JPH06182493A - Mold for casting blade - Google Patents

Abstract

PURPOSE:To provide a mold for casting blades which is low pattern manufacturing cost and can easily mold with high molding precision without needing the skillfulness. CONSTITUTION:A mold member for forming a space (cavity) Sb for blade matching to blade shape to be cast is constituted with dividable cores 20, 21 and an insert core 10 on the surface faced to the space Sb. At the time of molding, after inserting the insert core 10 around mold center axis X to constitute the lower mold, the cores 20, 21 are piled on the insert core 10 while following to the assembling order to the peripheral direction. A second blade forming surface 203 in each core 20, 21 is continued to the blade forming surface 105 in the insert core 10 to form the space Sb for blade in between these blade forming surfaces 203, 105 and a first blade forming surface 202 in the adjacent cores 20, 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for casting vane parts such as impellers for pumps.

[0002]

2. Description of the Related Art When molding a mold for casting impeller parts for pumps or the like, usually, a so-called pultrusion molding method in which a mold material such as sand is filled in a gap of a model having the same blade shape and the model is extracted. Is used. If the blade shape is three-dimensionally twisted and it is impossible to pull out the model after molding, use the vanishing model method like the lost wax method or deform the model by molding it with an elastic body such as rubber. The elastic model method of pulling out from the mold is generally used. However, the disappearance model method requires the same number of models as the number of castings, so that the model cost is high, and the elastic model method deteriorates the casting accuracy because the model is deformed by the weight of the mold material at the time of molding. Therefore, instead of each of the above-described molding methods, there is a case where an approach molding method is used in which a plurality of cores are combined to form a void according to the blade shape of the blade component to be cast.

16 and 17 show an example of a mold by the above-mentioned gathering type method. In this mold, a plurality of cores N are arranged side by side in the circumferential direction between a pair of lower mold L and upper mold U, and molten metal poured from a spout (not shown) is present between the cores N. As shown in FIG. 18, the impeller I including a plurality of (five in the figure) blades B spirally extending around the rotation axis is cast by wrapping around the blade void Sb. The core N has a main body M having a shape corresponding to the gap C between the blades of the impeller I to be cast, and baseboards Hi and Ho (hatched portions in FIG. 16) provided at both ends of the main body M. , The skirting boards Hi, Ho are fitted to the lower mold L or the upper mold U to hold each core N at a predetermined position. In such a grouping method, a large number of cores N can be molded from the same core taker, so that the cost of manufacturing a model is significantly reduced.

[0004]

However, in the above-mentioned approach-type method, since the blade B to be cast is three-dimensionally twisted around the rotation axis of the impeller I, as shown in FIG. When N is shifted in the circumferential direction and set in order, the first set core N1 protrudes above the gap C5 in which the last core N5 should be stored, and the last core N
It becomes impossible to lower 5 in the direction of the rotation axis and fit it in the lower mold L. In this case, it is conceivable to set the last core N5 while twisting it along the direction of twist of the blades, but the skirting board Hi on the center side does not get in the way.

Therefore, to set the above core N,
Combine all cores N so as to draw a circle larger than the actual assembly diameter (in this case, a large gap will be created between the cores N), and then each core N will be moved to the radial center side at the same time. It is necessary to gather them together, and considerable skill is required to carry out the work well. Moreover, in this gathering procedure, since it is difficult to balance the cores N with each other, the positioning accuracy of the cores N is poor, and the casting accuracy is likely to deteriorate. Even if there is no skirting board Hi, if the degree of twist of the blade B with respect to the rotation axis direction and the winding length around the rotation axis increase, the center side of the core N still interferes and the cores N are brought together. Will be difficult.

An object of the present invention is to provide a blade casting mold which is inexpensive in model production, can be easily molded without requiring skill, and has high casting precision.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 showing an embodiment, the present invention will be described with reference to a plurality of mold members 10, 2.
It is applied to the blade casting mold 1 which forms a space Sb corresponding to the blade shape of the blade component to be cast between these mold members 10, 20, 21 by combining 0 and 21. And the above-mentioned purpose has a plurality of mold members 10 and 2 forming the void Sb.
At least one mold member (10, 20) of 0, 21
Is achieved by dividing each of the mold members 10, 20, 21 in the middle of the surface 203 facing the space Sb so that the mold members can be combined sequentially from one side in the rotation axis direction of the blade component.

