Planetary stirring mixer for sand mould additive manufacturing

Abstract

The utility model discloses a kind of planet stirring mixers for sand mould additive manufacturing, it is related to sand mould additive manufacturing technical field, including stirring cylinder, the top surface of the cylinder cover of stirring cylinder top is equipped with feed inlet, its top coaxial fixedly connected with sun gear, stirring cylinder inside below is provided with the transmission frame of horizontal arrangement and is fixed in stirring cylinder inner wall, two planet gears are symmetrically meshed and connected with the outside of sun gear, the top of two planet gears is coaxially fixed with a stirring shaft, the outside of each stirring shaft is uniformly provided with three layers of stirring blade along axial direction interval, and each layer blade is circumferentially symmetrically arranged.The utility model is through design branch type sand mixing blade structure, combine the uniform symmetrical distribution of three layers nine pieces of blade, can cover sand mould raw material stirring area in stirring cylinder comprehensively, break the mixed dead angle that traditional stirring blade is prone to appear, effectively solve the problem of insufficient mixing uniformity of existing sand mixing system.

Description

Technical Field

[0001] This utility model relates to the field of sand mold additive manufacturing technology, specifically to a planetary mixer for sand mold additive manufacturing. Background Technology

[0002] Automatic sand mixing is the foundation of sand-based additive manufacturing (3DP). Through its effective mixing of sand and gravel, it promotes the uniformity and stable flow of the sand and gravel during the manufacturing process, ensuring the consistency of each layer during additive manufacturing. It is the key to improving the quality of sand-based additive manufacturing. The sand mixing impeller is the actuator of the sand mixing system. By rotating the impeller, it drives the movement of the sand and gravel in the mixing tank, which can effectively prevent the deposition and stratification of materials in the sand and gravel, and achieve uniform mixing of the sand and gravel.

[0003] Existing mixing blade structures and stirring methods make it difficult to fully mix sand mold raw materials within the mixing tank, easily leading to mixing dead zones. This results in uneven mixing of sand mold raw materials in some areas, affecting the subsequent molding quality of the sand mold. Furthermore, large errors in sand layer thickness are also a problem plaguing the industry. Due to uneven sand mixing, it is difficult to maintain consistent thickness across sand mold layers during additive manufacturing. This not only affects the dimensional accuracy of the sand mold but may also lead to inconsistent strength during use.

[0004] For example, a multi-stage mixing device for sand, disclosed in CN222511917U, includes a mixing tank with a feed inlet at the top and a mixing component at the top. The mixing tank also has a discharge component inside. Although this patent improves the continuity of mixing and the controllability of discharge to some extent by setting up the mixing and discharge components, the core mixing component (mixing motor, rotating shaft and mixing blades) still has a relatively traditional and simple structure. It mainly relies on the blades on the same axis for rotation and mixing. This structure is prone to the problem of "mixing dead zones". The sand may still be insufficiently mixed at the edge, bottom and axial area of ​​the tank due to uneven flow field distribution, which will eventually lead to problems such as local unevenness of sand mold raw materials and large error in sand layer thickness.

[0005] Therefore, it is necessary to invent a planetary mixer for sand-based additive manufacturing to solve the above problems. Utility Model Content

[0006] The purpose of this invention is to provide a planetary mixer for sand-based additive manufacturing, in order to solve the problems of insufficient uniformity of sand mixing and large error in sand layer thickness in the above-mentioned technologies.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a planetary mixer for sand-based additive manufacturing, comprising a mixing cylinder, a feed inlet on the top surface of the cylinder cover, a servo motor mounted on one side of the bottom of the mixing cylinder, a drive shaft of the servo motor extending vertically upward, and a star gear coaxially fixedly connected to its top end, a horizontally arranged transmission frame fixed to the inner wall of the mixing cylinder at the bottom, two planetary gears symmetrically meshing on the outer side of the star gear, a gear ring sleeved on the outer side of the planetary gear, the outer teeth of the planetary gear meshing with the inner teeth of the gear ring, a mixing shaft coaxially fixedly connected to the top end of each of the two planetary gears, and three layers of mixing blades evenly spaced along the axial direction on the outer side of each mixing shaft, with each layer of blades circumferentially symmetrically arranged.

[0008] Preferably, the outer wall of the lower side of the mixing cylinder extends outward in a horizontal direction to form a discharge port with a discharge channel, and a hydraulic valve for controlling the discharge is connected in series above the discharge port.

[0009] Preferably, the sun gear is rotatably connected to the center hole of the transmission frame, and the planetary gears are all rotatably connected to the corresponding mounting holes of the transmission frame via rotating shafts.

