Box-in-box beam casting structure

Abstract

The utility model relates to a box-in-box beam casting structure, and relates to the field of machine tool part manufacturing, the box-in-box beam casting structure comprises a side beam casting and an end beam casting, and the side beam casting and the end beam casting are both hollow box type structures; the side beam casting comprises connecting parts located at the two ends and a supporting part located between the connecting parts at the two ends, the end beam casting is connected between the connecting parts at the same end of the side beam casting to form a box-in-box casting structure, and a plurality of casting holes are formed in the side wall of the side beam casting. And a plurality of operation holes are formed in the side wall of the supporting part, and the area of the operation holes is larger than that of the casting holes, so that the casting convenience of the casting can be improved.

Description

Technical Field

[0001] This application relates to the field of machine tool component manufacturing, and in particular, to a box-in-box crossbeam casting structure. Background Art

[0002] A gantry machine tool is a high-end processing equipment for large-scale machining. With a gantry machine tool, the overall machining of large mechanical parts can be carried out, the machining accuracy of large parts can be improved, and an effective guarantee is provided for the manufacturing of large high-precision equipment.

[0003] A gantry machine tool is a machine tool with a gantry frame and a horizontal long bed. The crossbeam of the gantry machine tool is supported on the columns on both sides and can move along the rails with the columns to form the gantry frame of the gantry machine tool. The ram is installed on the crossbeam and can slide left and right and move up and down on the crossbeam. A cutting tool installed at the lower part of the ram is used to perform cutting machining on large machinery. In order to be able to machine larger large parts, the crossbeam usually has a longer length; and in order to carry the ram and the cutting tool installed at the lower part of the ram and maintain the position accuracy of the cutting tool under the condition that the cutting tool bears a greater cutting force, the crossbeam usually has a larger cross-sectional area, which will cause a significant increase in the weight of the crossbeam, not only increasing the support burden of the columns, but also increasing the moment of inertia when the crossbeam moves, affecting the control difficulty and positioning accuracy of the crossbeam. For this reason, the crossbeam of a large gantry machine tool usually adopts a box-in-box crossbeam formed by connecting two hollow end beam box castings and two hollow side beam box castings. The ram is installed in the gap between the two side beam castings, while reducing the weight of the crossbeam, ensuring the positioning accuracy of the ram and the cutting tool fixed on the ram.

[0004] In order to facilitate the casting of the hollow box castings used in the box-in-box crossbeam, casting holes are usually provided on the side walls of the box castings. By setting the casting holes, a release agent can be applied to the casting mold during the casting process, and the sand grains remaining in the casting during the casting process can be removed after casting. In order to reduce the influence of the setting of the casting holes on the mechanical strength of the casting, the casting holes on the side walls of the existing box castings are usually set to be small, which affects the convenience of casting the casting and is not conducive to reducing the weight of the casting structure. Summary of the Invention

[0005] In order to improve the convenience of casting the casting, this application provides a box-in-box crossbeam casting structure.

[0006] The box-in-box crossbeam casting structure provided by this application adopts the following technical solutions:

[0007] A crossbeam casting structure of a box-in-box, comprising side beam castings and end beam castings. Both the side beam castings and the end beam castings are hollow box-shaped structures. The side beam castings include connecting parts at both ends and a supporting part between the connecting parts at both ends. The end beam castings are connected between the connecting parts at the same end of the side beam castings to form a box-in-box casting structure. A plurality of casting holes are provided on the side walls of the side beam castings, and a plurality of operation holes are provided on the side walls of the supporting part. The area of the operation holes is larger than the area of the casting holes.

[0008] By adopting the above technical solution, by using a plurality of casting holes provided on the side walls of the side beam castings, some simple operations can be carried out on the mold during the casting process or on the inside of the casting after casting is completed. At the same time, the influence of setting the casting holes on the side wall strength of the casting is reduced by the smaller area of the casting holes; by using the operation holes with a larger area provided on the side walls of the supporting part, some more complex operations can be carried out on the mold during the casting process or on the inside of the casting after casting is completed, such as inserting tools into the inside of the mold or the casting to apply a release agent, or treating sand grains or casting burrs adhered to the inner wall of the casting during the casting process. And by arranging the operation holes with a larger area on the supporting part in the middle of the side beam castings, the influence of setting the operation holes on the overall bearing capacity of the side beam castings is reduced.

