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CN-118110095-B - Base structure for pendulum shaft type cable saddle and forming method thereof

CN118110095BCN 118110095 BCN118110095 BCN 118110095BCN-118110095-B

Abstract

The invention discloses a base structure for a pendulum shaft type cable saddle and a forming method thereof. The base structure comprises a base body and a bearing key, wherein the base body is of a non-quenched and tempered structure and is provided with a beam which protrudes upwards and is used for supporting a cable saddle body, the bearing key is of a quenched and tempered structure and is connected to the beam of the base body, the bearing key is exposed out of a bearing surface of the base body, the top side of the bearing key is provided with an arc-shaped curved surface structure, and when the cable saddle body is located on the base structure, the bearing surface of the bearing key and the bottom of the saddle body form a relative rolling fit relationship. The invention effectively reduces the technical difficulty of the base structure forming of the swing axle type cable saddle supported by the base supporting beam while guaranteeing the forming quality, has good economy, and is beneficial to the great promotion and application of the swing axle type cable saddle supported by the base supporting beam in the suspension bridge structure.

Inventors

  • CHEN YUANLIN
  • LIU CHANGHUA
  • HUANG ANMING
  • ZHANG FAN

Assignees

  • 德阳天元重工股份有限公司

Dates

Publication Date
20260512
Application Date
20240304

Claims (8)

