CN116251930A

CN116251930A - Gravity casting device

Info

Publication number: CN116251930A
Application number: CN202310103996.8A
Authority: CN
Inventors: 叶月湖; 郑金金; 林建勇
Original assignee: ZHEJIANG JIULONG MACHINERY CO Ltd
Current assignee: ZHEJIANG JIULONG MACHINERY CO Ltd
Priority date: 2023-01-31
Filing date: 2023-01-31
Publication date: 2023-06-13

Abstract

The application discloses a gravity casting device, which relates to the technical field of gravity casting and comprises a frame, wherein the frame is provided with a bearing assembly for mounting a die, the die comprises an upper die and a lower die, the upper die and the lower die are clamped to form a cavity, the outer wall of the lower die is provided with a liquid inlet groove, and the liquid inlet groove is communicated with the cavity; the bearing assembly comprises a bearing seat hinged to the frame, an installation seat connected to the bearing seat in a sliding mode and a first hydraulic cylinder driving the installation seat to be close to the bearing seat, the frame is further provided with a second hydraulic cylinder, and the second hydraulic cylinder is used for driving the bearing assembly to overturn so that the die overturns to guide molten metal in the liquid inlet groove into the cavity. Through the upset of pneumatic cylinder two drive bearing assembly, realized the setting of feed liquor groove lateral wall, improve the existence of mount pad and lead to the more complicated condition of last mould feed liquor hole design requirement for actual casting operation is more convenient.

Description

Gravity casting device

Technical Field

The present application relates to the field of gravity casting technology, and more particularly, to a gravity casting device.

Background

Gravity casting refers to a process in which molten metal is injected under the action of earth gravity. Gravity casting methods are required for aluminum castings of engines, such as engine water pipes and other blanks.

The gravity casting machine comprises a support fixed on a base, a core pulling oil cylinder is fixed on the base, a die platform is fixed at the upper end of a piston rod of the core pulling oil cylinder, fixed templates are symmetrically arranged on the left side and the right side of the upper end of the support, guide sleeves are respectively arranged at four corners of the fixed templates, guide posts penetrate through the guide sleeves to be in sliding fit with the guide sleeves, the rear ends of the guide posts are fixedly connected with a connecting plate, the front ends of the guide posts are fixedly connected with the movable templates, a die closing oil cylinder is fixed on the fixed templates, the piston rod of the die closing oil cylinder extends forwards to be fixedly connected with the movable templates, upright posts are respectively arranged at the four corners of the support, mounting seats are fixed at the top ends of the upright posts, lifting oil cylinders are arranged right above the corresponding die platform on the mounting seats, and matched guide posts and the guide sleeves are arranged around the lifting oil cylinder.

The gravity casting device needs molten metal to flow into a cavity for forming under the action of gravity, when the gravity casting machine is adopted, the top end of the upper die of the die is required to be provided with a liquid inlet hole for liquid to be led in based on the requirement of molten metal filling, but the position of the liquid inlet hole is staggered with the mounting seat based on the existence of the mounting seat, so that the design of the upper die of the die is complex, and the improvement is needed.

Disclosure of Invention

In order to improve the condition that the design requirement of an upper die liquid inlet hole is complex due to the existence of a mounting seat, the application provides a gravity casting device.

The application provides a gravity casting device adopts following technical scheme:

the gravity casting device comprises a frame, wherein the frame is provided with a bearing assembly for mounting a die, the die comprises an upper die and a lower die, the upper die and the lower die are clamped to form a cavity, the outer wall of the lower die is provided with a liquid inlet groove, and the liquid inlet groove is communicated with the cavity; the bearing assembly comprises a bearing seat hinged to the frame, an installation seat connected to the bearing seat in a sliding mode and a first hydraulic cylinder driving the installation seat to be close to the bearing seat, the frame is further provided with a second hydraulic cylinder, and the second hydraulic cylinder is used for driving the bearing assembly to overturn so that the die overturns to guide molten metal in the liquid inlet groove into the cavity.

