Speed reducer shaft sealing structure and mounting method

Abstract

The invention discloses a speed reducer shaft sealing structure and an installation method, and belongs to the technical field of speed reducer shaft sealing. The structure comprises a replaceable shaft sleeve arranged outside a rotating shaft in a sleeving mode, an annular groove is formed in the inner wall of the shaft sleeve and provided with an O-shaped sealing ring to form a static sealing interface, and the surface of the outer circle of the shaft sleeve is subjected to hardening treatment and is in dynamic sealing fit with a framework oil seal lip. The fastening assembly reliably fixes the shaft sleeve to the shaft body through a jackscrew system with an anti-loosening structure. The replaceable wear-resistant shaft sleeve is arranged as a sacrifice part, an easily-worn sealing interface is transferred to the low-cost shaft sleeve from a high-value shaft body, a dual-sealing system and an anti-loosening fastening structure are combined, the sealing reliability is guaranteed, meanwhile, rapid maintenance and replacement during sealing failure are achieved, the downtime of equipment is greatly shortened, and the service life of the equipment is prolonged. The maintenance cost is obviously reduced, and the service life of the sealing system under severe working conditions such as heavy load and vibration is effectively prolonged.

Description

Technical Field

[0001] This invention relates to the field of gearbox shaft sealing technology, specifically to a gearbox shaft sealing structure and installation method. Background Technology

[0002] As a core component of a mechanical transmission system, the sealing performance of the input and output shafts of a speed reducer directly affects the service life and operational reliability of the equipment. In traditional speed reducer shaft seal structures, a skeleton oil seal is typically used to achieve dynamic sealing by directly contacting the rotating shaft surface. However, during long-term operation, due to factors such as shaft rotational friction, media erosion, and vibration, wear grooves are easily formed on the shaft surface, leading to seal failure. This, in turn, causes lubricating oil leakage or intrusion of external contaminants, seriously affecting the normal operation of the equipment.

[0003] In existing technologies, such as the "shaft seal structure for a speed reducer" disclosed in Chinese patent CN216343831U, the sealing effect is improved by setting up components such as a front seal, a shaft seal stationary ring, and a reinforcing cover plate, and by using adjusting shims to press the sealing structure tightly against the shaft seal stationary ring. While this structure improves sealing performance to some extent, it still has the following problems: Complex structure and inconvenient maintenance: This solution involves multiple sealing rings, gaskets and connecting parts, requiring high assembly precision, and the disassembly and replacement process is cumbersome, which is not conducive to rapid on-site maintenance; Direct contact between the shaft surface and the seal: The seal rubs directly against the shaft surface, which may still cause wear on the shaft surface after long-term operation. Repair requires replacing the entire shaft or performing welding, resulting in long downtime and high costs. Lack of replaceable wear-resistant parts: No independent wear-resistant sacrificial parts are provided. Once the sealing interface is worn, the shaft must be repaired or replaced, which is uneconomical and affects the availability of the equipment.

[0004] In addition, the adhesive residue left by traditional skeleton oil seals after wear tends to adhere to the shaft surface, exacerbating shaft surface damage, creating a vicious cycle, and further shortening the equipment life.

[0005] Therefore, there is an urgent need for a gearbox shaft seal structure that is simple in structure, highly wear-resistant, easy to replace, and can effectively isolate the shaft surface from direct contact with the seal, in order to solve the problems of high maintenance costs, long downtime, and short seal life in the existing technology. Summary of the Invention

[0006] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a gearbox shaft seal structure and installation method, which has the advantages of quick replacement of the gearbox shaft seal interface and long-term protection, and solves the problems of frequent leakage, high maintenance costs and long downtime caused by shaft surface wear in traditional seal structures.

[0007] (II) Technical Solution To achieve the goals of rapid replacement and long-term protection of the reducer shaft sealing interface, the present invention provides the following technical solution: The first aspect of the present invention provides a gearbox shaft seal structure, comprising: Replaceable bushing, fitted onto the outside of the shaft, with multiple annular grooves on its inner wall; The O-ring disposed in the annular groove is used to achieve a static seal between the bushing and the shaft. The skeleton oil seal is press-fitted into the reducer housing, and its lip is interference-fitted with the outer circular surface of the bushing to form a dynamic sealing interface. And a fastening assembly for detachably securing the bushing to the shaft; The bushing has at least two threaded holes in its radial direction for assembling the fastening assembly; The bushing, as an independent wear-resistant sacrificial component, has a hardened wear-resistant layer on its outer surface, which means that in the event of seal failure, only the bushing needs to be replaced instead of the shaft, thereby achieving rapid repair and significantly reducing maintenance costs.