  1. 1. The base structure for the pendulum shaft type cable saddle comprises a base body (1), wherein the base body (1) is provided with a cross beam (12) which protrudes upwards and is used for supporting the cable saddle body; the method is characterized in that: The base body (1) is of a non-quenched and tempered structure; The base structure further comprises a bearing key (2) with a hardening and tempering structure, the bearing key (2) is connected to a cross beam (12) of the base body (1), and the bearing key (2) is exposed out of a bearing surface (22) with an arc-shaped curved surface structure on the top side of the base body (1); A key groove (15) with a downward concave structure is formed in the top side of the cross beam (12) of the base body (1); The lower part of the bearing key (2) is provided with a key body (21), the key body (21) is embedded in a key groove (15) at the top of the cross beam (12) in an interference fit manner in the width direction, and the upper part of the bearing key (2) extends out from the top of the cross beam (12); The end faces of the two ends of the length of the bearing key (2) are provided with air dispersing grooves (23) with inner groove structures; The bearing key (2) is embedded in a key groove (15) at the top of the cross beam (12) in an interference manner, the inside and the outside of the key groove (15) are communicated through air dispersing grooves (23) at two ends, and air in the key groove (15) is discharged in the interference embedding of the bearing key (2); When the saddle body of the cable saddle is located on the base structure, the bearing surface (22) of the bearing key (2) and the bottom of the saddle body form relative rolling fit relation.
  2. 2. The base structure for a pendulum suspension saddle according to claim 1, wherein: The upper part of the bearing key (2) is provided with wing parts (24) which are formed by extending from two sides of the width direction of the key body (21), and the top surface of the wing parts (24) and the top surface of the key body (21) jointly form a bearing surface (22) with an arc-shaped curved surface structure; The bearing key (2) is embedded in the key groove (15) at the top of the cross beam (12) in an interference manner, and wing parts (24) at two sides in the width direction are correspondingly located on the opening edges (16) at two sides in the width direction of the key groove (15) in a surface contact manner.
  3. 3. The base structure for a pendulum suspension saddle according to claim 2, wherein: The depth of a key groove (15) at the top of the cross beam (12) is at least 1/2 of the maximum height of the bearing key (2); The effective embedded height of the key body (21) of the bearing key (2) is at least 1/2 of the maximum height of the bearing key (2); When the bearing key (2) is embedded in a key groove (15) at the top of the cross beam (12) in an interference manner, the bottom surface of a key body (21) of the bearing key (2) and the bottom surface of the key groove (15) form a surface contact matching relationship.
  4. 4. A pendulum-type cable saddle base structure according to claim 2 or 3, wherein: the two ends of the cross beam (12) in the length direction are provided with baffle heads (14) which extend upwards beyond the opening edges (16) of the key groove (15) in the width direction; When the bearing key (2) is embedded in a key groove (15) at the top of the cross beam (12) in an interference manner, the blocking heads (14) at the two ends of the cross beam (12) in the length direction respectively extend upwards to exceed the bearing surface (22) of the bearing key (2); When the saddle body of the cable saddle is located on the base structure, the bearing surface (22) of the bearing key (2) between the stop heads (14) at the two ends of the cross beam (12) and the bottom of the saddle body form a relative rolling fit relation.
  5. 5. A pendulum-type cable saddle base structure according to claim 2 or 3, wherein: the length of a key groove (15) at the top of the cross beam (12) is more than or equal to 2m; The bearing keys (2) which are embedded in the key grooves (15) at the top of the cross beam (12) in an interference manner are divided into relatively independent sections in the length direction, and the length of each bearing key section is 0.5-1.5 m; the bearing key sections of the multiple sections are sequentially butted in the key grooves (15) according to the relative arrangement positions, and the fit clearance between the bearing key sections of the adjacent two sections is less than or equal to 0.05mm.
  6. 6. The base structure for a pendulum suspension saddle according to claim 1, wherein: the base body (1) is of a casting molding structure of low-carbon steel and is provided with a bottom plate (11), a cross beam (12) and a plurality of support rib plates (13); The top profile of the bottom plate (11) is of a rectangular structure; the cross beams (12) are arranged at the width center of the bottom plate (11) along the length direction of the bottom plate (11); The support rib plates (13) are divided into two groups, a plurality of support rib plates (13) of each group are distributed between the bottom plate (11) and the cross beam (12) at intervals along the length direction of the cross beam (12), the outline of the support rib plates (13) is of a triangular or trapezoid structure with narrow top and wide bottom, and the top side of the support rib plates (13) is lower than the top side of the cross beam (12).
  7. 7. A base structure for a rocking axle type cable saddle as set forth in claim 1, 2 or 3, wherein: the bearing bond (2) is a forging forming structure of low alloy steel or alloy steel.
