Shaft sleeve mounting structure, arm section, folding boom and mechanical apparatus having same

Abstract

The present invention relates to the field of mechanical equipment. Disclosed are a shaft sleeve mounting structure, an arm section, a folding boom, and a mechanical apparatus having same. The shaft sleeve mounting structure is used for pivotally connecting a first part to a second part, and comprises: a first shaft sleeve (1) and a second shaft sleeve (2) which are mounted to the first part at intervals, and a shaft sleeve attachment plate (3) which connects the first shaft sleeve (1) and the second shaft sleeve (2) and which is attached to the surface of the first part, such that the second part is allowed to be pivotally connected to the first part by means of a pivot shaft passing through the first shaft sleeve (1), and, driven by a driving assembly pivotally connected to the second shaft sleeve (2), the first part pivots relative to the second part. The shaft sleeve mounting structure can significantly reduce the variation range and load magnitude in the load direction of shaft holes, effectively improve the bearing state of the shaft holes, and is particularly suitable for preventing booms of fiber composite materials from crushing and cracking towards weak portions at shaft hole positions of booms.

Description

Bushing mounting structure, arm section, folding boom and mechanical equipment with same

[0001] Cross-reference to Related Applications

[0002] This application claims the benefit of Chinese Patent Application No. 202411301164.8, filed September 18, 2024, the contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to a mechanical equipment, such as a construction machine, and in particular to a bushing mounting structure for pivotally connecting a first component to a second component. Furthermore, the present application also relates to an arm section and a folding boom, and a mechanical equipment with the folding boom. BACKGROUND

[0004] In various types of mechanical equipment, such as construction machines, fire-fighting equipment, etc., it is common to pivotally connect different components to each other by means of cooperating pivot shafts and bushings, and to drive one of the components to rotate relative to the other component to which it is pivotally connected by means of a driving unit, such as a hydraulic cylinder, to achieve the purpose of construction or operation, such as material transportation. Typically, as an important component in a construction machine, such as a concrete pump truck, a folding boom comprises a plurality of arm sections pivotally connected to each other by means of pivot shafts, and an arm cylinder is connected between adjacent arm sections to enable the adjacent arm sections to be driven to pivot relative to each other by means of the arm cylinder, so as to facilitate the transportation of concrete to a predetermined position by means of a delivery pipe.

[0005] In view of the development goal of lightweight arm boom, the prior art proposes a solution of manufacturing the arm boom body by means of fiber composite material. Compared with the steel material (including high-strength steel) of the traditional arm boom, the fiber composite material has the advantages of high specific strength, high specific modulus, good fatigue resistance, good damage safety, good damping vibration reduction performance, and strong designability, etc., which makes it achieve remarkable results in the lightweight design and manufacturing of the arm boom.

[0006] However, the use of fiber composite material to manufacture the arm boom will cause new problems. For example, due to the anisotropy of the fiber composite material, when the posture of the arm boom changes with the working condition, the direction and size of the shaft hole load change greatly at the same time, which easily causes the weak direction of the fiber composite material to be crushed and cracked. For another example, the fiber composite material also has the problems of poor wear resistance and inability to be welded with the metal bushing, etc. When the posture of the arm boom changes with the working condition, the bushing rotates with the pivot shaft in the arm boom shaft hole, which causes the shaft hole to be worn and the hole diameter to become larger and larger, so that the connection between the bushing and the shaft hole is loosened, which affects the service life of the arm boom. SUMMARY

[0007] The present application aims to overcome the problem that the existing technology is prone to crushing and cracking of the arm support at the shaft hole position due to the large change in the size and direction of the arm support shaft hole load with the change in the arm support posture, and to provide a shaft sleeve mounting structure, an arm segment and a folding arm support for the arm support, which can significantly reduce the change range of the arm support shaft hole load direction and the load size when the arm support posture changes with the working condition, thereby significantly improving the bearing state of the arm support shaft hole.

