Method for detecting brake status, brake, and brake system with brake

Abstract

A method for detecting the state of a brake, a brake, and a brake system provided with such a brake. There is provided a method for detecting the state of a brake (2), a brake, and a brake system provided with such a brake. The method includes the steps of moving an actuating member (9) of a brake actuator (6) in a direction in which a friction element (5) coupled to the actuating member (9) is moved in an actuating direction toward a braking target element (4), and detecting a position of the actuating member (9) as a first corner position at which contact of the friction element (5) with the braking target element (4) is identified by a force starting to increase.

Description

Technical Field

[0001] The present invention relates to a method for detecting the state of a brake, a brake, and a brake system provided with the brake, particularly in relation to railway vehicles.

[0002] The identification of wear of the friction material in a disc brake, i.e., wear of the brake disc and brake pads, has hitherto generally been carried out in the field of railway vehicles by visual inspection by maintenance personnel, but this involves significant costs.

[0003] However, wear of the friction material can also be measured by an image processing device ("train scanner") incorporated in a fixed position on the track bed, or by sensors incorporated in the vehicle or its brake controller. However, the use of an image processing device incurs significant costs and, as described above, has the problem of being fixed in position and thus not flexible. These sensors also involve significant costs and are more prone to failure.

[0004] Another possibility for identifying wear of the friction material is a wear calculation program that uses system parameters identified from measured quantities, such as braking force and vehicle speed, to calculate wear based on a model based on the converted braking energy. However, these calculations can be very inaccurate.

[0005] The function of the wear adjustment device for ensuring the brake despite wear can only be confirmed when the required braking action can no longer be obtained.

[0006] Therefore, the underlying problem of the present invention is to solve the above-mentioned drawbacks and provide a method and a brake for identifying the state of the brake in a cost-effective and reliable manner.

[0007] This problem is solved by the method described in claim 1, the brake described in claim 10, and the brake system described in claim 13. Advantageous developments are included in the dependent claims.

[0008] According to one aspect of the present invention, a method for detecting the brake state is to follow these steps: - A step of moving the working member of the brake actuator in a direction that causes the friction element coupled to the working member to move toward the element to be braked in the direction of action, - The method includes a step of detecting the position of the working member as the first corner position, where contact of the friction element with the element to be braked is identified as the force on the working member begins to increase.

[0009] These steps establish a foundation for detecting the brake state without requiring additional sensors to be incorporated into the brake controller, and in particular without requiring such sensors in the area of ​​the braking element, i.e., the brake disc area, and in the area of ​​the braking element, i.e., the brake pad area.

[0010] Electromechanical drive systems, as drive devices, have position measuring units and force measuring units. For example, position can be determined indirectly via the rotation of the motor. In electrically rectified DC motors, an angle sensor is required. The position of the brake cylinder can be estimated via the rotation of the motor and the gear ratio of the working member. Measuring the force of the brake cylinder is necessary in railway vehicle braking systems to control the braking force, where the force of the brake cylinder is determined in electromechanical brake systems via a specific force sensor or via motor torque. Motor torque can be determined via phase current, which is usually a known quantity. In the case of pneumatic or hydraulic cylinders, corresponding sensors can be provided in or in the braking mechanism.

[0011] In one advantageous embodiment of the method, where the distance of the working member from its stationary position to the first corner position corresponds to the relevant spacing of the friction elements from the element being braked, wear is compensated so that the relevant spacing is within a predetermined tolerance. This embodiment of the method includes the next step of determining the functionality of the wear adjustment device by determining, after a predetermined number of braking processes, that the relevant spacing is within a predetermined tolerance via the distance of the working member.

[0012] After a predetermined number of braking processes, if it is determined that a predetermined interval is within a predetermined tolerance range via the distance of the working member from the actuator's stationary position to the first corner position, then the functionality of the adjustment mechanism, i.e., the assurance of adjustment and, consequently, the reliable deceleration of the railway vehicle, can be determined.

