A high-precision assembly method for a large-size cylinder block and an inner cylinder

Abstract

A high-precision assembly method for a large-size cylinder block and an inner cylinder, including the first step of inspecting the workpiece dimensions, the second step of machining the lifting ring screw holes, the third step of cleaning the cylinder block, the fourth step of hoisting the cylinder block, the fifth step of supporting the inner cylinder, the sixth step of heating the cylinder block, and the seventh step of sleeving the workpiece. During the assembly process, the cylinder block is heated to 390 to 400 °C and kept warm for four hours to expand the cylinder block. After the heat preservation ends, the operator measures the inner hole diameter of the cylinder block with a T-square to determine the passability between the cylinder block and the inner cylinder. At the same time, the levelness of the cylinder block is adjusted by the three-point positioning method, and the levelness of the inner cylinder end face is ensured by adjusting the height of each support block, indirectly ensuring the coaxiality of the cylinder block and the inner cylinder. This design can not only ensure the levelness of the cylinder block and the inner cylinder respectively, so that the central axes of the cylinder block and the inner cylinder are parallel, but also measure whether the expansion amount of the cylinder block meets the requirements with a T-square, avoiding the difficulty in assembly caused by the interference fit between the cylinder block and the inner cylinder.

Description

Technical Field

[0001] The present invention relates to an assembly method, and particularly to a high-precision assembly method for a large-sized cylinder block and an inner cylinder. Background Art

[0002] The cylinder barrel is an important part of a hydraulic cylinder. The cylinder barrel and the piston cooperate to form an actuator of the hydraulic cylinder, which is used to convert hydraulic energy into mechanical energy. For a large-sized hydraulic cylinder, in order to ensure that the cylinder barrel simultaneously meets the requirements of strength, wear resistance, and also takes into account characteristics such as electrical conductivity and magnetic conductivity, its cylinder barrel is usually composed of a cylinder block and an inner cylinder made of different materials. The cylinder block is generally made of steel, and the inner cylinder is generally made of copper.

[0003] The cylinder block and the inner cylinder need to be separately processed and then assembled together to form a complete cylinder barrel. The assembly methods include directly using the mechanical press-fitting method and the cold shrinking method. Although both of these methods can sleeve the cylinder block on the inner cylinder to form a cylinder barrel, they still have the following defects:

[0004] 1. In order to ensure firm connection, an interference fit is required between the cylinder block and the inner cylinder. When using the mechanical press-fitting method, due to the influence of stress, the inner cylinder may be scratched, deformed or even damaged. At the same time, the cylinder barrel press-fitting machine is only suitable for the assembly of cylinder barrels with smaller sizes. For large-sized cylinder barrels, when using the mechanical press-fitting method, a large-sized press-fitting machine needs to be customized, which has a high cost, a long preparation period, a narrow application range and a low degree of flexibility, and thus cannot be widely used.

[0005] 2. When using the cold shrinking method to assemble the cylinder block and the inner cylinder, due to the limitation of material properties, especially for large-sized parts, the cooling equipment requires a relatively large space and has a low cooling efficiency. If the coaxiality between the cylinder block and the inner cylinder cannot be guaranteed during the shrinking process, the cylinder block and the inner cylinder will be stuck.

[0006] 3. For large-sized cylinder barrels with a diameter greater than one meter and relatively high precision requirements, due to their large diameter, it is difficult to ensure that the forces on each part of the end face are consistent during press-fitting. Not only are the existing assembly methods difficult to ensure the assembly precision, but also it is easy to cause deformation of the components.

[0007] 4. When the ratio of the length to the diameter of the cylinder barrel is small, it is difficult for the operator to find the central axis through the outer contour of the cylinder barrel, which increases the positioning difficulty between the cylinder block and the inner cylinder.

[0008] Disclosing the information of this background art section is only intended to enhance the overall understanding of the present application, and should not be construed as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0009] The object of the present invention is to overcome the disadvantages in the prior art that are likely to cause damage to the cylinder barrel and difficult to ensure the assembly accuracy, and to provide a high-precision assembly method for a large-sized cylinder block and an inner cylinder that can assemble the cylinder block and the inner cylinder through a shrink-fit assembly process while ensuring the assembly accuracy.

[0010] To achieve the above object, the technical solution of the present invention is:

[0011] A high-precision assembly method for a large-sized cylinder block and an inner cylinder, the assembly method is used to assemble the cylinder block and the inner cylinder, the cylinder block is sleeved on the inner cylinder, the diameters of the cylinder block and the inner cylinder are greater than one meter, the lengths of the cylinder block and the inner cylinder are greater than three meters, the cylinder block is of a cylindrical structure, both ends of the cylinder block are flange end faces, the inner wall of the cylinder block and the outer wall of the inner cylinder are in interference fit, the inner cylinder is of a cylindrical structure, a top thimble plate of the inner cylinder is detachably and fixedly arranged at the top end of the inner cylinder, a clamping plate of the inner cylinder is detachably and fixedly arranged at the bottom end of the inner cylinder, and a flange is arranged at the bottom end of the outer wall of the inner cylinder;

[0012] The assembly method includes:

[0013] The first step: Check the workpiece dimensions. Place the produced cylinder block and inner cylinder on the inspection table, and check whether the outer dimensions of the cylinder block and the inner cylinder meet the requirements of the drawing through measuring tools. If the outer dimensions do not meet the requirements of the drawing, the parts with non-conforming outer dimensions shall enter the repair process. If they meet the requirements of the drawing, proceed to the second step of machining the lifting ring screw holes;

[0014] The second step: Machine the lifting ring screw holes. Place the inspected cylinder block on the machining table, and machine three groups of lifting ring screw holes on the flange end face at the top of the cylinder block through a drill press. When the machining of the lifting ring screw holes is completed, proceed to the third step of cleaning the workpiece;

[0015] The third step: Clean the cylinder block. Check whether there are machining defects such as burrs and chamfers inside and outside the cylinder block. If there are machining defects, remove them with a hand file. If there are no machining defects, clean the cylinder block with acetone and dry it. When the cylinder block is dry, proceed to the fourth step of lifting the workpiece;