[0008]

If the part 10 forming the center side of the space Sb among the mold members (10, 20) divided in the middle of the surface 203 facing the space Sb is assembled first, the outer side of the space Sb is formed. The part 20 to be inserted can be inserted into the gap between the mold members 10, 20, 21 later without being disturbed by the part 10 on the center side.

Incidentally, in the section of means and action for solving the above-mentioned problems for explaining the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. It is not limited to.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The mold of this embodiment is for casting the above-mentioned five-blade impeller I shown in FIG. 18, and the configuration relating to the impeller I is to refer to FIG.

As shown in FIG. 1 and FIG. 2, in the mold 1 of this embodiment, five shifting molds 10 formed of a molding material such as foundry sand are arranged radially around the central axis X of the mold. , Molded from the same material as the grouping die 10 4
One core 20 and a single set core 21 are installed on the shifting mold 10 to form five blade voids Sb around the center axis X of the mold 1 according to the shape of the blade B of the impeller I. It Further, the upper mold 30 is put on the upper parts of the cores 20 and 21, and a cone corresponding to the boss portion (not shown in FIG. 18) of the impeller I is provided between the upper mold 30 and the shifting mold 10 and the cores 20 and 21. A shaped boss space Sc is formed.

As shown in FIGS. 1 to 4, the shift mold 10 includes a lower surface 100 orthogonal to the mold center axis X, a pair of side surfaces 101 parallel to the mold center axis X, and a cylindrical surface centered on the mold center axis X. And a substantially fan-shaped outer peripheral surface 102. The sandwiching angle of the side surface 101 is set to a value obtained by dividing 360 ° by the number of blades B (72 ° in the case of the embodiment). A stepped surface 103 and a boss forming surface 104 that form a boss space Sc, and a blade forming surface 105 that forms a blade space Sb are formed on the upper surface side of the gathering die 10. The blade forming surface 105 is curved in accordance with the center side of the reaction surface (concave surface side in FIG. 29) of the blade B to be cast, and on the outer peripheral side thereof, a tapered surface 106 having an upward slope toward the outer periphery of the shifting die 10. A core support surface 107 parallel to the lower surface 100 is continuously provided via the.

As shown in FIGS. 1, 2, and 5 to 7, the core 20 includes a core body 200 and skirting boards 210 and 220 arranged on the outer periphery of the core body 200. Core body 2
00 is on the outer peripheral side of the reaction surface of the blade B, and the curved surface 201 forming the boss space Sc, the first blade formation surface 202 which is curved to match the operation surface of the blade B (the convex surface side of FIG. 29). And a second blade forming surface 203 that is curved together.
The wall thickness between the blade forming surfaces 202 and 203 is thinner as the gap C of the blade B is narrower toward the center thereof, and is thinner from the outer periphery of the core body 200 toward the inner peripheral end face 204. Become.

The front end surface 204 of the core body 200 is a shift type 1
It can be brought into contact with the side surface 101 of 0 (see FIGS. 1 and 2). When these abut, the blade forming surface 1 of the pulling die 10
05 and the second blade forming surface 203 of the core 20 continuously form one curved surface corresponding to the reaction surface of the blade B.
Numeral 205 is a convex portion that fits with the concave portion 108 formed on the side surface 101 of the closing die 10 to position the inner peripheral side of the core 20, and 206 is a tapered surface. Also, the portion that protrudes downward contacts the tapered surface 106 of the shifting mold 10, and the remaining portion contacts the tapered surface 207 of the adjacent core 20 (see the right side of FIG. 2).

The skirting boards 210 and 220 are curved in an arc shape around the center axis X of the mold and are arranged in different steps in the direction of the center axis X of the mold.
Extending along the outer periphery of the curved surface 201 of the
Are provided so as to be shifted in the circumferential direction so as to extend along the outer circumference of the second blade forming surface 203. The center angles of the skirting boards 210 and 220 with respect to the center axis X of the mold are both set to a value obtained by dividing 360 ° by the number of blades B (72 ° in the case of the embodiment).

