JP5700457B2 - Lot mark assignment structure - Google Patents

Description

  The present invention relates to a lot mark imparting structure used in a mold for forming a lot mark on a cast product such as a die-cast part.

Die cast products are marked with lot marks for quality control. As a lot mark, the year, month, day, etc. of manufacture is usually formed by stamping or embossing on a predetermined part of the wall surface of the product.
Conventionally, for example, a lot mark pin as shown in FIG. 6A is used as a lot mark providing structure for forming such a lot mark.
In other words, the lot mark pin 50 includes a disk-shaped head 51 whose surface is engraved with the date of manufacture, and a screw portion 53 extending perpendicularly to the plate surface from the center of the back surface. Then, a screw hole 8 is formed in the wall surface 4 facing the upper mold 2 of, for example, the lower mold 3 ′ of the die casting mold, and the screw portion 53 of the lot mark pin 50 described above until the back surface of the head 51 contacts the wall surface 4. Screw in and fix.
A straight groove 52 is formed on the surface of the head 51 for engaging a minus driver when the screw portion 53 is screwed into the screw hole 8.

6 (b) in FIG. 6 (b) by the lot mark pin 50 on the wall portion of the die cast product 40 'in which a molten aluminum or magnesium is poured between the upper die 2 and the lower die 3' to form a predetermined wall portion. As shown in FIG. 6, a circular recess 55 corresponding to the head 51 is formed, and the date Md with the inscription reversed is displayed as a raised character on the bottom surface of the recess. Reference numeral 57 in the drawing is a linear protrusion formed corresponding to the linear groove 52 of the head 51.
A similar lot mark imparting structure is also disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-74234.

JP 2004-74234 A

However, in the above conventional example, if only one month mark / day of manufacture is applied with one lot mark pin, each lot mark pin can be used only once each year, and 365 types can be used for one year. Lot mark pins must be set.
Therefore, using two lot mark pins stamped with month numbers and lot mark pins stamped with day numbers, the month numbers were stamped if they were displayed at two locations adjacent to each other on the wall of the die cast product. Lot mark pins can be used repeatedly during the same month, and lot mark pins stamped with day numbers can be used repeatedly on the corresponding day of each month, so the number of set lot mark pins can be relatively reduced.

However, even in this case, a total of 43 types of 12 lot mark pins engraved with the month number and 31 lot mark pins engraved with the day number are required, and a part to be prepared to give the lot mark. It must be said that the score is still large and the management is troublesome.
Accordingly, an object of the present invention is to provide a lot mark applying structure in which the number of parts to be prepared is further reduced.

  For this reason, the lot mark imparting structure of the present invention is such that the first mark plate and the second mark plate, which are overlapped with each other, are fixed to the mold with a stop screw penetrating each center hole. The second mark board has a character shape for displaying a plurality of days at a predetermined interval in the circumferential direction of the surface at a radial position corresponding to the window hole. It is assumed that a character shape is displayed on the back of the 1-mark board and displaying a date selected from the plurality of days in the window hole.

  According to the present invention, if the first mark board is set to 12 types corresponding to each month from January to December, and the second mark board is set within the year by setting the number of groups divided from 1st to 31st into a plurality of groups. It can respond to all day. Therefore, the total of the first mark board and the second mark board is a small number of (12 + number of groups), and the number of parts and the management man-hour are reduced.

It is a fragmentary sectional view which shows the structure of embodiment. It is sectional drawing of a lower mold | type. It is a figure which shows a 1st mark board and a 2nd mark board. It is a figure which shows a stop screw. It is a figure which shows the lot mark display part of die-cast product. It is a figure which shows a prior art example.

Hereinafter, embodiments in which the present invention is applied to an aluminum or magnesium die casting die will be described in detail.
FIG. 1 is a partial cross-sectional view showing the configuration of the embodiment.
The mold 1 is composed of an upper mold 2 and a lower mold 3 that form a space in which molten aluminum or magnesium is poured facing each other.
In this embodiment, in order to display the month and day of manufacture, the first mark board 10 and the second mark board 20 each having a circular outer shape are stacked on top and bottom, and the lower mold 3 of the mold 1 is secured by a set screw 30. Use fixed.
The first mark board 10 and the second mark board 20 are both 2 to 3 mm thick and are made of hot tool steel similar to the mold 1, and the set screw 30 is preferably hot tool steel.

