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Improvement of Hydraulic Rope Adjusting Clutch of Double Drum Hoist

Issuing time:2021-06-09 13:49

Improvement of hydraulic rope adjusting clutch for double-drum hoist


ZHU Youliang1,NIU Guoqiang1,SU Wenzhou1,KOU Baofu2


1Hebi Wanfeng Mining Machinery Manufacturing Co., Ltd., Hebi 456761, Henan, China


2College of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, Shanxi, China


Abstract: The safe and reliable operation of the hydraulic rope adjusting clutch is an important guarantee for the efficient operation of the double-drum hoist. Due to the unreasonable rotation coordination and lubrication mode between the toggle ring and the moving hub in the hydraulic rope adjusting clutch, the oil leakage is often caused and thrown onto the brake disc, affecting the braking effect; when the environment is bad or the lubrication is not sufficient, the local part is easy to dry and cause the scuffing accident. In view of the above problems, the author puts the friction and rotation matching mode of the sliding surface between the toggle ring and the moving hub as improving the rolling friction of double balls, reducing the contact friction area, increasing the lubrication space between the toggle ring and the moving hub, reducing greatly the friction and wear degree; at the same time, a special grease storage and transmission channel is set up, further improving its working conditions. Theoretical analysis and field application show that the improvement of the hydraulic rope adjusting clutch fundamentally avoids the lifting safety accident caused by the rope adjusting clutch, and greatly reduces the maintenance cost and time of the rope adjusting clutch.


Key Words: rope adjusting clutch; toggle ring; moving hub; lubrication mode; rotating contact friction


Rope adjustment is often required when the main shaft device of the double-drum hoist is working, especially when it is used for multi-level hoisting operations, the number of rope adjustments is more frequent [1]. The hydraulic rope adjusting device is an important mechanism in this component, and its structural rationality and operational safety and reliability are directly related to the completion of the lifting task of the whole machine and the level of work efficiency [2].


Commonly used double-cylinder rope adjusting clutch mechanisms include: support wheel connection type, worm gear type, axial gear type and radial gear type, etc. [3]. Among them, the supporting wheel-connected rope adjusting clutch mechanism is cumbersome to operate, and the labor intensity of the operator is high; the worm gear type rope adjusting clutch mechanism is time-consuming and time-consuming to adjust, and due to the structural asymmetry, it is easy to cause unbalanced torque when the main shaft device rotates; axial gears In addition to completing the clutch action, the rope adjusting hydraulic cylinder of the type rope adjusting clutch mechanism is also responsible for transmitting torque. After a period of use, the cylinder body is squeezed and deformed, resulting in serious oil leakage, and the leaked oil can easily flow to the brake disc. Affect the braking effect [4]; the radial gear type rope adjusting clutch mechanism is convenient for teeth, the rope adjusting is faster, more reliable, and easy to realize automatic control; therefore, the radial gear type rope adjusting clutch mechanism is currently the more Advanced rope adjusting clutch.


The radial gear type rope adjusting clutch has several key lubrication points: the sliding mating surface between the movable hub and the hub, the sliding mating surface between the tooth block and the sliding groove, and the rotating mating surface between the dial ring and the movable hub. At present, the rotating mating surface between the dial ring and the movable hub of the radial gear type rope clutch usually adopts a sliding friction pair. Because it has been in a frequent rotation work state, it must be given sufficient oil lubrication to reduce its wear and prevent the occurrence of glue jams. Prevent accidents; during the on-site application of oil lubrication, the excess oil will often be thrown out, and even adhere to the brake disc, causing the braking effect to decrease.


In response to the above problems, the author puts forward a new type of radial rope adjustment clutch mechanism through field investigation, which fundamentally solves the problems of wear and glue between the dial ring and the movable hub in the rope adjustment clutch mechanism or rare lubrication thrown out.


