JP6292029B2 - Hollow wear-resistant ring for piston, piston for internal combustion engine, and method for manufacturing piston for internal combustion engine - Google Patents

Description

  The present invention can improve the inflow efficiency of lubricating oil into a hollow wear-resistant ring for pistons cast into a piston of an internal combustion engine, and a piston ring fitted into a piston ring groove on an outer peripheral wall of the hollow wear-resistant ring for pistons, and The present invention relates to a hollow wear-resistant ring for a piston capable of remarkably improving the cooling performance in the vicinity of a combustion chamber of the piston, a piston for an internal combustion engine, and a method for manufacturing the piston for the internal combustion engine.

  In a piston disposed in a cylinder (cylinder) of an internal combustion engine, a hollow through which piston lubricating oil for cooling the piston ring (top ring, second ring and oil ring) and the vicinity of the combustion chamber passes is manufactured. A hollow wear-resistant ring for pistons having a portion may be cast.

  As shown in FIG. 6, the hollow wear-resistant ring 10X for the piston is composed of a wear-resistant annular body 11 made of Ni-resist cast iron in an annular shape by bending or the like, and a U-shaped cross section in which the outer peripheral side is opened by bending a stainless steel plate or the like The hollow annular body 12 is separately manufactured so that the upper side wall 12u and the lower side wall 12d having a U-shaped cross section are flush with the upper side wall 11u and the lower side wall 11d of the wear-resistant annular body 11. For example, the outer peripheral portion 12o of the hollow annular body 12 is joined to the inner peripheral wall 11i of the wear-resistant annular body 11 by, for example, Tig welding W or the like. The hollow portion 12c formed by the inner peripheral wall 11i of the wear-resistant annular body 11 and the concave portion of the U-shaped hollow annular body 12 circulates the lubricating oil O for cooling the vicinity of the piston combustion chamber and the wear-resistant annular body 11. The piston ring groove 11 a is formed in the outer peripheral wall 11 o of the wear-resistant annular body 11.

  Supplying the cooling lubricating oil O to the hollow portion 12c is performed by forming an inflow hole 12h and an outflow hole 12j communicating with the hollow portion 12c in the hollow annular body 12 by aluminum drilling or the like after casting the piston. Lubricating oil O injected by an oil jet disposed in the vicinity of an oil pan below the piston is introduced from an inflow hole 12h through an oil passage formed therein, passes through the hollow portion 12c, and passes through the outflow hole. This is done by returning the oil pan from 12j.

  Various techniques have been proposed as techniques for improving the cooling performance of this hollow wear-resistant ring for pistons.For example, the base end of each end of the upper plate and the lower plate made of austenitic stainless steel plate is made of anti-wear made of Ni-resist cast iron. With a cooling cavity that is integrally formed with the upper plate and the lower plate on the back surface of the wear-resistant ring by joining to the surface of the ring and joining the tip of each other end of the upper plate and the lower plate A wear-resistant ring has been proposed (see, for example, Patent Document 1).

  Also, a cylinder ring part having a piston ring groove, in which coolant is circulated by a molded body having a substantially U-shaped cross section formed by rolling a thin stainless steel, separately from a wear resistant ring main body part made of a cast resist material. An engine piston wear-resistant ring is proposed in which the molded body is joined to the wear-resistant ring main body portion by a nickel brazing material (see, for example, Patent Document 2).

  However, in the piston hollow wear-resistant ring 10X as shown in FIG. 6 of the prior art, the inflow efficiency of the lubricating oil O into the hollow portion 12c of the hollow annular body 12X formed in the hollow annular body having a U-shaped cross section. When the supply pressure of the lubricating oil O supplied to the inside of the hollow portion 12c from the inflow hole 12h is increased so as to improve the flow rate, as shown in FIG. Since it hits 12u at a high speed and is rebounded, most (for example, more than half) returns to the lower oil pan as it is from the inflow hole 12h, so that there is a problem that the cooling performance by this lubricating oil O cannot be improved.

