Method for verifying action reliability of safety brake of ladle crane

Abstract

The invention discloses a method for verifying the action reliability of a safety brake of a ladle crane. According to the method, temperature sensors are mounted on disc brake friction plates of a working brake and the safety brake respectively; the safety brake and the working brake are controlled to be switched on simultaneously, a no-load function test is conducted on the hoisting mechanism, and the temperatures of brake friction plates of the working brake and the safety brake are collected and recorded; the hoisting mechanism restores to the real-time environment temperature after being shut down; setting the delay action time of the safety brake, carrying out a no-load function test on the hoisting mechanism, and collecting and recording the temperatures of the working brake and the brake friction plate of the safety working brake; the temperatures of the brake friction plate under two working conditions are compared to verify whether the electric delay command signal of the safety brake is correct or not, and the action is reliable. The method can quickly judge whether the mechanical action of the safety brake of the ladle crane is delayed, ensures that the working brake acts earlier than the safety brake, avoids the impact load of a transmission system, and ensures the equipment safety of the ladle crane.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical equipment diagnosis, and particularly relates to a method for verifying the action reliability of a safety brake of a foundry crane. Background Art

[0002] The "Safety Technical Code for Lifting Appliances" (TSG 51-2023) stipulates that for the hoisting mechanism used for lifting molten metal, when there is no rigid connection on the output shaft of two sets of driving devices, or when only one set of driving devices is provided, safety brakes shall be installed on the wire rope drum. For the hoisting mechanism equipped with safety brakes, when the working brake acts during normal operation, the safety brake acts with a time delay, and the time delay can be adjusted; if an abnormal situation occurs and an emergency brake is applied, the safety brake shall follow the action of the working brake.

[0003] The braking of a crane converts the kinetic energy during the movement of the crane into heat energy through a braking device, so as to achieve the purpose of stopping or decelerating.

[0004] The braking device of a foundry crane usually includes a braking motor, a brake valve, etc. When the crane needs to stop or decelerate, the operator operates the braking device through the brake switch on the console. When the braking device works, the braking motor starts to generate electromagnetic force to tighten the brake. The tightening of the brake presses the friction plate inside the brake against the brake disc, causing the brake disc to stop rotating, and the rotating or lifting part of the crane will stop or decelerate. The pressing force of the friction plate on the brake disc depends on the current intensity of the braking motor. Increasing the current can increase the pressing force of the brake, thereby achieving a stronger braking effect. During the operation of the braking device, the brake will generate a certain amount of frictional heat.

[0005] In short, the braking principle of a crane is to convert the kinetic energy of the crane into heat energy through a braking device to achieve the purpose of stopping or decelerating. The braking device adjusts and protects the braking effect by controlling the current intensity of the braking motor and using a brake valve.

[0006] The safety brake of a foundry crane adopts a normally open hydraulic brake. The brake release gap is maintained within the range of 1-4 mm. The special disc spring applies force for braking, and the hydraulic drive releases it. The action is sensitive, and the closing and braking time is short. Under normal operating conditions, as long as the main power supply of the crane is turned on and all interlock links are normal, the safety brake is always in the energized and open state.

[0007] When the hoisting mechanism is running at high speed and receives the braking commands of the safety brake and the working brake, both brakes are applied simultaneously. Since the inherent action time of the safety brake to apply the brake is fast and the braking torque is large, the low-speed shaft stops rotating quickly, thus causing a large impact load on the transmission system. This impact load often damages a certain part of the transmission chain, especially the parts at the weak links are more likely to be damaged. In order to avoid causing a large impact load, the "Safety Technical Code for Hoisting Machinery" requires that after the working brake operates during normal operation, the safety brake operates with a time delay, and the time delay can be adjusted. The time delay operation of the safety brake is adjusted through electrical control. However, in actual operation, due to reasons such as the setpoint drift of electrical components, the safety brake with electrical control operates with a time delay, and the safety brake applies the brake before the working brake. The inherent action time of the safety brake to apply the brake is about 0.2 s - 0.4 s, and the inherent action time of the working brake to apply the brake is about 0.5 s - 0.7 s. The safety brake closes first, generating a large impact load on the transmission chain, resulting in damage to mechanical components. The time delay operation time of the safety brake is generally set at 0.6 seconds, which can ensure that the working brake applies the brake first. All along, whether the safety brake operates with a time delay and whether the working brake applies the brake first cannot be reliably verified mechanically. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a method for verifying the action reliability of the safety brake of a foundry crane, which can quickly determine whether the mechanical action of the safety brake of the foundry crane is delayed, ensure that the working brake acts before the safety brake, avoid the impact load of the transmission system, and ensure the safety of the foundry crane equipment.

