FR3115487A1 - Mold for producing a molded article - Google Patents

Abstract

Mold for producing a molded article The mold (10) comprises: - a first part (12); - a second part (14) movable relative to the first part (12) between a molding position and a separated position; - at least one guide element (18) of the second part (14), the second part (14) being guided by the guide element (18) between the molding position and the separated position; and - at least one guide housing (26) receiving the guide element (18) at least in the molding position. At least one guide member locking portion (18) and at least one guide housing locking portion (26) are movable between a locking position in which movement of the second portion (14) relative to the first part (12) is blocked and an unlocked position. Figure for abstract: Figure 1

Description

Mold for producing a molded article

The present invention relates to a mold for producing a molded article, of the type comprising:

- a first part;

- a second part movable relative to the first part in a direction of opening between a molding position in which the first part and the second part define between them a molding cavity and at least one spaced position in which the first part and the the second part are separated from each other;

- at least one guide element of the second part extending along a guide axis substantially parallel to the opening direction, the second part being guided by the guide element to move along the opening direction between the molding position and spread position; And

- at least one guide housing receiving the guide element at least when the second part is in the molding position.

Such a mold is, for example, used to produce motor vehicle parts by injection molding. The part to be produced is for example a vehicle trim element, such as a door panel, a dashboard body or the like.

The dimensioning of the mold, and in particular its size and its weight, is mainly determined by the pressure necessary to keep the mold closed during molding, in particular against the injection pressure of the molding material in the molding cavity, this injection pressure tending to separate the first and second parts of the mold from each other. The necessary pressure depends, among other things, on the surface of the molded article projected onto the mould.

To hold the mold in the closed position, it is known to add a locking system arranged to hold the first part and the second part against each other. Such locking makes it possible to increase the resistance of the mold to the injection pressure of the molding material. However, such a locking system complicates the structure of the mold and increases its size.

One of the aims of the invention is to overcome these drawbacks by proposing a simple mold capable of remaining in the closed position regardless of the injection pressure of the molding material in the molding cavity.

To this end, the invention relates to a mold of the aforementioned type in which at least one locking part of the guide element and at least one locking part of the guide housing are movable relative to each other between a locking position in which the movement of the second part relative to the first part is blocked and an unlocking position in which the second part is free to move relative to the first part.

The locking of the mold in the closed position is thus ensured by the cooperation between the guide element and the guide housing, which makes it possible to dispense with an additional and separate locking system. The combination of the guiding and locking functions on the guiding element and the guiding housing of the mold thus makes it possible to reduce the number of parts of the mold and therefore to reduce its complexity and its size.

According to optional characteristics of the invention, considered alone or according to any technically possible combination:

- the guide housing extends along a housing axis substantially parallel to the guide axis, the guide element being fixed in the opening direction with respect to the first part,

the guide element extending at least partly outside the guide housing when the second part is in its separated position and at least the locking part of the guide element extending into the guide housing when the second part is in its molding position;

- Between the locking position and the unlocking position, the locking part of the guide element is moved by relative rotation with respect to the locking part of the guide housing around the guide axis;

- the guide housing has a substantially cylindrical shape, the guide element being a cylindrical bar whose shape is substantially complementary to the shape of said guide housing;

- one between the locking part of the guide element and the locking part of the guide housing comprises at least one locking lug, the other defining at least one locking recess, the locking lug and the the blocking impression cooperating to prevent movement of the second part towards the separated position in the locking position;

- the locking part of the guide element includes the locking lug and the locking part of the guide housing defines the locking recess,

the guide element comprising an outer surface, the locking lug projecting radially from the outer surface,

the guide housing comprising an internal surface, the blocking recess extending over the internal surface,

the locking lug being housed in the locking recess in the locking position;

- the blocking impression comprises at least a first blocking surface extending recessed from the internal surface;

- the locking part of the guide element comprises at least one group of lugs, the lugs of the group of lugs being distributed uniformly around the guide axis;

- the locking part of the guide housing defines a plurality of locking indentations, each lug of a group of lugs being housed in a corresponding indentation in the locking position; And

- the indentations are distributed axially over a section of the guide housing and the groups of lugs are distributed axially over a section of the guide element.

