Memory alloy anti-loosening gasket for railway traction power supply equipment

Abstract

The utility model belongs to railway traction power supply equipment fastening technical field, concretely relates to a railway traction power supply equipment memory alloy lock washer, based on the butterfly shape multistage lock intelligent washer of shape memory alloy and its application in railway traction power supply system bolt connection. Still include lock washer, lock washer includes washer through -hole, annular gasket and connecting gasket, connecting gasket is memory alloy material, annular gasket is set up washer through -hole and is hollow annular, annular gasket is equipped with a plurality, be equipped with deformation indicating board on the washer, deformation indicating board is memory alloy material, deformation indicating board is flat plate state under -40 ~ 40 DEG C, deformation indicating board is curved plate state under 50 ~ 60 DEG C. Through memory alloy high temperature deformation realizes compression and self -adaptation load regulation. Through deformation indicating board 8 can check whether the loosening condition of bolt 3 occurs quickly, can carry out pertinence check maintenance.

Description

Technical Field

[0001] This utility model belongs to the field of fastening technology for railway traction power supply equipment, specifically relating to a shape memory alloy anti-loosening gasket for railway traction power supply equipment, a butterfly-shaped multi-step anti-loosening smart gasket based on shape memory alloy (SMA) and its application in bolt connections of railway traction power supply systems. This technology is particularly designed to address the bolt anti-loosening requirements of high-speed railway traction power supply equipment in high-vibration, large-temperature-difference, and corrosive environments. Through innovative material formulation and structural design, it solves the technical problem of traditional anti-loosening gaskets easily failing under harsh working conditions. Background Technology

[0002] The main reason for overheating at external connectors of power supply equipment is poor contact. An inability to maintain a secure connection leads to increased resistance at the connector, resulting in localized overheating during operation. According to Joule's law, Q=I... 2 Rt(J). In the formula, Q is the heat generated by the current passing through the conductor (J); I is the current passing through the conductor (A); R is the resistance of the conductor (Ω); and t is time (S). When the connection is poor, the contact resistance increases, which in turn increases the heat generated by the current passing through the conductor, causing a temperature rise.

[0003] The existing technology for guide wire clamp bolts in railway traction power supply equipment faces three major technical challenges: 1. Mechanical loosening caused by high frequency vibration: Under a 50Hz vibration environment, the elasticity decay rate of traditional spring washers (such as GB / T 93) reaches 30% / year, resulting in a continuous decrease in contact pressure.

[0004] 2. Thermal stress caused by temperature fluctuations: The temperature difference between day and night can reach more than 40°C, causing the bolted connection to undergo periodic thermal expansion and contraction, which traditional gaskets cannot dynamically compensate for.

[0005] 3. Performance degradation under corrosive environments: In salt spray environments (Cl⁻ concentration > 0.3 mg / m³), the corrosion rate of carbon steel gaskets reaches 0.2 mm / year, and stainless steel gaskets still have the risk of stress corrosion cracking.

[0006] Existing solutions suffer from the following shortcomings and industry technical bottlenecks: static anti-loosening structures (such as double nuts and locking washers) cannot adapt to dynamic load changes, and the maintenance cycle is short (usually requiring re-tightening every 3-6 months). Limitations of traditional materials: 1. Carbon steel gaskets have an upper operating temperature limit of 180℃, and their elastic modulus decreases by 40% at high temperatures. 2. While 316L stainless steel gaskets are corrosion-resistant, they are expensive and lack sufficient resistance to vibration relaxation. Limited functionality: Existing shape memory alloy gaskets are mostly planar structures (e.g., US20180128374A1), with a friction coefficient of only 0.15-0.25, resulting in insufficient anti-slip performance. Utility Model Content

[0007] This invention addresses the shortcomings of existing technologies by providing a shape memory alloy anti-loosening gasket for railway traction power supply equipment that features anti-loosening, anti-detachment, and load adaptive adjustment.