FIG. 2 is a cross-sectional view of the lower mold 3.
The lower mold 3 is formed with a recess 5 that accommodates the first mark board 10 and the second mark board 20 that are stacked on the wall 4 facing the upper mold 2, and is stopped at the center of the bottom surface 7 of the recess 5. A screw hole 8 into which the screw 30 is screwed is opened.
The inner wall 6 of the recess 5 has a conical surface with an opening edge having an enlarged diameter on the opening side, and a cylindrical surface on the bottom surface 7 side.

3A and 3B show the first mark board 10 and the second mark board 20, wherein FIG. 3A is a plan view of the first mark board 10, FIG. 3B is a cross-sectional view taken along the line AA in FIG. A plan view of the two-mark board 20, (d) is a BB section sectional view in (c).
First, as shown in (b), the first mark board 10 has a center hole 11 through which the retaining screw 30 passes, and one window hole 14 outside the center hole 11.
The center hole 11 has a conical surface (a dish shape) in which the inner wall 12 expands upward, with the opening on the back surface 10b of the first mark board 10 being the minimum diameter. The minimum diameter of the center hole 11 is larger than the screw diameter of the set screw 30 by a predetermined amount.
The inner wall 15 of the window hole 14 is given a draft as a conical surface whose diameter is increased upward. The draft is preferably about 5 °. The same applies to drafts of other portions described later.
The outer diameter of the front surface 10 a of the first mark board 10 is larger than the outer diameter of the back surface 10 b, and the outer peripheral surface 17 forms a conical surface that matches the inner wall 6 of the opening of the recess 5 in the lower mold 3.

As shown in FIG. 3A, the month number 18 is imprinted on the surface 10a of the first mark board 10 with left-right reversed characters. The marking position of the month number 18 may be arbitrary, but the vicinity of the window hole 14 is most preferable.
On the back surface 10b of the first mark board 10, as shown by broken lines, eight concave grooves 19 are formed from the hole edge of the center hole 11 radially to the vicinity of the outer peripheral edge at equal angular intervals, and the window hole 14 is adjacent. It is located in the center in the circumferential direction between the two concave grooves 19.
As for the 1st mark board 10, 12 types whose month numbers 18 are "1"-"12" are prepared as a basic set.

Next, as shown in FIG. 3 (d), the second mark board 20 stacked under the first mark board 10 has a center hole 21 through which the set screw 30 passes, and the center hole 21 is the first hole. The diameter is constant according to the minimum diameter of the center hole 11 of the mark board 10 (opening diameter in the back surface 10b).
The outer peripheral surface 22 of the second mark board 20 forms a cylindrical surface that is aligned with the bottom surface 7 side of the inner wall 6 of the recess 5 in the lower mold 3.
The depth H (see FIG. 2) from the wall surface 4 of the lower mold 3 to the bottom surface 7 of the recess 5 is set to be equal to the total thickness of the first mark board 10 and the second mark board 20.

As shown in FIG. 3C, on the surface 20a of the second mark board 20, eight beads 23 received in the concave grooves 19 of the first mark board 10 are formed in the holes of the center hole 21 at equal angular intervals. It is formed radially from the edge to the vicinity of the outer peripheral edge. And the day number 25 is stamped by the serial number in the circumferential direction center between the adjacent beads 23 and 23 sequentially. That is, in the case shown in FIG. 3C, the day numbers 25 of “1” to “8” are sequentially engraved in the clockwise direction between the beads 23 with the left and right reversed characters. However, the cross section of the marking is omitted in FIG.
Although not shown in particular, between the beads 23, those in which the day numbers 25 of “9” to “16”, “17” to “24”, “25” to “31” are similarly engraved are set. A total of four types of 2-mark board 20 are prepared as a basic set.

