Telescopic assembly for load, mechanical arm, supporting leg and construction machine

Abstract

The utility model discloses a telescopic assembly for a load, and the telescopic assembly comprises at least one telescopic joint which is a hollow shell and comprises a first stress part, a second stress part and a third stress part, the first stress part is located above the cross section, and at least part of the contour of the cross section in the horizontal direction is an arc-shaped or approximately arc-shaped polygon; the second stress part is located below the cross section, and at least part of the outline of the cross section in the horizontal direction is in a circular arc shape or a polygon similar to a circular arc shape; the connecting part is connected between the first stress part and the second stress part, and at least part of the outline of the cross section of the connecting part in the horizontal direction is linear; the cross sections, in the horizontal direction, of the first stress part, the second stress part and the connecting part are in an axial symmetry shape and have the same symmetry axis. And the radius of the at least approximately arc-shaped outline part of the cross section of the first stress part along the horizontal direction is smaller than that of the at least approximately arc-shaped outline part of the cross section of the second stress part along the horizontal direction.

Description

Technical Field

[0001] The present application relates to the technical field of construction machinery, and in particular to a telescopic assembly for carrying a load, a mechanical arm, a support leg, and a construction machinery. Background Art

[0002] The boom is one of the core components of a mobile crane, responsible for lifting heavy objects to a specified height. It is widely used in construction, firefighting, logistics and other fields. Taking the telescopic boom as an example, its structure consists of a multi-section boom. The length is adjusted by the telescopic action of the inner section boom relative to the outer arm, thereby changing the effective working range of the boom. The safety, stability and reliability of the boom are key indicators for evaluating the performance of a crane. During the actual lifting process, the boom must bear the dual effects of the weight of the heavy object and its own weight. The large deformation deflection limits its lifting weight and accuracy. At the same time, because the boom operates under high stress and large strain conditions, the risk of fatigue cracking increases, further reducing the safety and reliability of construction equipment.

[0003] With the advancement of technology, the cross-sectional structure of the boom has undergone many rounds of improvements. In the early days, polygonal cross-sections such as quadrilaterals and hexagons were mostly used, while the current structure mainly uses U-shaped cross-sections. Common U-shaped cross-sections are mostly formed by bending and welding steel plates, and generally have one or two welds. However, longer welds and the number of welds can easily lead to structural defects and cracks, posing safety hazards. In addition, some cross-sections require complex bending and welding groove processing, which has high manufacturing costs and large processing errors, and is not conducive to large-scale production. At the same time, as telescopic boom cranes develop towards larger sizes, the size and height of the boom cross-sections have also increased. Traditional cross-sectional structures make it difficult to achieve uniform stress distribution, and local stress concentration can easily lead to local instability, making it difficult to meet the requirements of modern large cranes for comprehensive mechanical properties and stability. Utility Model Content

[0004] In order to solve the above-mentioned problems, the utility model provides a telescopic assembly for carrying a load, a mechanical arm, a support leg and a construction machine.

[0005] The utility model provides a telescopic assembly for carrying a load, wherein at least one telescopic section of the telescopic assembly is a hollow shell and comprises:

[0006] a first force-bearing portion, the first force-bearing portion being located above the cross section, and having at least a portion of the cross section along the horizontal direction being in the shape of an arc or a polygon approximately in the shape of an arc;

[0007] a second force-bearing portion, the second force-bearing portion being located below the cross section, and having at least a portion of a horizontal cross section having an arc shape or a polygonal shape approximately in the shape of an arc;

[0008] and a connecting portion connected between the first force receiving portion and the second force receiving portion, at least a part of a cross section of the connecting portion in a horizontal direction is linear;

[0009] The cross section of the first force receiving portion, the second force receiving portion and the connecting portion in the horizontal direction are all axisymmetric shapes and have a common axis of symmetry, a radius R1 of an at least approximately circular arc profile portion of the cross section of the first force receiving portion in the horizontal direction is smaller than a radius R2 of an at least approximately circular arc profile portion of the cross section of the second force receiving portion in the horizontal direction.

[0010] In an embodiment, the telescopic joint is integrally formed by the first force receiving portion, the connecting portion and the second force receiving portion along the axis of symmetry, and is free of welds.

[0011] In an embodiment, the thickness of the cross section gradually changes in each extension direction;

[0012] The thickness of the first force receiving portion gradually decreases in a direction from a rear section of the first force receiving portion to a front section of the first force receiving portion;

[0013] The thickness of the second force receiving portion gradually decreases in a direction from a rear section of the second force receiving portion to a front section of the second force receiving portion.

[0014] In an embodiment, at least a part of the thickness of the connecting portion is equal to at least a part of the thickness T1 of the first force receiving portion and at least a part of the thickness of the connecting portion is equal to at least a part of the thickness T3 of the second force receiving portion in the same cross section in the horizontal direction.

[0015] In an embodiment, at least one of the thickness T1 of at least a part of the first force receiving portion and the thickness T3 of at least a part of the second force receiving portion and the thickness of at least a part of the connecting portion is different from the thickness of at least a part of the first force receiving portion in the same cross section in the horizontal direction.