[0009] To solve the above technical problem, the method for verifying the action reliability of the safety brake of the foundry crane of the present invention includes the following steps: Step 1: Install a first temperature sensor and a second temperature sensor on the disc brake friction plates of the working brake and the safety brake of the foundry crane respectively. Step 2: By adjusting the electrical control of the hoisting mechanism of the foundry crane, the safety brake and the working brake receive synchronous braking commands, and the safety brake and the working brake are applied simultaneously. Conduct an idle function test on the hoisting mechanism. Three minutes after the test ends, collect and record the temperatures t1 and t2 of the temperature sensors of the brake friction plates of the working brake and the safety brake respectively. Step 3: After the hoisting mechanism of the foundry crane stops for 30 minutes, wait for the temperatures of the working brake and the safety brake to return to the real-time ambient temperature. Step 4: By adjusting the electrical control of the hoisting mechanism of the foundry crane, set the delay action time of the safety brake to 0.6 seconds after the service brake is applied. Conduct an unloaded function test on the hoisting mechanism. Three minutes after the test ends, collect and record the temperatures t3 and t4 of the brake friction plate temperature sensors of the service brake and the safety service brake respectively; Step 5: Compare the temperatures of the brake friction plate temperature sensors in the above two working conditions. If t1 is less than t3 and t2 is greater than t4, then the electrical delay command signal of the safety brake is correct and the action is reliable, and it can be applied to the brake actuator of the foundry crane. Otherwise, the braking action of the safety brake is abnormal.

[0010] Furthermore, the first temperature sensor is installed on the disc brake friction plates on both sides of the brake disc of the service brake, and the second temperature sensor is installed on the disc brake friction plates on both sides of the brake disc of the safety brake. Since the method for verifying the action reliability of the safety brake of the foundry crane of the present invention adopts the above technical solution, that is, temperature sensors are respectively installed on the disc brake friction plates of the service brake and the safety brake of this method; control the service brake and the safety brake to apply the brakes simultaneously, conduct an unloaded function test on the hoisting mechanism, collect and record the temperatures of the brake friction plates of the service brake and the safety brake; after the hoisting mechanism stops, it returns to the real-time ambient temperature; set the delay action time of the safety brake, conduct an unloaded function test on the hoisting mechanism, collect and record the temperatures of the brake friction plates of the service brake and the safety service brake; compare the temperatures of the brake friction plates in the two working conditions to verify whether the electrical delay command signal of the safety brake is correct and the action is reliable. This method can quickly determine whether the mechanical action of the safety brake of the foundry crane is delayed, ensure that the service brake acts before the safety brake, avoid the impact load of the transmission system, and ensure the safety of the foundry crane equipment. Description of the Drawings

[0011] The following further elaborates the present invention in detail in conjunction with the drawings and embodiments: Figure 1 It is a schematic diagram of installing a brake friction plate temperature sensor on the disc brake of the crane in this method. Detailed Embodiments