[0009] In a specific feasible implementation scheme, the casting holes are provided in the upper part of the side wall of the side beam castings, and the operation holes are provided in the lower part of the side wall of the side beam castings.

[0010] By adopting the above technical solution, since the upper part of the side beam casting mainly bears extrusion force and the lower part mainly bears tensile force, using smaller-area casting holes provided in the upper part of the side beam casting is beneficial to reducing the influence of the holes on the compressive performance of the upper part of the side beam casting; and the influence of the holes on the tensile performance of the casting is relatively small. Arranging the operation holes in the lower part of the side beam casting is also beneficial to reducing the influence of the larger area of the operation holes on the tensile performance of the lower part of the side beam casting.

[0011] In a specific feasible implementation scheme, the casting holes are round holes, and the operation holes are square holes with edges parallel to the side edges of the side beam castings.

[0012] By adopting the above technical solution, using the circular shape of the casting holes is beneficial to improving the compressive performance of the casting around the casting holes and reducing the influence of the holes on the compressive capacity of the side beam castings; the square operation holes with edges parallel to the side edges of the side beam castings can form an equal-width solid structure around the operation holes, which is beneficial to ensuring the tensile capacity of the lower part of the side beam castings.

[0013] In a specific feasible implementation scheme, the height of the operation holes adjacent to the middle part of the side wall of the supporting part is not less than the height of the operation holes adjacent to the two side parts of the side wall of the supporting part.

[0014] By adopting the above technical solution, with the height of the operation hole in the middle of the support part being greater than that of the operation holes on both sides, the mechanical strength on both sides of the support part can be made greater than that in the middle, which conforms to the stress state where the bearing capacity on both sides of the cross beam of the inner box in the outer box is greater and the bearing capacity in the middle is smaller under the condition of a relatively large self-weight, and is beneficial to the balance of the overall bearing capacity of the cross beam casting structure of the inner box in the outer box of the present application.

[0015] In a specific feasible implementation scheme, a plurality of support ribs are arranged in the hollow cavity inside the side beam casting. The support ribs include transverse support ribs, longitudinal support ribs and inclined support ribs. The transverse support ribs and the longitudinal support ribs are cross-connected with each other and are connected to the side wall of the side beam casting. The inclined support ribs are connected between the transverse support ribs and / or the longitudinal support ribs.

[0016] By adopting the above technical solution, by using the support ribs in the hollow cavity inside the side beam casting, the side wall of the side beam casting can be strengthened, so that sufficient mechanical strength can be provided with a relatively small side wall thickness of the side beam casting, which is beneficial to reducing the self-weight of the side beam casting and reducing the moment of inertia of the cross beam of the inner box in the outer box. By using the structure in which the transverse support ribs, longitudinal support ribs and inclined support ribs are cross-connected with each other, mutual support and strengthening between the transverse support ribs, longitudinal support ribs and inclined support ribs can be formed, effectively improving the support effect of the support ribs inside the side beam casting, so that sufficient mechanical strength can be formed by fewer support ribs, reducing the number of support ribs arranged, and further reducing the self-weight of the side beam casting.

[0017] In a specific feasible implementation scheme, the inclined support ribs are arranged in the support part, and the inclined support ribs are inclined obliquely from the lower part on both sides of the support part to the upper part in the middle of the support part.

[0018] By adopting the above technical solution, by using the inclined support ribs arranged in the support part, the tangential bearing capacity borne by the support part can be resisted, effectively improving the support effect on the support part and enhancing the overall mechanical strength of the side beam casting. By using the setting that the inclined support ribs are inclined obliquely from the lower part on both sides of the support part to the upper part in the middle, the stress direction formed by the support part bearing the tangential load can be made consistent with the extension direction of the inclined support ribs, improving the support effect of the inclined support ribs.

