Disassembly fixtures for the speed reducer and its drive shaft

Abstract

This application provides a disassembly fixture for a speed reducer and its drive shaft. The fixture includes a flange, a connector, and a top plate. The flange has a threaded hole in its center for threaded connection to the hollow shaft of the speed reducer. The top plate is connected to the flange via the connector. A receiving space is formed between the top plate and the flange, which is used to house a supporting device. The two ends of the supporting device support the top plate and the drive shaft connected to the hollow shaft, respectively, to achieve disassembly and separation of the drive shaft from the hollow shaft. This disassembly fixture, by introducing a dedicated flange, transfers the main load of the disassembly process from the speed reducer housing, aiming to protect the brittle cast iron housing from tensile failure. Its load-bearing frame is no longer the speed reducer housing itself, but an independent rigid fixture. This design achieves intrinsic safety protection for the housing, completely eliminating the possibility of damage during disassembly.

Description

Technical Field

[0001] This application relates to the technical field of auxiliary disassembly and assembly equipment, specifically to a disassembly fixture for a speed reducer and its drive shaft. Background Technology

[0002] A key spare part of the speed reducer in the pulp and paper production process is the hollow shaft. As the core functional unit of the speed reducer, this component has wide applications in the transmission system. The speed reducer transmits output torque to the hollow shaft, which connects to the solid shaft (i.e., the drive shaft, inserted inside the hollow shaft) via keyways and keys, driving the drive shaft. Ultimately, the drive shaft transmits torque to the equipment on-site, enabling it to perform mechanical work. Its structural performance directly affects the reliability and efficiency of the equipment operation.

[0003] The main structural components of a speed reducer include: a housing (casing) made of gray cast iron; a hollow shaft (for connection to the drive shaft); an input gear set; an output gear set; bearings; and a skeleton oil seal. The hollow shaft, as a key interface, transmits torque and connects the internal and external components of the transmission system through its through-type structure, providing a core channel for power transmission. During equipment operation, the hollow shaft and drive shaft of the speed reducer must maintain a precise interference fit (to prevent shaft movement) to ensure the reliability of torque transmission and the stability of the transmission system. Because the hollow shaft and drive shaft require an interference fit, the shaft is difficult to remove during disassembly, affecting maintenance efficiency. In emergencies, to avoid production disruptions, the main shaft must be cut off, increasing maintenance costs. In the continuous production process of the pulp and paper industry, over 70% of process equipment (such as pulpers, refiners, and belt conveyors) operates under low-speed, heavy-load conditions for extended periods. Such harsh working conditions can easily lead to progressive failure of critical internal components of the speed reducer (such as pitting on gear teeth, fatigue spalling of bearings, and plastic deformation of the transmission shaft). To maintain stable operation of the production line, frequent preventative disassembly and maintenance of the speed reducer is necessary.

[0004] The shortcomings of existing deceleration methods: 1. The drive shaft is prone to cracking at its stress points during disassembly: During the disassembly of the hollow shaft, a high-strength screw is first screwed into the bolt holes of the reducer housing, and a bearing pad is installed on its back to form a stable support structure. Then, a jack is used to apply jacking force along the axial direction to push out the drive shaft inside the hollow shaft. The load generated by the jack is transferred to the reducer housing through the back plate and screw. Reducers generally adopt an integral cast housing structure. The housing is mostly made of gray cast iron (tensile strength σb = 250–300 MPa, elongation δ<1%), which is significantly brittle and has poor tensile and ductile properties. During the jacking process, the housing is locally subjected to high tensile stress, making it highly susceptible to brittle fracture. Once the housing breaks, the entire reducer will be scrapped.

[0005] 2. Strict alignment accuracy requirements and high sensitivity to off-center loads: Uneven force application or off-center loads during disassembly can easily lead to stress concentration in the housing. Asymmetrical loads can further induce fretting wear and even friction welding effects between the hollow shaft and the mating surfaces, causing shaft jamming or seizing, and thread breakage, severely hindering the disassembly operation.

[0006] 3. Poor force transmission path, making the bearing system vulnerable: Under traditional disassembly methods, when tensile force is applied to the housing-bearing assembly, non-design separation is likely to occur. That is, before the rated separation force is reached, the housing separates prematurely from the hollow shaft bearing assembly, while the hollow shaft at the assembly end remains fixed, resulting in failure of the bearing cage structure, scratches and crushing of the mating surfaces of the hollow shaft and bearing. Utility Model Content

[0007] The first aspect of this application provides a disassembly fixture for a speed reducer drive shaft. The disassembly fixture includes a flange, a connector, and a top plate. The flange has a threaded hole in the middle for threaded connection with the hollow shaft of the speed reducer. The top plate is connected to the flange via the connector. An accommodating space is formed between the top plate and the flange. The accommodating space is used to place a supporting device. The two ends of the supporting device support the top plate and the drive shaft connected to the hollow shaft, respectively, for disassembling and separating the drive shaft from the hollow shaft.

