A large loader front frame ball hinge shaft ear plate assembly tool and assembly method

Abstract

The application provides a large loader front frame ball hinge shaft ear plate assembly tool, which comprises a base, Y-shaped iron, a positioning assembly, a clamping assembly, an ear plate clamping device and a pressing plate assembly, the base is installed on a platform, two Y-shaped irons are installed on the base, and a set of positioning assemblies and clamping assemblies are installed on the outer sides of the two Y-shaped irons; a ball hinge shaft is horizontally placed on the two Y-shaped irons, the outer circles of the long barrels at both ends of the ball hinge shaft are respectively located on the outer sides of the two Y-shaped irons, the long barrels are fixed with the Y-shaped irons through the pressing plate assembly, and an ear plate is installed at the outer circle at each end of the long barrel. After the large loader ball hinge shaft ear plate is hot-mounted, the first step bottom edge is clamped by the clamping assembly, the second step bottom edge is tightly attached to the upper surface of the positioning assembly, the positions of the two ear plates are accurately positioned, the consistency of the positions of the ear plates at both ends of the ball hinge shaft is ensured, and the problem of ear plate installation out of position is avoided.

Description

Technical Field

[0001] This invention belongs to the field of assembly technology, and in particular relates to an assembly tooling and assembly method for a ball joint shaft lug plate of a large loader front frame. Background Technology

[0002] The ball joint shaft assembly is a key load-bearing component of the front frame of a large heavy-duty loader, used to mount the loader's lifting arm and the lifting arm's hydraulic lifting device. The ball joint shaft is a long shaft with a ball head mounted at each end of a long cylinder. Two lugs need to be interference-fitted onto the outer circumference of each end of the long cylinder near the ball heads, and the outer contours of the two lugs must be aligned after installation. Because the lugs are interference-fitted to the outer circumference of the ball joint shaft's long cylinder, installation requires heat treatment. During installation, the fitter must quickly install and fix the lugs to the ball joint shaft; otherwise, the lugs may seize up midway, resulting in incomplete installation. A crucial factor affecting installation speed during heat treatment is ensuring the relative positions of the lugs at both ends are aligned, guaranteeing that the outer contours of the lugs on both sides are consistent.

[0003] The conventional method for installing lugs involves marking lug position lines on the outer circumference of both ends of the ball joint shaft's long cylinder, and also marking corresponding positions on the two lugs. During heat installation, the lugs at both ends are fitted onto the mating outer circumference of the ball joint shaft, and the lugs are adjusted so that the markings on the lugs align with the markings on the outer circumference of the ball joint shaft. This installation method is laborious in aligning the lugs with the outer circumference of the ball joint shaft, has poor positional accuracy, and is prone to causing the lugs to be improperly installed and "seize." Summary of the Invention

[0004] To address the problems existing in the prior art, this invention aims to propose an assembly fixture and method for the ball joint shaft lug plate of a large loader front frame. This lug plate assembly fixture solves the problems of the conventional installation method, which involves aligning the lug plate with the outer circle of the ball joint shaft with considerable effort, poor positional accuracy, and the lug plate being easily misinstalled and "locked up".

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] A ball joint shaft lug assembly fixture for a large loader front frame includes a base, Y-shaped irons, a positioning assembly, a clamping assembly, a lug clamping device, and a pressure plate assembly. The base is mounted on a platform, and two Y-shaped irons are mounted on the base. A set of positioning and clamping assemblies mounted on the base are provided on the outer sides of each of the two Y-shaped irons. A ball joint shaft is horizontally placed on the two Y-shaped irons. The outer circles of the two ends of the long cylinder of the ball joint shaft are respectively located on the outer sides of the two Y-shaped irons. The long cylinder is fixed to the Y-shaped irons by the pressure plate assembly, and a lug is installed at the outer circles of the two ends of the long cylinder.