Through the technical scheme, the bearing assembly is hinged, the hydraulic cylinder II drives the bearing assembly to overturn, in actual use, the upper die is firstly installed on the installation seat, the lower die is installed on the bearing seat, after the hydraulic cylinder I drives the installation seat to move downwards so that the upper die and the lower die are assembled, the liquid inlet groove protrudes out of the outer wall of the die, at the moment, an operator pours metal liquid into the liquid inlet groove, then drives the bearing assembly to overturn through the hydraulic cylinder II so that the liquid inlet groove is positioned above the die cavity, in the overturning process, the metal liquid in the liquid inlet groove pours into the die cavity, after the metal liquid is completely filled into the die cavity, after the metal liquid is solidified, the hydraulic cylinder II drives the bearing assembly to overturn, then the hydraulic cylinder drives the installation seat to be away from the bearing seat so that the upper die and the lower die are separated, and the operator can take out the workpiece from the die cavity area of the lower die. Through the upset of pneumatic cylinder two drive bearing assembly, realized the setting of feed liquor groove lateral wall, improve the existence of mount pad and lead to the more complicated condition of last mould feed liquor hole design requirement for actual casting operation is more convenient.

Optionally, the frame is provided with a limiting part, and the limiting part is arranged so that the liquid inlet groove is located right above the cavity when the liquid inlet groove is propped against by the bearing assembly.

Through above-mentioned technical scheme, set up spacing portion, carry out spacingly through spacing portion to the upset volume of bearing assembly for actual use is more convenient.

Optionally, the frame is provided with a supporting part, the bearing seat is provided with a supporting block, and when the supporting block supports against the supporting part, the upper die is located right above the lower die.

Through above-mentioned technical scheme, set up to lean on portion and lean on the piece, when leaning on the portion and lean on the piece, go up the mould and just lie in directly over the lower mould for the upset location of bearing assembly is more accurate.

Optionally, bear the seat and slide and connect in the thimble, the slip direction of thimble with the slip direction of mount pad is parallel, it still is equipped with the driving piece to bear the seat, the driving piece is used for the drive the thimble penetrates in the die cavity of lower mould is ejecting the work piece towards last mould direction.

Through the technical scheme, the workpiece in the cavity of the lower die can be ejected out through the stator, so that the demolding operation of the workpiece is more convenient.

Optionally, the thimble is provided with a plurality of thimble; the novel ejector pin comprises a plate body, and is characterized by further comprising ejector pins, wherein the ejector pins are fixed on the plate body, and the driving piece drives the plate body to move so as to drive the ejector pins to move.

Through above-mentioned technical scheme, the plate body connects a plurality of thimble for the removal of each thimble is more synchronous, and then makes the drawing of patterns more convenient.

Optionally, the driving piece includes set up in the actuating cylinder of bearing seat, set up the drive plate of actuating cylinder piston rod and set up in a plurality of actuating levers of drive plate, each the actuating lever is used for supporting the plate body.

Through the technical scheme, the driving oil cylinder drives the driving plate to move so as to drive the driving rod to move, and the driving rod abuts against the plate body, so that a plurality of points apply force to the plate body at the same time, and the plate body drives the ejector pin to eject a workpiece from the lower die more stably.

Optionally, the plate body still is equipped with the reset lever, the reset lever slides and wears out the top of lower mould, the position of reset lever with the position of die cavity staggers, when last mould with the lower mould compound die, go up the mould and support and press the reset lever makes the thimble with lower mould intracavity wall parallel and level.

Through above-mentioned technical scheme, set up the release lever, when the compound die, press the release lever to release lever upper end and lower mould up end parallel and level through last mould, the upper end and the lower model intracavity wall parallel and level of thimble this moment for the thimble does not outstanding die cavity inner wall, makes holistic shaping more stable.

Optionally, the driving piece is an air cylinder, and a piston rod of the air cylinder is used for pushing the plate body;

the frame is provided with an abutting part, the bearing seat is provided with an abutting block, and when the abutting block abuts against the abutting part, the upper die is positioned right above the lower die;

the piston is characterized in that a piston cavity is arranged in the abutting part, a piston head is connected in the piston cavity in a sliding manner, a dowel bar is fixed on the piston head, the dowel bar slides upwards to penetrate through the abutting part, the piston cavity is communicated with the inner cavity of the cylinder, when the abutting block abuts against the abutting part to enable the dowel bar to be pressed to be flush with the upper end face of the abutting part, the communicating area between the piston cavity and the inner cavity of the cylinder becomes smaller, so that the pressure rise is used for driving a piston rod of the cylinder to eject, and at the moment, when the upper die is far away from the lower die, the ejector pin drives a workpiece to be attached to the upper die to eject under the action of the cylinder.