Upper surfaces 211 and 221 of the skirting boards 210 and 220
The lower surfaces 212 and 222 are formed on a plane orthogonal to the center axis X of the mold, and the lower surface 212 of the upper skirting board 210 and the upper surface 221 of the lower skirting board 220 are formed at the same height. Thereby, the lower surface 212 of the skirting board 210 of the one core 20,
When the upper surfaces 221 of the skirting boards 220 of the other cores 20 are brought into contact with each other, the upper surfaces 211 of the skirting boards 210 are flush with each other and the lower surfaces 222 of the skirting boards 220 are flush with each other. The outer peripheral surface 230 of the core 20 is formed into a cylindrical surface centered on the center axis X of the mold, and its radius of curvature is made equal to that of the outer peripheral surface 102 of the shifting mold 10.

The set core 21 is composed of a pair of split pieces 22 and 23 that can be split on split surfaces 22a and 23a provided on the extension of the mating surface of the gathering die 10, and the shape in the combined state is medium. It is exactly the same as the child 20. That is, the set core 21 is obtained by dividing the core 20 on the alternate long and two short dashes line Lc in FIGS. 5 and 6. Therefore, in the present specification, each component of the set core 21 is designated by the same reference numeral as that of the corresponding part of the core 20, and description thereof is omitted.

Next, the procedure for molding the mold 1 will be described with reference to FIGS. In order to mold the mold 1, first, as shown in FIG. 8 and FIG.
The lower mold is made by gathering around. Next, as shown in FIGS. 9 and 11, the divided pieces 22 of the core assembly 21 are positioned so that the second blade forming surface 203 thereof is continuous with the blade forming surface 105 of any one of the forming molds 10. 1
Place on top of 0. At this time, the skirting board 2 in the lower stage of the split piece 22
The lower surface 222 of 20 comes into contact with the core support surface 107 of the shifting die 10 to support the split piece 22 (see the left side of FIG. 2).

Next, as shown in FIGS. 10 and 11, the second blade forming surface 203 of the divided piece 22 and the skirting board 2 are formed.
The core 20 is lowered to the side of 20 and positioned so that the second blade forming surface 203 is continuous with the corresponding blade forming surface 105 of the closing die 10. At this time, the skirting board 2 of the divided piece 22
20 upper surface 221 and new core 20 upper skirting board 210
The lower surface 212 of the core contacts the core 20, and the core 20 is held. As a result, the first blade forming surface 202 of the core 20 and the divided piece 2
2nd blade formation surface 203 of 2 and gathering type 1 continuing to this
The blade forming surface 105 of 0 forms one blade space Sb.

Similarly, a new core 2 is provided on the side of the core 20.
0 is set, and the first blade forming surface 202 of each core 20 is set.
Then, the second blade forming surface 203 of the core 20 and the blade forming surface 105 of the pulling die 10 which are adjacent to each other sequentially form the blade space Sb. Fig. 1 with all four cores 20 set
After the state shown in 0 is reached, the second blade forming surface 203 and the skirting board 220 exposed in the gap C between the split piece 22 and the core 20.
The divided pieces 23 of the core assembly 21 are set so as to cover the upper surface 221 of the. After this, as shown by the two-dot chain line in FIG.
0 is covered with the upper mold 30, and the boss space Sc is formed between the surface of the upper mold 30 and the curved surface 201 of each core 20, 21 to the boss forming surface 104 of the shift mold 10 and the stepped surface 103.
To form. Then, a sprue and gas holes (not shown) are formed to complete the molding of the mold 1.

FIG. 12 shows a cross section of the mold 1 linearly developed on the blade space Sb. As you can see from this figure,
In this embodiment, the grouping mold 10 and the core 20, which are conventionally integrated,
Since 21 is separable, the cores 2 are arranged in order from the divided pieces 22 of the set core 21 after the molds 10 are brought together.
By setting 0 and 21, and finally setting the divided piece 23, the gathering mold 10 and the cores 20 and 21 can all be combined from one side of the mold central axis X, and the core 20 can be twisted or plural. There is no need to bring the inner cores 20 together. Therefore, the mold 1 can be easily molded without requiring skill, and the positioning accuracy of the shifting mold 10 and the cores 20 and 21 can be improved to improve the casting accuracy. Type 1
Once the models of 0 and cores 20 and 21 are prepared, it is not necessary to manufacture the models thereafter, so that the model cost is low as in the conventional grouping method. Since the cores 20 and 21 and the shifting mold 10 are separate bodies, the weight is reduced, deformation and displacement due to their own weight are prevented, and casting precision is further enhanced.