[0007] Each ear plate has a stepped bottom, divided into a first step bottom edge and a second step bottom edge. The positioning component is located between the second step bottom edge of the ear plate and the base. The clamping component is located between the first step bottom edge of the ear plate and the base. The lifting clamping component causes the second step bottom edge to abut against the positioning component. The two ear plates are pressed against the outer circular shoulder surfaces at both ends of the long cylinder by the ear plate clamping device.

[0008] Furthermore, the positioning component includes a positioning support, which is mounted on the base.

[0009] Furthermore, the vertical distance between the upper surface of the positioning support and the center of the inscribed circle of the upper part of the Y-shaped iron is equal to the vertical distance from the center of the largest specification ball joint shaft to the bottom edge of the second step.

[0010] Furthermore, the positioning component also includes a positioning block, which is mounted on the positioning support. The upper surface of the positioning block contacts the bottom edge of the second step. The height of the positioning block is equal to the vertical distance between the bottom edge of the second step of the ear plate and the surface of the positioning support after the ear plate and ball joint shaft to be installed are placed on the Y-shaped iron.

[0011] Furthermore, the ear plate clamping device includes a round pull rod, two pressure caps and two clamping nuts. The two ends of the round pull rod pass through the two ends of the ball joint shaft, and each end passes through a pressure cap and is threadedly connected to a clamping nut, so that the pressure cap abuts against the outer side of the ear plate.

[0012] Furthermore, the pressure cap includes a cross beam and a clamping rod, with a clamping rod installed at each of the four ends of the cross beam for clamping the lugs.

[0013] Furthermore, the pressure plate assembly includes a pressure plate, a double-ended stud, and a pressure plate nut. The pressure plate contacts the upper surface of the ball joint shaft, and both ends of the pressure plate are provided with U-shaped grooves. One end of the double-ended stud is connected to a T-shaped nut in the T-shaped groove of the platform, and the other end passes through the U-shaped groove and is connected to the pressure plate nut.

[0014] A method for assembling the ball joint lug plate of the front frame of a large loader includes:

[0015] S1. Fix the ball hinge lug assembly fixture onto the platform;

[0016] S2. Place the ball joint shaft to be installed on the two Y-shaped irons, so that the outer circles of both ends of the long cylinder of the ball joint shaft to be installed are located outside the two Y-shaped irons, and fix the ball joint shaft to be installed by the pressure plate assembly.

[0017] S3. After heating one side of the ear plate, install it onto the outer circle of one side of the long cylinder and make the ear plate close to the shoulder surface. Then rotate the ear plate so that the bottom edge of the second step of the ear plate is in contact with the upper surface of the positioning block. Then lift the clamping assembly so that the bottom edge of the second step is in contact with the upper surface of the positioning block.

[0018] S4. Press the ear plate firmly against the ball joint shaft using the ear plate clamping device;

[0019] S5. After the side ear plate has cooled to room temperature, repeat steps S3-S5 to heat-fit the other side ear plate of the long tube.

[0020] Furthermore, in step S2, when the size of the ball joint shaft to be installed is smaller than that of the ball joint shaft, the ear plate to be installed and the ball joint shaft are placed on the Y-shaped iron. The height of the positioning block is determined according to the vertical distance between the bottom edge of the second step of the ear plate and the surface of the positioning support, and the positioning block is installed on the positioning support.

[0021] Furthermore, in step S3, the ear plate is heated to 220-230℃ using an electric heating furnace, with a heating rate of 50℃ / h and a holding time of no less than 2 hours. Before removing it from the furnace, the inner hole size of the ear plate is measured to ensure it meets the requirements for heat fitting gap.