[0016] In an embodiment, the thickness T1 of at least a part of the first force receiving portion is smaller than the thickness T3 of at least a part of the second force receiving portion in the same cross section in the horizontal direction.

[0017] In an embodiment, the inner profile of the cross section of the telescopic joint in the horizontal direction intersects the axis of symmetry at a first intersection point and a second intersection point, a center of curvature C of the circular arc profile portion of the cross section of the first force receiving portion in the horizontal direction is on or near the axis of symmetry and is located between the first intersection point and a midpoint, a center of curvature D of the circular arc profile portion of the cross section of the second force receiving portion in the horizontal direction is on or near the axis of symmetry and is located between the second intersection point and the midpoint, and the midpoint is equidistantly arranged from the first intersection point and the second intersection point.

[0018] In one embodiment, the first force-bearing portion includes a first tensile stress portion having at least a partial contour of a cross section along the horizontal direction that is an arc or polygon and a second tensile stress portion having at least a partial contour of a cross section along the horizontal direction that is an arc or polygon, one end of the second tensile stress portion is connected to the first tensile stress portion, and the other end is connected to the connecting portion, the center of curvature C of the arc-shaped contour portion of the cross section of the first force-bearing portion along the horizontal direction is the center of curvature C of the arc-shaped contour portion of the cross section of the first tensile stress portion along the horizontal direction and the center of curvature C of the arc-shaped contour portion of the cross section of the second tensile stress portion along the horizontal direction, and the average thickness t11 of the first tensile stress portion is greater than the average thickness t12 of the second tensile stress portion.

[0019] In one embodiment, an angle α formed by a cross section of the first tensile stress portion along the horizontal direction and the symmetry axis is in the range of 0°<α≤45°.

[0020] In one embodiment, the second force-bearing portion includes a first compressive stress portion having at least a partial contour of a cross section along the horizontal direction that is an arc shape or a polygon, and a second compressive stress portion having at least a partial contour of a cross section along the horizontal direction that is an arc shape or a polygon, one end of the second compressive stress portion is connected to the first compressive stress portion, and the other end is connected to the connecting portion, the center of curvature D of the arc-shaped contour portion of the cross section of the second force-bearing portion along the horizontal direction is the center of curvature D of the arc-shaped contour portion of the cross section of the first compressive stress portion along the horizontal direction and the arc-shaped contour portion of the cross section of the second compressive stress portion along the horizontal direction, and the average thickness t31 of the first compressive stress portion is greater than the average thickness t32 of the second compressive stress portion.

[0021] In one embodiment, an angle β formed by a cross section of the first compressive stress portion along the horizontal direction and the symmetry axis is in the range of 0°<β≤45°.

[0022] Another embodiment of the present application further provides a robotic arm comprising the telescopic assembly.

[0023] Another embodiment of the present application further provides a supporting leg, comprising the telescopic assembly, for installing the telescopic assembly of the supporting leg upside down.

[0024] Another embodiment of the present application further provides a construction machine, comprising a chassis, the mechanical arm, and the supporting legs, wherein the mechanical arm and the supporting legs are located on the chassis.

[0025] The beneficial effect of the present invention is that at least part of the contour of the cross section of the first force-bearing part and the second force-bearing part along the horizontal direction is an arc-shaped or approximately arc-shaped polygon, and under the same cross section along the horizontal direction, the radius R1 of the arc-shaped contour part of the cross section of the first force-bearing part along the horizontal direction is smaller than the radius R2 of the arc-shaped contour part of the cross section of the second force-bearing part along the horizontal direction, so that the arc-shaped or approximately arc-shaped contour of the first force-bearing part of the telescopic joint is small and the arc-shaped or approximately arc-shaped contour of the second force-bearing part is large, forming a drop-shaped structure that is small at the top and large at the bottom as a whole, which can reduce the tensile stress and compressive stress from heavy objects or itself, enhance the overall bearing capacity of the telescopic assembly, and improve the structural stability and comprehensive mechanical properties. In addition, the telescopic joint is integrally formed by the first force-bearing part, the second force-bearing part and the connecting part, without welds, avoiding the risk of safety accidents caused by weld quality problems, extending the service life of the robotic arm, and reducing after-sales maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic cross-sectional view of an expansion joint along the horizontal direction according to an embodiment of the present invention.

[0028] Figure 2 This is a schematic cross-sectional view of an expansion joint along the horizontal direction according to an embodiment of the present invention.

[0029] Figure 3 This is a side view of an expansion joint according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present invention, and not all of them. Based on the description of the present invention, all other embodiments derived by persons of ordinary skill in the art without inventive effort are also within the scope of protection of the present invention.

[0031] In the description of this utility model, unless otherwise specified or limited, the terms "disposed," "installed," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms based on the specific circumstances.

[0032] The directions or positional relationships indicated by terms such as "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience and simplification of description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the utility model.

