JP6518098B2 - Cylinder block casting method - Google Patents

Description

  The present invention relates to a method of casting a cylinder block, and more particularly to a method of casting a cylinder block in which a journal piece is cast in a journal portion.

  Conventionally, for example, in a vehicle engine, a light alloy cylinder block such as an aluminum-based alloy is widely used to reduce weight.

  A cylinder block made of such an aluminum-based alloy has a journal portion for supporting a crankshaft, and a journal piece of an iron-based material is cast in the journal portion for the purpose of improving the strength.

  When casting such a cylinder block, since the journal piece is covered with the base material of the aluminum-based alloy, the journal piece can not be fixed directly to the casting mold, as described in Patent Document 1; There is widely known a method of fixing and casting to a child using a pin, a wire or the like.

  Furthermore, for example, as disclosed in Patent Document 1, there is a method of casting a cylinder block made of an aluminum-based alloy by inserting and fixing one end of a journal piece into a hole formed in a casting mold.

  Further, as disclosed in Patent Document 2, in a casting apparatus for casting a journal piece having an oil hole and a bolt hole formed in a journal portion of a cylinder block, a casting pin provided for a fixed mold and positioning There is a method of inserting the pin into the oil hole and the bolt hole of the journal piece to fix and cast the journal piece in the casting mold.

  Further, in Patent Document 3, a holding pin is provided in a fixed mold, a guide pin is fixed in a movable mold, and the journal piece is held in the cavity by fitting the holding pin and the guide pin into bolt holes of the journal piece. A method of casting a lower case to be cast is disclosed.

JP-A-11-210751 Japanese Utility Model Application Publication No. 2-93059 JP-A-11-336740

  However, when the journal piece is fixed to the core using a pin or a wire as in Patent Document 1 described above, there is a concern that the journal piece may be displaced during casting. If misalignment occurs in the journal piece, the desired strength of the journal piece can not be obtained, the bearing surface of the journal portion becomes a distorted cylindrical shape, and the coefficient of friction with the rotating crankshaft increases. As a result of the increase in the coefficient of friction, the wear of the crankshaft, the journal, and the like becomes severe, and the fuel efficiency, performance, durability, and the like of the engine deteriorate, which causes vibration and noise.

  Further, according to the method of fixing one end of the journal piece to a casting mold and casting as in Patent Document 1, the journal piece is fixed at the time of casting, and positional deviation of the journal piece is suppressed. However, the size of the journal piece is increased, and the interface between the journal piece and the base material is exposed to the outer surface of the cylinder block in the cast cylinder block, so for example, through the bolt hole formed in the journal It is feared that the oil which has entered the minute gap between the journal piece and the base material from the bearing side exudes to the outside and contaminates the outer surface and the periphery of the cylinder block, and the consumption of oil increases. In addition, air and moisture infiltrate into the interface between the journal piece and the base material from the outside, the joint strength of the part decreases, the strength due to the journal piece decreases, and the crankshaft rotates with the deformation of the journal part. This leads to an increase in the coefficient of friction, which intensifies the wear of the crank shaft and the journals, which lowers the fuel efficiency, performance, durability and the like of the engine, and causes vibration and noise.

  As in Patent Document 2, according to the method of fixing and casting the journal piece by inserting the oil hole or bolt hole formed in the journal piece into the die-casting pin and the positioning pin of the mold, casting is performed in the cavity when casting Positional displacement of the journal piece, such as floating of the journal piece by molten metal introduced, is concerned.

  As in Patent Document 3, when the journal pin is fixed to the fixed type by the pressing pin and the movable guide pin, in the lower case after casting, the through hole connecting the interface between the journal piece and the base material to the outside by the pressing pin etc. Similarly to Patent Document 1, the oil that has entered the minute gap between the outer peripheral surface of the journal piece and the base material from the bearing side through the bolt holes exudes to the outside, and the consumption of oil increases. On the other hand, there is a concern that air or moisture infiltrates from the outside into the interface between the outer peripheral surface of the journal piece and the base material, and the bonding strength of the portion decreases, and the desired strength by the journal piece can not be obtained.

  Therefore, an object of the present invention made in view of such a point is to provide a casting method of a cylinder block which is improved in strength by a journal piece and which has no leakage of oil to the outside and which is excellent in durability.