[0022] Compared with existing technologies, the assembly fixture and assembly method for the ball joint shaft lug plate of the front frame of a large loader described in this invention have the following advantages:

[0023] (1) The ball hinge shaft ear plate assembly fixture of the large loader front frame described in this invention achieves the height positioning of the ball hinge shaft by placing the ball hinge shaft on two Y-shaped irons; after the ear plate is hot-installed, the bottom edge of the first step is pressed by the clamping component, so that the bottom edge of the second step is in close contact with the upper surface of the positioning component, thereby achieving accurate positioning of the two ear plate positions and ensuring the consistency of the ear plate positions at both ends of the ball hinge shaft, avoiding the problem of "locking up" due to improper installation of the ear plate.

[0024] (2) The assembly method of ball joint shaft ear plate of large loader front frame described in this invention does not require marking lines on the ear plate and the outer circle of the ball joint shaft. The height and position of the positioning support and positioning block are designed according to the vertical distance from the center of the ball joint shaft to the bottom edge of the second step of the ear plate. After the ear plate is hot-installed, the bottom edge of the second step is tightly attached to the surface of the positioning block, so as to achieve accurate positioning of the two ear plate positions, speed up the installation speed, and avoid the ear plate "locking up" during the installation and failing to be installed in place. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 This is a schematic diagram of the assembly of the ball joint lug plate provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of a Y-shaped iron structure provided in an embodiment of the present invention;

[0028] Figure 3This is a schematic diagram of the base structure provided in an embodiment of the present invention;

[0029] Figure 4 This is a front view of the ball joint lug plate assembly provided in an embodiment of the present invention;

[0030] Figure 5 This is a side view of the ball joint lug plate assembly provided in an embodiment of the present invention;

[0031] Figure 6 for Figure 5 Cross-sectional view of the middle section (BB);

[0032] Figure 7 for Figure 1 Enlarged view of part A in the middle;

[0033] Figure 8 This is a schematic diagram of the pressure plate assembly structure provided in an embodiment of the present invention;

[0034] Figure 9 A schematic diagram of the ball joint shaft to be installed;

[0035] Figure 10 A schematic diagram of the ball joint shaft for mounting the ear plate.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. Base; 11. Base plate; 2. Y-shaped iron; 21. Rib plate one; 22. Rib plate two; 23. Reinforcing plate; 24. Mounting block; 3. Positioning assembly; 31. Positioning support; 32. Positioning block; 4. Tightening assembly; 5. Ear plate clamping device; 51. Round tie rod; 52. Pressure cap; 521. Cross beam; 522. Tightening rod; 523. Reinforcing rib; 53. Clamping nut; 6. Pressure plate assembly; 61. Pressure plate; 62. Double-ended stud; 63. Pressure plate nut; 7. Platform; 8. Ball joint shaft; 9. Ear plate; 91. Bottom edge of the first step; 92. Bottom edge of the second step; C. Ball joint shaft mounting ear plate part; D. Shoulder surface. Detailed Implementation

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0039] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0040] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] like Figures 1 to 10 As shown, a ball joint shaft lug plate assembly fixture for a large loader front frame includes a base 1, a Y-shaped iron 2, a positioning component 3, a clamping component 4, a lug plate clamping device 5, and a pressure plate component 6. The base 1 is mounted on a platform 7, and two Y-shaped irons 2 are mounted on the base 1. A set of positioning components 3 and clamping components 4 mounted on the base 1 are provided on the outer side of each of the two Y-shaped irons 2.

[0043] A ball joint shaft 8 is horizontally placed on the two Y-shaped irons 2. The outer circles of the two ends of the long cylinder of the ball joint shaft 8 are respectively located outside the two Y-shaped irons 2. The long cylinder is fixed to the Y-shaped irons 2 by the pressure plate assembly 6. An ear plate 9 is installed at the outer circles of the two ends of the long cylinder.

[0044] Each ear plate 9 has a stepped bottom, divided into a first step bottom edge 91 and a second step bottom edge 92. The positioning component 3 is located between the second step bottom edge 92 of the ear plate and the base 1. The clamping component 4 is located between the first step bottom edge 91 of the ear plate and the base 1. The lifting clamping component 4 causes the second step bottom edge 92 to abut against the positioning component 3. The two ear plates 9 are pressed against the outer circles of both ends of the long cylinder by the ear plate clamping device 5.