[0019] In a specific feasible implementation scheme, the inclined support ribs located in the middle of the support part are arranged in the upper area of the support part, and the inclined support ribs located in the parts on both sides of the support part are arranged in the lower area of the support part.

[0020] By adopting the above technical solution, the inclined support ribs arranged in the upper region of the middle position of the support part can effectively resist the extrusion force formed at the middle position of the support part under the action of the tangential force, which is beneficial to reducing the tangential strain at the middle position of the support part. The inclined support ribs arranged in the lower regions of both sides of the support part can improve the tangential bearing capacity of both sides of the support part, which is beneficial to improving the overall mechanical strength of the side beam casting.

[0021] In a specific feasible implementation, weight-reducing holes are provided on the transverse support ribs, longitudinal support ribs and inclined support ribs.

[0022] By adopting the above technical solution, by using the weight-reducing holes respectively arranged on the transverse support ribs, longitudinal support ribs and inclined support ribs, while providing sufficient support force for the side beam casting, the weight of the support ribs can be reduced, and further the self-weight of the box-in-box cross beam casting structure of the present application can be reduced.

[0023] In a specific feasible implementation, a plurality of the operation holes are provided on the bottom wall of the support part.

[0024] By adopting the above technical solution, by using the operation holes arranged on the bottom wall of the support part, while facilitating the operation of the interior of the support part, the influence of the operation holes on the bearing capacity of the support part can be reduced.

[0025] In a specific feasible implementation, a plurality of end beam operation holes are provided on both the top wall and the bottom wall of the end beam casting.

[0026] By adopting the above technical solution, by using the operation holes arranged on the top wall and the bottom wall of the end beam casting, while improving the convenience of the casting process of the end beam casting, the influence on the load capacity of the end beam casting supported on the column is smaller.

[0027] In summary, the present application includes at least one of the following beneficial technical effects:

[0028] 1. By providing a plurality of casting holes and operation holes on the side wall of the side beam casting, different types of operations can be carried out on the casting mold and the casting, while improving the convenience of the casting process, reducing the influence of setting the operation holes on the continuous strength of the side beam casting.

[0029] 2. By arranging the operation holes at the lower part of the side wall of the support part of the side beam casting and setting the height of the middle part of the operation holes to be greater than the height of the operation holes at both sides, the distribution of the operation holes is adapted to the actual stress condition of the side beam casting, so as to reduce the influence of the operation holes on the load-bearing of the side beam casting to a greater extent and be able to reduce the self-weight of the side beam casting to a greater extent.

[0030] 3. By arranging diagonal support ribs inside the inner cavity of the side beam casting, effective support can be provided to the side beam casting, the influence of setting operation holes on the side wall of the side beam casting on the mechanical strength of the side beam casting can be reduced, and sufficient bearing capacity can be formed with a smaller structural weight, thereby reducing the self-weight of the side beam casting.

[0031] 4. By arranging the diagonal support ribs in the upper region of the middle position of the support part and the lower regions of both sides, and arranging the diagonal support ribs to incline obliquely from the lower sides of both sides of the support part to the upper middle, the inclination direction of the diagonal support ribs can be coordinated with the stress nature and stress direction of the support part, effectively improving the support effect of the diagonal support ribs and enhancing the bearing capacity of the measured casting. Description of the Drawings

[0032] Figure 1 It is a schematic diagram of an embodiment of the present application.

[0033] Figure 2 It is a schematic diagram of another perspective of an embodiment of the present application.

[0034] Figure 3 It is a partial cross-sectional view of the side beam casting in an embodiment of the present application.

[0035] Figure 4 It is a simulation diagram of the deformation amount under a load of 50,000 N in an embodiment of the present application.

[0036] Figure 5 It is a simulation diagram of the deformation amount under a load of 50,000 N for an existing box-in-box cross beam casting structure.