1 Radial rope adjusting clutch structure and working principle


The radial rope-adjusting clutch is an important mechanism for the double-drum hoist to adjust the length of the wire rope. It is installed on the left side of the traveling drum (as shown in Figure 1). The fixed reel on the right is connected with the main shaft by a supporting wheel interference, and it rotates with the main shaft when lifting; while there is a clearance fit between the moving reel and the main shaft, and the power of the moving reel and the main shaft to rotate together comes from The meshing between the upper tooth block of the rope adjusting clutch and the inner gear ring of the rigid connection of the main shaft, the hub of the rope adjusting clutch and the main shaft adopt an interference connection. During the operation of the hoist, when the hoisting container cannot reach the designated loading and unloading position or the elastoplastic elongation of the hoisting wire rope will seriously affect the accurate placement of materials or personnel, the moving drum must be separated from the main shaft by a rope adjusting clutch. Thereby adjusting the length of the wire rope, changing the lifting position or replacing the wire rope.


1605162032199519.png


1. Rope adjusting clutch 2. Moving drum 3. Fixed drum 4. Support wheel 5. Main shaft

Figure 1 The main shaft device of the double-tube mine hoist


The radial tooth block type rope adjusting clutch makes the rope adjusting process faster and more reliable. The rope adjustment accuracy of this clutch is up to 50 mm. The device is composed of three parts: gear block, inner gear ring and other working mechanisms, oil cylinder, moving hub and other driving mechanisms, and operation interlocking and other control mechanisms. as shown in picture 2. In addition, the inner gear ring and the web of the traveling drum are rigidly connected by high-strength bolts.


1605162037561951.png

1. Drive cylinder 2. Moving hub 3. Switch 4. Toggle ring 5. Fixed hub 6. Tooth block

7. Inner gear ring 8. Switch 9. Solenoid valve 10. Interlock valve 11. Stop valve 12. Connecting rod

Figure 2 Rope adjusting clutch


Working principle: (1) During daily lifting operations, the drive oil cylinder fixed on the left end bearing seat pushes the mobile hub to slide along the main shaft on the fixed hub, thereby driving the connecting rod and causing the tooth block to slide along the vertical chute of the fixed hub to make The tooth block meshes with the inner gear ring, as shown in the figure in a working state. At this time, the power is transmitted from the main shaft to the outer gear ring, and then to the gear block, and is transmitted to the movable drum through the sliding grooves on both sides. The main shaft drives the drum to rotate together to complete lifting or lowering tasks. (2) When adjusting the rope length, the brake first locks the drum brake disc, and drives the hydraulic cylinder to pull the mobile hub to slide along the main shaft on the fixed hub, thereby driving the connecting rod to separate the gear block from the inner ring gear, as shown in b Working status. The rope adjustment operation can be carried out.


2 Existing problems and analysis


2.1 Analysis of problems caused by lubrication methods


Under normal operation of the hoist (non-rope adjustment state), the toggle ring and the movable hub are always in a complete sliding friction pair rotation, and sufficient lubrication between the two is very important. Therefore, there is usually a rare lubrication of an oil cup here. To ensure sufficient lubrication, it needs to be refilled or filled from time to time. However, because there is no oil collection and oil storage structure, it is easy to leak when filling the lubricating oil. The oil leaked to the brake disc will affect the braking effect; it brings great safety hazards to the parking brake of the hoist.


2.2 Analysis of the problems caused by the rotation cooperation method


When the hoist is running, the toggle ring and the movable hub are always in a complete sliding friction pair rotation. Once the lubrication is not timely, it will cause serious wear between the two; when the environment is bad, the toggle ring and the movable hub Sometimes parts of it are prone to lack of oil and dry out, and glue will occur, which will cause unsmooth rotation between the toggle ring and the movable hub, and even different degrees of jamming. In extreme cases, it will cause the tooth block in the rope adjustment clutch mechanism. It cannot be reliably meshed with or separated from the inner gear ring, causing production accidents.