[0013] In another advantageous embodiment of this method, the method proceeds to the following steps, namely, - In order to form a braking process, the step of continuing the movement of the working member and the friction element coupled to the working member in the direction of action, - A step of moving the working member and the friction element coupled to the working member in the opposite direction to the direction of action in order to terminate the braking process, - The method includes a step of detecting the position of the working member as the second corner position, where the lifting of the friction element from the braking target element is identified when the reduction in force on the working member ends.

[0014] These additional steps establish a basis for detecting other brake states without the need to incorporate additional sensors into the brake controller, particularly in the area of ​​the braking element, especially the area of ​​the brake disc, and without requiring such sensors in the area of ​​the braking element, especially the brake pad.

[0015] In one advantageous embodiment of the present method, the method includes the following step: determining the wear of the friction element and the braking element by calculating the difference in position between the first corner position and the second corner position.

[0016] In this case, for example, it is possible to identify the wear that actually occurs during the final braking process of the friction element and the element being braked, without the need to install sensors or image processing devices in the friction element. In this case, the wear state of the entire friction material is identified. From empirical data, the wear distribution of the element being braked and the friction element can be identified.

[0017] In another advantageous embodiment of the present method, the method includes the following step: determining the total wear of the friction element and the element being braked by summing up the wear of the friction element and the element being braked after a series of braking processes.

[0018] This step makes it possible, for example, to identify overall wear since the replacement of friction materials in order to signal preventative maintenance.

[0019] In another advantageous embodiment of this method, the total wear of the friction element and the element being braked is determined after each braking process.

[0020] This makes it possible to accurately determine the wear progression even under ambient conditions where, for example, the speed or weight of a railway vehicle is detected.

[0021] In another advantageous embodiment of the method, the method includes the following step: determining the thermal expansion of the friction element and the damping element by calculating the difference in position between the first corner position and the second corner position.

[0022] By identifying the thermal expansion of friction elements and braking elements, and by determining the overall expansion of both elements, it is possible to estimate, for example, the thermal load of a brake.

[0023] In another aspect of the present invention, the brake comprises a brake actuator, a friction element, and a braking target element having a brake actuator and configured to move the friction element toward the braking target element in the direction of action for a braking process, depending on the movement of the working member of the brake actuator, and to move the friction element away from the braking target element in the opposite direction of action to terminate the braking process, wherein the brake actuator is configured to detect, via a braking mechanism, the force exerted on the friction element along the direction of action and the position of the friction element along the direction of action, using the force exerted on the working member of the brake actuator and the position of the working member.

[0024] This brake allows for the detection of the brake state without requiring additional sensors or image processing devices in the area of ​​the braking element, particularly the brake disc, or in the area of ​​the braking element, especially the brake pad.

[0025] In a favorable embodiment of the brake, the brake is configured to implement the method described above, thereby achieving the advantages mentioned above.

[0026] In another advantageous embodiment of the brake, in which the braking mechanism has a wear compensator, the brake is configured to perform one of the aforementioned methods with wear compensation, thereby achieving the advantages described above.

[0027] According to another aspect of the present invention, the brake system comprises a brake and a control device configured to drive and control the brake, the control device being configured to evaluate and process the detected first corner position and second corner position.

[0028] Hereinafter, the present invention will be described based on embodiments with reference to the accompanying drawings.

Brief Explanation of Drawings

[0029] [Figure 1] It is a basic diagram of a brake system equipped with an electromechanical brake. [Figure 2] It is a basic diagram of the piston position and piston force of the electromechanical brake actuator of the electromechanical brake when there is no brake wear. [Figure 3] It is a basic diagram of the piston position and piston force when there is brake wear. [Figure 4] It is a basic diagram of the piston position when adjusting after brake wear. [Figure 5] It is a basic diagram of the piston position when the electromechanical brake thermally expands.

[0030] In FIG. 1, a basic diagram of a brake system 1 equipped with an electromechanical brake 2 and a control device 3 is shown. In an alternative embodiment, the brake is configured as a pneumatic brake or a hydraulic brake instead of an electromechanical brake.

