An expansion fitting and method of use

Abstract

The application discloses a kind of expansion installation tool and method, belong to tool fixture technical field, to solve the installation mode of the driving cone and low pressure compressor rotor through spline and double stop port interference coupling when existing bevel gear simulation loading test, it is difficult to disassemble after assembly, the installation tool of the application includes locking assembly, mandrel, thrust pad, expansion ring and adjusting pad, one end of mandrel is circumferentially provided with annular limiting protrusion, expansion ring is sleeved on the outer circular surface of mandrel, and adjusting pad is provided between one end of expansion ring and limiting protrusion, thrust pad is provided on the other end of expansion ring, and thrust pad is sleeved on the outer circular surface of mandrel, locking assembly is provided on the end of thrust pad away from expansion ring, locking assembly is sleeved on mandrel, and the other end of thrust pad is tightly attached with expansion ring by locking assembly. The application is mainly used for the installation tool of driving cone and low pressure compressor rotor during bevel gear simulation loading test.

Description

Technical Field

[0001] This invention belongs to the field of tooling and fixture technology, specifically relating to an expansion and tightening installation tool and its usage method. Background Technology

[0002] The gas turbine features a central drive mechanism. One end of the central drive mechanism is connected to the low-pressure compressor rotor, and the other end is connected to the lower transmission box. During unit operation, the central drive mechanism drives the lower transmission box, which in turn drives the fuel pump and lubrication components. During startup, the central drive mechanism, as part of the transmission circuit, drives the compressor.

[0003] Before assembling the entire machine, a full-load test must be performed on the bevel gears of the central transmission mechanism. The central transmission mechanism consists of spiral bevel gears with a shaft angle of 90° and bearings, etc. The driving bevel gear is installed with the low-pressure compressor rotor via a spline and double-stop interference fit, making disassembly difficult after assembly. The driven bevel gear is connected to the lower transmission box via a splined rod. Therefore, when conducting simulated load tests on the bevel gears, the installation method of the test drive shaft and the driving bevel gear should be considered to ensure easy disassembly, no damage to parts, and the ability to transmit torque. Summary of the Invention

[0004] This invention addresses the problem of difficulty in disassembling a bevel gear after assembly due to the existing installation method of interlocking the active cone with the low-pressure compressor rotor via splines and double stop ports during simulated loading tests. It provides a tightening installation fixture and its usage method.

[0005] An expansion and tightening installation fixture includes a locking assembly, a mandrel, a thrust pad, an expansion ring, and an adjusting pad. One end of the mandrel has an annular limiting protrusion along its circumference, and the annular limiting protrusion is integrally formed with the mandrel. The expansion ring is sleeved on the outer circumferential surface of the mandrel, and an adjusting pad is provided between one end of the expansion ring and the limiting protrusion. The adjusting pad is sleeved on the outer circumferential surface of the mandrel. The thrust pad is provided on the other end of the expansion ring and is sleeved on the outer circumferential surface of the mandrel. A locking assembly is provided on the end of the thrust pad away from the expansion ring. The locking assembly is sleeved on the mandrel, and the thrust pad is tightly fitted to the other end of the expansion ring through the locking assembly.

[0006] Furthermore, the locking assembly includes a retaining ring, a thrust nut, and multiple bolts. The retaining ring has multiple positioning holes machined equidistantly along the circumferential direction on its end face. The thrust nut has multiple threaded holes machined equidistantly along the circumferential direction on its end face, and each threaded hole is coaxially corresponding to a positioning hole. The thrust nut is sleeved on the end of the mandrel away from the adjusting pad, and the thrust nut is detachably connected to the mandrel by threads. The retaining ring is set on the end of the thrust nut away from the thrust pad, and the retaining ring is limited by a positioning groove located on the inner wall of the middle hole of the test drive shaft. The threaded section of each bolt passes through a positioning hole in sequence and is set in a threaded hole, and each bolt is threadedly connected to the thrust nut. The end of each bolt contacts the thrust pad.