  The method of casting a cylinder block according to claim 1 achieves the above object by positioning and supporting a journal piece in a cavity surface and a cavity in which a journal portion forming portion for forming the shape of a journal portion of a cylinder block is formed. A journal piece of ferrous material is cast in the journal using a casting mold having a lower mold provided with a journal piece support and an upper mold provided with a cavity surface for shaping the outer surface shape of a cylinder block. In a method of casting a light alloy cylinder block, the light alloy holding member mounted on the cavity face of the upper mold is brought into contact with the journal piece positioned by the journal piece support to hold the journal piece And, in the held state, the cavity is cast by hot-water filling the light metal melt into the cavity. Characterized in that it.

  According to this, the journal piece is fixed and cast in a predetermined position by the journal piece support portion formed in the lower mold and the light alloy press member mounted on the cavity face of the upper mold, and the press member is The melt of the light alloy melts and integrates with the base material to cast the journal piece, and the interface between the journal piece and the base material is reliably cut off from the outer surface of the cylinder block.

  As a result, the journal piece is cast into the desired position, the desired strength is obtained by the journal piece, the journal portion is held with high accuracy, and the coefficient of friction with the rotating crankshaft is reduced to obtain the oil. The consumption is suppressed and the wear of the crank shaft, the journal and the like is reduced, the fuel consumption, performance, durability and the like of the engine are improved, and the generation of vibration and noise is further suppressed.

  The interface between the outer peripheral surface of the journal piece and the base material does not communicate with the outer surface of the cylinder block, and the oil from the bearing side to the interface between the journal piece and the base material through the bolt hole formed in the journal Oil does not exude to the outer surface from the interface between the journal piece and the base material even if it infiltrates, and contamination of the outer surface of the cylinder block with oil is avoided, and oil consumption is suppressed. .

The invention according to claim 2 is the method for casting a cylinder block according to claim 1, wherein the upper mold cavity surface is in contact with a journal piece that protrudes from the cavity surface and is positioned on the journal piece support. A pressing member mounting step of mounting the possible pressing member, a journal piece setting step of setting the journal piece in the journal piece support portion, and bringing the pressing member into contact with the journal piece set in the journal piece support portion A clamping step of clamping, a hot water supply step of hot-water filling the light alloy melt in the clamped cavity, and a solidifying step of solidifying the hot-melt filled light alloy melt while holding the clamping state; It is characterized by comprising a mold opening process for separating the lower mold and the upper mold.

  According to this, by attaching the pressing member to the cavity face of the upper mold and clamping the journal piece in the state where the journal piece is set in the journal piece support portion, the pressing member contacts the journal piece set in the journal piece support portion. The casting method of the cylinder block according to claim 1 can be carried out by hot-water filling the light alloy molten metal in the cavity in which the journal piece is held in the desired position and the mold-clamped cavity is in contact.

  The invention according to claim 3 is the method for casting a cylinder block according to claim 1 or 2, wherein the pressing member is in the form of a shaft including a base and a position holding portion integrally formed with the base, The cavity surface of the upper mold has a recessed pressing member mounting hole, and the pressing member is mounted in a state where the base is inserted into the pressing member mounting hole and the position holding portion protrudes from the cavity surface. It features.

  According to this, by inserting the base of the pressing member into the pressing member mounting hole in which the cavity surface of the upper mold is recessed, the pressing member can be easily attached to the upper mold.

  The invention according to claim 4 is characterized in that, in the casting method for a cylinder block according to claim 3, the position holding portion is subjected to surface area expansion processing on the outer periphery.

  According to this, by performing the surface area expansion process of the bolt-like unevenness, for example, on the position holding portion of the pressing member, the area to be in contact with the light alloy melt is secured at the casting, and the light alloy melt easily and efficiently It is dissolved.

  According to the present invention, the journal piece is fixed and cast in a predetermined position by the journal piece support formed in the lower mold and the light alloy press member mounted on the cavity face of the upper mold, and the press member Is melted by the light alloy melt and integrated with the base material, the journal piece is cast and wrapped, the interface between the journal piece and the base material is reliably shielded from the outside of the cylinder block, and oil does not leak out. Furthermore, appropriate strength improvement can be obtained by the journal piece, and a cylinder block with excellent durability can be obtained.

