Precasting pin suitable for long and thin oil duct of die casting

Abstract

The utility model relates to a type pin, in particular to a pre-casting type pin suitable for a long and thin oil duct of a die casting, and solves the technical problems that an existing type pin is long and thin on the whole, is prone to deformation or breakage during use, and is prone to shrinkage porosity defects, and the diameter of an avoiding section matched with a large hole of a type pin hole is increased compared with that of a type pin head section. The first water channel, the second water channel and the third water channel are formed in the mold pin head section, the avoiding section and the blocking section correspondingly and communicate with one another to form the cooling water channel, and the cooling water channel is connected with a point cooling machine. And the cooling speed is more uniform when the metal material for manufacturing the gearbox shell is solidified, and the shrinkage porosity defect is avoided.

Description

Technical Field

[0001] This utility model relates to a molding pin, specifically a precast molding pin suitable for slender oil passages in die-cast parts. Background Technology

[0002] In the production of transmission housings, casting is widely used. However, due to the complex structure and dense oil passages of transmission housings, die casting is generally employed for shaping. Die casting is a common metal forming process, primarily used to produce complex-shaped, high-precision metal products. This process involves injecting molten metal into a metal mold under high pressure, allowing it to cool and solidify within the mold to obtain the desired product. The mold typically consists of two parts: a moving mold and a fixed mold. When combined, these form a sealed cavity for injecting molten metal.

[0003] In die castings, die pins are used to form features such as holes and cavities. The forming of oil passages in transmission housings requires the use of die pins. In some models of transmission housings, the oil passage area is thick. During the solidification process of the metal material, uneven cooling rate can easily lead to shrinkage defects, resulting in air leakage in the casting and greatly reducing the air tightness qualification rate.

[0004] Chinese invention patent CN111283167B discloses a rapid cooling die-casting mold core-pulling device. The device includes a base, a wedge-clamping unit, and a pre-pulling unit. In the wedge-clamping unit, a wedge-clamping slider seat is mounted on the right die-casting module, the fixed end of an inclined guide post is mounted on the wedge-clamping slider seat, and the insertion end extends beyond the end face of the wedge-clamping slider seat. A wedge-clamping block is mounted on the wedge-clamping slider seat. In the pre-pulling unit, pre-pulling pressure plates are mounted on the groove walls on both sides of the sliding mounting groove of the base, and a pre-pulling slider is mounted between the two pre-pulling pressure plates. The side of the pre-pulling slider has an inclined hole for insertion into the inclined guide post, and a cooling channel is provided inside. One end of a die pin sleeve is fixedly mounted on the base, and the other end is mounted on the left die-casting module. The pre-pulling pin includes a die pin tube and a cooling tube. The cooling tube is located inside the die pin tube, with one end connected to the cooling channel and the other end connected to the inner cavity of the die pin tube. This type of cold-pressed pin uses internal cooling pipes to make the cooling rate more uniform when the metal material solidifies, thus avoiding shrinkage defects.

[0005] However, the aforementioned slightly cold-pin structure still adopts the traditional external structure, and its structure is as follows: Figure 1As shown, the structure includes a forming section 1, a mating section 2, and a blocking section 4 connected coaxially in sequence. The forming section 1 and the mating section 2 are integrally formed and have the same diameter. The forming section 1 mates with a pre-cast hole in the gearbox housing, while the mating section 2 mates with a pin hole on the mold. The blocking section 4 mates with a limiting groove on the mold to prevent the entire pin from sliding into the pin hole. If the pre-cast oil channel diameter is large enough and the length is short, this traditional structure has no major problems in use. However, some gearbox housings now have pre-cast oil channels with a diameter of approximately 5mm and a long length. If the pin hole on the mold has the same diameter as the pre-cast oil channel, the entire pin still uses… Figure 1 The structure shown results in a long and slender pin design, with the total length of the mating section 2 and the forming section 1 being at least 200mm. This makes it prone to deformation or breakage during use. Since die-casting molds typically weigh tens of tons, if the pin breaks and needs to be replaced, disassembly and repair are time-consuming and labor-intensive, affecting production. Utility Model Content

[0006] The purpose of this invention is to solve the technical problems of existing die pins being slender and prone to deformation or breakage during use, as well as shrinkage defects, and to provide a precast die pin suitable for slender oil channels in die castings.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A precast pin suitable for use in slender oil channels of die-cast parts, characterized by:

[0009] It includes a forming section, a mating section, a clearance section, and a blocking section that are connected coaxially in sequence.

[0010] The forming section is used for forming the precast oil passage of the gearbox housing; the mating section and the clearance section are used to mate with the pin hole of the mold; the blocking section is used to mate with the limiting groove of the mold; the inner end face of the blocking section is used to abut against the bottom of the limiting groove; the pin hole is a stepped hole; the clearance section mates with the large hole section of the stepped hole; and the mating section mates with the small hole section of the stepped hole.

[0011] The forming section and the mating section have the same diameter and are integrally formed to form a pin head section;

[0012] The pin head section, the clearance section, and the blocking section are respectively provided with a first water channel, a second water channel, and a third water channel. The second water channel and the third water channel respectively pass through the clearance section and the blocking section. The length of the first water channel is less than the length of the pin head section. The first water channel, the second water channel, and the third water channel are connected to form a cooling water channel.

