RU2845802C1 - Mould for automatic coupling body production - Google Patents

Abstract

FIELD: foundry production.

SUBSTANCE: invention relates to metallurgy (foundry production), in particular to the design of technological elements of a casting mould used in the manufacture of cast parts "Automatic coupling body". Mould for the automatic coupling body manufacturing contains the upper and lower mould halves from the compacted moulding material, connected along the parting line, runner system consisting of runner, riser, filling funnel and sump, heads cavities located on the upper half-mould, moulding core, which includes a head part with iconic sections, and tail part with iconic sections, also having section in form of rectangular section of constant height with transverse process ribs arranged with equal pitch perpendicular to axis of moulding core, and an end, in the upper half-mould there are ribs, a crimping groove and a cooler, in the upper half-mould and in the cavities for the head there are pricks with diameter of 6 to 8 mm, moulding core head part further comprises a recess forming a tenon for the lock holder, grooves forming bosses for the elevator, recess, which creates a shelf for the safety lock, a devastation, which is in the section a set of conjugated tangentially arcs of different radii, made both convexly and concavely, wherein this emptying is made by drawing with a slope inside the section, a cylindrical opening with a V-shaped protrusion, wherein the axis of the cylindrical opening is perpendicular to the axis of the moulding core, and faces have inclination of up to 5° relative to axis of cylindrical hole, on inner radius of engagement contour there is an insert from sand-chromite mixture, tail part of the moulding core additionally contains cavities that are located along the tail part, the end face is made in the form of an elliptical cylinder and has a step made on the sign part for the upper half-mould, in the transition zone between the head and tail parts, in the vertical and horizontal walls mating angles, anti-shrinkage ribs are located, made with a reduced pitch in range of 25 to 15 mm and passing from the foundry rod radius horizontal part into the vertical part along the radius, wherein transverse process ribs and anti-shrinkage ribs are made with thickness from 4 to 6 mm and depth from 10 to 15 mm, and transverse process ribs are made with equal pitch in range from 50 to 60 mm.

EFFECT: decreased amount of rejects in the production of castings.

6 cl, 5 dwg

Description

The claimed invention relates to the field of metallurgy (foundry production), in particular to the design of technological elements of a casting mold used in the manufacture of cast parts of the “Automatic coupling body”.

The problem, which the claimed invention is aimed at solving, is that when manufacturing the part "Automatic coupling housing", the commonly used casting molds with casting cores forming the internal cavity of the casting do not exclude the formation of casting defects, such as distortion of the geometry of the internal cavities of the part, flooding, since they are not firmly and securely fastened in the casting mold, as a result, the casting cores shift from their place during the pouring process, while the size of one wall of the part decreases, and the other increases, in addition, the formation of hot cracks, shrinkage cavities in the casting is not excluded due to an insufficient number of elements in the design of the casting cores that prevent the occurrence of these defects.

The task, which the claimed invention is aimed at solving, is to improve the filling of the casting mold with liquid melt; increase the accuracy of casting, and reduce the labor intensity of auxiliary operations associated with the preparation of the casting mold for pouring.

The technical result achieved from the declared technical solution is a reduction in the level of defects in the production of castings.

The prior art discloses a design of a casting mold for an automatic coupling housing (website https://studbooks.net/2555636/tovarovedenie/izgotovlenie_detaley_avtostsepnogo ustroystva), containing a rod consisting of several half-rods forming a head part including a recess forming a tenon for a lock holder, a sign part of the rod of the upper half-mold for fixing and positioning the rod when covering the upper half-mold, containing a projection to ensure the operation of the riser, a sign part of the rod of the lower half-mold for positioning the rod when installing it in the mold and keeping it from falling to the sides during transportation of the mold, and a tail part having a rectangular cross-section of constant height, containing an end element made in the form of an elliptical cylinder.