[0010] Preferably, the top surface of the transmission frame protrudes upward to form an annular boss, and the top surface of the boss is covered with an isolation layer for isolating the raw materials and the transmission components. The isolation layer is made of wear-resistant composite material.

[0011] Preferably, the drive shaft at the top of the stellar gear continues upward through the isolation layer to the top, and three connecting rods are uniformly fixedly connected to the outer wall of the drive shaft in the circumferential direction. The ends of the three connecting rods are rotatably connected to rollers, and the top surface of the transmission frame is provided with an annular groove adapted to the rollers.

[0012] Preferably, the stirring shaft extends vertically upward through the isolation layer and into the cavity of the stirring tank. The isolation layer has a through hole adapted to the diameter of the shaft at the position where the stirring shaft passes through, and a sealing ring is embedded between the inner wall of the through hole and the outer wall of the stirring shaft.

[0013] Preferably, the three layers of stirring blades are arranged in a ring shape, with three blades in each layer, for a total of nine stirring blades. Each stirring blade extends outward from the outer wall of the stirring shaft in an orderly manner, and its overall distribution structure is adapted to the shape of branches branching outward from the trunk of a tree.

[0014] The technical effects and advantages provided by this utility model in the above technical solution are as follows: 1. This utility model uses a planetary gear transmission mechanism to drive the stirring shaft, enabling the material to simultaneously achieve a composite motion of revolution and rotation within the stirring cylinder. This results in highly efficient convection, shearing, and diffusion mixing, significantly improving the mixing uniformity of the sand mold material and effectively ensuring the molding consistency of sand mold additive manufacturing. 2. This utility model, through the design of a branched sand mixing blade structure, combined with the uniform and symmetrical distribution of three layers and nine blades, can fully cover the sand mold raw material mixing area in the mixing tank, breaking the mixing dead corners that are easy to occur in traditional mixing blades, and effectively solving the problem of insufficient mixing uniformity in existing sand mixing systems; at the same time, the branched structure can disperse the agglomeration force of sand mold raw materials, reduce the phenomenon of raw material agglomeration, thereby reducing the sand layer thickness error in the sand mold additive manufacturing process and improving product consistency.

[0015] 3. This utility model, by setting an isolation layer on the top surface of the transmission frame boss, and having the isolation layer cooperate with the sealing ring at the location where the stirring shaft passes through, forms a double-sealing protection structure, further enhancing the overall sealing performance of the equipment. This prevents fine sand particles from seeping into the transmission area from the gap between the stirring shaft and the isolation layer, reducing the frequency of equipment malfunctions and maintenance due to sealing problems, lowering the risk of production interruption, and providing a reliable guarantee for the continuous and stable operation of sand mold additive manufacturing. Attached Figure Description Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a three-dimensional structural diagram of the transmission frame and isolation layer of this utility model; Figure 3 This is a three-dimensional cross-sectional structural diagram of the isolation layer of this utility model; Figure 4 This is a three-dimensional structural diagram of the sun gear, planet gears and gear ring of this utility model; Figure 5 This is a top view schematic diagram of the sun gear, planet gears and gear ring of this utility model; Figure 6 This is a top view schematic diagram of the roller and groove structure of this utility model; Figure 7 This is a front view schematic diagram of the stirring shaft and stirring blades of this utility model.

[0016] Explanation of reference numerals in the attached figures: 1. Mixing cylinder; 2. Feed inlet; 3. Discharge outlet; 4. Hydraulic valve; 5. Servo motor; 6. Transmission frame; 7. Isolation layer; 8. Sun gear; 9. Planetary gear; 10. Gear ring; 11. Connecting rod; 12. Roller; 13. Wheel groove; 14. Mixing shaft; 15. Mixing blade. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0018] This utility model provides, for example Figure 1-7 The diagram shows a planetary mixer for sand-based additive manufacturing.

[0019] Combination Figure 1 The mixing cylinder 1 includes a feed inlet 2 on the top surface of the top cover of the mixing cylinder 1. The outer wall of the mixing cylinder 1 extends outward in a horizontal direction to form a discharge port 3 with a discharge channel. A hydraulic valve 4 for controlling the discharge is connected in series above the discharge port 3.

[0020] In this embodiment, the feed inlet 2 provides a convenient channel for chemical raw materials to enter the mixing cylinder 1, while the discharge port 3 is the channel for the material to be discharged from the mixing cylinder 1 after mixing. The hydraulic valve 4 can precisely control the opening and closing of the discharge and the timing. According to the requirements of the production process, the discharge port 3 can be opened or closed at the appropriate time to achieve quantitative discharge of materials and avoid material waste and leakage.