[0008] The fastening assembly includes a first set screw that mates with the threaded hole, and an elastic washer is provided between the end of the first set screw and the surface of the shaft. The first set screw has an internal threaded hole along its axial direction and is equipped with an anti-loosening structure.

[0009] The anti-loosening structure includes a second set screw that mates with the internal threaded hole, and at least two radially movable retaining balls disposed inside the first set screw. The inner wall of the threaded hole is provided with an annular groove at the corresponding position; When the second set screw is screwed in, its end pushes the retaining bead to move radially outward and engages with the retaining groove.

[0010] Wherein, the first set screw and the second set screw have the same thread direction; Furthermore, once the first and second set screws are installed in place, their top ends do not protrude beyond the outer surface of the bushing.

[0011] The number of threaded holes and matching fastening components is three, and they are evenly distributed along the circumference of the bushing.

[0012] The hardened layer on the outer cylindrical surface of the bushing has a hardness of not less than HRC55 and a roughness Ra of not more than 0.4μm.

[0013] The O-ring is made of fluororubber; the ratio of the depth of the annular groove to the cross-sectional diameter of the O-ring is 0.85:1.

[0014] The wall thickness of the bushing is not less than 1 / 10 of the shaft diameter and not less than 5 mm.

[0015] A second aspect of the present invention provides a speed reducer in which at least one of its input shaft and output shaft employs the sealing structure described in the preceding aspect.

[0016] A third aspect of the present invention provides a method for installing the reducer shaft seal structure described in the first aspect above, comprising the following sequential steps: Clean the mounting surface of the shaft; install the O-ring in the annular groove on the inner wall of the bushing; fit the bushing into the designed position on the shaft; use fastening components to fix the bushing to the shaft; press the skeleton oil seal into the reducer housing so that its lip forms an interference fit with the outer circular surface of the bushing.

[0017] (III) Beneficial Effects Compared with the prior art, the present invention provides a reducer shaft seal structure and installation method, which has the following beneficial effects: The reducer shaft seal structure and installation method, by setting a replaceable bushing with a hardened wear-resistant layer as a sacrificial part, transfers the dynamic sealing interface from the expensive input shaft to the low-cost bushing, and combines O-ring static seal and skeleton oil seal dynamic seal to form a dual sealing system; with fastening components with anti-loosening structure, it can realize that only the bushing needs to be replaced when the seal fails, without repairing or replacing the entire shaft, and at the same time significantly improves the service life and operational reliability of the sealing system under heavy load vibration conditions. Attached Figure Description

[0018] Figure 1 This is an overall structural appearance diagram of the present invention; Figure 2 This is a schematic diagram of the bushing structure in this invention; Figure 3 This is a schematic diagram of the structure of the bushing and fastening assembly in this invention; Figure 4 This is a schematic diagram of the fastening assembly in this invention; Figure 5 This is a schematic diagram of the end face structure of the first setter and the second setter in this invention.

[0019] In the diagram: 1. Shaft; 2. Bushing; 3. Oil seal; 4. Fastening assembly; 5. O-ring; 6. Elastic washer; 201. Annular groove; 202. Threaded hole; 401. First set screw; 402. Internal threaded hole; 403. Second set screw; 404. Snap ball. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0021] Please see Figure 1-4 The first embodiment of the present invention provides a gearbox shaft seal structure, comprising: A replaceable bushing 2 is fitted onto the outside of the shaft 1, and its inner wall has multiple annular grooves 201; an O-ring 5 is provided in the annular grooves 201 to achieve a static seal between the bushing 2 and the shaft 1; a skeleton oil seal 3 is press-fitted into the reducer housing, and its lip is interference-fitted with the outer circular surface of the bushing 2 to form a dynamic sealing interface; and a fastening assembly 4 for detachably fixing the bushing 2 to the shaft 1; the bushing 2 has at least two threaded holes 202 radially provided for assembling the fastening assembly 4; Among them, bushing 2 is an independent wear-resistant sacrificial component. Its outer circular surface is provided with a wear-resistant layer that has been hardened, so that only bushing 2 needs to be replaced instead of shaft 1 when the seal fails, thereby achieving rapid repair and significantly reducing maintenance costs.

[0022] In this embodiment, the fastening assembly 4 includes a first set screw 401 that mates with the threaded hole 202. An elastic washer 6 is provided between the end of the first set screw 401 and the surface of the shaft 1. The first set screw 401 has an internal threaded hole 402 along its axial direction and is equipped with an anti-loosening structure.