  8. 8. A method of forming a base structure for a pendulum suspension saddle as set forth in any one of claims 1 to 7, wherein the forming method comprises forming the base body and the load-bearing key separately, and then interference-fitting the load-bearing key to the corresponding base body; The forming of the base body comprises the following process steps: step1, forming a base body blank by adopting low-carbon steel in a die casting mode according to the design structure of the base body; step 2, carrying out normalizing heat treatment and tempering heat treatment on the base body blank formed by casting in sequence; The normalizing heat treatment process is as follows: ①, when the temperature in the heat treatment furnace is less than or equal to 300 ℃, placing the base body blank into the heat treatment furnace; ②, raising the temperature in the heat treatment furnace to 600-650 ℃ at a temperature raising speed of less than or equal to 80 ℃ per hour, and preserving heat for 2-3 hours; ③, raising the temperature in the heat treatment furnace to 885-915 ℃ at the temperature raising speed of less than or equal to 80 ℃ per hour, preserving heat (delta/100 mm) for 4 hours, and taking out and cooling; the tempering heat treatment process comprises the following steps: ①, when the temperature in the heat treatment furnace is less than or equal to 300 ℃, placing the base body blank subjected to the normalizing heat treatment into the heat treatment furnace; ②, raising the temperature in the heat treatment furnace to 590-610 ℃ at the temperature raising speed of less than or equal to 70 ℃ per hour, preserving heat (delta/100 mm) for 4 hours, and taking out and cooling; step 3, according to the design structure of the bearing key assembly, finishing a key groove with a concave structure at the top of the base body blank beam subjected to tempering heat treatment, so that the dimensional tolerance of the key groove in the width direction is matched with the interference assembly technical requirement of the bearing key assembly; step 4, ultrasonic and magnetic powder inspection is adopted on the processing surface of the base body until the processing surface is qualified; the forming of the bearing key comprises the following process steps: step A, forming a bearing key blank by adopting low alloy steel or alloy steel in a forging mode according to the design structure of the bearing key; step B, rough machining the forge piece in the step A to a rough part of the bearing key according to the design structure of the bearing key; step C, carrying out ultrasonic and magnetic powder inspection on the processing surface of the coarse piece of the bearing key until the processing surface is qualified; step D, carrying out quenching and tempering heat treatment and induction surface quenching treatment on the bearing key crude piece qualified in flaw detection in sequence; The tempering heat treatment process comprises the following steps: ①, when the temperature in the tempering furnace is less than or equal to 300 ℃, placing the crude bearing key into the tempering furnace; ②, raising the temperature in the quenching and tempering furnace to 600-650 ℃ at a temperature raising speed of less than or equal to 80 ℃ per hour, and preserving heat for 2-3 hours; ③, raising the temperature in the quenching and tempering furnace to 845-875 ℃ at the temperature raising speed of less than or equal to 80 ℃ per hour, carrying out heat preservation (delta/100 mm) for 4 hours, and taking out the quenching and tempering furnace to carry out sufficient water cooling or oil cooling to finish quenching heat treatment; ④, when the temperature in the quenching and tempering furnace is less than or equal to 300 ℃, placing the crude bearing bond after quenching heat treatment into the quenching and tempering furnace; ⑤, raising the temperature in the tempering furnace to 550-570 ℃ at the temperature raising speed of less than or equal to 70 ℃ per hour, and taking out and cooling after heat preservation (delta/100 mm) for 4 hours to finish tempering heat treatment; the induction surface quenching treatment process comprises the following steps: ①, when the temperature of the sensor is 140-160 ℃, placing the bearing key crude piece subjected to quenching and tempering heat treatment into the sensor; ②, raising the temperature of the sensor to 640-660 ℃ at a temperature raising speed of less than or equal to 80 ℃ per hour, and fully preheating the coarse bearing key; ③, heating the crude bearing key and performing high-pressure water jet cooling to finish induction surface quenching treatment by increasing the temperature of the inductor to 850-870 ℃ at a temperature increasing speed of less than or equal to 80 ℃ per hour; ④, when the temperature of the inductor is less than or equal to 100 ℃, placing a bearing key crude piece subjected to induction surface quenching treatment into the inductor, increasing the temperature of the inductor to 390-410 ℃ at the heating rate of less than or equal to 70 ℃ per hour, taking out and cooling after heat preservation (delta/100 mm) for 4 hours, and finishing induction tempering treatment; or when the temperature in the heat treatment furnace is less than or equal to 100 ℃, placing the bearing key crude piece subjected to induction surface quenching treatment into the heat treatment furnace, increasing the temperature in the heat treatment furnace to 390-410 ℃ at the heating rate of less than or equal to 70 ℃ per hour, taking out and cooling after heat preservation (delta/100 mm) for 4 hours, and finishing the whole tempering treatment in the furnace; Step E, carrying out finish machining treatment on the rough part of the bearing key with good quality, so that the dimensional tolerance of the bearing key in the width direction is matched with the interference assembly technical requirement of the base body assembly; the interference fit of the bearing key on the base body comprises the following process steps: Step I, placing the bearing key into liquid nitrogen to perform uniform cold contraction; II, embedding the cold-contracted bearing key into a key slot at the top of the cross beam on the base body; If the bearing keys are relatively independent sections, the sections of the bearing keys are sequentially embedded into key grooves at the top of the cross beam on the base body according to arrangement positions, the fit clearance between two adjacent sections of the bearing keys is less than or equal to 0.05mm, and the bearing keys are inspected by a feeler gauge; III, carrying out finish machining on the bottom plane of the base body according to the anchored design structure; and carrying out arc-shaped curved surface finish machining on the top surface of the bearing key on the base body according to the design structure of the rolling pendulum shaft and the bottom plane of the base body.