[0008] In some alternative embodiments, the flange includes a central portion and an edge portion of an integral structure, the edge portion being disposed around the circumference of the central portion, the thickness of the central portion being greater than the thickness of the edge portion, and the threaded hole being disposed in the central portion.

[0009] In some alternative embodiments, the two ends of the connector are respectively connected to the edge of the flange and the top plate.

[0010] In some alternative embodiments, there are multiple connectors, which are evenly distributed along the edge of the flange.

[0011] In some alternative embodiments, a plurality of the connectors are arranged symmetrically along the axis of the flange.

[0012] In some optional embodiments, the connector is a screw, the edge of the flange is provided with a threaded hole that mates with the screw, the top plate is provided with a connecting hole for passing through the screw, and a detachable connection is achieved by a nut.

[0013] In some alternative embodiments, the flange is made of cast iron or steel.

[0014] In some alternative embodiments, the top-holding device is a hydraulic actuator.

[0015] In some alternative embodiments, the thickness of the top plate at the center is greater than the thickness of the edge.

[0016] Secondly, this application provides a speed reducer, which includes a hollow shaft and a transmission shaft inserted into and interference-fitted with the hollow shaft. One end of the hollow shaft extends to the outside of the housing and is provided with an external thread. The external thread is used to engage with the connecting threaded hole in the middle of the flange. A top plate is connected to the flange through a connector. An accommodating space is formed between the top plate and the flange. The accommodating space is used to place a top holding device. The two ends of the top holding device respectively hold the top plate and the transmission shaft, which is used to disassemble and separate the transmission shaft from the hollow shaft.

[0017] The disassembly fixture for the reducer drive shaft provided in this application transfers the main load of the disassembly process from the reducer housing by introducing a special fixture flange. This aims to protect the brittle cast iron housing from tensile failure. The load-bearing frame is no longer the reducer housing itself, but an independent rigid fixture. This design achieves inherent safety protection for the housing and completely eliminates the possibility of damage during disassembly. The introduction of the top plate structure, with its precise fit with the flange, replaces uncertain concentrated loads with stable and predictable uniformly distributed loads, ensuring the safety of the disassembly process. Improved centering and precision control, by integrating the force application point at the shaft center, means shortening the non-ideal radial force arm to zero, thereby converting the complex off-center torque into an ideal pure axial force. This precise control of force flow is the fundamental guarantee for achieving high-precision and high-reliability centering. This disassembly fixture has a simple structure, is easy to operate, and has high practical value. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the disassembly tooling of this application in conjunction with the speed reducer. Figure 2 yes Figure 1 A schematic diagram of the disassembly fixture separated from the reducer in the embodiment; Figure 3 yes Figure 1 A schematic diagram of the disassembly fixture's disassembly structure in the embodiment. Detailed Implementation

[0020] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the application. Similarly, the following embodiments are only some, not all, embodiments of the present application, and all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present application.

[0021] The terms "first," "second," and "third" used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movement of components in a specific posture (as shown in the figures). If the specific posture changes, the directional indication will also change accordingly. The terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to these processes, methods, products, or devices.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] This application provides a disassembly fixture for a speed reducer drive shaft; please refer to the following embodiments as well. Figures 1 to 3 , Figure 1 This is a schematic diagram of the disassembly tooling of this application in its mating state with the speed reducer. Figure 2 yes Figure 1 A schematic diagram of the disassembly fixture separated from the reducer in the embodiment. Figure 3 yes Figure 1 A schematic diagram of the disassembly fixture in the embodiment. The disassembly fixture 10 for the reducer drive shaft includes, but is not limited to, the following structures: flange 100, connector 200, and top plate 300.

[0024] Specifically, the reducer 20 includes a housing 21, a hollow shaft 22, and a transmission shaft 23 inserted into and interference-fitted with the hollow shaft 22. The reducer 20 may also contain components such as reduction gears and bearings. These features are within the understanding of those skilled in the art and will not be described in detail here.

[0025] One end of the hollow shaft 22 extends to the outside of the housing 21, and the extension length can be 30-100mm. The extended end of the hollow shaft 22 is provided with an external thread 22a, and the flange 100 is provided with a connecting threaded hole 101 in the middle, which is used to connect with the external thread 22a of the hollow shaft 22 of the reducer.

[0026] The top plate 300 is connected to the flange 100 via the connector 200. A receiving space 1000 is formed between the top plate 300 and the flange 100. The receiving space 1000 is used to place the top holding device (not shown in the figure). The two ends of the top holding device support the top plate 300 and the drive shaft 23 connected to the hollow shaft 22, respectively, so as to realize the disassembly and separation of the drive shaft 23 and the hollow shaft 22.

[0027] Optionally, the supporting device in this embodiment can be a hydraulic actuator, such as a jack. Both the flange 100 and the top plate 300 can be made of cast iron or steel.