It is a whole perspective view showing an outline of a cylinder of an engine. It is a perspective view showing an outline of a right cylinder block. It is explanatory drawing of a journal part, (a) is an III arrow line view which shows the principal part of FIG. 2, (b) is a bb sectional view taken on the line. It is explanatory drawing of a journal piece, (a) is a perspective view, (b) is b of (a). It is a schematic explanatory drawing of a casting type | mold, (a) is a principal part sectional view of a casting type | mold, (b) is a bb sectional view taken on the line of (a). It is a casting process chart It is casting process explanatory drawing, (a) is a principal part sectional view of a casting die, (b) is a bb line sectional view of (a). It is casting process explanatory drawing, (a) is a principal part sectional view of a casting die, (b) is a bb line sectional view of (a). It is casting process explanatory drawing, (a) is a principal part sectional view of a casting die, (b) is a bb line sectional view of (a). It is casting process explanatory drawing, (a) is a principal part sectional view of a casting die, (b) is a bb line sectional view of (a). It is casting process explanatory drawing, (a) is a principal part sectional view of a casting die, (b) is a bb line sectional view of (a).

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 11, taking a cylinder block of a horizontally opposed engine as an example.

  1 is a general perspective view showing an outline of a cylinder block of an engine, FIG. 2 is a perspective view of a cylinder block on the right side, FIG. 3 (a) is a III arrow view showing the main part of FIG. B) b) of FIG.

  The code | symbol 1 is a cylinder block of a horizontally opposed engine, and the cylinder block 1 has the structure which can be divided | segmented right and left centering | focusing on the central axis L of the crankshaft 5, and is integrally couple | bonded by the several joint bolt not shown. Be done.

  The left and right cylinder blocks 1A and 1B are separately cast formed of a light metal such as an aluminum-based alloy, in this embodiment, an aluminum-based alloy, and the left and right cylinder blocks 1A and 1B have cylinders shown in FIG. As shown in block 1 B, a plurality of journals 2 having a bearing surface 4 which is a concave surface formed in a semicircular arc shape at the center of a flat abutment surface 3 is formed.

  The crankshaft 5 is axially supported on the semicircular arc-shaped bearing surface 3 of each of the journal portions 2 opposed to each other by the left and right cylinder blocks 1A and 1B with a bearing metal 6 interposed therebetween. The crankshaft 5 is formed of an iron-based material, and is rotated by transmitting the reciprocating motion of the piston due to combustion of the air-fuel mixture in the cylinder through the connecting rod, and the journal portion 2 has a large impact during the rotation. Constant load and thermal expansion due to the propagation of heat from the combustion of the mixture.

  A journal piece 10 formed of an iron-based material, for example, an iron-based powder sintered body, is cast in the journal portions 2 of the left and right cylinder blocks 1A and 1B mainly for the purpose of strength improvement.

  The journal piece 10 has a semi-arc or U-shape extending along the central axis direction, as shown in a perspective view in FIG. 4A and a cross-sectional view taken along the line b-b in FIG. The flange portion 15 is integrally formed with the piece body 11 having the inner peripheral surface 12 and the outer peripheral surface 13 and the pair of opposing side surfaces 14 and extends in the radial direction at both ends of the piece body 11. The bolt holes 16 are drilled in the

  The inner peripheral surface 12 of the piece main body 11 has a substantially semicircular arc shape and a first inner peripheral surface 12a extending in the direction of the central axis, and a planar second connected continuously to one end of the first inner peripheral surface 12a. A fourth inner circumferential surface 12b, a third inner circumferential surface 12c continuous with the other of the first inner circumferential surface 12a, and a second inner circumferential surface 12b continuous with the other end of the third inner circumferential surface 12c It has an inner circumferential surface 12 d and a fifth inner circumferential surface 12 e.

  On the other hand, a convex portion 13 a having a pair of flat top surfaces 13 b extending in the radial direction is formed at the central portion of the outer peripheral surface 13. Further, a set pin hole 18 penetrating between the second inner circumferential surface 12 b and the outer circumferential surface 13 is bored. The bolt holes 16 and the set pin holes 18 are formed in parallel.

  The left cylinder block 1A and the right cylinder block 1B are substantially symmetrical, and the right cylinder block 1B will be described below, and the description of the left cylinder block 1A will be omitted.