[0023] It should be noted that the elastic gasket 6 is preferably made of nitrile rubber. This material has good oil resistance, elastic recovery performance and moderate compression set characteristics, which can continuously provide stable elastic preload under long-term vibration conditions, effectively buffer impact, and adapt to dimensional fluctuations between the bushing 2 and the shaft 1, thereby further enhancing the reliability of the anti-loosening structure.

[0024] In this embodiment, the anti-loosening structure includes a second set screw 403 that mates with the internal threaded hole 402, and at least two radially movable retaining beads 404 disposed inside the first set screw 401; the inner wall of the threaded hole 202 is provided with an annular retaining groove 203 at a corresponding position; when the second set screw 403 is screwed in, its end pushes the retaining beads 404 to move radially outward and engage with the retaining groove 203.

[0025] It should be noted that the retaining ball 404 is made of GCr15 bearing steel with a hardness of HRC60-62. The depth of the retaining groove 203 is designed to be 1.2-1.5mm, and it adopts a rounded transition structure. When the second set screw 403 is screwed in, its end contacts the retaining ball 404, generating a radial force that pushes the retaining ball 404 outward until it is fully engaged with the retaining groove 203, forming a mechanical interlock and effectively preventing loosening under vibration.

[0026] It should be further noted that the end of the second set screw 403 is preferably tapered.

[0027] It should also be noted that the fastening assembly 4 has a unique dual anti-loosening mechanism. Its anti-loosening principle is as follows: when the second set screw 403 is screwed in and pushes the retaining bead 404 to expand radially, the retaining bead 404 forms a mechanical interlock with the annular groove 203 on the inner wall of the first set screw 401, effectively locking the first set screw 401 and preventing it from rotating and loosening. At this time, the weak point of the entire anti-loosening system is transferred to the second set screw 403. Even if the second set screw 403 rotates, because the first set screw 401 remains locked, its loosening process has a significant delay characteristic, providing sufficient early warning time for equipment maintenance. Potential risks can be detected and addressed in advance, thereby effectively preventing sealing failure accidents caused by fastener loosening.

[0028] In this embodiment, the first set screw 401 and the second set screw 403 have the same thread direction; and when the first set screw 401 and the second set screw 403 are installed in place, their top ends do not protrude from the outer circle surface of the bushing 2.

[0029] It should be noted that the use of the same thread direction design facilitates assembly using standard tools, and the structural feature that the set screw does not protrude from the outer surface of the bushing 2 ensures that the skeleton oil seal 3 will not be scratched by the end of the set screw during assembly and operation, and also helps to maintain uniform contact between the oil seal lip and the outer circle of the bushing 2.

[0030] To facilitate the assembly of the first set screw 401 and the second set screw 403, such as Figure 5 As shown, the first set screw 401 has a slotted groove at its end, while the second set screw 403 has an internal hexagonal groove at its end. This differentiated groove design allows for installation using either a standard flathead screwdriver or an internal hexagonal wrench, effectively avoiding tool interference and improving assembly efficiency and convenience.

[0031] In this embodiment, there are three threaded holes 202 and three matching fastening components 4, which are evenly distributed along the circumference of the bushing 2.

[0032] It should be noted that the design of three fastening points evenly distributed at 120° circumference forms a stable three-point support system, which can effectively prevent the bushing 2 from tilting during operation, ensure uniform contact between the lip of the skeleton oil seal 3 and the outer surface of the bushing 2, and avoid early failure caused by local wear.

[0033] In this embodiment, the hardened layer on the outer circular surface of the bushing 2 has a hardness of not less than HRC55 and a roughness Ra of not more than 0.4μm.

[0034] It should be noted that by controlling the hardness and surface roughness of the hardened layer, the coefficient of friction is reduced while ensuring wear resistance, thereby reducing the wear of the lip of the skeleton oil seal and extending the service life of the sealing system.

[0035] In this embodiment, the O-ring 5 is made of fluororubber; the ratio of the depth of the annular groove 201 to the cross-sectional diameter of the O-ring 5 is 0.85:1.

[0036] It should be noted that fluororubber materials have excellent oil resistance, high temperature resistance, and aging resistance, and are suitable for operating temperature ranges from -20℃ to 200℃. The specific proportional relationship between the depth of the annular groove 201 and the cross-sectional diameter of the O-ring 5 ensures that the O-ring 5 achieves an optimal compression ratio of 15%-20%, which guarantees the reliability of the static seal while avoiding premature failure caused by over-compression.

[0037] In this embodiment, the wall thickness of bushing 2 is not less than 1 / 10 of the shaft diameter of shaft 1, and not less than 5mm.