[0045] The front frame ball joint shaft lug assembly fixture of the present invention achieves height positioning of the ball joint shaft by placing the ball joint shaft on two Y-shaped irons 2; after the lug is heat-installed, the bottom edge 91 of the first step is pressed by the clamping component 4, so that the bottom edge 92 of the second step is tightly attached to the upper surface of the positioning component 3, thereby achieving accurate positioning of the two lug positions and ensuring the consistency of the lug positions at both ends of the ball joint shaft, avoiding the problem of "locking" due to improper installation of the lug.

[0046] In a preferred embodiment of the present invention, the base 1 is welded from multiple square tubes, and a base plate 11 is welded to each of the four corners of the bottom of the base 1. The flatness tolerance of the two ends of each base plate 11 is 0.02mm.

[0047] In actual use, the base 1 is welded from multiple square tubes, which makes it easy to move and has low manufacturing cost.

[0048] In a preferred embodiment of the present invention, stiffening plate 1 21 and stiffening plate 22 are welded between the two Y-shaped irons 2, and the bottom edge of stiffening plate 1 21 is welded to the base 1; a reinforcing plate 23 is welded to the outside of each Y-shaped iron 2, and the bottom edge of the reinforcing plate 23 is welded to the base 1; the Y-shaped iron 2 is provided with a mounting block 24 for lifting.

[0049] In actual use, the two Y-shaped irons 2 are welded to the base 1.

[0050] In a preferred embodiment of the present invention, the positioning component 3 includes a positioning support 31 and the positioning support 31 is mounted on the base 1.

[0051] In actual use, the positioning support 31 is welded to the base 1, and the surface roughness Ra of the upper surface is not greater than 3.2.

[0052] In a preferred embodiment of the present invention, the vertical distance between the center of the inscribed circle of the upper part of the Y-shaped iron 2 and the upper surface of the positioning support 31 is equal to the vertical distance from the center of the largest specification ball joint shaft to the bottom edge 92 of the second step.

[0053] In actual use, the dimensions of the upper part of the Y-shaped iron 2 are designed according to the outer circle dimensions of both ends of the ball joint shaft. The inclined steel plate surfaces of the upper parts of the two Y-shaped iron 2 are respectively machined to Ra3.2, and the distance dimensional accuracy between the center of the inner circle of the largest specification ball joint shaft and the Y-shaped iron 2 and the machined surface on the base positioning support 31 is controlled with a tolerance of 0.1mm.

[0054] In a preferred embodiment of the present invention, the positioning component 3 further includes a positioning block 32, which is mounted on the positioning support 31. The upper surface of the positioning block 32 contacts the bottom edge 92 of the second step. The height of the positioning block 32 is equal to the vertical distance between the second bottom edge 92 of the ear plate and the surface of the positioning support 31 when the ear plate and the ball joint shaft assembly to be installed are placed on the Y-shaped iron.

[0055] In actual use, the positioning block 32 is engaged on the positioning support 31, and the parallelism tolerance of the upper and lower surfaces of the positioning block 32 is 0.02mm; select the ball joint shaft with the largest specification among the ball joint shafts to be installed, and design the vertical distance between the positioning support 31 and the center of the inscribed circle of the upper part of the Y-shaped iron 2 based on the vertical distance from the center of the largest specification ball joint shaft to the bottom edge 92 of the second step.

[0056] For other ball joint shafts smaller than the maximum size, the second step bottom edge 92 of the ball joint shaft of different sizes is made to fit with the positioning block 32 by replacing the positioning block 32 of different heights on the positioning support 31; each size of ball joint shaft assembly is designed with a positioning block of a corresponding thickness to adapt to the distance from the center of the ball joint shaft of different sizes to the second step bottom edge 92, reducing the number of times the positioning support 31 is replaced; in this embodiment, the vertical distance from the center of each size of ball joint shaft to the second step bottom edge 92 of the ear plate ranges from 369.9 to 658.9 mm.