[0037] Description of the Reference Numerals: 1, side beam casting; 101, connecting part; 102, support part; 11, casting hole; 12, operation hole; 13, transverse support rib; 14, longitudinal support rib; 15, diagonal support rib; 16, weight reduction hole; 2, end beam casting; 21, end beam operation hole. Detailed Embodiments

[0038] The following will describe the detailed embodiments of the present application with reference to the drawings. It should be understood that the detailed embodiments described herein are only for explaining and illustrating the present application, and are not used to limit the present application.

[0039] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "arrange" and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0040] An embodiment of the beam casting structure of the inner box in the present application is as follows Figure 1 and Figure 2 shown, including side beam castings 1 and end beam castings 2. The side beam castings 1 and the end beam castings 2 are respectively cast, and both are hollow box-shaped casting structures usually formed by lost foam casting.

[0041] Both ends in the length direction of the side beam casting 1 are connecting parts 101, and the part between the two end connecting parts 101 is the support part 102 of the side beam casting 1. The inner box casting structure of the present application usually includes two side beam castings 1 and two end beam castings 2. The two side beam castings 1 are arranged in parallel with each other, and the two end beam castings 2 are respectively fixedly connected between the connecting parts 101 at the corresponding ends of the side beam castings 1 to form the inner box casting structure.

[0042] A plurality of casting holes 11 are provided on the side wall of the side beam casting 1. Through the plurality of casting holes 11, casting sand can be added into the lost foam during casting for sand casting operation to form the cavity structure inside the side beam casting 1 and the internal and external shapes of the side beam casting. A plurality of operation holes 12 are also provided on the side wall of the support part 102. The area of the operation holes 12 is usually larger than the area of the casting holes 11. Through the operation holes 12 with a larger area, a brush can be conveniently inserted into the lost foam to apply a release agent on the inner wall of the lost foam, so that the release agent can cover the surface of the casting sand after sand casting, facilitating the demolding of the side beam casting 1 after casting. And after the side beam casting 1 is demolded, an appropriate tool can be inserted into the cavity inside the side beam casting 1 through the operation holes 12 to clean the sand in the cavity, remove the sand grains adhering to the cavity wall, and even trim and polish the casting burrs on the inner cavity wall of the side beam casting 1.

[0043] Through the mixed arrangement of the casting holes 11 with a smaller area and the operation holes 12 with a larger area, it not only ensures the setting density of the holes on the surface of the side beam casting 1, ensures the necessary operations on different parts inside the casting mold and inside the side beam casting 1, and improves the convenience of operations on the inside of the casting mold and inside the side beam casting 1 through the operation holes 12 at different positions, but also can prevent the excessive decrease of the mechanical strength of the side beam casting 1 caused by setting too many operation holes 12 with a large area on the side of the side beam casting 1, affecting the bearing capacity of the side beam casting 1.

[0044] In some embodiments of the beam casting structure of the inner box in the present application, as Figure 1 and Figure 2 shown, the casting holes 11 on the side wall of the side beam casting 1 are arranged on the upper part of the side wall of the side beam casting 1, while the operation holes 12 arranged on the side wall of the side beam casting 1 are usually arranged on the lower part of the side wall of the side beam casting 1.

[0045] When the box-in-box crossbeam casting structure of the present application is installed on the gantry column for use, the upper part of the side beam casting 1 mainly bears extrusion force. Setting the casting hole 11 with a smaller area on the upper part of the side wall of the side beam casting 1 can reduce the influence of the hole on the compressive capacity of the upper part of the side beam casting 1 and ensure the load-bearing performance of the side beam casting 1. The lower part of the side beam casting 1 mainly bears tensile force, and the influence of the hole on the tensile performance of the metal casting is relatively small. Setting the operation hole 12 with a larger area on the lower part of the side wall of the side beam casting 1 has a relatively small influence on the tensile capacity of the lower part of the side beam casting 1, and can reduce the influence of the operation hole 12 with a larger area on the load-bearing performance of the side beam casting 1.

