KR20100087075A

KR20100087075A - Method and system for processing a sheet of material

Info

Publication number: KR20100087075A
Application number: KR1020107005372A
Authority: KR
Inventors: 호에 추안 콴; 카르 리 탄; 타케후미 호소이
Original assignee: 파나소닉 주식회사
Priority date: 2008-06-24
Filing date: 2009-05-27
Publication date: 2010-08-03
Also published as: EP2291265A1; SG157979A1; CN101801607A; WO2009157874A1; JP2011525430A

Abstract

A sheet material processing method and processing system are provided. The sheet material processing method includes providing a particle flux impinging on the sheet material and moving the sheet material relative to the particle flux such that the particle flux can impinge on selected areas of the sheet material.

Description

Sheet material processing method and processing system {METHOD AND SYSTEM FOR PROCESSING A SHEET OF MATERIAL}

The present invention relates to sheet material processing methods and processing systems, and sheet material and compressors comprising one or more reed valves.

Compressors are an integral part of cooling systems such as air conditioners and refrigeration units. The compressor generally introduces and compresses a piston, reed suction and refrigerant gas operable to generate a differential pressure within the cylinder and at atmospheric pressure into the cylinder and discharges the refrigerant gas into the discharge plenum of the cylinder head. Outlet valves. In this manner the reed valves serve as check valves for the unidirectional flow of the refrigerant gas.

Since the reed valves are exposed to repeated fatigue and stress, the material used for the reed valves should have enhanced fatigue strength and high durability. Reed valves are typically manufactured by stamping operation of a press machine and are inverted and cylindrical by a tumbling medium that smoothes cut-edges and develops compressive residual stresses on the reed valves surface.

Almost all defects due to fatigue and stress corrosion occur at the surface of the reed valves. Moreover, it has been found that cracks do not start or develop in the compressive stress region. Thus, the compressive residual stress produced at the surface of the reed valves increases fatigue limit and resists fatigue corrosion, stress corrosion cracking, hydrogen assisted cracking, fretting, galling and cavitation erosion. It has a significant effect on enhancing this.

However, the lead tumbling process involves the tumbling medium which is prone to knocking of the reed valves and causing dents and scratches on the surface of the reed valves as shown in FIG. 10. This causes a new defect that fatigue cracks occur on the surface of the reed valves and can reduce the fatigue strength of the reed valves.

Since the tumbling medium such as stone used in the lead tumbling process has a relatively large size, it may be difficult to be introduced into the narrow interior of the reed valves, particularly the slit area. Therefore, there is a problem that the edges of the reed valves cannot have a proper radius.

The lead tumbling process is more than a random process and is a time dependent and time consuming process. That is, a long tumbling time is required to obtain a consistent compressive stress and to obtain an edge radius. On the other hand, the compressive stress generated by the lead tumbling process is not relatively high. For example, it has a stress in the range of approximately -400 MPa for heat treated high carbon rolled steel and a stress in the range of approximately -600 MPa for stainless steel. Thus, the life of the reed valves may not be prolonged significantly in response to repetitive fatigue and stress occurring during operation of the compressor unit.

For the same reason, there is a need for providing a sheet material processing method and a processing system.

An object of the present invention is to provide a sheet material processing method and processing system that can solve the above problems.

According to the first object of the present invention, a sheet material processing method is provided. The sheet material processing method includes providing a flux of particles impinging on the sheet material, and moving the sheet material such that the particle flux can impinge on selected areas of the sheet material.

The sheet material processing method may further include using a mask having exposed areas corresponding to critical areas of the sheet material.

The mask can move with the sheet material relative to the particle flux such that the particle flux is impingeable on select regions of the sheet material.

The selection regions of the sheet material may include one or more slit regions.

The selection areas of the sheet material may comprise one or more maximum load section areas.

The first mask defines one or more masking slits for shot peening of the one or more slit regions. The second mask defines one or more maximum load masking regions for shot peening of the one or more maximum load section regions. The sheet material processing method may include sequentially using the first mask and the second mask.

The sheet material processing method may further comprise deburring the cutting edges of the slits resulting from the collision of the particle flux.

The sheet material processing method may further comprise applying a compressive residual stress to the maximum load bearing regions.