Other aspects and advantages of the invention will appear on reading the following description, given by way of example and made with reference to the appended drawings, in which:

there is a simplified schematic sectional representation of a mold according to the invention, the section passing through two guide elements, the mold being in a separated position;

there is a representation similar to that of the except that the mold is in a molding position;

there illustrates two perspective representations of a housing for guiding the mold of the and 2; And

there illustrates two representations in perspective of a guiding element of the mold of the and 2.

With reference to and 2, a mold 10 for making a molded article (not shown) is disclosed.

The mold 10 comprises a first part 12 and a second part 14 movable relative to the first part 12 in an opening direction D between a separated position (visible on the ) and a molding position (visible on the ).

In the separated position, the first part 12 and the second part 14 are separated from each other so as to free up access between the two parts 12, 14 of the mold 10 to place objects therein or to remove them.

In the molding position, the first part 12 and the second part 14 define between them at least one molding cavity 16 having the shape of the article to be molded.

The first part 12 comprises a first molding surface 22.

The second part 14 comprises a second molding surface 24.

As illustrated on the , the first molding surface 22 and the second molding surface 24 delimit the molding cavity 16 in the molding position.

The molded article is intended to be molded in the mold cavity 16 from a molding material, for example, by injecting the molding material into the mold cavity 16. For this purpose, the mold 10 comprises all the elements necessary for this injection. The mold 10 comprises, for example, at least one injection nozzle (not shown) for the molding material opening into the molding cavity 16 and making it possible to inject the molding material into the molding cavity 16 to produce the article molded in the molding position. The pressure in the mold cavity 16 increases as molding material is injected into the mold cavity 16.

The mold 10 further comprises at least a first actuator (not shown), configured to move the second part 14 relative to the first part 12 between the molding position and the separated position. The first actuator is, for example, a press or a movable platen, for example, on a rail. When the first actuator is a press, the first actuator moves the second part 14 relative to the first part 12 and participates in the resistance to an injection pressure of the molding material in the molding position.

The mold 10 further comprises other elements not shown, conventional for this type of tooling, such as, for example, means for heating and/or cooling the molding cavity 16, thermal regulation channels or others. These various elements have not been represented on the and 2 for simplicity.

In the molding position, the first part 12 and the second part 14 are configured to resist the injection pressure of the molding material during molding to form the molded article. According to one example, when the first actuator is a press, the press participates in maintaining the first part 12 and the second part 14 in position by resisting the injection pressure of the molding material. The injection pressure is, for example, between 100 bars and 2500 bars.

The mold 10 further comprises at least one guide element 18 of the second part 14 and at least one guide housing 26 receiving the guide element 18 at least when the second part 14 is in the molding position.

The guide element 18 extends along a guide axis G-G' substantially parallel to the opening direction D. The guide element 18 allows good positioning of the second part 14 with respect to the first part 12 in the molding position so that the mold cavity 16 has the desired shape and that the tightness of the mold cavity 16 is ensured. The second part 14 is guided by the guide element 18 to move along the opening direction D between the molding position and the separated position. According to one embodiment, the guide element 18 is, for example, fixed along the opening direction D with respect to the first part 12 and the second part 14 moves towards the closed position by sliding on the guidance 18.

The guide element 18 is, for example, made of steel.

As will be described below, at least one locking part of the guide element 18 and at least one locking part of the guide housing 26 are movable with respect to each other between a locking position and a unlock position. As will be further described below, one between the locking part of the guide element 18 and the locking part of the guide housing 26 comprises at least one locking pin 46. The other between the part of locking of the guide element 18 and the locking part of the guide housing 26 defines at least one locking recess 32. For reasons of simplification, no locking lug 46 and no locking recess 32 is represented on the and 2.

The mold 10 comprises, for example, in addition, at least a second actuator (not shown), configured to move the locking part of the guide element 18 and/or the locking part of the guide housing 26 one relative to each other between the locking position and the unlocking position. The second actuator is, for example, a system comprising a motor rotating a belt. The belt drives, for example, in rotation the locking part of the guide element 18 and/or the locking part of the guide housing 26.