[0033] The terms "first," "second," "third," etc. are merely used to distinguish elements of similar nature and do not indicate or imply relative importance or a particular order.

[0034] The terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of elements other than the listed elements and may also include additional elements not specifically listed.

[0035] Please refer to Figure 1-3 , which shows a telescopic assembly for carrying a load provided in an embodiment of the present utility model, wherein at least one telescopic section included in the telescopic assembly is a hollow shell and includes:

[0036] A first force-bearing portion 1, the first force-bearing portion 1 is located above the cross section, and at least a portion of the cross section along the horizontal direction has an arc shape or a polygonal shape that is approximately arc-shaped;

[0037] A second force-bearing portion 3, the second force-bearing portion 3 is located below the cross section, and at least a portion of the cross section along the horizontal direction has an arc shape or a polygonal shape that is approximately arc-shaped;

[0038] and a connecting portion 2 connected between the first force-bearing portion 1 and the second force-bearing portion 3, wherein at least a portion of a cross-section of the connecting portion 2 along the horizontal direction is a straight line;

[0039] The cross-sections of the first force-bearing part 1, the second force-bearing part 3 and the connecting part 2 along the horizontal direction are all axially symmetrical and have a common axis of symmetry M. The radius R1 of the at least approximately circular arc-shaped contour portion of the cross-section of the first force-bearing part 1 along the horizontal direction is smaller than the radius R2 of the at least approximately circular arc-shaped contour portion of the cross-section of the second force-bearing part 3 along the horizontal direction.

[0040] The first force-bearing portion 1 is located above the cross section and is used to bear tensile stress. The cross section of the first force-bearing portion 1 along the horizontal direction may be in the shape of an arc (e.g. Figure 1 As shown), the area of ​​the cross-sectional shape structure can reduce tensile stress, has strong bending resistance, and can improve local stability; in another case, the profile of the cross section of the first force-bearing part 1 along the horizontal direction is an approximately circular arc composed of polygons (as shown Figure 2 As shown); Of course, it is also feasible that the profile of the cross section of the first force-bearing portion 1 along the horizontal direction is an approximate arc shape composed of short straight line segments and / or arc segments connected in sequence.

[0041] The second force-bearing portion 3 is located below the cross section and is used to bear compressive stress. The cross section of the second force-bearing portion 3 along the horizontal direction may be in the shape of an arc (e.g. Figure 1 As shown), the cross-sectional shape structure area can reduce the compressive stress, has strong bending resistance, and can improve local stability; in another case, the cross-sectional profile of the second force-bearing portion 3 along the horizontal direction is an approximately circular arc composed of polygons (as shown Figure 2 As shown); Of course, it is also feasible that the profile of the cross section of the second force-bearing portion 3 along the horizontal direction is an approximate arc shape composed of short straight line segments and / or arc segments connected in sequence.

[0042] The connecting portion 2 can be directly connected to the first force-bearing portion 1 and the second force-bearing portion 3, or can be tangentially connected to the first force-bearing portion 1 and / or the second force-bearing portion 3. The connecting portion 2 is used to withstand the local stress transmitted from the first force-bearing portion 1 and the second force-bearing portion 3. The cross-section of the connecting portion 2 along the horizontal direction is a straight line (e.g. Figure 1-2 As shown), the contour area of ​​the cross section can effectively improve the uniformity of stress distribution of the cross section of the expansion joint along the horizontal direction. Of course, it is also feasible that the contour of the cross section of the connecting portion 2 along the horizontal direction is an approximately straight line shape composed of short straight line segments and / or circular arc segments connected in sequence.

[0043] In one embodiment, the connecting portion 2 is tangentially connected to the first force-bearing portion 1, thereby achieving a smooth transition and avoiding stress concentration, which can improve the overall tensile strength of the first force-bearing portion 1 and enhance local stability; in another embodiment, the connecting portion 2 is tangentially connected to the second force-bearing portion 3, thereby achieving a smooth transition and avoiding stress concentration, which can improve the overall compressive strength of the second force-bearing portion 3 and enhance local stability; in another embodiment, the connecting portion 2 is tangentially connected to both the first force-bearing portion 1 and the second force-bearing portion 3, further optimizing local stability and enhancing overall bending resistance.

[0044] In this embodiment, if Figure 1As shown, the cross section of the first stress receiving part 1 in the horizontal direction is a circular arc profile, the cross section of the second stress receiving part 3 in the horizontal direction is a circular arc profile, the radius R1 of the circular arc profile of the cross section of the first stress receiving part 1 in the horizontal direction is smaller than the radius R2 of the circular arc profile of the cross section of the second stress receiving part 3 in the horizontal direction, and the first stress receiving part 1 has a small cross section in the horizontal direction and the second stress receiving part 3 has a large cross section in the horizontal direction, forming a water drop-like structure, so that the stress of the cross section of the telescopic joint in the horizontal direction is more uniform, and the overall structural stability is improved.