[0008] To achieve the above-mentioned object, the present application provides a shaft sleeve mounting structure for pivotally connecting a first component to a second component, which comprises a first shaft sleeve and a second shaft sleeve spaced apart from each other and mounted to the first component, and a shaft sleeve plate connected to the first shaft sleeve and the second shaft sleeve and attached to the surface of the first component, so as to allow the second component to be pivotally connected to the first component through a pivot shaft passing through the first shaft sleeve, and to enable the first component to be driven to pivot relative to the second component by a driving assembly pivotally connected to the second shaft sleeve.

[0009] Preferably, the first component is a box-shaped structure, and the first shaft sleeve and the second shaft sleeve extend through the side walls of the box-shaped structure and are respectively connected to the shaft sleeve plates attached to the wall surfaces of the side walls.

[0010] Preferably, the first shaft sleeve and the second shaft sleeve respectively have a peripheral surface of a revolution body or a non-revolution body, and the first component is formed with shaft holes in interference fit with the peripheral surfaces.

[0011] Preferably, the first component has a main body made of a fiber composite material, and the first shaft sleeve, the second shaft sleeve and the shaft sleeve plate are made of a metal material.

[0012] Preferably, a metal lining plate is embedded in the position of the first component for mounting the first shaft sleeve and the second shaft sleeve.

[0013] The second aspect of the present application provides an arm segment having a first shaft sleeve for pivotally connecting to an adjacent arm segment and a second shaft sleeve for drivingly connecting to an arm support oil cylinder, and a shaft sleeve plate attached to the surface of the side wall of the arm segment and connected between the first shaft sleeve and the second shaft sleeve.

[0014] Preferably, the arm segment has a main body made of a fiber composite material, and the first shaft sleeve, the second shaft sleeve and the shaft sleeve plate are made of a metal material.

[0015] Preferably, the first shaft sleeve, the second shaft sleeve and the shaft sleeve plate are made of carbon steel, alloy steel, aluminum alloy, magnesium alloy or titanium alloy, and / or the shaft sleeve plate is formed with weight-reducing holes.

[0016] The third aspect of the present application provides a folding boom, comprising a first arm section and a second arm section pivotally connected to each other, and a driving assembly connected between the first arm section and the second arm section, the first arm section having a first shaft sleeve and a second shaft sleeve mounted at a distance from each other, the second arm section having a pivot shaft passing through the first shaft sleeve, the driving assembly being pivotally connected to the second shaft sleeve to drive the first arm section to pivot about the pivot shaft relative to the second arm section, wherein a shaft sleeve lining plate is connected between the first shaft sleeve and the second shaft sleeve and abuts against a side wall surface of the first arm section.

[0017] Preferably, the first arm section and the second arm section each have a main body made of fiber composite material, and the first shaft sleeve, the second shaft sleeve and the shaft sleeve lining plate are made of metal material.

[0018] Preferably, the driving assembly comprises a boom cylinder and a first connecting rod each pivotally mounted to the second arm section, and a second connecting rod pivotally connected to the second shaft sleeve, the boom cylinder and the second connecting rod each being hingedly connected to the first connecting rod.

[0019] The fourth aspect of the present application provides a mechanical equipment having the above-mentioned shaft sleeve mounting structure or folding boom.

[0020] Through the above technical solution, the shaft sleeve mounting structure, the arm section and the folding boom of the present application connect the first shaft sleeve for pivotally connecting adjacent components (arm sections) and the second shaft sleeve for pivotally connecting the driving assembly (boom cylinder) into one through the shaft sleeve lining plate, and the load borne by any one of the first shaft sleeve and the second shaft sleeve from the corresponding pivot shaft is associated with the other, so that the two groups of shaft holes mounting the first shaft sleeve and the second shaft sleeve jointly bear the load transmitted by the pivot shaft, thereby improving the bearing state of the shaft hole. Tests prove that, in the case of being applied to the folding boom, when the posture of the boom changes, the shaft sleeve mounting structure and the arm section provided by the present application can significantly reduce the change range and the load size of the load direction of the boom shaft hole, thereby significantly improving the bearing state of the boom shaft hole. This can effectively prevent the crushing and cracking in the weak direction for the fiber composite material boom, thereby significantly reducing the risk of damage to the boom structure due to the anisotropy of the fiber composite material, and is beneficial to the development and application of the lightweight technology of the boom. BRIEF DESCRIPTION OF DRAWINGS