The direction of the date number 25 is set so that the outer side in the radial direction is upward along the radial line from the center of the second mark board 20.
Note that the direction of the letter of the month number 18 stamped on the first mark board 10 is the same as the diameter line L of the first mark board 10 passing through the center of the window hole 14, as shown in FIG. It is preferable to set them so that the window hole 14 side is parallel to the center hole 11 and the direction of the day number 15 is the same.
The total number of the first mark board 10 and the second mark board 20 is 16 in the basic set, but preliminary production is optional.

4A and 4B show the set screw 30, wherein FIG. 4A is a top view and FIG. 4B is a partially broken side view.
The stop screw 30 is a so-called countersunk screw, and as shown in FIG. 5B, the outer peripheral surface 33 of the head 31 forms a conical surface that aligns with the inner wall 12 of the center hole 11 of the first mark board 10, and In the embodiment, a thick shaft portion 34 corresponding to the center hole 21 of the second mark board 20 is further provided following the head 31, and a screw portion 35 is slightly thinner below the thick shaft portion 34.
The length S from the upper surface 32 of the head 31 of the set screw 30 to the lower end of the thick shaft portion 34 is set to be slightly smaller than or equal to the total thickness of the first mark board 10 and the second mark board 20. It is. When the outer peripheral surface 33 of the head 31 is seated on the inner wall 12 of the center hole 11 of the first mark board 10, the upper surface 32 of the head 31 is flush with the surface 10 a of the first mark board 10.
As shown also in (a), a hexagonal hole 36 for wrench engagement is provided in the center of the upper surface 32 of the head 31. The inner wall 37 of the hexagonal hole 36 is slightly inclined so as to give a draft and expand upward.

  In preparing the mold 1, the first mark board 10 engraved with the month number 18 corresponding to the manufacturing date and the second mark board 20 imprinted with the day number 25 are respectively selected from a plurality of days. The first mark board 10 and the second mark board 20 are aligned in the rotation direction (circumferential direction) so that 25 faces the window hole 14. Thereby, each bead 23 fits into the concave groove 19, and the former back surface 10b and the latter surface 20a are in contact with each other with the first mark board 10 and the second mark board 20 positioned with respect to each other.

  As shown in FIG. 1, the first mark board 10 and the second mark board 20 are fitted into the recess 5 of the lower mold 3 so that the back surface 20b of the second mark board 20 is seated on the bottom surface 7, and both marks When the set screw 30 is screwed into the screw hole 8 through the center holes 11 and 21 of the boards 10 and 20, the first mark board 10 and the second mark board 20 are fixed to the lower mold 3. The upper surface 32 of the head 31 of the set screw 30 is flush with the surface 10a of the first mark board 10, and the surface 10a of the first mark board 10 except for the hexagonal hole 36 (see FIG. 4) and the window hole 14 is Including the head 31, the flat surface is flush with the wall surface 4 of the lower mold 3.

Since the outer peripheral surface 17 of the first mark board 10 forms a conical surface aligned with the inner wall 6 of the opening of the recess 5, the outer peripheral surface 17 of the first mark board 10 and the inner wall 6 of the opening of the recess 5 are in close contact. .
The month number 18 stamped on the surface 10a of the first mark board 10 is present, and the same stamped day number 25 appears in the window hole 14.
As a result, as shown in FIG. 5, the month of manufacture Mm is displayed on the wall of the die-cast product 40 manufactured by filling the upper mold 2 and the lower mold 3 with molten aluminum or magnesium. In the vicinity thereof, an island 43 corresponding to the window hole 14 protrudes, and a lot mark display portion 42 with the production date Md displayed on the upper surface of the island 43 appears. Confirmation is easy. Incidentally, reference numeral 44 in the figure denotes a protrusion formed corresponding to the hexagonal hole 36 of the set screw 30.

Since the outer peripheral surface 33 of the head 31 of the set screw 30 and the inner wall 12 of the center hole 11 of the first mark board 10 are in close contact with each other, the occurrence of burrs caused by the molten metal flowing between them is prevented.
Similarly, since the outer peripheral surface 17 of the first mark board 10 and the inner wall 6 of the recess 5 are in close contact with each other, the generation of burrs between them is also prevented. If the outer peripheral edge on the surface 10a side of the first mark board 10 is chamfered, a circular bead 45 corresponding to the chamfered portion as shown by an imaginary line in FIG. 5 is formed, and the embossed characters of the month Mm and the day Md are formed. The lot mark display unit 42 can be easily recognized.