[0045] In another embodiment, as shown, Figure 2 the cross section of the first stress receiving part 1 in the horizontal direction is a polygonal approximate circular arc profile, the cross section of the second stress receiving part 3 in the horizontal direction is a polygonal approximate circular arc profile, the radius R1 of the approximate circular arc profile of the cross section of the first stress receiving part 1 in the horizontal direction is smaller than the radius R2 of the approximate circular arc profile of the cross section of the second stress receiving part 3 in the horizontal direction, and the first stress receiving part 1 has a small cross section in the horizontal direction and the second stress receiving part 3 has a large cross section in the horizontal direction, forming a water drop-like structure.

[0046] The cross section of the telescopic joint in the horizontal direction has a water drop-like structure with a small top and a large bottom, which can reduce the tensile stress and compressive stress from the weight or itself, enhance the overall load bearing capacity of the telescopic assembly, and improve the structural stability and comprehensive mechanical properties.

[0047] In an embodiment, the telescopic assembly includes multiple telescopic joints and can move relatively to achieve telescopic effect. The lengths of different telescopic joints can be the same or different, which is not limited herein and can be selected appropriately according to actual conditions in application to meet the needs.

[0048] In an embodiment, the telescopic joint is integrally formed by the first stress receiving part 1, the connecting part 2 and the second stress receiving part 3 along the symmetry axis M, and has no weld.

[0049] The cross section of the first stress receiving part 1, the second stress receiving part 3 and the connecting part 2 in the horizontal direction is symmetrically formed by the common symmetry axis M, and is integrally formed to form a water drop-like structure. The cross section structure in the horizontal direction of the telescopic joint can be formed by cold drawing, hot rolling or development of a mold. For example, a mature cold rolling process is adopted, and multiple rolling programs are used to achieve the required cross section shape in the horizontal direction; or a hot rolling forming scheme is adopted, and the required cross section shape in the horizontal direction is formed by rolling according to the required thickness and shape; or a mold forming scheme is adopted, the mold is made in advance, the raw material is injected into the mold for forming, and then the corresponding treatment is performed to obtain the telescopic joint with the cross section shape in the horizontal direction.

[0050] The telescopic joint is integrally formed without welds, thus avoiding the risk of safety accidents caused by weld quality problems, extending the service life of the robotic arm and reducing after-sales maintenance costs. At the same time, it simplifies the manufacturing process of the telescopic component, giving the telescopic joint the advantages of zero bending and no cracks, greatly reducing the production and manufacturing costs of the telescopic component and improving the product's competitiveness and profit margins.

[0051] In one embodiment, the thickness of the cross-sectional profile in each extending direction is gradually transitioned;

[0052] The thickness of the first force-bearing portion 1 gradually decreases along the direction from the rear section 5 of the first force-bearing portion 1 to the front section 4 of the first force-bearing portion 1;

[0053] The thickness of the second force-bearing portion 3 gradually decreases along the direction from the rear section 7 of the second force-bearing portion 3 to the front section 6 of the second force-bearing portion 3 .

[0054] like Figure 3 As shown, in this embodiment, at the same cross section along the vertical direction, the thickness of the cross section of the telescopic joint in each extension direction is gradually transitioned. At the same cross section along the vertical direction, the tensile stress is mainly concentrated in the rear section 5 of the first force-bearing part 1. By gradually decreasing the thickness of the first force-bearing part 1 from the rear section 5 of the first force-bearing part 1 to the front section 4 of the first force-bearing part 1, the strength of the telescopic assembly is improved, and the overall lightweight and production cost reduction of the telescopic assembly are further improved. At the same cross section along the vertical direction, the compressive stress is mainly concentrated in the rear section 7 of the second force-bearing part 3. By gradually decreasing the thickness of the second force-bearing part 3 from the rear section 7 of the second force-bearing part 3 to the front section 6 of the second force-bearing part 3, the strength of the telescopic assembly is improved, and the overall lightweight and production cost reduction of the telescopic assembly are further improved.

[0055] In one embodiment, in the same cross section along the horizontal direction, the thickness T2 of at least part of the connecting portion 2 is equal to the thickness T1 of at least part of the first force-bearing portion 1; the thickness T2 of at least part of the connecting portion 2 is equal to the thickness T3 of at least part of the second force-bearing portion 3.

[0056] In this embodiment, in order to avoid stress concentration, the thickness of the connection part 2 and the first force-bearing part 1 is the same at the connection, achieving a smooth transition; the thickness of the connection part 2 and the second force-bearing part 3 is the same at the connection, achieving a smooth transition, and further improving the overall stability.

[0057] In one embodiment, in the same horizontal cross section, the thickness T1 of at least part of the first force-bearing portion 1 is different from at least one of the thickness T3 of at least part of the second force-bearing portion 3 and the thickness T2 of at least part of the connecting portion 2 .