In this embodiment, especially the skirting board 2 of the cores 20 and 21
Positioning of the cores 20 and 21 is made possible by providing 10 and 220 in two stages in the direction of the mold center axis X and overlapping the skirting boards 210 and 220 of the adjacent cores 20 and 21 in the direction of the mold center axis X. Accuracy and stability are further enhanced. Baseboard 210,2
When only one of the 20 is selected, the central angle of the skirting board is determined by the number of blades B, that is, the number of circumferentially divided cores 20 and 21, so that the circumferential length of the skirting board is the blade forming surface. Compared with the circumferential length of 202, 203, it is insufficient and the core 2
There is a risk that the stability of 0, 21 will be impaired and the casting accuracy will deteriorate. Further, since the lower mold is constituted by the gathering mold 10, the number of parts constituting the mold 1 is reduced and the molding cost is reduced.

In this embodiment, all the cores 20,
Although 21 is provided so as to be separable from the grouping mold 10, FIG.
As shown in Fig. 1, one core 20 and the centering die 10 can be divided, and the remaining cores are cores 20A and 21A integrated with the centering die, but all the cores are on one side of the mold central axis X. Can be combined in order. As shown in FIG. 14, even if the set core is changed to the core 20B that can be divided only with the grouping die 10, if the core 20B is slid along the blade gap Sb, the last core 20B is also set. Since it is possible, molding is easier than the conventional method in which all cores are set at the same time. In the example of FIG. 14, both ends 24 of the skirting board 240 are provided so as not to obstruct the sliding of the core 20B in the direction of the blade gap Sb.
It is necessary to incline 1 and 242 along the blade gap Sb. Although the lower mold 40 is combined with the lower mold 40 in the embodiment, a lower mold 40 may be separately provided as shown in FIG. The lower mold may be formed by integrally forming the grouping mold 10 without dividing it.

In the above embodiment, the combination of the one core 20 or 21 and the one gathering die 10 constitutes one die member. The mold center axis X corresponds to the rotation axis of the blade member.

[0025]

As described above, according to the present invention,
Mold members that form voids corresponding to the shape of the blade to be cast can be combined in order from one side in the direction of the rotation axis of the blade component, so molding can be easily performed without skill, and casting accuracy can be improved. . The advantage of the group-type method that the model production cost is low is not damaged at all.

[Brief description of drawings]

FIG. 1 is a plan view of a mold according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a plan view of a grouping type according to the embodiment.

FIG. 4 is a side view from the IV direction in FIG.

FIG. 5 is a plan view of the core of the embodiment.

FIG. 6 is a side view from the VI direction in FIG.

7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is a plan view of a case where the molds are brought together in the embodiment.

FIG. 9 is a plan view showing a state in which the first core is set in the embodiment.

FIG. 10 is a plan view showing a state before the last core is set on the closing mold in the embodiment.

FIG. 11 is a perspective view showing a procedure for assembling the core of the embodiment.

FIG. 12 is a cross-sectional view of the mold of FIG. 1 linearly developed on a blade gap.

FIG. 13 is a diagram showing a modified example in which the split state of the core is changed.

FIG. 14 is a diagram showing another modification in which the split state of the core is changed.

FIG. 15 is a view showing a modified example in which a lower die is provided separately from the shifting die.

FIG. 16 is a cross-sectional view showing a conventional mold structure.

FIG. 17 is a cross-sectional view of the conventional mold developed on the alternate long and short dash line Y in FIG.

FIG. 18 is a plan view showing an example of a blade to be cast.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 mold 10 closing type 20,21 core 105 closing type blade forming surface 202 1st blade forming surface of core 203 2nd blade forming surface of core B impeller blade I impeller Sb blade gap X mold center axis

Claims (1)

[Claims] 1. A blade casting mold that combines a plurality of mold members to form a gap between the mold members according to the shape of a blade component to be cast, wherein among the plurality of mold members that form the gap. A blade casting mold characterized in that at least one mold member is divided in the middle of a surface facing the gap so that each mold member can be sequentially combined from one side in the rotation axis direction of the blade component.