  In the present embodiment, the month number 18 corresponds to the first mark shape in the invention, and the day number 25 corresponds to the second mark shape.

The embodiment is configured as described above, and in order to form a lot mark at a predetermined portion of the die-cast product 40, the first mark board 10 and the second mark board 20 which are overlapped with each other pass through the center holes 11 and 21, respectively. The first mark board 10 has a month number 18 stamped on its surface 10a and has a window hole 14, and the second mark board 20 is fixed to a mold (lower mold 3) with a retaining screw 30. A plurality of day numbers 25 are imprinted at predetermined intervals in the circumferential direction of the front surface 20a at the radial positions corresponding to the window holes 14 and overlapped on the back surface 10b of the first mark board 10, and the day number 25 selected from among the plurality of day numbers 25 is provided. The first mark board 10 is divided into 12 groups corresponding to each month from January to December, and the second mark board 20 is divided into a plurality of groups from 1st to 31st. The number of groups By setting, it can accommodate full-time of the year. For example, if the second mark board 20 is divided into groups of 8 days, only four kinds are required, so the total number of the first mark board 20 and the first mark board 10 is 16 kinds (sheets), and the number of parts and the management man-hours are reduced.
Also, since the first mark board 10 and the second mark board 20 are overlapped and fixed at one place with the fixing screw 30, the lot mark pin with the month number and the lot mark pin with the day number are fixed at two places. Compared with, the layout is good and the position setting of the lot mark display part is easy.
(Effects corresponding to claims 1 and 8)

  Further, since the day number 25 is engraved on the front surface 20a of the second mark board 20 as described above, when the first mark board 10 and the second mark board 20 are overlapped, the front surface 20a and the back surface of the first mark board 10 are overlapped. 10b can be closely related. Therefore, the occurrence of burrs caused by the molten metal flowing into the window hole 14 entering the gap between the first mark board 10 and the second mark board 20 is prevented. (Effects corresponding to claim 2)

  A concave groove 19 is provided on the back surface 10 b of the first mark board 10 facing the second mark board 20, and a concave groove 19 is received on the surface 20 a of the second mark board 20 facing the first mark board 10. Since the bead 23 is provided, the window hole 14 of the first mark board 10 is arranged between the adjacent concave grooves 19, and the day number 25 of the second mark board 20 is arranged between the adjacent beads 23. Since the selected day number 25 faces the window hole 14 and the bead 23 is fitted into the concave groove 19, the first mark board 10 and the second mark board 20 are prevented from being displaced. Thereby, the position of the day number 25 with respect to the window hole 14 is reliably hold | maintained during the assembly | attachment operation | work of the 1st mark board 10 and the 2nd mark board 20, and the molten metal injection | pouring to a metal mold | die. (Effects corresponding to claim 3)

  The lower mold 3 is formed with a recessed portion 5 that accommodates the first mark plate 10 and the second mark plate 20 that are overlaid, and a screw hole 8 into which a set screw 30 is screwed is opened on the bottom surface 7. Since the surface 10a of the first mark board 10 is set so as to be flush with the wall surface 4 where the recess 5 is opened, the first mark board 10 and the second mark board 20 do not protrude from the wall surface 4, and die-cast products. In this case, the wall thickness of the lot mark display section 2 is not damaged (thinned) by the thickness of the first mark board 10 and the second mark board 20. (Effects corresponding to claim 4)

  The center hole 11 of the first mark board 10 has a countersunk shape, and the retaining screw 30 forms a conical surface in which the outer peripheral surface 33 of the head 31 is aligned with the inner wall 12 of the center hole 11 of the first mark board 10. Since the upper surface 32 is set so as to be flush with the surface 10a of the first mark board 10, the head 31 of the set screw 30 does not protrude from the wall surface 4 of the lower mold 3, and the wall thickness of the die-cast product is impaired. There is no. (Effect corresponding to claim 7)

