Technical specifications for mechanical assembly, necessary for robots

1. Preparation before homework

1. Work data: including general assembly drawings, component assembly drawings, parts drawings, material BOM lists, etc., until the end of the project, the integrity of the drawings, cleanliness, and process information records must be ensured.

2. Workplace: The placement and assembly of parts must be carried out in the specified work place. The place for the placement and assembly of the whole machine must be clearly planned until the end of the entire project. All work places must be kept tidy, standardized and orderly.

3. Assembly materials: Before the operation, the assembly materials specified in the assembly process must be in place on time. If some non-deterministic materials are not in place, you can change the order of work, and then fill in the material reminder and submit it to the purchasing department.

4. Before assembling, understand the structure, assembly technology and process requirements of the equipment.

  2. Basic specifications

1. The mechanical assembly should be assembled in strict accordance with the assembly drawings and process requirements provided by the design department. It is strictly forbidden to modify the content of the operation or change the parts in an abnormal way.

2. Assembled parts must be qualified parts checked and accepted by the quality inspection department. If any unqualified parts missed during the assembly process are found, they should be reported in time.

3. The assembly environment must be clean and free of dust or other pollution. The parts should be stored in a dry, dust-free place with protective pads.

4. During the assembling process, the parts must not be bumped, cut, damaged, or cause obvious bending, twisting, or deformation of the surface of the part, and the mating surface of the part must not be damaged.

5. For relatively moving parts, lubricating oil (grease) should be added between the contact surfaces during assembly.

6. The matching dimensions of matching parts must be accurate.

7. When assembling, there should be special facilities for placing parts and tools. In principle, parts and tools are not allowed to be placed on the machine or directly on the ground. If necessary, protective mats or carpets should be laid on the place.

8. In principle, it is not allowed to step on the machine during assembly. If stepping is required, protective mats or carpets must be laid on the machine. Important parts and non-metallic parts with low strength are strictly prohibited from stepping on.

  Three, connection method

1. Bolt connection

(1) When the bolts are tightened, an adjustable wrench shall not be used, and no more than one washer of the same type shall be used under each nut. After the countersunk screw is tightened, the nail head shall be embedded in the machine part and shall not be exposed.

(2) Under normal circumstances, threaded connections should have anti-loosening spring washers. The tightening method of symmetrical multiple bolts should be gradually tightened in a symmetrical sequence, and the strip connectors should be tightened symmetrically from the middle to two directions.

(3) After the bolts and nuts are tightened, the bolts should expose 1 to 2 pitches of the nuts; when the screws do not need to be disassembled during the tightening of the moving device or for maintenance, thread glue should be applied to the screws before assembly.

(4) For fasteners with specified tightening torque requirements, a torque wrench should be used and tightened according to the specified tightening torque.

2. Pin connection

(1) The end surface of the positioning pin should generally be slightly higher than the surface of the part. After the taper pin with screw tail is installed in the relevant part, its large end should sink into the hole.

(2) After the cotter pin is installed in the relevant parts, its tail should be separated by 60°~90°.

3. Coupling

(1) The two sides of the keyway of the flat key and the fixed key should be evenly contacted, and there should be no gap between the mating surfaces.

(2) After the key (or spline) with clearance fit is assembled, when the relative moving parts move along the axial direction, there must be no unevenness of tightness.

(3) The contact area of the hook key and wedge key after assembling should not be less than 70% of the working area, and the non-contacting part should not be concentrated in one place; the length of the exposed part should be 10% to 15% of the length of the inclined surface.

4. Riveting

(1) The material and size of riveting must meet the design requirements, and the processing of rivet holes must meet the requirements of relevant standards.

(2) During riveting, the surface of the riveted part must not be damaged or deformed.

(3) Except for special requirements, generally there should be no loosening after riveting. The head of the rivet must be in close contact with the riveted part, and it should be smooth and round.

5. Expansion sleeve connection

Expansion set matching: Apply lubricating grease to the expansion sleeve, put the expansion sleeve into the assembly hub hole, set the installation shaft and adjust the assembly position, and then tighten the bolts. The tightening sequence is bounded by the open seam, and the left and right are cross-symmetrically tightened one after the other to ensure that the rated torque value is reached.

6. Tighten the connection

The taper end and the hole of the taper end tightening screw should be 90°, and the tightening screw should be aligned with the hole and tightened.

  Fourth, the assembly of rolling bearings

1. Before the bearing is assembled, there must be no contamination in the bearing position.

2. When assembling the bearing, apply a layer of lubricating oil on the surface of the mating part, and the end of the bearing without a model number should face inward, that is, against the shaft shoulder.

3. Special press tools should be used when assembling the bearing, and it is strictly forbidden to assemble the bearing by direct hitting. The magnitude, direction and position of the force should be appropriate when the bearing is assembled. The protective frame or rolling elements should not be stressed, and the force should be uniform and symmetrical. , Ensure that the end face is perpendicular to the shaft.