[0008] A shape memory alloy anti-loosening washer for railway traction power supply equipment includes a nut, a washer, and a bolt. The bolt passes through a cable clamp or a power conductive plate. The washer is fitted onto the bolt and fits against the cable clamp or power conductive plate. The nut and bolt press the washer firmly onto the cable clamp or power conductive plate. The cable clamp holds the power cable. The washer also includes an anti-loosening washer, comprising a washer through-hole, an annular washer, and a connecting washer. The connecting washer is made of shape memory alloy. The annular washer has a washer through-hole and is hollow. Multiple annular washers are provided, nested with gaps between them. Adjacent annular washers are connected by the connecting washer. The connecting washer is flat at -40 to 40°C and curved at 50 to 60°C. The bending of the connecting washer causes the annular washer to rise sequentially outward from the center of the washer through-hole. The curved connecting washer and the annular washer together form a C-shape. The gasket is equipped with a deformation indicator plate, which is made of shape memory alloy material. The deformation indicator plate is flat at -40 to -40℃ and curved at 50 to -60℃.

[0009] The multiple annular pads are concentrically fitted along the center of the gasket through hole, and the diameters of the multiple annular pads are different.

[0010] It also includes a support pad, which is located below the annular pad. The support pad is connected to the innermost annular pad with the smallest diameter. The support pad is in contact with other annular pads but not connected. The support pad is flat at -40-60℃ and curved at 70-80℃. The curved support pad is C-shaped. The bending direction of the support pad is opposite to that of the annular pad. The curved support pad and the annular pad together form an X-shape.

[0011] Furthermore, the connecting pad is connected to the middle of the annular pad.

[0012] Furthermore, the annular pad is provided in at least 3 sets.

[0013] Furthermore, the diameter of the support pad is greater than or equal to that of the annular pad.

[0014] Furthermore, the gasket has a folded edge, which is bent to fit against the nut and the anti-loosening gasket.

[0015] Furthermore, the gaskets are connected by a deformation indicator plate.

[0016] The technical effectiveness has been verified through laboratory and field tests: 1. Anti-loosening performance: Vibration test (GB / T 10431): After 1000 cycles at 50Hz / 0.5mm amplitude, the preload retention rate is >95% (conventional gaskets <70%); Under salt spray environment (GB / T 10125), the anti-slip performance decays by <5% after 2000 hours.

[0017] 2. Electrical performance: Reduces the contact resistance of the connector by ≥10% (measured from 35μΩ to 31μΩ for M12 connector); reduces the temperature rise by 18% (from 65℃ to 53℃ under the same operating conditions).

[0018] 3. Economic benefits: Extends the maintenance cycle by more than 3 times (from 3 months to 12 months); energy saving rate of 12.5% ​​(actual measurement shows that a certain traction substation saves 32,000 kWh of electricity per year). Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present utility model. Figure I ; Figure 2 This is a schematic diagram of the structure of the present utility model. Figure II ; Figure 3 This is a schematic diagram of a ring-shaped pad structure; Figure 4 This is a schematic diagram of the combined structure of the annular pad and the supporting pad; Figure 5 A schematic diagram of a structure where the outer diameter of the support pad is larger than that of the annular pad. Figure 6 for Figure 3 Schematic diagram of the bending state of a shape memory alloy under one deformation. Figure 7 for Figure 4 Schematic diagram of the bending state of shape memory alloy under secondary deformation; Figure 8 for Figure 5 Schematic diagram of the bending state of shape memory alloy under secondary deformation; Figure 9 This is a schematic diagram showing the clamping state of the power cable; Figure 10 This is a schematic diagram showing the clamping state of the electrical conductive plate. Figure 11 This is a schematic diagram of a railway cable connector connection. Figure 12 Schematic diagram of the gasket assembly connecting the deformation indicator plate; Figure 13 for Figure 12 Schematic diagram of deformation indicator plate showing bulging deformation alarm; Figure 14 for Figure 12 Top view; Figure 15A separate schematic diagram is provided for the deformation indicator plate; Figure 16 for Figure 15 Schematic diagram of deformation indicator plate showing arched deformation alarm; The markings in the diagram are: 1. Nut; 2. Washer; 3. Bolt; 4. Power cable; 5. Cable clamp; 6. Anti-loosening washer; 7. Power conductive plate; 8. Deformation indicator plate; 9. Folded edge; 601. Washer through hole; 602. Annular washer; 603. Connecting washer; 604. Support washer. Detailed Implementation

