding.

Figure 10 is a flowchart showing process S100 of the processing device 100 of the third embodiment. Process S100 is executed at a predetermined time interval (e.g., several milliseconds).

In step S101, the stress acquisition unit 111 acquires the detection result of the stress detection unit 30. The stress acquisition unit 111 supplies the acquired detection result to the memory unit 104. After step S101, the process S100 proceeds to step S102.

In step S102, the memory unit 104 stores the stress detection results. As a result, the stress detection results are accumulated in chronological order in the memory unit 104. After step S102, the process S100 proceeds to step S103.

In step S103, the skid estimation unit 124 judges whether or not skid is occurring in the railway vehicle based on the transition of the stress detection results stored in the memory unit 104. A method of judging skid in the skid estimation unit 124 will be described with reference to FIG. 11. FIG. 11 shows the detection results of the stress detection unit 30 and the transition of the axle speed of the wheel 92 when skid occurs as a result of braking while the vehicle is moving.

When the brakes are applied at time t1 while the railway vehicle is running, the axle speed of the wheels 92 gradually decreases and the stress detected by the stress detection unit 30 increases. If skidding occurs at time t2, the axle speed (actual axle speed in FIG. 11) drops sharply below the healthy axle speed shown by the dotted line in FIG. 11 due to skidding. Here, healthy axle speed is the axle speed assumed when it is assumed that skidding does not occur. After that, the wheels 92 and the track re-adhere, and the healthy axle speed and the actual axle speed become equal.

On the other hand, when skidding occurs at time t2, the stress (actual stress in FIG. 11) also drops sharply from the healthy stress shown by the dashed line in FIG. 11 due to skidding. This is because skidding reduces the axle speed, which in turn reduces the stress. Here, healthy stress is the stress that is expected when it is assumed that skidding does not occur. After that, the wheel 92 and the track re-adhere, and the healthy stress and actual stress become equal.

The skid estimation unit 124 detects this sudden drop in stress and determines whether skid is occurring. For example, the skid estimation unit determines that skid is occurring when the amount of change in stress from the time point at which the stress was detected a predetermined time ago (the difference between the minimum value of stress and a reference value) is greater than the skid threshold value. The reference value here is, for example, the detection result of the stress detection unit 30 from the time point at which the stress was detected a predetermined time ago.

If sliding has occurred (Y in step S103), process S100 proceeds to step S104. If sliding has not occurred (N in step S103), process S100 ends.

In step S104, the output unit 103 outputs to an external device a signal that the railcar is skidding. This allows the external device to notify the user that skidding is occurring, making it possible to recognize that skidding is occurring.

After step S104, process S100 ends.

Conventionally, the detection results of axle speed sensors attached to each axle of each vehicle (four per vehicle) are compared, and skid of a railroad vehicle is detected based on the comparison result (e.g., speed difference). This conventional method requires collecting and comparing data from four axles, which imposes a large computational load, and the judgment of the detection of skid of each wheel depends on the detection results of the speed sensors attached to the other axles, which leaves room for improvement in terms of the accuracy of skid detection. In addition, freight cars and passenger cars towed by locomotives do not usually require anti-slip control during powering, so axle speed sensors are not installed. In order to further improve the accuracy of skid detection, it is expected that axle speed sensors will also be installed on the axles of these freight cars and passenger cars, but the installation is costly. Therefore, there is a demand for a technology that can detect skid at a lower cost for vehicles that do not have axle speed sensors installed.

On the other hand, in the third embodiment, the skid estimation unit 124 compares the detection result of the stress detection unit 30 with a reference value, and estimates whether or not skid is occurring in the railway vehicle based on the comparison result. With this configuration, since it is not necessary to compare the stress detection results of other axles to detect skid, it is possible to reduce the calculation load and improve the independence of skid detection, thereby further improving the accuracy of skid detection. In addition, skid can be detected at lower cost for vehicles that are not equipped with axle speed sensors, etc. Furthermore, two brake devices 1 are installed per axle. Therefore, skid can be determined using the detection results of two stresses per axle, and mutual monitoring can improve the accuracy of skid detection and suppress erroneous detection.

In the third embodiment, the stress detection result is compared with a reference value, but this is not limited thereto. The actual braking torque may be calculated from the stress detection result, and skid may be determined based on a comparison between the calculated actual braking torque and a reference value for the braking torque.

In the third embodiment, the output unit 103 outputs to an external device a signal that the railway vehicle is skidding, but this is not limited thereto, and may output a command to the brake device 1 to execute brake control to suppress skidding when it is estimated that the railway vehicle is skidding.

