Pull rod production process

Abstract

The invention belongs to the technical field of casting production and processing and discloses a pull rod production process which comprises the following steps: S1, sand mold casting: casting cast iron molten iron to produce a pull rod casting semi-finished product; the pull rod casting semi-finished product further comprises a cylindrical process block, and the cylindrical process block is integrally connected to the cantilever end of the supporting lug plate and is coaxial with the pull rod body. The cylindrical process block is connected with the end faces of the two supporting lug plates, and the outer diameter of the cylindrical process block is smaller than that of the pull rod body. S2, heat treatment is conducted, specifically, annealing treatment is conducted on the pull rod casting semi-finished product; s3, machining is conducted, specifically, the outer circle of the pull rod body is turned, a front pin shaft hole and a rear pin shaft hole are reamed, and the cylindrical process block is removed; and S4, surface treatment, and paint spraying or plastic spraying treatment. The pull rod production process can reduce the heat treatment deformation of the pull rod casting semi-finished product, improve the yield and improve the production benefit.

Description

Technical Field

[0001] The invention relates to the technical field of casting production and processing, and in particular to a pull rod production process. Background Art

[0002] like Figure 1 and Figure 2 As shown, the tie rod parts are commonly used mechanical accessories for rail transit train trucks and large highway trucks. They are used to support the transition box plate. They are generally formed by casting blanks. Their main function is to transmit axial tension and thrust after connecting other parts at both ends through pins. Specific structure: The tie rod includes a coaxially arranged tie rod body 1, a single-hole joint 2 and a lug plate 4. The front end of the tie rod body 1 is integrally connected to the single-hole joint 2, and a front pin hole 3 is centrally opened on the single-hole joint 2. The rear end of the tie rod body 1 is integrally connected to two symmetrically arranged lug plates 4, and a rear pin hole 5 is opened at the end of the lug plate 4. Generally speaking, the axis center lines of the front pin hole 3 and the rear pin hole 5 are arranged in parallel. An ear slot 6 for inserting the arm plate is reserved between the two lug plates 4. In order to enable the tie rod body 1 to obtain a larger working swing angle, the length of the ear slot 6 is also relatively large, often greater than the diameter of the two tie rod bodies 1.

[0003] After the tie rod casting blank is taken out of the sand box and the sand is removed and the gate burrs are removed, it is often necessary to anneal it to remove the casting stress. However, due to the influence of casting residual stress, such as Figure 2 As shown, the tie rod casting blank is inevitably deformed during the annealing heat treatment process, and in most cases, the cantilever rear end of the two ear plates 4 is deformed inwardly. Such severe deformation will cause the arm plates to be unable to pass through the ear slots 6, causing part of the casting blank to be scrapped, affecting production efficiency.

[0004] In order to overcome the above problems, a pull rod production process is needed. Summary of the invention

[0005] The purpose of the present invention is to provide a tie rod production process, which can reduce the heat treatment deformation of tie rod casting semi-finished products, increase the yield rate and improve production efficiency.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides a pull rod production process, comprising the following steps: S1. Sand casting, using cast iron molten iron to cast and produce a semi-finished tie rod casting; wherein the semi-finished tie rod casting also includes a cylindrical process block, which is integrally connected to the cantilever end of the lug plate and is coaxially arranged with the tie rod body; the cylindrical process block is connected to the end faces of both lug plates, and the outer diameter of the cylindrical process block is smaller than the outer diameter of the tie rod body; S2, heat treatment, annealing the semi-finished tie rod casting; S3, machining, turning the outer circle of the pull rod body, expanding the front pin shaft hole and the rear pin shaft hole, and removing the cylindrical process block; S4, surface treatment, painting or plastic spraying.

[0007] Furthermore, the tie rod casting semi-finished product also includes a thinning platform, which is formed on a side of the ear plate away from the ear groove; the length of the thinning platform is aligned with the ear groove.