Also known from the prior art is a design of a casting mold for manufacturing automatic coupling housings (patent RU 187005, B22C 9/00, published 13.02.2019, Bulletin No. 9), consisting of a head and a tail with a jumper at the end, containing lower and upper half-molds made of hardened molding material, made with cavities that form casting cavities when the said half-molds are closed, forming the outer contours of the automatic coupling housings, rods forming the inner contours of the automatic coupling housings, and a gating-feed system including a riser, gating passages and direct feed risers located above the head sections of the automatic coupling housings, characterized in that the lower and upper half-molds are made by vacuum-film molding and contain hardened bulk molding material enclosed in upper and lower flasks and sealed with synthetic films, the upper and lower flasks are equipped with vacuum tubes, located evenly along the length of the said flasks and parallel to each other, while above the sections of the head and the web of the tail of the automatic coupler housings, shells are installed for forming direct feed risers, and above the shells of the direct feed risers, models of thrusts are installed.

In this case, the casting mold for manufacturing the automatic coupling housings shown in Fig. 1 - Fig. 5 includes rods that form the internal contours of the automatic coupling housings, made in one piece and consisting of a head part, a sign part of the rod of the upper half-mold for fixing and positioning the rod when covering the upper half-mold, a sign part of the rod of the lower half-mold for positioning the rod when installing it in the mold and holding it from falling to the sides during transportation of the mold, and a tail part having a rectangular cross-section of constant height, containing transverse technological ribs located perpendicular to the axis of the rod, having an equal pitch over the entire surface of the tail part.

The design of this casting mold was adopted by the authors of the claimed invention as a prototype.

Disadvantages of the analogue and prototype:

- casting molds with casting cores that form the internal cavity of the automatic coupling body do not exclude distortion of the geometry of the internal cavities of the part, since these casting cores are not sufficiently firmly and securely fastened in the casting mold, as well as the formation of casting defects, such as floods, hot cracks, shrinkage cavities due to an insufficient number of elements in the casting core design that prevent the occurrence of these defects.

The stated problem is solved, and the specified technical result is achieved, in that a casting mold for producing an automatic coupling housing, containing upper and lower mold halves made of compacted molding material, connected along a parting line, a gating system consisting of a gating run, a riser, a pouring funnel and a sump, cavities for a riser, located on the upper half of the mold, a casting core including a head part with sign sections and a tail part with sign sections, also having a section in the form of a rectangular section of constant height, with transverse technological ribs located with an equal pitch, perpendicular to the axis of the casting core and an end, characterized in that ribs, a crimping groove and a cooler are made in the upper half of the mold, pricks with a diameter of 6 mm to 8 mm are made in the upper half of the mold and in the cavities for the riser, the head part of the casting core additionally contains a recess, grooves, a recess, an emptying, which in section is a set of conjugate tangentially arcs of different radii, made both convex and concave, wherein this emptying is made by drawing with a slope inward of the section, a cylindrical hole with a V-shaped protrusion, wherein the axis of the hole is perpendicular to the axis of the casting core, and the faces have a slope of up to 5º relative to the axis of the cylindrical hole, an insert made of sand-chromite mixture is installed on the inner radius of the engagement contour, the tail part of the casting core additionally contains cavities that are located along the tail part, the end is made in the form of an elliptical cylinder and has a step made on the sign part for the upper half of the mold, in the transition zone between the head and tail parts in the corners of the conjugation of the vertical and horizontal walls there are anti-shrinkage ribs made with a reduced pitch in the range from 25 mm to 15 mm and passing from the horizontal part of the radius of the casting rod into the vertical part along the radius, while the transverse technological ribs and anti-shrinkage ribs are made with a thickness of 4 to 6 mm and a depth of 10 to 15 mm, and the transverse technological ribs are made with an equal pitch in the range from 50 mm to 60 mm.

In a particular embodiment of the casting mold for manufacturing the automatic coupling body, the transverse technological ribs and anti-shrinkage ribs on the casting rod are made 6 mm thick and 15 mm deep.

In a particular version of the casting mold for manufacturing the automatic coupling body, the transverse technological ribs on the casting rod are made with an equal pitch of 55 mm.

In a particular version of the casting mold for manufacturing the automatic coupling body, the anti-shrinkage ribs on the casting rod are made with a reduced pitch of 20 mm.

In a particular version of the casting mold for manufacturing the automatic coupling body, the diameter of the punctures made in the upper half of the mold and in the cavities for the riser is 6 mm.

In a particular version of the casting mold for manufacturing the automatic coupling body, one prick is made in each cavity for the riser.