[0031] The electromechanical brake 2 has a brake disk as a braking target element 4 and a brake pad as a friction element 5. The electromechanical brake 2 further has an electromechanical brake actuator 6 coupled to the braking mechanism 7 and the wear adjustment device 8 of the electromechanical brake 2 by an eccentric shaft. In an alternative embodiment, the brake disk may be replaced by a wheel body or a brake drum. In another alternative embodiment, only one friction element 5 is provided or more than two friction elements 5 are provided. Correspondingly, in an alternative embodiment where the brake is configured as a pneumatic brake or a hydraulic brake, a pneumatic brake actuator or a hydraulic brake actuator is provided.

[0032] In this embodiment, the electromechanical brake actuator 6 is implemented as an electromechanical cylinder with a piston rod as the working member 9. In an alternative embodiment, the electromechanical brake actuator 6 may be implemented as, for example, a rotary cylinder. The position of the piston rod is determined indirectly via an angle sensor through the rotation of the motor of the electromechanical brake actuator 6, and the position of the brake cylinder is estimated via the rotation of the motor and the gear ratio of the working member. In an alternative embodiment, the position of the working member 9 can also be detected via a distance sensor in a pneumatic or hydraulic cylinder, or at another location in the braking mechanism 7, for example, on an eccentric body described later.

[0033] As the piston rod extends, an eccentric body is deflected via a lever, and this eccentric body is supported within the braking mechanism 7 such that a friction element 5 directly coupled to the eccentric body is moved toward the braking target element 4 in the direction of action. When this friction element 5 is supported by the braking target element 4, as the piston rod continues to extend, the entire braking mechanism 7 is shifted, and the other friction element 5 is also moved toward the braking target element 4 in its direction of action and makes contact there. As the piston rod continues to extend further, the braking force of the electromechanical brake 2 is formed during the braking process. To end the braking process, the piston rod retracts again into the electromechanical brake actuator 6, thereby moving the friction element 5 away from the braking target element 4.

[0034] On the one hand, the electromechanical brake actuator 6 is driven and controlled by the control device 3 to generate the required braking force. On the other hand, the electromechanical brake actuator 6 uses the force exerted on the working member 9 of the electromechanical brake actuator and the position of the working member 9 to supply data to the control device 3 about the force exerted on the friction element 5 along the direction of action and the position of the friction element 5 along the direction of action. In an alternative embodiment, this data is supplied to a separate evaluation device rather than to the control device 3 that drives and controls the electromechanical brake actuator 6. In another alternative embodiment, the control device 3 is integrated into the electromechanical brake actuator 6. In yet another alternative embodiment, the position and force data are supplied not by the electromechanical brake actuator 6 but by sensors in the braking mechanism 7.

[0035] The wear adjustment device 8 identifies the point in time when the braking element 4 and / or friction element 5 wear down and automatically compensates for the wear as is known in the prior art. Wear compensation is performed when the friction element 5 moves toward the braking element 4 or when the friction element 5 moves away from the braking element 4.

[0036] Figure 2 shows a basic diagram of the piston position and piston force of the piston as the operating member 9 of the electromechanical brake actuator 6 of the electromechanical brake 2, when there is no brake wear.

[0037] The upper bar graph shows the piston position, that is, the distance of the working member 9, depending on its action.

[0038] Starting from the piston position of 0 mm, which is the stationary position of the working member 9, the idle stroke LH is performed up to the extended piston position of 17 mm. The idle stroke LH is the stroke that the piston must travel from the stationary position in order to bring the friction element 5 into contact with the braking target element 4.

[0039] Following the idle stroke LH, the so-called elastic stroke EH takes place. The elastic stroke EH is the stroke by which the piston must travel to compensate for the elasticity of the brake system when forming a force between the friction element 5 and the braking element 4. The elasticity of the brake system is a nearly constant, particularly linear, system characteristic. The elastic stroke EH depends on the braking force, and in this embodiment it is 22 mm. The braking process is carried out by the elastic stroke EH.

[0040] To terminate the braking process, an elastic stroke-EH is performed again in the opposite direction with a piston stroke of 22 mm, followed by another piston stroke of 17 mm as the opposite idle stroke-LH, thereby returning the friction element 5 to its original position and the piston as the working member 9 to its original resting position.