  If this cooling performance is insufficient, the heat load increases, and the scuffs (scratches) due to adhesive wear on the sliding surface due to local metal contact due to cracks in the piston combustion chamber and oil film breakage occur in the rings, pistons and cylinders, In severe cases, the piston may be totally lost.

  In this connection, as a piston ring and combustion chamber cooling mechanism, in a piston for an internal combustion engine in which a cooling channel is formed inside the piston and oil is injected from an oil jet below the piston toward the inlet of the cooling channel. A piston for an internal combustion engine has been proposed in which a guide wall is provided on the ceiling of the cooling channel above the inlet so as to direct the direction of the flow of oil entering from the inlet in the direction in which the cooling channel is formed (see, for example, Patent Document 3). .

  In aluminum cooling channel pistons, cast iron pistons, etc., the guide wall is provided on the ceiling of the cooling channel, such as the piston for internal combustion engines, because molding with salt cores, sand cores, lost wax, etc., when pistons are cast You can do it.

  However, if it is intended to apply to a piston that casts a hollow wear-resistant ring for pistons, in the prior art, in the process of casting the hollow wear-resistant ring for pistons, the positioning of the hollow wear-resistant ring for pistons in the axial direction is the hollow wear-resistant ring for pistons. This is done by the V-shaped groove formed on the outer peripheral wall of the ring's wear-resistant annular body, but the positioning of the piston's hollow wear-resistant ring in the circumferential direction is not necessary, so the piston's hollow wear-resistant ring is cast and integrated. Then, after the piston is cast, the circumferential position of the guide wall is not known, and the inflow hole cannot be formed at a position facing the guide wall.

  Therefore, the idea of providing a guide wall in the piston that casts the hollow wear-resistant ring for the piston does not occur, and the amount of lubricating oil flowing in from the inflow hole formed in the lower side wall of the cooling hollow annular body is increased. The problem of improving the cooling performance of the hollow wear-resistant ring for pistons remains.

JP 2005-36771 A JP-A-5-231539 JP 2005-90448 A

  The present invention has been made in view of the above, and an object of the present invention is to increase the circulation amount of the lubricating oil to the hollow wear-resistant ring for the piston in the piston in which the hollow wear-resistant ring for the piston is cast, The cooling performance for the piston ring part and the vicinity of the combustion chamber is remarkably improved, and the piston temperature near the top surface of the piston, the combustion chamber, and the top ring groove can be lowered, cracks in the combustion chamber, ring scuffing, It is an object to provide a hollow wear-resistant ring for a piston, a piston for an internal combustion engine, and a method for manufacturing the piston for the internal combustion engine that can suppress the occurrence of piston scuff and the like.

  In order to achieve the above object, the hollow wear-resistant ring for pistons of the present invention includes a wear-resistant annular body in which a piston ring groove is formed in an outer peripheral wall after being cast into a piston of an internal combustion engine, and a cross section is opened on the outer peripheral side. A hollow for a piston having a U-shaped shape, and a portion on the outer peripheral side joined to an inner peripheral wall of the wear-resistant annular member, and a hollow annular member that forms a hollow portion through which cooling lubricating oil flows. In the wear ring, an engagement hole for positioning in the circumferential direction at the time of casting of the piston is formed in the wear ring or the hollow ring, and lubricating oil to be injected into the hollow part is formed in the hollow part. The guiding projection for guiding is formed at a portion of the hollow portion facing the lubricating oil inflow hole.

  According to this configuration, when the piston is cast by casting the hollow wear-resistant ring for the piston, the knock pin provided with the engagement hole such as the pin hole formed in the wear-resistant annular body or the hollow annular body is provided in the piston casting mold. By engaging with the engaging projections such as the like, the circumferential positioning of the piston hollow wear-resistant ring in the piston can be performed, and the guiding projection in the piston can be positioned.

  Therefore, by positioning the position of the guide protrusion at a position opposite to the inflow hole formed after the piston is cast to circulate the lubricating oil for cooling by the piston, Opposing inflow holes can be easily drilled in the lower wall of the cooling hollow annular body.

