A plug-in shaft tail sealing device and sealing method

Abstract

The application belongs to the technical field of dynamic sealing structure design, and particularly relates to a plug-in type shaft tail sealing device and a sealing method; wherein the sealing device comprises a sleeve, a wave ring, a movable ring, a fixed ring and a threaded retainer, and the wave ring, the movable ring, the fixed ring and the threaded retainer are sequentially installed in the sleeve; the sleeve is a hollow structure, one end of the sleeve is closed, the other end of the sleeve is open, a ring-shaped boss for accommodating the fixed ring is arranged in the center of the sleeve, the wave ring is arranged between the fixed ring and the bottom of the sleeve, the threaded retainer is installed at the end of the open end of the sleeve, and the threaded retainer and the fixed ring jointly constrain the spatial position of the movable ring, so as to ensure that the movable ring, the fixed ring and the ring-shaped boss are on the same axis. The shaft tail sealing device of the aviation hydraulic pump is a replaceable unit of the aviation hydraulic pump, when the product has a shaft tail oil leakage fault in an external factory, the product can be directly replaced, and the maintenance cycle and cost of the product are greatly shortened.

Description

Technical Field

[0001] This invention belongs to the field of dynamic sealing structure design technology, and specifically relates to a cartridge-type shaft tail sealing device and sealing method. Background Technology

[0002] Because aircraft hydraulic systems have long return oil lines, which are typically equipped with oil filters and cooling devices, the pressure inside the housing of aviation hydraulic pumps is high. Therefore, the tail seal of aviation hydraulic pumps often employs a combination of mechanical and static seals to prevent oil leakage from the housing. Currently, the tail seal structure of aviation hydraulic pumps uses a split-installation design. This design means that the sealing performance of the tail seal can only be verified during testing of the aviation hydraulic pump, and cannot be tested and evaluated independently. Consequently, when the tail seal leaks, the entire product needs to be disassembled for repair. This significantly increases the workload and repair time for operators. Furthermore, disassembly and reassembly can damage the assembly relationships of other components in the hydraulic pump, easily leading to scratches and damage, reducing the overall reliability and lifespan of the pump. Additionally, when current aviation hydraulic pumps experience excessive tail seal leakage, the product must be returned to the manufacturer for disassembly and replacement of the damaged unit, greatly increasing the repair cycle and maintenance costs.

[0003] Currently, conventional shaft tail seal structures, such as the one disclosed in patent CN217713633U, which improves the maintainability of aviation hydraulic pumps, include a mounting base with a front bearing located in the inner hole of the mounting base, a rear cover on the rear side of the mounting base, and a shaft tail seal assembly located between the front bearing and the rear cover. The shaft tail seal structure adopts a split design; the front bearing is directly mounted on the inner hole of the mounting base, and the shaft tail seal assembly is installed between the rear cover and the front bearing. When disassembling and inspecting the shaft tail seal assembly or replacing components, only the rear cover needs to be disassembled, eliminating the need to disassemble other unrelated parts, thus greatly facilitating the disassembly, assembly, and maintenance of the shaft tail seal assembly. In the shaft tail seal structure proposed in this patent, the shaft tail seal assembly is installed between the rear cover and the front bearing. The rotating ring is positioned by both the front bearing and a bushing. The bushing and the inner shaft have an interference fit. Under the preload of the wave ring, the washer fits against the rotating ring. The preload of the wave ring can be adjusted by adjusting the thickness of the washer, thereby adjusting the specific pressure and specific work of the rotating and fixed ring friction pair. Because the inner shaft of the bushing is an interference fit, it is not easy to disassemble; and the moving ring and the fixed ring are detachable, the dimensions of multiple parts such as the back cover, mounting base, and inner shaft need to be measured to calculate the compression of the wave ring and then select the appropriate washer thickness. Summary of the Invention

[0004] 1. Technical problems to be solved

[0005] The existing tail seal structure of aviation hydraulic pumps adopts a split installation design. This design means that the sealing performance of the tail seal structure can only be verified during aviation hydraulic pump testing, and it is impossible to test and evaluate the sealing performance of the tail seal structure independently. Furthermore, when troubleshooting or repairing products with tail oil leakage faults, field replacement is not possible; the product must be returned to the manufacturer for repair. Moreover, repair requires complete disassembly of the product for inspection, significantly increasing the maintenance cycle and cost, and reducing the product's reliability and lifespan.

[0006] 2. Technical Solution

[0007] The technical solution adopted in this invention is as follows: This invention proposes a plug-in type shaft tail sealing device, which includes: a sleeve, a corrugated ring, a rotating ring, a fixed ring, and a threaded retaining ring. The corrugated ring, rotating ring, fixed ring, and threaded retaining ring are sequentially installed inside the sleeve. The sleeve has a hollow structure, with one end closed and the other end open. A ring-shaped boss for mounting the fixed ring is provided at the center of the sleeve. A corrugated ring is provided between the fixed ring and the bottom of the sleeve. The threaded retaining ring is installed at the open end of the sleeve. The threaded retaining ring and the fixed ring together constrain the spatial position of the rotating ring to ensure that the rotating ring, fixed ring, and ring-shaped boss are on the same axis.