[0008] Furthermore, the bottom surface of the thinning table is perpendicular to the axis of the rear pin shaft hole, and the distance between the two thinning tables is greater than the outer diameter of the cylindrical process block.

[0009] Furthermore, a top hole is coaxially arranged on the outer end surface of the cylindrical process block.

[0010] Furthermore, an anti-deformation bowl mouth is coaxially arranged on the outer end surface of the cylindrical process block, and the top hole is arranged on the bottom surface of the anti-deformation bowl mouth.

[0011] Furthermore, when turning the outer circle of the pull rod body in step S3, a turning tool is used to clamp the single-hole joint.

[0012] Furthermore, the turning tool is in the shape of a short cylinder, and its outer wall is in contact with the claws of the three-jaw chuck of the lathe; a mounting groove is centrally opened on the end face of the turning tool facing the single-hole joint; the cross-section of the mounting groove is in the shape of an isosceles triangle, and the two inclined waist surfaces of the mounting groove are respectively abutted against the outer arc wall of the single-hole joint; the width of the mounting groove is adapted to the thickness of the single-hole joint.

[0013] Furthermore, when turning the outer circle of the tie rod body in step S3, the tie rod casting semi-finished product uses a chuck to clamp the cylindrical process block at the other end or uses a lathe center to abut against the center hole.

[0014] Furthermore, in step S3, when removing the cylindrical process block, an angle grinder is installed with a cutting blade to cut off the cylindrical process block from the end surface of the ear plate.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are: The tie rod production process of the present invention, by adding a cylindrical process block to the cantilever end of the lug plate, is equivalent to setting an auxiliary support at the cantilever ends of the two lug plates. During the annealing process, the cantilever ends of the lug plates are blocked by the cylindrical process block during the residual stress release process and will not close inward, so that the distance between the two lug plates will not be reduced due to deformation. The tie rod production process of the present invention can reduce the heat treatment deformation of the tie rod casting semi-finished product, improve the yield rate, and improve the production efficiency.

[0016] In addition, by forming a concave thinning platform on the side of the lug plate away from the lug groove, the two sides of the connection between the root of the lug plate and the main body of the tie rod are roughly the same, reducing the left and right swing deformation of the lug plate during the heat treatment process. At the same time, the thinning platform reduces the material consumption without reducing the strength of the lug plate, and the setting of the thinning platform is also convenient for loading and clamping the rear pin shaft hole expansion. By adding a top hole on the outer end surface of the cylindrical process block, the lathe top can be used for auxiliary support when clamping the semi-finished tie rod casting. By setting an anti-deformation bowl mouth on the outer end surface of the cylindrical process block, the outer wall of the cylindrical process block is thin-walled. During casting, the thin wall of the bowl mouth cools quickly and is subjected to tensile stress; the inner side of the cylindrical process block cools slowly and is subjected to compressive stress. During the annealing process, the stress is relaxed, the thin wall of the bowl mouth shrinks, and a closed mouth is formed, which drives the inner side of the cylindrical process block to have a tendency to expand outward, which can balance the closing trend of the lug plate. That is, the anti-deformation bowl mouth can not only reduce the material consumption of the cylindrical process block, but also play a role in reverse anti-deformation. By adding a turning tool to clamp the single-hole joint, all the outer cylindrical parts of the pull rod body and the lug plate are freed, so that the entire outer cylindrical surface can be completed by machining at one time. By opening a clamping groove in the center of the outer end face of the turning tool, the clamping groove is adapted to the outer arc wall of the single-hole joint, and it can also prevent circumferential rotation under the premise of automatic centering. By using the turning tool and the lathe center, the outer cylindrical part that needs to be processed is completely freed, which reduces the difficulty of turning and can significantly improve the turning dimensional accuracy. The addition of the annular stop makes it easy to quickly position and load the turning tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings.

