JP3558993B2 - Die casting mold - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention, in the work molding by die casting, to make the molding accuracy on both sides of the fixed mold side and the movable mold side extremely high, to achieve high dimensional accuracy over the front and back sides of the work only by die casting, and work The present invention relates to a die-casting die capable of improving efficiency and thus reducing manufacturing costs.
[0002]
[Prior art]
In die casting, when a work is formed from a fixed die and a movable die that constitute a die, dimensional accuracy may be involved in both the fixed die and the movable die. Specifically, an axis between a hole forming position on one side surface (for example, the front surface) of the work and another hole formed on the corresponding other side surface (for example, the back surface) with reference to the center of the hole forming position. This is the case where extremely high dimensional accuracy is required for the distance.
[0003]
As such a work, there is a casing or the like for housing a speed change mechanism of a motorcycle or the like that requires a bearing. In such a case, generally, based on the dimensional accuracy of the molded part formed on one side of the work, a molded part such as a hole on the other side is formed, and a high dimension is formed over the front side and the back side. If the accuracy was satisfied, cutting was required after die casting.
[0004]
[Problems to be solved by the invention]
If high dimensional accuracy is required at two or more locations on the same side of the work (front only if front, back only if back), the molding surface of the fixed or movable die-casting die Can be formed only on one mold surface, so that the dimensional accuracy can be easily improved, and high dimensional accuracy can be satisfied by casting using a die casting die.
[0005]
However, when the same dimensional accuracy is straddling the front and back surfaces of the work, the corresponding mold is divided into a fixed die and a movable die which constitute the corresponding mold, and in the separated state, the front and rear surfaces are separated. It has been extremely difficult to increase the dimensional accuracy of the distance between the main molded object as the dimension reference and the molded object whose dimensions are set based on the main molded object.
[0006]
The reason is that the fixed mold is firmly fixed to the mold apparatus, while the other movable mold is operationally guided by a movable guide rod (generally referred to as a "guide pin") of the apparatus. In order to improve the operability of the movable mold, the gap between the sliding part of the movable mold and the guide pin should be almost zero, but it is impossible in practice because the operation of the movable mold deteriorates. . Therefore, there is a means of minimizing the gap to increase the dimensional accuracy of the fixed type with the fixed type. However, even in this case, as in the case of the above-described work, the dimensional accuracy of the axial distance between the front surface and the back surface is high. It is difficult to do.
[0007]
As a result, a high-precision mold can be completed, and the accuracy of the mold at room temperature can be fixed and the accuracy of the movable mold can be kept high. When a temperature difference occurs, the engagement accuracy and operation of the guide pin and the guide bush, which maintain the alignment accuracy of the mold, are increased due to the rise in temperature.
[0008]
In addition, in order to secure the dimensional accuracy of the desired center distance by performing cutting or the like, the processing cost increases, or processing equipment other than casting is required, so that the manufacturing cost of the equipment increases. Therefore, it was difficult to reduce the cost. The work cannot be formed with high dimensional accuracy over both surfaces of the work by only die casting, which can form the work rationally, and the combination with the cutting is indispensable. SUMMARY OF THE INVENTION An object of the present invention is to increase the dimensional accuracy over the front side and the back side of a work by only die casting without cutting, improve work efficiency, and thereby reduce manufacturing costs.
[0009]
[Means for Solving the Problems]
Therefore, the inventor of the present invention has conducted intensive studies to solve the above-mentioned problems. As a result, the present invention shows that the present invention has a front-side main molded portion formed on the front side and a rear-side main molded portion formed on the back side. The back side main molding section is a mold for molding a work whose position is set by the same reference center, and is movable in a small range to a fixed mold, a movable mold, and the fixed mold. A first core having a surface, a second core mounted on the movable mold and having a mold surface of the back side main molding portion, and tapered holes formed in the first and second cores, respectively. And a tapered projecting portion inserted and connected to the tapered hole portion. When the tapered hole portion and the tapered projecting portion are properly joined, their respective axes are aligned in a straight line. The axis of the hole or tapered projection should not match the reference center. By was die-casting die, the dimensional accuracy over the front and back sides of the workpiece only by die casting to high, to improve the work efficiency can be suppressed and thus manufacturing cost, is to solve the above problems.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the work W formed by the die casting mold of the present invention will be described. A front side 10 or a back side 11 is set on the work W, respectively. The front side 10 and the back side 11 are names set for convenience, but specifically, when the workpiece W is a component constituting a casing, the outside side is the front side 10 and the inside side is the back side 11. [See FIGS. 4A, 4B, and 4C].