Through the technical scheme, after the workpiece is formed, the bearing assembly is turned over to a state that the abutting block abuts against the abutting part, at the moment, the dowel bar is compressed to the upper end face to be parallel to the abutting part, when the mounting seat drives the upper die to move, the piston rod of the driving cylinder is pushed out by the pressure to drive the thimble to push out the workpiece out of the cavity of the lower die, and the workpiece is synchronously moved when being pushed out, until the upper die is separated from the workpiece. The workpiece is supported through the upper die when being ejected, so that the condition that the workpiece is bumped with the ejector pin due to inertial movement when the workpiece is ejected by the ejector pin is reduced, and the workpiece is more convenient to demould.

Optionally, the bearing assembly is further provided with a pressure detection unit, the pressure detection unit comprises a pressure sensor arranged on the lower end face of the propping block, a controller electrically connected with the pressure sensor and a display electrically connected with the controller, and the pressure detection unit is used for detecting the propping force between the dowel bar and the propping block.

Through above-mentioned technical scheme, design pressure detection unit, pressure detection unit detects the dowel bar and support the tight power of leaning on between the piece, when last mould and lower mould compound die, the tight power of support through pressure detection unit feedback pushes away the compression volume of the piston rod of drive cylinder, and then can detect the travel of reset lever, and then detect the compound die degree between last mould and the lower mould, when the compound die is not put in place because the shaping waste material leads to the compound die between going up mould and the lower mould, pressure detection unit can in time feed back the result, and then make the compound die of going up mould and lower mould more have the guarantee for the operation is more stable.

In summary, the present application includes at least one of the following beneficial technical effects:

(1) The second hydraulic cylinder drives the bearing assembly to turn over, so that the arrangement of the outer side wall of the liquid inlet groove is realized, the condition that the design requirement of the liquid inlet hole of the upper die is complex due to the existence of the mounting seat is improved, and the actual casting operation is more convenient;

(2) The ejector pin, the plate body and the reset rod are arranged, so that the stator is reset more conveniently;

(3) By arranging the piston rod, the piston head and the dowel bar, the situation that the workpiece collides with the ejector pin due to inertial movement when the workpiece is ejected out by the ejector pin is reduced, and the workpiece is more convenient to demould.

Drawings

FIG. 1 is a schematic overall structure of a first embodiment;

FIG. 2 is a schematic diagram showing a mold opening state of a mold according to the first embodiment;

FIG. 3 is a schematic diagram illustrating a carrier assembly in a tilted state according to the first embodiment;

FIG. 4 is a schematic diagram of a driving member according to the first embodiment;

FIG. 5 is a schematic diagram of a second embodiment;

fig. 6 is a schematic diagram of a driving member structure according to the second embodiment.

Reference numerals: 1. a frame; 2. a carrier assembly; 21. a bearing seat; 22. a mounting base; 3. a guide rod; 4. a mounting plate; 5. a first hydraulic cylinder; 6. a mold; 61. an upper die; 62. a lower die; 621. a liquid inlet tank; 7. a second hydraulic cylinder; 8. an abutment block; 9. an abutting portion; 10. a limit part; 11. a thimble; 12. a plate body; 13. a reset lever; 14. a driving member; 141. a driving oil cylinder; 142. a driving plate; 143. a driving rod; 144. a cylinder; 15. a piston chamber; 16. a piston head; 17. a dowel bar; 18. a pressure detection unit; 181. a pressure sensor; 182. a display.

Detailed Description

The present application is described in further detail below with reference to the accompanying drawings.

The embodiment of the application discloses a gravity casting device.