[0012] For example Figure 1 As shown, the method for verifying the action reliability of the safety brake of the foundry crane of the present invention includes the following steps: Step 1: Install a first temperature sensor 3 and a second temperature sensor 4 on the disc brake friction plates 11 and 21 of the service brake 1 and the safety brake 2 of the foundry crane respectively; Step 2: By adjusting the electrical control of the hoisting mechanism of the foundry crane, the safety brake and the working brake receive synchronous braking commands, and the safety brake and the working brake are applied simultaneously to conduct a no-load function test on the hoisting mechanism. Three minutes after the test ends, collect and record the temperatures t1 and t2 of the temperature sensors of the brake friction linings of the working brake and the safety brake respectively; Step 3: After the hoisting mechanism of the foundry crane stops for 30 minutes, wait for the temperatures of the working brake and the safety brake to return to the real-time ambient temperature; Step 4: By adjusting the electrical control of the hoisting mechanism of the foundry crane, set the delay action time of the safety brake to 0.6 seconds after the working brake is applied, and conduct a no-load function test on the hoisting mechanism. Three minutes after the test ends, collect and record the temperatures t3 and t4 of the temperature sensors of the brake friction linings of the working brake and the safety working brake respectively; Step 5: Compare the temperatures of the brake friction linings of the temperature sensors in the above two working conditions. If t1 is less than t3 and t2 is greater than t4, the electrical delay command signal of the safety brake is correct and the action is reliable, and it can be applied to the braking actuator of the foundry crane; otherwise, the braking action of the safety brake is abnormal Preferably, the first temperature sensor 3 is installed on the disc brake friction linings 11 on both sides of the brake disc 12 of the working brake 1, and the second temperature sensor 4 is installed on the disc brake friction linings 21 on both sides of the brake disc 22 of the safety brake 2. Setting the temperature sensor on the disc brake friction linings on both sides of the brake disc improves the accuracy of the temperature detection of the disc brake friction linings. The detected temperatures of the disc brake friction linings on both sides of the brake disc can be averaged and used in the comparison of the temperatures of the brake friction linings in the two working conditions to ensure the accuracy of the verification result.

[0013] Generally, for a foundry crane, when the hoisting mechanism runs at high speed and receives the synchronous braking commands of the safety brake and the working brake, the two brakes are applied simultaneously. Since the inherent action time of the safety brake to be applied is fast and the braking torque is large, the low-speed shaft stops rotating quickly, and the temperature of the disc friction lining of the safety brake is relatively high; when the hoisting mechanism runs at high speed and receives the braking command that the safety brake delays the working brake by 0.6 seconds, since the safety brake is applied after the working brake, the braking torque is small, and after the low-speed shaft stops rotating, the temperature of the disc friction lining of the safety brake is relatively low.

[0014] Accordingly, this method collects and records the temperatures of the disc brake friction linings of the working brake and the safety brake under the two working conditions through temperature sensors and compares them, so as to verify the action reliability of the safety brake of the foundry crane; it can quickly determine whether the mechanical action of the safety brake of the foundry crane is delayed and whether the braking action is reliable, so as to ensure that the working brake acts before the safety brake, avoid the impact load of the transmission system of the foundry crane, and ensure the safety of the foundry crane equipment.

Claims

1. A method for verifying the reliability of the safety brake of a casting crane, characterized in that The steps include: Step 1: installing a first temperature sensor and a second temperature sensor on the disc brake friction pads of the working brake and the safety brake of the casting crane respectively; Step 2: By adjusting the electrical control of the hoisting mechanism of the casting crane, the safety brake and the working brake receive the synchronous brake command, the safety brake and the working brake are braked at the same time, and the no-load function test is performed on the hoisting mechanism. Three minutes after the test, the temperatures t1 and t2 of the brake friction pad temperature sensors of the working brake and the safety brake are respectively collected and recorded; Step 3: After the hoisting mechanism of the casting crane is shut down for 30 minutes, wait for the temperature of the working brake and the safety brake to return to the real-time ambient temperature; Step 4: By adjusting the electrical control of the hoisting mechanism of the casting crane, the safety brake delay action time is set to 0.6 seconds after the working brake is applied, and the no-load function test is performed on the hoisting mechanism. Three minutes after the test, the temperatures t3 and t4 of the brake friction pad temperature sensors of the working brake and the safety working brake are respectively collected and recorded; Step 5. Compare the temperatures of the brake friction pad temperature sensors under the above two working conditions. If t1 is less than t3 and t2 is greater than t4, the electrical delay command signal of the safety brake is correct and the action is reliable, and it can be applied to the brake actuator of the casting crane. Otherwise, the braking action of the safety brake is abnormal.

2. The method for verifying the reliability of the safety brake of a casting crane according to claim 1 is characterized in that: The first temperature sensor is installed on the disc brake friction pads on both sides of the working brake disc, and the second temperature sensor is installed on the disc brake friction pads on both sides of the safety brake disc.

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