SYSTEM FOR MONITORING THE ROTATION OF AT LEAST ONE AXIS

Abstract

A rotation monitoring system for at least one axis (WRM) designed to identify at least one axis controlled by it having an estimated instantaneous linear speed lower than a predetermined instantaneous linear limit speed, and to remove the braking force to one or more wheels of the axis identified as having an estimated instantaneous linear speed lower than the predetermined instantaneous linear limit speed, by canceling pressure to the brake cylinders associated with at least one axis identified as having an estimated instantaneous linear speed lower than the predetermined instantaneous linear limit speed.The cancellation of pressure is achieved by actuating an electropneumatic valve (20) designed to perform a remote release function associated with the pneumatic circuits that generate braking pressure for the brake cylinders and adapted to cancel residual braking pressure.

Description

1 / 14 “SYSTEM FOR MONITORING ROTATION OF AT LEAST ONE AXIS” Field of Invention

[001] The present invention relates generally to the field of railway braking systems; in particular, the invention relates to a rotation monitoring system for at least one axle of a railway vehicle or train. Background of the Invention

[002] In the rail transport system, the instantaneous adhesion value between the wheel and the rail represents the maximum limit of braking force currently applicable to the axles without the wheels of said axles initiating a progressive slip phase.

[003] If an axle enters the slipping phase, if the applied braking force is not quickly and adequately reduced, the axle gradually loses angular velocity until it reaches complete locking, with the consequent immediate overheating and serious damage due to the excessive temperature of the axle wheel surface at the point of contact between the wheels and the rail.

[004] It is known that the situation we have just described, in addition to significantly increasing stopping distances due to a greater reduction in the coefficient of friction, can cause derailment at high operating speeds of the railway vehicle.

[005] To overcome the described inconvenience, pneumatic railway braking systems are equipped with a protection system, known as an anti-skid system.

[006] A known anti-skid system is illustrated by way of example in Figure 1, in the case of a four-axle rail vehicle (102, 103, 104, 105). A braking system (110) produces the braking pressure. Petition 870230021695, dated 03 / 14 / 2023, page 9 / 31 2 / 14 pneumatic as a function of a braking pressure or braking force request, not shown in Figure 1, supplying the brake cylinders (111, 112, 113, 114).

[007] Each brake cylinder (111, 112, 113, 114) is responsible for braking a respective axle (102, 103, 104, 105), by means of pneumatic ducts (115, 116). Four anti-slip valve units (117, 118, 119, 120), piloted by the anti-slip device (101), are interposed between the pneumatic supply ducts (115, 116) and the respective brake cylinders (111), (122) and (113), (114).

[008] Angular velocity sensors (106, 107, 108, 109) detect the angular velocity of the shafts (102, 103, 104, 105), respectively. The aforementioned angular velocity sensors (106, 107, 108, 109) are electrically connected to the anti-slip device (101), continuously providing an electrical signal that represents the instantaneous angular velocity information of each shaft (102, 103, 104, 105).

[009] The anti-slip device (101) continuously estimates the instantaneous linear speed of the vehicle by means of operations performed on the estimated instantaneous linear speed information of the axles (102, 103, 104, 105) derived from the relative measured angular velocities.

[010] By continuously evaluating the AV differences between the estimated instantaneous linear speed of the single axle and the estimated instantaneous linear speed of the vehicle, the anti-slip device (101) detects whether one or more axles have initiated a slip phase. If one or more axles have initiated a slip phase, the anti-slip device controls the slip of said axles by appropriately reducing and modulating the pressure to the brake cylinders relative to the slipping axles, acting on the valve units related to said slipping axles by means of known algorithms, for example described in EP 3393873, WO Petition 870230021695, dated 03 / 14 / 2023, page 10 / 31 3 / 14 2017175108, preventing the aforementioned axles from entering a locked state and attempting to obtain the best braking force while remaining in the sliding phase.

[011] The aforementioned anti-slip valve units (117, 118, 119, 120) can each assume the detailed form represented by the pair of electropneumatic valves (220, 221), illustrated in Figure 2.

[012] The electropneumatic valves (220, 221) are energized by the anti-slip device (201) by means of the respective switching elements (202, 203). These switching elements (202, 203) are typically solid-state electronic components.

[013] For simplicity of illustration, Figure 2 does not show the connection of solenoids, i.e., electrical coils, (204, 205) to ground.

[014] The anti-slip valve units (117, 118, 119, 120) can assume four general states.