[0021] Combination Figure 4 and 5 A servo motor 5 is installed on one side of the bottom of the mixing tank 1. The drive shaft of the servo motor 5 extends vertically upward, and a stellar gear 8 is coaxially fixed to its top. A horizontally arranged transmission frame 6 is set inside the lower part of the mixing tank 1 and fixed to the inner wall of the mixing tank 1. The stellar gear 8 is rotatably connected to the center hole of the transmission frame 6. The planetary gears 9 are all rotatably connected to the corresponding mounting holes of the transmission frame 6 through rotating shafts. Two planetary gears 9 are symmetrically meshed on the outer side of the stellar gear 8. A gear ring 10 is sleeved on the outside of the planetary gear 9. The outer teeth of the planetary gear 9 are meshed with the inner teeth of the gear ring 10.

[0022] In this embodiment, the sun gear 8, planet gear 9, and gear ring 10 constitute the planet gear 9 transmission system. The sun gear 8 rotates under the drive of the servo motor 5 and transmits power to the planet gear 9 through meshing with it. The planet gear 9 revolves around the sun gear 8 while rotating on its own axis and meshes with the gear ring 10, further transmitting power to the stirring shaft 14. This achieves multi-stage transmission and amplification of power, providing sufficient torque for the stirring process and meeting the stirring requirements of chemical raw materials with different viscosities and densities.

[0023] Combination Figure 2 , 3The top surface of the transmission frame 6 protrudes upward to form an annular boss. The top surface of the boss is covered with an isolation layer 7 for isolating the raw materials and the transmission components. The isolation layer 7 is made of wear-resistant composite material. The drive shaft at the top of the stellar gear 8 continues upward through the isolation layer 7 to the top. Three connecting rods 11 are uniformly fixedly connected to the outer wall of the drive shaft along the circumference. The ends of the three connecting rods 11 are rotatably connected to rollers 12. The top surface of the transmission frame 6 is provided with an annular groove 13 that matches the rollers 12.

[0024] In this embodiment, the isolation layer 7 can effectively prevent the raw materials from corroding and wearing the transmission components, and extend the service life of the transmission components. The connecting rod 11, the roller 12, and the annular groove 13 form the support structure of the drive shaft. The roller 12 rolls in the annular groove 13, providing stable support for the drive shaft, reducing the vibration and shaking of the drive shaft during rotation, and improving the stability and reliability of the stirring system. At the same time, this support structure can also withstand certain axial and radial forces, ensuring the normal operation of the drive shaft under complex working conditions.

[0025] Combination Figure 7 The top of each of the two planetary gears 9 is coaxially fixed with a stirring shaft 14. Three layers of stirring blades 15 are evenly spaced along the axial direction on the outer side of each stirring shaft 14, and the blades in each layer are symmetrically arranged circumferentially. The stirring shaft 14 is vertically inserted through the isolation layer 7 and extends into the cavity of the stirring tank 1. The isolation layer 7 has a through hole with a diameter adapted to the shaft corresponding to the position where the stirring shaft 14 is inserted, and a sealing ring is embedded between the inner wall of the through hole and the outer wall of the stirring shaft 14. The three layers of stirring blades 15 are distributed in a ring shape, with three blades in each layer, for a total of nine stirring blades 15. Each stirring blade 15 extends outward from the outer wall of the stirring shaft 14 in an orderly manner, and its overall distribution structure is adapted to the shape of branches branching outward from the trunk of a tree.

[0026] In this embodiment, the stirring shaft 14 and the stirring blades 15 are the core components of the stirring system. The stirring shaft 14 transmits the power of the planetary gear 9 transmission system to the stirring blades 15. The unique distribution structure of the stirring blades 15, which is adapted to the shape of branches branching out from tree branches, enables the material to form multi-layered flow and mixing in the stirring tank 1. The three layers of stirring blades 15 are distributed in a ring shape. The three blades of each layer can stir the material from different directions, which increases the contact area between the material and the stirring blades 15, improves the stirring efficiency, and enables the material to be fully mixed to achieve a uniform stirring effect, thus meeting the requirements of chemical production for the mixing quality of materials.