  As a result, in the piston in which the piston hollow wear ring is cast, the circulation amount of the lubricating oil to the piston hollow wear ring can be increased, and the cooling performance for the piston ring part and the vicinity of the combustion chamber can be remarkably improved. The piston temperature around the top surface of the piston, around the combustion chamber, and in the vicinity of the top ring groove can be lowered, and the occurrence of cracks in the combustion chamber, ring scuffing, piston scuffing, etc. can be suppressed.

  In the above hollow wear-resistant ring for piston, when the engagement hole is formed inside the region of the outer peripheral wall of the wear-resistant annular body where the piston ring groove is formed, the engagement hole is formed after casting the piston. Since the piston ring groove is formed in the outer peripheral wall of the wear-resistant annular body including the above-mentioned position, no engagement hole remains in the outer peripheral wall of the wear-resistant annular body, and therefore the durability of the wear-resistant annular body is maintained without deteriorating. be able to.

  Moreover, the piston of the internal combustion engine of this invention for achieving said objective is comprised by casting the said hollow wear-resistant ring for pistons, and there can exist the same effect as said hollow wear-resistant ring for pistons.

  In addition, the method of manufacturing a piston of an internal combustion engine of the present invention to achieve the above object is to provide a wear-resistant annular body in which a piston ring groove is formed in an outer peripheral wall after being cast into the piston of the internal combustion engine. An annular body production process, and a hollow annular body production process that produces a hollow annular body that forms a hollow portion in which a cross-sectional shape is U-shaped with an outer peripheral side opened and cooling lubricant flows; Forming a guiding projection for guiding the lubricating oil injected into the hollow portion into the hollow portion into the hollow portion at a portion of the hollow portion facing the planned drilling position of the lubricating oil inflow hole. A step of forming an engagement hole for positioning in the circumferential direction in the wear-resistant annular body or the hollow annular body, and an outer peripheral side of the hollow annular body on the inner circumferential wall of the wear-resistant annular body. Including the joining process of joining the parts in any order. Further, the axial position of the hollow wear-resistant ring for pistons is aligned with the piston mold, and the engagement hole for circumferential positioning of the hollow wear-resistant ring for pistons is used for the circumferential positioning of the piston mold. A casting step of casting the piston in accordance with the mating protrusion, and forming an outflow hole for the cooling lubricant and an inflow hole for the cooling lubricant in the piston taken out from the piston mold It is a method characterized by including a hole forming step for forming the piston ring groove by removing a region where the piston ring groove is formed, and a step for forming the piston ring groove.

  Further, in the method for manufacturing a piston of the internal combustion engine, the engagement hole is formed in a region where the piston ring groove is formed in the outer peripheral wall of the wear-resistant annular body.

  According to these methods, it is possible to provide a piston for an internal combustion engine that further improves the piston cooling efficiency of the hollow wear-resistant ring described above.

  According to the piston hollow wear-resistant ring of the present invention, the piston of the internal combustion engine, and the piston manufacturing method of the internal combustion engine, in the piston in which the piston hollow wear-resistant ring is cast, It can be increased, the cooling performance for the piston ring part and the combustion chamber vicinity part can be remarkably improved, the piston top surface, around the combustion chamber, the piston temperature in the vicinity of the top ring groove can be lowered, the crack of the combustion chamber, Generation of ring scuffing and piston scuffing can be suppressed.

It is a perspective view containing the cross section which shows typically the structure of the hollow wear-resistant ring for pistons of embodiment which concerns on this invention. It is a figure which shows an example of the flow of the manufacturing process of the piston of the internal combustion engine of embodiment which concerns on this invention. It is a figure which shows the formation method of a guidance protrusion part. It is a figure which shows joining of a wear-resistant annular body and the annular body for hollows. It is a figure for demonstrating the mode of inflow of the lubricating oil for cooling to the hollow part of the hollow wear-resistant ring for pistons when there exists a guidance protrusion part. It is a perspective view containing the cross section which shows typically the structure of the hollow wear-resistant ring for pistons of a prior art. It is a figure for demonstrating the mode of inflow of the lubricating oil for cooling to the hollow part of the hollow wear-resistant ring for pistons of a prior art.