  The die casting machine for casting the cylinder block 1 B includes a casting mold 30 composed of a lower mold 31 and an upper mold 41. The main part of the casting mold 30 will be described with reference to FIG.

  Fig.5 (a) is principal part sectional drawing of the casting mold 30 in a type | mold open state, (b) is a bb sectional view of (a).

  In the cavity surface 32 of the lower die 31, the shapes of the bearing surface shaping portion 35 and the contact surface 3 projecting into the cavity 45 are formed in a semicircular arc shape in cross section for shaping the shape of the bearing surface 4 of the journal portion 2. It has a journal portion shaping portion 33 provided with a pair of contact surface shaping portions 34.

  Each of the contact surface shaping portions 34 is provided with a bolt hole pin 36 which can be inserted into the bolt hole 16 formed in the flange portion 15 of the journal piece 10 and for forming a bolt hole in the journal portion 2. A step-like flange for contacting the lower surface 15a of the flange portion 15 near the base of the bolt hole pin 36 from the side of the journal shaping portion 33 to secure a gap between the journal portion 15 and the abutment surface shaping portion 35 The part contact part 36a is formed.

  In the bearing surface shaping portion 35, the tip end portion 37a can be inserted into the set pin hole 18 formed in the piece main body 11 of the journal piece 10 and abuts on the second inner circumferential surface 12b from the journal shaping portion 33 side. A cylindrical journal piece set pin 37 having a step-like piece contact portion 37b for determining the set position of the journal piece 10 is erected.

  The bolt hole pin 36 and the journal piece set pin 37 abut on the journal piece 10 to constitute a journal piece support for positioning and supporting the journal piece 10 at a desired position.

  On the other hand, in the upper mold 41, a cavity surface 42 for shaping the outer surface shape of the cylinder block 1B is formed. The cavity surface 42 has a bottomed cylindrical pressing member mounting hole 43 extending in the mold opening direction A so as to face each top surface 13 b of the journal piece 10 set in the lower mold 30. The holding member 20 is attached to the holding member mounting hole 43 in advance prior to casting of the journal piece 10.

  The pressing member 20 is made of an aluminum-based alloy which is the same kind of light metal as the cylinder blocks 1A and 1B, and extends coaxially with the base 20a and the base 20a which can be fitted or press-fitted into the pressing member mounting hole 43 It is formed in the axial body which has the position holding | maintenance part 20b which protrudes from the hole 43. As shown in FIG. The position holding portion 20b is installed in such a length that the top end 20c can abut on each top surface 13b of the journal piece 10 in a state where the journal piece 10 is set in the lower mold 31 and closed as described later. In addition, the outer periphery of the position holding portion 20b is subjected to surface area expansion processing in which it is formed into a bolt shape or a plurality of ring-shaped uneven surfaces.

  The process of casting the cylinder block 1B using the casting mold configured in this way will be described according to the process chart shown in FIG.

  In casting the cylinder block 1A, FIG. 5 (a) shows a cross-sectional view of the main part in the mold open state, and FIG. 5 (b) shows a cross-sectional view taken along line bb of (a). The base 20a is inserted into the formed pressing member mounting holes 43, and the positioning member 20 is mounted on the upper mold 41 (pressing member mounting step S1).

  Next, as shown in FIG. 7, each bolt hole 16 of the journal piece 10 and set from above on each of the bolt hole pins 36 and the journal piece set pins 37 erected on the journal portion forming portion 33 of the lower die 31. The pin hole 18 is inserted and the journal piece 10 is set in the lower die 31 (journal piece setting step S2).

  In the journal piece 10 set in the lower die 31, the lower surface 1 a of each flange portion 15 abuts on the flange portion abutting portion 36 a of the bolt hole pin 38, and the second inner circumferential surface 12 b is of the journal piece set pin 37. The flange portion 15 and the inner circumferential surface 12 of the journal piece 10 and the cavity surface 32, ie, the contact surface shaping portion 34 and the bearing surface shaping portion 35, are in contact with the piece contact portion 37b and positioned at a desired position. It is held in the expected state of separation distance.

  Next, as shown in FIG. 8, the upper mold 41 is moved close to the lower mold 31 in which the journal piece 10 is set, and the lower mold 31 and the upper mold 41 are put together to perform mold clamping (mold clamping process S3).