[0007] Furthermore, the mandrel is a stepped shaft, and from left to right, the mandrel is coaxially provided with a tapered mating shaft section, a transition shaft section, and a threaded shaft section. An annular limiting protrusion is sleeved on the outer circular surface of the large end of the tapered mating shaft section. The transition shaft section is set on the small end of the tapered mating shaft section, and one end of the transition shaft section is integrally formed with the small end of the tapered mating shaft section. The connection between the transition shaft section and the tapered mating shaft section forms a first positioning step. The threaded shaft section is set on the other end of the transition shaft section, and one end of the threaded shaft section is integrally formed with the other end of the transition shaft section. The connection between the threaded shaft section and the transition section forms a second positioning step. A thrust nut positioning groove is machined circumferentially at the root of the second positioning step.

[0008] Furthermore, a positioning tapered hole is machined along the axial direction of the mandrel at the center of the end face of the large opening end of the tapered mating shaft section. An oil guide blind hole is machined along the axial direction of the mandrel at the center of the end face of the threaded shaft section away from the transition shaft section. Multiple branch flow hole groups are machined at equal intervals along the extension direction of the oil guide blind hole on the inner wall of the oil guide blind hole. Each branch flow hole group includes multiple branch flow holes. The multiple branch flow holes are distributed at equal intervals along the circumferential direction on the inner wall of the oil guide blind hole. One end of each branch flow hole is connected to the oil guide blind hole, and the other end of each branch flow hole is connected to the tapered outer circular surface of the tapered mating shaft section. An internal thread is machined on the inner wall of the opening end of the oil guide blind hole to mate with the external oil guide pipe connection part.

[0009] Furthermore, the inner ring surface of the expansion ring is a conical surface, the outer ring surface of the expansion ring is a cylindrical surface, and the inner ring surface of the expansion ring is fitted with the outer cylindrical surface of the conical surface mating shaft section, and the outer ring surface of the expansion ring is fitted with the inner hole surface of the test drive shaft.

[0010] A method for using an expansion clamping installation fixture, the method being implemented through the following steps:

[0011] Step 1: When installing the expansion and tightening fixture, first insert the mandrel into the middle inner hole of the test drive shaft, with the conical surface of the mandrel fitting close to the bottom of the middle inner hole at the large end of the shaft section.

[0012] Step 2: Insert the adjusting shim and expansion ring into the test drive shaft, and ensure that the inner ring surface of the expansion ring mates with the outer ring surface of the mandrel;

[0013] Step 3: Install the propulsion assembly on the threaded section of the mandrel, and use the propulsion assembly to make the expansion ring and the mandrel move towards each other along the conical surface, so that the mandrel radially tightens the expansion ring;

[0014] Step 4: After the expansion ring has expanded radially, remove the push assembly from the threaded section of the mandrel, and at the same time tighten the locking assembly onto the threaded section of the mandrel, and use the locking assembly to axially lock the expansion ring.

[0015] Step 5: When it is necessary to disassemble the expansion installation fixture, first remove the locking assembly from the mandrel, and at the same time connect the external hydraulic oil pipe to the oil guide blind hole in the middle of the mandrel;

[0016] Step 6: After the external hydraulic oil pipe is connected to the mandrel, use the external hydraulic oil pipe to inject oil into the mandrel. The hydraulic oil smoke flows into the gap between the mandrel and the expansion ring through the diversion hole, causing the expansion ring and the mandrel to move in opposite directions and to separate the expansion ring and the mandrel.

[0017] Step 7: With the expansion ring and mandrel separated, first remove the expansion ring from the mandrel, and then remove the mandrel from the central inner hole on the test drive shaft;

[0018] Further, the propulsion assembly in step three includes a propulsion sleeve, a first O-ring, a propulsion cylinder rod, and a second O-ring. The propulsion cylinder rod is a two-stage stepped shaft structure. A threaded hole is machined on the end face of the small-diameter end of the propulsion cylinder rod to mate with the threaded shaft section on the mandrel. A positioning step is provided at the end of the threaded hole. A first O-ring groove is machined on the outer circumference of the large-diameter shaft section of the propulsion cylinder rod, and a second O-ring groove is machined on the outer circumference of the small-diameter shaft section of the propulsion cylinder rod. The propulsion sleeve is a second O-ring that mates with the propulsion cylinder rod. A stepped bushing is provided, with the outer sleeve of the pusher cylinder being fitted onto the pusher cylinder rod. O-rings No. 1 and No. 2 are positioned between the outer sleeve and the pusher cylinder rod, with O-ring No. 1 positioned in the O-ring groove and O-ring No. 2 positioned in the O-ring groove. An oil inlet hole is machined on the end face of the large end of the pusher cylinder rod, and an internal thread is machined on the inner wall of the oil inlet hole to mate with the connection of the external oil guide pipe. The end of the oil inlet hole is connected to the cavity formed between the step in the pusher cylinder rod and the step in the pusher outer sleeve.

