CN112008445A

CN112008445A - Blind hole slender shaft inner supporting method

Info

Publication number: CN112008445A
Application number: CN202010890899.4A
Authority: CN
Inventors: 鲁攀; 秦诗凡; 任琦峰
Original assignee: AECC South Industry Co Ltd
Current assignee: AECC South Industry Co Ltd
Priority date: 2020-08-29
Filing date: 2020-08-29
Publication date: 2020-12-01
Anticipated expiration: 2040-08-29
Also published as: CN112008445B

Abstract

A method for supporting a blind hole slender shaft in an elongated shaft comprises the following steps of A, preparing an extension rod and a sleeve part according to an inner cavity profile of a blind hole slender shaft part, wherein the extension rod comprises a rod head part and a rod body part which are connected in sequence, the sleeve part comprises two symmetrical semicircular components, B, gluing the semicircular components, clamping and bonding an inflating nozzle, and meanwhile, the rod body part is bonded, and the two semicircular components are bonded into the whole of the sleeve part at the same time. And step C, inserting the extension rod connected with the sleeve part in the step B into the inner cavity of the blind hole slender shaft part, inflating through the inflating nozzle to enable the flexible air pipe to be in close contact with the inner cavity of the shaft body to form an inner support, and enabling the rubber film to expand outwards to be in close contact with the inner cavity of the shaft body to form airtight sealing for the inner cavity of the shaft body. The method for supporting the slender shaft with the blind hole in the inner hole greatly improves the production efficiency.

Description

Blind hole slender shaft inner supporting method

Technical Field

The invention relates to the technical field of machining, in particular to a method for controlling deformation during grinding of an outer circular surface of a boss of a shaft body of a thin-wall hollow slender shaft part with a blind hole in an inner cavity.

Background

Fig. 1 is a schematic diagram of a schematic cross-sectional structure of a blind hole slender shaft part for an aircraft engine, and as shown in fig. 1, this blind hole slender shaft part 1 includes a shaft body 11 with a wall thickness of 0.5mm, five circular-ring-shaped bosses 12 are welded on the shaft body 11, a first end fitting 13 and a second end fitting 14 are welded at two ends of the shaft body 11 respectively, and are close to the first end fitting 13, the bosses 12 are provided with a sealing ring 15 bonded with the shaft body 11, the first end fitting 13 is provided with a blind hole 131 communicated with an inner hole of the shaft body 11, the second end fitting 14 is sequentially provided with a first communicating hole 141 with the same inner hole diameter of the shaft body 11 and a second communicating hole 142 with a larger diameter, and a thin-wall section 143 with a wall thickness of 0.85mm is arranged on a side wall of the second communicating hole 142.

The outer diameter phi 1 of the shaft body 11 is 15mm, the length L1 is greater than 900mm, the overall length L2 of the blind hole slender shaft part 1 is greater than 990mm, the depth L3 of the blind hole 131 is 10mm, the length L4 of the thin-wall section 143 is greater than 40mm, the outer circular surface of the boss 12 is an arc surface with the radius R equal to 12mm, and the thickness L5 of the boss 12 is 5 mm.

In the production process, the outer disc of boss 12 need carry out abrasive machining, and the processing back, the outer disc of boss 12 is beated and is required to be not more than 0.038, because shaft body 11 and the draw ratio of thin wall hollow slender shaft part 1 has all exceeded 60, moreover the wall thickness of shaft body 11 is only 0.5mm, consequently, in current course of working, can only process with minimum abrasive machining parameter, and the course of working still need measure at any time in order to ensure the requirement of beating to make production efficiency extremely low.

In addition, because the wall thickness of the shaft body 11 is only 0.5mm, the sealing ring 15 is easy to deform in the grinding process to fall off, when the sealing ring 15 integrally falls off, the risk is easy to control, and when the sealing ring 15 is only separated from a local connecting position, the sealing ring is difficult to detect, so that great hidden danger can be caused to an aeroengine using the part.