[0058] To meet the growing demand for lightweight construction machinery, the thickness T1 of at least a portion of the first load-bearing portion 1, the thickness T3 of at least a portion of the second load-bearing portion 3, and the thickness T2 of at least a portion of the connecting portion 2 can be adjusted to be different, depending on the load conditions of the expansion joint. For example, if the first load-bearing portion 1 primarily bears tensile stress and has superior tensile strength and load-bearing capacity, its thickness T1 can be reduced. For example, if the second load-bearing portion 3 primarily bears compressive stress, its thickness T3 can be increased to ensure that the compressive stress is within a safe range. By optimizing the thickness combination of the expansion joint, the expansion joint itself can be lighter when subjected to the same load.

[0059] In one embodiment, in the same horizontal cross section, a thickness T1 of at least a portion of the first force-bearing portion 1 is smaller than a thickness T3 of at least a portion of the second force-bearing portion 3 .

[0060] In this embodiment, in the same horizontal cross-section, the thickness T1 of the first force-bearing portion 1 is less than the thickness T3 of the second force-bearing portion 3, allowing the expansion joint to achieve both mechanical performance and lightweight requirements. Because the thickness T1 of the first force-bearing portion 1 is less than the thickness T3 of the second force-bearing portion 3, to avoid stress concentration, the thickness of the connecting portion 2 at the connection with the first force-bearing portion 1 is the same, achieving a smooth transition; the thickness of the connecting portion 2 at the connection with the second force-bearing portion 3 is the same, achieving a smooth transition and further improving overall stability.

[0061] In one embodiment, the inner contour of the cross section of the telescopic joint along the horizontal direction intersects with the axis of symmetry M at the first intersection A1 and the second intersection A2, the center of curvature C of the arc-shaped contour portion of the cross section of the first force-bearing part 1 along the horizontal direction is on or near the axis of symmetry M and is located between the first intersection A1 and the midpoint B, the center of curvature D of the arc-shaped contour portion of the cross section of the second force-bearing part 3 along the horizontal direction is on or near the axis of symmetry M and is located between the second intersection A2 and the midpoint B, and the midpoint B is arranged at an equal distance from the first intersection A1 and the second intersection A2.

[0062] like Figure 1As shown, the center of curvature C of the arc-shaped profile portion of the horizontal cross-section of the first force-bearing portion 1 is on the axis of symmetry M and located between the first intersection A1 and the midpoint B, and the center of curvature D of the arc-shaped profile portion of the horizontal cross-section of the second force-bearing portion 3 is on the axis of symmetry M and located between the second intersection A2 and the midpoint B. The midpoint B is equidistant from the first intersection A1 and the second intersection A2. Of course, the center of curvature C of the arc-shaped profile portion of the horizontal cross-section of the first force-bearing portion 1 can also be near the axis of symmetry M and located between the first intersection A1 and the midpoint B, and the center of curvature D of the arc-shaped profile portion of the horizontal cross-section of the second force-bearing portion 3 can also be near the axis of symmetry M and located between the second intersection A2 and the midpoint B. This structural arrangement ensures that the center of force of the tensile load is in the area between the first intersection A1 and the midpoint B, and the center of force of the compressive load is in the area between the second intersection A2 and the midpoint B, thereby ensuring the uniformity of the stress of the entire cross-section of the expansion joint in the horizontal direction.

[0063] like Figure 2 As shown, the cross section of the first force-bearing portion 1 along the horizontal direction is an approximately circular arc profile composed of polygons, and the cross section of the second force-bearing portion 3 along the horizontal direction is an approximately circular arc profile composed of polygons. The center of curvature C of the approximately circular arc profile portion of the cross section of the first force-bearing portion 1 along the horizontal direction is on the axis of symmetry M and located between the first intersection A1 and the midpoint B. The center of curvature D of the approximately circular arc profile portion of the cross section of the second force-bearing portion 3 along the horizontal direction is on the axis of symmetry M and located between the second intersection A2 and the midpoint B. The midpoint B is equidistant from the first intersection A1 and the second intersection A2. The center of curvature C of the approximately circular arc profile portion of the cross section of the first force-bearing portion 1 along the horizontal direction may also be near the axis of symmetry M and located between the first intersection A1 and the midpoint B. The center of curvature D of the approximately circular arc profile portion of the cross section of the second force-bearing portion 3 along the horizontal direction may also be near the axis of symmetry M and located between the second intersection A2 and the midpoint B. This structural setting ensures that the force center of the tensile load is in the area between the first intersection A1 and the midpoint B, and the force center of the compressive load is in the area between the second intersection A2 and the midpoint B, ensuring the uniformity of the overall stress of the cross section of the expansion joint along the horizontal direction.

[0064] In an embodiment, the first stress receiving portion 1 comprises a first tensile stress portion 11 with at least a part of the cross section in the horizontal direction being circular arc-shaped or polygonal, and a second tensile stress portion 12 with at least a part of the cross section in the horizontal direction being circular arc-shaped or polygonal, the second tensile stress portion 12 being connected to the first tensile stress portion 11 at one end and to the connecting portion 2 at the other end, the center of curvature C of the circular arc-shaped part of the cross section in the horizontal direction of the first stress receiving portion 1 being the center of curvature C of the circular arc-shaped part of the cross section in the horizontal direction of the first tensile stress portion 11 and the circular arc-shaped part of the cross section in the horizontal direction of the second tensile stress portion 12, the average thickness t11 of the first tensile stress portion 11 being greater than the average thickness t12 of the second tensile stress portion 12.