Fourth embodiment Hereinafter, a fourth embodiment of the present invention will be described. In the drawings and description of the fourth embodiment, the same or equivalent components and members as those of the first embodiment are denoted by the same reference numerals. Descriptions that overlap with the first embodiment will be omitted as appropriate, and the description will focus on the configurations that differ from the first embodiment.

Figure 12 is a functional block diagram of the processing device 100 in the brake device 1 of the fourth embodiment. The acquisition unit 101 of the fourth embodiment includes a stress acquisition unit 111 and a pressing force acquisition unit 112. The estimation unit 102 of the fourth embodiment includes an abnormality estimation unit 125 that estimates whether or not an abnormality has occurred in the brake device 1 based on the detection result of the stress detection unit 30 and the pressing force at the time of detection by the stress detection unit 30. The output unit 103 of the fourth embodiment outputs a notice to an external device when an abnormality has occurred in the brake device 1.

Figure 13 is a flowchart showing process S200 of the processing device 100 of the fourth embodiment. Process S200 is executed at a predetermined time interval (e.g., several milliseconds).

In step S201, the stress acquisition unit 111 acquires the detection result of the stress detection unit 30. The stress acquisition unit 111 supplies the acquired detection result to the abnormality estimation unit 125. After step S201, the process S200 proceeds to step S202.

In step S202, the pressing force acquisition unit 112 acquires the pressing force. The pressing force acquisition unit 112 supplies the acquired pressing force to the abnormality estimation unit 125. After step S202, the process S200 proceeds to step S203.

In step S203, the abnormality estimation unit 125 determines whether the brakes have been applied with a pressing force equal to or greater than a predetermined value. If the brakes have been applied with a pressing force equal to or greater than a predetermined value (Y in step S203), the process S200 proceeds to step S204. If the brakes have not been applied with a pressing force equal to or greater than a predetermined value (N in step S203), the process S200 ends.

In step S204, the abnormality estimation unit 125 determines whether the detection result of the stress detection unit 30 when the brake shoe 72 is pressed against the wheel 92 with a pressing force equal to or greater than a predetermined value is equal to or less than a predetermined stress threshold. If the detection result is equal to or less than the predetermined stress threshold (Y in step S204), the abnormality estimation unit 125 determines that an abnormality has occurred in the brake device 1, and processing S200 proceeds to step S205. If the detection result is not equal to or less than the predetermined stress threshold (N in step S204), the abnormality estimation unit 125 determines that no abnormality has occurred in the brake device 1, and processing S200 ends.

In step S205, the output unit 103 outputs to an external device that an abnormality has occurred in the brake device 1. As a result, for example, the external device is notified that an abnormality has occurred in the brake device 1.

After step S205, process S200 ends.

However, when a railway vehicle kicks up foreign objects such as snow, the foreign objects can become caught between the brake shoe 14 and the wheel 92. As a result, the coefficient of friction between the brake shoe 14 and the wheel 92 decreases, and it is thought that sufficient braking torque is not generated even though a pressing force is generated to apply the brakes.

In the fourth embodiment, the abnormality estimation unit 125 estimates whether or not an abnormality has occurred in the brake device 1 based on the detection result of the stress detection unit 30 and the pressing force at the time of detection by the stress detection unit 30. With this configuration, it is possible to grasp a state in which a foreign object such as snow is between the brake shoe 72 and the wheel 92, pressing the brake shoe 72 against the wheel 92 but not generating sufficient braking torque, and therefore it becomes possible to easily determine, for example, whether or not a snow-resistant brake can be used.

Fifth embodiment Hereinafter, a fifth embodiment of the present invention will be described. In the drawings and description of the fifth embodiment, the same or equivalent components and members as those of the first embodiment are denoted by the same reference numerals. Descriptions that overlap with the first embodiment will be omitted as appropriate, and the description will focus on the configurations that differ from the first embodiment.

Figure 14 is a diagram including a partial cross section of the brake device 2 according to the fifth embodiment. The brake device 2 of the fifth embodiment includes a brake mechanism 10, a holding portion 28, a base portion 36, and a stress detection portion 30.

In this embodiment, the brake mechanism 10 includes a caliper body 12. The base portion 36 functions as a base for mounting the brake mechanism 10 to the vehicle body 90. The base portion 36 is provided integrally with the actuator 20 described below.

The retaining portion 28 has a connected portion that is connected to the base portion 36 and a lever connection portion that is connected to the caliper body 12, and transmits stress to the stress detection portion 30. The stress detection portion 30 detects the stress in the rotational direction of the wheel 92 that is applied to the brake shoe during braking via the retaining portion 28.