4. The end face of the inner ring of the bearing should generally be close to the shaft shoulder (shaft clamp). After the outer ring of the bearing is assembled, the contact between the bearing cap of the positioning end and the washer or outer ring should be even.

5. After the rolling bearing is installed, the rotation of the relative moving parts should be flexible and light. If there is jamming, check and analyze the cause of the problem and deal with it accordingly.

6. In the process of bearing assembly, if the hole or shaft fit is found to be too loose, the tolerance should be checked; when the bearing is too tight, the rough assembly should not be forced, and the cause of the problem should be checked and analyzed and dealt with accordingly.

7. When assembling single-row tapered roller bearings, angular contact thrust bearings, and double-direction thrust ball bearings, the axial clearance meets the drawing and process requirements.

8. For bearings that use grease and their mating surfaces, proper amount of grease should be injected after assembly. For bearings whose operating temperature does not exceed 65℃, ZG-5 grease can be adopted according to GB491-65 "Calcium-based Grease"; for bearings whose operating temperature is higher than 65℃, it can be adopted according to GB492-77 "Calcium-based Grease" ZN-2ZN-3 grease.

9. The temperature rise of ordinary bearings during normal operation should not exceed 35℃, and the maximum temperature during operation should not exceed 70℃.

  5. Assembly of linear bearing

1. Before assembly, grease should be applied to the inside of the bearing.

2. When the bearing is pressed into the support seat, a special installation tool should be used to press against the end face of the outer ring, and it is not allowed to directly hit the bearing to avoid deformation.

3. The fit of the bearing and the supporting seat must meet the tolerance requirements. Too tight makes the guide shaft and the bearing interference fit, which will damage the bearing; too loose will make the bearing unable to be fixed in the supporting seat.

4. When the guide shaft is installed into the bearing, it should be inserted gently in the center. If it is inserted slantingly, the ball will fall off and the cage will be deformed.

5. When the bearing is installed into the supporting seat, it is not allowed to rotate. Forcibly rotating it will damage the bearing.

6. It is not allowed to use a set screw to directly tighten the outer ring of the bearing, otherwise it will be deformed.

  Six, the assembly of linear guide

1. The installation part of the guide rail must be free of dirt, and the flatness of the installation surface must meet the requirements.

2. When there is a reference edge on the side of the guide rail, it should be installed close to the reference side. If there is no reference side, ensure that the sliding direction of the guide rail is consistent with the design requirements. After the fixing screws of the guide rail are tightened, check whether the sliding direction of the slider is deviated, otherwise Must be adjusted.

3. If the sliding block is driven by a transmission belt, after the transmission belt and the sliding block are fixed and tensioned, the transmission belt must not be inclined, otherwise the pulley must be adjusted so that the driving direction of the transmission belt is parallel to the guide rail.

  Seven, sprocket chain assembly

1. The fit of the sprocket and the shaft must meet the design requirements.

2. The geometric center planes of the gear teeth of the driving sprocket and the driven sprocket should coincide, and the offset should not exceed the design requirements. If the design is not specified, it should generally be less than or equal to 2‰ of the center distance between the two wheels.

3. When the chain meshes with the sprocket, the working edge must be tightened to ensure smooth meshing.

4. The sag of the non-working side of the chain should meet the design requirements. If the design is not specified, it should be adjusted according to the center distance between the two sprockets 1% to 2%.

  8. Gear assembly

1. After the meshing gears are assembled, when the gear rim width is less than or equal to 20mm, the axial misalignment shall not be greater than 1mm; when the gear rim width is greater than 20mm, the axial misalignment shall not exceed 5% of the rim width.

2. The installation accuracy requirements of cylindrical gears, bevel gears and worm drives should be specified in JB179-83 "Involute Cylindrical Gear Accuracy", JB180-60 "Bevel Gear Transmission Tolerance" and JB162- according to the accuracy and specifications of the transmission parts. 60 "Worm Drive Tolerance" is determined.

3. The gear meshing surface needs to be lubricated according to the technical requirements, and the gear box needs to be filled with lubricating oil to the oil level line according to the technical requirements.

4. The noise of the gearbox running at full load shall not be greater than 80dB.

  Nine, the assembly of the synchronous pulley

1. The shafts of the driving and driven synchronous belt wheels must be parallel to each other, skew and swing are not allowed, and the inclination error should not exceed 2‰.

2. When the two pulleys have the same width, their end faces should be on the same plane, and the axial misalignment of the two pulleys should not exceed 5% of the width of the rim.

3. When assembling the timing belt, do not pry into the pulley forcibly, and should be assembled by shortening the center distance between the two pulleys, otherwise the tensile layer of the timing belt may be damaged.