[0046] In a preferred embodiment of the box-in-box crossbeam casting structure of the present application, as Figure 1 and Figure 2 shown, the casting hole 11 is usually set as a circular hole with a diameter of 120 mm. The hole wall of the circular hole has better compressive performance. Setting the casting hole 11 on the upper part of the side beam casting 1 as a circular hole is beneficial to reducing the influence of the casting hole 11 on the compressive performance of the upper part of the side beam casting 1. The operation hole 12 is set as a square hole with its edges parallel to the side edge of the side beam casting 1, that is, the upper and lower sides are horizontal and the left and right sides are vertical. It is usually set as a square hole with a width of 180 mm and unequal heights. Setting the operation hole 12 as a square hole with a horizontal bottom edge can form a casting metal strip with the same width below the operation hole 12, ensure the balanced tensile capacity of the lower part of the side beam casting 1, and is beneficial to reducing the influence of the operation hole 12 on the tensile performance of the lower part of the side beam casting 1.

[0047] As a specific implementation manner of the box-in-box crossbeam casting structure of the present application, as Figure 1 and Figure 2 shown, the height of the operation hole 12 set in the middle part of the side wall of the support part 102 is greater than or equal to the height of the operation hole 12 set in the two side parts, so that the height of the operation hole on the side wall of the support part 102 shows a gradually decreasing trend as the setting position changes from the middle to both sides. In a specific embodiment, the height of the operation hole 12 set in the middle of the support part 102 is 300 mm, the height of the operation hole 12 set at the two side edges is 120 mm, and the height of the operation hole 12 set between the two is between the two.

[0048] When the self-weight of the side beam casting 1 is relatively large, generally from the middle to both sides of the support part 102, the tangential force borne by the support part 102 gradually increases. Setting the height of the operation hole 12 to gradually decrease from the middle to both sides can also make the tangential pressure-bearing capacity of the two sides of the support part 102 larger and the tangential pressure-bearing capacity of the middle part smaller, which is adapted to the actual tangential force borne by the support part 102 and is beneficial to improving the overall load-bearing performance of the support part 102.

[0049] In some embodiments of the box-in-box crossbeam casting structure of the present application, asFigure 3 As shown, a plurality of support ribs are provided in the hollow cavity inside the side beam casting 1. The plurality of support ribs are arranged in different directions in the cavity inside the side beam casting 1. According to the different extension directions, the support ribs in the cavity of the side beam casting 1 include a transverse support rib 13 arranged in the horizontal direction, a longitudinal support rib 14 arranged in the vertical direction, and an inclined support rib 15 arranged obliquely.

[0050] Similar to the side beam casting in the existing structure of the box-in-box crossbeam casting, the transverse support rib 13 in the cavity of the side beam casting 1 is connected to the side wall of the side beam casting 1 on the horizontal plane, and the longitudinal support rib 14 is connected to the side wall of the side beam casting 1 on the vertical plane, and the two are cross-connected to form a grid-like support in the cavity of the side beam casting 1. An inclined support rib 15 is also provided in the cavity of the side beam casting 1 of the present application. The inclined support rib 15 can be connected between adjacent transverse support ribs 13, or can be connected between adjacent longitudinal support ribs 14, or can also be connected between adjacent transverse support ribs 13 and longitudinal support ribs 14.

[0051] Compared with the structure in which only transverse support ribs and longitudinal support ribs are provided inside the side beam casting of the existing box-in-box crossbeam casting structure, the setting of the inclined support rib 15 can conform to the stress direction of the box-in-box crossbeam casting structure, further reinforce the transverse support rib 13 and the longitudinal support rib 14, and effectively improve the support strength of the side beam casting 1. Under the same stress environment, the number of support ribs provided inside the side beam casting 1 can be reduced. According to the analysis of the stress on the support ribs, some support ribs with smaller stress bearing can be cancelled, which can further reduce the self-weight of the side beam casting 1 and reduce the moment of inertia of the box-in-box crossbeam casting structure.

[0052] In a preferred embodiment of the box-in-box crossbeam casting structure of the present application, as Figure 3 shown, the inclined support rib 15 is arranged inside the support portion 102. When the box-in-box crossbeam casting structure is installed on the gantry column and used, the connecting portion 101 is usually supported at the top of the gantry column and does not bear the suspension force of the ram and the cutting tool under the action of the gantry column. Arranging the inclined support rib 15 inside the support portion 102 that bears the suspension force can specifically improve the ability of the support portion 102 to bear the tangential suspension force.