[015] The first state is defined as “filling” and corresponds to a state in which both electropneumatic valves are de-energized, as shown in Figure 2: the electropneumatic valve (220) allows access to the pressure present in a pneumatic conduit (215), corresponding to the pneumatic conduit (115, 116) of Figure 1, to a brake cylinder (211), corresponding to the brake cylinder (111, 112, 113, 114) of Figure 1, while the electropneumatic valve (221) prevents the emptying of the brake cylinder (211) and the pneumatic conduit (215) to the atmosphere. This state represents the state of rest, or non-intervention, of the anti-slip device, since it actually constitutes a direct connection between the brake cylinder (211) and the pneumatic conduit (215), through which the brake system directly controls the pressure to the brake cylinder (211) from a zero value to a maximum value.

[016] The second state is defined as “retaining” and corresponds Petition 870230021695, dated 03 / 14 / 2023, page 11 / 31 4 / 14 to a state in which the electropneumatic valve (220) is energized. In this case, the pressure in the brake cylinder (211) cannot be altered by pressure variations in the pneumatic conduit (215). The electropneumatic valve (221) continues to keep the brake cylinder (211) isolated from the atmosphere. In general, the pressure to the brake cylinder (211) maintains its value indefinitely, unless there are leaks in the brake cylinder.

[017] The third state is defined as “discharge” and corresponds to a state in which both electropneumatic valves (220, 221) are energized. In this case, the pressure in the brake cylinder (211) cannot be altered by pressure variations in the pneumatic conduit (215). The energized electropneumatic valve (221) connects the brake cylinder (211) to the atmosphere, reducing the pressure to the brake cylinder, possibly to zero.

[018] The fourth state is defined as “forbidden” and corresponds to a state in which only the electropneumatic valve (221) is energized. In this case, the electropneumatic valve connects the brake cylinder (211) and the pneumatic conduit (215) directly to the atmosphere, causing an undue discharge to the atmosphere of the pressure produced by the brake system.

[019] Anti-slip devices are regulated by European railway regulations: UIC541-05 “Brakes - Specifications for the construction of various brake components - Wheel slip protection device (WSP)”; and EN15595 “Railway applications - Braking - Wheel slip protection”.

[020] Both standards pay close attention to the case where the railway train may be operated at speeds above 200 km / h. In particular, EN15595 §4.2.4.3 “Special characteristics of WSP systems for high speeds (v > 200 km / h)” and subchapters, recommends the use of a Petition 870230021695, dated 03 / 14 / 2023, page 12 / 31 5 / 14 “Wheel Rotation Monitoring” device, that is, to monitor the rotation of the wheels, responsible for verifying that the estimated instantaneous linear speed of the single axle, derived from its instantaneous angular speed, does not fall below an instantaneous linear limit speed, which is a function of the reference linear speed of a vehicle, for more than 10 seconds.

[021] In addition, in §4.2.4.3.3 “Recommended features”, it is recommended that the Wheel Rotation Monitoring device be equipped with the functionality to be able to remove the braking force in the event that the estimated instantaneous linear speed of the single axle falls below the vehicle’s reference linear speed, but limiting the removal of the braking force to a period not exceeding 10 seconds.

[022] Furthermore, in §4.2.4.3.2 “Functional characteristics”, it is recommended that the electrical / electronic circuits of the wheel rotation monitoring device be independent of the electrical / electronic circuits of the anti-skid device.

[023] Recommendation §4.2.4.3.3 implies the possibility that the wheel speed monitoring device may act on an electropneumatic valve, referred to as a discharge solenoid valve, which causes the discharge of the brake cylinder associated with the axle that has been verified as being subject to estimated linear speed loss below the vehicle's reference linear speed.

[024] Recommendation §4.2.4.3.2 prevents the wheel rotation monitoring device from acting electrically on one of the solenoids belonging to the anti-skid valve modules, as this would involve sharing parts of the electrical circuit.

[025] The state of the art provides that the discharge solenoid valve, if activated by both the anti-slip device and the wheel rotation monitoring device, is provided with two Petition 870230021695, dated 03 / 14 / 2023, page 13 / 31 6 / 14 independent solenoids, in particular a first solenoid assigned to the anti-slip device and a second solenoid assigned to the wheel rotation monitoring device.

[026] Document EP 1577185 describes an integrated system consisting of a WSP anti-slip device and a wheel rotation monitoring device, also known as an anti-lock device. In particular, Figure 2 of EP 1577185, shown as Figure 3 in the present patent application, illustrates an anti-slip valve with electropneumatic pilot valves (12, 13), made redundant by electropneumatic pilot valves (14, 15), respectively. The electropneumatic pilot valves (12, 13) are controlled by the anti-slip device and the electropneumatic pilot valves (14, 15) are controlled by the anti-lock device if a failure of the anti-slip device has been identified, or the estimated instantaneous linear speed of the single shaft associated with said electropneumatic valves (14, 15) falls below the vehicle reference linear speed, as recommended in EN15595 §4.2.4.3.

