Safety friction clutch

Abstract

The utility model relates to the field of railway automation and telemechanics, in particular to electric point drives. The essence of the utility model is that a safety friction clutch comprises a hub in the form of a flange with a ring and a stepped cylindrical part with a threaded section, on which movable and fixed friction disks are mounted, pressed by a clamping device including a pressure disk, helical springs, a pressure housing, a pressure nut and a locking element with a pressure flange. The clutch further comprises a housing with a toothed rim and a bearing, wherein the housing, pressure flange, pressure disk and pressure housing are made of an aluminum alloy. The technical result consists in increasing the corrosion resistance of the clutch during operation under conditions of exposure to atmospheric precipitation, moisture and chemically aggressive environments of the railway infrastructure. 1 c.p. fils, 2 figs.

Description

[0001] Field of technology of the utility model

[0002] The utility model relates to the field of railway automation and telemechanics, in particular to electric switch drives, and is designed to prevent failure of the electric motor during overload, the electric drive during the process of switching switches, and limiting the forces of the switch switches on the frame rails of switch switches.

[0003] Prior art of the utility model

[0004] Electric point machines are essential components of railway automation and telemetry systems, ensuring the operation of switch blades and monitoring their extreme positions. The key component of a point machine is the friction clutch, designed to limit the force exerted on the switch blades and their impact on the stock rails, as well as to prevent motor failure due to overload. During operation, the friction clutches of point machine systems are continuously exposed to precipitation, moisture, and the chemically aggressive environments of railway infrastructure, placing increased demands on the corrosion resistance of their structural components.The designs of safety friction clutches currently in use are made primarily from steel materials, which have significant drawbacks in terms of corrosion resistance during long-term operation under the specified conditions.

[0005] The safety friction clutch known from the document [RU205758U1, publication date: 06.08.2021] was selected as a prototype. The known clutch comprises a hub made in the form of a flange having a ring and a stepped cylindrical part with a threaded section at the end of the cylinder. Movable and fixed friction discs are mounted on the cylindrical part of a larger diameter adjacent to the flange ring. The friction discs are pressed against the inner surface of the flange ring by a clamping device mounted on the cylindrical part of the hub of a smaller diameter and consisting of a pressure disc, helical springs, a pressure housing, a pressure nut, and a locking element with a pressure flange.

[0006] The disadvantage of the prototype is the low corrosion resistance of the coupling, which in turn leads to a number of significant shortcomings, including:

[0007] High failure rate of coupling components, as the use of steel materials for their manufacture entails high susceptibility to the corrosive effects of precipitation, moisture, and chemically aggressive environments typical of railway infrastructure. Corrosive failure of housing components leads to distortion of their geometry, reduced mechanical strength, and, consequently, a reduction in the service life of the coupling as a whole;

[0008] Unstable friction disc clamping force, as corrosion of the steel components of the clamping device alters their geometric parameters and disrupts the interaction of the mating surfaces. This leads to a deviation in the actual clamping force from the calculated value and, consequently, to instability in the clutch actuation torque during operation;

[0009] Low reliability of the clamping nut locking, as corrosion of the steel locking element hinders its interaction with the clamping nut. This creates a risk of spontaneous change in the clamping nut position under vibration loads, resulting in a loss of the specified clamping force of the friction discs.

[0010] Thus, the technical problem that the utility model is aimed at solving is the need to eliminate the existing shortcomings of the prototype.

[0011] Disclosure of the essence of the utility model

[0012] The technical result that the utility model is aimed at achieving is to increase the corrosion resistance of the coupling during operation under conditions of exposure to atmospheric precipitation, moisture and chemically aggressive environments of the railway infrastructure.

[0013] The essence of the utility model is as follows.

[0014] A safety friction clutch comprises a hub formed in the form of a flange having a ring and a stepped cylindrical portion with a threaded section at the end of the cylinder. Movable and fixed friction discs are mounted on the cylindrical portion of the larger diameter adjacent to the flange ring. The friction discs are pressed against the inner surface of the flange ring by a clamping device mounted on the cylindrical portion of the hub of a smaller diameter and consisting of a pressure disc, springs, a pressure housing, a pressure nut, and a locking element with a pressure flange. Unlike the prototype, the clutch comprises a housing with a gear ring with a bearing. The said housing, pressure flange, pressure disc, and pressure housing are made of an aluminum alloy.