The essence of the claimed invention is explained by graphic materials:

Fig. 1 – casting mold (in three-dimensional representation);

Fig.2 – casting core (front view);

Fig.3 – casting core (rear view);

Fig. 4 – casting core (location of transverse technological ribs relative to the axis of the casting core);

Fig. 5 – casting core (location of the cylindrical hole relative to the axis of the casting core).

The casting mould comprises an upper (14) and a lower mould halves (15) made of compacted moulding material, connected along a parting line (16), a gating system consisting of a gating passage (17) and a pouring funnel (18), a riser (19) and a sump (20) made of ceramic material, cavities for a riser (21) located on the upper half of the mould (14), in the upper half of the mould (14) and in the cavities for a riser (21) gas splitters (22) with a diameter of 6 mm to 8 mm are made, in the upper half of the mould (14) ribs (23), a compression groove (24) and a cooler (25) are also made, a casting core (26) including a head part (1) with sign sections and a tail part (2) with sign sections, also having a section in the form of a rectangular section of constant height, cavities (3) forming stiffening ribs, which are located along the tail section, a recess (4) forming a tenon for the lock holder, grooves (5) forming lugs for the lifter, a notch (6) forming a shelf for the safety catch, an emptying (7) which is in cross-section a set of conjugate tangentially arcs of different radii, made both convex and concave, wherein this emptying is made by drawing with a slope inward of the cross-section, a cylindrical opening (8) with a V-shaped protrusion to prevent the rod from rotating along the axis, intended for installing a sand rod forming a hole into which the lifter roller is installed, wherein the axis of the opening is perpendicular to the axis of the casting rod, and the faces have a slope of up to 5° relative to the axis of the cylindrical opening (8), an insert made of a sand-chromite mixture (not shown) is installed on the inner radius of the engagement contour (13), the end is made in the form of an elliptical cylinder (9) and has a step (10) to ensure operation profit, made on the sign part for the upper half of the mold, in the transition zone between the head and tail parts in the corners of the junction of the vertical and horizontal walls there are anti-shrinkage ribs (12), made with a reduced pitch in the range from 25 mm to 15 mm and passing from the horizontal part of the rod radius to the vertical part along the radius, wherein the transverse technological ribs (11) and anti-shrinkage ribs (12) are made with a thickness of 4 to 6 mm and a depth of 10 to 15 mm, and the transverse technological ribs (11) are made with an equal pitch in the range from 50 to 60 mm.

The casting mold works as follows.

The upper (14) and lower half-molds (15) are made using a casting pattern. To make the upper (14) and lower (15) half-molds, a molding mixture of quartz sand and ceramic elements are used: a riser (19) and a sump (20). A casting core (26) and a core (not shown) making a hole for the lift roller are also made.

Next, before installing the casting core (26) into the casting mold, a non-stick coating is applied to the recess (4) of the groove (5), the notch (6), the end (9), and to the inner radius of the engagement contour (13).

Next, a casting core (26) is installed in the imprint of the lower half-mold (15) obtained by the model. A pouring funnel (18) is also installed in the upper half-mold (14). In the imprint of the upper half-mold (14), there are two cavities for risers (21). In the upper half-mold (14), gas splitters (22) are made in the form of openings that provide ventilation of the casting mold when it is poured with liquid metal. In each cavity for a riser (21), at least one gas splitter (22) is made. The diameter of the gas splitters (22) is from 6 to 8 mm. On the upper half-mold (14), ribs (23) are made to prevent the appearance of hot cracks in the casting, and a cooler (25) is installed on the section located in the transition zone, between the head (1) and tail (2) parts of the casting core (26), to create directional solidification of the casting. In addition, to prevent metal flooding, a crimping groove (24) is made in the recess on the sign part of the upper half of the mold (14), which, when assembling the casting mold, forms a sand seal, but does not destroy the sign part of the casting mold.

Then, a rod (not shown) is installed in the cylindrical hole (8) with a V-shaped protrusion, making a hole for the lift roller in the casting of the "automatic coupling body". When this rod is installed in the cylindrical hole (8) with a V-shaped protrusion, its reliable installation and fixation horizontally and vertically is ensured.