[0057] In a preferred embodiment of the present invention, the clamping component 4 is preferably a jack.

[0058] In actual use, by using a jack to lift the bottom edge 91 of the first step, the bottom edge 92 of the second step is made to fit tightly against the upper surface of the positioning component 3, thus achieving accurate positioning of the two ear plates. Using the jack is convenient and quick.

[0059] In a preferred embodiment of the present invention, the ear plate clamping device 5 includes a round pull rod 51, two pressure caps 52 and two clamping nuts 53. The two ends of the round pull rod 51 pass through the two ends of the ball joint shaft 8, and each end passes through a pressure cap 52 and is threadedly connected to a clamping nut 53, so that the pressure cap 52 abuts against the outer side of the ear plate 9.

[0060] In actual use, after the ear plates at both ends of the ball joint shaft are hot-installed, the clamping device 5 tightens the clamping nuts 53 at both ends to press the cover 52 against the outside of the ear plate, thereby pressing the ear plate against the outer circular shoulder surface at both ends of the long cylinder, and preventing gaps from forming between the ear plate and the outer circular shoulder surface at both ends of the ball joint shaft long cylinder after cooling.

[0061] In a preferred embodiment of the present invention, the pressure cap 52 includes a cross beam 521 and a tightening rod 522, and a tightening rod 522 for tightening the lug 9 is respectively installed at each end of the cross beam 521.

[0062] In actual use, the cross beam 521 and the top clamping rod 522 are equipped with reinforcing ribs 523 to strengthen the connection; when tightening the clamping nuts 53 at both ends, one end of the top clamping rod 522 abuts against the ear plate 9, so that the ear plate 9 is pressed against the outer circular shoulders at both ends of the long cylinder.

[0063] In a preferred embodiment of the present invention, the pressure plate assembly 6 includes a pressure plate 61, a double-ended stud 62, and a pressure plate nut 63. The pressure plate 61 is in contact with the upper surface of the ball joint shaft 8, and both ends of the pressure plate 61 are provided with U-shaped grooves. One end of the double-ended stud 62 is connected to the T-shaped nut in the T-shaped groove of the platform 7, and the other end passes through the U-shaped groove and is connected to the pressure plate nut 63.

[0064] In practical use, one end of the double-ended stud 62 is connected to the T-nut in the T-slot of the platform 7, and the other end is passed through the U-slot and tightened with the pressure plate nut 63 to fix it to the pressure plate 61, so that the ball joint shaft is pressed against the Y-shaped iron 2. The base 1 and the platform 7 can also be fixed by the pressure plate assembly. The length of the double-ended stud 62 and the size of the pressure plate 61 are selected according to actual needs.

[0065] The double-ended stud 62 can be moved within the U-shaped groove during installation. Select a suitable position according to the size of the ball joint shaft, and fix it with the pressure plate nut 63.

[0066] A method for assembling the ball joint lug plate of the front frame of a large loader includes:

[0067] S1. Fix the ball hinge lug assembly fixture onto platform 7;

[0068] S2. Place the ball joint shaft to be installed on the two Y-shaped irons 2, so that the outer circles of the two ends of the long cylinder of the ball joint shaft to be installed are located outside the two Y-shaped irons 2, and fix the ball joint shaft to be installed by the pressure plate assembly 6.

[0069] S3. Heat one side ear plate 9 and install it onto the outer circle of one side of the long cylinder, making the ear plate fit tightly against the shoulder surface;

[0070] Then rotate the ear plate 9 so that the bottom edge 92 of the second step of the ear plate fits against the upper surface of the positioning block 32, and then lift and tighten the clamping assembly 4 so that the bottom edge 92 of the second step is pressed against the upper surface of the positioning block 32.