  Hereinafter, a hollow wear-resistant ring for a piston, a piston for an internal combustion engine, and a method for manufacturing the piston of the internal combustion engine according to embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a hollow wear-resistant ring 10 for a piston according to this embodiment is embedded in a piston of an engine (internal combustion engine) 1, and includes a wear-resistant annular body 11 and a hollow annular body 12. Composed.

  The wear-resistant annular body 11 is manufactured by forming Niresist cast iron into an annular body by casting, inner and outer peripheral surface processing, and the like, and after being encased in a piston, a piston ring groove 11a is formed in the outer peripheral wall 11o by machining such as cutting. The In this wear-resistant annular body 11, the positioning V-shaped groove 11 v in the axial direction (piston height direction) of the piston hollow wear-resistant ring 10 when being cast into the piston as the piston hollow wear-resistant ring 10 is formed at the time of casting of the resist. Produced by processing.

  Further, the hollow annular body 12 is produced by bending a stainless steel plate or the like into a U-shaped annular body having a cross section opened on the outer peripheral side, and the outer peripheral side portion 12 o is formed in the wear-resistant annular body 11. By joining to the peripheral wall 11i by Tig welding W etc., the hollow part 12c through which the lubricating oil O for cooling flows is formed. The hollow annular body 12 is manufactured separately from the wear-resistant annular body 11, and the upper wall 12 u and the lower side wall 12 d of the U-shaped cross section of the hollow annular body 12 are both the upper wall 11 u and the wear-resistant annular body 11. Produced to be flush with the lower side wall 11d.

  Further, in the hollow wear-resistant ring 10 for piston of the present invention, a dimple hole (engagement hole) 21 for positioning in the circumferential direction at the time of casting of the piston is further formed in the wear-resistant annular body 11 or the hollow annular body 12. To do. The dimple hole 21 is provided in the upper side wall 11u or the lower side wall 11d of the wear-resistant annular body 11 or the upper side wall 12u or the lower side wall 12d of the hollow annular body 12, or the depression of the guide protrusion 20 is used. However, it is preferably provided on the outer peripheral wall 11o of the wear-resistant annular body 11 that is not cast at the time of casting, and particularly preferably in the region where the piston ring groove 11a is formed.

  At the same time, in the hollow annular body 12, the guide protrusion 20 that guides the lubricating oil O injected into the hollow portion 12 c into the hollow portion 12 c is provided at a portion facing the inflow hole 12 h of the lubricating oil O in the hollow portion 12 c. Form.

  The dimple hole 21 is preferably formed inside the region where the piston ring groove 11a is formed, so that the outer peripheral wall of the wear-resistant annular body 11 includes the position where the dimple hole 21 is formed after casting the piston. Since the piston ring groove 11a is formed in 11o, the dimple hole 21 does not remain on the outer peripheral wall 11o of the wear-resistant annular body 11, so that the normal formation of the piston ring groove, the durability deterioration of the wear-resistant annular body 11 and the piston crack, etc. Durability can be maintained without causing the occurrence of.

  Here, the effect by forming the induction | guidance | derivation protrusion part 20 in the site | part facing the inflow hole 12h of the lubricating oil O of the hollow part 12c is demonstrated. As shown in FIG. 1, lubricating oil O injected from an oil jet (not shown) disposed in the vicinity of an oil pan (not shown) below the piston is used as an inflow oil passage (not shown) formed in the piston. ) Through an inflow hole 12h formed in the lower wall 12d of the hollow annular body 12 of the hollow wear-resistant ring 10 for piston. As a result, the lubricating oil O makes a half turn inside the hollow portion 12c and is discharged from the outflow hole 12j to the oil pan through a discharge oil passage (not shown). The circumference of the wear-resistant annular body 11 and the piston hollow wear-resistant ring 10 is cooled while making a half turn inside the hollow portion 12c of the lubricating oil O.