[0018] Figure 1 It is a three-dimensional schematic diagram of an existing tie rod casting blank; Figure 2 It is a schematic diagram of the main structure of the existing tie rod casting blank; Figure 3 This is a schematic diagram of the three-dimensional structure of a semi-finished tie rod casting according to Example 1 of the present invention; Figure 4 This is a schematic diagram of the front view of the semi-finished tie rod casting of Example 1 of the present invention; Figure 5 This is a schematic diagram of the three-dimensional structure of a semi-finished tie rod casting according to Example 2 of the present invention; Figure 6 This is a schematic diagram of the front cross-sectional structure of the bottom of a semi-finished tie rod casting according to Example 2 of the present invention; Figure 7 This is a schematic diagram of the three-dimensional structure of a turning tool according to Embodiment 3 of the present invention; Figure 8 This is a schematic diagram of the turning and clamping state of Example 3 of the present invention.

[0019] Explanation of the reference numerals: 1. Pull rod body; 2. Single-hole joint; 3. Front pin shaft hole; 4. Support ear plate; 5. Rear pin shaft hole; 6. Ear groove; 7. Thinning table; 8. Cylindrical process block; 9. Anti-deformation bowl mouth; 10. Center hole; 11. Turning tool; 111. Mounting slot; 12. Lathe center. DETAILED DESCRIPTION

[0020] The core of the present invention is to provide a tie rod production process, which can reduce the heat treatment deformation of tie rod casting semi-finished products, increase the yield rate, and improve production efficiency.

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] With reference to the accompanying drawings, Figure 1 It is a three-dimensional schematic diagram of an existing tie rod part; Figure 2 It is a schematic diagram of the main structure of the existing tie rod parts; Figure 3 This is a schematic diagram of the three-dimensional structure of a semi-finished tie rod casting according to Example 1 of the present invention; Figure 4 This is a schematic diagram of the front view of the semi-finished tie rod casting of Example 1 of the present invention; Figure 5 This is a schematic diagram of the three-dimensional structure of a semi-finished tie rod casting according to Example 2 of the present invention; Figure 6 This is a schematic diagram of the front cross-sectional structure of the bottom of a semi-finished tie rod casting according to Example 2 of the present invention; Figure 7 This is a schematic diagram of the three-dimensional structure of a turning tool according to Embodiment 3 of the present invention; Figure 8 This is a schematic diagram of the turning and clamping state of Example 3 of the present invention. Example 1

[0024] like Figure 3 and Figure 4 As shown, the pull rod production process of the present invention comprises the following steps: S1, sand casting, using cast iron molten iron to cast and produce a tie rod casting semi-finished product. Among them, the tie rod casting semi-finished product is mostly consistent with the existing tie rod casting blank, including a tie rod body 1, a single-hole joint 2 and a lug plate 4, and a front pin hole 5 is provided on the single-hole joint 2, and a rear pin hole 5 is provided on the lug plate 4. The important innovation of the process of the present invention: the tie rod casting semi-finished product also includes a cylindrical process block 8, which is integrally connected to the cantilever end of the lug plate 4 and is coaxially arranged with the tie rod body 1. The cylindrical process block 8 is connected to the end faces of the two lug plates 4, and the outer diameter of the cylindrical process block 8 is smaller than the outer diameter of the tie rod body 1.

[0025] S2. Heat treatment: anneal the semi-finished tie rod casting. When using gray cast iron, the annealing temperature is controlled at 550-580℃, kept warm for 3-4 hours, and then slowly cooled. It can eliminate internal stress, reduce surface hardness, and facilitate later processing.

[0026] S3, machining, turning the outer circle of the pull rod body 1 to meet the size requirements. Use a radial drill to expand the front pin shaft hole 3 and the rear pin shaft hole 5 so that the pin shaft can be smoothly inserted. Remove the cylindrical process block 8.

[0027] S4, surface treatment, painting or plastic spraying. Warehouse after inspection.