Description

Base structure for pendulum shaft type cable saddle and forming method thereof Technical Field The invention relates to a saddle assembly structure of a suspension bridge, in particular to a base structure for a pendulum shaft type loose saddle and a forming method of the base structure. Background The cable saddle is an important bearing member for supporting, steering and diverging a main cable in a suspension bridge structure, and mainly comprises an upper saddle body, a lower saddle body and a base. In order to adapt to the load change of the main cable, a relatively rolling pendulum shaft type matching relation is formed between the saddle body and the base of the cable saddle, namely, the saddle body can swing forwards and backwards along the extending direction of the main cable on the base according to the stress condition of the main cable. The saddle body and the base of the pendulum shaft type cable saddle are movably connected together by an upper bearing plate assembled in a groove at the bottom of the saddle body, a lower bearing plate assembled in a groove at the top of the base and a plurality of conical steel pins penetrating between the upper bearing plate and the lower bearing plate along the transverse interval of the base (relative to the longitudinal direction of the extension of a main cable). The bottom surface of the upper bearing plate is of a plane structure, the top surface of the lower bearing plate is of an arc-shaped curved surface structure, the conical steel pin is divided into a cylindrical section and a conical section on the axial length, the cylindrical section is used for being installed in the lower bearing plate, and the conical section is used for being installed in the upper bearing plate, so that the bottom plane of the upper bearing plate and the top arc surface of the lower bearing plate form linear contact fit, and movable connection of the saddle body on the base in relative rolling fit is realized. The working principle of the pendulum shaft connection technology of the cable saddle is as follows: When the upper bearing plate is in the horizontal position, the circumference of the conical section of the conical steel pin (especially the upper part of the conical steel pin) is not contacted with the round hole of the upper bearing plate, but forms a certain annular space; when the bottom plane of the upper bearing plate rotates along the top cambered surface of the lower bearing plate by a certain angle, the conical steel pin is in contact extrusion with the hole wall of the round hole of the upper bearing plate, so that the upper bearing plate is limited to continue to rotate along the arc-shaped cambered surface of the lower bearing plate. The swing shaft connection technology of the cable saddle comprises the following steps of forming a structure too complex, and ensuring that the manufacturing and the installation are inconvenient due to the large number of parts, and two steps of using a conical steel pin as a positioning and limiting device, wherein in the use process, in order to limit the conical steel pin and prevent the saddle body from rotating continuously, the conical steel pin is contacted with the hole wall of a round hole of an upper bearing plate and then bears very large extrusion and shearing force, the acting force can easily cause fatigue damage to the conical steel pin as a key part of the movable connection structure in long-term service, the safety and the reliability of the whole cable bridge structure are affected, and the three steps of determining that the rotation angle of the saddle body on a base is small and even the rotation is difficult, and easily causing that the cable saddle cannot be reliably converted and adjusted effectively and flexibly according to dynamic load changes born by the cable bridge, and affecting the uniformity of stress of each cable strand of a main cable and the safety and the reliability of the cable bridge structure. In view of the above, the present inventors have disclosed a saddle structure in which a cross member formed by protruding on a base is used as a swing shaft to support a saddle, and have disclosed a technique called a "swing shaft saddle" (publication No. CN 105220614A, publication No. 2016, 01/06), and a "novel swing shaft saddle" (publication No. CN 217758339U, publication No. 2022, 11/08), which are disclosed in chinese patent literature. The technology effectively solves the technical problems of the pendulum shaft connection technology in the conical steel pin structure mode. However, the present inventors have found in repeated studies that the main cable load carried by the saddle body of the cable saddle is transmitted to the support beam on the base at first, thereby making the contact stress at the top side arc-shaped curved surface of the support beam high. In order to enable the base to bear high strength and enable the supporting beam to achieve the surface hardness required