[0021] Fig. 1 is a partial view of an arm section according to a preferred embodiment of the present application, wherein the shaft sleeve mounting structure provided by the present application is included;

[0022] Fig. 2 is a cross section of a fiber composite material boom;

[0023] Fig. 3 is a sectional view of the shaft sleeve mounting structure in Fig. 1;

[0024] Figure 4 is a partial view of a prior art boom, including bushings that are independent of each other;

[0025] Figure 5 is a schematic diagram showing the boom posture of a folding boom, wherein there is an inter-boom angle between the first boom section and the second boom section;

[0026] Figure 6 is a schematic diagram of a coordinate system used to represent the load direction of the boom shaft hole;

[0027] Figure 7 shows the relationship curve between boom posture and boom shaft hole load direction;

[0028] Figure 8 shows the relationship curve between boom posture and boom shaft hole load;

[0029] Figure 9 is a perspective view of the welded components of the bushing and the bushing plate;

[0030] Figure 10 is a cross-sectional view of the welded component in Figure 9. Detailed Implementation

[0031] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0032] As for the foregoing, one aspect of the present invention provides a bushing mounting structure for pivotally connecting a first component to a second component, and other aspects of the present invention provide a boom, a folding boom, and mechanical equipment including the bushing mounting structure or the folding boom. It should be understood that although this document primarily uses a folding boom as an example to illustrate the implementation and technical effects of the provided bushing mounting structure, the bushing mounting structure can be used to pivotally connect other different components besides the boom. Therefore, the first component and the second component described in this invention can not only be the first and second boom sections in the folding boom described later, but also other components in various types of mechanical equipment that are pivotally connected and can be driven to pivot relative to each other. In this case, the mechanical equipment described in this invention can be of the type of construction machinery, fire-fighting equipment, such as concrete pump trucks and aerial ladder trucks.

[0033] Referring to Figs. 1 to 3, a sleeve mounting structure for pivotally connecting a first component to a second component according to a preferred embodiment of the present application comprises a first sleeve 1 and a second sleeve 2 mounted to the first component at a distance from each other, and a sleeve plate 3 connecting the first sleeve 1 and the second sleeve 2 and adhering to a surface of the first component. In combination with Fig. 5, the first component and the second component can be a first arm segment 4 and a second arm segment 5 adjacent to each other in a folding arm, wherein the first arm segment 4 and the second arm segment 5 can be pivotally connected to each other at a first pivot connection point a where the first sleeve 1 is mounted, and a second pivot connection point b where the second sleeve 2 is mounted can be used for pivotally connecting a driving assembly which can drive the first arm segment 4 to pivot relative to the second arm segment 5 to present different arm postures. The sleeve plate 3 can adhere to a surface of the first arm segment 4, and when the first arm segment 4 is configured as a box-type arm, the inner and outer walls of the first arm segment 4 can respectively have the sleeve plate 3 connected to the first sleeve 1 and the second sleeve 2.

[0034] Thus, by the above sleeve mounting structure, the second component can be pivotally connected to the first component by a pivot shaft passing through the first sleeve 1, and the first component can be driven to pivot relative to the second component by the driving assembly pivotally connected to the second sleeve 2. Since the sleeve mounting structure connects the first sleeve 1 for pivotally connecting the adjacent component (the second component, the second arm segment 5) and the second sleeve 2 for pivotally connecting the driving assembly (arm cylinder) into one through the sleeve plate 3, the load from the corresponding pivot shaft borne by either of the first sleeve 1 and the second sleeve 2 is associated with the other, so that the two sets of shaft holes mounting the first sleeve 1 and the second sleeve 2 jointly bear the load transmitted by the pivot shaft, thereby improving the bearing state of the shaft holes. In contrast, in the prior art as shown in Fig. 4, the two sets of arm shaft holes of the arm segment are independent of each other, and the arm shaft hole at the first pivot connection point a and the first sleeve 1 and the second sleeve 2 mounted therein, and the arm shaft hole at the second pivot connection point b and the second sleeve 2 mounted therein, each independently bear the load transmitted by the pivot shaft. When the arm posture changes, the arm shaft hole load size and direction will change greatly, which is easy to cause the arm to be crushed and cracked at the shaft hole position, especially for the fiber composite arm, since the fiber composite material has anisotropy, it has a weak direction with lower bearing capacity. The sleeve mounting structure of the present application effectively improves the bearing state of the shaft hole through the sleeve plate.