[0038] It should be noted that this wall thickness design specification ensures that bushing 2 has sufficient rigidity and strength to withstand various loads during operation without deformation. For a typical application with a shaft diameter of 50mm, the wall thickness of bushing 2 is designed to be 5mm, which satisfies the rigidity requirements while controlling the overall weight and material cost.

[0039] A second aspect of the present invention provides a speed reducer in which at least one of its input shaft and output shaft employs the sealing structure described in the first embodiment.

[0040] It should be noted that this reducer is particularly suitable for heavy-duty vibration conditions such as mining crushers and cement mixers. When both the input and output shafts adopt this sealing structure, a complete sealing protection system can be formed, which significantly improves the reliability and service life of the whole machine.

[0041] The third embodiment of the present invention provides an installation method for the reducer shaft seal structure described in the first embodiment above, comprising the following sequential steps: Clean the mounting surface of shaft 1; install O-ring 5 in the annular groove 201 on the inner wall of bushing 2; fit bushing 2 into the designed position of shaft 1; use fastening assembly 4 to fix bushing 2 to shaft 1; press the skeleton oil seal 3 into the reducer housing so that its lip forms an interference fit with the outer circular surface of bushing 2.

[0042] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A reducer shaft seal structure, characterized in that, include: Replaceable bushing (2) is fitted on the outside of shaft (1), and its inner wall has multiple annular grooves (201). The O-ring (5) disposed in the annular groove (201) is used to achieve a static seal between the bushing (2) and the shaft (1); The skeleton oil seal (3) is press-fitted into the reducer housing, and its lip is interference-fitted with the outer circular surface of the bushing (2) to form a dynamic sealing interface; And a fastening assembly (4) for detachably fixing the bushing (2) to the shaft (1). The bushing (2) has at least two threaded holes (202) in the radial direction for assembling the fastening assembly (4). The bushing (2) is an independent wear-resistant sacrificial component. Its outer circular surface is provided with a wear-resistant layer that has been hardened, so that when the seal fails, only the bushing (2) needs to be replaced instead of the shaft (1), thereby achieving rapid repair and significantly reducing maintenance costs.

2. The reducer shaft seal structure according to claim 1, characterized in that: The fastening assembly (4) includes a first set screw (401) that mates with the threaded hole (202), and an elastic washer (6) is provided between the end of the first set screw (401) and the surface of the shaft (1). The first set screw (401) has an internal threaded hole (402) along its axial direction and is equipped with an anti-loosening structure.

3. The gearbox shaft seal structure according to claim 2, characterized in that: The anti-loosening structure includes a second set screw (403) that mates with the internal threaded hole (402), and at least two radially movable retaining balls (404) disposed inside the first set screw (401). The inner wall of the threaded hole (202) is provided with an annular groove (203) at the corresponding position. When the second set screw (403) is screwed in, its end pushes the retaining bead (404) to move radially outward and engages with the retaining groove (203).

4. The reducer shaft seal structure according to claim 3, characterized in that: The first set screw (401) and the second set screw (403) have the same thread direction; Furthermore, when the first set screw (401) and the second set screw (403) are installed in place, their top ends do not protrude from the outer circular surface of the bushing (2).

5. The reducer shaft seal structure according to claim 1, characterized in that: The number of the threaded holes (202) and the matching fastening components (4) is three, and they are evenly distributed along the circumference of the bushing (2).

6. The reducer shaft seal structure according to claim 1, characterized in that: The hardened layer on the outer circular surface of the bushing (2) has a hardness of not less than HRC55 and a roughness Ra of not more than 0.4μm.

7. The reducer shaft seal structure according to claim 1, characterized in that: The O-ring (5) is made of fluororubber; the ratio of the depth of the annular groove (201) to the cross-sectional diameter of the O-ring (5) is 0.85:

1.

8. The reducer shaft seal structure according to claim 1, characterized in that: The wall thickness of the bushing (2) is not less than 1 / 10 of the shaft diameter of the shaft (1) and not less than 5 mm.

9. A speed reducer, characterized in that, At least one of its input shaft and output shaft employs a sealing structure as described in any one of claims 1 to 8.

10. A method for installing a reducer shaft seal structure as described in any one of claims 1 to 8, characterized in that, Includes the following sequential steps: Clean the mounting surface of the shaft (1); install the O-ring (5) in the annular groove (201) on the inner wall of the bushing (2); fit the bushing (2) into the designed position of the shaft (1); use the fastening assembly (4) to fix the bushing (2) to the shaft (1); press the skeleton oil seal (3) into the reducer housing so that its lip forms an interference fit with the outer circular surface of the bushing (2).

Images