3 Improved scheme of hydraulic rope adjusting clutch


In view of the problems existing in the hydraulic rope adjusting device mechanism, the author proposes a new type of rope adjusting clutch mechanism, which improves the rotation fit between the dial ring and the movable hub of the hydraulic rope adjusting device into a ball bearing point contact rolling fit structure. In order to reduce the friction between the two; using grease lubrication and supplemented by oil storage channels, fundamentally solve the poor braking effect caused by oil leakage, and avoid safety accidents such as the bonding of the rotating pair between the two.


3.1 The composition of the new rope-adjusting clutch


The hydraulic rope adjuster of the new double-cylinder hoist designed by the author is shown in Figure 3.

1605162043185188.png

a)

1605162043184903.png

b)


1. Bearing seat 2. Spindle 3. Fixed hub 4. Movable hub 5. Ball 6. Toggle ring

7. Connecting rod 8. Tooth block 9. Internal gear ring 10. Traveling drum 11. Pressure injection cup position

12. Filling channel 13. Moving channel 14. Lubricating channel 15. Lubricating pipe 16. Sleeve

Figure 3 Hydraulic rope adjuster for the new double-cylinder hoist


Fig. 3a is a schematic diagram of the overall structure, and Fig. 3b is a partial enlarged view of the rotational cooperation between the dial ring and the movable hub. The difference between the new rope-adjusting clutch and the original rope-adjusting clutch lies in the coordination and lubrication between the movable hub, the toggle ring and the fixed hub.


There is less sliding action between the fixed hub and the moving hub. This sliding action is only performed when rope adjustment is required. The lubrication method adopts grease lubrication with oil storage channels. The grease storage and grease supply channels are shown in Figure 3b. Show.


The matching method between the movable hub and the dial ring is changed from the original complete sliding friction to a point contact rolling matching mechanism similar to a double row ball bearing. The toggle ring is embedded in the annular groove of the moving hub, and a ball is added between the toggle ring and the moving hub, and a ball groove is provided on the moving hub. The ball can rotate freely in the ball groove; the toggle ring, ball, and The moving hubs are lubricated with grease, and there is a dedicated grease storage channel (see Figure 3b). After the rope adjusting drive cylinder pushes and pulls the toggle ring, the toggle ring transmits the pushing and pulling force to the moving hub through the two end faces of the annular groove on the moving hub.


The lubricating grease channel includes a pressure injection cup position, a filling channel, a moving channel and a lubrication channel. The pressure injection cup position is set on the outer end side of the sliding sleeve. The pressure injection cup position is connected with the vertical filling channel, and the filling channel is connected to the horizontal One end of the moving passage is connected with a welding plug, the moving passage is connected with the vertical lubrication passage, one end of the lubricating passage is connected between the moving hub and the dial ring, and the other end of the lubricating passage is connected to the moving hub and Fix between the hubs.


3.2 The working principle of the new rope-adjusting clutch


The working principle of the new rope adjusting clutch is similar to that of the existing rope adjusting device. During daily lifting operations, the rope adjusting hydraulic cylinder pushes the toggle ring, and the toggle ring transmits the thrust to the movable hub through the right end surface of the annular groove on the movable hub , Thereby driving the connecting rod hinged with the moving hub, and the connecting rod drives the gear block to move up in the guide groove of the fixed hub, thereby completing the meshing of the gear block and the inner gear ring. Under the normal working condition of the hoist, a double row ball bearing lubricated with grease is installed between the movable hub and the dial ring. The rotation between the two is more flexible and does not block, which greatly reduces the friction damage. It has fundamentally improved its safety and stability.


During the rope adjustment operation, the rope adjustment hydraulic cylinder pulls the toggle ring, and the toggle ring transmits the pulling force to the moving hub through the left end surface of the annular groove on the moving hub, thereby driving the connecting rod hinged with the moving hub, and the connecting rod drives the tooth block in The guide groove of the fixed hub moves down to complete the separation of the tooth block and the inner gear ring, which is convenient for the adjustment of the wire rope.