The applicant submits a patent application with the application number of 201910997022.2 and the name of 'a thin-wall hollow slender shaft part grinding deformation control method' in 2019, 10, 20, and in the technical scheme of the application, the thin-wall hollow slender shaft part grinding deformation control method is provided. In addition, the risk of separation of the connection positions of the sealing rings is effectively controlled.

However, because profiles of the outer circular surfaces of shaft parts with similar blind hole structures of different aero-engines have certain differences, in the production process, if the mandrel provided by 201910997022.2 is used for different similar shaft parts with the same inner diameter, the applicant finds that flutter is generated in the machining process, and therefore the product yield is seriously affected. In addition, the use of 201910997022.2 provides a mandrel that is relatively labor intensive to insert and remove due to the interference fit.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a method for supporting a blind hole slender shaft in order to reduce or avoid the problems mentioned above.

In order to solve the technical problem, the invention provides an inner support method for a blind hole slender shaft, which is used for forming an inner support from an inner cavity of a blind hole slender shaft part in the process of machining a molded surface of an outer circular surface of the blind hole slender shaft part, wherein the blind hole slender shaft part comprises a shaft body with the wall thickness of 0.5mm, a plurality of annular bosses are welded on the shaft body, a first end piece and a second end piece are respectively welded at two ends of the shaft body, a sealing ring which is bonded with the shaft body is arranged on the boss close to the first end piece, the first end piece is provided with a blind hole which is communicated with an inner hole of the shaft body, the second end piece is sequentially provided with a first communicating hole with the same diameter as the inner hole of the shaft body and a second communicating hole with a larger diameter, and the side wall of the second communicating hole is provided with a thin-wall section with the. Which comprises the following steps of,

step A, preparing an extension rod and a sleeve part according to the inner cavity profile of the blind hole slender shaft part, wherein the extension rod comprises a rod head part and a rod body part which are sequentially connected,

the top surface and the side wall of the rod head part are provided with first grooves which are crossed, the joint of the rod head part and the rod body part is provided with a first annular groove communicated with the first grooves, the first grooves and the first annular groove are sleeved with first rubber strips,

the pole body portion with the opposite terminal surface in pole head portion one side is provided with a air vent, the outer disc of pole body portion be provided with one with the pilot hole of air vent intercommunication, the outer disc winding of pole body portion is connected with flexible trachea, flexible trachea's one end plug-in connection to pilot hole, the other end is arranged in the pole head with the junction of pole body portion.

The sleeve part comprises two symmetrical semicircular components, the sleeve part is sequentially provided with a first cavity used for clamping the rod body part, a second cavity used for gas buffering and flow guiding, a third cavity used for clamping the inflating nozzle and a fourth cavity with internal threads along the axis direction, the outer circular surface of the sleeve part is provided with a conical surface inclined to the rod body part, the conical surface is provided with a gas guide hole communicated with the second cavity, and the conical surface is provided with a rubber membrane which can be elastically expanded outwards and covers the gas guide hole.

And step B, gluing the first cavity, the third cavity and the axial plane of the two semicircular components, clamping and bonding the charging connector in the third cavity, simultaneously bonding the first cavity and the rod body part by utilizing the first cavity, and simultaneously bonding the two semicircular components into the whole sleeve part.

And step C, inserting the extension rod connected with the sleeve part in the step B into the inner cavity of the blind hole slender shaft part, so that the head of the rod is inserted into the blind hole, then inflating through the inflating nozzle, so that the flexible air pipe can be in close contact with the inner cavity of the shaft body to form an inner support, and the rubber membrane expands outwards to form airtight sealing for the inner cavity of the shaft body in close contact with the inner cavity of the shaft body. And finishing the internal support of the blind hole slender shaft part.

Preferably, in step a, the length dimension of each part of the first rubber strip is 1-2mm smaller than the length dimension of the corresponding groove.

Preferably, in step a, the diameter of the rod head is 1.8mm smaller than that of the blind hole, the length of the rod head is 1.5mm longer than that of the blind hole, and the first rubber strip is a rubber strip which is made by injection molding and has a circular cross section. The cross-sectional radius was set to 1.5 mm.

Preferably, in step a, the shaft portion has a diameter of 1/2 to 2/3 of the shaft inner diameter.