Hereinafter, the extension direction of the axle 94 of the wheel 92 will be referred to as the "axial direction," and the circumferential direction and radial direction of the circle centered on the central axis La will be referred to as the "circumferential direction" and the "radial direction," respectively. In addition, hereafter, the side from one wheel 92 toward the axial center of the axle 94 in the axial direction will be referred to as the inner side, and the opposite side will be referred to as the outer side.

Figure 15 is a plan view showing the brake device 2 of the fifth embodiment in an exploded state. Figure 16 is a side view of the brake device 2 of the fifth embodiment. Figure 17 is a side view showing the brake device 2 of the fifth embodiment in an exploded state. Figures 15 and 17 show the main components, and omit members that are not important for the explanation. The brake mechanism 10 of this embodiment is a disc brake including a caliper body 12, a pair of brake shoes 14, a pair of back plates 15, and an actuator 20. The pair of brake shoes 14 are arranged to sandwich the brake disc (not shown) of the wheel 92, and function as brake pads that generate a braking force by being pressed against the wheel 92. The back plate 15 functions as a brake shoe holding portion that holds the brake shoes 14. The brake disc of the wheel 92 in this embodiment is an example of a friction material.

The caliper body 12 includes a pair of caliper levers 16 and a lever connecting member 18 that supports the fulcrum portions 16f of the pair of caliper levers 16 at positions spaced apart. The caliper levers 16 include an upper arm 16h that are connected to each other and a lower arm 16j that is disposed below the upper arm 16h. The upper arm 16h and the lower arm 16j each have a force point portion 16b provided at an end opposite the wheel and an output portion 16p provided at an end on the wheel side. The force point portion 16b is attached to the cylinder output portion of the actuator 20 via a cylinder pin 20p. The brake shoe 14, the pair of back plates 15, and the caliper levers 16 of this embodiment are an example of a transmission portion that transmits the pressing force input from the actuator 40 (drive portion) to the brake shoe 72.

The brake shoe 14 and the back plate 15 are attached to the output part 16p via a plate pin 15p. The plate pin 15p passes vertically through the mounting hole 15h of the back plate 15 and the hollow part 16q of the output side connection part 16n (described later), and a nut 15n is screwed onto the tip of the plate pin 15p.

The upper arm 16h and the lower arm 16j have a fulcrum portion 16f provided between the force point portion 16b and the output portion 16p. The force point portion 16b corresponds to the force point, the output portion 16p corresponds to the action point, and the fulcrum portion 16f corresponds to the fulcrum.

The upper arm 16h and the lower arm 16j are connected to each other by an intermediate connection part 16m and an output side connection part 16n. The intermediate connection part 16m is a part that extends vertically between the upper and lower force points 16b and the output part 16p. The output side connection part 16n is a cylindrical part that surrounds a hollow part 16q that extends vertically between the upper and lower output parts 16p.

The upper arm 16h and the lower arm 16j move together. Therefore, in the following description, the force point 16b, the fulcrum 16f, and the output part 16p refer to the upper and lower force points 16b, the upper and lower fulcrums 16f, and the upper and lower output parts 16p.

The fulcrum portion 16f is connected to both ends of the lever connecting member 18 via the fulcrum pin 18p. The lever connecting member 18 is an arm-shaped member extending in the axle direction, with the fulcrum portion 16f on the inside of the axle direction and the fulcrum portion 16f on the outside of the axle direction attached to both ends, maintaining a constant distance between the inside and outside fulcrum portions 16f. When a driving force is input from the actuator 20 to the force point portion 16b of the caliper body 12 configured in this manner, the output portion 16p presses the brake shoe 14 against the wheel 92 via the back plate 15, generating a braking force on the wheel 92.

The brake mechanism 10 is attached to the vehicle body 90 via the base portion 36. In this embodiment, the base portion 36 is attached to the vehicle body 90 with fasteners such as bolts (not shown), and the brake mechanism 10 is supported by the actuator 20 that is provided integrally with the base portion 36. The base portion 36 has a base connection portion 36e for attaching the connected portions 28e, 28f of the holding portion 28 described below. In this embodiment, the base connection portion 36e is a portion that protrudes inward in the axle direction from the side of the base portion 36, and has a base hole 36h that penetrates vertically.

From the viewpoint of ease of processing, it is desirable for the holding portion 28 to have a simple shape. For this reason, in this embodiment, the connected portions 28e and 28f are connected to the base connection portion 36e that protrudes from the base portion 36. In this case, the main body portion 28b of the holding portion 28 can be made closer to flat.