  As shown in FIG. 5, the lubricating oil O supplied to the hollow portion 12c from the inflow hole 12h collides with the side surface of the guide projection portion 20, and thus flows in the circumferential direction of the hollow portion 12c. As a result, as shown in FIG. 7, there is no guide projection 20 and most of the lubricating oil O can be prevented from returning from the inflow hole 12h, so the flow rate of the lubricating oil O that makes a half turn inside the hollow portion 12c is increased. be able to. Accordingly, the amount of lubricating oil O flowing into the piston hollow wear-resistant ring 10 can be increased to improve its cooling performance.

  The piston of the internal combustion engine according to the embodiment of the present invention includes the piston hollow wear-resistant ring 10 according to the embodiment of the present invention.

  Next, a method for manufacturing a piston for an internal combustion engine according to an embodiment of the present invention will be described with reference to FIG. This piston manufacturing method for an internal combustion engine includes a piston hollow wear-resistant ring production process (S11) for producing a piston hollow wear-resistant ring 10, a casting process (S12), and a hole and groove machining process (S13). Consists of.

  This piston hollow wear-resistant ring production process (S11) includes a wear-resistant annular body production process, a hollow annular body production process, a guide projection forming process, an engagement hole forming process, and a joining process in any order. Contains.

  This wear-resistant annular body production process is a process for producing a wear-resistant annular body 11 by forming Ni-resist cast iron in which a V-shaped groove 11v is formed at the time of casting into an annular body by casting, inner and outer peripheral surface processing, and the like. This wear-resistant annular body 11 is cast into the piston of the internal combustion engine in the casting step (S12), and then in the hole and groove processing step (S13), the piston ring groove 11a is formed in the outer peripheral wall 11o. In the annular body production process, a V-shaped groove 11v for axial positioning when the hollow wear-resistant ring for piston 10 is cast into the piston is formed on the outer peripheral wall 11o of the abrasion-resistant annular body 11.

  The hollow annular body production step is a step of producing the hollow annular body 12 by bending a stainless steel plate or the like into a U-shaped annular body having a cross section opened on the outer peripheral side. In this hollow annular body production process, the upper side wall 12u and the lower side wall 12d of the U-shaped cross section of the hollow annular body 12 are both flush with the upper side wall 11u and the lower side wall 11d of the wear resistant annular body 11. Produced. Usually, the upper side wall 12u and the lower side wall 12d are formed in parallel.

  In the guiding projection forming step, the guiding projection 20 for guiding the lubricating oil O injected into the hollow portion 12c into the hollow annular body 12 into the hollow portion 12c is formed in the inflow hole 12h of the lubricating oil O in the hollow portion 12c. For example, as shown in FIG. 3, the hollow annular body 12 is installed in a press mold 30 and pressed from above with a mold press in the P direction. The convex guide protrusion 20 is formed by pressing or the like.

  The position of the guide protrusion 20 is an arbitrary position with respect to the circumferential direction of the upper side wall 12u of the cooling hollow annular body 12, and is a substantially central position with respect to the radial direction. If the upper wall 12u of the position 12p1 is formed as a convex wall toward the hollow portion 12c, the shape of the guide protrusion 20 may be a V-shaped groove. However, as shown in FIG. It is sufficient that the lubricating oil can be guided in the circumferential direction by receiving the jet of oil O, and may have other shapes.

  The guide protrusion forming step may be performed before the hollow annular body 12 is formed in a U-shaped cross section, but after the hollow annular body 12 is formed in the U-shaped cross section. Preferably, it is formed by pressing or the like before joining to the wear-resistant annular body 11, and in this case, the upper wall 11u and the lower side wall 11d of the wear-resistant annular body 11 are kept in parallel with the upper side wall 12u and the lower side wall 12d. It becomes easy to keep even.

  If the guide projection 20 is formed after the hollow annular body 12 and the wear-resistant annular body 11 are joined to form the hollow wear-resistant ring 10 for the piston, it is used when the guide projection 20 is formed. Due to the impact force, the parallelism of the upper side wall 12u and the lower side wall 12d of the hollow annular body 12 may be broken.