[0071] S4. Press the ear plate 9 firmly against the ball joint shaft using the ear plate clamping device 4.

[0072] S5. After the side ear plate has cooled to room temperature, repeat steps S3-S4 to heat-fit the other side ear plate of the long tube.

[0073] In step S2, when the size of the ball joint shaft to be installed is smaller than that of the largest ball joint shaft, the ear plate and the ball joint shaft to be installed are placed on the Y-shaped iron. The height of the positioning block 32 is determined according to the vertical distance between the bottom edge of the second step of the ear plate and the surface of the positioning support 31, and the positioning block 32 is installed on the positioning support 31.

[0074] Before installing the ear plate 9 in step S3, heat both ear plates to 220-230℃ using an electric heating furnace, set the heating rate to 50℃ / h, and keep them warm for no less than 2 hours. Before removing them from the furnace, measure the inner hole size of the ear plate to see if it meets the requirements for the hot fitting gap.

[0075] Assembly steps for the ball joint shaft lug plate of the front frame of a large loader:

[0076] (1) Hoist the front frame ball joint shaft lug assembly fixture onto the platform 7 and fix it onto the platform 7 by a set of pressure plate assemblies 6 (the size is designed according to the base 1) and press it tight;

[0077] (2) Select a suitable positioning block 32 and install it on the positioning support 31, and secure it firmly;

[0078] (3) Hang the ball joint shaft that needs to be installed on the ear plate on the Y-shaped iron 2, adjust the axial position of the ball joint shaft so that the outer circles of both ends of the ball joint shaft are evenly exposed on the Y-shaped iron 2, and use another set of pressure plate assembly 6 (the size is designed according to the ball joint shaft) to press the ball joint shaft and the Y-shaped iron 2 firmly.

[0079] (4) Heat the left and right ear plates to 220-230℃ using an electric heating furnace at a heating rate of 50℃ / h and keep them warm for no less than 2 hours. Before taking them out of the furnace, measure the inner hole size of the ear plates to see if they meet the requirements for the hot fitting gap.

[0080] (5) Hang one side of the ear plate (the other side continues to be placed in the furnace for heat preservation) and install it into the corresponding outer circle position of the ball hinge shaft and make the ear plate close to the shoulder surface. Then rotate the ear plate so that the bottom edge 92 of the second step of the ear plate fits against the upper surface of the positioning block 32. Use a jack to push the bottom edge 91 of the first step of the ear plate. After it is close, use the ear plate clamping device 5 to press the ear plate and the shoulder of the ball hinge shaft firmly.

[0081] (6) After the side ear plate has cooled to room temperature, heat install the other side ear plate according to step (5).