[0015] The flange-type hub ensures torque transmission between the friction discs and the kinematic chain of the switch drive. The flange-type hub ensures proper interaction of all its components, including those made of corrosion-resistant materials, thereby increasing the coupling's corrosion resistance during operation under conditions of precipitation, moisture, and the chemically aggressive environments of railway infrastructure. The hub can be made of structural or alloy steel.

[0016] The ring and stepped cylindrical section with a threaded section at the end of the cylinder accommodate the friction discs and clamping device, and also allow for adjustment of the friction disc clamping force by sliding the clamping nut along the threaded section. The stepped design of the cylindrical section ensures precise positioning of the aluminum alloy clamping device components, preventing their mutual displacement and maintaining the unit's stability in aggressive environments. This enhances the coupling's corrosion resistance during operation in conditions exposed to precipitation, moisture, and the chemically aggressive environments of railway infrastructure. The ring and stepped cylindrical section can be made of structural or alloy steel.

[0017] Friction discs transmit torque from the coupling housing to the hub through frictional forces generated by their mutual compression, and limit the transmitted torque under overload conditions through mutual slippage. The placement of the friction discs within an aluminum alloy housing protects them from direct exposure to precipitation, moisture, and chemically aggressive environments, maintaining a stable friction coefficient during operation. This enhances the coupling's corrosion resistance during operation in conditions exposed to precipitation, moisture, and chemically aggressive environments found in railway infrastructure.

[0018] The installation of sliding and fixed friction discs on a larger-diameter cylindrical section adjacent to the flange ring ensures their correct positioning relative to the inner surface of the flange ring, creating a friction unit with specified torque transmission characteristics. The placement of the friction discs on the larger-diameter cylindrical section ensures their protected placement within an aluminum alloy housing, eliminating direct exposure of the friction unit to aggressive environments, thereby increasing the coupling's corrosion resistance during operation in conditions exposed to precipitation, moisture, and the chemically aggressive environments of railway infrastructure. Fixed discs can be made of structural steel, while the sliding discs can be made of cermet materials.

[0019] The clamping device presses the friction discs against the inner surface of the flange ring to create and maintain the required clamping force, which determines the friction torque between the moving and fixed friction discs. Stable clamping of the friction discs against the inner surface of the flange ring is also ensured by maintaining the geometric parameters of the clamping device components, which are made of corrosion-resistant aluminum alloy. This eliminates any deviation in the actual clamping force from the calculated value, thereby increasing the coupling's corrosion resistance during operation under conditions of precipitation, moisture, and the chemically aggressive environments of railway infrastructure.

[0020] The clamping device adjusts and maintains the specified clamping force on the friction discs, which determines the clutch actuation point during operation of the electric point machine. The main components of the clamping device, made of aluminum alloy, maintain their geometric parameters even in aggressive environments, ensuring stable clamping force throughout the entire service life of the clutch. This increases the clutch's corrosion resistance during operation in conditions exposed to precipitation, moisture, and the chemically aggressive environments of railway infrastructure.

[0021] Mounting the clamping device on the smaller-diameter cylindrical portion of the hub ensures its precise positioning and axial fixation relative to the hub, preventing displacement of the clamping device components during operation. Mounting the clamping device on the smaller-diameter cylindrical portion ensures proper interaction between the pressure plate, pressure housing, and pressure flange, all made of aluminum alloy. This ensures their functional characteristics are maintained in aggressive environments, thereby increasing the coupling's corrosion resistance during operation in conditions exposed to precipitation, moisture, and the chemically aggressive environments of railway infrastructure.

[0022] The pressure plate, coil springs, pressure housing, pressure nut, and locking element with pressure flange collectively transmit, evenly distribute, and lock the friction disc clamping force. The aluminum alloy construction of the pressure plate, pressure housing, and pressure flange ensures corrosion resistance, maintaining the geometric parameters of the mating surfaces and the stability of the transmitted clamping force throughout the entire service life of the coupling. This enhances the coupling's corrosion resistance during operation in conditions exposed to precipitation, moisture, and the chemically aggressive environments found in railway infrastructure. The pressure nut can be made of structural or alloy steel, and the coil springs can be made of spring steel.