Examples:

a gravity casting device, see fig. 1, comprises a frame 1, wherein the frame 1 is provided with a bearing assembly 2, and the bearing assembly 2 comprises a bearing seat 21 and a mounting seat 22. The bearing seat 21 is hinged to the frame 1, and the hinge axis of the bearing seat 21 is horizontal. The installation seat 22 is connected onto the bearing seat 21 in a sliding manner, and the four guide rods 3 are fixed onto the bearing seat 21, the length direction of each guide rod 3 is perpendicular to the end face of the bearing seat 21 facing the installation seat 22, each guide rod 3 is penetrated through the installation seat 22 in a sliding manner, and the installation seat 22 is connected onto the guide rods 3 in a sliding manner along the length direction of the guide rods 3 so as to realize sliding relative to the bearing seat 21.

The upper end of the guide rod 3 is fixed with a mounting plate 4, the mounting plate 4 is fixed with a first hydraulic cylinder 5, the first hydraulic cylinder 5 is indirectly mounted on the frame 1 through the mounting plate 4, a piston rod of the first hydraulic cylinder 5 is fixed with a mounting seat 22, and a specific fixing structure can be welded or screwed and fixed through bolts. The piston rod of the first hydraulic cylinder 5 extends to drive the mounting seat 22 to approach the bearing seat 21.

In actual use, referring to fig. 1 and 2, the carrier assembly 2 is used for mounting a mold 6, the mold 6 includes an upper mold 61 and a lower mold 62, the upper mold 61 is mounted on the mounting base 22, the lower mold 62 is mounted on the carrier base 21, and both the upper mold 61 and the lower mold 62 have cavities. After the first hydraulic cylinder 5 drives the mounting seat 22 to approach the bearing seat 21 so that the upper die 61 and the lower die 62 are clamped, the upper die 61 and the lower die 62 are spliced to form the whole cavity for forming the workpiece. A liquid inlet groove 621 is provided in the side wall of the lower die 62, the opening of the liquid inlet groove 621 faces the direction of the mounting seat 22, and the liquid inlet groove 621 communicates with the cavity of the die 6.

The frame 1 is also provided with a second hydraulic cylinder 7, the cylinder body of the second hydraulic cylinder 7 is hinged with the frame 1, and the piston rod of the second hydraulic cylinder 7 is hinged with the bearing seat 21. Two propping blocks 8 are fixed on the end face of the bearing seat 21 far away from the mounting seat 22, the two propping blocks 8 are cylindrical blocks, the axes of the propping blocks 8 are parallel to the length direction of the guide rod 3, and the two propping blocks 8 are distributed at intervals along the direction of the hinge axis of the bearing seat 21. The frame 1 is fixed with two support portions 9, and support portions 9 are vertical cylinder, and the position of two support portions 9 and two support blocks 8 one-to-one correspond to each other and set up. When the piston rod of the second hydraulic cylinder 7 extends, the second hydraulic cylinder 7 drives the bearing seat 21 to turn over so that the abutting block 8 abuts against the upper end face of the corresponding abutting portion 9, and the upper die 61 is located right above the lower die 62, and at this time, the notch of the liquid inlet groove 621 faces upwards.

Referring to fig. 2 and 3, two limiting parts 10 are further fixed on the frame 1, the limiting parts 10 are in a vertical column structure, when a piston rod of the second hydraulic cylinder 7 is retracted, the second hydraulic cylinder 7 drives the bearing assembly 2 to turn over so that the bearing seat 21 abuts against the upper end face of the limiting column, the liquid inlet groove 621 is located right above the cavity, a notch of the liquid inlet groove 621 faces the horizontal direction, and molten metal in the liquid inlet groove 621 is guided into the cavity for forming.

Referring to fig. 2 and 4, in order to facilitate the workpiece to be removed from the cavity of the lower die 62 after being molded, a plurality of ejector pins 11 are disposed on the bearing seat 21, the length direction of each ejector pin 11 is parallel to the sliding direction of the mounting seat 22, each ejector pin 11 slides through the lower die 62, and the upper end of each ejector pin 11 is used for extending into the cavity of the lower die 62. The bearing seat 21 is also provided with a plate body 12, and the lower ends of the ejector pins 11 are fixed on the upper end surface of the plate body 12. The carrier 21 is further provided with a driving member 14, and the driving member 14 is used for driving the plate 142 body 12 to move so as to drive the ejector pins 11 to slide along the length direction of the ejector pins 11, so that the ejector pins 11 penetrate into the cavity of the lower die 62 to eject the workpiece towards the upper die 61.