[0019] Furthermore, the specific operation of using the propulsion assembly to cause the expansion ring and the mandrel to move in opposite directions along the conical surface in step three is as follows:

[0020] Step 31: Fit the push cylinder rod onto the threaded section of the mandrel, and thread the push cylinder rod and mandrel together until the end of the mandrel contacts the positioning step on the push cylinder rod, confirming that the push cylinder rod and mandrel are installed in place;

[0021] Step 32: Install the external hydraulic oil pipe in the oil inlet hole on the push cylinder rod, and fix the external hydraulic oil pipe to the push cylinder rod by thread;

[0022] Step 33: Under the premise of ensuring that the external hydraulic oil pipe is fixedly connected to the push cylinder rod, oil is injected into the gap between the push cylinder rod and the push sleeve through the external hydraulic oil pipe, so that the push sleeve and the push cylinder rod produce opposite displacements. The thrust of the push sleeve acts on the expansion ring through the thrust pad, and the tension of the push cylinder rod acts directly on the spindle. Through the opposite displacement between the push sleeve and the push cylinder rod, the spindle and the expansion ring produce opposite displacements along the conical surface, thereby putting the spindle and the expansion ring in a tightened state.

[0023] Furthermore, the specific operation of fitting the locking assembly onto the transition section of the mandrel in step four is as follows:

[0024] Step 41: First, install the thrust nut onto the threaded section of the mandrel via a threaded connection;

[0025] Step 42: Set the retaining ring for the hole on the end of the multiple thrust nuts away from the thrust pad, and limit it through the positioning groove located on the inner wall of the test drive shaft;

[0026] Step 43: Pass the threaded section of each bolt through a positioning hole on the retaining ring and place it in a threaded hole on the thrust nut, and each bolt is threadedly connected to the corresponding thrust nut;

[0027] Step 44: Make the end of each bolt contact the thrust pad, and squeeze the thrust pad and expansion ring by tightening the bolts, thereby limiting the axial displacement of the expansion ring.

[0028] The beneficial effects of this application compared to the prior art are:

[0029] This application proposes a tightening installation fixture that achieves radial tightening through the conical fit between the mandrel and the expansion ring, and adjusts the axial clearance by adjusting the thickness of the shim. The tightening of the expansion ring compresses the test drive shaft, bringing it into close contact with the drive bevel gear, thus achieving the purpose of mounting the test drive shaft onto the drive bevel gear. The tightening installation fixture provided by this application can provide tightening force to the test drive shaft, ensuring the installation stability between the test drive shaft and the drive bevel gear. Simultaneously, an oil guide blind hole is added inside the mandrel in the tightening installation fixture. By injecting hydraulic oil into the oil guide blind hole, the mandrel and the expansion ring are displaced in opposite directions with the assistance of the hydraulic oil, thereby separating the expansion ring and the mandrel. Compared with the traditional installation method using an interference fit connection, this improves the disassembly of the installation fixture, and the fixture does not damage the inner hole of the drive bevel gear during disassembly, making it convenient to use. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of this application;

[0031] Figure 2 This is a schematic diagram illustrating the state of expansion using the propulsion component in this application;

[0032] Figure 3 This is a schematic diagram of the state of this application during full-load testing;

[0033] The components in the diagram are: 1. retaining ring for hole; 2. mandrel; 3. bolt; 4. thrust nut; 5. thrust pad; 6. expansion ring; 7. adjusting pad; 8. push-in outer sleeve; 9. No. 1 O-ring; 10. push-in cylinder rod; 11. No. 2 O-ring; 12. test drive shaft; 13. driving bevel gear; 14. tensioning fixture; 15. driven bevel gear; and 16. spline rod. Detailed Implementation