[027] Recent developments in railway braking systems have led to considerable integration and simplification of railway braking systems, such that the electropneumatic components for controlling braking pressure and the electropneumatic components for controlling the anti-skid function coincide. Examples are patent EP 3148853 and patent EP 2830918.

[028] In Figure 1 of EP 3148853, shown as Figure 4 in the present patent application, the electropneumatic valve (10) operates, as described in EP 3148853, as a pilot to fill a pilot chamber of the relay valve (RV) controlled by the braking control unit BCU both in the braking control phase and in the anti-skid phase. In addition, the electropneumatic valve (12) acts as a pilot to empty the chamber Petition 870230021695, dated 03 / 14 / 2023, page 14 / 31 7 / 14 pilot relay valve (RV) controlled by the braking control unit BCU during both the braking control phase and the anti-slip phase. Complex interlock logic controls the software-based braking control and anti-slip control functions, both accessing the same electropneumatic valves to implement their respective functions. Furthermore, it is state-of-the-art that, in most applications, a railway braking system is provided with a function defined as remote release. This Remote Release function is necessary to remedy instances of undesirable residual pressure present in the brake cylinders associated with said braking system. Said residual pressure may be maintained in the brake cylinders due to an unexpected failure of one or more components constituting said braking system.High residual pressure can cause wheel lock-up, resulting in serious damage to the wheels at the point of contact with the rail. Residual pressure that does not cause wheel lock-up results in continuous unwanted braking due to dangerous overheating of the braking friction elements, posing a risk of fire, particularly serious in underground trains inside tunnels without escape routes for passengers. The Remote Release function is normally implemented by means of an electro-pneumatic valve inserted into the braking system in a position on the pneumatic diagram where, in the rest state or de-energized, it does not interfere with the normal functions of said braking system.When the train driver, or any automatic train control system, such as the Train Control Monitoring System (TCMS), decides to release the brake due to residual pressure detected in the brake cylinders, they perform an action that leads to the excitation of the electro-pneumatic remote release valve. In the excited condition, the remote release valve... Petition 870230021695, dated 03 / 14 / 2023, page 15 / 31 8 / 14 electropneumatics must perform two fundamental actions: - to prevent the flow of compressed air to the associated brake cylinders, also preventing the compressed air source from being able to release additional air in other directions, such as at atmospheric pressure; and - to cause the associated brake cylinders to discharge into atmospheric pressure.

[029] In Figure 1 of EP 2830918, shown as Figure 6 in the present patent application, the electropneumatic valves “Shaft 1 Maintain MV” and “Shaft 2 Maintain MV” operate as filling pilots for the respective associated brake cylinders (BCP1, BCP2) acting on the pneumatic valves (6, 7) and (16, 17), respectively. In addition, the electropneumatic valves “Shaft 1 Vent MV” and “Shaft 2 Vent MV” operate as venting pilots for the respective associated brake cylinders (BCP1, BCP2) acting on the pneumatic valves (6, 7) and (16, 17), respectively. Also in this case, the electropneumatic valves are used by the integrated control electronics simultaneously for brake pressure control and anti-skid control functions.

[030] Both devices described can find applications in braking systems for rail vehicles / trains operating at speeds above 200 km / h. However, the introduction of additional electropneumatic components to meet EN15595 §4.2.4.3 “Special characteristics of WSP systems for high speeds (v > 200 km / h)” and subchapters, compromises the levels of simplicity and integration achieved by such devices.

[031] Document WO 2019 / 053599 A1 describes a control system for emergency service and braking, however, the above problems still remain unsolved. Petition 870230021695, dated 03 / 14 / 2023, page 16 / 31 9 / 14 Description of the Invention

[032] One objective of the present invention is to provide a solution that is capable of meeting the EN15595 §4.2.4.3 standard “Special characteristics of WSP systems for high speeds (v > 200km / h)” and subchapters, without compromising the simplicity and integration levels of the solution.

[033] The present invention is applicable to conventional systems.

[034] In summary, the present invention therefore describes the use of an electropneumatic valve having a Remote Release function, present in a braking system, as an actuator to be assigned to a wheel rotation monitoring device to comply with the recommendations reported in EN15595 §4.2.4.3.2 and §4.2.4.3.3.