[0023] The housing with the ring gear and bearing receives and transmits torque from the gear wheel of the point motor to the friction discs, as well as supports the radial and axial loads that arise during clutch operation. The housing, made of aluminum alloy, forms a protective shell for the internal components of the clutch, resistant to precipitation, moisture, and chemically aggressive environments. This prevents corrosion of both the housing itself and the components it protects, thereby increasing the coupling's corrosion resistance during operation in conditions exposed to precipitation, moisture, and the chemically aggressive environments of railway infrastructure. The ring gear and housing can be made of aluminum alloy, and the bearing can be implemented as a ball or roller bearing.

[0024] The housing, pressure flange, pressure plate, and pressure housing are made of aluminum alloy, ensuring high corrosion resistance for these components under the conditions of switch machine operation. The aluminum alloy forms a natural oxide layer on the surface of these components, preventing further corrosion when exposed to precipitation, moisture, and chemically aggressive environments. This maintains the geometric parameters and mechanical properties of the components throughout the entire service life of the coupling, thereby increasing the coupling's corrosion resistance during operation under the influence of precipitation, moisture, and chemically aggressive environments found in railway infrastructure.

[0025] The clamping device's locking element can be implemented as a spring-loaded eccentric latch pivotally mounted in the clamping flange. The clamping nut is provided with grooves designed to accommodate the aforementioned latch during locking. This ensures reliable fixation of the clamping nut in a predetermined position, preventing its spontaneous loosening under the influence of vibration loads during operation of the point motor. The eccentric latch is pivotally mounted in the clamping flange, made of aluminum alloy, and interacts with the grooves of the clamping nut, ensuring locking without the use of additional fasteners made of materials susceptible to corrosion.The secure clamping nut ensures consistent clamping force on the friction discs during long-term operation in aggressive environments, thereby increasing the coupling's corrosion resistance during operation in atmospheric precipitation, moisture, and the chemically aggressive environments found in railway infrastructure. The eccentric latch can be made of stainless or alloy steel.

[0026] The utility model is characterized by a previously unknown set of essential features from the prior art, distinguished in that the coupling contains a housing with a gear ring with a bearing, wherein the housing, pressure flange, pressure disk and pressure housing are made of an aluminum alloy:

[0027] The housing with a gear ring and bearing ensures the transmission of torque from the gearbox of the switch electric drive to the friction discs and the perception of the resulting radial and axial loads, and its execution from an aluminum alloy forms a protective shell for the internal elements of the coupling, resistant to the effects of precipitation, moisture and chemically aggressive environments of the railway infrastructure;

[0028] The production of the housing, pressure flange, pressure disk and pressure housing from aluminum alloy ensures the formation of a natural oxide layer on the surface of these parts, which prevents the corrosion destruction of the material, which maintains the geometric parameters and mechanical properties of the parts throughout the entire service life of the coupling.

[0029] The combination of essential features of this utility model ensures protection of the clutch's internal components via a corrosion-resistant housing and maintains the geometric parameters of the clamping device components through the use of an aluminum alloy. The combination of the aluminum alloy housing acting as a protective shell, while the pressure flange, pressure plate, and pressure housing, also made of aluminum alloy, maintain stable friction disc clamping force under prolonged exposure to aggressive environments, results in increased coupling corrosion resistance during operation in conditions of precipitation, moisture, and chemically aggressive environments found in railway infrastructure.

[0030] The utility model has a set of essential features previously unknown in the prior art, which indicates its compliance with the patentability criterion of “novelty”.

[0031] Implementation of a utility model

[0032] The utility model is explained by the following materials.

[0033] Fig. 1 - Safety friction clutch, side view, longitudinal section.

[0034] Fig. 2 - Safety friction clutch, isometric view, longitudinal segmental section.

[0035] To illustrate the possibility of implementation and a more complete understanding of the essence of the utility model, a particular case of its implementation is presented below, which can be changed or supplemented in any way, while the present utility model is in no way limited to the particular case presented.