A channel is drilled on the movable hub, including the oil cup position that presses the grease, and then the grease is pressed to the filling channel through the oil cup position. The moving channel moves the grease from the filling channel to the lubrication channel, and then transports it to the lubrication channel. Both ends of the lubrication channel, namely between the movable hub and the dial ring and between the movable hub and the fixed hub, the filling channel, the movable channel and the lubrication channel are all straight up and down mechanisms to facilitate drilling on the movable hub.


3.3 Analysis of key parameters


The friction factor between the movable hub, the toggle ring and the fixed hub in the new rope-adjusting clutch is a very important parameter for the rope-adjusting clutch in the normal working condition of the hoist. The friction factors of the movable hub, the toggle ring and the fixed hub determine the degree of frictional damage between them, which has an extremely important impact on the failure rate and safety of the rope-tuning clutch.


There is sliding friction between the dial ring of the original rope-tuning clutch and the movable hub. The sliding friction factor is related to the material of the contacting object, the smoothness of the surface, the degree of dryness and wetness, the surface temperature, and the relative movement speed [5]. Therefore, the original rope-adjusting clutch has extremely high requirements for lubrication and is also extremely sensitive to temperature rise. Once the lubrication is insufficient or the local temperature rise is large, it is very easy to cause serious wear and damage or even adhesion accidents.


There is rolling friction between the toggle ring and the movable hub in the new rope-tuning clutch developed by the author. Related literature [6] established a sliding friction coefficient calculation model based on the thermal-mechanical coupling process of the friction interface. The calculation results show that the sliding friction coefficient increases with the increase of the relative sliding speed; when the actual contact area of the friction interface is in a linear relationship with the load, The sliding friction coefficient has nothing to do with the contact area; when the actual contact area is close to the nominal contact area, the sliding friction coefficient decreases as the load increases. Rolling friction means that the contact surface of an object is constantly changing when it rolls, and the friction force experienced by the object is essentially static friction. The contact surface is soft, and the greater the shape change, the greater the rolling friction. The rolling friction between objects is much smaller than the sliding friction. It can be seen that the contact working condition between the toggle ring and the movable hub in the new rope-tuning clutch has been greatly improved, which greatly reduces the friction and wear between the two.


The coefficient of sliding friction between the toggle ring and the movable hub in the original rope adjuster: (steel-cast iron) is 0.05~0.15 under the fully lubricated state; the coefficient of rolling friction between the toggle ring and the movable hub in the original rope adjuster: (quenched) Steel-hardened steel) is 0.001 under lubrication; the ratio of sliding friction to rolling friction before and after the improvement is: 0.05/0.001=50. Under the same operating conditions, the contact wear between the toggle ring and the movable hub in the original rope-tuning clutch is 50 times that of the existing one.


3.4 Advantages and field application of the new rope-tuning clutch


Advantages of the new type of rope-adjusting clutch: The rotation fit between the toggle ring and the movable hub is improved to a double row ball bearing point contact rolling fit mechanism, that is, the original sliding surface friction is double rolling friction, which reduces the contact area and increases at the same time The lubrication space between the toggle ring and the movable hub greatly reduces the degree of friction and wear; a dedicated grease storage and grease channel is set up to further improve the matching conditions between the toggle ring and the movable hub. Fundamentally, the lifting safety accident caused by the rope adjusting clutch is avoided, the maintenance cost and time of the rope adjusting clutch are greatly reduced, and its service life is prolonged.


The new rope-adjusting clutch has been applied to a 2JK3.0×1.5P double-cylinder single-rope winding hoist in a mine in Ningyang County, Shandong Province. After use, there is no abnormal noise or failure, and the effect is good, and there is no hidden danger of safety accidents.


4 Conclusion


In view of the oil leakage and serious wear of the hydraulic rope adjustment clutch of the current double-cylinder single rope winding hoist, the author has improved the design, focusing on the rotation and lubrication between the dial ring and the movable hub in the rope adjustment clutch. The method has been newly designed, and its rationality has been verified by theoretical analysis and field application.


The improvement of the new rope adjusting clutch effectively reduces its failure rate, saves maintenance costs, and improves the safety and reliability of the lifting system. It has good promotion and application value.



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