[0011]
The workpiece W, there is a main mold section area W _1. The main molded portion area W1 is determined based on the molded portion on _one of the front side 10 and the rear side 11 and the distance from the molded portion to the other molded portion is determined on the other side. This is a region where the dimensional accuracy between the corresponding molded parts must be set extremely high, especially on the front side 10 and the back side 11.
[0012]
First, on the front side 10, front-side main molding portion 13 is formed, the backside main molding portion 14 is formed on the back side 11, the front-side main molding portion 13 and the back-side main forming section 14, a common reference cardiac P ₀ Based on. That is, the main molding region W ₁ includes a front-side main forming section 13 and the back-side main forming section 14 over the front side 10 and back side 11 of the workpiece W, the area must be as accurate dimensions. The main molding unit does not belong to the region W ₁ front forming portion 15 and back mold portion 16 is also present, these are obtained by eliminating the need for high molding precision, has a relatively large allowable dimension.
[0013]
Said reference cardiac P ₀ is the center point of the reference hole 12 formed in an arbitrary position of the workpiece W [FIG 4 (A), (B) , (C) refer to Fig. The reference hole 12, a radius L _0, is a part that is molded first core A to be described later, or by the second core B. The front-side main forming section 13 is formed with a distance determined by the high dimensional accuracy from the reference cardiac P _0. The front side main forming part 13 may be one or plural. In the embodiment shown in FIG. 4 (A) and the like, three front side main molded portions 13 are formed. The back side main molded portion 14 is a storage portion such as a bearing in the illustrated one.
[0014]
Then, a typical dimension of the reference cardiac P ₀ to the front-side main molding 13 and L _1, a typical dimension of the reference cardiac P ₀ to the backside main molding 14 and L _2. The front side main molded portion 13 is formed as a hole, but there are also cases where the front side main molded portion 13 is a projection, and the projection and the hole are sometimes integrated. The front-side main forming section 13, which is shown are formed from the hole portion 13a and the protrusion 13b, the distance between the reference center P ₀ and the hole 13a becomes the L ₁ [FIG. 4 (A) , FIG. 5 (C) etc.].
[0015]
The back side main molded portion 14 is a portion for accommodating a bearing or the like, in which a circumferential wall portion 14a is formed, the center of the inner diameter is the reference center P ₀ , and the radius is L ₂ . [See FIGS. 4B and 5C]. The work W is, for example, a casing of a transmission of a two-wheeled vehicle, and a storage part for mounting a bearing is formed as a circumferential wall around a reference hole 12 formed on a back side 11.
[0016]
Next, the die casting mold will be described. The die casting mold includes a fixed mold 1 and a movable mold 2 (see FIGS. 1A and 1B). The fixed mold 1 is fixed to a mold apparatus and is always immobile even during operation. The movable mold 2 moves toward the fixed mold 1 and comes into contact with or moves away from the fixed mold 1. The fixed mold 1 and the movable mold 2 have mold surfaces 1a and 2a, respectively, for molding the work W into various shapes.
[0017]
A first core A is mounted on the fixed die 1. Further, the second core B is mounted to the movable die 2, these first cores A and the second core B, the main molding area W ₁ of the workpiece W is formed. The first core A and the second core B are formed with a tapered joint 3 respectively. The first core A and the second core B are connected to each other by the tapered joint 3. (Pa, Pb) coincide with each other on a straight line.
[0018]
The first core A and the second core B is around each of the tapered joint portion 3, a main molding to the front-side main forming section 13 which is formed in the main molding area W ₁ of the workpiece W is formed Mold surfaces 4 are formed respectively. The tapered joint 3 has a tapered protrusion 3b and a tapered hole 3a. A tapered hole 3a is formed in one of the first core A and the second core B, and a tapered protrusion 3b is formed in the other. The first core A and the second core B have a structure in which the tapered protrusion 3b is inserted into and joined to the tapered hole 3a [FIGS. 7A, 7B, and 7C]. reference〕.