[0065] The first tensile stress portion 11 is used to bear the main tensile stress, and the cross section in the horizontal direction of the first tensile stress portion 11 can be circular arc-shaped (as shown in Figure 1 ), the area of this cross section shape structure can reduce the tensile stress, has strong bending resistance, and can improve local stability; in another case, the cross section in the horizontal direction of the first tensile stress portion 11 is approximately circular arc-shaped composed of polygons (as shown in Figure 2 ); of course, it is also feasible that the cross section in the horizontal direction of the first tensile stress portion 11 is approximately circular arc-shaped composed of short straight line segments and / or circular arc segments connected in sequence.

[0066] The second tensile stress portion 12 is used to bear the secondary tensile stress, and the cross section in the horizontal direction of the second tensile stress portion 12 can be circular arc-shaped (as shown in Figure 1 ), the area of this cross section shape structure can reduce the tensile stress, has strong bending resistance, and can improve local stability; in another case, the cross section in the horizontal direction of the second tensile stress portion 12 is approximately circular arc-shaped composed of polygons (as shown in Figure 2 ); of course, it is also feasible that the cross section in the horizontal direction of the second tensile stress portion 12 is approximately circular arc-shaped composed of short straight line segments and / or circular arc segments connected in sequence.

[0067] The center of curvature C of the circular arc-shaped part or the approximately circular arc-shaped part of the cross section in the horizontal direction of the first stress receiving portion 1 is the center of curvature C of the circular arc-shaped part of the cross section in the horizontal direction of the first tensile stress portion 11 and the circular arc-shaped part of the cross section in the horizontal direction of the second tensile stress portion 12, and the centers of curvature are consistent, which is beneficial to local stability.

[0068] In the same cross section along the horizontal direction, the average thickness t11 of the first tensile stress portion 11 is greater than the average thickness t12 of the second tensile stress portion 12. The first tensile stress portion 11 is the area that bears the maximum tensile stress. Increasing its average thickness t11 increases the strength of the first tensile stress portion 11, avoids stress concentration and damage to the expansion joint, thereby avoiding deformation of the expansion joint and extending the service life of the expansion assembly.

[0069] In this embodiment, the thickness of the first tensile stress portion 11 is a gradual thickness. The thickness of the first tensile stress portion 11 is the largest at the first intersection A1, and gradually becomes thinner along the direction of the second tensile stress portion 12. The thickness at the connection between the first tensile stress portion 11 and the second tensile stress portion 12 is equal, achieving a smooth transition; the thickness of the second tensile stress portion 12 is a gradual thickness. The thickness gradually becomes thinner along the connection between the first tensile stress portion 11 and the second tensile stress portion 12 toward the connection portion 2. The thickness at the connection between the second tensile stress portion 12 and the connection portion 2 is equal, achieving a smooth transition, further improving the overall stability.

[0070] In one embodiment, the angle α formed by the cross section of the first tensile stress portion 11 along the horizontal direction and the symmetry axis M is in the range of 0°<α≤45°.

[0071] The range of the angle α formed by the cross section of the first tensile stress portion 11 along the horizontal direction and the symmetry axis M is 0°<α≤45°. Within this angle range, the first tensile stress portion 11 bears the main tensile stress.

[0072] In one embodiment, the second force-bearing portion 3 includes a first compressive stress portion 31, at least part of which has a circular arc or polygonal profile in the horizontal cross-section, and a second compressive stress portion 32, at least part of which has a circular arc or polygonal profile in the horizontal cross-section. One end of the second compressive stress portion 32 is connected to the first compressive stress portion 31, and the other end is connected to the connecting portion 2. The center of curvature D of the circular arc profile portion of the cross-section of the second force-bearing portion 3 along the horizontal direction is the center of curvature D of the circular arc profile portion of the cross-section of the first compressive stress portion 31 along the horizontal direction and the center of curvature D of the circular arc profile portion of the cross-section of the second compressive stress portion 32 along the horizontal direction. The average thickness t31 of the first compressive stress portion 31 is greater than the average thickness t32 of the second compressive stress portion 32.

[0073] The first compressive stress portion 31 is used to bear the main compressive stress. The cross-section of the first compressive stress portion 31 along the horizontal direction may be in the shape of an arc (e.g. Figure 1 As shown), the area of ​​the cross-sectional shape structure can reduce the compressive stress, has strong bending resistance, and can improve local stability; in another case, the profile of the cross section of the first compressive stress portion 31 along the horizontal direction is an approximately circular arc composed of polygons (as shown Figure 2As shown); Of course, it is also feasible that the profile of the cross section of the first compressive stress portion 31 along the horizontal direction is an approximately arc shape composed of short straight line segments and / or arc segments connected in sequence.