[0027] Working principle of this utility model: Refer to the instruction manual appendix Figure 1-7When using this utility model, firstly, the prepared chemical raw materials are added into the mixing tank 1 through the feed port 2. At this time, the servo motor 5 is turned on. The drive shaft of the servo motor 5 drives the star gear 8 to rotate. The star gear 8 transmits power to the planet gear 9 through meshing with the planet gear 9. The planet gear 9 revolves around the star gear 8 while rotating on its own axis and meshes with the gear ring 10, further transmitting power to the mixing shaft 14. The mixing shaft 14 drives the mixing blade 15 to start rotating. When the stirring shaft 14 drives the stirring blades 15 to rotate at high speed to stir the material, it will generate a large action force and reaction force. These forces are transmitted to the drive shaft, which can easily cause the drive shaft to vibrate and shake. The rollers 12, which are rotatably connected to the ends of the three connecting rods 11, are embedded in the annular grooves 13 on the top surface of the isolation layer 7. The cooperation between the rollers 12 and the annular grooves 13 forms a stable support structure. During the rotation of the drive shaft, the rollers 12 roll along the annular grooves 13, which can effectively limit the radial displacement of the drive shaft, reduce the vibration amplitude of the drive shaft, and keep the drive shaft in a relatively stable rotational state. Once the material has achieved a uniform mixing effect, the servo motor 5 is stopped by the control system, causing the mixing blades 15 to stop rotating. The control device of the hydraulic valve 4 is operated to open the hydraulic valve 4, allowing the discharge port 3 to flow smoothly. The mixed material is then discharged from the mixing cylinder 1 through the discharge channel.

[0028] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0029] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A planetary mixer for sand-mold additive manufacturing, comprising a mixing cylinder (1), characterized in that: The top surface of the top cover of the mixing cylinder (1) is provided with a feed port (2). A servo motor (5) is installed on one side of the bottom of the mixing cylinder (1). The drive shaft of the servo motor (5) extends vertically upward, and a star gear (8) is coaxially fixedly connected to its top end. A horizontally arranged transmission frame (6) is provided at the bottom of the mixing cylinder (1) and fixed to the inner wall of the mixing cylinder (1). Two planetary gears (9) are symmetrically meshed on the outer side of the star gear (8). A gear ring (10) is sleeved on the outer side of the planetary gear (9). The outer teeth of the planetary gear (9) mesh with the inner teeth of the gear ring (10). A stirring shaft (14) is coaxially fixedly connected to the top end of each of the two planetary gears (9). Three layers of stirring blades (15) are evenly arranged on the outer side of each stirring shaft (14) along the axial direction, and each layer of blades is symmetrically arranged circumferentially.

2. A planetary mixing machine for sand mould additive manufacturing according to claim 1, characterized in that: The outer wall of the mixing cylinder (1) extends outward in the horizontal direction to form a discharge port (3) with a discharge channel. A hydraulic valve (4) for controlling the discharge is connected in series above the discharge port (3).

3. A planetary mixing machine for sand mould additive manufacturing according to claim 1, characterized in that: The stellar gear (8) is rotatably connected to the center hole of the transmission frame (6), and the planetary gears (9) are all rotatably connected to the corresponding mounting holes of the transmission frame (6) via rotating shafts.

4. A planetary mixing machine for sand mould additive manufacturing according to claim 3, characterized in that: The top surface of the transmission frame (6) protrudes upward to form an annular boss, and the top surface of the boss is covered with an isolation layer (7) for isolating the raw materials and the transmission components. The isolation layer (7) is made of wear-resistant composite material.

5. A planetary mixing machine for sand mould additive manufacturing according to claim 1, characterized in that: The drive shaft at the top of the stellar gear (8) continues upward through the isolation layer (7) to the top, and three connecting rods (11) are uniformly fixedly connected to the outer wall of the drive shaft in the circumferential direction. The ends of the three connecting rods (11) are rotatably connected to rollers (12). The top surface of the transmission frame (6) is provided with an annular groove (13) that is adapted to the rollers (12).

6. A planetary mixing machine for sand mould additive manufacturing according to claim 1, characterized in that: The stirring shaft (14) is vertically extended through the isolation layer (7) and into the cavity of the stirring tank (1). The isolation layer (7) has a through hole with a diameter adapted to the shaft at the position where the stirring shaft (14) passes through, and a sealing ring is embedded between the inner wall of the through hole and the outer wall of the stirring shaft (14).

7. A planetary mixing machine for sand mould additive manufacturing according to claim 1, characterized in that: The three layers of stirring blades (15) are arranged in a ring shape. Each layer has three blades, and a total of nine stirring blades (15) are arranged. Each stirring blade (15) extends outward from the outer wall of the stirring shaft (14) in an orderly manner. Its overall distribution structure is adapted to the shape of branches branching outward from the trunk.

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