  The engagement hole forming step is a step of forming dimple holes (engagement holes) 21 for circumferential positioning in the wear-resistant annular body 11 or the hollow annular body 12. In FIG. 4, the dimple hole 21 is formed by drilling or the like inside the region where the piston ring groove 11 a of the outer peripheral wall 11 o of the wear-resistant annular body 11 is formed. Since the relationship between the position of the dimple hole 21 and the position of the guide projection 20 in the circumferential direction of the hollow annular body 12 is an important clue for determining the oil hole machining portion 12h, the dimple hole 21 and the guide projection in the circumferential direction are previously provided. The setting position of the unit 20 is determined in advance. For example, the circumferential angle of the dimple hole 21 and the guide projection 20 in the circumferential direction is made the same and the like is clarified.

  The circumferential position determining dimple hole (engagement hole) 21 is provided on the upper side wall 11u or the lower side wall 11d of the wear-resistant annular body 11 or on the upper side wall 12u or the lower side wall 12d of the hollow annular body 12 or guided. However, in any case, since it is in a place where casting is performed, it is necessary to move the knock pin 22 after casting before positioning. Therefore, it is preferably provided in the outer peripheral wall 11o of the wear-resistant annular body 11 that is not cast at the time of casting, and particularly in the region where the piston ring groove 11a is formed.

  Further, in the joining step, as shown in FIG. 4, the outer circumferential side portion 12o of the hollow annular body 12 is joined to the inner circumferential wall 11i of the wear resistant annular body 11 by Tig welding W or the like, so that the piston hollow abrasion resistant ring 10 is formed. It is a production process.

  In the next casting step (S12), the axial position of the piston hollow wear-resistant ring 10 is aligned with the piston mold, and the dimple hole 21 for positioning the piston hollow wear-resistant ring 10 in the circumferential direction is replaced with the piston mold (piston casting). The piston is cast in accordance with a knock pin (engagement protrusion) 22 for determining the circumferential position of the casting mold.

  In this casting process, before placing the piston hollow wear-resistant ring 10 in the piston mold, the piston hollow wear-resistant ring 10 is immersed in a molten metal similar to the metal used for the piston (for example, an aluminum alloy). Then, this metal coating (aluminum bonding layer in the case of using an aluminum alloy) is formed on the entire piston hollow wear-resistant ring 10. By forming the metal coating, when the piston hollow wear ring 10 is cast and the piston is cast, the wettability between the piston hollow wear ring 10 and the piston can be improved. The hollow wear-resistant ring 10 can be easily cast.

  Next, although not particularly illustrated, a single or a plurality of piston hollow wear-resistant rings 10 are arranged in a mold sandwiched from the outer peripheral side of a piston mold (outer mold), and first, for each piston. The axial positioning of the hollow wear-resistant ring 10 and the inclination of the shaft of the hollow wear-resistant ring 10 for pistons are determined by the axial positioning at a plurality of positions. This axial positioning or the like can be performed by supporting the V-shaped groove 11v of the outer peripheral wall 11o of the wear-resistant annular body 11 with a pointed protrusion provided on the piston mold side.

  Then, after performing this axial positioning and the like, with a pointed protrusion inserted into the V-shaped groove 11v, the piston hollow wear-resistant ring 10 is positioned in the circumferential direction of the piston hollow wear-resistant ring 10 with respect to the piston mold. In a supported state, the knock pin 22 provided on the piston mold is rotated in the circumferential direction with respect to the piston mold until the knock pin 22 is engaged with the dimple hole 21 of the piston hollow wear-resistant ring 10. Positioning in the circumferential direction is completed by engaging the knock pin 22 with the dimple hole 21. Note that a single pair of knock pins 22 and dimple holes 21 may be used, but a plurality of pairs may be used.

  After each positioning of these piston hollow wear-resistant rings 10, a molten metal (for example, an aluminum alloy) used as a piston material is poured into the piston mold. After cooling and solidifying, the cast piston is taken out from the piston mold.