[0019]
The tapered joint 3 is a part for forming the reference hole 12 of the work W, and the respective axes Pa and Pb of the tapered joint 3 when the tapered hole 3a and the tapered protrusion 3b are properly joined. is coincident with the straight line, [see FIGS. 6 and 7 (C)] these axis are consistent with the reference center P ₀ of the reference holes 12. In the illustrated embodiment, the tapered protrusion 3b is provided on the second core B, and the tapered hole 3a is provided on the first core A. The core A may be provided with a tapered protrusion 3b, and the second core B may be provided with a tapered hole 3a (see FIG. 3B).
[0020]
The second core B is fixed in an immovable state with respect to the movable mold 2. That is, the second core B is formed substantially integrally with the movable mold 2 and does not move with each other. In the fixed die 1 and the first core A, the first core A is movable in a small range with respect to the fixed die 1. Specifically, a core mounting chamber 1b is provided at a mounting location of the first core A in the fixed die 1, and the first core A is disposed in the core mounting chamber 1b so as to be movable within a small range. Have been.
[0021]
As shown in FIG. 3, the first core A is formed in a substantially cylindrical shape, and one end of the cylindrical portion 5 in the axial direction is the main mold surface 4, and a flange 6 is formed at the other end. I have. The flange 6 serves to prevent the first core A mounted in the core mounting chamber 1b from coming off the core mounting chamber 1b in the axial direction.
[0022]
The inner diameter H of the core mounting chamber 1b is slightly larger than the outer diameter D of the column 5 and has a relationship of H> D (see FIG. 2). Therefore, a gap S is formed between the inner periphery of the core mounting chamber 1b and the cylindrical portion 5 of the first core A, and the first core A is slightly smaller than the fixed mold 1 due to the gap S. It can be moved. The second core B is formed in the shape of a thick shaft, and the tapered joint 3 is formed at the shaft end of the shaft 7, and the main mold surface 8 is formed around the tapered joint 3. Is formed.
[0023]
Since the first core A is movable within a small range with respect to the fixed die 1, the movable die 2 comes into contact with the fixed die 1, and the taper between the first core A and the second core B is made. When the joining portion 3 is joined, the first core A slightly moves, the axes of the tapered joining portion 3, the tapered projecting portion 3b, and the tapered hole portion 3a coincide, and the first core A and the second core A and a core B properly face, the molding of the main molding region W ₁ can be accurately performed.
[0024]
[Action]
First, the movable mold 2 is moved closer to the fixed mold 1 and the first core A and the second core B are also approached, and the tapered protrusion 3b is inserted into the tapered hole 3a [FIG. 7 (A)]. At this time, the axis Pa of the first core A is shifted by d from the axis Pb of the second core B due to the gap S, but as the tapered protrusion 3b is inserted deeper into the tapered hole 3a. Gradually, the axis Pa of the tapered hole 3a and the axis Pb of the tapered protrusion 3b approach a direction in which the axis Pb becomes linear, and the axis Pa moves in a direction coincident with the axis Pb. The protrusion 3b is properly joined (see FIG. 7B).
[0025]
Here, the axis Pb of the tapered protruding portion 3b, assuming that matches the reference cardiac P _0, at a proper connection is established between the tapered protrusion 3b and the tapered hole portion 3a, the axial center Pa of the tapered hole portion 3a not match the reference cardiac P _0, the tapered joint portion 3 in a state in which the tapered hole portion 3a and the tapered protruding portion 3b is connected, becomes coincident with the reference center P ₀ [FIG. 7 (C) reference〕.
[0026]
That is, the reference hole 12 is formed on the front side 10 or the back side 11 of the work W by the connection of the tapered holes 3a and the tapered protrusions 3b of the first core A and the second core B, and the tapered joint 3 is formed. can be carried out in connection axis is the reference center P _0, and the molding of the main molding region W ₁ with high accuracy. Thus, each of the main forming mold surface 4 of the first core A and the second core B on the basis of the reference cardiac P ₀ of molding the front-side main forming section 13 and the backside main forming section 14, each of which common The dimensions are set (see FIG. 7).