[0036] The safety friction clutch comprises a housing 1 with a toothed ring 2 with a bearing 3, a hub 4 made in the form of a flange having a ring 5 and a stepped cylindrical part with a threaded section at the end of the cylinder, while on the cylindrical part of a larger diameter adjacent to the flange ring, steel fixed and metal-ceramic movable disks 6 and 7 are installed, respectively, located inside the housing 1. Friction disks 6 and 7 are pressed against the inner surface of the flange ring by a clamping device mounted on the cylindrical part of the hub of a smaller diameter, including a pressure disk 8, a pressure housing 9 with holes, helical springs 10 installed between the pressure disk 8 and the pressure housing 9, a clamping nut 11. The locking element is made in the form of a pressure flange 12 with an eccentric latch 13, pivotally mounted in pressure flange 12 and spring-loaded by means of plate springs 14.The clamping nut 11 has grooves designed to accommodate the eccentric latch 13 during locking. Steel disks 6 are connected to the housing 1, and metal-ceramic disks 7 to the hub 4. Housing 1, pressure flange 12, pressure disk 8, and pressure housing 9 are made of aluminum alloy.

[0037] The utility model works as follows.

[0038] Before operation, a certain pressing force is set for the friction discs 6 and 7 against each other and against the flange of the hub 4 using the clamping nut 11 through the pressure flange 12, the pressure housing 9, the coil springs 10 and the pressure disc 8. This force provides a certain friction moment between the friction discs 6 and 7, to create a force from the electric drive, which is necessary to move the switches and limit their impact on the frame rails.

[0039] To prevent the clamping nut 11 from loosening, it is locked by a latch 13 pivotally mounted in the pressure flange 12 and spring-loaded by leaf springs 14. Grooves are provided in the clamping nut 11 for locating the latch 13 in one of them during locking. When the latch 13 is removed from the groove, the clamping nut 11 is able to rotate and move along the thread of the hub 4. The grooves in the clamping nut 11 can be used during its rotation with a round-head nut wrench.

[0040] During the switch translation process, rotation from the electric motor is transmitted through the gear reducer to ring gear 2 and then through housing 1, friction discs 6 and 7, hub 4, and then to the mechanism that converts rotation into linear motion of the actuator. Rotation is transmitted without friction discs 6 and 7 slipping relative to each other. If a hard foreign object gets between the switch and the stock rail, translation becomes impossible. In this case, the switches stop before reaching their extreme positions, and the control signal to shut off is not sent to the electric motor, which continues to operate. When the blades stop, the hub 4 and friction discs 7 stop. Under the influence of the torque of the electric motor, the toothed ring 2, housing 1 and friction discs 6 continue to rotate, overcoming the friction moment between them and the friction discs 7.This allows the electric motor to continue rotating, preventing it from failing. Furthermore, by limiting the torque transmitted from the electric motor, the force exerted by the switch blade on the stock rail is limited. The friction clutch also limits the inertial force of the switch blade on the stock rail when they meet at the end of the switch.

[0041] This ensures the achievement of a technical result consisting of increasing the corrosion resistance of the coupling during operation under conditions of exposure to precipitation, moisture and chemically aggressive environments of the railway infrastructure.

Claims

1. A safety friction clutch comprising a hub made in the form of a flange having a ring and a stepped cylindrical part with a threaded section at the end of the cylinder, wherein on the cylindrical part of a larger diameter adjacent to the flange ring, movable and fixed friction disks are mounted, wherein the friction disks are pressed against the inner surface of the flange ring by a clamping device mounted on the cylindrical part of the hub of a smaller diameter and consisting of a pressure disk, springs, a pressure housing, a pressure nut and a locking element with a pressure flange, characterized in that it comprises a housing with a toothed rim with a bearing, wherein said housing, pressure flange, pressure disk and pressure housing are made of an aluminum alloy.

2. The coupling according to paragraph 1, characterized in that the locking element of the clamping device is made in the form of a spring-loaded eccentric latch, pivotally mounted in the pressure flange, and grooves are made on the clamping nut, intended for placing the aforementioned latch in them during locking.

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