Examples of the particles may include one selected from the group consisting of glass beads, steel shot, stainless steel shot, stainless steel grid, iron power and aluminum oxide.

The particles may have a diameter in the range of about 0.05 mm to about 2.8 mm.

The seat member may comprise reed valves.

According to the second object of the present invention, a sheet material processing system is provided. The system includes a source of particle flux impinging on the sheet material and means for moving the sheet material relative to the particle flux such that the particle flux impinges on a selected area of the sheet material.

The sheet member moving means may include an X-Y table.

The particle source may comprise particles dispersed in a compressed discharge fluid.

The system may include a mask having exposed areas corresponding to critical areas of the sheet material.

According to a third object of the invention there is provided a seat material comprising reed valves treated as defined in the first object.

According to a fourth object of the present invention there is provided a compressor unit having a seat member comprising reed valves defined in the third object.

The sheet material processing method and sheet material processing system through the shot peening process of the present invention as described above can solve the problems of dents and scratches associated with the tumbling process and can obtain a consistent compressive stress and edge radius. .

Features and other advantages of the present invention will be more clearly understood by describing various embodiments in detail with reference to the detailed description and the accompanying drawings.
1 is a schematic view showing a side view of a shot peening apparatus according to an embodiment of the present invention.
2A and 2B are schematic diagrams showing a plan view of a shot peening apparatus each including jig A and jig B according to an embodiment of the present invention.
3 is a schematic view showing a cross-sectional view of the compressive region and the tension region below the sheet material surface after performing the shot peening process according to an embodiment.
4A and 4B are schematic diagrams respectively showing a plan view and a bottom view of a reed valve after performing a shot peening process according to an embodiment of the present invention.
FIG. 5 illustrates a set of check point measurements for the radius of curvature generated at the edges of a reed valve after performing a shot peening process in accordance with one embodiment of the present invention.
FIG. 6 is a flow diagram representing different processes performed on reed valves in a first machine generating radius at the edges and a second machine generating compressive stress in accordance with one embodiment of the present invention.
7 is a schematic view showing a side view of a jig transporting apparatus and an assembling apparatus according to an embodiment of the present invention.
8 is optical microscope images of reed valves showing portions without dents after performing a shot peening process using different shot media in accordance with one embodiment of the present invention.
9 is a digital image of a reed valve after performing a shot peening process according to an embodiment of the present invention.
10 are optical microscope images showing dent marks and scratch marks that can be produced by a read tumbling process.
FIG. 11 is a table showing reliability measurement results for lead valves of stainless steel and flapper steel after performing the shot peening and lead tumbling process.
12 is a flowchart showing a sheet material processing method according to an embodiment of the present invention.
13 is a schematic view showing the exposed exterior of a reciprocating compressor.

1 is a side view of a shot peening processing apparatus 112 applied according to an embodiment of the present invention. Small spherical media 102 referred to as shots are ejected toward the multilayer composite consisting of a mask and reed valves 106 of a particular shape at a distance corresponding to reference 110 from the nozzle 100. The mask has the form of a jig including an upper jig plate fixture 104 and a lower jig plate fixture 108. Reed valves 106 are fixed between upper jig plate fixture 104 and lower jig plate fixture 108. Examples of shots 102 include glass beads, stainless steel shots, and aluminum oxide with diameters ranging from 0.053 to 2.8 mm.

The upper jig fixture 104, the reed valves 106 and the lower jig fixture 108 are stacked together and positioned on the X-Y table 114. The stacked upper jig fixture 104, reed valves 106, and lower jig fixture 108 may be automated to move in a designated pattern as shown by the double arrow in FIG. 1. Thus, shots 102 that are released at high pressure may fall over, around, and towards reed valves 106. As a result, a predictable pattern of relative movement of the shots 102 and the reed valves 106 can be obtained, thereby creating a consistent high compressive residual stress within the radius of the edges and the maximum load region of the reed valves 106. .