The casting core (26), installed in the lower half-mold (15), is covered by the upper half-mold (14) in such a way that the marked sections located on the head part (1) and the tail part (2) of the casting core (26) coincide with the corresponding recesses on the casting mold. After assembling the casting mold, it is filled with liquid metal (liquid steel) through the gating system and the feeder into the gap formed between the casting mold and the casting core (26) in such a way that the head (1) and tail (2) parts of the casting core (26) come into contact with the liquid metal on all sides except for the marked sections of the casting core (26). During the process of crystallization of liquid metal, the thin walls and protruding elements of the casting, including those formed by transverse technological ribs (11), anti-shrinkage ribs (12), cavities (3) forming stiffening ribs, which are located along the tail part (2) of the casting core (26), are the first to crystallize. Due to the fact that these elements of the casting crystallize earlier than the main part of the casting, this prevents the occurrence of hot cracks during the transition from the vertical part of the casting to the horizontal part.

On the inner radius of the engagement contour (13) using an insert made of a sand-chromite mixture, the crystallization process is also accelerated along the entire plane of contact with this insert, due to the higher thermal conductivity of chromium sand in comparison with quartz sand, which ensures the absence of shrinkage cavities in this section of the casting.

During the further process of crystallization of the casting, the metal begins to shrink (linear shrinkage of steel is 2%) and, due to the presence of emptying (7), acceptable ductility of the massive head part (1) of the casting core (26) is ensured, and the formation of stresses and cracks in the casting is also excluded.

The presence of a step (10) in the design of the casting core (26) ensures the fixation of the casting core (26) in the upper half-mold (14), and also ensures the possibility of high-quality impregnation of the tail part of the casting without obstructing the operation of the riser.

Example: The production of the casting "automatic coupling body" from 20GL steel is carried out as follows.

The upper (14) and lower (15) half-moulds are made using a casting pattern. To make the upper (14) and lower (15) half-moulds, a moulding mixture of quartz sand and ceramic elements is used: a riser (19) and a sump (20). A casting core (26) and a core (not shown) making a hole for the lift roller are also made.

Before installing the casting core (26) into the casting mold, a non-stick coating is applied to the recess (4) of the groove (5), the notch (6), the end (9) and to the inner radius of the engagement contour (13).

Next, a casting core (26) and ceramic elements of the gating system are installed in the imprint of the lower half-mold (14) obtained by the model. Ceramic elements of the gating system are also installed in the upper half-mold (14). In the imprint of the upper half-mold (14), there are two cavities for risers (21). In the upper half-mold (14), gas splitters (22) are made in the form of holes, 6 mm in diameter, providing ventilation of the casting mold when it is poured with liquid metal. In each cavity for a riser (22), a gas splitter (22) with a diameter of 6 mm is made. On the upper half-mold (14), ribs (23) are made to prevent the appearance of hot cracks in the casting, and a cooler (25) is installed on the section located in the transition zone, between the head (1) and tail (2) parts of the casting core (26), to create directional solidification of the casting. In addition, to prevent metal flooding, a crimping groove (24) is made in the recess on the sign part of the upper half of the mold (14), which, when assembling the casting mold, forms a sand seal, but does not destroy the sign part of the casting mold.

Then, a rod (not shown) is installed in the cylindrical opening (8) with a V-shaped protrusion, making an opening for the lift roller in the casting "automatic coupling housing". The casting core (26), installed in the lower half-mold (15), is covered with the upper half-mold (14) in such a way that the symbolic sections located on the head part (1) and the tail part (2) of the casting core (26) coincide with the corresponding recesses on the casting mold. After assembling the casting mold, it is poured with 20GL steel by gravity through the gating system and the feeder into the gap formed between the casting mold and the casting core (26) in such a way that the head (1) and tail (2) parts of the casting core (26) come into contact with the liquid metal on all sides except for the symbolic sections of the casting core (26).

During the process of crystallization of liquid metal, the thin walls and protruding elements of the casting crystallize first, including those formed by transverse technological ribs (11) made with an equal pitch of 55 mm, anti-shrinkage ribs (12) made with a reduced pitch of 20 mm and cavities (3). In this case, the transverse technological ribs (11) and anti-shrinkage ribs (12) are made 6 mm thick and 15 mm deep. Due to the fact that these elements of the casting crystallize earlier than the main part of the casting, this prevents the occurrence of hot cracks during the transition from the vertical part of the casting to the horizontal part.