[0016] The fourth step: Lift the cylinder block. Install a lifting ring in each of the three groups of lifting ring screw holes on the cylinder block. Install one end of the three groups of lifting tools and steel wire ropes into the three lifting rings on the cylinder block respectively. At the same time, make marks on the lifting rings and the corresponding steel wire ropes with high-temperature grade paint. Fix the other ends of the three groups of lifting tools and steel wire ropes to the crane. When the installation of the three groups of lifting tools is completed, the operator starts the crane to lift the cylinder block. When the cylinder block leaves the ground, the operator adjusts the length of the steel wire ropes through the three groups of lifting tools to make the end face of the cylinder block horizontal. At this time, proceed to the fifth step of supporting the inner cylinder;

[0017] Step 5: Support the inner cylinder. Place the inner cylinder vertically on the support flat plate. When the inner cylinder is placed on the support flat plate, the end of the inner cylinder near the inner cylinder clamping plate faces the support flat plate. The support flat plate is arranged on the ground through a plurality of height-adjustable support blocks. After the inner cylinder is placed, the operator measures the levelness of the inner cylinder end face with a level and adjusts the height of each support block so that the levelness of the inner cylinder end face is less than or equal to 0.5 mm. After the levelness of the inner cylinder end face meets the requirements, proceed to Step 6: Heating the cylinder block;

[0018] Step 6: Heating the cylinder block. Set a plurality of cushion blocks at the bottom of the heating furnace cavity. Each cushion block faces the bottom of the cylinder block. After the cushion blocks are set, the operator controls the crane to start working, so that the cylinder block enters the cavity of the heating furnace and vertically drops onto each cushion block. After the weight of the cylinder block is fully supported by the cushion blocks, disassemble each set of lifting tools and wire ropes. After each set of lifting tools and wire ropes are disassembled, the operator closes the cavity of the heating furnace and starts the heating furnace until the temperature in the heating furnace cavity reaches 390°C to 400°C and keeps it warm for 4 hours. After the heat preservation ends, the operator measures the inner hole diameter of the cylinder block with a T-shaped ruler. When the difference between the inner hole diameter of the cylinder block after heating and the inner hole diameter before heating meets the expansion amount requirement, proceed to Step 7: Assembling the workpiece;

[0019] Step 7: Assembling the workpiece. According to the marks in Step 4: Lifting the cylinder block, install one end of each of the three sets of lifting tools and wire ropes into the corresponding lifting rings on the cylinder block that has been heated and meets the expansion amount requirement, fix the other ends of the three sets of lifting tools and wire ropes to the crane, and start the crane to lift the cylinder block to directly above the inner cylinder placed on the support flat plate. When the cylinder block reaches directly above the inner cylinder, set an engineering double ladder on each side of the cylinder block. Two observers make their observation positions higher than the top of the cylinder block through the engineering double ladder. At this time, the two observers detect the inner diameter of the cylinder block with a T-shaped ruler and measure the temperature of the cylinder block with a high-temperature infrared spot thermometer at the same time. When the inner diameters at all parts of the cylinder block meet the expansion amount requirement and the cylinder block is greater than or equal to 210°C, the operator starts the crane to lower the cylinder block and sleuth it on the inner cylinder. During the process of the cylinder block descending, manually fine-tune the lifting tool to keep the gap between the inner wall of the cylinder block and the outer wall of the inner cylinder uniform. When the cylinder block descends until the bottom of the cylinder block touches the top of the flange at the bottom end of the inner cylinder, the assembly of the cylinder block and the inner cylinder is completed.

[0020] In the step of machining the lifting ring screw holes in Step 2, the three sets of lifting ring screw holes are evenly distributed on the flange end face at one end of the cylinder block corresponding to the top end of the inner cylinder. Each set of lifting ring screw holes includes two M24 threaded holes. The lifting ring screws in the step of lifting the cylinder block in Step 4 are M24 lifting rings.

[0021] In the step of lifting the cylinder block in Step 4, the lifting tool is a hoist with an adjustable wire rope length.

[0022] The supporting flat plate is of a flat plate structure. A plurality of supporting blocks are evenly distributed between the outer edge of the bottom of the supporting flat plate and the ground. The supporting block includes an L-shaped bottom plate, a wedge block and an adjusting bolt. The L-shaped bottom plate includes a horizontal plate and a vertical plate which are perpendicularly connected to each other. The wedge block is arranged on the top of the horizontal plate, and the vertical end of the wedge block is arranged close to the vertical plate. A threaded hole matching with the adjusting bolt is formed in the vertical plate, and the threaded rod of the adjusting bolt is arranged close to the wedge block.

[0023] The T-shaped ruler includes a measuring rod, a connecting rod, a handle, a double-headed bolt and two measuring mushroom heads. An internal threaded hole is formed at each end of the measuring rod. Screws matching with the internal threaded holes are arranged at the bottoms of the two measuring mushroom heads. The two measuring mushroom heads are respectively fixedly connected to the internal threaded holes formed at the two ends of the measuring rod through the screws arranged thereon. The distance between the ends of the two measuring mushroom heads is equal to the designed inner diameter of the cylinder block. The middle of the measuring rod is fixedly connected to one end of the connecting rod. The measuring rod and the connecting rod are perpendicular to each other. The other end of the connecting rod is fixedly connected to the handle through the double-headed bolt.

[0024] In the step of the first inspection of the workpiece size, the designed inner diameter of the cylinder block is millimeters, the designed outer diameter of the inner cylinder is millimeters. In the step of the sixth heating of the cylinder block, the inner hole diameter of the cylinder block after heating is millimeters, and the expansion amount is 2 millimeters.

[0025] The T-shaped ruler further includes two locking nuts, and the two locking nuts are respectively sleeved on the screws of the two measuring mushroom heads.

[0026] In the sixth step of heating the cylinder block, after the heat preservation ends, the operator holds the handle of the T-shaped ruler, makes the connecting rod enter the inner cavity of the cylinder block in the vertical direction, and at the same time the measuring rod of the T-shaped ruler is close to the diameter of the cylinder block. At this time, the handle is shaken radially along the cylinder block. When the measuring rod coincides with the diameter of the cylinder block, the measuring mushroom heads at both ends of the measuring rod are in transitional fit with the inner wall of the cylinder block. At this time, the expansion amount at this part of the cylinder block meets the requirements. When the measuring mushroom heads at both ends of the measuring rod still cannot pass through the inner wall of the cylinder block after adjustment, the expansion amount at this part of the cylinder block is too low.