  In the mold clamping state in which the lower mold 31 and the upper mold 41 are put together and closed, the top end 20 c of each pressing member 20 provided on the cavity surface 42 of the upper mold 41 is the top surface of the convex portion 13 a of the journal piece 10 The journal piece 10 is held between the bolt hole pin 38 and the journal piece set pin 37 and the pressing member 20 provided on the cavity surface 42 of the upper mold 41 in abut on 13 b and fixed at the desired position in the cavity 45 It is held. At this time, the position holding portion 20 b of the pressing member 20 is exposed in the cavity 45.

  Subsequently, as shown in FIG. 9, the casting mold 30 formed by the lower mold 31 and the cavity faces 32 and 42 of the upper mold 41 with the light metal melt, ie, the aluminum-based alloy melt M, clamped from a hot water supply port not shown. Hot water filling is performed in the cavity 45 (hot water supply process S4).

  After the hot-water supply filling, the molten aluminum-based alloy molten metal is solidified while maintaining the mold-clamped state (solidifying step S5). At this time, the journal piece 20 is held between the bolt hole pin 36 formed on the lower mold 31, the journal piece set pin 37, and the top end 20c of the pressing member 20 protruding from the cavity surface 42 of the upper mold 41 Because it is fixed, it can be cast at the desired position without causing misalignment. On the other hand, the holding member 20, in particular, the position holding portion 20b exposed in the cavity 45 is melted and integrated by the molten aluminum alloy M filled in the cavity 45 with hot water. At this time, surface area expansion processing is performed in which the outer peripheral surface of the position holding portion 20b of the pressing member 20 is formed in a concavo-convex shape, and the contact area with the aluminum alloy molten metal M is widely formed. And it dissolves efficiently.

  Thus, as shown by a cross section along line b-b in (a) in FIGS. 10A and 10B, the lower surface 15a of the inner peripheral surface 12 of the journal piece 10 and the lower surface 15a of the flange portion 15 and the lower die 31 are shown. The molten aluminum alloy also flows into between the bearing surface shaping portion 35 and the abutting surface shaping portion 34, and the inner peripheral surface 12 of the journal piece 10 is covered with the aluminum alloy with a desired thickness, so that the journal piece The outer peripheral surface 13 of 10 is covered with the aluminum-based alloy containing the pressing member 20 which melt | dissolved.

  After the molten aluminum-based alloy injected into the cavity 45 of the casting mold 30 solidifies, the upper mold 41 is moved to the mold opening position shown by the phantom line 41a in FIG. 10 to separate the lower mold 31 and the upper mold 41 from each other. The mold opening is performed (mold opening step S6).

  The cylinder block 101 cast in the cavity 45 is taken out of the mold-opened casting mold 30 by, for example, a robot (product removal step S7).

  A mold release agent is spray-coated on the cavity faces 32 and 42 of the opened lower mold 31 and the upper mold 41 (mold release agent applying step S8). From the pressing member mounting step S1 for mounting the pressing member 20 to the casting mold 30 From the journal piece setting step S1 for setting the journal pin 10 to the casting mold 30 from the journal piece setting step S1 A cylinder block is cast sequentially by repeating each process to S8.

  The cylinder block 1B manufactured in this manner is held by the bolt hole pin 36 formed on the lower die 31 with the journal piece 20, the journal piece set pin 37, and the pressing member 20 attached to the cavity surface 42 of the upper die 41. The aluminum alloy molten metal M is supplied with hot water and cast in the cavity 45 in a state of being fixed and held in the predetermined position, and the pressing member 20 is melted by the aluminum alloy molten metal and integrated with the base material to be a journal piece By casting 10, the interface between the journal piece 10 and the base material is reliably cut off from the outer surface of the cylinder block 1B.

  As a result, the journal piece 10 is cast in the desired position, the desired balanced strength of the journal portion 2 by the journal piece 10 is obtained, and the bearing surface 4 of the journal portion 2 is held cylindrically with high accuracy Therefore, a decrease in the coefficient of friction with the rotating crankshaft 5 is obtained, oil consumption is suppressed, and wear of the crankshaft 5 and the journal portion 2 etc. is reduced, and the fuel efficiency, performance, durability, etc. of the engine are improved. Thus, vibration and noise are suppressed.