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A tooling for assembling the ball joint shaft lug plate of a large loader front frame, characterized in that: The device includes a base (1), Y-shaped irons (2), positioning components (3), clamping components (4), ear plate clamping devices (5), and pressure plate components (6). The base (1) is mounted on a platform (7). Two Y-shaped irons (2) are mounted on the base (1). A set of positioning components (3) and clamping components (4) mounted on the base (1) are provided on the outer side of each of the two Y-shaped irons (2). A ball joint shaft (8) is placed horizontally on the two Y-shaped irons (2). The outer circles of the two ends of the long cylinder of the ball joint shaft (8) are located on the outer side of the two Y-shaped irons (2). The long cylinder is fixed to the Y-shaped irons (2) by the pressure plate components (6). An ear plate (9) is installed on the outer circle of each end of the long cylinder. Each ear plate (9) has a stepped bottom, divided into a first step bottom edge (91) and a second step bottom edge (92). The positioning component (3) is located between the second step bottom edge (92) of the ear plate (9) and the base (1). The clamping component (4) is located between the first step bottom edge (91) of the ear plate (9) and the base (1). The lifting clamping component (4) makes the second step bottom edge (92) abut against the positioning component (3). The two ear plates (9) are pressed against the outer circular shoulder surfaces at both ends of the long cylinder by the ear plate clamping device (5). The positioning component (3) includes a positioning support (31), which is mounted on the base (1); The vertical distance between the upper surface of the positioning support (31) and the center of the inscribed circle of the upper part of the Y-shaped iron (2) is equal to the vertical distance from the center of the largest specification ball joint shaft (8) to the bottom edge (92) of the second step; The positioning component (3) further includes a positioning block (32), which is installed on the positioning support (31). The upper surface of the positioning block (32) is in contact with the bottom edge (92) of the second step. The height of the positioning block (32) is equal to the vertical distance between the bottom edge (92) of the second step of the ear plate and the surface of the positioning support (31) after the ear plate and the ball joint shaft to be installed are placed on the Y-shaped iron (2). The ear plate clamping device (5) includes a round pull rod (51), two pressure caps (52) and two clamping nuts (53). The two ends of the round pull rod (51) pass through the two ends of the ball joint shaft (8), and each end passes through a pressure cap (52) and is threaded to a clamping nut (53) so that the pressure cap (52) abuts against the outside of the ear plate (9). The pressure cap (52) includes a cross beam (521) and a clamping rod (522), and a clamping rod (522) is installed at each of the four ends of the cross beam (521) for clamping the ear plate (9).

2. The assembly fixture for the ball joint shaft lug plate of the front frame of a large loader according to claim 1, characterized in that: The pressure plate assembly (6) includes a pressure plate (61), a double-ended stud (62), and a pressure plate nut (63). The pressure plate (61) is in contact with the upper surface of the ball joint shaft (8). Both ends of the pressure plate (61) are provided with U-shaped grooves. One end of the double-ended stud (62) is connected to the T-shaped nut in the T-shaped groove of the platform (7), and the other end passes through the U-shaped groove and is connected to the pressure plate nut (63).

3. A method for assembling the ball joint lug plate of the front frame of a large loader, characterized in that: The assembly fixture for the ball joint shaft lug plate of the front frame of a large loader as described in any one of claims 1-2 includes: S1. Fix the ball hinge lug assembly fixture onto the platform (7); S2. Place the ball joint shaft to be installed on two Y-shaped irons (2), so that the outer circles of both ends of the long cylinder of the ball joint shaft to be installed are outside the two Y-shaped irons (2), and fix the ball joint shaft to be installed by the pressure plate assembly (6). S3. After heating one side of the ear plate, install it on the outer circle of the long cylinder and make the ear plate close to the shoulder surface. Then rotate the ear plate so that the bottom edge of the second step of the ear plate is in contact with the upper surface of the positioning block (32). Then lift the clamping assembly (4) so ​​that the bottom edge of the second step is in contact with the upper surface of the positioning block (32). S4. Press the ear plate firmly against the ball joint shaft to be installed using the ear plate clamping device (5); S5. After the side ear plate has cooled to room temperature, repeat steps S3-S4 to heat-fit the other side ear plate of the long tube.

4. The assembly method of the ball joint shaft lug plate of the front frame of a large loader according to claim 3, characterized in that: In step S2, when the size of the ball joint shaft to be installed is smaller than that of the largest ball joint shaft, the ear plate and the ball joint shaft to be installed are placed on the Y-shaped iron (2). The height of the positioning block (32) is determined according to the vertical distance between the bottom edge of the second step of the ear plate and the surface of the positioning support (31), and the positioning block (32) is installed on the positioning support (31).

5. The assembly method of the ball joint shaft lug plate of the front frame of a large loader according to claim 3, characterized in that: In step S3, the ear plate is heated to 220-230℃ in an electric heating furnace, with a heating rate of 50℃ / h and a holding time of no less than 2 hours. Before removing it from the furnace, the inner hole size of the ear plate is measured to see if it meets the requirements for heat fitting gap.

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