According to the embodiment illustrated in the , the guide housing 26 is a sheath arranged in the second part 14 when the guide element 18 is secured to the first part.

The guide housing 26 extends along a housing axis L-L' substantially parallel to the guide axis G-G'.

The guide housing 26 has, for example, a substantially cylindrical shape. In particular, the guide housing 26 comprises an internal surface 30 forming a substantially cylindrical envelope.

The guide housing 26 is, for example, made of steel.

With reference to the example of Fig. 3, the guide housing 26 defines at least one guide channel 31 and at least one locking recess 32. In particular, the locking part defines the at least one locking recess 32.

The guide channel 31 is, in particular, defined on the inner surface 30 of the guide housing 26, preferably recessed in the inner surface 30. The guide channel 31 forms a longitudinal groove made in the inner surface 30. The channel guide 31 extends substantially parallel to the housing axis L-L'. As illustrated on the , the guide housing 26 defines, for example, several guide channels 31. The guide channels 31 are, for example, uniformly distributed around the housing axis L-L'. For the sake of simplification, no guide channel 31 is shown on the and 2.

The blocking recess 32 extends over the inner surface 30 of the guide housing 26, preferably recessed on the inner surface 30. The locking recess 32 forms an orthoradial groove made in the inner surface 30. The recess blocking 32 communicates with at least one guide channel 31.

In particular, the blocking recess 32 comprises at least a first blocking surface 36. The first blocking surface 36 extends, for example, recessed from the internal surface 30. The first blocking surface 36 extends, for example, along a plane perpendicular to the housing axis L-L'. The first blocking surface 36 is substantially turned towards the outside of the mold 10 with respect to the first part 12 along the housing axis L-L'. The first blocking surface 36 opposes the movement of the second part 14 in the opening direction D towards the separated position in the locking position. The blocking recess 32 further comprises at least one opposite surface 38 facing the first blocking surface 36. The groove formed by the blocking recess 32 is thus delimited axially by the first blocking surface 36 and the opposite surface 38.

The locking part of the guide housing 26 defines, for example, at least one group 34 of blocking indentations 32. The indentations 32 of the group 34 are, for example, uniformly distributed around the axis of the housing L-L' , for example, at the same level of the guide housing 26 along the housing axis L-L'. By “at the same level”, it is understood that the cavities 32 of the group 34 are distributed in the same cross section of the guide housing 26, said cross section being orthogonal to the housing axis L-L′. The blocking surfaces 36 of the cavities 32 of the same group 34 extend, for example, in the same cross section of the guide housing 26, said cross section being orthogonal to the housing axis L-L′. Two adjacent cavities 32 of the same group 34 are separated from each other by at least one guide channel 31. A group 34 of blocking cavities 32 comprises, for example, between three blocking cavities 32 and five blocking fingerprints 32.

The locking part of the guide housing 26 defines, for example, several groups of cavities 34 distributed axially over a section of the guide housing 26. The guide housing 26 comprises, for example, between a group of cavities 34 and ten groups of footprints 34. By way of example, two groups of footprints 34 are illustrated in the .

According to the example illustrated on the at 3, the locking part of the guide housing 26 is formed by the entire guide housing 26, that is to say that the indentations 32 extend throughout the sheath illustrated in FIG. 3.

With reference to the , the guide element 18 is, for example, a cylindrical bar whose shape is substantially complementary to the shape of the guide housing 26. In particular, the guide element 18, in particular the locking part of the guide 18, comprises an outer surface 44 forming a substantially cylindrical envelope and at least one locking lug 46.

Locking lug 46 projects radially from outer surface 44.

The locking pin 46 has a dimension taken along the guide axis G-G' less than or equal, preferably strictly less, than a dimension of the locking recess 32 taken along the housing axis L-L' .

The locking part of the guide element 18 comprises, for example, at least one group 50 of lugs 46. The lugs 46 of the group of lugs 50 are, for example, uniformly distributed around the guide axis G -G'. For example, the lugs 46 of the group of lugs 50 are distributed uniformly around the guide axis G-G' at the same level of the guide element 18 along the guide axis G-G'. By "at the same level", it is understood that the lugs 46 of the group of lugs 50 are distributed in the same cross section of the guide element 18, said cross section being orthogonal to the guide axis G-G '.

