JPH0619953U - Support structure for the soluble core of the piston - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a support structure for a soluble core of a piston capable of reliably holding the soluble core at an accurate position until the casting is completed. [Structure] Anti-wear ring (4) provided around ring groove (3A)
In the support structure of the fusible core (12) of the piston (1) fixed together in the mold for forming the cooling gallery, the fusible core (12) is supported by the support member (13) in the wear resistant ring (4). I tried to support it on the circumference.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a support structure for a fusible core of a piston, and more particularly to a support structure for a fusible core used for forming a cooling gallery when casting a piston.

[0002]

[Prior art]

 As a conventional supporting structure for a soluble core of a casting type piston, there is one disclosed in FIG. 5 in Japanese Patent Laid-Open No. 61-1446. In this conventional example, for example, a water-soluble salt core is used as a soluble core for forming a cooling cavity (gallery), and a cooling oil inlet / outlet port is formed to hold such a salt core in a mold. The core of the die-cast pin is used to support the core. For this reason, two support holes are formed in the core, and the tip of the die-cast pin is inserted into these support holes to form the entire core. Is supported in a hollow position in the mold.

[0003]

[Problems to be solved by the device]

 However, in the above-mentioned conventional example, supporting holes are provided in the core, and the tip of the casting pin is inserted into these to support the core. The cooling inlet / outlet is formed in the cooling cavity when the piston body is formed. Therefore, when inserting the casting pin into the support hole of the salt salt core forming an annular shape or when pouring, especially when using the molten metal forging method, the core may break at the support hole, or the core pin Get out of it and rise. Further, the core may be inclined with respect to the center line of the piston with respect to the two casting pins, so that the cooling cavity may not be properly formed at the normal predetermined position.

The object of the present invention is to solve the above-mentioned conventional problems, and in order to solve the problems, it is possible to surely hold the soluble core in a correct position until the casting is completed. It is to provide a support structure for the core.

[0005]

[Means for Solving the Problems]

 In order to achieve such an object, the present invention provides a support structure for a fusible core of a piston fixed in a mold for forming an annular gallery for cooling a crown portion together with an anti-wear ring provided along a ring groove. The soluble core is supported by the wear resistant ring by a supporting member.

[0006]

[Action]

 According to the present invention, the soluble core is supported by the wear resistant ring through the support member, so that it is not necessary to provide a supporting hole for supporting the soluble core, and thus the soluble core is easily broken. The core can be supported accurately in a stable state until the casting is completed.

[0007]

【Example】

 Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 shows an outline of a piston formed by applying the present invention. Here, 1 is a piston body, 2 is a ring portion in which a plurality of ring grooves 3 are formed, and 4 is a ring portion for improving wear resistance cast along the top ring groove 3A of the ring grooves 3. A ring 5 is a cooling cavity that is provided around the crown portion of the piston body 1 inside the ring 4, and cooling oil is introduced into the cooling cavity 5. However, the supporting structure of the salt core according to the present invention for forming the cavity 5 will be described in detail below. In addition, 6 is a piston pin hole, 7 is a pin boss part.

FIG. 2 shows a procedure for casting the piston body 1. As shown in (A), first, the outer die 10 for forming the outer peripheral portion of the piston is assembled with the material 4A of the wear resistant ring 4 for casting, the core die 11 for forming the piston pin hole, and the like. Next, a soluble core (salt core) 12 prepared in advance for forming the cooling cavity 5 is held between the ring carrier material 4A and the core support member 13 as shown in (B). I will let you.

FIG. 3 shows a supporting state by such a core supporting member 13. The core support member 13 is made of, for example, metal having elasticity. The elastic force is used to elastically support the salt core 12 between the outer periphery of the ring carrier material 4A. Therefore, the core support member 13 shown in FIG. As shown in (B), a plurality of connecting support portions 14 that are bidirectionally connected by the spring property formed over the salt core 12 and the ring carrier material 4A, and between these connecting portions 14 are further circumferentially arranged. It has a C-shaped annular portion 15 (see FIG. 3A) for connection. In this example, in order to keep the relatively brittle salt core 12 in good balance, such an annular portion 15 is provided on the salt core 12 side. As shown in FIG. 3 (B), the connecting and supporting portion 14 has a substantially U-shaped cross section, and one side (hereinafter referred to as a core supporting piece) 14A has a salt core 12. To facilitate holding, and the other side (hereinafter referred to as a fixed piece) 14B is formed into a shape fitted to the inner circumferential surface of the wear-resistant ring material 4A. The pieces 14A and 14B are connected by a connecting piece 14C.