Preferably, in step a, the outer diameter of the flexible air tube is set according to the following formula,

the outer diameter of the flexible air tube is > (the inner diameter of the shaft body-the diameter of the shaft body part) ÷ 2.

Preferably, in the step a, the flexible air pipe is wound on the outer circumferential surface of the shaft body part, and bonding is not required to be performed on the whole length, and only 5-10 bonding points are ensured.

Preferably, in step a, the shaft portion is provided with a continuous circumferential mounting groove connected with the vent hole.

Preferably, in step a, the maximum outer diameter of the sleeve member is 1 to 1.5mm smaller than the inner diameter of the second communication hole.

Preferably, in step a, the rubber film is formed by covering the tapered surface with a rubber material with a thickness of 2-3mm, and is fixed at two axial ends of the tapered surface by bonding.

Preferably, in step C, before the extension rod is inserted into the inner cavity of the blind hole slender shaft part, two O-ring seals with outer diameters slightly larger than the inner diameter of the second communication hole are adhesively assembled at two axial ends of the conical surface.

Preferably, in step C, the target aeration pressure is between 2.5 and 3.5 bar.

According to the blind hole slender shaft inner supporting method, the inflatable structure is used for effectively supporting the part, so that the integral rigidity of the part is enhanced, the deformation of the thin-wall part of the part during clamping and grinding of the grinding machine is effectively controlled, the grinding parameters can be improved, the working time required by grinding is greatly reduced, and the production efficiency is greatly improved. In addition, the risk of separation of the connection positions of the sealing rings is effectively controlled.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein the content of the first and second substances,

FIG. 1 is a schematic cross-sectional structural view of a blind hole slender shaft part for an aircraft engine;

FIG. 2 is a schematic diagram of a blind bore elongated shaft internal support method in accordance with an embodiment of the present invention;

FIG. 3 is a schematic partial cross-sectional structural view of the extension rod and sleeve member of FIG. 2 in an exploded condition;

FIG. 4 is a schematic perspective view of the head and part of the body of FIG. 3;

FIG. 5 is a schematic view of the half-section structure of FIG. 4;

FIG. 6 is a schematic structural diagram of the first rubber strip of FIG. 2;

fig. 7 is a schematic structural diagram of the semicircular assembly of fig. 3.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings. Wherein like parts are given like reference numerals.

FIG. 2 is a schematic diagram of a blind bore elongated shaft internal support method in accordance with an embodiment of the present invention; FIG. 3 is a schematic partial cross-sectional structural view of the extension rod and sleeve member of FIG. 2 in an exploded condition; FIG. 4 is a schematic perspective view of the head and part of the body of FIG. 3; FIG. 5 is a schematic view of the half-section structure of FIG. 4; FIG. 6 is a schematic structural diagram of the first rubber strip of FIG. 2; fig. 7 is a schematic structural diagram of the semicircular assembly of fig. 3. In fig. 7, a right view, a front view and a left view of the semicircular assembly of fig. 3 are shown by three views a, b and c, respectively. As shown in the figures 1-7 of the drawings,

against the background of the background, the applicant provided a core rod with interference fit and therefore laborious insertion and removal in the prior application with application number 201910997022.2 filed on 20/10/2019, and the group of inventors improved on the basis of the technical solution provided in the prior application with 201910997022.2, optimized both the internal support structure and the internal support method, specifically,

the invention provides a method for supporting a blind hole slender shaft in an inner cavity, which is used for forming an inner support from the inner cavity of a blind hole slender shaft part 1 in the process of machining the profile of the outer circular surface of the blind hole slender shaft part 1, the blind hole slender shaft part 1 comprises a shaft body 11 with the wall thickness of 0.5mm, a plurality of annular bosses 12 are welded on the shaft body 11, a first end head piece 13 and a second end head piece 14 are respectively welded and connected at two ends of the shaft body 11, a sealing ring 15 which is bonded with the shaft body 11 is arranged on the boss 12 which is close to the first end head piece 13, the first head piece 13 is provided with a blind bore 131 communicating with the inner bore of the shaft body 11, the second head member 14 is provided with a first communication hole 141 having the same diameter as the inner bore of the shaft body 11 and a second communication hole 142 having a larger diameter in this order, the side wall of the second communication hole 142 is provided with a thin-wall section 143 with the wall thickness of 0.85 mm. Which comprises the following steps of,