The actuator 20 will be described. FIG. 18 is a schematic plan view of the actuator 20 of the fifth embodiment. The actuator 20 may be any of various known brake actuators. The actuator 20 of this embodiment has a function of applying a braking force to a moving vehicle using the pressure of a working fluid. The actuator 20 may also have a function of applying a braking force to a parked vehicle using the biasing force of a biasing member, for example. The actuator 20 of this embodiment has a main body 20b, a push rod 20c that advances and retreats from the main body 20b in the axle direction, and a drive mechanism 20d that advances and retreats the push rod 20c. The actuator 20 is sometimes referred to as a brake cylinder device. The actuator 20 of this embodiment is an example of a drive unit.

The cylinder output section 20h is provided at the tip of the push rod 20c, and the cylinder output section 20j is provided on the surface of the main body section 20b opposite to the cylinder output section 20h. The force point section 16b of the caliper lever 16 is attached to the cylinder output sections 20h and 20j via the cylinder pin 20p. In other words, the push rod 20c functions as a member for transmitting the driving force of the actuator 20 to the caliper lever 16. The drive mechanism 20d advances and retreats the push rod 20c depending on the pressure state of the working fluid (e.g., air) supplied from a supply source (not shown), changing the separation distance in the axle direction between the two cylinder output sections 20h and 20j. In this example, the push rod 20c advances and retreats depending on the pneumatic state of the compressed air.

In the first air pressure state, as shown by the dashed line in FIG. 18, the push rod 20c protrudes and the distance between the cylinder output parts 20h, 20j increases. When the distance increases, the pair of force points 16b open, the output part 16p closes, the brake shoe 14 is pressed against the wheel 92, and a braking force is generated. In the second air pressure state, as shown by the solid line in FIG. 18, the push rod 20c retracts and the distance between the output parts 20h, 20j decreases. When the distance decreases, the pair of force points 16b close, the output part 16p opens, and the braking force is released. For example, the first air pressure state may be a higher pressure state than the second air pressure state.

It is desirable to position the cylinder output section 20h in a position that avoids interference with the holding section 28. For this reason, the actuator 20 in this embodiment is positioned so that a line extending from the axis of the push rod 20c passes through an opening 28d in the holding section 28, which will be described later.

The brake device 2 of this embodiment includes a retaining portion 28 connected to the caliper body 12 and a base portion 36 for mounting the caliper body 12 to the vehicle body 90, and a stress detection portion 30 that detects the stress transmitted by the retaining portion 28. With this configuration, one side of the retaining portion 28 is connected to the base portion 36, so that the brake device 2 includes a retaining portion 28 that is hardly affected by distortion caused by the cross-directional stress of the caliper lever 16. This reduces the effect of the cross-directional stress on the stress detection portion 30, improving measurement accuracy.

The brake device 2 of the fifth embodiment configured in this manner provides the same operational effects as the first embodiment. The processing device 100 of the fifth embodiment may execute the processing described above in the second to fourth embodiments. In this case, too, the same operational effects as the second to fourth embodiments are provided.

The present invention has been described above based on the embodiments. The embodiments are illustrative, and those skilled in the art will understand that various modifications are possible in the respective components and combinations thereof, and that such modifications are also within the scope of the present invention. Any combination of the above-mentioned embodiments and modifications is also useful as an embodiment of the present invention. A new embodiment resulting from a combination has the effects of both the combined embodiments and modifications. Among the embodiments disclosed in this specification, those in which multiple functions are provided in a distributed manner may have some or all of the multiple functions consolidated, and conversely, those in which multiple functions are provided in a consolidated manner may have some or all of the multiple functions distributed. Regardless of whether the functions are consolidated or distributed, it is sufficient that the configuration is such that the object of the invention can be achieved.

1, 2 Brake device, 10, 60 Brake mechanism, 20, 40 Actuator, 28, 73 Holding unit, 30 Stress detection unit, 72 Brake shoe, 92 Wheel, 100 Processing unit, 101 Acquisition unit, 102 Estimation unit, 103 Output unit, 104 Storage unit, 105 Deceleration determination unit, 106 Brake control unit, 107 Axle identification unit.