[0035] For the shaft sleeve mounting structure provided by the present application shown in Figure 1 and the prior art shown in Figure 4, the inventors test and compare the load direction and load size of the arm support shaft hole under different arm postures based on the folding arm post model shown in Figure 5. Specifically, modeling is performed by using simulation calculation software Abaqus, and the size and direction of the arm support shaft hole support force at the first pivot connection point a and the first pivot connection point b are extracted. The angle between the first arm section 4 and the second arm section 5 is the inter-arm angle α, which is used to represent the arm posture; and the coordinate system shown in Figure 6 is used as the reference coordinate system for representing the arm support shaft hole load direction. The specific test process is as follows:

[0036] A grid model is constructed by selecting a pump truck with a size of 1:1, in which the arm post, connecting rod, pin shaft (pivot shaft) and shaft sleeve are meshed by using shell element, solid element and beam element respectively. The assembly relationship between the pin shaft and the arm post and connecting rod is modeled by using hard contact and sliding friction contact properties. The load of the most severe load condition of the actual vehicle is extracted, and the input load of the simulation calculation is determined after multiplying the dynamic load coefficient, which includes the concentrated force and bending moment formed by the wind load, the concentrated force, bending moment and torque formed by the self-weight of the front end structure. The calculation is submitted, and the hinge hole force size and direction of the arm post hinge hole are output in the result file. Similarly, the size and direction of the arm post hinge hole force under different postures can be obtained by adjusting the arm post posture (inter-arm angle).

[0037] The test results are shown in Figures 7 and 8. When the inter-arm angle α changes from 30° to 240°, using the existing shaft sleeve mounting structure shown in Figure 4, the arm support shaft hole load direction (i.e. the hinge hole force direction shown in Figure 7) at the first pivot connection point a changes from 172.7° to 283.4°, with a change range of 110.7°, and the arm support shaft hole load size (i.e. the hinge hole force shown in Figure 8) changes in the range of 113.3 tons to 210.6 tons; under the same working condition (the same test condition and motion range), using the shaft sleeve mounting structure provided by the present application, the arm support shaft hole load direction at the first pivot connection point a changes from 224.6° to 252.8°, with a change range of 28.2°, and the arm support shaft hole load size changes in the range of 113 tons to 121.9 tons. As can be seen, when the arm post posture changes, the shaft sleeve mounting structure provided by the present application changes the bearing mode of the arm support shaft hole, which can significantly reduce the change range of the arm support shaft hole load direction and the load size, thereby significantly improving the bearing state of the arm support shaft hole. This can effectively prevent the crushing and cracking of the fiber composite arm post in the weak direction, thereby significantly reducing the risk of damage to the arm post structure due to the anisotropy of the fiber composite material, and is conducive to the development and application of arm post lightweight technology.

[0038] With reference to Figs. 1-3, the present application provides an arm section, here the first arm section 4, having a first boss 1 for pivotal connection to an adjacent arm section (e.g. the second arm section 5) and a second boss 2 for transmission connection to an arm cylinder, and a boss plate 3 being connected between the first boss 1 and the second boss 2 and being attached to the side wall surface of the arm section. It should be understood that the arm cylinder is usually transmission connected to the second boss 2 through a connecting rod, which will be described in detail later in the description of the folding arm support. As the aforementioned boss mounting structure, the arm section as a specific implementation form of the boss mounting structure has the same technical effects, which will not be described here again.