[0020] A shape memory alloy anti-loosening washer for railway traction power supply equipment includes a nut 1, a washer 2, and a bolt 3. The bolt 3 passes through a cable clamp 5 or a conductive plate 7. The washer 2 is fitted onto the bolt 3 and fits against the cable clamp 5 or the conductive plate 7. The nut 1 and bolt 3 press the washer 2 firmly onto the cable clamp 5 or the conductive plate 7. The cable clamp 5 holds the power cable 4. The device also includes an anti-loosening washer 6, which includes a washer through hole 601, an annular washer 602, and a connecting washer 603. The connecting washer 603 is made of shape memory alloy material. The gasket 602 has a hollow annular through-hole 601. Multiple annular gaskets 602 are nested together with gaps between them. Adjacent annular gaskets 602 are connected by connecting gaskets 603. At -40 to -40℃, the connecting gasket 603 is flat; at 50 to -60℃, it is curved. The bending of the connecting gasket 603 causes the annular gaskets 602 to rise sequentially outward from the center of the through-hole 601. The curved connecting gasket 603 and the annular gasket 602 together form a C-shape. High-temperature deformation of the shape memory alloy achieves clamping and adaptive load adjustment, making it particularly suitable for bolt loosening due to vibration and temperature changes. This effectively improves the stability of the power connector. The gasket 2 has a deformation indicator plate 8 made of shape memory alloy; at -40 to -40℃, the deformation indicator plate 8 is flat; at 50 to -60℃, it is curved. Due to the compaction effect of nuts and bolts, it is not easy to see with the naked eye whether the joint is loose. However, the deformation indicator plate 8 can be used to quickly check whether the bolt 3 is loose, and targeted inspection and maintenance can be carried out.

[0021] The multiple annular pads 602 are concentrically fitted along the center of the gasket through hole 601, and the diameters of the multiple annular pads 602 are different. This achieves multi-ring contact, which can effectively increase the clamping force of the multi-point power connector and improve the stability of the power connector.

[0022] It also includes a support pad 604, located below the annular pad 602. The support pad 604 is connected to the innermost smallest diameter annular pad 602, but it is in contact with other annular pads 602 without being connected. At temperatures ranging from -40°C to 60°C, the support pad 604 is flat; at temperatures ranging from 70°C to 80°C, it is curved, forming a C-shape. The bending direction of the support pad 604 is opposite to that of the annular pad 602, and the curved support pad 604 and the annular pad 602 together form an X-shape. Multiple, multi-stage deformations ensure the ability to provide adaptive loads under different temperatures and extreme conditions.

[0023] The connecting pad 603 is connected to the middle of the annular pad 602, facilitating greater displacement and deformation allowance. At least three sets of annular pads 602 are provided, enabling multi-level height lifting and multi-point cable contact. The diameter of the supporting pad 604 is greater than or equal to that of the annular pad 602. A larger diameter for the supporting pad 604 compared to the annular pad 602 provides a more stable contact force.

[0024] The gasket 2 has a folded edge 9, which is bent to fit against the nut 1 and the anti-loosening gasket 6. This fits against the locking nut 1 to further prevent the nut from vibrating and loosening. The gaskets 2 are connected by a deformation indicator plate 8. This allows for simultaneous detection and warning of loosening of a set of joints in the connected state.

[0025] The following further clarifies this point, using specific implementation examples and shape memory alloy materials: The shape memory alloy anti-loosening gasket material is a Ni-Ti-Co shape memory alloy with the following composition range (atomic percentage): Ni 50.2-50.8%, Ti 48.5-49.3%, Co 0.1-0.4%; the phase transformation temperature (Af) is adjustable from -20℃ to 80℃, and the shape recovery rate is ≥95%. The number of annular 602 gaskets is 3-15, forming a multi-level structure, suitable for M2-M36 bolt specifications; when triggered at Af temperature, the output restoring force is 30-4000N, and the contact resistance decreases by ≥10%. The material has a yield strength ≥851MPa and an elongation ≥15%; the corrosion rate after 1000 hours of salt spray testing is <0.01mm / year; and the preload retention rate after 1000 cycles of vibration testing (50Hz / 0.5mm) is >95%.

[0026] Includes the following steps: (1) Select the aforementioned shape memory alloy gasket; (2) Apply 40-110% of the standard installation torque to flatten the shims when tightening the bolts; (3) When the temperature rises to 50-60℃ due to loosening of the joint, the gasket outputs a restoring force of 30-2000N to automatically compensate for the contact pressure. (4) When the joint loosens again, causing the temperature to rise to 70-80℃, the support plate will be bent into a plate shape to further output restoring force to automatically compensate for the contact pressure.