[0027] In the seventh step of sleeving the workpiece, when there is an inner diameter in the cylinder block that does not meet the expansion amount requirement, or the cylinder block is less than 210 °C, the cylinder block is repeatedly subjected to the sixth step of heating the cylinder block.

[0028] A root clearing is arranged at the connection between the outer wall of the inner cylinder and the flange.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. In the high-precision assembly method of a large-sized cylinder block and an inner cylinder of the present invention, in the sixth step of heating the cylinder block, the cylinder block is heated to 390 to 400 °C and kept warm for four hours to expand the cylinder block. After the heat preservation ends, the operator measures the inner hole diameter of the cylinder block with a T-square to determine the passability between the cylinder block and the inner cylinder. Therefore, in this design, the expansion amount of the cylinder block can be measured with a T-square to check whether it meets the requirements, avoiding difficulties during assembly caused by interference fit between the cylinder block and the inner cylinder, and effectively improving the assembly efficiency.

[0031] 2. In the high-precision assembly method of a large-sized cylinder block and an inner cylinder of the present invention, in the second step of machining the lifting ring screw holes, the operator uses a drill press to machine three groups of lifting ring screw holes on the flange end face at the top of the cylinder block. The three groups of lifting ring screw holes are evenly distributed on the flange end face at the top of the cylinder block. At the same time, the lifting tool is a hoist with an adjustable wire rope length. The operator can adjust the length of the wire rope through the hoist, so that when lifting the cylinder block, the lifting tool can adjust the levelness of the cylinder block by the three-point positioning method. Before heating, marks are made on the lifting tool and the lifting rings with high-temperature marking paint, so that when the cylinder block is lifted again after heating, the correct correspondence between the lifting tool and the lifting rings can be ensured, and further ensure that the levelness of the cylinder block still meets the requirements. At the same time, in the fifth step of supporting the inner cylinder, the levelness of the inner cylinder end face is ensured by adjusting the height of each support block. By ensuring the levelness of the cylinder block and the inner cylinder respectively, the central axes of the cylinder block and the inner cylinder are kept parallel. Therefore, in this design, by ensuring the levelness of the cylinder block and the inner cylinder respectively, the central axes of the cylinder block and the inner cylinder can be kept parallel.

[0032] 3. In the high-precision assembly method of a large-sized cylinder block and an inner cylinder of the present invention, the T-square includes a measuring rod, a connecting rod, a handle, a double-headed bolt and two measuring mushroom heads. One measuring mushroom head is arranged at each end of the measuring rod. The distance between the ends of the two measuring mushroom heads is the same as the diameter of the inner hole of the cylinder block after heating. The middle part of the measuring rod is vertically connected to one end of the connecting rod, and the other end of the connecting rod is fixedly connected to the handle. When in use, the operator can measure the passability of the inner hole of the cylinder block with the measuring mushroom heads to ensure that the expansion amount of the inner hole of the cylinder block meets the requirements. Therefore, in this design, the passability of the inner hole of the cylinder block can be measured with the measuring mushroom heads to ensure that the expansion amount of the inner hole of the cylinder block meets the requirements.

[0033] 4. In the high-precision assembly method of a large-sized cylinder block and an inner cylinder of the present invention, each end of the measuring rod is threadedly connected to a measuring mushroom head, and the other end of the connecting rod is fixedly connected to the handle through a double-headed bolt. The operator can adjust the T-square by rotating the measuring mushroom heads, and at the same time, by rotating the double-headed bolt, the T-square can be adapted to different specifications of cylinder blocks and inner cylinders. Therefore, in this design, the size of the T-square can be adjusted to adapt to different specifications of cylinder blocks and inner cylinders, effectively expanding the adaptation range of the T-square. Description of the Drawings

[0034] Figure 1 It is a schematic structural diagram of the cylinder block in the present invention.

[0035] Figure 2 It is a schematic structural diagram of the inner cylinder in the present invention.

[0036] Figure 3 It is Figure 1 the top view of the middle cylinder block.

[0037] Figure 4 It is Figure 2 the schematic structural diagram of the flange.

[0038] Figure 5 It is the operation schematic diagram of the fifth step of supporting the inner cylinder in the present invention.

[0039] Figure 6 It is Figure 1 the schematic structural diagram of the support block.

[0040] Figure 7 It is the schematic structural diagram of the T-square in the present invention.

[0041] Figure 8 It is the measurement schematic diagram of the sixth step of heating the cylinder block in the present invention.

[0042] In the figure: cylinder block 1, flange end face 11, lifting ring screw hole 12, inner cylinder 2, inner cylinder thimble plate 21, inner cylinder clamping plate 22, flange 23, root cleaning 24, lifting ring 3, support flat plate 4, support block 5, L-shaped bottom plate 51, wedge block 52, adjusting bolt 53, horizontal plate 54, vertical plate 55, T-square 6, measuring rod 61, connecting rod 62, handle 63, double-headed bolt 64, measuring mushroom head 65, lock nut 66. Specific embodiments

[0043] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0044] Refer to Figures 1 to 8 , a high-precision assembly method for a large-size cylinder block and an inner cylinder, the assembly method is used for assembling the cylinder block 1 and the inner cylinder 2, the cylinder block 1 is sleeved on the inner cylinder 2, the diameters of the cylinder block 1 and the inner cylinder 2 are greater than one meter, the lengths of the cylinder block 1 and the inner cylinder 2 are greater than three meters, the cylinder block 1 is of a cylindrical structure, both ends of the cylinder block 1 are flange end faces 11, the inner wall of the cylinder block 1 is in interference fit with the outer wall of the inner cylinder 2, the inner cylinder 2 is of a cylindrical structure, an inner cylinder thimble plate 21 is detachably and fixedly arranged at the top end of the inner cylinder 2, an inner cylinder clamping plate 22 is detachably and fixedly arranged at the bottom end of the inner cylinder 2, and a flange 23 is arranged at the bottom end of the outer wall of the inner cylinder 2;

[0045] The assembly method includes:

[0046] First step: Check the dimensions of the workpiece. Place the completed cylinder block 1 and inner cylinder 2 on the inspection table, and use measuring tools to check whether the external dimensions of the cylinder block 1 and inner cylinder 2 meet the requirements of the drawing. If they do not meet the requirements of the drawing, the parts with non-conforming external dimensions will enter the repair process. If they meet the requirements of the drawing, proceed to the second step of machining the lifting ring screw holes 12.