[0028] By adding a cylindrical process block 8 to the cantilever end of the lug plate 4, it is equivalent to setting an auxiliary support at the cantilever ends of the two lug plates 4. During the annealing process, the cantilever ends of the lug plates 4 are blocked by the cylindrical process block 8 during the residual stress release process and will not close inward, so that the distance between the two lug plates 4 will not be reduced due to deformation. The tie rod production process of the present invention can reduce the heat treatment deformation of the tie rod casting semi-finished product, improve the yield rate, and improve the production efficiency.

[0029] Specifically, in step S3, when removing the cylindrical process block 8, an angle grinder is used to install a cutting blade to cut off the cylindrical process block 8 from the end surface of the ear plate 4. When using the angle grinder, it is necessary to avoid damaging the ear plate 4 by the angle grinder.

[0030] Obviously, when removing the cylindrical process block 8, a cutting knife can also be used on a lathe to cut off the cylindrical process block 8 from the end surface of the lug plate 4. The advantage of this treatment is that the end surface of the lug plate 4 can also be processed at the same time, but the disadvantage is that the labor cost is increased. Similar simple replacement methods all fall within the scope of protection of the present invention.

[0031] In a specific implementation of this embodiment, Figure 3 and Figure 4 As shown, the tie rod casting semi-finished product further includes a thinning platform 7, which is formed on the side of the ear plate 4 away from the ear groove 6 in a concave molding manner. The length of the thinning platform 7 is aligned with the ear groove 6.

[0032] Specifically, if Figure 3 and Figure 4 As shown, the bottom surface of the thinning platform 7 is perpendicular to the axis of the rear pin shaft hole 5, and the two thinning platforms 7 are symmetrically formed on the two lug plates 4. The distance between the two thinning platforms 7 is greater than the outer diameter of the cylindrical process block 8.

[0033] By forming a concave thinning platform 7 on the side of the ear plate 4 away from the ear groove 6, the two sides of the connection between the root of the ear plate 4 and the pull rod body 1 are roughly the same, reducing the left and right swing deformation of the ear plate 4 during the heat treatment process. At the same time, the thinning platform 7 reduces the amount of material without almost reducing the strength of the ear plate 4. The setting of the thinning platform 7 also facilitates the expansion of the rear pin shaft hole 5 when installing the card. Example 2

[0034] In the above embodiment 1, the cylindrical process block 8 can be clamped by a chuck in the later process of turning the outer circle of the pull rod body 1, avoiding the direct clamping of the cantilever end of the ear plate 4. However, the tail box of a general lathe is provided with a lathe center 12 instead of a chuck tooling, so it needs to be improved.

[0035] In a specific implementation of this embodiment, Figure 5 and Figure 6 As shown, a top hole 10 is coaxially arranged on the outer end surface of the cylindrical process block 8. The angle of the top hole 10 is 60 degrees.

[0036] By adding a center hole 10 on the outer end surface of the cylindrical process block 8, a lathe center 12 can be used for auxiliary support when clamping the semi-finished pull rod casting.

[0037] Specifically, an anti-deformation bowl mouth 9 is coaxially arranged on the outer end surface of the cylindrical process block 8 , and the top hole 10 is arranged on the bottom surface of the anti-deformation bowl mouth 9 .

[0038] By setting an anti-deformation bowl mouth 9 on the outer end surface of the cylindrical process block 8, the outer wall of the cylindrical process block 8 is thin-walled. During casting, the thin wall of the bowl mouth cools quickly and is subjected to tensile stress; the inner side of the cylindrical process block 8 cools slowly and is subjected to compressive stress. During the annealing process, the stress is relaxed, the thin wall of the bowl mouth shrinks, and a closed mouth is formed, which drives the inner side of the cylindrical process block 8 to expand outward, and can balance the closing trend of the lug plate 4. That is, the anti-deformation bowl mouth 9 can not only reduce the amount of material used for the cylindrical process block 8, but also play a role in reverse anti-deformation. Example 3

[0039] Because the single-hole joint 2 of the semi-finished tie rod casting is not cylindrical in shape, it cannot be directly clamped using three types of chucks. In order to ensure the consistency of the outer circle size of the tie rod body 1, it is necessary to complete the turning of the entire outer circle in one clamping as much as possible, including the part where the ear plate 4 and the tie rod body 1 are coplanar.

