What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
An automatic circlip device discloses an automatic circlip device capable of realizing automatic assembly of the circlip to improve production efficiency and reduce labor costs. However, there are problems of low degree of automation and low work efficiency.
The fixing screw proposed by Guangdong Yueluo Hardware Industry Co., Ltd. has a screw body 1, and the axial surface of the screw body 1 is formed with extending screw teeth 6, and the axial surface is a column along the central axis direction of the cylinder of the screw body 1. The body surface has a hemispherical screw tail 7 at the bottom, and a screw head 2 at the top. The upper surface of the screw head 2 is provided with a slot (not shown). The screw body 1 is composed of the upper tapered rod 4 and the lower cylindrical screw 5. The tapered rod 4 is an inverted cone, the diameter of its circular upper surface and the diameter of the screw mounting hole 10. equal. The fixing screw also has a washer 3, the washer 3 is arranged between the screw head 2 and the screw body 1, the lower surface of the cylindrical washer 3 has a number of teeth 8, the teeth 8 are along the The upper surface of the inverted cone of the tapered rod 4 and the edge of the washer 3 are connected to form a straight convex strip 15 extending outward; the convex strip 15 can also be designed in an arc shape. The fixing screws for installation proposed by Guangdong Yueluo Hardware Industry Co., Ltd. can be made of metal materials in one piece. As shown in Figure 3, it is a schematic diagram of the installation of Guangdong Yueluo Hardware Industry Co., Ltd. for PCB board fixing. When installing, first pass the screw body 1 of the fixing screw through the mounting hole 10 and the copper column 11 provided on the PCB board 9, so that the tail 7 of the screw reaches the mounting hole 13 on the casing 12, and then use the tightening tool 14 to insert the screw At the notch on the top of the head, forcefully press the inverted cone design taper rod 4 of the screw body 1 into the mounting hole 10, so that the tail 7 passes through the mounting hole 13. Due to the outer diameter D at the bottom of the taper rod and the screw mounting hole The aperture size of 10 is equal, and the fixing screws are pressed and fixed, so that the PCB board 9 can be automatically corrected in the process of fixing its front, back, left and right deflections, and the accuracy of the installation position of the PCB board 9 can be ensured. As shown in Figure 4, after the fixing screw is screwed into the casing, the washer 3 is fully contacted and pressed on the PCB board 9, and the PCB board 9, the copper column 11 and the casing 12 are firmly connected together without sliding. . The teeth 8 on the washer 3 are in full contact with the surface of the PCB board 9, so that a ground wire path is set up between the PCB board 9 and the casing 13 by the metal fixing screw 1, thereby ensuring that the PCB board 9 is fully grounded , the design of the teeth 14 on the washer 3 also has a non-slip function. The fixing screws for installation designed by Guangdong Yueluo Hardware Industry Co., Ltd. make use of the cooperation, friction and electrical conductivity in the mechanical connection, which fully guarantees the firm installation of the PCB board and the chassis and the good grounding of the PCB board. Moreover, the ellipsoid tail of the fixing screw The surface is relatively smooth, even if the mounting holes are exposed, it will not cause scratches on the hands and desktop. The above is only the embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., and does not limit the scope of Guangdong Yueluo Hardware Industry Co., Ltd., any equivalent structure made by using the contents of the description and drawings of Guangdong Yueluo Hardware Industry Co., Ltd. or etc. Effective process transformation, or direct or indirect application in other related technical fields, are also included in the protection scope of Guangdong Yueluo Hardware Industry Co., Ltd.