Claims (14)

a drive unit that is provided in a vehicle and generates a pressing force for pressing a friction material against a friction target material that rotates when the vehicle is running;
a transmission unit that transmits a pressing force input from the drive unit to the friction material;
a holding portion that holds the transmission portion on a body of the vehicle;
a stress detection unit provided in the holding unit, the stress detection unit detecting a stress generated in the holding unit when the friction material is pressed against the rotating friction target material to generate a braking torque for braking the vehicle;
an estimation unit that estimates at least one of a friction coefficient between the friction material and the frictioned material and a skid of the vehicle based on a detection result of the stress;
A vehicle brake device comprising: A pressing force acquisition unit that acquires the pressing force is further provided,
The estimation unit estimates the friction coefficient based on the detection result of the stress detection unit and the pressing force.
2. A vehicle brake device according to claim 1. a speed information acquisition unit that acquires speed information including at least one of a speed of the vehicle and a rotational speed of the friction-receiving material at a time point detected by the stress detection unit,
the estimation unit estimates the friction coefficient based on the detection result of the stress detection unit, the pressing force, and the speed information.
3. A vehicle brake device according to claim 2. a storage unit that stores correspondence information indicated by a predetermined correspondence relationship between a pressing force when the friction material is pressed against the friction-receiving material under a predetermined condition, the speed information when the friction material is pressed against the friction-receiving material with the pressing force, and at least one of the friction coefficient and the braking torque when the friction material is pressed against the friction-receiving material with the pressing force;
The estimation unit estimates the friction coefficient based on the detection result of the stress detection unit and the correspondence information.
4. A vehicle brake device according to claim 3. The estimation unit is
an actual braking torque calculation unit that calculates an actual braking torque that is actually generated in the friction target material based on a detection result of the stress detection unit;
an assumed braking torque calculation unit that calculates an assumed braking torque that is assumed to have occurred in the friction target material based on the correspondence information and the pressing force and the speed information at the time of detection by the stress detection unit;
a comparison unit that estimates the friction coefficient based on a comparison result between the actual braking torque and the assumed braking torque;
Equipped with
5. A vehicle brake device according to claim 4. a tilt angle acquisition unit that acquires a tilt angle of a track on which the vehicle runs at a time point detected by the stress detection unit,
the estimation unit estimates the friction coefficient based on a detection result of the stress detection unit, the pressing force, and the tilt angle.
3. A vehicle brake device according to claim 2. the vehicle is a rail vehicle that runs on a track,
a running position acquisition unit that acquires a running position of the railcar at a time point detected by the stress detection unit;
an output unit that associates the friction coefficient estimated by the estimation unit with the traveling position at the time of detection by the stress detection unit and outputs the result to an external device;
Further comprising:
3. A vehicle brake device according to claim 2. An environmental information acquisition unit that acquires environmental information including at least one of weather, temperature, and humidity at a traveling position of the vehicle at a time point detected by the stress detection unit,
the estimation unit estimates the friction coefficient based on a detection result of the stress detection unit, the pressing force, and the environmental information.
3. A vehicle brake device according to claim 2. an environmental information acquisition unit that acquires environmental information including at least one of weather, temperature, and humidity at a traveling position of the vehicle at a time point detected by the stress detection unit;
an output unit that associates the friction coefficient estimated by the estimation unit with at least one of the weather, the temperature, and the humidity at the time of detection by the stress detection unit and outputs the result to an external device;
Further comprising:
3. A vehicle brake device according to claim 2. The friction material is a wheel,
an axle identification unit that identifies an axle of the wheel for which the friction coefficient has been estimated, among a plurality of axles provided on the vehicle;
A driving direction acquisition unit that acquires a driving direction of the vehicle;
an output unit that outputs to an external device the detection result of the stress detection unit, the friction coefficient estimated by the estimation unit, and the wheel whose friction coefficient was estimated, in association with each other;
Further comprising:
3. A vehicle brake device according to claim 2. the estimation unit includes a slide estimation unit that compares a detection result of the stress detection unit with a reference value and estimates whether or not a slide is occurring in the vehicle based on a comparison result between the detection result of the stress detection unit and the reference value .
2. A vehicle brake device according to claim 1. The reference value is a detection result of the stress detection unit from a predetermined time ago.
A vehicle brake system according to claim 11. a drive unit that is provided in a vehicle and generates a pressing force for pressing a friction material against a friction target material that rotates when the vehicle is running;
a transmission unit that transmits a pressing force input from the drive unit to the friction material;
a holding portion that holds the transmission portion on a body of the vehicle;
a stress detection unit provided in the holding unit, the stress detection unit detecting a stress generated in the holding unit when the friction material is pressed against the rotating friction target material to generate a braking torque for braking the vehicle;
an abnormality estimation unit that estimates whether or not an abnormality has occurred in the vehicle brake device based on a detection result of the stress detection unit and a pressing force of the friction material at a time point of detection by the stress detection unit;
A vehicle brake device comprising: The friction material is a wheel,
the holding portion includes an attachment portion connected to the vehicle body, and a link portion rotatably connected to each of the attachment portion and the transmission portion,
The stress detection unit detects a longitudinal stress generated in the link portion when the braking torque is generated.
A vehicle brake device according to any one of claims 1 to 13.

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