[0028] Optionally, the flange 100 in this embodiment includes a central portion 110 and an edge portion 120 of an integral structure. The edge portion 120 is arranged around the circumference of the central portion 110. The overall shape of the flange 100 is a disc-shaped structure. The thickness of the central portion 110 is greater than the thickness of the edge portion 120. The threaded hole 101 is provided in the central portion 110.

[0029] The two ends of the connector 200 are connected to the edge 120 of the flange 100 and the top plate 300, respectively. Specifically, there are multiple connectors 200 (not limited to the four shown in the figure), which are evenly distributed along the edge 120 of the flange 100. Specifically, multiple connectors 200 can be symmetrically arranged along the axis of the flange 100 (i.e., the axis of the threaded hole 101). The core advantage of the new design stems from the optimization of the ejection mechanics model. Integrating the force application point at the axis means shortening the non-ideal radial force arm to zero, thereby converting the complex off-center load moment into an ideal pure axial force. This precise control of force flow is the fundamental guarantee for achieving high-precision and high-reliability alignment.

[0030] In this embodiment, the connector 120 can be a screw rod, the edge portion 120 of the flange 100 is provided with a threaded hole 102 that mates with the screw rod, and the top plate 300 is provided with a connecting hole 301 for the screw rod to pass through, and a detachable connection is achieved by a nut 302. Optionally, the thickness of the middle part of the top plate 300 is greater than the thickness of the edge, and the connecting hole 301 can be located at the edge.

[0031] The disassembly process of the disassembly fixture in this embodiment is as follows: place a jack between the top plate and the hollow shaft → ejection operation → eject the drive shaft → loosen the jack → disassemble the top plate → disassemble the screw (connector) → disassemble the flange.

[0032] The disassembly fixture for the reducer drive shaft provided in this application transfers the main load of the disassembly process from the reducer housing by introducing a special fixture flange. This aims to protect the brittle cast iron housing from tensile failure. The load-bearing frame is no longer the reducer housing itself, but an independent rigid fixture. This design achieves inherent safety protection for the housing and completely eliminates the possibility of damage during disassembly. The introduction of the top plate structure, with its precise fit with the flange, replaces uncertain concentrated loads with stable and predictable uniformly distributed loads, ensuring the safety of the disassembly process. Improved centering and precision control, by integrating the force application point at the shaft center, means shortening the non-ideal radial force arm to zero, thereby converting the complex off-center torque into an ideal pure axial force. This precise control of force flow is the fundamental guarantee for achieving high-precision and high-reliability centering. This disassembly fixture has a simple structure, is easy to operate, and has high practical value.

[0033] The above description is only a part of the embodiments of this application and does not limit the scope of protection of this application. Any equivalent device or equivalent process transformation made based on the content of this application specification and drawings, or direct or indirect application in other related technical fields, are similarly included in the patent protection scope of this application.

Claims

1. A disassembly fixture for a speed reducer drive shaft, characterized in that, The disassembly fixture includes a flange, a connector, and a top plate. The flange has a threaded hole in the middle for threaded connection with the hollow shaft of the reducer. The top plate is connected to the flange through the connector. An accommodating space is formed between the top plate and the flange. The accommodating space is used to place a supporting device. The two ends of the supporting device support the top plate and the drive shaft connected to the hollow shaft, respectively, to achieve disassembly and separation of the drive shaft from the hollow shaft.

2. The disassembly fixture according to claim 1, characterized in that, The flange includes a central portion and an edge portion of an integral structure. The edge portion is arranged around the circumference of the central portion. The thickness of the central portion is greater than the thickness of the edge portion. The threaded hole is located in the central portion.

3. The disassembly fixture according to claim 2, characterized in that, The two ends of the connector are respectively connected to the edge of the flange and the top plate.

4. The disassembly fixture according to claim 3, characterized in that, The connectors are multiple and are evenly distributed along the edge of the flange.

5. The disassembly fixture according to claim 4, characterized in that, The plurality of the connecting parts are symmetrically arranged along the axis of the flange.

6. The disassembly fixture according to claim 4, characterized in that, The connector is a screw, the edge of the flange is provided with a threaded hole that mates with the screw, the top plate is provided with a connecting hole for passing through the screw, and a detachable connection is achieved by a nut.

7. The disassembly fixture according to claim 1, characterized in that, The flange is made of cast iron or steel.

8. The disassembly fixture according to claim 1, characterized in that, The supporting device is a hydraulic actuator.

9. The disassembly fixture according to claim 1, characterized in that, The thickness of the top plate in the middle is greater than the thickness of the edge.

10. A speed reducer, characterized in that, The reducer includes a hollow shaft and a drive shaft inserted into the hollow shaft and interference-fitted with it. One end of the hollow shaft extends to the outside of the housing and has an external thread at the end. The external thread is used to connect with the connecting threaded hole in the middle of the flange. The top plate is connected to the flange through a connector. An accommodating space is formed between the top plate and the flange. The accommodating space is used to place a top holding device. The two ends of the top holding device respectively hold the top plate and the drive shaft, which is used to disassemble and separate the drive shaft from the hollow shaft.

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