step A, preparing an extension rod 2 and a sleeve part 3 according to the inner cavity profile of the blind hole slender shaft part 1, wherein the extension rod 2 comprises a rod head part 21 and a rod body part 22 which are connected in sequence,

the diameter of the rod head part 21 is 1.8mm smaller than that of the blind hole 131, the length is 1.5mm longer than the length L3 of the blind hole 131, the top surface and the side wall of the rod head part 21 are provided with first grooves 211 which are crossed, the joint of the rod head part 21 and the rod body part 22 is provided with a first annular groove 212 communicated with the first groove 211,

first recess 211 with first annular 212 has cup jointed first rubber strip 5, first rubber strip 5 corresponds respectively first recess 211 with first annular 212 is provided with interconnect's cross 51 and first annular 52, the length dimension of each part of first rubber strip 5 is 1-2mm less than the length dimension of the groove that corresponds respectively, can ensure like this first rubber strip 5 with the zonulae occludens of pole head 21. The first rubber strip 5 is a rubber strip which is made in an injection molding mode and has a circular cross section. The cross-sectional radius may be set to 1.5 mm.

The end surface of the shaft portion 22 opposite to the shaft head portion 21 (i.e. the end surface of the side connected to the sleeve member 3) is provided with a vent hole 221, the outer circumferential surface of the shaft portion 22 is provided with an assembly hole 222 communicated with the vent hole 221, the outer circumferential surface of the shaft portion 22 is wound and connected with a flexible air tube 4, one end of the flexible air tube 4 is inserted into the assembly hole 222, and the other end is arranged at the connection position of the shaft head portion 21 and the shaft portion 22. One end of the flexible air tube 4 facing the rod head 21 may or may not extend out of the end face of the rod body 22, as long as normal ventilation is possible.

The shaft portion 22 is used to provide a rigid support of the whole structure in the shaft 11, and the diameter of the shaft portion 22 may be 1/2-2/3 of the inner diameter of the shaft 11, for example, for the blind shaft component 1 mentioned in the background, the outer diameter φ 1 of the shaft 11 is 15mm, the wall thickness is 0.5mm, that is, the inner diameter of the shaft 11 is 14mm, and in this case, the diameter of the shaft portion 22 may be 7-10 mm.

The outer diameter of the flexible gas tube 4 can be set according to the following formula,

the outer diameter of the flexible air tube 4 > (the inner diameter of the shaft body 11-the diameter of the shaft body part 22) ÷ 2,

the flexible air tube 4 may be obtained by modifying a commercially available infusion tube, for example, by cutting a 4X2.5 (outer diameter 4mm, inner diameter 2.5mm) infusion tube, or may be made of a butyl rubber material (tire tube material).

The diameter of the assembly hole 222 is larger than or equal to the outer diameter of the flexible air tube 4, and the flexible air tube 4 and the assembly hole 222 can be fixedly bonded by using an adhesive, that is, the flexible air tube 4 can be inserted into the assembly hole 222 for bonding after being coated with the adhesive.

When the flexible air tube 4 is wound on the outer circumferential surface of the rod body part 22, bonding on the whole length is not needed, only 5-10 bonding points are ensured, and the flexible air tube 4 is not dropped from the rod body part 22 after being inflated.

Referring to fig. 3 and 4, the shaft portion 22 may be pre-provided with a continuous surrounding installation groove 223 connected to the ventilation hole 221, which is more beneficial to increase the contact area during the bonding process of the flexible air tube 4 and the shaft portion 22, thereby increasing the bonding firmness and facilitating the shape maintenance of the flexible air tube 4.

The head portion 21 and the body portion 22 may be integrally formed, i.e. machined from a unitary metal bar stock, but of course, the head portion 21 and the body portion 22 may also be separately formed, e.g. machined from a metal bar stock, and then fixedly attached by providing a structure (not shown) such as a threaded connection.