The number of lugs 46 of a group of lugs 50 is, for example, equal to the number of guide channels 31 and the number of indentations 32 in a group 34 of blocking indentations 32 with which the lugs 46 are arranged to cooperate in the locking position.

The angular distribution of the lugs 46 of a group of lugs 50 around the guide axis G-G' is, for example, the same as the angular distribution of the indentations 32 around the housing axis L-L' and the same as the angular distribution of the guide channels 31.

The locking part of the guide element 18 comprises, for example, several groups of lugs 50 distributed axially over a section of the guide element 18. By way of example, two groups of lugs 50 are represented on there .

According to the example illustrated on the , 2 and 4, the locking part of the guide element 18 is formed by the whole of the guide element 18, that is to say that it is the whole of the guide element 18 which cooperates with the guide housing 26 in the locking position.

With reference to the , in the position separated from the second part 14, the guide element 18 extends at least partly outside the guide housing 26. With reference to the , in the molding position of the second part 14, at least the locking part of the guide element 18 extends into the guide housing 26.

The locking part of the guide element 18 and the locking part of the guide housing 26 are movable with respect to each other between the locking position in which the movement of the second part 14 with respect to the first part 12 is blocked and the unlocked position in which the second part 14 is free to move relative to the first part 12.

In the locking position, the locking in position of the second part 14 relative to the first part 12 allows the first part 12 and the second part 14 to withstand additional injection pressure of the molding material during molding to form the molded article. The additional injection pressure is, for example, between 10% and 100% of the required closing force. The necessary closing force is calculated according to the formula F=P x S where P is the injection pressure and S is the projected surface of the molded article on the second part 14. The injection pressure depends on the material of cast.

Between the locking position and the unlocking position, the locking part of the guide element 18 is moved by relative rotation with respect to the locking part of the guide housing 26 around the guide axis G-G' .

According to one embodiment, between the locking position and the unlocking position, the locking part of the guide element 18 is moved by rotation of the locking part of the guide element 18 around the axis guide G-G' with respect to the guide housing 26, the guide housing 26 being fixed with respect to the second part 14.

When the second part 14 is moved between its separated position and its molding position, the locking pin 46 moves in the guide channel 31. The guide channel 31 has a cross section whose shape is complementary to that of each locking pin 46 so that the locking pin 46 slides in the guide channel 31 when the second part 14 is moved between the separated position and the molding position.

When passing between the unlocking position and the locking position, the locking lug 46 moves relative to the locking recess 32, in the locking recess 32. Thus, when passing between the unlocking position and the locking position, the locking lug 46 moves relative to the locking part of the guide housing 26 between the guide channel 31 and the locking recess 32.

In the locking position, the locking lug 46 extends into the locking recess 32. The locking lug 46 and the locking recess 32 then cooperate to prevent the movement of the second part 14 towards the position ruled out. In particular, in the locking position, the lug 46 is housed in the blocking recess 32. The lug 46, and in particular a blocking surface of the lug 46 extending, for example, along a plane perpendicular to the guide axis G-G', then cooperates with the first blocking surface 36 of the blocking cavity 32 to block the movement of the second part 14 in the opening direction D.

In the locking position, each pin 46 of a group of pins 50 is housed in a corresponding cavity 32.

In the unlocked position, the locking lug 46 extends in the guide channel 31 outside the locking recess 32. The locking lug 46 then does not cooperate with the locking recess 32 so that the second part 14 is free to move relative to the first part 12.

According to the same cross-section of the guide element 18, a group of lugs 50 comprises, for example, three lugs 46 distributed every 120° around the guide axis G-G'. According to the same cross-section of the guide housing 26, the longitudinal channels 31 are, for example, distributed every 120° around the housing axis L-L' with an offset of 60° with respect to the position of the three lugs 46 of the lug group 50. The passage between the locking position and the unlocking position is then effected, for example, by a 60° rotation of the guide element 18 around the guide axis G-G' .

