In mechanical design, the principle of selection of standard parts, consider it!

1. Determine category

Standard fastening components are divided into ten categories. When selection, it should be determined according to the use of standard fasteners and their usage functions.

① Bolt: The bolt is generally matched with the nut (usually add one pad or two cushions) to play a occasion for connection and fastening.

② Nide: Steel and bolt are used.

③ Screw: Screws are usually used alone (sometimes adding cushions), which generally plays a tight or fixed effect.

④ Nail: Nails are generally carried on both ends (single -headed threads are single -ended with threads). Usually, one tattoo is firmly screwed into the component body, and the other end is matched with the nut. , But to a large extent, it has a fixed -range effect.

⑤ Circle: The pads are used between the branches of bolt, screw and nut and the process support of the process support to play a role in preventing loosening and reducing support for support.

⑥ Self -attack screws: The workpiece threads that match the self -attack screw do not need to attack the wire in advance. While screwing into the self -attack screw, the inner thread will be formed.

⑦ Rivet: There is a head at the end of the rivet, and there is no thread at the pole. When using, insert the pole into the hole of the connector, and then riven the end of the rod to the connection or fastener.

⑧ Sales: Inlaid in use in use in use in use, usually connect or positioning.

⑨ Sweet ring: The gear is usually on the axis or holes to restrict the axial effect of workpieces.

⑩ Wood screw: Wood screws are used to screw into wood, connecting or fastening.

2. Determine standards and varieties

1. Principles of varieties

(1) From the efficiency of processing and assembly work, in the same machinery or engineering, the variety of standard parts should be reduced as much as possible.

(2) From economic considerations, the variety of product standards should be selected first.

(3) According to the requirements of the expected use of the standard parts, the selection varieties are determined according to the type, mechanical performance, accuracy, and thread.

2. Type type

(1) bolt

① Generally use bolts: There are many varieties, including hexagonal heads and square heads. See national standard GB5780 -GB5790, etc.

② Bolt of hinge holes: When using, the bolt is tightly inlaid into the hole made of the hinge to prevent the workpiece from dislocation, see GB27 and so on.

③ Stop bolt: There are square necks and vertebral vertebrals, see GB12-15 and so on.

④ Special use bolts: such as T -shaped groove bolts, see GB37; live bolts, see GB798; ground foot bolts, see GB799 and so on.

⑤ High -strength bolts are connected to the steel structure: Generally used for friction -type connections of steel structures such as building, bridge, tower, pipeline brackets, and lifting machinery, see GB3632, etc.

(2) Narut

① General use nut: mainly refers to the hexagonal nut, and there are also square nuts. There are many varieties. See GB41, GB6170-6177, etc.

② Slot nut: mainly refers to the hexagonal slot nut, which is processed above the hexagonal nut. It is used in conjunction with the screw bolt bolt and opening to prevent the relative rotation of bolts and nuts, see GB6178-6181, etc.

③ Locking nut: Refers to nuts with locking function. There are nylon embedded hexagonal locking nuts.

④ Special use nuts: such as discs, see GB62; ring nuts, see GB63; covering nuts, see GB802, GB923; rolling nuts, see GB806, GB807 and embedded nuts, and GB809.

(3) Screw

① Machine screw: Different from the head shape and slot type, it is divided into many varieties. There are two types of head shapes, plate heads, deep heads, and semi -semi -headed heads. See GB65, GB67-69 and GB818-820.

② Tighten the screw: The screw is tightly used to use its tail end to prevent the interconnection between workpieces and the effect of less torque and less torque. See GB71, GB73-75, GB77, GB78, etc.

③ Inner hexagonal screws: Inner hexagonal screws are suitable for occasions where the installation space is small or the screw head needs to be buried. See GB70, GB6190, GB6191 and GB2672-2674.

④ Special use screws: such as positioning screws, see GB72, GB828, GB829; do not take off the screws, see GB827-839, GB948, GB948 and suspension screws, and GB825.

(4) Step

① Do not wait for long double -headed threads: suitable for one end to screw into the component body, set up a connection or fastening effect. See GB897-900, etc.

② Waiting for long double -headed nuts: suitable for connecting with nuts, connecting or fixed -spatial effects. See GB901, GB953, etc.

(5) Circle

① Flat padding circle: It is used to overcome the stress area of the inheritance of the workpiece and increase the support area. See GB848, GB95-97 and GB5287.

② Spring (elastic) cushion: See GB93, GB859, etc. in spring pads, and the elastic pads are seen in GB860, GB955, etc.

③ Anti -retreat pad: There are inner teeth locking pads, see GB861; outer tooth locking pads, see GB862; single ear stopped pads, see GB854; double ear stopped pad Wait.

④ Landscape cushion ring: In order to adapt to the obliqueness of the workpiece support surface, the oblique cushion ring can be used. The square oblique cushion ring with workers is seen in GB852;

(6) Self -attack screw

① Ordinary self -attack screws: The thread is in line with GB5280 (self -attack screws), which is large and suitable for use on thin steel plates or copper, aluminum, and plastic. See GB845-847, GB5282-5284, etc.

② Self -attack lock screw: The thread is in line with ordinary rice -made thick tooth threads, which is suitable for use in need of vibration resistance. See GB6560-6564.

(7) Riveting

① Hot forging rivets: The general specifications are large, and are mostly used for locomotive, ships and boilers, etc., and usually need to form the head to form the head through the heat forging. See GB863-866.

② Cold 型 rivets: Generally, the diameter specifications ≤16mm, usually the head is formed by coldness. See GB867-870, GB109, etc.

③ Halfly and half -air heart rivets: hollow rivets, see GB976; semi -air heart rivets, see GB873-875, etc.

④ Special purpose rivets: head rivets, see GB1016; pipe rivets, see GB975; signs rivets, see GB827, etc.

⑤ Core rivet: It is a single -sided rivet rivet. It is a new type of rivet that has been widely used in recent years. It has the characteristics of rapid, safety, convenience, and has the advantages of waterproof and anti -leakage.

(8) Sales

① Circular sales: there is no thread cylindrical sales, see GB119; internal thread cylindrical sales, see GB120; outer thread cylindrical sales, see GB878; elastic cylindrical sales, see GB879; with hole cylindrical sales, see GB880 and so on.

② cone sales: there is no thread cylindrical sales, see GB117; internal thread cylindrical sales, see GB118; threaded cone sales, see GB881; open tail cone sales, see GB877.

③ Open sales: Generally matching the screw bolt bolt and slot nuts to prevent the effect of bolt and nut loosening. See GB91.

(9)Gear

① Elastic gear: Elastic gear for holes. See GB893; elastic block of the shaft. See GB894 and axis open -ring GB896.

② Steel wire transmission: There are holes in the wire of the steel wire, see GB895.1; the shaft is a steel wire, see GB895.2 and the wire lock ring, see GB921.

③ A shaft parts with a tight transmission ring: there is a gear that is locked in tightly, see GB883; the block locking with screws, see GB884, GB885, etc.

④ Axial transmission ring: The shaft end of the screw tightness, see GB891 and a shaft end gear with bolt bolt, see GB892.

(10) Wood screw

Many varieties are divided into many varieties due to different head shapes and slot types. There are several types of head shapes, hubs, and semi -semi -headed heads. The head grooves are two types: slot (one -word slot) and cross grooves. See GB99-101, GB950-952, etc.