[0041] The lower graph shows the piston force progression depending on the piston position. The force-distance progression is shown by the thick solid line. For illustrative purposes, the idle stroke LH, -LH and elastic stroke EH, -EH are shown next to the thick solid line, but in reality they are located on the thick solid line. As with the upper graph, it can be seen here that the idle stroke LH occurs up to the piston position of 17 mm, during which no force is applied to the friction element 5, and consequently the piston force remains "0". As soon as the friction element 5 and the braking element 4 come into contact, the piston force increases during the elastic stroke EH. The piston position where the friction element 5 contacts the braking element 4, i.e., where the piston force begins to increase, is called the first corner position. In this case, the piston is extended by 22 mm to the piston position of 39 mm in order to achieve the currently desired braking force. To terminate the braking process, the friction element 5 is moved in the opposite direction, which reduces the piston force again to the piston position where the friction element 5 is lifted away from the braking element 4, thereby reducing the piston force back to "0". The piston position where the friction element 5 is lifted away from the braking element 4, i.e., where the piston force remains constant at "0", is called the second corner position. In other words, in the absence of wear, the second corner position coincides with the first corner position.

[0042] In other words, the position of the first corner is detected by detecting when the force begins to increase. The position of the second corner is detected by detecting the passage of a constant force after the force has decreased.

[0043] The force path is idealized here and shown as a straight line. However, in reality, the force path has an unstable course due to the friction and inertia of the components involved, and this course is smoothed and / or averaged by the corresponding algorithm in order to make it quantifiable.

[0044] Figure 3 shows a basic diagram of piston position and piston force when brake wear is present.

[0045] As can already be seen in the graph in Figure 2, an idle stroke LH is performed up to a piston position of 17 mm, followed by an elastic stroke of 22 mm, i.e., up to a piston position of 39 mm. For example, during relatively long downhill driving, due to a relatively long braking process, the friction element 5 and / or the braking target element 4 wear down, and as a result, an additional wear stroke VH is required to maintain the necessary braking force. The wear stroke VH is the stroke that the piston must travel to compensate for the wear of the friction material, i.e., the friction element 5 and the braking target element 4, during braking, so that the desired braking force is maintained. In this embodiment, the wear stroke VH is 3 mm, i.e., up to a piston stroke of 42 mm. In this case, in order to end the braking process, the friction element 5 is moved again in the opposite direction, thereby reducing the piston force again until the piston position where the friction element 5 is lifted away from the braking target element 4. The 22mm elastic stroke EH / -EH is a constant system characteristic; that is, the friction element 5 is lifted from the braking element 4 at a piston position of 20mm, which is the second corner position. Subsequently, the working member 9 travels back to the stationary position, here traveling 20mm, i.e., a distance of 17mm for -LH and a distance of 3mm for -VH. In this case, the second corner position is 3mm different from the first position, which corresponds to the wear stroke VH and corresponds to the wear of the braking element 4 and the friction element 5.

[0046] Figure 4 shows a basic diagram of the piston position after adjustment following brake wear.

[0047] The illustration in the upper bar graph corresponds to the illustration in the upper bar graph of Figure 3, and therefore wear occurs on the braking target element 4 and friction element 5 during braking. What can be seen here is that the return stroke-LH-VH corresponds to -20 mm, and therefore the wear corresponding to the piston distance of 3 mm has not yet been compensated for. Following this braking process, the next braking process, which is essentially already shown in Figure 2, takes place as illustrated in the lower bar graph.

[0048] In the lower graph of Figure 4, the idle stroke LH is similarly 17 mm, which indicates that the wear from the last braking process during the idle stroke LH was compensated for by the wear adjuster 8 for the next braking process, thereby making the idle stroke LH correspond to the typical idle stroke LH of 17 mm. Alternatively, the wear adjuster 8 may already compensate for the wear during the return stroke-LH-VH, in which case the return stroke-LH may also be 17 mm. Alternatively, the wear may be compensated partly during the return stroke-LH and partly during the idle stroke LH in the next braking process.

[0049] Figure 5 shows a basic diagram of the piston position when an electromechanical brake undergoes thermal expansion.