  Since the outer peripheral surface 17 of the first mark board 10 is a conical surface that aligns with the inner wall 6 of the opening of the recess 5, the first mark board 10 and the second mark board 20 are fixed with screws 30 and the bottom surface 7 of the recess 5. Since the outer peripheral surface 17 and the inner wall 6 of the recess 5 are in intimate contact with each other, the occurrence of burrs at that portion is prevented. (Effects corresponding to claim 5)

In the above embodiment, the first mark board 10 and the second mark board 20 are attached to the lower mold in the mold. However, the first mark board 10 and the second mark board 20 may be attached to the upper mold according to the set part of the lot mark display section.
The position of the 1st mark board 10 and the 2nd mark board 20 is provided by providing the ditch | groove 19 in the back surface 10b of the 1st mark board 10, and providing the bead 23 in the surface 20a of the 2nd mark board 20, and fitting these. Although misalignment is prevented, a bead may be provided in the first mark board 10 and a concave groove may be provided in the second mark board 20.

Although the grouping of the day numbers to be engraved on the second mark board 20 is set to 8 days, it is not limited to this. For example, the grouping may be performed in units of 9 days or more, or in units of 7 days or less. However, in order to reduce the number of groups (the number of second mark boards 20), it is preferable to divide into groups of 8 days or more.
Although the day number is grouped by serial number, it does not have to be a serial number.
In addition, it is advantageous that the outer shape of the first mark board 10 and the second mark board 20 is circular as described above because the outer peripheral surface is conical and can be easily brought into close contact with the inner wall of the recess 5. It is not limited to this, and can be arbitrarily set as necessary, for example, a polygon corresponding to the unit number of days of day number grouping. In this case, the opening shape of the recess formed in the mold also corresponds to the same shape You can do it.

In the embodiment in which the first mark board 10 and the second mark board 20 are housed in the recess 5, the inner wall of the recess 5 is formed by making the outer peripheral surface of the first mark board 10 an inclined surface such as a cone as described above. As a modification, if the screw hole 8 of the bottom surface 7 is shifted from the center of the recess 5 by a predetermined amount, the set screw 30 penetrating the center hole 11 of the first mark board 10 is forcibly screwed. As a result, a radial compressive force is generated between the outer peripheral surface 33 of the head 31 and the inner wall 12 of the center hole 11, and the locking screw 30 is strongly loosened. (Effect corresponding to claim 6)
For example, if the nominal diameter of the first mark board 10 and the recess 5 is 20-30 mm, the tolerance of the diameter of the outer peripheral surface 17 of the first mark board 10 is 0− + 0.018 mm, and the tolerance of the diameter of the inner wall 6 of the recess 5 is 0−. By setting 0.017 mm and core misalignment of the screw hole 8 to 0.05 + −0.01 mm, at least 0.005 mm is compressed in one radial direction. The nominal diameter here is a value of the same predetermined distance from the surface 10a and the wall surface 4 of the first mark board 10.

In this case, the set screw 30 is centered on the center of the first mark board 10 by the conical surface of the head 31 and the center hole 11 regardless of the tolerance of the set screw 30 and the center hole 11. The second mark board 20 may have an outer diameter tolerance so that a gap is always formed between the second mark board 20 and the inner wall 6 of the recess 5.
The misalignment of the screw hole 8 creates a gap in the circumferential direction between the outer periphery of the first mark board 10 and the recess 5 and the molten metal flows in. However, since the gap is inclined along the conical surface, the die-cast product Does not come off when the mold is released, and as a result, burrs do not occur in the die-cast product.

In the embodiment, a recess 5 is provided in the lower mold 3 to accommodate the first mark board 10 and the second mark board 20, and both mark boards are not projected from the wall surface 4 of the lower mold 3. The wall thickness of the display portion is not reduced. However, when the wall thickness of the die-cast product is sufficiently large, the depth of the concave portion 5 is made shallow so that the stacked first mark board 10 and second mark board 20 are stacked. It is also possible to make a part project from the wall surface 4 of the lower mold 3 or to project the entire first mark board 10 and second mark board 20 from the wall surface 4 without providing a recess.
Similarly, when the wall thickness of the die-cast product is sufficiently large, the head 31 of the retaining screw 30 for fixing the first mark board 10 and the second mark board 20 to the mold also eliminates the conical surface of the outer peripheral surface 33 and removes the conical surface. You may make it protrude from the surface 10a of the 1-mark board | substrate 10. FIG.
When the first mark plate 10, the second mark plate 20, or the head 31 of the set screw 30 is protruded from the wall surface of the mold such as the lower die 3, a draft is given to each outer peripheral surface.