  In the hole and groove machining step (S13), a cooling lubricant O inflow passage (not shown) and an inflow hole 12h communicating with the cooling oil O are drilled into the piston taken out from the piston mold. And a cooling oil O outflow passage (not shown) and an outflow hole 12j are simultaneously drilled. The inflow hole 12h needs to be formed at a portion facing the guide protrusion 20, but the position of the guide protrusion 20 can be specified by engaging the knock pin 22 with the dimple hole 21, so the inflow hole 12h can be easily formed. It can be formed at a portion facing the guide protrusion 20.

  At the same time, a region where the piston ring groove 11a is formed is deleted by cutting or the like to form the piston ring groove 11a. As shown in FIG. 4, if the dimple hole 21 is included in the area to be deleted, the trace of the dimple hole 21 does not remain after the piston ring groove 11 a is formed. Can be avoided.

  In addition to the formation of the piston ring groove 11a, finishing processing such as pin hole (not shown) processing on the piston and formation of a metal coating (for example, tin) on the surface of the piston is performed. When this finishing process is finished, the production of the piston is finished.

  The above-described method for manufacturing a piston of an internal combustion engine includes a wear-resistant annular body production process for producing a wear-resistant annular body 11 in which a piston ring groove 11a is formed in an outer peripheral wall 11o after being cast into the piston of the internal combustion engine, A hollow annular body production process for producing a hollow annular body 12 having a U-shaped shape with an outer peripheral side opened and forming a hollow portion 12c through which cooling lubricant O flows, and a hollow annular body 12 The guide projection 20 for guiding the lubricating oil O injected into the hollow portion 12c into the hollow portion 12c is formed at a portion of the hollow portion 12c facing the planned drilling position of the inflow hole 12h of the lubricating oil O. A forming step, an engagement hole forming step of forming a dimple hole (engagement hole) 21 for positioning in the circumferential direction in the wear-resistant annular member 11 or the hollow annular member 12, and a hollow for the inner peripheral wall 11i of the wear-resistant annular member 11 The outer peripheral part of the annular body 12 And a bonding step of bonding a 12o in arbitrary order.

  At the same time, the axial position of the piston hollow wear-resistant ring 12 is aligned with the piston mold, and the dimple hole 21 for positioning the piston hollow wear-resistant ring 12 in the circumferential direction is used for circumferential positioning of the piston mold. A casting process for casting a piston in accordance with the knock pin 22, and an outflow hole 12j for cooling lubricating oil O is formed in the piston taken out from the piston mold, and an inflow hole 12h for lubricating oil O for cooling is guided. It includes a hole and groove processing step that is formed in a portion facing the protruding portion 20 and that deletes the region where the piston ring groove 11a is formed to form the piston ring groove 11a.

  According to the piston hollow wear-resistant ring 10 of the above configuration, the piston of the internal combustion engine, and the piston manufacturing method of the internal combustion engine, the wear-resistant annular body 11 is formed when the piston hollow wear-resistant ring 10 is cast and the piston is cast. By positioning a dimple hole (engagement hole) 21 formed in the outer peripheral wall 11o of the outer peripheral wall 11o with a knock pin (engagement protrusion) 22 provided in the piston mold, the circumferential position of the piston hollow wear-resistant ring 10 in the piston is determined. And the guide protrusion 20 in the piston can be positioned.

  Accordingly, the guide protrusion 20 is positioned at a position facing the inflow hole 12h for circulating the cooling lubricating oil O by the piston, which is formed after the piston is cast. The inflow hole 12h facing the protrusion 20 can be easily drilled in the lower side wall 12d of the hollow annular body 12.

  As a result, in the piston in which the hollow wear-resistant ring 10 for the piston is cast, the circulation amount of the lubricating oil O to the hollow wear-resistant ring 10 for the piston can be increased, and the cooling performance for the piston ring portion and the vicinity of the combustion chamber is remarkably improved. Thus, the piston temperature near the top surface of the piston, around the combustion chamber, and in the vicinity of the top ring groove can be reduced, and the occurrence of cracks in the combustion chamber, ring scuffing, piston scuffing, etc. can be suppressed.