[0034] Specific implementation method one: Combining Figures 1 to 3 This embodiment describes a tightening installation fixture, which includes a locking assembly, a mandrel 2, a thrust pad 5, an expansion ring 6, and an adjusting pad 7. One end of the mandrel 2 has an annular limiting protrusion along its circumference, and the annular limiting protrusion is integrally formed with the mandrel 2. The expansion ring 6 is sleeved on the outer circumferential surface of the mandrel 2, and an adjusting pad 7 is provided between one end of the expansion ring 6 and the limiting protrusion. The adjusting pad 7 is sleeved on the outer circumferential surface of the mandrel 2. The thrust pad 5 is provided on the other end of the expansion ring 6, and the thrust pad 5 is sleeved on the outer circumferential surface of the mandrel 2. A locking assembly is provided on the end of the thrust pad 5 away from the expansion ring 6, and the locking assembly is sleeved on the mandrel 2. The thrust pad 5 is tightly fitted to the other end of the expansion ring 6 through the locking assembly.

[0035] In this embodiment, an adjusting shim 7 is installed between the mandrel 2 and the expansion ring 6. The radial expansion of the tooling is adjusted by the thickness of the adjusting shim 7, thereby enabling the drive shaft of the test piece to reach a certain expansion amount. The axial compression between the mandrel 2 and the expansion ring 6 is achieved by hydraulic oil. The threaded end of the mandrel 2 is connected to the push cylinder rod 10. The outer side of the push cylinder rod 10 is fitted with the push sleeve 8. The cylinder rod and the sleeve are connected by an O-ring seal to form a closed sealing cavity. A threaded interface for hydraulic oil is left on the push cylinder rod. The push cylinder sleeve acts on the thrust pad, which is fitted on the mandrel, with its end face pressing against the end face of the expansion ring.

[0036] Specific Implementation Method Two: Combining Figures 1 to 3 This embodiment differs from specific embodiment one in that the locking assembly includes a retaining ring 1, a thrust nut 4, and multiple bolts 3. The retaining ring 1 has multiple circumferentially equidistant positioning holes machined on its end face. The thrust nut 4 has multiple circumferentially equidistant threaded holes machined on its end face, with each threaded hole coaxially corresponding to a positioning hole. The thrust nut 4 is fitted onto the end of the mandrel 2 away from the adjusting pad 7, and is threadedly detachably connected to the mandrel 2. The retaining ring 1 is positioned on the end of the thrust nut 4 away from the thrust pad 5, and is limited by a positioning groove located on the inner wall of the test drive shaft 12. The threaded section of each bolt 3 passes sequentially through a positioning hole and is positioned in a threaded hole, with each bolt 3 threadedly connected to the thrust nut 4. The end of each bolt 3 contacts the thrust pad 5. Other components and connection methods are the same as in specific embodiment one.

[0037] In this embodiment, the locking component is used to limit the expansion ring 6 after it is tightened, so as to ensure that the tooling does not loosen during the rotation of the shaft system. The thrust nut 4 is set between the spindle 2 and the expansion ring 6. The axial positioning of the thrust nut 4 is completed by the retaining ring 1 installed on the inner hole of the test shaft. The bolt 3 installed on the thrust nut 3 acts on the thrust pad 5 to prevent the tapered surface from loosening.

[0038] Specific implementation method three: Combining Figures 1 to 3This embodiment differs from Specific Embodiment 1 in that the mandrel 2 is a stepped shaft. From left to right, the mandrel 2 is coaxially provided with a tapered mating section, a transition section, and a threaded section. An annular limiting protrusion is fitted onto the outer circumference of the larger end of the tapered mating section. The transition section is located on the smaller end of the tapered mating section, and one end of the transition section is integrally formed with the smaller end of the tapered mating section. A first positioning step is formed at the connection between the transition section and the tapered mating section. The threaded section is located on the other end of the transition section, and one end of the threaded section is integrally formed with the other end of the transition section. A second positioning step is formed at the connection between the threaded section and the transition section. A thrust nut positioning groove is machined circumferentially at the root of the second positioning step. Other components and connection methods are the same as in Specific Embodiment 2.