[0047] Second step: Machine the lifting ring screw holes 12. Place the qualified cylinder block 1 on the machining table, and use a drill press to machine three groups of lifting ring screw holes 12 on the flange end face 11 at the top of the cylinder block 1. After the machining of the lifting ring screw holes 12 is completed, proceed to the third step of cleaning the workpiece.

[0048] Third step: Clean the cylinder block 1. Check whether there are machining defects such as burrs and chamfers inside and outside the cylinder block 1. If there are machining defects, remove them with a hand file. If there are no machining defects, clean the cylinder block 1 with acetone and dry it. After the cylinder block 1 is dry, proceed to the fourth step of lifting the workpiece.

[0049] Fourth step: Lift the cylinder block 1. Install a lifting ring 3 in each of the three groups of lifting ring screw holes 12 on the cylinder block 1. Install one end of each of the three sets of lifting tools and wire ropes into the three lifting rings 3 on the cylinder block 1. At the same time, make marks on the lifting rings 3 and the corresponding wire ropes with high-temperature marking paint. Fix the other ends of the three sets of lifting tools and wire ropes to the crane. After the installation of the three sets of lifting tools is completed, the operator starts the crane to lift the cylinder block 1. When the cylinder block 1 leaves the ground, the operator adjusts the length of the wire ropes through the three sets of lifting tools to make the end face of the cylinder block 1 horizontal. At this time, proceed to the fifth step of supporting the inner cylinder 2.

[0050] Fifth step: Support the inner cylinder 2. Place the inner cylinder 2 vertically on the support flat plate 4. When the inner cylinder 2 is placed on the support flat plate 4, the end of the inner cylinder 2 close to the inner cylinder clamping plate 22 is set facing the support flat plate 4. The support flat plate 4 is arranged on the ground through a plurality of height-adjustable support blocks 5. After the inner cylinder 2 is placed, the operator measures the levelness of the end face of the inner cylinder 2 with a level and adjusts the height of each support block 5 so that the levelness of the end face of the inner cylinder 2 is less than or equal to 0.5 mm. After the levelness of the end face of the inner cylinder 2 meets the requirements, proceed to the sixth step of heating the cylinder block 1.

[0051] Step 6: Heat the cylinder block 1. Set multiple cushion blocks at the bottom of the heating furnace cavity. Each cushion block is arranged facing the bottom of the cylinder block 1. After the cushion blocks are set, the operator controls the crane to start working, so that the cylinder block 1 enters the cavity of the heating furnace and vertically drops onto each cushion block. After the weight of the cylinder block 1 is fully supported by the cushion blocks, disassemble each set of lifting tools and wire ropes. After each set of lifting tools and wire ropes are disassembled, the operator closes the cavity of the heating furnace and starts the heating furnace until the temperature in the heating furnace cavity reaches 390 to 400 °C and keeps warm for four hours. After the heat preservation ends, the operator measures the inner hole diameter of the cylinder block 1 with a T-shaped ruler 6. When the difference between the inner hole diameter of the cylinder block 1 after heating and the inner hole diameter before heating meets the expansion amount requirement, enter Step 7, the workpiece sleeving step;

[0052] Step 7: Sleeve the workpiece. According to the marks in the cylinder block 1 hoisting step in Step 4, install one end of each of the three sets of lifting tools and wire ropes into the corresponding lifting rings 3 on the cylinder block 1 that has completed heating and meets the expansion amount requirement. Fix the other ends of the three sets of lifting tools and wire ropes to the crane, and start the crane to lift the cylinder block 1 directly above the inner cylinder 2 placed on the support flat plate 4. When the cylinder block 1 reaches directly above the inner cylinder 2, set an engineering double ladder on each side of the cylinder block 1. Two observers make their observation positions higher than the top of the cylinder block 1 through the engineering double ladder. At this time, the two observers detect the inner diameter of the cylinder block 1 with a T-shaped ruler 6, and at the same time measure the temperature of the cylinder block 1 with a high-temperature infrared spot thermometer. When the inner diameters at each part of the cylinder block 1 all meet the expansion amount requirement and the temperature of the cylinder block 1 is greater than or equal to 210 °C, the operator starts the crane to lower the cylinder block 1 and sleeve it on the inner cylinder 2. During the lowering process of the cylinder block 1, manually fine-tune the lifting tool to keep the gap between the inner wall of the cylinder block 1 and the outer wall of the inner cylinder 2 uniform. When the cylinder block 1 descends until the bottom of the cylinder block 1 touches the top of the flange 23 at the bottom end of the inner cylinder 2, the assembly of the cylinder block 1 and the inner cylinder 2 is completed.

[0053] In the step of machining the lifting ring screw holes 12 in the second step, the three sets of lifting ring screw holes 12 are evenly distributed on the flange end face 11 at one end corresponding to the top ends of the cylinder block 1 and the inner cylinder 2. Each set of lifting ring screw holes 12 includes two M24 threaded holes. For the lifting ring screw holes 12, the lifting rings 3 in the cylinder block 1 hoisting step in the fourth step are M24 lifting rings.

[0054] In the cylinder block 1 hoisting step in the fourth step, the lifting tool is a hoist with an adjustable wire rope length.

[0055] The support flat plate 4 is of a flat plate structure. A plurality of support blocks 5 are uniformly distributed between the outer edge of the bottom of the support flat plate 4 and the ground. The support block 5 includes an L-shaped bottom plate 51, a wedge block 52 and an adjusting bolt 53. The L-shaped bottom plate 51 includes a horizontal plate 54 and a vertical plate 55 which are perpendicularly connected to each other. The wedge block 52 is arranged on the top of the horizontal plate 54, and the vertical end of the wedge block 52 is arranged close to the vertical plate 55. A threaded hole matching with the adjusting bolt 53 is formed in the vertical plate 55, and the threaded rod of the adjusting bolt 53 is arranged close to the wedge block 52.

