JPH0686845U - Core pin for mold - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to an improvement of a core pin incorporated in a cavity and fitted into a pin hole facing the cavity. A pin core 6 for a die is held by a holding part 11 of a sliding die 4 and is fitted into a pin hole 6a formed in a protrusion 6 in a cavity 5 as a die core pin 12.
a fitting portion 12a that can be fitted to a and the loose hole 1 of the holding portion 11
An intermediate shaft portion 12b for loosely inserting 1a and a base end portion 12c for loosely fitting in the large diameter hole 11b of the holding portion 11 are provided. Then, the base end side end surface T of the base end portion 12c is formed into a protruding spherical shape, and the base end side end surface T is brought into contact with the flat bottom surface H of the large diameter hole 11b.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a core pin incorporated in a cavity and fitted into a pin hole facing the cavity.

[0002]

[Prior art]

 Conventionally, for example, when forming a tunnel-shaped hole in a protrusion of a cast product having a complicated uneven surface shape, a core pin may be used during casting. That is, for example, as shown in FIG. 3, cavities 53 are formed on the mating surfaces of the fixed die 51 and the movable die 52, and a plurality of cavities 53 are formed from the cavity surface of the fixed die 51 or the movable die 52 toward the inside of the cavity 53. The protruding portion 54 is provided in a protruding manner. A pin hole 54a is formed in the protrusion 54 in the horizontal direction. Further, this mold is provided with a sliding mold 55 which is slidable in the lateral direction with respect to the fixed mold 51 and which comprises a main body portion 56 and a holding portion 57, and a core is provided in front of the holding portion 57. A pin 58 is attached. The core pin 58 can be fitted in the pin hole 54a of the protrusion 54 in a skewered shape. First, when the sliding die 55 is in the retracted position, the movable die 52 is moved to clamp the die, and Then, the sliding die 55 is moved forward to fit the core pin 58 into the pin hole 54a, and the molten metal is poured. When the casting is completed, the sliding die 55 is first retracted to release the engagement state between the core pin 58 and the pin hole 54a, the movable die 52 is opened, and the cast product is taken out. A tunnel-shaped hole is formed.

[0003]

[Problems to be solved by the device]

 However, the plurality of thin-walled protrusions 54 may have different thicknesses and the like, and the center of the pin hole 54a may be displaced or displaced due to a difference in thermal expansion. If the core pin 58 is forcibly inserted into the pin hole 54a with the center position deviated, there is a problem that it interferes with the protrusion 54 and an excessive force is applied, which eventually leads to breakage. It was

[0004]

[Means for Solving the Problems]

 In order to solve such a problem, the present invention is a fitting part that is held by a holding part of a mold and can be fitted into the pin hole as a mold core pin that can be fitted into a pin hole facing the inside of the cavity. An intermediate shaft portion that loosely inserts the loose hole of the holding portion, and a base end portion that loosely fits in the large diameter hole of the holding portion are provided. Then, the base end side end surface of the base end portion was formed into a convex shape, and the base end side end surface was brought into contact with the flat bottom surface of the large diameter hole.

[0005]

[Action]

 By making the end face on the base end side that abuts the flat bottom surface of the large-diameter hole a convex shape and allowing the intermediate shaft part to move freely, the axial direction of the core pin can be deviated easily, and the pin hole Even if the input is misaligned, it can be inserted without applying excessive force.

[0006]

【Example】

 An embodiment of the mold core pin of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an embodiment of a mold structure using a core pin of the present invention, and FIG. 2 is an enlarged view of a main part.

As shown in FIG. 1, a mold 1 employing the mold core pin of the present invention includes a fixed mold 2, a movable mold 3 and a sliding mold 4, and each of the molds 2, 3, 4 is The cavity 5 is formed in the mold clamped state.

Inside the cavity 5, there is a projection 6 projecting from the mating surface on either side of the fixed mold 2 or the movable mold 3. The projection 6 has a pin hole 6a. Has been drilled.

The sliding die 4 is slidable in the horizontal direction with respect to the fixed die 2. That is, the sliding die 4 includes a main body portion 10 connected to the cylinder unit 7 and a holding portion 11 integrally attached to the front surface of the main body portion 10, and the core pin 12 is attached to the holding portion 11. The main body 10 and the holding portion 11 are slidable on the slide receiving base 13.