As illustrated on the and 2, the mold 10 comprises, for example, a plurality of guide elements 18. The mold 10 comprises, for example, between three guide elements 18 and twenty guide elements 18. The guide elements 18 are, for example , distributed around the first molding surface 22.

As illustrated on the and 2, the mold 10 comprises, for example, a plurality of guide housings 26. The mold 10 comprises, for example, between three guide housings 26 and twenty guide housings 26. The number of guide elements 18 is, for example, equal to the number of guide housings 26. The guide housings 26 are, for example, distributed around the second molding surface 24.

The second actuator is, for example, configured to move the at least one locking part of each guide element 18 and the at least one locking part of each guide housing 26 corresponding relatively to one another. other. According to a variant, each locking part of each guide element 18 is associated with a second actuator, which is for example formed by a rotary hydraulic jack.

In what follows, a method of using the mold 10 as described above for the production of a molded article is described.

Initially the mold 10 is in the separated position and in the unlocked position.

The first mold actuator 10 is actuated to move the second part 14 relative to the first part 12 from its spaced apart position to its molding position.

The second part 14 is then guided by each guide element 18 to move along the opening direction D to the molding position.

The second mold actuator 10 is actuated to move each locking portion of each guide element 18 and/or each locking portion of each guide housing 26 from the unlocked position to the locked position.

In the molding position, a molding material is injected into the mold cavity 16. The molded article is then formed by molding in the mold cavity 16.

When the molding of the molded article is completed, the second mold actuator 10 is actuated to move each locking part of each guide element 18 and/or each locking part of each guide housing 26 from the locking position to unlock position.

The first actuator of the mold 10 is then actuated to move the second part 14 relative to the first part 12 from its molding position to its separated position.

The second part 14 is then guided by each guide element 18 to move in the opening direction D to the separated position.

The molded article is then removed from the mold cavity 16.

According to another embodiment, the surface 38 opposite the first blocking surface 36 of the blocking recess 32 constitutes a second blocking surface. The second blocking surface is substantially turned towards the first part 12 along the housing axis L-L'. The locking lug 46 then has a dimension taken along the guide axis G-G' substantially equal to a dimension of the locking recess 32 taken along the housing axis L-L'. The locking recess 32 and the corresponding locking lug 46 then have complementary shapes so that in the locking position, the locking lug 46 matches the shape of the locking recess 32. Thus, in the locking position locking, the lug 46 cooperates with the first blocking surface 36 and the second blocking surface 38 to block the movement of the second part 14 in the opening direction D.

According to yet another embodiment, between the locking position and the unlocking position, the locking part of the guide housing 26 is moved by rotation of the locking part of the guiding housing 26 around the housing axis L -L' with respect to the locking part of the guide element 18, the guide element 18 being fixed with respect to the first part 12.

According to yet another embodiment, between the locking position and the unlocking position, the locking part of the guide element 18 and the locking part of the guide housing 26 are both moved relative to each other. the other by rotation respectively around the guide axis G-G' in one direction of rotation and around the housing axis L-L' in a contrary direction of rotation.

According to yet another embodiment, the guide element 18 defines each guide channel 31 and each blocking recess 32 and the guide housing 26 includes each blocking lug 46.

According to yet another embodiment, the guide element 18 comprises for example a fixed central rod extending along the guide axis G-G' and at least one movable sleeve carrying the locking lugs 46. The sleeve is , for example, mobile in rotation with respect to the central rod around the guide axis G-G'. The locking part of the guide element 18 is then formed by the sleeve.

According to yet another embodiment, the guide element 18 comprises a fixed proximal part integral with the first part 12 and a movable endpiece carrying the locking lugs 46. The endpiece is, for example, movable in rotation relative to the proximal part around the guide axis G-G'. The locking part of the guide element 18 is then formed by the tip.

According to yet another embodiment, the sheath which constitutes the guide housing 26 comprises a substantially cylindrical hollow body extending along the housing axis L-L' and integral with the second part 14 and at least one movable ring s 'extending around the housing axis L-L' in the hollow body and bearing the locking indentations 32. The ring is, for example, rotatable relative to the body around the housing axis L-L '. The locking part of the guide housing 26 is then, for example, the ring.