[0039] Specific implementation method four: Combination Figures 1 to 3 This embodiment differs from Specific Embodiment 1 in that, in the mandrel 2, a positioning tapered hole is machined along the axial direction of the center of the large-mouth end face of the tapered mating shaft section. In the threaded shaft section of the mandrel 2, an oil guide blind hole is machined along the axial direction of the center of the end face away from the transition shaft section. Multiple branch flow hole groups are equidistantly machined on the inner wall of the oil guide blind hole along its extension direction. Each branch flow hole group includes multiple branch flow holes, which are equidistantly distributed circumferentially on the inner wall of the oil guide blind hole. One end of each branch flow hole communicates with the oil guide blind hole, and the other end communicates with the tapered outer surface of the tapered mating shaft section. An internal thread is machined on the inner wall of the open end of the oil guide blind hole to mate with the external oil guide pipe connection. Other components and connection methods are the same as in Specific Embodiment 3.

[0040] Specific Implementation Method Five: Combining Figures 1 to 3 This embodiment differs from Specific Embodiment One in that the inner ring surface of the expansion ring 6 is a conical surface, and the outer ring surface of the expansion ring 6 is a cylindrical surface. Furthermore, the inner ring surface of the expansion ring 6 mates with the outer cylindrical surface of the conical mating shaft section, and the outer ring surface of the expansion ring 6 mates with the inner bore surface of the test transmission shaft 12. Other components and connection methods are the same as in Specific Embodiment Four.

[0041] Specific Implementation Method Six: Combination Figures 1 to 3 This embodiment describes a method for using an expansion clamping installation fixture, which is achieved through the following steps:

[0042] Step 1: When installing the expansion and tightening installation fixture, first insert the mandrel 2 into the middle inner hole of the test drive shaft 12, with the conical surface of the mandrel 2 fitting the large end of the shaft section near the bottom of the middle inner hole;

[0043] Step 2: Insert the adjusting shim 7 and the expansion ring 6 into the test drive shaft 12, and make the inner ring surface of the expansion ring 6 match the outer ring surface of the mandrel 2;

[0044] Step 3: Install the propulsion assembly on the threaded section of the mandrel 2, and use the propulsion assembly to make the expansion ring 6 and the mandrel 2 move towards each other along the conical surface, so that the mandrel 2 radially tightens the expansion ring 6;

[0045] Step 4: After the expansion ring 6 has expanded radially, remove the push assembly from the threaded section of the mandrel 2, and at the same time tighten the locking assembly onto the threaded section of the mandrel 2, and use the locking assembly to axially lock the expansion ring 6.

[0046] Step 5: When it is necessary to disassemble the expansion installation fixture, first remove the locking assembly from the mandrel 2, and at the same time connect the external hydraulic oil pipe to the oil guide blind hole in the middle of the mandrel 2;

[0047] Step 6: After the external hydraulic oil pipe is connected to the mandrel 2, oil is injected into the mandrel 2 through the external hydraulic oil pipe. The hydraulic oil smoke flows into the gap between the mandrel 2 and the expansion ring 6 through the diversion hole, causing the expansion ring 6 and the mandrel 2 to move in opposite directions and to separate the expansion ring 6 and the mandrel 2.

[0048] Step 7: With the expansion ring 6 and the mandrel 2 separated, first remove the expansion ring 6 from the mandrel 2, and then remove the mandrel 2 from the central inner hole of the test drive shaft 12.

[0049] Specific implementation method seven: Combining Figures 1 to 3 This embodiment differs from specific embodiment six in that the propulsion assembly in step three includes a propulsion sleeve 8, a first O-ring 9, a propulsion cylinder rod 10, and a second O-ring 11. The propulsion cylinder rod 10 has a two-stage stepped shaft structure. A threaded hole is machined on the end face of the small-diameter end of the propulsion cylinder rod 10 to mate with the threaded shaft section on the mandrel 2. A positioning step is provided at the end of the threaded hole. A first O-ring groove is machined on the outer circumference of the large-diameter shaft section of the propulsion cylinder rod 10, and a second O-ring groove is machined on the outer circumference of the small-diameter shaft section of the propulsion cylinder rod 10. The propulsion sleeve 8 is designed to mate with the propulsion cylinder rod 2. A two-stage stepped bushing is fitted to the cylinder rod 10. An outer sleeve 8 is fitted onto the cylinder rod 10. A first O-ring 9 and a second O-ring 11 are positioned between the outer sleeve 8 and the cylinder rod 10. The first O-ring 9 is positioned in the first O-ring groove, and the second O-ring 11 is positioned in the second O-ring groove. An oil inlet hole is machined on the end face of the larger end of the cylinder rod 10. An internal thread is machined on the inner wall of the oil inlet hole to mate with the connection of the external oil guide pipe. The end of the oil inlet hole communicates with the cavity formed between the step in the cylinder rod 10 and the step in the outer sleeve 8. Other components and connections are the same as in specific embodiment six.