[0074] The second compressive stress portion 32 is used to bear the secondary compressive stress. The cross-section of the second compressive stress portion 32 along the horizontal direction may be in the shape of an arc (e.g. Figure 1 As shown), the cross-sectional shape structure area can reduce the compressive stress, has strong bending resistance, and can improve local stability; in another case, the cross-sectional profile of the second compressive stress portion 32 along the horizontal direction is an approximately circular arc composed of polygons (as shown Figure 2 As shown); Of course, it is also feasible that the profile of the cross section of the second compressive stress portion 32 along the horizontal direction is an approximately circular arc shape composed of short straight line segments and / or circular arc segments connected in sequence.

[0075] The center of curvature D of the arc-shaped profile or the approximately arc-shaped profile portion of the cross-section of the second force-bearing portion 3 along the horizontal direction is the center of curvature D of the arc-shaped profile or the approximately arc-shaped profile portion of the cross-section of the first compressive stress portion 31 and the second compressive stress portion 32 along the horizontal direction. The centers of curvature remain consistent, which is beneficial to local stability.

[0076] In the same horizontal cross-section, the average thickness t31 of the first compressive stress portion 31 is greater than the average thickness t32 of the second compressive stress portion 32. The first compressive stress portion 31 is the area subject to the greatest compressive stress. Increasing the average thickness t31 increases the strength of the first compressive stress portion 31, preventing stress concentration from damaging the expansion joint and, in turn, deformation of the expansion joint, thereby extending the service life of the expansion assembly.

[0077] In this embodiment, the thickness of the first compressive stress portion 31 is a gradual thickness. The thickness of the first compressive stress portion 31 is the largest at the second intersection A2, and gradually becomes thinner along the direction of the second compressive stress portion 32. The thickness at the connection between the first compressive stress portion 31 and the second compressive stress portion 32 is equal, achieving a smooth transition; the thickness of the second compressive stress portion 32 is a gradual thickness. The thickness gradually becomes thinner along the connection between the first compressive stress portion 31 and the second compressive stress portion 32 toward the connection portion 2. The thickness at the connection between the second compressive stress portion 32 and the connection portion 2 is equal, achieving a smooth transition, further improving the overall stability.

[0078] In one embodiment, in the same cross-section along the horizontal direction, the average thickness t31 of the first compressive stress portion 31 is greater than the average thickness t11 of the first tensile stress portion 11; in another embodiment, in the same cross-section along the horizontal direction, the average thickness t31 of the first compressive stress portion 31 is less than the average thickness t11 of the first tensile stress portion 11; in another embodiment, in the same cross-section along the horizontal direction, the average thickness t31 of the first compressive stress portion 31 is equal to the average thickness t11 of the first tensile stress portion 11.

[0079] The average thickness t31 of the first compressive stress part 31 and the average thickness t11 of the first tensile stress part 11 can be optimized and combined according to actual needs, so that the telescopic joint realizes the light weight and the reduction of production cost of the telescopic joint while meeting the strength requirement of comprehensive mechanical properties.

[0080] In an embodiment, the angle β formed by the cross section of the first compressive stress part 31 along the horizontal direction and the symmetry axis M is in the range of 0°<β≤45°.

[0081] The angle β formed by the cross section of the first compressive stress part 31 along the horizontal direction and the symmetry axis M is in the range of 0°<β≤45°, and the first compressive stress part 31 in this angle range bears the main compressive stress.

[0082] The embodiment of another aspect of the present application also provides a mechanical arm comprising a telescopic assembly.

[0083] The mechanical arm comprises a telescopic assembly, and the telescopic assembly comprises multiple telescopic joints, and different telescopic joints are connected in a sleeved manner. The telescopic joint without welding can greatly reduce the problem of welding protrusion caused by welding, and further make the cross-sectional size attenuation between adjacent telescopic joints smaller. In the case of consistent mechanical arm external dimensions, the cross-sectional size of the innermost telescopic joint is larger, and the carrying capacity is better.

[0084] The mechanical arm can be applied to cranes, log grabbers, forklifts, crawler cranes, aerial work trucks, aerial work platforms, etc., without limitation.

[0085] The embodiment of another aspect of the present application also provides a support leg comprising a telescopic assembly, which is installed upside down on the telescopic assembly of the support leg.

[0086] The telescopic assembly can be used for the support leg, because the stress of the support leg is opposite to that of the mechanical arm, and therefore the telescopic assembly is installed upside down. The support leg can be applied to cranes, log grabbers, forklifts, crawler cranes, aerial work trucks, aerial work platforms, etc., without limitation.

[0087] The embodiment of another aspect of the present application also provides a construction machine comprising a chassis and a mechanical arm and a support leg, and the mechanical arm and the support leg are located on the chassis. Such a construction machine not only realizes the light weight and the reduction of production cost, but also improves the safety and the construction efficiency.