The driving member 14 includes a driving cylinder 141, a driving plate 142, and a plurality of driving rods 143. The cylinder body of the driving oil cylinder 141 is mounted on the bearing seat 21, the driving plate 142 is fixedly mounted on the piston rod of the driving oil cylinder 141, each driving rod 143 is fixed on the end surface of the driving plate 142 far away from the driving oil cylinder 141, and the length direction of each driving rod 143 is parallel to the axis of the piston rod and the length direction of each thimble 11.

When the piston rod of the driving oil cylinder 141 extends, the piston rod drives the driving plate 142 to move, so that the driving rod 143 abuts against one end of the plate 12 far away from the ejector pin 11 to drive the plate 12 to move, and then the ejector pin 11 ejects the workpiece out of the cavity of the die 6.

In order to facilitate the reset of the ejector pins 11, the plate body 12 is also fixed with a plurality of reset rods 13, each reset rod 13 slides out of the upper part of the lower die 62, and the positions of the reset rods 13 are staggered with the positions of the die cavities. When the upper die 61 and the lower die 62 are clamped, the lower end surface of the upper die 61 abuts against the reset rod 13 so that the upper end surface of the reset rod 13 is flush with the upper end surface of the lower die 62, and at the moment, the upper end surface of the ejector pin 11 is flush with the inner wall of the cavity of the lower die 62.

The working principle of the embodiment is as follows:

the upper die 61 and the lower die 62 are installed in place, then the bearing assembly 2 is driven by the hydraulic cylinder II 7 to turn over to a state that the abutting block 8 abuts against the abutting part 9, the installation seat 22 is driven by the hydraulic cylinder I5 to move so that the upper die 61 and the lower die 62 are in a die-assembling state, and a sufficient amount of metal liquid (generally aluminum liquid) is poured into the liquid inlet groove 621. The second hydraulic cylinder 7 drives the bearing assembly 2 to turn over to a state of abutting against the abutting part 9, in the process, the liquid inlet groove 621 moves to the upper side of the cavity, the metal liquid in the liquid inlet groove 621 is guided into the cavity, after the metal liquid is solidified, the second hydraulic cylinder 7 drives the bearing assembly 2 to turn over to a state of abutting against the abutting part 9 by the abutting block 8, at the moment, the upper die 61 and the lower die 62 are distributed along the vertical direction, and then the first hydraulic cylinder 5 drives the mounting seat 22 to move upwards so that the upper die 61 and the lower die 62 are separated.

When the mounting seat 22 drives the upper die 61 to be far away from the lower die 62, the piston rod of the driving oil cylinder 141 stretches out to drive the driving plate 142 and the driving rod 143 to move upwards, the driving rod 143 pushes the plate body 12 upwards so that each thimble 11 moves upwards to eject a workpiece from the cavity of the lower die 62, and simultaneously the plate body 12 moves upwards so that the reset rod 13 protrudes out of the upper end face of the lower die 62. After an operator takes down a workpiece, the first hydraulic cylinder 5 drives the mounting seat 22 to move downwards, the upper die 61 abuts against the reset rod 13 in the moving process of the upper die so that the upper end face of the reset rod 13 is reset to be in a state of being flush with the upper end face of the lower die 62, at the moment, the upper end face of the ejector pin 11 is flush with the inner wall of the cavity of the lower die 62, at the moment, the upper die 61 and the lower die 62 are in a die clamping state, and then the next casting is carried out.

Embodiment two:

a gravity casting device, see fig. 5 and 6, differs from the first embodiment in that the structure of the driving member 14 is different. The driving piece 14 is an air cylinder 144, the cylinder body of the air cylinder 144 is arranged on the frame 1, and the piston rod of the air cylinder 144 extends out to push the plate body 12 to move so as to eject the thimble 11.