[0050] In this figure as well, the first part of the braking process corresponds to the braking process shown in Figures 3, 4, and 5 until the desired braking action is achieved. First, an idle stroke LH of 17 mm piston stroke is performed, followed by an elastic stroke EH of 22 mm.

[0051] During the braking process, thermal expansion occurs in the electromechanical brake 2, particularly in the friction element 5 and the braking target element 4, due to kinetic energy converted into heat. Because this expansion increases the braking force, the electromechanical brake actuator 6 is driven and controlled to retract its working member 9 by a so-called expansion stroke AH in order to reduce the braking force to the actual required level. Thus, the expansion stroke AH is the stroke that the piston must travel in order to maintain a constant brake operating force as a result of thermal expansion. In this embodiment, the expansion stroke is -7 mm.

[0052] As can be seen from the following bar, the elastic stroke-EH is 22mm in this case as well, with nearly constant system characteristics. Therefore, the return stroke from the second corner position is obtained from the idle stroke-LH, which is reduced by the expansion stroke AH.

[0053] However, this expansion stroke AH is not compensated for, and the original state is restored by the cooling of the components of the electromechanical brake 2, so that the idle stroke LH shown in the lower bar graph becomes 17 mm again during the next braking process.

[0054] During operation, the following method is used to detect the state of the electromechanical brake. Corresponding to the stroke shown in Figures 2 to 5, the operating member 9 of the electromechanical brake actuator 6 is moved in a direction that moves the friction element 5 coupled to the operating member 9 toward the element to be braked 4 in the direction of action. As the force in the operating member 9 begins to increase, contact of the friction element 5 with the element to be braked 4 is identified, and the position of the operating member 9 is detected as the first corner position, and the movement of the friction element 5 continues in the direction of action to form the braking process. To end the braking process, the friction element 5 is moved in the opposite direction of action. As a result, the force in the operating member 9 also decreases, and as the decrease in force in the operating member ends, the lifting of the friction element 5 away from the element to be braked 4 is identified, and the position of the operating member 9 is detected as the second corner position. Using these two corner positions, the state of the electromechanical brake can be detected.

[0055] By calculating the difference in position of the working member 9 at the first corner position and the second corner position, wear of the friction element 5 and the braking element 4 can be identified. If there is no difference in position between the first corner position and the second corner position, this indicates that no significant wear occurred during the final braking process.

[0056] In addition to identifying wear during a single braking process, total wear can also be determined by adding up the wear of the friction element 5 and the braking element 4. To determine total wear as accurately as possible, this total wear is determined after each braking process. In an alternative embodiment, this total wear is determined after a predetermined number of braking processes, or, for example, after a predetermined duration has elapsed.

[0057] If the wear of the friction element 5 and the braking element 4 exceeds a predetermined limit, the wear is automatically compensated using the wear adjustment device 8. In this embodiment, this is done via automatic mechanical drive control of the wear adjustment device 8 within the braking mechanism 7. In an alternative embodiment, this drive control may be performed pneumatically, or the wear adjustment device can be driven and compensated for by using the identification of the wear of the friction element 5 and the braking element 4 using the first and second corner positions.

[0058] As already explained above, this compensation can be performed on the braked element 4 of the next braking process during the return stroke of the friction element 5 after it has been lifted from the braked element 4, or during the idle stroke LH of the friction element 5. Furthermore, it is also possible to perform partial compensation during the return stroke-LH and partially during the idle stroke LH of the subsequent braking process. Alternatively, the compensation may not be performed immediately, but rather in one control process of the next multiple braking processes, or during multiple braking processes of the next multiple braking processes, provided that it is guaranteed that the wear will not cause functional damage.

[0059] The distance of the working member 9 from its stationary position to the first corner position corresponds to the relevant spacing of the friction element 5 from the braking element 4, and this wear is compensated so that this spacing is within a predetermined tolerance range. In an alternative embodiment, wear is always compensated to a predetermined extent, rather than being associated with a predetermined tolerance range.

[0060] When wear is compensated so that the interval is within a predetermined tolerance range, it is possible to determine the functionality of the wear adjustment device 8 via the distance of the working member 9 from the stationary position to the first corner position by determining that, after a predetermined number of braking processes, the relevant interval is within a predetermined tolerance range. Alternatively, it is also possible to determine the functionality of the wear adjustment device 8 via only the first corner position, without determining the wear of the friction element 5 and the braking element 4 via the first and second corner positions.