Although the embodiment has been described with reference to an example in which it is applied to a die casting die, the present invention can be applied to the provision of lot marks for other general casting products.
Moreover, although the example which displays the month Mm and the day Md by a number (month number / day number) as a lot mark was shown, it is not limited to this, and various information such as a factory, a model, a material and the like is displayed in combination. Can do. The lot mark may be expressed by alphabets or other characters in addition to numbers, or may be a picture.

The first and second mark shapes (month number / day number) on the first mark board 10 and the second mark board 20 are each engraved for ease of formation, but may be raised.
Further, although the hexagonal hole 36 is provided in the head 31 for screwing the set screw 30, it may be a straight groove or a cross groove for engaging the driver as in the conventional case. In the case of a straight groove, it is preferable to provide a draft angle.

DESCRIPTION OF SYMBOLS 1 Mold 2 Upper mold 3 Lower mold 4 Wall surface 5 Recess 6 Inner wall 7 Bottom surface 8 Screw hole 10 1st mark board 10a Surface 10b Back surface 11 Center hole 12 Inner wall 14 Window hole 15 Inner wall 17 Outer surface 18 Month number 19 Dent groove 20 First 2 mark board 20a surface 20b back surface 21 central hole 22 outer peripheral surface 23 bead 25 day number 30 set screw 31 head 32 upper surface 33 outer peripheral surface 34 thick shaft portion 35 screw portion 36 hexagonal hole 37 inner wall 40 die cast product 42 lot mark display portion 43 island 44 protrusion 45 circular bead Md day Mm month

Claims (8)

A lot mark giving structure for displaying a lot mark at a predetermined part of a cast product,
The first mark board and the second mark board, which are overlapped with each other, are fixed to the mold with a stop screw penetrating each center hole,
The first mark board has a first mark shape on the surface and a window hole,
The second mark board is provided with a plurality of second mark shapes at predetermined intervals in the circumferential direction of the surface at radial positions corresponding to the window holes, and is overlapped on the back surface of the first mark board.
The lot mark providing structure characterized in that a second mark shape selected from the plurality of second mark shapes faces the window hole. 2. The lot mark applying structure according to claim 1, wherein at least the second mark shape is formed by engraving. One of the opposing surfaces of the first mark board and the second mark board is provided with a bead extending in the radial direction at the predetermined interval in the circumferential direction, and a concave groove for receiving the bead is provided on the other of the opposing surface. Provided,
The lot mark applying structure according to claim 2, wherein the window hole and the second mark shape are arranged between the adjacent beads or the recessed grooves, respectively. The mold is formed with a concave portion for accommodating the first mark board and the second mark board, and a screw hole for screwing the set screw is opened on the bottom surface thereof.
The lot mark according to any one of claims 1 to 3, wherein the depth of the recess is set so that a surface of the first mark board is flush with a wall surface where the recess opens. Grant structure. The lot mark providing structure according to claim 4, wherein an outer peripheral surface of the first mark board is a conical surface aligned with an inner wall of the opening of the recess. The screw hole is opened by a predetermined amount from the center of the recess,
The lot mark applying structure according to claim 4 or 5, wherein a compressive force in a radial direction is generated between the set screw screwed into the screw hole and the first mark board. The central hole of the first mark board is dish-shaped,
The stop screw has a conical surface in which an outer peripheral surface of the head is aligned with an inner wall of the central hole of the first mark board, and an upper surface of the head is flush with a surface of the first mark board. The lot mark imparting structure according to any one of 1 to 6. The lot mark indicates a date,
The lot mark providing structure according to any one of claims 1 to 6, wherein the first mark shape is a month number and the second mark shape is a day number.

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