Referring to fig. 3 and 7, the sleeve member 3 includes two symmetrical semicircular components 31, the sleeve member 3 is sequentially provided with a first cavity 311 for clamping the shaft portion 22, a second cavity 312 for buffering and guiding air, a third cavity 313 for clamping the charging connector 6, and a fourth cavity 314 with internal threads for facilitating assembly along an axial direction, an outer circumferential surface of the sleeve member 3 is provided with a tapered surface 32 inclined toward the shaft portion 22, the tapered surface 32 is provided with an air guide hole 321 communicated with the second cavity 312, and the tapered surface 32 is provided with an outwardly elastically expandable rubber film 322 covering the air guide hole 321. The diameter of the air-guide hole 321 may be 1-3 mm.

The semicircular member 31 may be formed of a resin material by injection molding, and the maximum outer diameter of the sleeve member 3 may be 1-1.5mm smaller than the inner diameter of the second communication hole 142, thereby facilitating the insertion of the second communication hole 142.

The rubber film 322 may be made by wrapping the tapered surface 32 with a rubber material having a thickness of 2-3mm, and fixing the rubber material at two axial ends of the tapered surface 32 by adhesion, so that the rubber film 322 can maintain the ability of generating elastic deformation at the axial middle position of the tapered surface 32.

Step B, gluing the first cavity 311, the third cavity 313 and the axial plane of the two semicircular components 31, clamping and bonding the charging connector 6 in the third cavity 313, simultaneously bonding the first cavity 311 and the rod body part 22 by utilizing the first cavity, and simultaneously bonding the two semicircular components 31 into the whole sleeve part 3.

The inflation nozzle 6 may be an air nozzle of a conventional ball type (e.g. basketball) having an axial length in the range of 8-30mm, and for the blind hole elongated shaft member 1 mentioned in the background, an air nozzle of 10mm in length may be preferably commercially available.

After the two semicircular assemblies 31 are simultaneously bonded to form the whole of the sleeve member 3, the rubber film 322 is disposed on the tapered surface 32. It is advantageous to fix the rubber material at both axial ends of the tapered surface 32 by bonding to obtain the rubber film 322.

And step C, inserting the extension rod 2 connected with the sleeve part 3 in the step B into the inner cavity of the blind hole slender shaft part 1, inserting the rod head part 21 into the blind hole 131, then inflating through the inflating nozzle 6, enabling the flexible air pipe 4 to be in close contact with the inner cavity of the shaft body 11 to form an inner support, and enabling the rubber film 322 to expand outwards to be in close contact with the inner cavity of the shaft body 11 to form airtight sealing for the inner cavity of the shaft body 11. Thus, the inner support of the blind hole slender shaft part 1 is completed.

In the process that the extension rod 2 is inserted into the inner cavity of the blind hole slender shaft part 1, the flexible air pipe 4 is not inflated, so that the flexible air pipe has certain flexible deformation capacity, the insertion operation can be conveniently carried out,

after the rod head 21 is inserted into the blind hole 131 in place, when an air pump is used to inflate through the inflation nozzle 6, the final inflation target pressure can be set to 2.5 to 3.5bar, and in the inflation process of the air pump, due to the previous insertion operation, the flexible air tube 4 is usually deformed to a certain extent, that is, the inner cavity space of part of the flexible air tube 4 is reduced, so that the inflation process makes the flexible air tube 4 swell and full, and at the same time, the rubber film 322 is expanded outwards to be in close contact with the inner cavity of the shaft body 11 to form an airtight seal for the inner cavity of the shaft body 11.

The inventors have found through practice that a pressure of 2.5 to 3.5bar (adjusted according to part size and the flexible gas tube 4 material and dimensions) is sufficient to form an effective support for the lumen of the blind bore elongate shaft part 1.

Of course, in order to ensure the air tightness during the inflation process, two O-ring seals (not shown in the drawings) having an outer diameter slightly larger than the inner diameter of the second communication hole 142 may be mounted in advance at two axial ends of the tapered surface 32 in a bonding manner, so that on one hand, the air tightness of the inner cavity of the blind hole slender shaft component 1 during the initial inflation process is ensured, thereby ensuring that the rubber membrane 322 obtains sufficient air pressure, and on the other hand, the connection firmness between the two axial ends of the rubber membrane 322 and the tapered surface 32 is further ensured by the two O-ring seals, thereby avoiding the rubber membrane 322 from being degummed due to the excessive air pressure.