[0050] In this embodiment, the function of the propulsion component is to assist the expansion ring 6 and the spindle 2 in generating a counter-displacement along the working cone surface. Under the action of the counter-displacement, the expansion ring 6 and the spindle 2 are tightened, thereby enabling the test transmission shaft 12 and the drive bevel gear 13 to achieve the purpose of tightening.

[0051] Specific implementation method eight: Combination Figures 1 to 3 This embodiment differs from specific embodiment seven in that the specific operation of using the propulsion assembly to cause the expansion ring 6 and the mandrel 2 to move towards each other along the conical surface in step three is as follows:

[0052] Step 31: Fit the push cylinder rod 10 onto the threaded section of the mandrel 2, and thread the push cylinder rod 10 and the mandrel 2 together until the end of the mandrel 2 contacts the positioning step on the push cylinder rod 10, confirming that the push cylinder rod 10 and the mandrel 2 are installed in place;

[0053] Step 32: Install the external hydraulic oil pipe in the oil inlet hole on the push cylinder rod 10, and fix the external hydraulic oil pipe to the push cylinder rod 10 by thread;

[0054] Step 33: Under the premise of ensuring that the external hydraulic oil pipe is fixedly connected to the push cylinder rod 10, oil is injected into the gap formed between the push cylinder rod 10 and the push sleeve 8 through the external hydraulic oil pipe, so that the push sleeve 8 and the push cylinder rod 10 produce opposite displacements. The thrust of the push sleeve 8 acts on the expansion ring 6 through the thrust pad 5, and the tension of the push cylinder rod 10 acts directly on the spindle 2. Through the opposite displacement between the push sleeve 8 and the push cylinder rod 10, the spindle 2 and the expansion ring 6 produce opposite displacements along the conical surface, thereby putting the spindle 2 and the expansion ring 6 into a tightened state.

[0055] The other methods and steps are the same as those in Specific Implementation Method Six.

[0056] Specific Implementation Method Nine: Combining Figures 1 to 3 This embodiment differs from specific embodiment eight in that the specific operation of fitting the locking assembly onto the transition shaft section of the mandrel 2 in step four is as follows:

[0057] Step 41: First, install the thrust nut 4 onto the threaded section of the mandrel 2 via a threaded connection;

[0058] Step 42: Set the retaining ring 1 for the hole on the end of the multiple thrust nuts 4 away from the thrust pad 5, and limit it by the positioning groove on the inner wall of the test drive shaft 12 in the middle;

[0059] Step 43: Pass the threaded section of each bolt 3 through a positioning hole on the retaining ring 1 and set it in a threaded hole on the thrust nut 4, and each bolt 3 is threadedly connected to the corresponding thrust nut 4;

[0060] Step 44: Make the end of each bolt 3 contact the thrust pad 5, and squeeze the thrust pad 5 and the expansion ring 6 by tightening the bolt 3, thereby restricting the axial displacement of the expansion ring 6.