  Furthermore, the interface between the journal piece 10 and the base material does not communicate with the outer surface of the cylinder block 1A, and the oil from the bearing side to the interface between the journal piece 10 and the base material through the bolt hole formed in the journal Oil does not exude to the outside from the interface between the journal piece 10 and the base material even if it penetrates, contamination of the outer surface etc. of the cylinder block 1A with oil is avoided, and oil consumption is suppressed. Ru. In addition, air and moisture do not infiltrate into the interface between the journal piece 10 and the base material from the outside, and a reduction in the bonding strength of the portion is suppressed.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. For example, although the journal piece 10 is fixed to the lower mold 31 by the bolt hole pin 36 and the journal set pin 37 in the above embodiment, the journal piece support by other means such as forming a protrusion on the cavity surface 32 of the lower mold 31 The part can also hold the journal piece 10.

  In the above embodiment, the pressing member mounting hole 43 is formed to face the top surface 13b of the convex portion 13a formed on the outer peripheral surface 13 of the journal piece 10, but as shown in FIG. When the upper mold 41 is a casting mold in which the width direction of the journal piece 10 is the mold opening direction A, a cavity in which the pressing member mounting hole 43 is on the side of the convex portion 13b of the journal piece 10 set in the journal support portion. It is formed in a bottomed cylindrical shape extending in the mold opening direction A at the position of the surface 43. The pressing member 20 is inserted into or pressed into the pressing member mounting hole 43, and the pressing member 20 extends in the mold opening direction A, and the outer periphery of the journal piece contact portion 20b is closed with the journal piece 10 set in the lower die 31. The top surface 13 b of the journal piece 10 is disposed to be abuttable.

  Although the casting by this casting die is different from that of the above embodiment from the die opening direction A of the casting die, the casting process and the effects and the like of the cast cylinder block are substantially the same as the above embodiment. These descriptions are omitted.

DESCRIPTION OF SYMBOLS 1 cylinder block 2 journal portion 10 journal piece 11 piece main body 20 pressing member 20 a base portion 20 b position holding portion 30 casting mold 31 lower die 32 cavity surface 33 journal portion shaping portion 34 abutting surface shaping portion 35 bearing surface shaping portion 36 Bolt hole pin (journal piece support)
37 Journal Piece Set Pin (Journal Piece Support)
41 upper mold 42 cavity surface 43 pressing member mounting hole 45 cavity

Claims (4)

The lower surface of the cylinder block is provided with a lower mold provided with a journal piece support for positioning and supporting the journal piece in the cavity surface and the cavity in which the journal shaping section for shaping the journal of the cylinder block is formed. In a method of casting a light alloy cylinder lock according to the present invention, a journal piece of an iron-based material is cast in a journal portion using a casting mold having an upper mold having a forming cavity surface and
A light alloy pressing member mounted on the cavity face of the upper mold is brought into contact with the journal piece positioned by the journal piece support to hold the journal piece, and the light alloy is held in the cavity while holding the journal piece. A casting method for a cylinder block, characterized in that a molten metal is hot-water filled and cast to cast a cylinder block. A pressing member attaching step of attaching a pressing member capable of coming into contact with a journal piece that protrudes from the cavity surface and is positioned on the journal piece support portion on the cavity surface of the upper mold;
A journal piece setting step of setting the journal piece in the journal piece support;
A clamping step in which the pressing member is brought into contact with the journal piece set in the journal piece support portion to clamp the die;
A hot water supply process for hot-water filling of light alloy molten metal in the clamped cavity;
A solidification step of solidifying the light metal melt filled with the hot water supply while maintaining the mold clamping state;
The method for casting a cylinder block according to claim 1, further comprising: a lower mold and a mold opening process for separating the upper mold. The pressing member is in the form of a shaft including a base and a position holding portion integrally formed with the base,
The cavity surface of the upper mold has a recessed pressing member mounting hole,
The method according to claim 1 or 2, wherein the pressing member is mounted in a state where the base portion is inserted into the pressing member mounting hole and the position holding portion protrudes from the cavity surface.   The cylinder block casting method according to claim 3, wherein a surface area expansion process is performed on an outer periphery of the position holding unit.

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