1. When the main body is large-scale equipment, accessories need to be installed, such as sight glass, mechanical seal seat, deceleration frame, etc. The stud bolts used at this time, one end is screwed into the main body, and the other end is equipped with nuts after the accessories are installed. , Since the accessories are often disassembled, when the main body and the accessories are directly connected by bolts, the main body threads will be worn or damaged over time, and it is very convenient to use studs to replace them. 2. When the thickness of the connecting body is very large and the bolt length is very long, stud bolts will be used. The purpose of anti-loosening of stud connection In actual work, the external load has vibration, change, high temperature creep of the material, etc., which will reduce the friction force, the positive pressure in the thread pair disappears at a certain moment, and the friction force is zero, thus making the threaded connection loose. , if repeated action, the threaded connection will loosen and fail. Therefore, it is necessary to prevent loosening, otherwise it will affect the normal work and cause accidents.
Bolt: A type of fastener consisting of a head and a screw (a cylinder with an external thread), which needs to be matched with a nut to fasten and connect two parts with through holes. This form of connection is called a bolted connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection. [1] Stud: A type of fastener that has no head and only has external threads on both ends. When connecting, one end of it must be screwed into the part with the internal threaded hole, the other end must pass through the part with the through hole, and then the nut must be screwed on, even if the two parts are tightly connected as a whole. This form of connection is called a stud connection, which is also a detachable connection. It is mainly used for occasions where one of the connected parts is thick, requires a compact structure, or is not suitable for bolt connection due to frequent disassembly. [1] Screw: It is also a type of fastener consisting of a head and a screw. It can be divided into three categories according to the purpose: machine screws, set screws and special-purpose screws. Machine screws are mainly used for a fastened connection between a part with a fixed threaded hole and a part with a through hole, without the need for nut matching (this connection form is called screw connection, which is also a detachable connection; it can also be Cooperate with the nut, it is used for the fast connection between two parts with through holes.) The set screw is mainly used to fix the relative position between the two parts. Special purpose screws, such as eyebolts, are used for hoisting parts. [1] Nuts: with internal threaded holes, generally in the shape of a flat hexagonal column, but also in a flat square column or flat cylindrical shape, with bolts, studs or machine screws, used to fasten and connect two parts, make it a whole. [1] 5. Self-tapping screw: Similar to machine screw, but the thread on the screw is a special thread for self-tapping screw. It is used to fasten and connect two thin metal components to make them a whole. Small holes need to be made in advance on the components. Due to the high hardness of this kind of screw, it can be directly screwed into the hole of the component, so that the Forming a corresponding internal thread [1] 6. Wood screw: It is also similar to a machine screw, but the thread on the screw is a special thread for wood screws, which can be directly screwed into wooden components (or parts) to connect a band through The metal (or non-metallic) part of the hole is fastened to a wooden member. This connection is also a detachable connection. [1] 7. Washers: A type of fastener with an oblate annular shape. It is placed between the supporting surface of the bolt, screw or nut and the surface of the connecting part, which increases the contact surface area of the connected parts, reduces the pressure per unit area and protects the surface of the connected parts from damage; another type of elastic washer, It can also play a role in preventing the nut from loosening. [1] 8. Retaining ring: It is installed in the shaft groove or shaft hole groove of the machine and equipment, and plays the role of preventing the parts on the shaft or the hole from moving left and right. [1] 9. Pins: mainly used for positioning the left and right parts, and some are also used for connecting parts, fixing parts, transmitting power or locking fasteners. [1] 10. Rivet: A type of fastener consisting of a head and a shank, which is used to fasten and connect two parts (or components) with holes to make them a whole. This form of connection is called rivet connection, or riveting for short. It is a non-removable link. Because if the two parts joined together are separated, the rivets on the parts must be broken. [1] 11. Components and connection pairs: Assemblies are a type of fasteners supplied in combination, such as a combination of a certain machine screw (or bolt, self-supplied screw) and a flat washer (or spring washer, lock washer); Connection pair refers to a type of fastener that is supplied by a combination of special bolts, nuts and washers, such as high-strength hexagon head bolt connection pairs for steel structures. [1] 12. Welding nail: a heterogeneous fastener composed of a nail rod and a nail head (or no nail head), which is fixed to a part (or component) by welding, so as to be connected with other parts. .
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