[0008] Furthermore, a sealing ring is provided between the fixed ring and the annular boss.

[0009] Furthermore, a washer is provided between the wave ring and the bottom of the sleeve to adjust the preload of the wave ring.

[0010] Furthermore, an annular groove is provided on the rotating ring at the contact position with the threaded retaining ring to limit the radial displacement of the rotating ring.

[0011] Furthermore, the inner ring of the moving ring is provided with a groove, which matches the position of the cut on the inner shaft, so that the moving ring rotates synchronously with the rotation of the inner shaft.

[0012] Furthermore, several through holes are provided on the outer wall of the sleeve at the position opposite to the moving ring, and multiple oil return holes are also provided near the bottom of the sleeve; external oil enters the inner cavity of the sleeve through the through holes, and the oil is driven to rotate in the inner cavity of the sleeve by the high-speed moving ring of the inner shaft and then thrown out through the oil return holes.

[0013] In another aspect, the present invention also proposes a cartridge-type shaft tail seal method, in which the shaft tail seal device is installed at the shaft tail end of a hydraulic pump or test bench, and the shaft tail seal device is axially positioned by a retaining ring. At the same time, the groove of the moving ring is connected to the inner shaft cut position. Due to the axial limiting effect of the inner shaft cut position, the moving ring is disengaged from the threaded retaining ring, reaching the pre-compression position, and the shaft tail seal device is installed.

[0014] When the hydraulic pump is working, the oil in the housing cavity enters the inner cavity of the sleeve through the bearing. The sleeve and the mounting seat are sealed by sealing ring a, the sleeve and the fixed ring are sealed by sealing ring b, and the inner shaft and the moving ring are sealed by sealing ring c. At the same time, the inner shaft drives the moving ring to rotate synchronously. The preload of the corrugated ring makes the moving ring and the fixed ring fit together, realizing the dynamic sealing of the oil in the inner cavity of the sleeve. Meanwhile, an oil return channel is provided to connect to the oil return hole of the shaft tail sealing device, so that the oil in the housing cavity and the inner cavity of the sleeve can circulate during operation, thereby carrying away the heat generated by the friction between the moving and fixed rings.

[0015] 3. Beneficial technical effects

[0016] This invention employs an integrated design approach, allowing for separate sealing and reliability tests on the tail seal device, thereby improving the reliability and maintainability of the aviation hydraulic pump. Furthermore, by treating the tail seal device as a replaceable unit of the aviation hydraulic pump, it can be directly replaced when tail oil leakage occurs at an external manufacturer, significantly shortening the product's maintenance cycle and reducing costs. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and examples:

[0018] Figure 1 This is a schematic diagram of the structure of the present invention; 1-sealing ring a; 2-sealing ring b; 3-sealing ring c; 4-wave ring; 5-adjusting washer; 6-fixed ring; 7-moving ring; 8-sleeve; 9-threaded retaining ring.

[0019] Figure 2 This is an assembly diagram of the present invention; 10-clamp ring; 11-mounting base; 12-bearing; 13-inner shaft. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings. (See attached drawings for details.) Figure 1 As shown, Figure 1 The assembly diagram of the present invention shown illustrates that the shaft tail sealing device mainly consists of sealing ring a1, sealing ring b2, sealing ring c3, ​​corrugated ring 4, adjusting washer 5, fixed ring 6, rotating ring 7, sleeve 8, and threaded retaining ring 9. The rotating ring 7 has a groove that engages with a notch on the inner shaft, allowing the rotating ring to rotate with the inner shaft. The sleeve 8 has threads that connect to the threaded retaining ring 9, thereby limiting the axial displacement of internal components such as the fixed ring 6, rotating ring 7, and corrugated ring 4. A disassembly hole is also provided on the end face for easy disassembly of the entire shaft tail sealing device. An annular groove is provided on the rotating ring 7 at the contact point with the threaded retaining ring 9 to limit the radial displacement of the rotating ring. The preload of the corrugated ring 4 installed inside the sleeve 8 ensures that the fixed ring 6 and rotating ring 7 are in close contact. By changing the thickness of the adjusting washer 5, the contact stress between the rotating ring 7 and the fixed ring 6 can be adjusted, thereby adjusting the sealing performance of the dynamic seal.

[0021] like Figure 2 The assembly diagram of the present invention is shown. When the shaft tail sealing device is installed on a hydraulic pump or test bench, the shaft tail sealing device is axially positioned by the retaining ring 10. At the same time, the groove of the moving ring is connected to the inner shaft cut position. Due to the axial limiting effect of the inner shaft 13 cut position, the moving ring is disengaged from the threaded retaining ring and reaches the pre-compression position, and the shaft tail sealing device is installed.