[035] The aforementioned objectives and advantages and others are achieved, according to one embodiment of the invention, by a rotation monitoring system of at least one axle for a railway vehicle or train having the characteristics defined in claim 1. Preferred embodiments of the invention are those defined in the dependent claims, the content of which should be understood as an integral part of the present description. Brief Description of the Drawings

[036] The functional and structural characteristics of some preferred embodiments of a rotation monitoring system for at least one axle for a railway vehicle or train, according to the invention, will now be described. Reference will be made to the accompanying drawings, in which: Figure 1 shows a complete anti-slip system according to the state of the art; Figure 2 shows a detail of a valve unit. Petition 870230021695, dated 03 / 14 / 2023, page 17 / 31 10 / 14 anti-slip and the control circuits of an anti-slip device; Figure 3 shows a well-known anti-slip valve assembly supplied with redundant pilot valves; Figure 4 shows a well-known integrated railway braking system; Figure 5 shows one embodiment of the present invention; and Figure 6 shows a well-known integrated railway braking system. Description of Embodiments of the Invention

[037] Before explaining a plurality of embodiments of the invention in detail, it should be noted that the invention is not limited in its embodiment to the construction details and the embodiment of the components presented in the following description or shown in the drawings. The invention may take other embodiments and be implemented or practically realized in different ways. It should also be understood that the phraseology and terminology are for descriptive purposes and should not be interpreted as limiting. The use of “include” and “comprise” and their variations is intended to include the elements mentioned below and their equivalents, as well as additional elements and equivalents thereof.

[038] With reference to Figure 4, an integrated railway braking system includes an electropneumatic valve (20) for remote release, as explained above in detail, piloted by the RR electrical signal coming from outside.

[039] This electropneumatic valve (20), when de-energized, constitutes a direct pneumatic passage between an electropneumatic filling valve (10) and a pilot chamber of a relay valve (RV), in fact not interfering with the functionality of said filling valve. Petition 870230021695, dated 03 / 14 / 2023, p. 18 / 31 11 / 14 electropneumatics (10).

[040] Furthermore, the electropneumatic valve (20), when de-energized, does not interfere with an electropneumatic discharge valve (12). When the valve (20) is energized, as a consequence of an external command, said valve (20) blocks the airflow from an outlet port of the electropneumatic filling valve (10), regardless of the energized / de-energized condition of said electropneumatic filling valve (10), and connects the pilot chamber of the relay valve (RV) to the atmosphere, regardless of the energized / de-energized condition of the electropneumatic discharge valve (12).

[041] Based on the above, advantageously, the remote release electropneumatic valve (20), if used as an actuator assigned to a wheel rotation monitoring device, can fulfill the recommendations set out in EN15595 §4.2.4.3.2 and §4.2.4.3.3.

[042] In the present invention, the physical separation of the air discharge function between the electropneumatic valve (20) and the electropneumatic valve (12) constitutes an additional advantage by providing total physical as well as functional redundancy between the anti-skid device and the wheel rotation monitoring device.

[043] A similar analysis performed on the diagram in Figure 3 leads to the same conclusions.

[044] Therefore, in one embodiment of the invention, a wheel rotation monitoring system with at least one axis for a railway vehicle or train is arranged to identify at least one axis controlled by it having an estimated instantaneous linear speed lower than a predetermined instantaneous linear limit speed. The wheel rotation monitoring system with at least one axis for a railway vehicle Petition 870230021695, dated 03 / 14 / 2023, page 19 / 31 12 / 14 railway or train is also arranged to remove the braking force for one or more wheels of the axle identified as having an estimated instantaneous linear speed lower than the aforementioned predetermined instantaneous linear limit speed, by canceling a pressure to the brake cylinders associated with said at least one axle identified as having an estimated instantaneous linear speed lower than the aforementioned predetermined instantaneous linear limit speed.

[045] The cancellation of pressure for the brake cylinders associated with said at least one axle identified as having an estimated instantaneous linear speed lower than said predetermined instantaneous linear limit speed is achieved by acting on an electropneumatic valve (RR) arranged to perform a Remote Release function associated with the pneumatic circuits generating brake pressure for said brake cylinders and adapted to cancel residual braking pressure.

[046] A possible, but not exclusive, integration solution between the wheel rotation monitoring device and the valve that performs the Remote Release function is now described.