[0013] The cooling water channel is used to connect to the point chiller;

[0014] The diameter of the clearance section is larger than that of the pin head section. Let the diameter of the clearance section be A and the diameter of the pin head section be B. Then, the following condition must be met: 1mm≤AB≤2mm.

[0015] If the diameters of the first, second, and third water channels are all C, then the following condition is satisfied: 2.5mm ≤ C ≤ 3.5mm.

[0016] Furthermore, the diameter B of the pin head section is 5mm, and the diameter A of the clearance section is 6-7mm.

[0017] Furthermore, the diameter A of the avoidance section is 7 mm.

[0018] Furthermore, the cooling water channel is connected to the spot cooler via a spot cooling pipe, which is located inside the cooling water channel.

[0019] Furthermore, the diameter C of the first waterway, the second waterway, and the third waterway is 3mm.

[0020] Furthermore, the pin head section, the avoidance section, and the blocking section are all integrated and made of H13 steel.

[0021] Furthermore, the connection between the pin head section and the clearance section adopts a chamfered transition.

[0022] Compared with the prior art, the beneficial effects of this utility model are:

[0023] (1) The present invention provides a precast pin suitable for slender oil channels in die castings. By making the clearance section match the large hole section of the pin hole, and increasing the diameter of the clearance section compared with the pin head section, the entire pin is prevented from having a slender structure, thus improving the strength of the entire pin. Furthermore, a first water channel, a second water channel, and a third water channel are respectively opened in the pin head section, the clearance section, and the blocking section. The three are connected to form a cooling water channel, and the cooling water channel is connected to the spot cooler, so that the metal material used to make the gearbox housing cools more evenly during solidification, thus avoiding shrinkage defects. The diameter of the clearance section is 1mm to 2mm larger than that of the pin head section. This way, when the pin hole that mates with the clearance section is enlarged, it will not affect the surrounding hole system. It can also increase the strength of the pin. Furthermore, it does not require changing the size of the pre-cast oil channel. Only the pin hole and pin structure on the mold need to be adjusted, resulting in low processing costs. The diameter C of the first, second, and third water channels meets the condition 2.5mm≤C≤3.5mm. This ensures the cooling water volume without excessively affecting the strength of the pin.

[0024] (2) The diameter B of the precast pin head section of the precast pin provided by this utility model is 5mm and the diameter A of the clearance section is 7mm. The diameter of the clearance section is increased as much as possible within the maximum allowable range of the design to ensure the structural strength of the pin.

[0025] (3) The present invention provides a precast pin with a pin head section, a clearance section and a blocking section that are integrated into one piece and are all made of H13 steel. It has good thermal crack resistance and wear resistance, and high hardness, which can further enhance the strength of the pin structure. Attached Figure Description

[0026] Figure 1 This is a structural diagram of an existing pin type;

[0027] Figure 2 This is a schematic diagram of the structure of an embodiment of the precast pin suitable for slender oil channels in die castings according to the present invention;

[0028] Figure 3 This is a schematic diagram of the present invention in use (the cooling unit is not shown);

[0029] Figure 4 for Figure 3 A magnified view of part A.

[0030] The annotations in the attached figures are explained as follows:

[0031] 1-Forming section, 2-Matching section, 3-Avoidance section, 4-Blocking section, 5-Point cooling pipe. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0033] Reference Figures 2-4 As shown, a precast pin of this utility model, suitable for slender oil passages in die-cast parts, includes a forming section 1, a mating section 2, a clearance section 3, and a blocking section 4 connected coaxially in sequence. Figure 3 and Figure 4 As shown, forming section 1 is used for pre-cast oil passage forming of gearbox housing, while mating section 2 and clearance section 3 are used to mate with pin holes on mold to achieve pin positioning, and blocking section 4 is used to mate with limiting groove on mold to prevent the entire pin from falling into pin hole, so the inner end face of blocking section 4 abuts against the bottom of limiting groove.

[0034] The forming section 1 and the mating section 2 have the same diameter and are integrally formed to form the pin head section. The pin head section, the clearance section 3, and the blocking end 4 are integrally formed. The connection between the pin head section and the clearance section 3 is chamfered to prevent scratching the inner wall of the pin hole when it is inserted into the pin hole. All of them are made of H13 steel, which has good resistance to thermal cracking, mold resistance, and hardness, and can further increase the structural strength of the pin.

[0035] In this embodiment, the pin hole on the mold was modified by machining it into a stepped hole. The larger section of the stepped hole mates with the clearance section 3, while the smaller section mates with the mating section 2. The forming section 1 and the mating section 2 have the same diameter and are integrally formed to create the pin head section. The diameter of the clearance section 3 is larger than that of the pin head section, which prevents the entire pin from being elongated. The diameter of the clearance section 3 is defined as A, and the diameter of the pin head section is defined as B, satisfying 1mm ≤ AB ≤ 2mm. This relationship strengthens the structural strength of the pin without affecting other surrounding holes. In this embodiment, the diameter B of the pin head section is 5mm, and the diameter A of the clearance section is between 6-7mm. To maximize the structural strength of the pin within the design limits, the diameter A of the clearance section 3 is 7mm in this embodiment.