[0061] The present invention has been disclosed above with preferred embodiments, but it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed structure and technical content to create equivalent embodiments without departing from the scope of the present invention. However, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method of using a tightening installation fixture, the tightening installation fixture comprising a locking assembly, a mandrel (2), a thrust pad (5), an expansion ring (6), and an adjusting pad (7), wherein one end of the mandrel (2) is provided with an annular limiting protrusion along the circumferential direction, and the annular limiting protrusion is integrally formed with the mandrel (2), the expansion ring (6) is sleeved on the outer circular surface of the mandrel (2), and an adjusting pad (7) is provided between one end of the expansion ring (6) and the limiting protrusion, the adjusting pad (7) is sleeved on the outer circular surface of the mandrel (2), the thrust pad (5) is provided on the other end of the expansion ring (6), and the thrust pad (5) is sleeved on the outer circular surface of the mandrel (2), a locking assembly is provided on the end of the thrust pad (5) away from the expansion ring (6), the locking assembly is sleeved on the mandrel (2), and the thrust pad (5) is tightly fitted to the other end of the expansion ring (6) through the locking assembly; The mandrel (2) is a stepped shaft. The mandrel (2) is coaxially provided with a tapered mating shaft section, a transition shaft section and a threaded shaft section from left to right. An annular limiting protrusion is sleeved on the outer circle surface of the large end of the tapered mating shaft section. The transition shaft section is set on the small end of the tapered mating shaft section, and one end of the transition shaft section is integrally formed with the small end of the tapered mating shaft section. The connection between the transition shaft section and the tapered mating shaft section forms a first positioning step. The threaded shaft section is set on the other end of the transition shaft section, and one end of the threaded shaft section is integrally formed with the other end of the transition shaft section. The connection between the threaded shaft section and the transition section forms a second positioning step. Its features are: The method of use is achieved through the following steps: Step 1: When installing the expansion and tightening installation fixture, first insert the mandrel (2) into the middle inner hole of the test transmission shaft (12), with the conical surface of the mandrel (2) fitting the large end of the shaft section close to the bottom of the middle inner hole; Step 2: Insert the adjusting shim (7) and the expansion ring (6) into the space formed between the test drive shaft (12) and the mandrel (2), and make the inner ring surface of the expansion ring (6) match the outer ring surface of the mandrel (2); Step 3: Install the propulsion assembly on the threaded section of the mandrel (2), and use the propulsion assembly to make the expansion ring (6) and the mandrel (2) move towards each other along the conical surface, so that the mandrel (2) radially tightens the expansion ring (6); The propulsion assembly includes a propulsion sleeve (8), a first O-ring (9), a propulsion cylinder rod (10), and a second O-ring (11). The propulsion cylinder rod (10) is a two-stage stepped shaft structure. The end face of the small-diameter end of the propulsion cylinder rod (10) is machined with a threaded hole that mates with the threaded shaft section on the mandrel (2). A positioning step is provided at the end of the threaded hole. The outer circular surface of the large-diameter shaft section of the propulsion cylinder rod (10) is machined with a first O-ring groove. The outer circular surface of the small-diameter shaft section of the propulsion cylinder rod (10) is machined with a second O-ring groove. The propulsion sleeve (8) is a two-stage stepped bushing that mates with the propulsion cylinder rod (10). The propulsion sleeve (8) is fitted on the propulsion cylinder rod (10). The first O-ring (9) and the second O-ring (11) are set between the propulsion sleeve (8) and the propulsion cylinder rod (10). The first O-ring (9) is set in the first O-ring groove, and the second O-ring (11) is set in the second O-ring groove. An oil inlet hole is machined on the end face of the large end of the propulsion cylinder rod (10). An internal thread is machined on the inner wall of the oil inlet hole to cooperate with the connection part of the external oil guide pipe. The end of the oil inlet hole is connected to the cavity formed between the step in the propulsion cylinder rod (10) and the step in the propulsion sleeve (8). Step 4: After the expansion ring (6) is radially tightened, remove the push assembly from the threaded shaft section of the mandrel (2), and tighten the locking assembly onto the threaded shaft section of the mandrel (2) to axially lock the expansion ring (6). Step 5: When it is necessary to disassemble the expansion installation fixture, first remove the locking assembly from the mandrel (2), and at the same time connect the external hydraulic oil pipe to the oil guide blind hole in the middle of the mandrel (2); Step 6: After the external hydraulic oil pipe is connected to the mandrel (2), oil is injected into the mandrel (2) through the external hydraulic oil pipe. The hydraulic oil flows into the gap between the mandrel (2) and the expansion ring (6), causing the expansion ring (6) and the mandrel (2) to move in opposite directions and causing the expansion ring (6) and the mandrel (2) to be separated. Step 7: With the expansion ring (6) and the mandrel (2) in a separated state, first remove the expansion ring (6) from the mandrel (2), and then remove the mandrel (2) from the middle inner hole of the test drive shaft (12).