[0056] The T-shaped ruler 6 includes a measuring rod 61, a connecting rod 62, a handle 63, a double-headed bolt 64 and two measuring mushroom heads 65. An internal threaded hole is formed at each end of the measuring rod 61. The bottoms of the two measuring mushroom heads 65 are provided with screws matching with the internal threaded holes. The two measuring mushroom heads 65 are respectively fixedly connected to the internal threaded holes formed at the two ends of the measuring rod 61 through the screws arranged thereon. The distance between the ends of the two measuring mushroom heads 65 is equal to the designed inner diameter of the cylinder block 1. The middle part of the measuring rod 61 is fixedly connected to one end of the connecting rod 62. The measuring rod 61 and the connecting rod 62 are perpendicular to each other. The other end of the connecting rod 62 is fixedly connected to the handle 63 through the double-headed bolt 64.

[0057] In the step of the first inspection of the workpiece size, the designed inner diameter of the cylinder block 1 is millimeters, the designed outer diameter of the inner cylinder 2 is millimeters. In the step of the sixth heating of the cylinder block 1, the inner hole diameter of the cylinder block 1 after heating is millimeters, and the amount of expansion is 2 millimeters.

[0058] The T-shaped ruler 6 further includes two locking nuts 66. The two locking nuts 66 are respectively sleeved on the screws of the two measuring mushroom heads 65.

[0059] In the step of the sixth heating of the cylinder block, after the heat preservation is completed, the operator holds the handle 63 of the T-shaped ruler 6, makes the connecting rod 62 enter the inner cavity of the cylinder block 1 in the vertical direction, and at the same time, the measuring rod 61 of the T-shaped ruler 6 is close to the diameter of the cylinder block 1. At this time, the handle 63 is shaken radially along the cylinder block 1. When the measuring rod 61 coincides with the diameter of the cylinder block 1, the measuring mushroom heads 65 at both ends of the measuring rod 61 are in transitional fit with the inner wall of the cylinder block 1. At this time, the amount of expansion at this part of the cylinder block 1 meets the requirements. When the measuring mushroom heads 65 at both ends of the measuring rod 61 still cannot pass through the inner wall of the cylinder block 1 after adjustment, the amount of expansion at this part of the cylinder block 1 is too low.

[0060] In the step of the seventh workpiece sleeving, when there is an inner diameter in the cylinder block 1 that does not meet the expansion amount requirement, or the cylinder block 1 is lower than 210 °C, the cylinder block 1 is repeatedly subjected to the step of the sixth heating of the cylinder block 1.

[0061] A root cleaning 24 is provided at the connection between the outer wall of the inner cylinder 2 and the flange 23.

[0062] The principle of the present invention is described as follows:

[0063] In the first step of checking the workpiece dimensions in this design, the measuring tool is a vernier caliper with a measuring range of 1500 millimeters and a least count of 0.02 millimeters;

[0064] In the sixth step of heating the cylinder block 1, the distance between the ends of the two measuring mushroom heads 65 is measured by a vernier caliper;

[0065] The fifth step of supporting the inner cylinder 2 and the sixth step of heating the cylinder block 1 can be carried out simultaneously. The fifth step of supporting the inner cylinder 2 needs to be completed before the sixth step of heating the cylinder block 1, and the interval time between the completion of the fifth step of supporting the inner cylinder 2 and the sixth step of heating the cylinder block 1 is greater than or equal to thirty minutes.

[0066] Example 1:

[0067] A high-precision assembly method for a large-size cylinder block and an inner cylinder, the assembly method is used for assembling the cylinder block 1 and the inner cylinder 2, the cylinder block 1 is sleeved on the inner cylinder 2, the diameters of the cylinder block 1 and the inner cylinder 2 are greater than one meter, the lengths of the cylinder block 1 and the inner cylinder 2 are greater than three meters, the cylinder block 1 is a cylindrical structure, both ends of the cylinder block 1 are flange end faces 11, the inner wall of the cylinder block 1 and the outer wall of the inner cylinder 2 are in interference fit, the inner cylinder 2 is a cylindrical structure, the top end of the inner cylinder 2 is detachably and fixedly provided with an inner cylinder thimble plate 21, the bottom end of the inner cylinder 2 is detachably and fixedly provided with an inner cylinder clamping plate 22, and a flange 23 is provided at the bottom end of the outer wall of the inner cylinder 2;

[0068] The assembly method includes:

[0069] The first step: Check the workpiece dimensions. Place the completed cylinder block 1 and inner cylinder 2 on the inspection table, and check whether the external dimensions of the cylinder block 1 and inner cylinder 2 meet the requirements of the drawing by a measuring tool. If the external dimensions do not meet the requirements of the drawing, the parts with non-conforming external dimensions are sent to the repair process. If they meet the requirements of the drawing, proceed to the second step of machining the lifting ring screw holes 12;

[0070] The second step: Machine the lifting ring screw holes 12. Place the qualified cylinder block 1 on the machining table, and machine three groups of lifting ring screw holes 12 on the flange end face 11 at the top of the cylinder block 1 by a drill press. When the machining of the lifting ring screw holes 12 is completed, proceed to the third step of cleaning the workpiece;

[0071] The third step: Clean the cylinder block 1. Check whether there are machining defects such as burrs and chamfers inside and outside the cylinder block 1. If there are machining defects, remove them with a hand file. If there are no machining defects, clean the cylinder block 1 with acetone and dry it. When the cylinder block 1 is dry, proceed to the fourth step of hoisting the workpiece;