Aerify the completion the blind hole slender axles part 1 can be used to the lathe and carry out turning or abrasive machining, in the course of working, because there is the swelling in the blind hole slender axles part 1 flexible trachea 4 directly supports, just the space outside flexible trachea 4 has pressure gas to support, consequently promotion that can be fine rigid support in the 1 outer disc course of working of slender axles part.

After the processing is finished, only the inflation nozzle 6 needs to be used for deflation, so that the inner cavity of the blind hole slender shaft part 1 recovers atmospheric pressure, the flexible air pipe 4 can be softened, and the extension rod 2 can be easily taken out.

As mentioned above, the fourth cavity 314 is provided with internal threads, so that during pushing in and pulling out, a screw (not shown) provided with external threads matching with the internal threads of the fourth cavity 314 can be used to provide a force application point extending to the outside of the blind hole slender shaft component 1, thereby facilitating the operation.

It should be appreciated by those of skill in the art that while the present invention has been described in terms of several embodiments, not every embodiment includes only a single embodiment. The description is given for clearness of understanding only, and it is to be understood that all matters in the embodiments are to be interpreted as including technical equivalents which are related to the embodiments and which are combined with each other to illustrate the scope of the present invention.

The above description is only an exemplary embodiment of the present invention, and is not intended to limit the scope of the present invention. Any equivalent alterations, modifications and combinations can be made by those skilled in the art without departing from the spirit and principles of the invention.

Claims

1. The utility model provides a method of supporting in blind hole slender axles, its is arranged in the profile course of working of the excircle face of blind hole slender axles part, follows the inner chamber of blind hole slender axles part forms and supports, blind hole slender axles part includes the axle body of wall thickness 0.5mm, the welding has the annular boss of a plurality of rings on the axle body, the both ends of axle body welded connection respectively have first end spare and second end spare, are close to first end spare the boss be provided with one with the sealing washer that the axle body bonds, first end spare be provided with the blind hole of the hole intercommunication of axle body, second end spare be provided with in proper order with the same first intercommunicating pore of the hole diameter of axle body and major diameter's second intercommunicating pore, second intercommunicating pore lateral wall is provided with the thin wall section of wall thickness 0.85 mm. Characterized in that it comprises the following steps,

2. The method according to claim 1, wherein in step a, the diameter of the rod head is 1.8mm smaller than the diameter of the blind hole and the length is 1.5mm longer than the length of the blind hole, and the first rubber strip is a rubber strip with a circular cross section and is manufactured by injection molding. The cross-sectional radius was set to 1.5 mm.

3. The method of claim 1 wherein in step a, the shaft portion diameter is 1/2 to 2/3 of the shaft inner diameter.

4. The method of claim 1, wherein in step A, the outer diameter of the flexible gas tube is set according to the following formula,

5. The method according to claim 1, wherein in step a, the flexible air tube is wound around the outer circumferential surface of the shaft portion without bonding over the entire length, and only 5-10 bonding points are secured.

6. A method according to claim 5 wherein in step A the shaft portion is provided with a continuous circumferential mounting groove connected to the vent.

7. The method of claim 1, wherein in step a, the maximum outer diameter of the sleeve member is 1-1.5mm smaller than the inner diameter of the second communication hole.

8. The method according to claim 1, wherein in step a, the rubber film is formed by covering the conical surface with a rubber material having a thickness of 2-3mm and is fixed by bonding at both axial ends of the conical surface.

9. The method as claimed in claim 8, wherein in step C, two O-rings having an outer diameter slightly larger than the inner diameter of the second communication hole are adhesively fitted at both axial ends of the tapered surface before the extension rod is inserted into the inner cavity of the blind hole elongated shaft part.

10. The method of claim 1, wherein in step C, the target inflation pressure is 2.5 to 3.5 bar.