[0053] The inclined support rib 15 is arranged inside the support portion 102 to incline from the lower sides of the support portion 102 to the upper part of the middle of the support portion 102. So that the inclination direction of the inclined support rib 15 is consistent with the stress direction after the side beam casting 1 is installed on the gantry column, effectively improving the support effect of the inclined support rib 15.

[0054] As a specific implementation manner of the box-in-box crossbeam casting structure of the present application, as Figure 3As shown in the figure, the diagonal support ribs 15 provided near the middle part of the support part 102 are arranged in the upper area of the support part 102, specifically in the area above the transverse support rib 13. The diagonal support ribs 15 provided near both ends of the support part 102 are arranged in the lower area of the support part 102, specifically in the area below the transverse support rib 13. Such an arrangement enables the diagonal support ribs to be set at the positions where the stress in the side beam casting 1 is relatively concentrated, which can effectively disperse the stress borne by the local area and make the strain distribution in the side beam casting 1 more uniform.

[0055] In a preferred embodiment of the box-in-box crossbeam casting structure of the present application, as Figure 3 shown, weight-reducing holes 16 are provided on the transverse support ribs 13, longitudinal support ribs 14, and diagonal support ribs 15. The specific shape and size of the weight-reducing holes 16 are determined according to the stress conditions of the support ribs. Smaller weight-reducing holes 16 are provided on the support ribs that bear greater stress, or no weight-reducing holes are provided; larger weight-reducing holes are provided on the support ribs that bear smaller stress. Square weight-reducing holes 16 are usually provided on the transverse support ribs 13 and longitudinal support ribs 14, while circular weight-reducing holes 16 are usually provided on the diagonal support ribs 15. By providing the weight-reducing holes 16, the weight of the support ribs can be reduced, and further the self-weight of the side beam casting 1 can be reduced.

[0056] In some embodiments of the box-in-box crossbeam casting structure of the present application, as Figure 2 shown, a plurality of operation holes 12 are provided on the bottom wall of the support part 102. The operation holes 12 on the bottom wall of the support part 102 are set to be square, and the plurality of square operation holes 12 are arranged linearly along the length direction on the bottom wall of the support part 102. By providing the operation holes 12 on the bottom wall of the support part 102, the self-weight of the side beam casting 1 can be further reduced.

[0057] In some embodiments of the box-in-box crossbeam casting structure of the present application, as Figures 1 to 3 shown, a plurality of circular end beam casting holes are provided on the inner and outer side walls of the end beam casting 2, and a plurality of end beam operation holes 21 are provided on both the top wall and the bottom wall of the end beam casting 2. The end beam operation holes 21 are also set to be large-area direction holes, and the plurality of end beam operation holes 21 are arranged in an array on the top wall and the bottom wall of the end beam casting 2. Specifically, the diameter of the end beam casting holes is set to 100 mm, and the size of the end beam operation holes 21 is set to 115 * 132 mm 2 。

[0058] Since the structure of the box-in-box crossbeam casting in this application is in the use state, while connecting the side beam castings on both sides, the end beam casting 2 is supported on the columns of the gantry. The stress borne by the upper and lower side walls of the end beam casting 2 is relatively small. Setting end beam operation holes 21 with a relatively large area on the top and bottom walls of the end beam casting 2 has little impact on the mechanical strength of the end beam casting 2, but significantly reduces the weight of the end beam casting 2.