[0072] Step 4: Hoist the cylinder block 1. Install a lifting ring 3 in each of the three groups of lifting ring screw holes 12 on the cylinder block 1. Install one end of the three groups of lifting tools and steel wire ropes into the three lifting rings 3 on the cylinder block 1 respectively. At the same time, make marks on the lifting rings 3 and the corresponding steel wire ropes with high-temperature label paint. Fix the other ends of the three groups of lifting tools and steel wire ropes to the crane. After the installation of the three groups of lifting tools is completed, the operator starts the crane to lift the cylinder block 1. When the cylinder block 1 leaves the ground, the operator adjusts the length of the steel wire ropes through the three groups of lifting tools to make the end face of the cylinder block 1 horizontal. At this time, enter Step 5: Support the inner cylinder 2;

[0073] Step 5: Support the inner cylinder 2. Place the inner cylinder 2 vertically on the support flat plate 4. When the inner cylinder 2 is placed on the support flat plate 4, the end of the inner cylinder 2 close to the inner cylinder clamping plate 22 faces the support flat plate 4. The support flat plate 4 is arranged on the ground through a plurality of height-adjustable support blocks 5. After the inner cylinder 2 is placed, the operator measures the flatness of the end face of the inner cylinder 2 with a spirit level and adjusts the height of each support block 5 to make the flatness of the end face of the inner cylinder 2 less than or equal to 0.5 mm. When the flatness of the end face of the inner cylinder 2 meets the requirements, enter Step 6: Heat the cylinder block 1;

[0074] Step 6: Heat the cylinder block 1. Set a plurality of cushion blocks at the bottom of the heating furnace cavity. Each cushion block faces the bottom of the cylinder block 1. After the cushion blocks are set, the operator controls the crane to start working, so that the cylinder block 1 enters the cavity of the heating furnace and vertically drops onto each cushion block. After the weight of the cylinder block 1 is fully supported by the cushion blocks, disassemble each group of lifting tools and steel wire ropes. After the disassembly of each group of lifting tools and steel wires is completed, the operator closes the cavity of the heating furnace and starts the heating furnace until the temperature in the heating furnace cavity reaches 390 to 400 °C and keeps it warm for four hours. After the heat preservation is over, the operator measures the inner hole diameter of the cylinder block 1 with a T-shaped ruler 6. When the difference between the inner hole diameter of the cylinder block 1 after heating and the inner hole diameter before heating meets the expansion amount requirement, enter Step 7: Sleeve the workpiece;

[0075] Step 7: Assembling the workpiece. According to the marks in the cylinder block 1 hoisting step of Step 4, one end of the three sets of lifting tools and wire ropes are respectively installed into the corresponding lifting rings 3 on the cylinder block 1 whose expansion amount after heating meets the requirements. The other ends of the three sets of lifting tools and wire ropes are fixed to the crane, and then start the crane to hoist the cylinder block 1 above the inner cylinder 2 placed on the support flat plate 4. When the cylinder block 1 reaches directly above the inner cylinder 2, set up an engineering double ladder on each side of the cylinder block 1. Two observers use the engineering double ladder to make their observation positions higher than the top of the cylinder block 1. At this time, the two observers use the T-shaped ruler 6 to detect the inner diameter of the cylinder block 1, and at the same time measure the temperature of the cylinder block 1 with a high-temperature infrared pyrometer. When the inner diameters at all parts of the cylinder block 1 meet the expansion amount requirements and the temperature of the cylinder block 1 is greater than or equal to 210 °C, the operator starts the crane to lower the cylinder block 1 and sleeved it on the inner cylinder 2. During the lowering process of the cylinder block 1, manually fine-tune the lifting tool to keep the gap between the inner wall of the cylinder block 1 and the outer wall of the inner cylinder 2 uniform. When the cylinder block 1 descends until the bottom of the cylinder block 1 touches the top of the flange 23 at the bottom end of the inner cylinder 2, the assembly of the cylinder block 1 and the inner cylinder 2 is completed.

[0076] In the step of machining the lifting ring screw holes 12 in the second step, the three sets of lifting ring screw holes 12 are evenly distributed on the flange end face 11 at one end corresponding to the top of the cylinder block 1 and the inner cylinder 2. Each set of lifting ring screw holes 12 includes two M24 threaded holes. For the lifting ring screw holes 12, the lifting ring 3 in the cylinder block 1 hoisting step of Step 4 is an M24 lifting ring; in the cylinder block 1 hoisting step of Step 4, the lifting tool is a hoist with an adjustable wire rope length; the support flat plate 4 is a flat plate structure, and a plurality of support blocks 5 are evenly distributed between the outer edge at the bottom of the support flat plate 4 and the ground. The support block 5 includes an L-shaped bottom plate 51, a wedge block 52 and an adjusting bolt 53. The L-shaped bottom plate 51 includes a horizontal plate 54 and a vertical plate 55 which are perpendicularly connected. The wedge block 52 is arranged on the top of the horizontal plate 54, and the vertical end of the wedge block 52 is close to the vertical plate 55. A threaded hole matching the adjusting bolt 53 is opened on the vertical plate 55, and the threaded rod of the adjusting bolt 53 is close to the wedge block 52; in the step of checking the workpiece size in the first step, the designed inner diameter of the cylinder block 1 is millimeters, the designed outer diameter of the inner cylinder 2 is millimeters, the inner hole diameter of the cylinder block 1 after heating in the cylinder block 1 heating step of Step 6 is millimeters, and the expansion amount is 2 millimeters; the T-shaped ruler 6 further includes two locking nuts 66, and the two locking nuts 66 are respectively sleeved on the screws of the two measuring mushroom heads 65; in the step of assembling the workpiece in Step 7, when there is an inner diameter in the cylinder block 1 that does not meet the expansion amount requirements, or the temperature of the cylinder block 1 is less than 210 °C, repeat the cylinder block 1 heating step of Step 6 for this cylinder block 1; there is a root clearing 24 at the connection between the outer wall of the inner cylinder 2 and the flange 23.