According to yet another embodiment, the guide housing 26 is a housing defined by the second part 14.

In the description above, the guide element 18 is presented as being fixed in the opening direction D with respect to the first part 12 and the guide housing 26 is presented as being arranged in the second part 14. It it is understood that the invention also relates to a mold 10 in which the guide element 18 is fixed along the opening direction D with respect to the second part 14 and in which the guide housing 26 is arranged in the first part 14 .

Thanks to the mold 10 according to the invention, it is possible, if necessary, to increase the pressure resistance of the mold 10. The invention therefore makes it possible to adapt the mold to a high injection pressure of the molding material.

The invention also makes it possible to reduce the resistance or power requirements of other elements of the mold, such as, for example, the power of the molding press. It is thus possible to use a press capable of providing less pressure than that required for molding in a conventional mould.

Said mechanical locking system is also compact since it is integrated on guide elements 18 of the second part of the mold 10 with respect to the first part of the mold 10.

Claims (10)

Mold (10) for producing a molded article, comprising:
- a first part (12);
- a second part (14) movable relative to the first part (12) in an opening direction (D) between a molding position in which the first part (12) and the second part (14) define between them a mold cavity (16) and at least one separated position in which the first part (12) and the second part (14) are separated from each other;
- at least one guide element (18) of the second part (14) extending along a guide axis (G-G') substantially parallel to the opening direction (D), the second part (14) being guided by the guide element (18) to move along the opening direction (D) between the molding position and the separated position; And
- at least one guide housing (26) receiving the guide element (18) at least when the second part (14) is in the molding position;
the mold (10) being characterized in that at least one locking part of the guide element (18) and at least one locking part of the guide housing (26) are movable relative to each other another between a locking position in which the movement of the second part (14) relative to the first part (12) is blocked and an unlocking position in which the second part (14) is free to move relative to the first part (12). Mold (10) according to Claim 1, in which the guide housing (26) extends along a housing axis (L-L') substantially parallel to the guide axis (G-G'), the element guide (18) being fixed in the opening direction (D) with respect to the first part (12),
the guide element (18) extending at least partly outside the guide housing (26) when the second part (14) is in its separated position and at least the locking part of the guide (18) extending into the guide housing (26) when the second part (14) is in its molding position. Mold (10) according to claim 1 or 2, wherein between the locking position and the unlocking position, the locking part of the guide member (18) is moved by relative rotation with respect to the locking part of the guide housing (26) around the guide axis (G-G'). Mold (10) according to any one of Claims 1 to 3, in which the guide housing (26) has a substantially cylindrical shape, the guide element (18) being a cylindrical bar whose shape is substantially complementary to the form of said guide housing (26). A mold (10) according to any one of claims 1 to 4, wherein one between the guide member locking portion (18) and the guide housing locking portion (26) comprises at least one blocking pin (46), the other defining at least one blocking imprint (32), the blocking pin (46) and the blocking imprint (32) cooperating to prevent the movement of the second part (14) to the retracted position in the locking position. A mold (10) according to claim 5, wherein the guide member locking portion (18) comprises the locking lug (46) and the guide housing locking portion (26) defines the blocking (32),
the guide element (18) comprising an outer surface (44), the locking pin (46) projecting radially from the outer surface (44),
the guide housing (26) comprising an internal surface (30), the locking recess (32) extending on the internal surface (30),
the locking lug (46) being housed in the locking recess (32) in the locking position. A mold (10) according to claim 6, wherein the blocking cavity (32) comprises at least a first blocking surface (36) extending recessed from the inner surface (30). A mold (10) according to claim 6 or 7, wherein the locking portion of the guide member (18) comprises at least one group (50) of lugs (46), the lugs (46) of the group of lugs (50) being distributed uniformly around the guide pin (G-G'). A mold (10) according to claim 8, wherein the locking portion of the guide housing (26) defines a plurality of locking indentations (32), each pin (46) of a group of pins (50) being housed in a recess (32) corresponding in the locking position. Mold (10) according to Claim 9, in which the cavities (32) are distributed axially over a section of the guide housing (26) and the groups of lugs (50) are distributed axially over a section of the guide element (18).