[047] With reference to Figure 5, the wheel rotation monitoring device (501), for example consisting of a microprocessor system, generates a signal (502) that assumes the logic level “1” when the wheel rotation monitoring device (501) intends to energize the solenoid valve (RR) that performs the Remote Release function, powering the solenoid (503) of the same. The signal (502) activates a monostable circuit (507) whose output (508) assumes the logic level “1” for a maximum time (T) after a 0 ^ 1 transition by the aforementioned signal (502) at its input (509). The output (508) again assumes the logic value “0” after the time (T) expires or if the signal (502) again assumes the logic level “0”, causing a reset of the Petition 870230021695, dated 03 / 14 / 2023, page 20 / 31 13 / 14 monostable (507) via its “R” input (510). The AND gate (511) conditions the signal (502) with the signal (508) and activates a controller (504) adapted to possibly translate the voltage level to power the solenoid (505) of a relay, whose contact (506) powers the solenoid (503) with the voltage (Vrr), directly or through a dedicated power supply. The monostable circuit assembly (507) and the AND gate (511) limits the consecutive energization of the electropneumatic remote release valve to a maximum time (T).

[048] Contact (512) placed in parallel with contact (506) is available to the controller or TCMS system to operate the solenoid (503) of the electropneumatic valve performing the Remote Release function, in the usual way.

[049] The relay consisting of the solenoid (505) and the contact (506) can be replaced by an opto-isolated switching element, for example, but not exclusively, by an opto-MOS, or by a functionally equivalent electronic circuit.

[050] If the software of the wheel rotation monitoring device (501) is developed at a safety level SIL > 3 according to EN50128 standards, then the expiration time function (507, 511) can be implemented directly in the software code of said wheel rotation monitoring device (501).

[051] In other words, the electropneumatic valve (RR) arranged to perform a Remote Release function can be conditioned by a hardware expiration time circuit (507, 511), or by a software expiration time function, arranged to limit an excitation command of a solenoid (503) associated with said electropneumatic valve (RR) for a predetermined continuous time (T).

[052] The software expiration time function can be Petition 870230021695, dated 03 / 14 / 2023, pp. 21-31 14 / 14 performed directly within a rotation monitoring system software for at least one axis.

[053] The predetermined continuous time (T) can take a value of 10 seconds. In fact, by setting T = 10s, the recommendation reported in EN15595 §4.2.4.3.3 is satisfied.

[054] In a further embodiment, the predetermined instantaneous linear limit speed is a function of a linear reference speed of the vehicle.

[055] Several embodiments of a method for implementing a rotation monitoring system for at least one axle for a railway vehicle or train according to the invention have been described. It is understood that each embodiment can be combined with any other embodiment. The invention, moreover, is not limited to the embodiments described, but can be varied within the scope defined by the appended claims. Petition 870230021695, dated 03 / 14 / 2023, pp. 22 / 31

Claims

1 / 2 Claims 1. A rotation monitoring system for at least one axle (501) for a rail vehicle or train, the rotation monitoring system for at least one axle (501) being arranged to: - identify at least one axle controlled by it having an estimated instantaneous linear speed lower than a predetermined instantaneous linear speed; - remove a braking force for one or more wheels of the axle identified as having an estimated instantaneous linear speed lower than the predetermined instantaneous linear speed limit,by canceling pressure on the brake cylinders associated with at least one shaft identified as having an estimated instantaneous linear speed lower than the predetermined instantaneous linear speed limit; and the rotation monitoring system of at least one shaft (501) being characterized in that the cancellation of pressure on the brake cylinders associated with at least one shaft identified as having an estimated instantaneous linear speed lower than the predetermined instantaneous linear speed limit is achieved by actuating an electropneumatic valve (20) arranged to perform a Remote Release function associated with the pneumatic circuits that generate brake pressure for the brake cylinders and adapted to cancel residual braking pressure,wherein the electropneumatic valve (20) arranged to perform a Remote Release function is conditioned by a hardware expiration time circuit (507, 511), or by a software expiration time function, arranged to limit an excitation command of a solenoid (503) associated with the electropneumatic valve (20) for a predetermined continuous time (T).

2. Rotation monitoring system of at least one axis (501), according to claim 1, characterized in that the predetermined continuous time (T) assumes a value equal to or greater than 10 seconds.

3. Rotation monitoring system with at least one axis (501) according to claim 1 or 2, characterized in that the software expiration time function is performed directly within the software of the rotation monitoring system with at least one axis (501).

4. Rotation monitoring system of at least one axis (501) according to any of the preceding claims, characterized in that the predetermined instantaneous linear limit speed is a function of a reference linear speed of the vehicle. Petition 870250057040, dated 04 / 07 / 2025, page 8 / 30

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