On the inner radius of the engagement contour (13), due to the use of an insert made of sand-chromite mixture, the absence of shrinkage cavities in this section of the casting is ensured.

The presence of an emptying (7) in the design of the casting core (26) ensures acceptable flexibility of the massive head part (1) of the casting core (26), and also eliminates the formation of stresses and cracks in the casting.

The presence of a step (10) in the design of the casting core (26) ensures the fixation of the casting core (26) in the upper half-mold, and also ensures the possibility of high-quality impregnation of the tail part of the casting without obstructing the operation of the riser.

Due to the fact that the casting core (26) is made of a single piece, it is securely fastened in the casting mold, the assembly of the casting mold is carried out without disturbances, the casting core (26) does not move from its place during the process of pouring metal, and the dimensional part of the casting is without deviations.

The design of the casting mold ensures smooth filling of the two “coupling body” castings with metal.

Accordingly, the use of this casting mold helps to reduce the level of defects in the production of castings.

Thus, the probability of casting defects is significantly reduced: when producing the annual volume of “automatic coupling housing” parts (20,000 pieces), casting defects decreased by 2% to 3% compared to previously used casting rods.

The claimed invention is used in the foundries of the enterprise JSC Scientific and Production Corporation Uralvagonzavod and has confirmed its technical and economic efficiency.

Claims (6)

1. A casting mold for producing an automatic coupling housing, comprising upper and lower halves of a mold made of compacted molding material connected along a parting line, a gating system consisting of a gating passage, a riser, a pouring funnel and a sump, cavities for a riser located on the upper half of the mold, a casting core including a head part with sign sections and a tail part with sign sections, which also has a section in the form of a rectangular section of constant height with transverse technological ribs located with an equal pitch perpendicular to the axis of the casting core, and an end, characterized in that ribs, a compression groove and a cooler are made in the upper half of the mold, pricks with a diameter of 6 to 8 mm are made in the upper half of the mold and in the cavities for the riser, the head part of the casting core additionally contains a recess forming a tenon for the lock holder, grooves forming bosses for the lift, a recess creating a shelf for the fuse, an emptying which is in the cross-section a set of conjugate tangentially arcs of different radii, made both convex and concave, and this emptying is made by drawing with a slope inward of the cross-section, a cylindrical hole with a V-shaped protrusion, and the axis of the cylindrical hole is perpendicular to the axis of the casting core, and the faces have a slope of up to 5° relative to the axis of the cylindrical hole, an insert made of sand-chromite mixture is installed on the inner radius of the engagement contour, the tail part of the casting core additionally contains cavities which are located along the tail part, the end is made in the form of an elliptical cylinder and has a step made on the sign part for the upper half of the mold, in the transition zone between the head and tail parts in the corners of the conjugation of the vertical and horizontal walls there are anti-shrinkage ribs made with a reduced pitch in the range from 25 to 15 mm and transitional from the horizontal part of the radius of the casting core to the vertical part along the radius, wherein the transverse technological ribs and anti-shrinkage ribs are made with a thickness of 4 to 6 mm and a depth of 10 to 15 mm, and the transverse technological ribs are made with an equal step in the range of 50 to 60 mm. 2. A casting mold for manufacturing an automatic coupling body according to paragraph 1, characterized in that the transverse technological ribs and anti-shrinkage ribs of the casting core are made 6 mm thick and 15 mm deep. 3. A casting mold for manufacturing an automatic coupling body according to paragraph 1, characterized in that the transverse technological ribs of the casting core are made with an equal pitch of 55 mm. 4. A casting mold for manufacturing an automatic coupling body according to paragraph 1, characterized in that the anti-shrinkage ribs of the casting core are made with a reduced pitch of 20 mm. 5. A casting mold for manufacturing an automatic coupling body according to paragraph 1, characterized in that the diameter of the punctures made in the upper half of the mold and in the cavities for the riser is 6 mm. 6. A casting mold for producing an automatic coupling body according to paragraph 1, characterized in that one prick is made in each cavity for the riser.