[0088] The above is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A telescopic assembly for a load, characterized in that: The telescopic assembly comprises at least one telescopic section which is a hollow shell and includes: A first force-bearing portion (1), the first force-bearing portion (1) being located above the cross section, and having at least a portion of the cross section along the horizontal direction having an arc shape or a polygonal shape approximately in the shape of an arc; A second force-bearing portion (3), the second force-bearing portion (3) being located below the cross section, and having at least a portion of the cross section along the horizontal direction having an arc shape or a polygonal shape approximately in the shape of an arc; and a connecting portion (2) connected between the first force-bearing portion (1) and the second force-bearing portion (3), wherein at least a portion of a cross-section of the connecting portion (2) along the horizontal direction is linear; The cross sections of the first force-bearing portion (1), the second force-bearing portion (3) and the connecting portion (2) along the horizontal direction are all axially symmetrical and have a common axis of symmetry (M), and the radius R1 of the contour portion of the cross section of the first force-bearing portion (1) along the horizontal direction, which is at least approximately in the shape of a circular arc, is smaller than the radius R2 of the contour portion of the cross section of the second force-bearing portion (3) along the horizontal direction, which is at least approximately in the shape of a circular arc.

2. The telescopic assembly according to claim 1, characterized in that The telescopic joint is formed integrally from the first force-bearing portion (1), the connecting portion (2) and the second force-bearing portion (3) along the symmetry axis (M), and has no weld seams as a whole.

3. The telescopic assembly according to claim 1, characterized in that The thickness of the cross-section in each extending direction is gradually transitioned; The thickness of the first force-bearing portion (1) gradually decreases along the direction from the rear section (5) of the first force-bearing portion (1) to the front section (4) of the first force-bearing portion (1); The thickness of the second force-bearing portion (3) gradually decreases along the direction from the rear section (7) of the second force-bearing portion (3) to the front section (6) of the second force-bearing portion (3).

4. The telescopic assembly according to claim 1, wherein: In the same cross section along the horizontal direction, the thickness T1 of at least a portion of the first force-bearing portion (1) is smaller than the thickness T3 of at least a portion of the second force-bearing portion (3).

5. The telescopic assembly according to claim 1, wherein: The inner contour of the cross section of the telescopic joint in the horizontal direction intersects with the symmetry axis (M) at the first intersection point (A1) and the second intersection point (A2); the center of curvature C of the arc-shaped contour portion of the cross section of the first force-bearing portion (1) in the horizontal direction is on or near the symmetry axis (M) and is located between the first intersection point (A1) and the midpoint (B); the center of curvature D of the arc-shaped contour portion of the cross section of the second force-bearing portion (3) in the horizontal direction is on or near the symmetry axis (M) and is located between the second intersection point (A2) and the midpoint (B); the midpoint (B) is arranged at an equal distance from the first intersection point (A1) and the second intersection point (A2).

6. The telescopic assembly according to claim 5, characterized in that The first force-bearing portion (1) comprises a first tensile stress portion (11) having at least a partial contour of a cross section in the horizontal direction in the shape of an arc or a polygon, and a second tensile stress portion (12) having at least a partial contour of a cross section in the horizontal direction in the shape of an arc or a polygon, one end of the second tensile stress portion (12) being connected to the first tensile stress portion (11) and the other end being connected to the connecting portion (2), a center of curvature C of the arc-shaped contour portion of the cross section in the horizontal direction of the first force-bearing portion (1) being the center of curvature C of the arc-shaped contour portion of the cross section in the horizontal direction of the first tensile stress portion (11) and the arc-shaped contour portion of the cross section in the horizontal direction of the second tensile stress portion (12), and an average thickness t11 of the first tensile stress portion (11) being greater than an average thickness t12 of the second tensile stress portion (12).

7. The telescopic assembly according to claim 5, characterized in that The second force-bearing portion (3) comprises a first compressive stress portion (31) having at least a partial contour of a cross section in the horizontal direction that is arc-shaped or polygonal, and a second compressive stress portion (32) having at least a partial contour of a cross section in the horizontal direction that is arc-shaped or polygonal, one end of the second compressive stress portion (32) being connected to the first compressive stress portion (31) and the other end being connected to the connecting portion (2), a center of curvature D of the arc-shaped contour portion of the cross section in the horizontal direction of the second force-bearing portion (3) being the center of curvature D of the arc-shaped contour portion of the cross section in the horizontal direction of the first compressive stress portion (31) and the arc-shaped contour portion of the cross section in the horizontal direction of the second compressive stress portion (32), and an average thickness t31 of the first compressive stress portion (31) being greater than an average thickness t32 of the second compressive stress portion (32).

8. A robotic arm, characterized in that: Comprising the telescopic assembly according to any one of claims 1 to 7.

9. A support leg, characterized in that: The telescopic assembly comprises the telescopic assembly according to any one of claims 1 to 7, wherein the telescopic assembly for the leg is installed upside down.

10. A construction machine, characterized in that: It comprises a chassis, a mechanical arm as claimed in claim 8 and a support leg as claimed in claim 9, wherein the mechanical arm and the support leg are located on the chassis.

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