[0061] Furthermore, by calculating the positional difference between the first corner position and the second corner position before and after the braking process, it may be possible to determine the overall thermal expansion of the friction element 5 and the braking target element 4.

[0062] While the present invention has been described in relation to specific features and embodiments, it is evident that various modifications and combinations thereof can be made without departing from the spirit and scope of the invention. Therefore, the description and drawings should be considered merely a description of the invention as defined by the appended claims and should cover all modifications, variations, combinations, or equivalents that fall within the scope of the invention. [Explanation of symbols]

[0063] 1. Brake System 2. Electromechanical brakes 3. Control device 4 Braking target elements 5 Friction element 6. Electromechanical brake actuator 7 Braking mechanism 8. Wear adjustment device 9 Operating Members LH,-LH Idle Stroke EH,-EH Elastic stroke VH wear stroke AH Expansion Stroke

Claims

1. A method for detecting the state of a brake (2) for a railway vehicle, the following steps: A step of moving the operating member (9) of the brake actuator (6) in a direction such that the friction element (5) coupled to the operating member (9) of the brake actuator (6) is moved toward the braking target element (4) in the direction of action, The step of detecting the position of the working member (9) as the first corner position, where the contact of the friction element (5) with the braking target element (4) is identified as the force begins to increase, To form a braking process, the steps include continuing the movement of the working member and the friction element (5) coupled to the working member in the direction of action, To terminate the braking process, the step of moving the working member and the friction element (5) coupled to the working member in the opposite direction to the direction of action, The steps include detecting the position of the acting member (9) as the second corner position, where the lifting of the friction element (5) from the braking target element (4) is identified as the completion of the force reduction, The steps include: determining the wear of the friction element (5) and the braking target element (4) by calculating the difference in position between the first corner position and the second corner position; A method having

2. The distance of the operating member (9) from its stationary position to the first corner position corresponds to the relevant distance of the friction element (5) from the braking target element (4), and compensates for wear of the friction element (5) and the braking target element (4) so ​​that the relevant distance is within a predetermined tolerance range, and then proceeds to the next step, i.e., The method according to claim 1, further comprising the step of determining the functionality of the wear adjustment device (8) for automatically compensating for the wear by determining, after a predetermined number of braking processes, that the relevant interval is within the predetermined tolerance range via the distance of the working member (9).

3. The method according to claim 1, further comprising the step of determining the total wear of the friction element (5) and the braking target element (4) by adding up the wear of the friction element (5) and the braking target element (4) after a plurality of braking processes.

4. The method according to claim 3, wherein the total wear of the friction element (5) and the braking target element (4) is determined after each braking process.

5. The method according to claim 4, wherein the wear is at least partially compensated as the friction element (5) moves away from the braking target element (4).

6. The method according to claim 3, wherein the friction element (5) moves toward the braking element (4) and at least partially compensates for the wear.

7. The method according to claim 1, further comprising the step of determining the thermal expansion of the friction element (5) and the braking target element (4) by calculating the difference in position between the first corner position and the second corner position.

8. A brake system (1) having a brake (2) for a railway vehicle and a control device (3) configured to drive and control the brake (2), The aforementioned brake (2) is Brake actuator (6) and Friction element (5), Braking target element (4), A braking mechanism (7) having a brake actuator (6), and configured to move the friction element (5) toward the element to be braked (4) in the direction of action for the braking process, depending on the movement of the operating member (9) of the brake actuator (6), and to move the friction element (5) toward the element to be braked (4) in the opposite direction of action to terminate the braking process, wherein the braking mechanism (7) has a wear adjustment device (8), The braking mechanism (7) is configured to detect the force exerted on the friction element (5) along the direction of action and the position of the friction element (5) along the direction of action, using the force exerted on the working member (9) of the braking mechanism (7) and the position of the working member (9). The control device (3) is configured to carry out the method described in any one of claims 1 to 7. Brake system (1).

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