[0039] With reference to Figs. 1-3 and 5, the present application further provides a folding arm support, wherein Fig. 5 only schematically shows two arm sections in the folding arm support, i.e. the first arm section 4 and the second arm section 5, which are pivotally connected to each other at a first pivotal connection point a and are connected with a drive assembly therebetween. The first arm section 4 has a first boss 1 and a second boss 2 being spaced apart from each other, the second arm section 5 has a pivotal shaft passing through the first boss 1, and the drive assembly is pivotally connected to the second boss 2 to be able to drive the first arm section 4 to pivot about the pivotal shaft relative to the second arm section 5, and wherein the first boss 1 and the second boss 2 are connected with a boss plate 3 being attached to the side wall surface of the first arm section 4. As known from the foregoing, the folding arm support can change the arm support hole load direction and load size within a relatively small range in different arm support postures, thereby significantly improving the load bearing state of the arm support hole.

[0040] During operation, the load borne by the arm support mainly comes from the gravity of the front end structure, which can be decomposed into a first component force along the direction parallel to the line connecting the first pivotal connection point a and the first pivotal connection point b and a second component force perpendicular to the first component force, etc. For the boss mounting structure of the prior art, the magnitude and direction of the force borne by the arm support hole at the first pivotal connection point a and the first pivotal connection point b will change greatly within the range of the inter-arm included angle required by the operation specification; while using the boss mounting structure provided by the present application, the component forces borne by the first boss 1 and the second boss 2 along the direction of their connecting line can be cancelled out by the boss plate, so that the arm support hole at the first pivotal connection point a and the first pivotal connection point b mainly bears the component force perpendicular to the direction, and the magnitude and direction of the component force will only change within a relatively small range when the inter-arm included angle changes, especially the magnitude of the force can basically remain constant, thereby the load bearing state is significantly improved.

[0041] As aforementioned, the first component and the second component to be pivotally connected by the shaft sleeve mounting structure of the present application can be components in various mechanical equipment which are pivotally connected and can be driven to relatively pivot. As shown in FIG. 2 and FIG. 3, the first component and the second component can be adjacent arm sections of a concrete pump truck boom or the like box structure having a hollow cavity formed by side walls, wherein the first shaft sleeve 1 and the second shaft sleeve 2 extend through the side walls of the box structure and are respectively connected with shaft sleeve attaching plates 3 attached to the wall surfaces of the side walls on both sides of the side walls. Moreover, the shaft holes (and the shaft sleeves mounted thereon) on the two opposite side walls are aligned with each other so that the pivot shaft is pivotally connected by passing through the shaft sleeves on the two side walls.

[0042] In the shaft sleeve mounting structure, the arm section and the folding boom described above, the first component, the first arm section 4, to which the shaft sleeve mounting structure is mounted can have a main body made of fiber composite material, and the second component, the second arm section 5, pivotally connected therewith can also have a main body made of fiber composite material, so that the corresponding functional module (such as a boom) can be lightened, and the first shaft sleeve 1, the second shaft sleeve 2 and the shaft sleeve attaching plate 3 can be made of metal material so as to be connected as a whole by welding or the like. For example, the first shaft sleeve 1, the second shaft sleeve 2 and the shaft sleeve attaching plate 3 can be made of carbon steel, alloy steel, aluminum alloy, magnesium alloy or titanium alloy, and preferably alloy steel. As shown in FIG. 2 and FIG. 3, the arm section can have a composite material layer 41 made of fiber composite material, and a metal lining plate 42 is embedded in the position for mounting the first shaft sleeve 1 and the second shaft sleeve 2 so as to bear relatively large compressive stress at this position.

[0043] It can be understood that although the shaft sleeve mounting structure of the present application is advantageous for solving the problem that the boom structure is easily damaged due to the anisotropy of fiber composite material, the shaft sleeve mounting structure does not exclude its use in a boom or other pivotally connected component made of conventional material.