2. The method of using the expansion and tightening installation fixture according to claim 1, characterized in that: The locking assembly includes a retaining ring (1), a thrust nut (4), and multiple bolts (3). The retaining ring (1) has multiple positioning holes machined equidistantly along the circumferential direction on its end face. The thrust nut (4) has multiple threaded holes machined equidistantly along the circumferential direction on its end face. Each threaded hole is coaxially corresponding to a positioning hole. The thrust nut (4) is sleeved on the end of the spindle (2) away from the adjusting pad (7). The thrust nut (4) is detachably connected to the spindle (2) by threads. The retaining ring (1) is set on the end of the thrust nut (4) away from the thrust pad (5). The retaining ring (1) is limited by a positioning groove located on the inner wall of the test drive shaft (12). The threaded section of each bolt (3) passes through a positioning hole in sequence and is set in a threaded hole. Each bolt (3) is threadedly connected to the thrust nut (4). The end of each bolt (3) contacts the thrust pad (5).

3. The method of using the expansion and tightening installation fixture according to claim 2, characterized in that: A positioning tapered hole is machined at the center of the large end face of the tapered mating shaft section in the mandrel (2) along the axial direction of the mandrel (2). An oil guide blind hole is machined at the center of the end face of the threaded shaft section away from the transition shaft section along the axial direction of the mandrel (2). Multiple branch flow holes are machined at equal intervals along the extension direction of the oil guide blind hole on the inner wall of the oil guide blind hole. Each branch flow hole group includes multiple branch flow holes. The multiple branch flow holes are distributed at equal intervals along the circumferential direction on the inner wall of the oil guide blind hole. One end of each branch flow hole is connected to the oil guide blind hole, and the other end of each branch flow hole is connected to the tapered outer circular surface of the tapered mating shaft section. An internal thread is machined on the inner wall of the open end of the oil guide blind hole to cooperate with the external oil guide pipe connection part.

4. The method of using the expansion and tightening installation fixture according to claim 3, characterized in that: The inner ring surface of the expansion ring (6) is a conical surface, the outer ring surface of the expansion ring (6) is a cylindrical surface, and the inner ring surface of the expansion ring (6) is fitted with the outer circular surface of the conical surface mating shaft section, and the outer ring surface of the expansion ring (6) is fitted with the inner hole surface of the test transmission shaft (12).

5. The method of using the expansion and tightening installation fixture according to claim 4, characterized in that: The specific operation of using the propulsion assembly to make the expansion ring (6) and the mandrel (2) move towards each other along the conical surface in step three is as follows: Step 31: Sleeve the push cylinder rod (10) onto the threaded section of the mandrel (2), and thread the push cylinder rod (10) and the mandrel (2) together until the end of the mandrel (2) contacts the positioning step on the push cylinder rod (10), confirming that the push cylinder rod (10) and the mandrel (2) are installed in place; Step 32: Set the external hydraulic oil pipe in the oil inlet hole on the propulsion cylinder rod (10) and fix the external hydraulic oil pipe to the propulsion cylinder rod (10) by thread; Step 33: Under the premise of ensuring that the external hydraulic oil pipe is fixedly connected to the propulsion cylinder rod (10), oil is injected into the gap formed between the propulsion cylinder rod (10) and the propulsion sleeve (8) through the external hydraulic oil pipe, so that the propulsion sleeve (8) and the propulsion cylinder rod (10) produce opposite displacements. The thrust of the propulsion sleeve (8) acts on the expansion ring (6) through the thrust pad (5), and the tension of the propulsion cylinder rod (10) acts directly on the spindle (2). Through the opposite displacement between the propulsion sleeve (8) and the propulsion cylinder rod (10), the spindle (2) and the expansion ring (6) produce opposite displacements along the conical surface, thereby making the spindle (2) and the expansion ring (6) in a tightened state.

6. The method of using the expansion and tightening installation fixture according to claim 5, characterized in that: The specific operation of fitting the locking assembly onto the transition section of the mandrel (2) in step four is as follows: Step 41: First, install the thrust nut (4) on the threaded section of the mandrel (2) through a threaded connection; Step 42: Set the retaining ring (1) for the hole on the end of the thrust nut (4) away from the thrust pad (5), and limit it by the positioning groove on the inner wall of the test drive shaft (12); Step 43: Pass the threaded section of each bolt (3) through a positioning hole on the retaining ring (1) and set it in a threaded hole on the thrust nut (4), and each bolt (3) is threadedly connected to the corresponding thrust nut (4); Step 44: Make the end of each bolt (3) contact the thrust pad (5), and squeeze the thrust pad (5) and the expansion ring (6) by tightening the bolt (3), thereby limiting the axial displacement of the expansion ring (6).

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