[0040] Based on the above embodiment 2, Figure 7 and Figure 8 As shown, when turning the outer circle of the pull rod body 1 in step S3, the turning tool 11 is used to clamp the single hole joint 2.

[0041] By adding a turning tool 11 to clamp the single-hole joint 2, all the outer cylindrical parts of the pull rod body 1 and the lug plate 4 are freed, so that the entire outer cylindrical surface can be completed by turning at one time.

[0042] Specifically, if Figure 7 and Figure 8 As shown, the turning tool 11 is in the shape of a short cylinder, and the outer wall contacts the claws of the three-jaw chuck of the lathe, that is, the three-jaw chuck of the lathe spindle box is used to directly load the outer circle of the turning tool 11. A mounting groove 111 is centrally provided on the end face of the turning tool 11 facing the single-hole joint 2. The cross section of the mounting groove 111 is in the shape of an isosceles triangle, and the two oblique waist surfaces of the mounting groove 111 are respectively in contact with the outer arc wall of the single-hole joint 2. The width of the mounting groove 111 is adapted to the thickness of the single-hole joint 2, that is, the single-hole joint 2 can be inserted into the mounting groove 111, and the two are clearance-matched.

[0043] By providing a clamping groove 111 in the center of the outer end surface of the turning tool 11, the clamping groove 111 is adapted to the outer arc wall of the single-hole joint 2, and can also prevent circumferential rotation under the premise of automatic centering.

[0044] Specifically, if Figure 8 As shown, when turning the outer circle of the tie rod body 1 in step S3, the tie rod casting semi-finished product uses a chuck to clamp the cylindrical process block 8 at the other end or uses a lathe center 12 to abut against the center hole 10.

[0045] Specifically, an annular stop is further provided on the outer wall of the turning tool 11 , and the annular stop is limited on the end surface of the jaws of the three-jaw chuck, so that the turning tool 11 can be quickly positioned and loaded.

[0046] By using the turning tool 11 and the lathe top 12 in coordination, the outer cylindrical part to be processed is completely cleared, the turning difficulty is reduced, and the turning dimensional accuracy can be significantly improved. By adding the annular stop, it is convenient to quickly locate and load the turning tool 11.

[0047] In summary, the tie rod production process of the present invention, by adding a cylindrical process block 8 to the cantilever end of the lug plate 4, is equivalent to providing an auxiliary support at the cantilever ends of the two lug plates 4. During the annealing process, the cantilever end of the lug plate 4 is blocked by the cylindrical process block 8 during the residual stress release process and will not close inward, so that the distance between the two lug plates 4 will not be reduced due to deformation. The tie rod production process of the present invention can reduce the heat treatment deformation of the tie rod casting semi-finished product, improve the yield rate, and improve production efficiency. In addition, by forming a concave thinning platform 7 on the side of the lug plate 4 away from the ear groove 6, the two sides of the connection between the root of the lug plate 4 and the tie rod body 1 are roughly the same, reducing the left and right swing deformation of the lug plate 4 during the heat treatment process. At the same time, the thinning platform 7 reduces the material consumption without almost reducing the strength of the lug plate 4, and the setting of the thinning platform 7 is also convenient for the expansion of the rear pin shaft hole 5. By adding a top hole 10 on the outer end face of the cylindrical process block 8, the lathe top 12 can be used for auxiliary support when clamping the semi-finished pull rod casting. By setting an anti-deformation bowl mouth 9 on the outer end face of the cylindrical process block 8, the outer wall of the cylindrical process block 8 is thin-walled. During casting, the thin wall of the bowl mouth cools quickly and is subject to tensile stress; the inner side of the cylindrical process block 8 cools slowly and is subject to compressive stress. During the annealing process, the stress relaxes, the thin wall of the bowl mouth shrinks, and a closed mouth is formed, which drives the inner side of the cylindrical process block 8 to expand outward, and can balance the closing trend of the lug plate 4. That is, the anti-deformation bowl mouth 9 can not only reduce the amount of material used in the cylindrical process block 8, but also play a role in reverse anti-deformation. By adding a turning tool 11 to clamp the single-hole joint 2, all the outer cylindrical parts of the pull rod body 1 and the lug plate 4 are freed, so that the entire outer cylindrical surface can be completed by lathe machining at one time. By providing a mounting groove 111 in the center of the outer end surface of the turning tool 11, the mounting groove 111 is adapted to the outer arc wall of the single-hole joint 2, and can also prevent circumferential rotation under the premise of automatic centering. By using the turning tool 11 and the lathe center 12 in coordination, the outer circle part to be processed is completely given up, the turning difficulty is reduced, and the turning dimensional accuracy can be significantly improved. By adding the annular stop, it is convenient to quickly position and mount the turning tool 11.