A piston cavity 15 is arranged in each abutting part 9, each piston cavity 15 is connected with a piston head 16 in a sliding way, and the sliding direction of the piston head 16 is vertical. The piston head 16 divides the corresponding piston cavity 15 into an upper cavity and a lower cavity, the cavity positioned below is communicated to the cylinder body of the cylinder 144 through a flexible plastic conduit to realize air supply, and when the piston cavity 15 positioned below is compressed, air is conveyed into the cylinder body of the cylinder 144 to push the piston rod of the cylinder 144 to extend. A dowel bar 17 is fixed at the upper end of the piston head 16, and the dowel bar 17 slides upwards to penetrate out of the upper end face of the abutting part 9.

When the hydraulic cylinder II 7 drives the bearing assembly 2 to overturn so that the abutting block 8 abuts against the abutting part 9, the abutting block 8 presses the upper end face of the dowel bar 17 to be in a state of being flush with the upper end face of the abutting part 9, at the moment, the piston cavities 15 located below are in a compressed state so that the pressure intensity rises, at the moment, the piston rods of the cylinders 144 have a stretching trend, when the hydraulic cylinder I5 drives the mounting seat 22 to move so that the upper die 61 is far away from the lower die 62, the ejector pins 11 rise under the action of the piston rods of the cylinders 144 to lift the workpiece, the workpiece is attached to the upper die 61 to move in the lifting process until the ejector pins 11 lift to the highest position, and the upper die 61 is separated from the workpiece. The workpiece is supported by the upper die 61 when being ejected, so that the condition that the workpiece collides with the ejector pins 11 due to inertial movement when being ejected by the ejector pins 11 is reduced.

Referring to fig. 5, the bearing assembly 2 is further provided with a pressure detection unit 18, the pressure detection unit 18 comprises a pressure sensor 181, a controller and a display 182, the pressure sensor 181 is mounted on the lower end face of the abutting block 8, the abutting block 8 abuts against the dowel 17 through the pressure sensor 181, the controller is electrically connected with the display 182 and the pressure sensor 181, and the display 182 is mounted on the bearing seat 21 or the frame 1 and used for displaying pressure values. In practice, a mounting groove is provided in the lower end face of the abutment block 8, the size of the mounting groove is larger than the cross-sectional area of the dowel bar 17, the pressure sensor 181 is mounted in the mounting groove and one end of the pressure sensor 181 facing the notch of the mounting groove is located in the mounting groove, and when the abutment block 8 abuts against the abutment portion 9, only the dowel bar 17 abuts against the pressure sensor 181.

After the abutting block 8 abuts against the abutting portion and the mold 6 is closed, the pressure of the pressure sensor 181 rises based on the condition that the piston chamber 15 located below is compressed and the piston rod is not extended, and the pressure detecting unit 18 can detect the abutting force between the dowel bar 17 and the abutting block 8. The compression amount of the piston rod of the driving cylinder 144 can be reversely pushed by the abutting force fed back by the pressure detection unit 18, so that the moving stroke of the reset rod 13 can be detected, the die clamping degree between the upper die 61 and the lower die 62 is detected, and when the die clamping is not in place due to molding waste between the upper die 61 and the lower die 62, the result can be fed back in time by the pressure detection unit 18, so that the die clamping of the upper die 61 and the lower die 62 is more ensured.

In practical use, in order to improve the detection accuracy of the pressure detection unit 18, oil is replenished into a chamber of the piston cavity 15 located below the corresponding piston head 16 and a chamber of the cylinder 144 communicated with the chamber, the gas in the space is reduced by filling the space with oil, the gas is only required to be 10% -30% more than the maximum compression, and the force change caused by the movement of the reset rod 13 is more obvious, so that the detection accuracy is better.

The foregoing are all preferred embodiments of the present application, and are not intended to limit the scope of the present application in any way, therefore: all equivalent changes in structure, shape and principle of this application should be covered in the protection scope of this application.