[0059] In order to verify the bearing performance of the box-in-box crossbeam casting structure of this application, the inventor used the Simulation plug-in of SOLIDWORKS to simulate the deformation of a preferred embodiment of the box-in-box crossbeam casting structure of this application and a commonly used box-in-box crossbeam casting structure under load. The simulation results of the two are respectively as Figure 4 and Figure 5 shown. Under the condition of the same overall appearance shape and overall external dimensions, the self-weight of the box-in-box crossbeam casting structure of this application is 6620 Kg. Under the condition of applying a load force of 50000 N, the maximum deformation of the side beam casting 1 is 0.029 mm; while the self-weight of the commonly used box-in-box crossbeam casting structure is 6970 Kg. Under the condition of applying a load force of 50000 N, the maximum deformation of the side beam casting is 0.032 mm. It can be seen that compared with the commonly used box-in-box crossbeam casting structure, the preferred embodiment of the box-in-box crossbeam casting structure of this application not only reduces the self-weight by 350 Kg, but also reduces the maximum deformation under the load state of 50000 N. While improving the casting convenience, it reduces the self-weight of the box-in-box crossbeam casting structure, and the load capacity of the box-in-box crossbeam casting structure is also improved, having better application value.

[0060] In the description of this application, the descriptions referring to terms such as "one embodiment", "specific embodiment", "preferred embodiment", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this application, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0061] The above are all the preferred embodiments of this application, and do not limit the protection scope of this application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A structure of a crossbeam casting in a box-in-box, comprising side beam castings (1) and end beam castings (2). Both the side beam castings (1) and the end beam castings (2) are hollow box-shaped structures. The side beam castings (1) include connecting parts (101) at both ends and a supporting part (102) between the connecting parts (101) at both ends. The end beam castings (2) are connected between the connecting parts (101) at the same end of the side beam castings (1) to form a box-in-box casting structure, characterized in that: A plurality of casting holes (11) are provided on the side wall of the side beam casting (1), a plurality of operation holes (12) are provided on the side wall of the support portion (102), and the area of the operation hole (12) is larger than the area of the casting hole (11).

2. The structure of the crossbeam casting in the box-in-box according to claim 1, wherein: The casting holes (11) are provided in the upper part of the side wall of the side beam casting (1), and the operation holes (12) are provided in the lower part of the side wall of the side beam casting (1).

3. The structure of the crossbeam casting in the box-in-box according to claim 2, characterized in that: The casting holes (11) are circular holes, and the operation holes (12) are square holes with edges parallel to the side edge of the side beam casting (1).

4. The structure of the crossbeam casting in the box-in-box according to claim 3, characterized in that: The height of the operation hole (12) adjacent to the middle part of the side wall of the support portion (102) is not less than the height of the operation hole (12) adjacent to the two side parts of the side wall of the support portion (102).

5. The structure of the crossbeam casting in the box-in-box according to claim 1, characterized in that: A plurality of support ribs are provided in the hollow cavity inside the side beam casting (1). The support ribs include transverse support ribs (13), longitudinal support ribs (14), and inclined support ribs (15). The transverse support ribs (13) and the longitudinal support ribs (14) are cross-connected to each other and are connected to the side wall of the side beam casting (1). The inclined support ribs (15) are connected between the transverse support ribs (13) and / or the longitudinal support ribs (14).

6. The structure of the crossbeam casting in the box-in-box according to claim 5, wherein: The inclined support ribs (15) are provided in the support portion (102), and the inclined support ribs (15) are inclined obliquely from the lower sides of both sides of the support portion (102) to the upper part of the middle of the support portion (102).

7. The structure of the crossbeam casting in the box-in-box according to claim 6, characterized in that: The inclined support ribs (15) located in the middle of the support portion (102) are provided in the upper region of the support portion (102), and the inclined support ribs (15) located in the two side parts of the support portion (102) are provided in the lower region of the support portion (102).

8. The structure of the crossbeam casting in the box-in-box according to claim 5, characterized in that: Weight-reducing holes (16) are provided on the transverse support ribs (13), longitudinal support ribs (14), and inclined support ribs (15).

9. The structure of the crossbeam casting in the box-in-box according to any one of claims 1-8, characterized in that: A plurality of the operation holes (12) are provided on the bottom wall of the support portion (102).

10. The structure of the crossbeam casting in the box-in-box according to any one of claims 1-8, characterized in that: A plurality of end beam operation holes (21) are provided on both the top wall and the bottom wall of the end beam casting (2).

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