Now, details of the connecting structure between the sliding die 4 and the core pin 12 will be described with reference to FIG.

The holding portion 11 is provided with a loose hole 11a extending along the sliding direction of the sliding die 4 and a large diameter hole 11b connected to the loose hole 11a.

Further, the core pin 12 is provided with a fitting portion 12a, an intermediate shaft portion 12b, and a base end portion 12c in this order from the tip end side to the base end side in the axial direction. The pin hole 6a can be inserted and the intermediate shaft portion 12b can be freely inserted into the floating hole 11a. Further, the base end portion 12c can be loosely fitted in the large diameter hole 11b.

The shaft diameter of the fitting portion 12a is set to be substantially the same as the inner diameter of the pin hole 6a so that the two fit closely to each other, while the shaft diameter of the intermediate shaft portion 12b is equal to that of the loose hole 11a. The diameter is made slightly smaller than the inner diameter, and the shaft diameter of the base end portion 12c is made smaller than the inner diameter of the large diameter hole 11b so that a gap is formed therebetween.

Further, the gap between the intermediate shaft portion 12b and the floating hole 11a is designed so that the tip end side is narrow and the base end portion side is wide through the step d of the floating hole 11a, and the gap is larger than these gaps. The gap between the end portion 12c and the large diameter hole 11b is made wider.

The rear end surface T of the base end portion 12c is formed into a spherical shape having a protruding shape and is brought into contact with the flat bottom surface H of the large diameter hole 11b.

Therefore, the core pin 12 is allowed to move within the range of the clearance between the floating hole 11a and the large diameter hole 11b, and by pressing the core pin 12 forward through the flat bottom surface H, the core pin 12 is moved forward. The axial direction of the pin 12 can be easily displaced.

Incidentally, the main body portion 10 of the sliding die 4 is provided with a concave portion 10 a, and the concave portion 10 a and a stopper protruding from the movable die 3 enable positioning.

In the die core pin as described above, after the fixed die 2 and the movable die 3 are clamped, the cylinder unit 7 is operated to move the sliding die 4 forward.

At this time, if the center of the core pin 12 and the center of the pin hole 6a are aligned with each other, the core pin 12 fits smoothly into the pin hole 6a, but even if the centers are misaligned, The end face T of the base end portion 12c of the child pin 12 swings lightly on the flat bottom surface H, and the axial direction of the core pin 12 can be changed and fitted in a state of following.

Therefore, the protrusion 6 is not applied with an excessive force, and not only the damage of the mold can be prevented but also the degree of fitting between the core pin 12 and the pin hole 6a can be increased.

Therefore, when molten metal such as aluminum is poured into the cavity 5 in such a state, there are no problems such as residual aluminum and reverse burr.

When the tunnel-shaped hole is formed by such casting, hole processing for increasing accuracy is performed as necessary.

[0023]

[Effect of device]

 As described above, in the mold core pin of the present invention, the base end face of the core pin that abuts the flat bottom surface of the large diameter hole of the holding part has a convex shape, and Since the intermediate shaft portion is movably inserted therein, the axial direction of the core pin can be easily converted, and the core pin can be fitted so as to follow even if it is displaced from the center of the pin hole. Therefore, no excessive force is applied to the mold, and it is possible to prevent problems such as reverse burr.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a mold structure adopting a core pin of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 Conventional diagram

[Explanation of symbols]

 1 Mold 5 Cavity 6a Pin Hole 11 Holding Part 11a Floating Hole 11b Large Diameter Hole 12 Core Pin 12a Fitting Part 12b Intermediate Shaft Part 12c Base End H Flat Bottom T Rear End Face

Claims (1)

[Scope of utility model registration request] 1. A mold core pin, which is held by a mold holding part and can be fitted into a pin hole facing a cavity, wherein the mold core pin is fit into the pin hole. A joint portion, an intermediate shaft portion that loosely inserts the loose hole of the holding portion, and a base end portion that loosely fits in the large-diameter hole of the holding portion, and the end face of the base end portion on the base end side has a convex shape. At the same time, the base end side end surface is brought into contact with the flat bottom surface of the large-diameter hole, and a mold core pin for a mold is provided.