Claims

1. The gravity casting device comprises a frame (1), wherein the frame (1) is provided with a bearing assembly (2) for installing a die (6), the die (6) comprises an upper die (61) and a lower die (62), the upper die (61) and the lower die (62) are clamped to form a cavity, the outer wall of the lower die (62) is provided with a liquid inlet groove (621), and the liquid inlet groove (621) is communicated with the cavity; the method is characterized in that: the bearing assembly (2) comprises a first hydraulic cylinder (5) hinged to the bearing seat (21) of the frame (1), a second hydraulic cylinder (7) hinged to the mounting seat (22) of the bearing seat (21) and used for driving the bearing assembly (2) to turn over, so that the die (6) turns over to guide molten metal in the liquid inlet groove (621) into the die cavity, and the first hydraulic cylinder (7) is arranged on the frame (1) and is close to the bearing seat (21).

2. Gravity casting device according to claim 1, characterised in that: the machine frame (1) is provided with a limiting part (10), and the limiting part (10) is arranged so that the liquid inlet groove (621) is positioned right above the cavity when the liquid inlet groove is propped against the bearing assembly (2).

3. Gravity casting device according to claim 1, characterised in that: the frame (1) is provided with a propping part (9), the bearing seat (21) is provided with a propping block (8), and when the propping block (8) is propped against the propping part (9), the upper die (61) is positioned right above the lower die (62).

4. Gravity casting device according to claim 1, characterised in that: the bearing seat (21) is connected to the thimble (11) in a sliding mode, the sliding direction of the thimble (11) is parallel to the sliding direction of the mounting seat (22), the bearing seat (21) is further provided with a driving piece (14), and the driving piece (14) is used for driving the thimble (11) to penetrate into a cavity of the lower die (62) to eject a workpiece towards the direction of the upper die (61).

5. The gravity casting device according to claim 4, wherein: the ejector pins (11) are provided with a plurality of ejector pins; the novel ejector pin structure further comprises a plate body (12), each ejector pin (11) is fixed on the plate body (12), and the driving piece (14) drives the ejector pins (11) to move by driving the plate body (12) to move.

6. The gravity casting device according to claim 5, wherein: the driving piece (14) comprises a driving oil cylinder (141) arranged on the bearing seat (21), a driving plate (142) provided with a piston rod of the driving oil cylinder (141) and a plurality of driving rods (143) arranged on the driving plate (142), and each driving rod (143) is used for abutting against the plate body (12).

7. The gravity casting device according to claim 5, wherein: the plate body (12) is also provided with a reset rod (13), the reset rod (13) slides out of the upper side of the lower die (62), the position of the reset rod (13) is staggered with the position of the cavity, and when the upper die (61) and the lower die (62) are clamped, the upper die (61) is abutted to the reset rod (13) so that the ejector pins (11) are flush with the inner wall of the cavity of the lower die (62).

8. The gravity casting device according to claim 7, wherein: the driving piece (14) is an air cylinder (144), and a piston rod of the air cylinder (144) is used for pushing the plate body (12);

the frame (1) is provided with an abutting part (9), the bearing seat (21) is provided with an abutting block (8), and when the abutting block (8) abuts against the abutting part (9), the upper die (61) is positioned right above the lower die (62);

the piston is characterized in that a piston cavity (15) is arranged in the abutting part (9), a piston head (16) is connected in the piston cavity (15) in a sliding manner, a dowel bar (17) is fixed on the piston head (16), the dowel bar (17) slides upwards to penetrate through the abutting part (9), the piston cavity (15) is communicated with an inner cavity of the air cylinder (144), when the abutting part (9) is abutted against by the abutting block (8) so that the dowel bar (17) is pressed to be flush with the upper end face of the abutting part (9), the communicating area between the piston cavity (15) and the inner cavity of the air cylinder (144) becomes smaller, so that the pressure rises to be used for driving a piston rod of the air cylinder (144) to eject, and at the moment, when the upper die (61) is far away from the lower die (62), the ejector pin (11) drives a workpiece to be attached to the upper die (61) to be ejected under the action of the air cylinder (144).

9. The gravity casting device according to claim 8, wherein: the bearing assembly (2) is further provided with a pressure detection unit (18), the pressure detection unit (18) comprises a pressure sensor (181) arranged on the lower end face of the abutting block (8), a controller electrically connected with the pressure sensor (181) and a display (182) electrically connected with the controller, and the pressure detection unit (18) is used for detecting abutting force between the dowel bar (17) and the abutting block (8).