[0077] Embodiment 2:

[0078] Example 2 is basically the same as Example 1, except that:

[0079] The T-shaped ruler 6 includes a measuring rod 61, a connecting rod 62, a handle 63, a double-headed bolt 64 and two measuring mushroom heads 65. An internal threaded hole is provided at each end of the measuring rod 61. Screws matching the internal threaded holes are provided at the bottoms of the two measuring mushroom heads 65. The two measuring mushroom heads 65 are respectively fixedly connected to the internal threaded holes provided at both ends of the measuring rod 61 through the screws provided thereon. The distance between the ends of the two measuring mushroom heads 65 is equal to the designed inner diameter of the cylinder block 1. The middle of the measuring rod 61 is fixedly connected to one end of the connecting rod 62. The measuring rod 61 and the connecting rod 62 are perpendicular to each other. The other end of the connecting rod 62 is fixedly connected to the handle 63 through the double-headed bolt 64.

[0080] Example 3:

[0081] Example 3 is basically the same as Example 2, except that:

[0082] In the sixth step of heating the cylinder block, after the heat preservation ends, the operator holds the handle 63 of the T-shaped ruler 6, so that the connecting rod 62 enters the inner cavity of the cylinder block 1 in the vertical direction. At the same time, the measuring rod 61 of the T-shaped ruler 6 is close to the diameter of the cylinder block 1. At this time, the handle 63 is shaken radially along the cylinder block 1. When the measuring rod 61 coincides with the diameter of the cylinder block 1, the measuring mushroom heads 65 at both ends of the measuring rod 61 are in transitional fit with the inner wall of the cylinder block 1. At this time, the expansion amount at this place of the cylinder block 1 meets the requirements. When the measuring mushroom heads 65 at both ends of the measuring rod 61 still cannot pass through the inner wall of the cylinder block 1 after adjustment, the expansion amount at this place of the cylinder block 1 is too low.

[0083] The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. Any equivalent modification or change made by those of ordinary skill in the art according to the disclosure of the present invention should be included in the protection scope recorded in the claims.

Claims

1. A high-precision assembly method for a large-sized cylinder block and an inner cylinder, characterized in that: The assembly method is used to assemble the cylinder block (1) and the inner cylinder (2). The cylinder block (1) is sleeved on the inner cylinder (2). The diameters of the cylinder block (1) and the inner cylinder (2) are greater than one meter, and the lengths of the cylinder block (1) and the inner cylinder (2) are greater than three meters. The cylinder block (1) is of a cylindrical structure, and both ends of the cylinder block (1) are flange end faces (11). The inner wall of the cylinder block (1) is in interference fit with the outer wall of the inner cylinder (2). The inner cylinder (2) is of a cylindrical structure, and an inner cylinder thimble plate (21) is detachably and fixedly arranged at the top end of the inner cylinder (2), and an inner cylinder clamping plate (22) is detachably and fixedly arranged at the bottom end of the inner cylinder (2). A flange (23) is arranged at the bottom end of the outer wall of the inner cylinder (2); The assembly method includes: The first step: Check the workpiece dimensions. Place the completed cylinder block (1) and inner cylinder (2) on the inspection table, and use measuring tools to check whether the external dimensions of the cylinder block (1) and inner cylinder (2) meet the requirements of the drawing. If they do not meet the requirements of the drawing, the parts with external dimensions not meeting the drawing requirements will enter the repair process. If they meet the requirements of the drawing, then enter the second step of processing the lifting ring screw holes (12); The second step: Process the lifting ring screw holes (12). Place the inspected cylinder block (1) on the processing table, and use a drill press to process three groups of lifting ring screw holes (12) on the flange end face (11) at the top of the cylinder block (1). When the processing of the lifting ring screw holes (12) is completed, enter the third step of cleaning the workpiece; The third step: Clean the cylinder block (1). Check whether there are machining defects such as burrs and chamfers inside and outside the cylinder block (1). If there are machining defects, remove them with a hand file. If there are no machining defects, clean the cylinder block (1) with acetone and dry it. When the cylinder block (1) is dry, enter the fourth step of lifting the workpiece; The fourth step: Lift the cylinder block (1). Install a lifting ring (3) in each of the three groups of lifting ring screw holes (12) on the cylinder block (1). Install one end of each of the three groups of lifting tools and steel wire ropes into the three lifting rings (3) on the cylinder block (1). At the same time, make marks on the lifting rings (3) and the corresponding steel wire ropes with high-temperature grade paint. Fix the other ends of the three groups of lifting tools and steel wire ropes to the crane. When the installation of the three groups of lifting tools is completed, the operator starts the crane to lift the cylinder block (1). When the cylinder block (1) leaves the ground, the operator adjusts the length of the steel wire ropes through the three groups of lifting tools to make the end face of the cylinder block (1) horizontal. At this time, enter the fifth step of supporting the inner cylinder (2); Step 5: Support the inner cylinder (2). Place the inner cylinder (2) vertically on the support flat plate (4). When the inner cylinder (2) is placed on the support flat plate (4), the end of the inner cylinder (2) near the inner cylinder clamping plate (22) is arranged facing the support flat plate (4). The support flat plate (4) is arranged on the ground through a plurality of height-adjustable support blocks (5). After the inner cylinder (2) is placed, the operator measures the levelness of the end face of the inner cylinder (2) with a level and adjusts the height of each support block (5) so that the levelness of the end face of the inner cylinder (2) is less than or equal to 0.5 mm. After the levelness of the end face of the inner cylinder (2) meets the requirements, proceed to Step 6 of heating the cylinder block (1). Step 6: Heat the cylinder block (1). Arrange a plurality of cushion blocks at the bottom of the heating furnace cavity. Each cushion block is arranged facing the bottom of the cylinder block (1). After the cushion blocks are arranged, the operator controls the crane to start working, so that the cylinder block (1) enters the cavity of the heating furnace and vertically drops onto each cushion block. After the weight of the cylinder block (1) is fully supported by the cushion blocks, disassemble each set of lifting tools and wire ropes. After each set of lifting tools and wire ropes are disassembled, the operator closes the cavity of the heating furnace and starts the heating furnace until the temperature in the heating furnace cavity reaches 390 to 400 °C and keeps it warm for four hours. After the heat preservation ends, the operator measures the inner hole diameter of the cylinder block (1) with a T-shaped ruler (6). When the difference between the inner hole diameter of the cylinder block (1) after heating and the inner hole diameter before heating meets the expansion amount requirement, proceed to Step 7 of sleeving the workpiece. Step 7: Sleeve the workpiece. According to the marks in Step 4 of hoisting the cylinder block (1), install one end of each of the three sets of lifting tools and wire ropes into the corresponding lifting rings (3) on the cylinder block (1) that has been heated and whose expansion amount meets the requirements. Fix the other ends of the three sets of lifting tools and wire ropes to the crane, and start the crane to hoist the cylinder block (1) directly above the inner cylinder (2) placed on the support flat plate (4). When the cylinder block (1) reaches directly above the inner cylinder (2), place an engineering double ladder on each side of the cylinder block (1). Two observers make their observation positions higher than the top of the cylinder block (1) through the engineering double ladder. At this time, the two observers use a T-shaped ruler (6) to detect the inner diameter of the cylinder block (1), and at the same time measure the temperature of the cylinder block (1) with a high-temperature infrared spot thermometer. When the inner diameters at all parts of the cylinder block (1) meet the expansion amount requirements and the temperature of the cylinder block (1) is greater than or equal to 210 °C, the operator starts the crane to lower the cylinder block (1) and sleeve it on the inner cylinder (2). During the descent of the cylinder block (1), manually fine-tune the lifting tool to keep the gap between the inner wall of the cylinder block (1) and the outer wall of the inner cylinder (2) uniform. When the cylinder block (1) descends until the bottom of the cylinder block (1) touches the top of the flange (23) at the bottom end of the inner cylinder (2), the assembly of the cylinder block (1) and the inner cylinder (2) is completed.