2A and 2B are plan views of the shot peening apparatus 112 respectively showing the upper jig A fixture 200 and the upper jig B fixture 204 according to embodiments of the present invention. The upper jig A fixture 200 and the upper jig B fixture 204 are smaller than the reed valves 106 and expose the edge portions of the reed valves 106. The upper shaped jig A fixture 200 has a narrow shot peening process slit 202 to create a radius of the edges while preventing shots 102 from colliding with noncritical regions of the reed valves 106. To be run on the The specific shape of the upper jig B fixture 204 prevents the shot 102 from colliding with the non-critical regions of the reed valves 106 while the shot peening process causes the maximum load region 206 of the reed valves 106 to rest. In order to enhance the compressive residual stress in the region. These two pinning processes may be performed at different stages. The lower jig fixture 108 includes a shape similar to the upper jig A fixture 200 or the upper jig B fixture 204 to allow the shot peening process to be performed on the opposite surface of the reed valves 106.

In the shot peening process, the surface of the reed valves 106 is attacked by shots 102 dispersed in the compressed fluid discharged from the nozzle 100. Each particle of the shots 102 attacking the reed valves 106 acts as a fine pinning hammer leaving a small groove or dimple on the surface of the reed valves 106. The surface of the reed valves 106 must be tensioned to create the dimples. In embodiments, in the regions where the shot peening process is performed, a change in color or appearance may be sensed as illustrated in FIG. 9. For example, the area where shot peening of the flapper steel has occurred can be polished.

FIG. 3 shows the compression zone 300 and the tension zone 302 formed below the seating surface or in this embodiment after the grooves 304 are created due to the impact of the shots 102 in the reed valves 106. have. Below the surface, the sheet material creates a hemisphere 300 of cold-working material subjected to high compressive stress under the groove 304 to maintain a circular shape. In Fig. 3, circles 306 represent component particle units of the sheet material.

4 is a plan view and a bottom view of the reed valves 106 after the shot peening process. Reed valves 106 include narrow slits 202 that allow tongue shaped lead portion 400 to move in operation within the compressor. Circles 1 to 5 are checkpoints indicating the positions at which the curvature and consistency of the radius created at the edges are measured as a result of the deburring effect of the shot peening process. The result of the measurement for the reed valves 106 is shown in FIG. 5 at a rate of 500 times for both axes. Circles 500 in FIG. 5 coincide with the measured curvature 502 to measure the curvature 502 of the radius created at the edges and determine the consistency of the magnitude of the radius. In FIG. 5, relatively large circles 500 exhibit a relatively gentle curvature at the edges, which shows that a radius can be generated at the edges by the shot peening process. In contrast, relatively small circles 500 indicate relatively sharp edges. The sharp edges are prone to dents, which can cause the formation of stress points on the surface of the reed valves. In contrast, the gentle curvature of the edges obtained by the shot peening process can reduce the formation of the stress points. In addition, the relative similarity of the size of the circles 500 coinciding with the curvature 502 indicates the consistency of the radius size of the edges obtained by the shot peening process.

Embodiments of the present invention may provide a method for deburring the cutting edge and may also enhance the compressive residual stress within the maximum load region of the reed valves of the compressor. The process allows abrasives to be guided and penetrate into selected regions of the reed valves without deformation, thereby providing a more reliable compressor including reed valves with high fatigue durability. According to embodiments, deformed portions are easily formed by using jigs for shot peening on selected areas on one or both of the surfaces of the reed valves. Performing the shot peening process on the entire surface of one surface of the reed valves without using the jigs may cause deformation and warping of the reed valves. The warping effect can be mitigated by performing a shot peening process on the entire surface of both sides of the reed valves, but still fine warpage and deformations may be present on the reed valves.

According to the shot peening process according to the embodiments, the mechanical properties can be improved and erosion by fatigue fracture, fatigue corrosion, stress corrosion cracking, hydrogen assisted cracking, fretting, galling and cavitation can be achieved. Increasing the resistance can significantly extend component life.

The compressive stress for tumbling commercial reed valves has a stress of about -400 MPa for heat treated high carbon rolled steel and a stress in the range of about -600 MPa for stainless steel. Depending on the shape of the shot medium used in the embodiments of the present invention, high compressive stress can be obtained without deformation of the parts. For example, using glass beads under a pressure of 2 bar at a period of 20 seconds, a stress of about -730 MPa or more can be obtained for heat treated high carbon rolled steel. In general, high carbon rolled steel strips heat treated in a vacuum furnace in which impurities are controlled have been used as a dedicated material for compressor reed valves. Sometimes stainless steel with improved fatigue strength is also used but is not widely used due to its high cost. Shot pinned reed valves according to embodiments can enhance fatigue strength and provide an opportunity to use low cost, high carbon rolled steel instead of expensive stainless steel.