[0044] In the manufacturing process, first, the fiber composite boom can be positioned by marking, and the arm section shaft hole is formed at the position of the fiber composite boom shaft hole by machining methods such as spiral milling, etc. for shaft sleeve mounting. Referring to FIG. 9 and FIG. 10, the first shaft sleeve 1, the second shaft sleeve 2 and the shaft sleeve attaching plate 3 are cut by methods such as flame cutting, laser cutting, etc. to obtain a blank; then, the first shaft sleeve 1, the second shaft sleeve 2 and the shaft sleeve attaching plate 3 are machined by machining methods such as turning, milling, etc.; further, the first shaft sleeve 1 and the second shaft sleeve 2 are welded to one of the shaft sleeve attaching plates 3 to form a welded piece of the shaft sleeve and the shaft sleeve attaching plate; then, the welded piece can be finished to obtain a shaft sleeve structure suitable for being mounted to the arm section shaft hole and making the shaft sleeve attaching plate 3 attached to the surface of the arm section.

[0045] In a preferred embodiment of the present application, the first shaft sleeve 1 and the second shaft sleeve 2 can respectively have a peripheral surface of a revolution or a peripheral surface of a non-revolution, such as a cross section of a circular shape, an elliptical shape, a waist-round shape, a polygonal shape, etc., and the first component or the first arm segment 4 can be formed with a shaft hole corresponding thereto, and the two can be assembled together by interference fit. Since the first shaft sleeve 1 and the second shaft sleeve 2 are connected together by the shaft sleeve paste plate 3, in the installed state, the shaft sleeves can also be prevented from rotating in the shaft hole, thereby preventing the shaft hole from being worn and significantly improving the service life. Thus, the peripheral surfaces of the first shaft sleeve 1 and the second shaft sleeve 2 and the shaft hole for mounting them can be formed as a circumferential surface, without having to be formed as a special shape with a cross section of a polygonal shape, etc.

[0046] The first shaft sleeve 1 and the second shaft sleeve 2 can be fixedly connected to the shaft sleeve paste plate 3 by welding, riveting, etc., as shown in FIG. 3, for example, the first shaft sleeve 1 and the second shaft sleeve 2 are connected to the shaft sleeve paste plate 3 on both sides by welding, and a weld 32 is formed. The shaft sleeve paste plate 3 can have an elliptical shape, a dumbbell shape, etc., and the outer ring can be determined according to design needs. The middle part of the shaft sleeve paste plate 3 can be formed with a weight-reducing hole 31.

[0047] Referring to FIG. 5, as a typical application, the driving assembly for pivotally connecting the second shaft sleeve 2 can have a first connecting rod 7 and a second connecting rod 8 connected in transmission between the arm cylinder 6 and the second shaft sleeve 2, and the first connecting rod 7 can be provided with multiple hinge points. Specifically, the driving assembly includes an arm cylinder 6 and a first connecting rod 7 pivotally mounted to the second arm segment 5 and a second connecting rod 8 pivotally connected to the second shaft sleeve 2, wherein the arm cylinder 6 and the second connecting rod 8 are respectively hinged to the first connecting rod 7. Thus, when the arm cylinder 6 is retracted, it can apply a pulling force to the first arm segment 4 at the second pivot connection point b through the first connecting rod 7 and the second connecting rod 8, so that the first arm segment 4 rotates relative to the second arm segment 5 about the first pivot connection point a.

[0048] The folding arm provided by the present application not only can improve the bearing state of the shaft hole of the fiber composite arm, reduce the bearing load of the shaft hole of the fiber composite arm, solve the problems of easy crushing and cracking of the shaft hole, but also can solve the problems of easy rotation of the shaft sleeve of the fiber composite arm and easy wear of the shaft hole, and significantly improve the service life of the shaft hole of the fiber composite arm.

[0049] Another aspect of the present application also provides a mechanical equipment having the above-mentioned shaft sleeve mounting structure or a folding arm, which can be an arm of a concrete pump truck or a high-altitude fire truck, etc.