4. The timing belt tensioner should be installed on the loose side to be tensioned, and two fastening bolts should be fixed.

  10. Assembly of flat belt

1. Before installation, all conveying planes should be leveled.

2. The line connecting the center points of the pulleys should be adjusted to the same vertical plane, and the axes are parallel to each other.

3. The conveying direction of the flat belt should be installed in the direction of the arrow marked on the belt, otherwise its service life will be affected.

  11. Assembly of motor and reducer

1. Check whether the motor model is correct and the reducer model is correct.

2. Before assembling, clean the motor shaft and the connecting part of the speed reducer.

3. Before tightening the motor flange screws, rotate the motor to correct the concentricity of the motor shaft and the reducer coupling, then connect the motor flange to the reducer, and tighten the fixing bolts diagonally.

4. During the assembly process of the servo motor, ensure that the encoder at the rear of the motor is not affected by external force, and it is strictly forbidden to knock the servo motor shaft.

5. Installation of servo reducer:

(1) Move the sealing screw on the outside of the flange of the reducer to facilitate adjustment of the clamping screw.

(2) Unscrew the clamping screw, connect the motor flange to the reducer, and tighten the positioning bolts diagonally.

(3) Tighten the clamping ring with appropriate torque, and then tighten the sealing screw.

(4) Twist the motor flange bolts until they are loose, jog the servo motor shaft or turn the motor shaft several times by hand to correct the concentricity of the motor shaft and the reducer coupling.

(5) Finally, connect the motor flange to the reducer, and tighten the positioning bolts diagonally.

  12. Adjustment and connection of the frame

1. The height adjustment of the racks of different sections should be adjusted to the same height according to the same reference point.

2. The wall panels of all racks should be adjusted to the same vertical surface.

3. After the racks of each section are adjusted in place and meet the requirements, the fixed connecting plates between each other should be installed.

  13. Assembly of pneumatic components

1. The configuration of each pneumatic drive device must be connected in strict accordance with the air circuit diagram provided by the design department, and the valve body, pipe joints, cylinders, etc. must be checked when connecting.

2. The inlet and outlet connections of the main intake pressure reducing valve are in the direction of the arrow, and the water cup and oil cup of the air filter and the oil mist device must be installed vertically downwards.

3. Before piping, the cutting powder and dust in the pipe should be fully blown out.

4. The pipe joint is screwed in. If the pipe thread does not have thread glue, the raw material tape should be wound. The winding direction is clockwise when viewed from the front. The raw material tape shall not be mixed into the valve and the raw material tape shall be wound. When setting, 1 thread should be reserved.

5. The air pipe should be arranged neatly and beautifully. Try not to cross it. The 90° elbow should be used at the turning point. Do not put extra stress on the joint when fixing the air pipe, otherwise it will cause air leakage.

6. When connecting the solenoid valve, pay attention to the role of each port number on the valve: P: total intake; A: exhaust 1; B: exhaust 2; R (EA): exhaust corresponding to A; S (EB): Exhaust corresponding to B.

7. When assembling the cylinder, the axis of the piston rod should be consistent with the direction of the load movement.

8. When using linear bearing to guide, after the front end of the cylinder piston rod is connected with the load, there must be no other force during the whole stroke, otherwise the cylinder will be damaged.

9. When using a throttle valve, pay attention to the type of throttle valve. Generally speaking, it is distinguished by the large arrow marked on the valve body. The cylinder with the large arrow pointing to the threaded end is used for the cylinder; the large arrow pointing to the pipe end is for the solenoid valve.

  14. Assembly inspection work

1. Every time a component is assembled, it must be checked according to the following items. If an assembly problem is found, it should be analyzed and dealt with in time.

(1) The completeness of the assembly work, check the assembly drawings, and check for missing parts.

(2) For the accuracy of the installation position of each part, check the assembly drawing or check the requirements as described in the above specification.

(3) The reliability of each connection part, whether each fastening screw meets the torque required for assembly, and whether the special fastener meets the requirements for preventing loosening.

(4) The flexibility of the movement of the movable parts, such as whether there is jamming or lagging phenomenon, whether there is eccentricity or bending when the conveying roller, belt wheel, guide rail, etc. are manually rotated or moved.

2. After the final assembly is completed, the connection between the assembly parts is mainly checked. The inspection content shall be based on the "four characteristics" specified in (1) as the measurement standard.

3. After the final assembly, the iron filings, sundries, dust, etc. should be cleaned up in all parts of the machine to ensure that there are no obstacles in the transmission parts.

4. When testing the machine, carefully monitor the start-up process. After the machine is started, immediately observe whether the main working parameters and moving parts are moving normally.

5. The main working parameters include the speed of the movement, the stability of the movement, the rotation of each drive shaft, temperature, vibration and noise.