Table 1 shows the flapper steel having a thickness of 0.512 mm after performing a shot peening process using shot media having different sizes at a period of 20 seconds under the pressure of 2.0 to 2.5 bar using the jig A and jig B of the embodiments. The measurements of compressive stresses occurring are shown. The compressive stress was measured using X-ray diffraction analysis for residual stress measurement. As can be seen from Table 1, a relatively high compressive stress of -730 Mpa or more can be obtained from the shot peening process.

FIG. 11 shows Table 1100 showing the results of measuring the compressive stress for the reed valves of stainless steel and flapper steel after shot peening and tumbling processes. The compressive stresses of the reed valves were respectively measured before and after flapping or reed displacement operations occurred on the reed valve. As shown in FIG. 11, measurements were taken showing consistent compressive stresses while minimizing overall denaturation for the reed valves. In addition, the shot valve-processed reed valves showed relatively higher reliability and compression stress than the reed valves subjected to the tumbling process.

FIG. 6 is a flow diagram illustrating different processes respectively performed on reed valves 106 in a first machine that generates radii at edges and a second machine that generates compressive stresses in accordance with embodiments of the present invention. to be. The initial process includes a step 602 of checking the thickness to prevent accidental loading of two or more reed valves and a step 604 of loading the reed valve 106 onto the jigs. Jig A and the four reed valves are integrally or individually stacked together to form assembly 600. An assembly 600 of jig A and reed valves 604 is disposed in the first machine 606 and is provided with a first station for performing shot peening 608 that creates a radius at the edges in the first machine. 608, a second station where blowing 610 for removing debris is performed and a third station where sequential separation 612 of the upper and lower jig A fixtures from the reed valves 604 is performed at a period of 20 seconds. do. In one embodiment, the shot peening process may be performed on the upper and lower surfaces of the reed valves 604 by flipping the jigs after using one nozzle. According to another embodiment, the shot peening process may be performed simultaneously or sequentially on both surfaces of the reed valves 604 using one nozzle above the jig and another nozzle below the jig and thus the process It can save time.

After the process, the reed valves 604 are removed from the first machine 606 and transferred to the second machine for the next process. Jig B and reed valves 604 are stacked together to form an assembly 614 and placed into a second machine 616. The second machine is a first station that performs shot peening 618 for 5 seconds to create compressive stress, a second station that provides blow 620 to remove debris, a third station where cleaning 622 is performed, A fourth station is provided with blower 624 and a fifth station that sequentially separates 626 the upper and lower jig B fixtures from the reed valves 604. Reed valves 604 are then removed from second machine 626.

7 illustrates an assembly process 700. For example, before the reed valves 704 enter the first machine and / or the second machine, the upper jig fixture 702 is lowered and the lower jig fixture 706 is raised to protect the reed valves 704. And stacked with reed valves 704 to form assembly 708. When removed later in the process, i.e., from the first machine and / or the second machine, the assembly 708 is moved with the jigs through a separation process 710 where the upper jig fixture 702 rises and the lower jig fixture descends. Are separated into reed valves 704. Reed valves 704 are conveyed for the next assembly process 700 while the upper jig fixture 702 and the lower jig fixture 706 return to the initial position.

12 is a flowchart 1200 illustrating a method of processing a sheet material according to an embodiment. In a first step 1202, particle flux is provided to impinge on the sheet material. In a second step 1204 the sheet material is moved relative to the particle flux such that the particle flux can impinge on selected areas of the sheet material.

Those skilled in the art will appreciate that various modifications and changes can be made to the arrangement of the machines for the shot peening process without departing from the spirit and scope of the invention.

According to embodiments of the present invention, the shot peening process may generate portions without dents. Since the pinning process is performed for each part individually, problems associated with the lead tumbling process can be solved. In the tumbling process, knocking is inherent, and dents or scratches may occur in the portions. FIG. 8 is optical microscopic images at 200 times magnification of reed valves shot shot using different shot media in accordance with this embodiment, showing portions without dents.

The lead tumbling process is more than a random process and is very time dependent. The tumbling process requires a long tumbling time to achieve consistent compressive stress and radius of edges. According to the embodiments of the present invention, each part is shot peened separately while the variables are controlled, thereby improving the above problem.