  Further, when the dimple hole (engagement hole) 21 is formed inside the region where the piston ring groove 11a is formed, after the piston is cast, the position of the wear resistant annular body 11 including the position where the dimple hole 21 is formed is included. Since the piston ring groove 11a is formed in the outer peripheral wall 11o, no trace of the dimple hole 21 remains on the outer peripheral wall 11o of the wear-resistant annular body 11. Therefore, the durability of the wear-resistant annular body 11 can be maintained without deteriorating.

  The piston ring groove 11a is a groove for fitting a piston ring corresponding to the top ring, the second ring, and the oil ring. However, the piston ring groove 11a for the top ring is close to the combustion chamber and particularly requires cooling. Therefore, the wear-resistant annular body 11 having high cooling performance is particularly effective when used for a top ring.

10 Piston hollow wear-resistant ring 11 Wear-resistant annular body 11a Piston ring groove 11i Wear-resistant annular body inner peripheral wall 11o Wear-resistant annular body outer peripheral wall 11d Wear-resistant annular body lower wall 11u Wear-resistant annular member upper wall 12 Hollow annular member 12c Hollow part 12d Lower side wall 12u of hollow annular body Upper side wall 12h of hollow annular body Inflow hole 12j Outflow hole 20 Guiding protrusion 21 Dimple hole (engagement hole)
22 Knock pin (engagement protrusion)
30 Die for pressing W Tig weld P Press direction O Lubricating oil

Claims (5)

A wear-resistant annular body in which a piston ring groove is formed in an outer peripheral wall after being cast into a piston of an internal combustion engine, and a U-shaped cross section with an outer peripheral side open. In a hollow wear-resistant ring for a piston comprising a hollow annular body that is joined to the inner peripheral wall of the annular body and forms a hollow portion through which cooling lubricating oil flows,
While forming an engagement hole for circumferential positioning at the time of casting of the piston in the wear-resistant annular body or the hollow annular body,
A hollow wear-resistant ring for pistons, wherein a guide projection for guiding the lubricating oil injected into the hollow portion into the hollow portion is formed at a portion facing the lubricating oil inflow hole of the hollow portion.   2. The hollow wear-resistant ring for piston according to claim 1, wherein the engagement hole is formed in a region of the outer peripheral wall of the wear-resistant annular body where the piston ring groove is formed.   A piston for an internal combustion engine, wherein the hollow wear-resistant ring for a piston according to claim 1 or 2 is cast. A wear-resistant annular body production process for producing a wear-resistant annular body in which a piston ring groove is formed in an outer peripheral wall after being cast into a piston of an internal combustion engine,
A hollow annular body production process for producing a hollow annular body having a hollow shape in which a cross-section is formed in a U shape with an outer peripheral side opened and a cooling lubricating oil flows,
Forming a guiding projection for guiding the lubricating oil injected into the hollow portion into the hollow portion into the hollow portion at a portion of the hollow portion facing the planned drilling position of the lubricating oil inflow hole. Process,
An engagement hole forming step of forming an engagement hole for circumferential positioning in the wear-resistant annular body or the hollow annular body;
A joining step of joining the outer peripheral side portion of the hollow annular body to the inner circumferential wall of the wear-resistant annular body in a random order;
The axial position of the hollow wear-resistant ring for pistons is aligned with the piston mold, and the engaging hole for positioning in the circumferential direction of the hollow wear-resistant ring for pistons is engaged with the engaging protrusion for positioning in the circumferential direction of the piston mold. A casting step of casting the piston in accordance with the portion, and a cooling lubricant outflow hole is formed in the piston taken out from the piston mold, and a cooling lubricant inflow hole is formed in the guide protrusion. A method of manufacturing a piston for an internal combustion engine, comprising: forming a piston ring groove by removing an area where the piston ring groove is formed, and forming a piston ring groove at a portion facing the portion.   5. The method of manufacturing a piston for an internal combustion engine according to claim 4, wherein the engagement hole is formed inside a region of the outer peripheral wall of the wear-resistant annular body where the piston ring groove is formed.

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