[0027]
【The invention's effect】
According to the first aspect of the present invention, the front side main forming portion 13 is formed on the front side 10 and the back side main forming portion 14 is formed on the back side 11, and the front main forming portion 13 and the back side main forming portion 14 have the same reference center P _0. A fixed mold 1, a movable mold 2, and a first mold having a mold surface of the front side main forming portion 13 which are movable in a small range to the fixed mold 1, A core A, a second core B attached to the movable mold 2 and having a mold surface of the back side main molding portion 14, and tapers formed on the first core A and the second core B, respectively. It comprises a hole 3a and a tapered projection 3b inserted and connected to the tapered hole 3a. When the tapered hole 3a and the tapered projection 3b are properly joined, their respective axes are aligned on a straight line. And the axis of the tapered hole 3a or the tapered projection 3b By having a die-casting die made coincident with the reference center P ₀ is the dimensional accuracy over the front and back sides of the workpiece only by die casting to high, to improve the work efficiency, it is suppressed and thus the manufacturing cost It has the effect of being able to do so.
[0028]
More specifically, the first core A is mounted on the fixed die 1, and the first core A is movable in a small range with respect to the fixed die 1. Further, the second core B is mounted on the movable die 2 and the movable die 2 is brought into contact with the fixed die 1 by the tapered hole 3a and the tapered protrusion 3b, so that the first core A is The second core B is also joined by the tapered hole 3a and the tapered protrusion 3b. At this time, by fixing the tapered projecting portion 3b in an immobile state other than in the axial direction, the axis Pb of the tapered projecting portion 3b is determined, and the tapered hole portion 3a to be taper-joined by the tapered projecting portion 3b is determined. The axis Pa coincides with the axis Pb, and becomes the axis in the taper joining state.
[0029]
Shaft center, since coincides with the reference cardiac P _0, molded part due to the first core A and the second core B, the reference center P ₀ the front-side main molding portion 13 and the backside main forming unit 14 as a reference The molding position can be extremely accurate. In the present invention, these steps can be performed only by die casting, and the structure can be simplified. Furthermore, high-precision processing is enabled only by casting processing, so that processing costs can be reduced. Further, since there is no need for processing equipment such as cutting processing, it is possible to provide products without increasing manufacturing costs. Can be.
[0030]
Next, according to a second aspect of the present invention, in the first aspect, the tapered joint portion 3 is a tapered hole portion 3a in the first core A and a tapered projecting portion 3b in the second core B. The connection between the first core A and the second core B can be made almost accurately.
[Brief description of the drawings]
1A is a cross-sectional view showing a state in which a fixed mold and a movable mold are separated from each other in the present invention; FIG. 1B is a cross-sectional view showing a casting operation state in which the fixed mold and the movable mold are in contact with each other in the present invention; FIG. 2 is an enlarged cross-sectional view of a main part in a state where a fixed mold and a movable mold are separated. FIG. 3A is a perspective view of a first core, and FIG. 3B is a perspective view of a first core. FIG. 4A is a plan view of the front side of the work, FIG. 4B is a plan view of a main part of the back side of the work, and FIG. 4C is a plan view of the main part of the work. FIG. 5 (A) is a front perspective view of the main molded portion area, FIG. 5 (B) is a perspective view of the back side of the main molded portion region, and FIG. 5 (C) is a longitudinal sectional side view of the main molded portion region. FIG. 7A is an enlarged cross-sectional view showing a state in which a tapered protrusion is inserted into a tapered hole and their respective axes are aligned. FIG. (B) is a cross-sectional view showing a state in which insertion of the tapered protrusion into the tapered hole is started and the respective axes are moving in the same direction. Sectional view of the state where the center and the reference center coincide and the work is formed
A: first core B ... second core 1 ... fixed die 2 ... movable die 3 ... tapered joint 3a ... tapered hole 3b ... tapered protrusion 10 ... front side 11 ... back side 13 ... front side main molded part 14 ... back side Main molded part P ₀ … Reference center W ₁ … Main molded part area

Claims (2)

A front mold part is formed on the front side, and a back main mold part is formed on the back side, and the front main mold part and the back main mold part are fixed molds for molding a work whose position is set by the same reference center. A movable core, a first core having a mold surface of the front side main molding portion, which is movable in a small range to the fixed mold, and a mold surface of the back side main molding portion attached to the movable mold. A second core, a tapered hole formed in each of the first core and the second core, and a tapered protrusion inserted into and connected to the tapered hole. The die casting is characterized in that the respective axes are aligned in a straight line in a state where the parts are properly joined, and the axis of the tapered hole or the tapered projection is aligned with the reference center. Type. The die casting die according to claim 1, wherein a tapered hole is formed in the first core, and a tapered protrusion is formed in the second core.

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