2. The high-precision assembly method for a large-size cylinder block and an inner cylinder according to claim 1, characterized in that: In the step of machining the lifting ring screw holes (12) in the second step, the three groups of lifting ring screw holes (12) are evenly distributed on the flange end face (11) at one end corresponding to the top of the cylinder block (1) and the inner cylinder (2). Each group of lifting ring screw holes (12) includes two M24 threaded holes. For the lifting ring screw holes (12), in the step of hoisting the cylinder block (1) in the fourth step, the lifting ring (3) is an M24 lifting ring.

3. A high-precision assembly method for a large-sized cylinder block and an inner cylinder according to claim 2, characterized in that: In the step of hoisting the cylinder block (1) in the fourth step, the lifting tool is a hoist with an adjustable wire rope length.

4. A high-precision assembly method for a large-sized cylinder block and an inner cylinder according to claim 3, characterized in that: The support flat plate (4) has a flat plate structure. A plurality of support blocks (5) are evenly distributed between the outer edge of the bottom of the support flat plate (4) and the ground. The support block (5) includes an L-shaped bottom plate (51), a wedge block (52) and an adjustment bolt (53). The L-shaped bottom plate (51) includes a horizontal plate (54) and a vertical plate (55) that are perpendicularly connected to each other. The wedge block (52) is arranged on the top of the horizontal plate (54). The vertical end of the wedge block (52) is arranged close to the vertical plate (55). A threaded hole matching the adjustment bolt (53) is opened on the vertical plate (55). The threaded rod of the adjustment bolt (53) is arranged close to the wedge block (52).

5. A high-precision assembly method for a large-sized cylinder block and an inner cylinder according to any one of claims 1 to 4, characterized in that: The T-shaped ruler (6) includes a measuring rod (61), a connecting rod (62), a handle (63), a double-headed bolt (64) and two measuring mushroom heads (65). An internal threaded hole is opened at each end of the measuring rod (61). The bottoms of the two measuring mushroom heads (65) are provided with screws matching the internal threaded holes. The two measuring mushroom heads (65) are respectively fixedly connected to the internal threaded holes opened at both ends of the measuring rod (61) through the screws provided thereon. The distance between the ends of the two measuring mushroom heads (65) is equal to the designed inner diameter of the cylinder block (1). The middle part of the measuring rod (61) is fixedly connected to one end of the connecting rod (62). The measuring rod (61) and the connecting rod (62) are perpendicular to each other. The other end of the connecting rod (62) is fixedly connected to the handle (63) through the double-headed bolt (64).

6. A high-precision assembly method for a large-sized cylinder block and an inner cylinder according to claim 5, characterized in that: In the first step of checking the workpiece size, the designed inner diameter of the cylinder block (1) is millimeters, the designed outer diameter of the inner cylinder (2) is millimeters. In the sixth step of heating the cylinder block (1), the inner hole diameter of the cylinder block (1) after heating is millimeters, and the expansion amount is 2 millimeters.

7. A high-precision assembly method for a large-sized cylinder block and an inner cylinder according to claim 6, characterized in that: The T-shaped ruler (6) further includes two locking nuts (66). The two locking nuts (66) are respectively sleeved on the screws of the two measuring mushroom heads (65).

8. A high-precision assembly method for a large-sized cylinder block and an inner cylinder according to claim 7, characterized in that: In the sixth step of heating the cylinder block, after the heat preservation is completed, the operator holds the handle (63) of the T-shaped ruler (6), makes the connecting rod (62) enter the inner cavity of the cylinder block (1) in the vertical direction, and at the same time, the measuring rod (61) of the T-shaped ruler (6) is close to the diameter of the cylinder block (1). At this time, shake the handle (63) radially along the cylinder block (1). When the measuring rod (61) coincides with the diameter of the cylinder block (1), the measuring mushroom heads (65) at both ends of the measuring rod (61) are in transitional fit with the inner wall of the cylinder block (1). At this time, the expansion amount at this part of the cylinder block (1) meets the requirements. When the measuring mushroom heads (65) at both ends of the measuring rod (61) still cannot pass through the inner wall of the cylinder block (1) after adjustment, the expansion amount at this part of the cylinder block (1) is too low.

9. A high-precision assembly method for a large-size cylinder block and an inner cylinder according to claim 8, characterized in that: In the seventh step of sleeving the workpiece, when there is an inner diameter in the cylinder block (1) that does not meet the expansion amount requirement, or when the cylinder block (1) is less than 210 °C, the cylinder block (1) is repeatedly subjected to the sixth step of heating the cylinder block (1).

10. A high-precision assembly method for a large-size cylinder block and an inner cylinder according to claim 9, characterized in that: A root cleaning (24) is provided at the connection between the outer wall of the inner cylinder (2) and the flange (23).

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