[0022] When the hydraulic pump is working, the oil in the housing cavity enters the first oil chamber (i.e., the inner cavity of the sleeve) through the bearing 12. The sleeve and the mounting seat are sealed by sealing ring a, the sleeve and the fixed ring are sealed by sealing ring b, and the inner shaft and the moving ring are sealed by sealing ring c. At the same time, the inner shaft drives the moving ring to rotate synchronously, and the preload of the corrugated ring makes the moving ring and the fixed ring fit together, thus achieving a dynamic seal for the oil in the first oil chamber (i.e., the inner cavity of the sleeve). Meanwhile, a return oil passage is provided on the external mounting seat 11 to connect to the pump cavity, so that the oil in the housing cavity and the first oil chamber circulates during operation, thereby carrying away the heat generated by the friction between the moving and fixed rings and reducing the problem of dynamic and static seal failure caused by the high temperature generated by the shaft tail sealing device during long-term operation.

[0023] When an oil leak occurs at the shaft tail, simply remove the retaining ring and take out the shaft tail seal through the disassembly hole on the sleeve for inspection or replacement.

[0024] The tail seal device proposed in this invention eliminates the need to install it on the aviation hydraulic pump when verifying its sealing performance and reliability. Instead, it can be tested on a suitable test bench. A qualified tail seal device can be directly installed in the corresponding product without disassembling other unrelated components, thus significantly improving the reliability and maintainability of the aviation hydraulic pump. Compared to traditional tail seal structures, this invention uses an integrated structure. Only the depth of the installation area needs to be measured to calculate the required compression of the corrugated ring. Therefore, limiting the product's depth during the design phase allows for use as a replaceable unit, reducing the difficulty of the actual assembly process and improving maintainability.

[0025] The present invention has been described in detail above with reference to the accompanying drawings and specific embodiments. It should be noted that some (but not all) of the disclosed examples are shown in the drawings. In fact, many different examples can be described, and these examples should not be construed as limited to those set forth herein. Rather, these examples are described to further highlight the positive effects of the present invention, and all aspects not detailed herein are considered to be well-known or conventional techniques in the art.

Claims

1. A canned shaft seal apparatus, characterized by, The sealing device comprises a sleeve, a wave ring, a movable ring, a fixed ring and a threaded retainer ring, which are sequentially installed in the sleeve; the sleeve is a hollow structure with one end closed and the other end open, and a ring-shaped boss for accommodating the fixed ring is arranged in the center of the sleeve; the wave ring is arranged between the fixed ring and the bottom of the sleeve; the threaded retainer ring is installed at the end of the open end of the sleeve; the threaded retainer ring and the fixed ring jointly constrain the spatial position of the movable ring to ensure that the movable ring, the fixed ring and the ring-shaped boss are on the same axis; A plurality of through holes are formed in the position of the outer wall of the sleeve opposite to the movable ring, and a plurality of oil return holes are also formed near the bottom of the sleeve; external oil enters the inner cavity of the sleeve through the through holes, and is thrown out of the oil return holes after rotating in the inner cavity of the sleeve under the driving of the high-speed movable ring; a groove is arranged on the inner ring of the movable ring, and the groove cooperates with the notch position on the inner shaft to enable the movable ring to rotate synchronously with the inner shaft; The sealing device is installed at the tail end of the shaft of a hydraulic pump or a test bench, and the shaft tail sealing device is axially positioned by a clamping ring, and at the same time, the groove of the movable ring is connected with the notch position of the inner shaft; due to the axial positioning effect of the notch position of the inner shaft, the movable ring is separated from the threaded retainer ring to reach the pre-compression position, and the installation of the shaft tail sealing device is completed; When the hydraulic pump is working, the oil in the cavity of the shell enters the inner cavity of the sleeve through the bearing, the sleeve and the mounting seat are sealed by a sealing ring a, the sleeve and the fixed ring are sealed by a sealing ring b, and the inner shaft and the movable ring are sealed by a sealing ring c; at the same time, the inner shaft drives the movable ring to rotate synchronously, the wave ring pre-tightening force makes the movable ring and the fixed ring fit together to realize dynamic sealing of the oil in the inner cavity of the sleeve; at the same time, the oil return oil channel is connected with the oil return holes of the shaft tail sealing device to make the oil in the cavity of the shell and the inner cavity of the sleeve circulate during work, thereby taking away the heat generated by the friction between the movable ring and the fixed ring.

2. The packaged shaft seal assembly of claim 1 wherein, A circular groove is arranged on the movable ring at the position where the movable ring contacts the threaded retainer ring to limit the radial displacement of the movable ring.

3. The canned shaft seal assembly of claim 1 wherein, A gasket is further arranged between the wave ring and the bottom of the sleeve to adjust the pre-tightening force of the wave ring.

4. The canned shaft seal assembly of claim 1 wherein, A dismounting hole is formed at the end of the shaft tail sealing device.

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