Therefore, in the state where the salt core 12 is supported by the core supporting member 13 having an overall C-shape as described above, this is further utilized by utilizing the spring property of the connecting support portion 14. By fitting it on the inner peripheral surface of the ring-resistant material 4A, the state shown in FIG. 2B can be obtained. It should be noted that, in this figure, the separable core assembled around the core mold 11 is omitted for easy understanding. Then, as shown in FIG. 2 (C), the top part of the piston is closed by the mold 10A, and the molten metal for pouring is injected from the sprue 10B to obtain a finished unfinished body of the piston body. It

[0012] Therefore, after the cast iron body is taken out from the mold 10, as shown in FIG. 4, it is bored from the inside of the piston body 1 toward the salt core 12, and the bores 16 and 17 are bored. Is applied to the inlet and outlet of the cooling oil, and water is injected using these holes 16 and 17 to dissolve the core. Thus, with the cooling gallery 5 as shown in FIG. 1, it is possible to form an oil inlet / outlet port for the gallery 5, after which the piston outer diameter part including the cast ring-resistant material 4A is formed. The finishing process, the formation cutting of the ring groove 3, and the finishing process of the piston pin hole 6 may be performed. Although the core support member 13 is left inside the product, there is no exposed portion on the surface of the product, and it does not impair the function of cooling the cavity 5, which is a problem. There is no.

[0013]

[Effect of device]

 As described above, according to the present invention, the support structure for the soluble core of the piston which is fixed in the mold for forming the annular gallery for cooling the crown portion together with the wear resistant ring provided along the ring groove. In the above, since the soluble core is supported by the wear resistant ring by the support member, the salt core floats up when pouring, and the unstable support of the salt core by the conventional support pin is caused. It is possible to prevent displacement of the salt core due to the salt core coming off or tilting from the support pin, or damage to the salt core from the vicinity of the support hole provided in the salt core. In addition, the elimination of the cast pin contributes to the simplification of the structure of the entire die, and the cooling cavity can be formed at an accurate position.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of a piston formed by applying the present invention.

FIG. 2 shows the steps of assembling the mold according to the present invention (A) and (B).
It is explanatory drawing shown in three steps of and (C).

FIG. 3 is an explanatory view showing a salt core supporting state according to the present invention by a top view (A) and a sectional view (B) taken along line XX of (A).

FIG. 4 is an explanatory view showing the oil inlet / outlet drilling process according to the present invention as viewed from the lower surface side.

[Explanation of symbols]

 1 Piston Main Body 2 Ring Part 3 Ring Groove 3A Top Ring Groove 4 Abrasion Resistant Ring 4A Abrasion Resistant Material 5 Cooling Cavity (Gallery) 10 Outer Mold 11 Core Type 12 Soluble Core (Salt Core) 13 Core Support Member 14 Connection Support part 14A Core support piece 14B Fixed piece 14C Connection piece 15 Annular part 16,17 hole

Claims (2)

[Scope of utility model registration request] 1. A support structure for a fusible core of a piston, which is fixed in a mold for forming an annular gallery for cooling a crown part together with a wear resistant ring circumferentially provided along a ring groove, wherein the fusible core is a supporting member. A support structure for a fusible core of a piston, characterized in that the support ring is supported by the wear resistant ring. 2. The support member has a spring property and is formed at a plurality of positions equally divided in the circumferential direction so as to match the shapes of the inner peripheral portion of the wear resistant ring and the outer peripheral portion of the fusible core, respectively. The fusible core support structure for a piston according to claim 1, further comprising a connection support portion that is biased toward an inner peripheral portion of the wear resistant ring and an outer peripheral portion of the fusible core due to its spring property.