[0027] (5) When the temperature rises to 50-60℃ due to loosening of the joint, the deformation indicator plate can be used to quickly check whether the bolts have become loose and carry out targeted inspection and maintenance.

[0028] This invention is applicable to 100~8000A current-carrying connectors, and is especially suitable for contact wire jumper clamps and equipment clamps; it reduces the temperature rise of the connector by ≥15% and the contact resistance by ≥10%.

[0029] This invention is applicable to a railway traction power supply system. The current guide clamp and connecting bolt adopt the structure of this invention. It is suitable for an ambient temperature range of -40~+80℃. Under a rated current of 8000A, the temperature rise is ≥15℃ lower than that of the traditional system.

[0030] When the shape memory alloy gasket is installed on the clamp bolt, it remains flat under the pre-tightening of the bolt when the clamp temperature is normal. When the clamp bolt loosens due to vibration or the joint expands or contracts, the contact pressure decreases, resulting in increased contact resistance and heat generation. If the heat generation exceeds the phase transition temperature of the gasket, the gasket will tend to return to its original shape before installation, thereby outputting a larger elastic force (30-2000N), making the bolt connection tighter, increasing the contact pressure, and reducing the heat generation of the clamp.

Claims

1. A shape memory alloy anti-loosening washer for railway traction power supply equipment, comprising a nut (1), a washer (2), and a bolt (3), wherein the bolt (3) passes through a cable clamp (5) or a power conductive plate (7), the washer (2) is fitted onto the bolt (3) and fits against the cable clamp (5) or the power conductive plate (7), and the washer (2) is pressed onto the cable clamp (5) or the power conductive plate (7) by the nut (1) and the bolt (3), wherein the cable clamp (5) clamps the power cable (4); characterized in that It also includes anti-loosening gaskets (6), which include gasket through holes (601), annular gaskets (602) and connecting gaskets (603). The connecting gaskets (603) are made of shape memory alloy. The annular gaskets (602) have gasket through holes (601) and are hollow annular. Multiple annular gaskets (602) are provided and multiple annular gaskets (602) are set together with gaps. Adjacent annular gaskets (602) are connected by connecting gaskets (603). The connecting gaskets (603) are flat at -40-40℃. At 50-60℃, the connecting pad (603) is in the shape of a bent plate. The bending of the connecting pad (603) causes the annular pad (602) to rise outward along the center of the gasket through hole (601). The bent plate connecting pad (603) and the annular pad (602) together form a C-shape. The gasket (2) is provided with a deformation indicator plate (8). The deformation indicator plate (8) is made of shape memory alloy material. At -40-40℃, the deformation indicator plate (8) is in the shape of a flat plate. At 50-60℃, the deformation indicator plate (8) is in the shape of a bent plate.

2. The shape memory alloy anti-loosening gasket for railway traction power supply equipment according to claim 1, characterized in that... The plurality of annular pads (602) are concentrically fitted along the center of the gasket through hole (601), and the diameters of the plurality of annular pads (602) are different.

3. A shape memory alloy anti-loosening gasket for railway traction power supply equipment according to claim 2, characterized in that... It also includes a support pad (604), which is located below the annular pad (602). The support pad (604) is connected to the innermost smallest diameter annular pad (602). The support pad (604) is in contact with other annular pads (602) but not connected. The support pad (604) is flat at -40-60℃ and curved at 70-80℃. The curved support pad (604) is C-shaped. The bending direction of the support pad (604) is opposite to that of the annular pad (602). The curved support pad (604) and the annular pad (602) together form an X-shape.

4. A shape memory alloy anti-loosening gasket for railway traction power supply equipment according to claim 1, characterized in that... The connecting pad (603) is connected to the middle of the annular pad (602).

5. A shape memory alloy anti-loosening gasket for railway traction power supply equipment according to claim 1, characterized in that... The annular pad (602) is provided in at least 3 sets.

6. A shape memory alloy anti-loosening gasket for railway traction power supply equipment according to claim 3, characterized in that... The diameter of the support pad (604) is greater than or equal to that of the annular pad (602).

7. A shape memory alloy anti-loosening gasket for railway traction power supply equipment according to claim 1, characterized in that... The gasket (2) has a folded edge (9), which is bent to fit against the nut (1) and the anti-loosening gasket (6).

8. A shape memory alloy anti-loosening gasket for railway traction power supply equipment according to claim 1, characterized in that... The gaskets (2) are connected by a deformation indicator plate (8).

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