[0036] To prevent shrinkage defects in the precast oil channels, a first water channel, a second water channel, and a third water channel are respectively formed inside the pin head section, the clearance section 3, and the blocking section 4. The second and third water channels respectively penetrate the clearance section 3 and the blocking section 4, while the length of the first water channel is less than the length of the pin head section, meaning the first water channel does not penetrate the pin head section. The first, second, and third water channels are connected to form a cooling water channel. The diameters of the first, second, and third water channels are all C, and they satisfy: 2.5mm ≤ C ≤ 3.5mm. Within this range, the cooling water volume can be guaranteed without excessively affecting the structural strength of the pin. In this embodiment, the diameter C of the first, second, and third water channels is 3mm.

[0037] The cooling water channel is connected to the spot cooler through spot cooling pipe 5. Spot cooling pipe 5 is located inside the cooling water channel to continuously supply cooling water to the cooling water channel, thus ensuring the consistency of the temperature gradient of the entire mold and making the cooling rate of the metal material uniform during the solidification process.

[0038] When using it, first insert the mold pin into the mold pin hole, then close the mold, and then pour the molten aluminum into the inner cavity of the mold. At this time, turn on the cooling machine and pass cooling water into the cooling water channel through the cooling pipe 5 for 45 seconds. Then blow air into the mold pin hole for 60 seconds to remove the heat of the molten aluminum and make the molten aluminum solidify in sequence to prevent shrinkage and porosity that could cause air leakage in the gearbox housing casting. After the gearbox housing is formed, open the mold and take it out.

[0039] If a traditional pin structure is used, deformation or breakage will occur after producing about 500 gearbox housing castings. However, with the pin structure in this embodiment, at least 2,000 pieces can be produced, and the first-pass airtightness qualification rate of the gearbox housing castings is increased from the original 26% to 90%. It can be seen that the pin structure in this embodiment has greatly enhanced strength.

[0040] The embodiments described above are merely descriptions of specific implementations of this utility model and are not intended to limit the scope of this utility model. Various modifications and improvements made to the technical solutions of this utility model by those skilled in the art without departing from the spirit of this utility model should fall within the protection scope defined by the claims of this utility model.

Claims

1.A pre-mold pin suitable for an elongated oil passage of a die casting, characterized in that: it comprises a forming section (1), a matching section (2), an avoiding section (3) and a blocking section (4) connected coaxially in sequence; the forming section (1) is used for forming a pre-mold oil passage of a gearbox housing, the matching section (2) and the avoiding section (3) are used for matching with a pin hole of a mold, the blocking section (4) is used for matching with a limiting groove of the mold, and an inner end surface of the blocking section (4) is used for abutting against a groove bottom of the limiting groove; the pin hole is a stepped hole, the avoiding section (3) matches with a large hole section of the stepped hole, and the matching section (2) matches with a small hole section of the stepped hole; the forming section (1) and the matching section (2) have the same diameter and are integrally arranged, forming a pin head section; inner parts of the pin head section, the avoiding section (3) and the blocking section (4) are respectively provided with a first water channel, a second water channel and a third water channel, the second water channel and the third water channel respectively pass through the avoiding section (3) and the blocking section (4), the first water channel has a length smaller than that of the pin head section, and the first water channel, the second water channel and the third water channel are communicated to form a cooling water channel; the cooling water channel is used for being communicated with a spot cooling machine; the diameter of the avoiding section (3) is greater than that of the pin head section, the diameter of the avoiding section (3) is defined as A, and the diameter of the pin head section is defined as B, and 1mm≤A-B≤2mm is satisfied; the diameters of the first water channel, the second water channel and the third water channel are all C, and 2.5mm≤C≤3.5mm is satisfied. 2.The pre-mold pin suitable for the elongated oil passage of the die casting according to claim 1, characterized in that: the diameter B of the pin head section is 5mm, and the diameter A of the avoiding section (3) is 6-7mm. 3.The pre-mold pin suitable for the elongated oil passage of the die casting according to claim 2, characterized in that: the diameter A of the avoiding section (3) is 7mm. 4.The pre-mold pin suitable for the elongated oil passage of the die casting according to claim 3, characterized in that: the cooling water channel is communicated with the spot cooling machine through a spot cooling pipe (5), and the spot cooling pipe (5) is located in the cooling water channel. 5.The pre-mold pin suitable for the elongated oil passage of the die casting according to claim 2, characterized in that: the diameter C of the first water channel, the second water channel and the third water channel is 3mm. 6.The pre-mold pin suitable for the elongated oil passage of the die casting according to claim 1, characterized in that: the pin head section, the avoiding section (3) and the blocking section (4) are integrally arranged and are all made of H13 steel. 7.The pre-mold pin suitable for the elongated oil passage of the die casting according to claim 6, characterized in that: a connecting part of the pin head section and the avoiding section (3) adopts a chamfer transition. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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