[0050] The preferred embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that various specific technical features are combined in any suitable manner. In order to avoid unnecessary repetition, the present application does not further describe various possible combination manners. However, these simple modifications and combinations should also be regarded as disclosed by the present application, and all fall within the protection scope of the present application.

Claims

1. A bushing mounting structure for pivotally connecting a first member to a second member, characterized by, The shaft sleeve mounting structure comprises a first shaft sleeve (1) and a second shaft sleeve (2) which are spaced apart and mounted to the first component, and a shaft sleeve plate (3) which connects the first shaft sleeve (1) and the second shaft sleeve (2) and is attached to the surface of the first component, so as to allow the second component to be pivotally connected to the first component by a pivot shaft passing through the first shaft sleeve (1) and enable the first component to be driven to pivot relative to the second component by a driving assembly which is pivotally connected to the second shaft sleeve (2).

2. The bush mounting structure according to claim 1, characterized by The first component is in a box type structure, and the first shaft sleeve (1) and the second shaft sleeve (2) extend through the side wall of the box type structure and are respectively connected to the shaft sleeve plate (3) which is attached to the surface of the side wall.

3. The bush mounting structure according to claim 1, wherein The first shaft sleeve (1) and the second shaft sleeve (2) respectively have a peripheral surface of a revolving body or a non-revolving body, and the first component is formed with shaft holes which are in interference fit with the peripheral surfaces.

4. The bush mounting structure according to claim 1, wherein The first component has a main body made of a fiber composite material, and the first shaft sleeve (1), the second shaft sleeve (2) and the shaft sleeve plate (3) are made of a metal material.

5. The bush mounting structure according to claim 1, wherein The first component is provided with a metal lining plate (42) which is embedded in the position for mounting the first shaft sleeve (1) and the second shaft sleeve (2).

6. An arm segment, characterized in that The arm link has a first shaft sleeve (1) for pivotally connecting to an adjacent arm link and a second shaft sleeve (2) for drivingly connecting to an arm support oil cylinder, and a shaft sleeve plate (3) which is attached to the surface of the side wall of the arm link is connected between the first shaft sleeve (1) and the second shaft sleeve (2).

7. The arm segment of claim 6, wherein, The arm link has a main body made of a fiber composite material, and the first shaft sleeve (1), the second shaft sleeve (2) and the shaft sleeve plate (3) are made of a metal material.

8. The arm segment of claim 6, wherein, The first shaft sleeve (1), the second shaft sleeve (2) and the shaft sleeve plate (3) are made of carbon steel, alloy steel, aluminum alloy, magnesium alloy or titanium alloy, and / or the shaft sleeve plate (3) is provided with a weight-reducing hole (31).

9. A folding jib comprising a first jib section (4) and a second jib section (5) pivotally connected to each other and a drive assembly connected between the first jib section (4) and the second jib section (5), characterized in that The first arm link (4) has a first shaft sleeve (1) and a second shaft sleeve (2) which are spaced apart and mounted, the second arm link (5) has a pivot shaft passing through the first shaft sleeve (1), and a driving assembly is pivotally connected to the second shaft sleeve (2) to drive the first arm link (4) to pivot relative to the second arm link (5) about the pivot shaft, wherein a shaft sleeve plate (3) which is attached to the surface of the side wall of the first arm link (4) is connected between the first shaft sleeve (1) and the second shaft sleeve (2).

10. The folding boom of claim 9, wherein, The first arm link (4) and the second arm link (5) respectively have a main body made of a fiber composite material, and the first shaft sleeve (1), the second shaft sleeve (2) and the shaft sleeve plate (3) are made of a metal material.

11. The folding boom of claim 9, wherein, The driving assembly comprises an arm support oil cylinder (6) and a first connecting rod (7) which are pivotally mounted to the second arm link (5), and a second connecting rod (8) which is pivotally connected to the second shaft sleeve (2), and the arm support oil cylinder (6) and the second connecting rod (8) are respectively hinged to the first connecting rod (7).

12. A mechanical rig, characterized by The machine is equipped with a shaft sleeve mounting structure according to any one of claims 1 to 5 or a folding jib according to any one of claims 9 to 11.

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