The shot peening process according to an embodiment of the present invention may be performed using a shot medium having a relatively small size, for example, glass beads having a diameter of about 253 mm. The present embodiment can provide a particularly efficient process for parts that are thin, such as lead suction or discharge valves, and parts that are merged with narrow slits having a width of about 0.5 mm or less.

Referring to FIG. 13, there is shown an application of a seat material processed in accordance with one embodiment of the present invention, ie reed valves in compressor 1300. The interior of the compressor 1300 for hermetic gas-compression cooling is shown in FIG. 13. The compressor 1300 has a suction inlet pipeline 1302, a suction muffler 1304 and a cylinder head 1308. The suction muffler 1304 is disposed inside the shell 1306 of the compressor 1300. The suction muffler 1304 is connected to a cylinder head 1308 having a suction plenum 1316 and an outlet plenum 1314 therein. The suction plenum 1316 receives a lower temperature gas, while the exhaust plenum 1314 receives a higher temperature compressed gas from a cylinder chamber (not shown). The suction plenum 1316 and the discharge plenum 1314 are connected to the cylinder chamber through the suction reed valve 1315 and the discharge reed valve 1317, respectively. Exhaust plenum 1314 is further connected to exhaust pipeline 1318 through muffler cover 1310 and exhaust line 1312 to exhaust the high temperature compressed gas in the cooling system.

Although the above has been described with reference to embodiments of the present invention, those skilled in the art may variously modify the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. It will be appreciated that it can be changed.

100: nozzle 102: spherical medium
104: upper jig plate fixture 106: reed valve
108: lower jig plate fixture 112: shot peening device
114: XY table 200: upper jig A fixture
202: slit 204: upper jig B fixture
206: maximum load area 300: compression area
302: tensile region 304: groove
304: particle unit 600: assembly
604: reed valve 606: the first machine
610: Blowing air 616: Second machine
702: upper jig fixture 706: lower jig fixture
1300: Compressor 1302: Suction Inlet Pipeline
1304: suction muffler 1306: shell
1308: cylinder head 1310: muffler cover
1312: discharge line 1314: discharge plenum
1315 Suction Reed Valve 1316 Suction Plenum
1317: discharge reed valve 1318: discharge pipeline

Claims

Providing particle flux impinging on the sheet material; And
Moving the sheet material relative to the particle flux such that the particle flux impinges on a selected region of the sheet material.

The method of claim 1,
And using a mask having exposed areas corresponding to critical areas of said sheet material.

The method of claim 2,
And the mask moves with the sheet material relative to the particle flux such that the particle flux impinges on a selected region of the sheet material.

The method according to any one of claims 1 to 3,
And wherein said selected regions of said sheet material have one or more slit regions.

The method according to any one of claims 1 to 4,
And wherein said selected regions of said sheet material comprise one or more maximum load section regions.

The method according to any one of claims 4 to 5,
The first mask defines one or more masking slits for performing shot peening in the one or more slit regions, and the second mask performs shot peening in the one or more maximum load section regions. Defining a maximum load masking regions for and using the first and second masks sequentially.

The method according to claim 6,
And deburring the cutting edges of the slits resulting from the impingement of the particle flux.

The method according to claim 6 or 7,
Applying a compressive residual stress to the maximum load bearing regions.

The method according to any one of claims 1 to 8,
And the particles comprise any one selected from the group consisting of glass beads, steel shots, stainless steel shots, stainless steel grids, iron power and aluminum oxide.

The method of claim 9,
And wherein said particles have a diameter in the range from about 0.05 mm to about 2.8 mm.

The method according to any one of claims 1 to 10,
And said seat member comprises reed valves.

A particle flux source impinging on the sheet material; And
And means for moving said sheet material relative to said particle flux such that said particle flux can impinge on selected regions of said sheet material.

The method of claim 12,
And a mask having exposed areas corresponding to critical areas of the sheet material.

The method according to claim 12 or 13,
And said means for moving said sheet material comprises an XY table.

The method according to any one of claims 12 to 14,
And wherein said particle flux source comprises particles dispersed in a compressed discharge fluid.

A seat member comprising reed valves, treated according to the seat member treatment method of claim 1.

Compressor unit with seating material comprising the reed valves according to claim 16.