[0048] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0049] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A tie rod production process, characterized in that: The following steps are involved: S1. Sand casting, using cast iron molten iron to cast and produce a tie rod casting semi-finished product; wherein the tie rod casting semi-finished product further comprises a cylindrical process block (8), wherein the cylindrical process block (8) is integrally connected to the cantilever end of the lug plate (4) and is coaxially arranged with the tie rod body (1); the cylindrical process block (8) is connected to the end faces of both lug plates (4), and the outer diameter of the cylindrical process block (8) is smaller than the outer diameter of the tie rod body (1); S2, heat treatment, annealing the semi-finished tie rod casting; S3, machining, turning the outer circle of the pull rod body (1), expanding the front pin shaft hole (3) and the rear pin shaft hole (5), and removing the cylindrical process block (8); S4, surface treatment, painting or plastic spraying.

2. The tie rod production process according to claim 1, characterized in that: The tie rod casting semi-finished product further comprises a thinning platform (7), wherein the thinning platform (7) is formed on a side of the ear plate (4) away from the ear groove (6); the length of the thinning platform (7) is aligned with the ear groove (6).

3. The tie rod production process according to claim 2, characterized in that: The bottom surface of the thinning table (7) is perpendicular to the axis of the rear pin shaft hole (5), and the distance between the two thinning tables (7) is greater than the outer diameter of the cylindrical process block (8).

4. The tie rod production process according to claim 1, characterized in that: A top hole (10) is also coaxially arranged on the outer end surface of the cylindrical process block (8).

5. The tie rod production process according to claim 4, characterized in that: An anti-deformation bowl mouth (9) is also coaxially arranged on the outer end surface of the cylindrical process block (8), and the top hole (10) is arranged on the bottom surface of the anti-deformation bowl mouth (9).

6. The tie rod production process according to claim 4, characterized in that: When turning the outer circle of the pull rod body (1) in step S3, a turning tool (11) is used to clamp the single hole joint (2).

7. The tie rod production process according to claim 6, characterized in that: The turning tool (11) is in the shape of a short cylinder, and its outer wall contacts the clamping jaws of the three-jaw chuck of the lathe; a clamping groove (111) is centrally provided on the end surface of the turning tool (11) facing the single-hole joint (2); the cross-section of the clamping groove (111) is in the shape of an isosceles triangle, and two oblique waist surfaces of the clamping groove (111) respectively abut against the outer arc wall of the single-hole joint (2); the width of the clamping groove (111) is adapted to the thickness of the single-hole joint (2).

8. The tie rod production process according to claim 6, characterized in that: When turning the outer circle of the tie rod body (1) in step S3, the other end of the tie rod casting semi-finished product is chucked with the cylindrical process block (8) or a lathe center (12) is used to abut against the center hole (10).

9. The tie rod production process according to claim 1, characterized in that: In step S3, when removing the cylindrical process block (8), an angle grinder is used to install a cutting blade to cut off the cylindrical process block (8) from the end surface of the support ear plate (4).

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