What is the common fit of a reamed hole bolt to a hole?

The reamed hole bolt is the same as the basic size of the hole, forTransition fits, rather than a gap fit.

When there is relative sliding between the connected parts, the shear resistance of the bolt itself is relied on to prevent its movement, so only a small preload is required.

hinged holes, i.e., hinged hole bolts; Ordinary holes, i.e., ordinary hole bolts.

The differences between the two are:

The unthreaded part of the reamed hole bolt is the same as the basic size of the hole wall and belongs to the fit; The unthreaded part of the ordinary bolt is different from the basic size of the hole wall and does not belong to the fit. On the drawing, it is the reamed hole bolt and the hole wall are composed of a line.

The ordinary bolt and the hole wall are composed of two lines. A hinged hole bolted connection, where the diameter of the screw section is the same as the basic size between the holes, is a transition fit (not a gap fit). When there is a relative sliding between the connected parts, the shear resistance of the bolt itself prevents its movement, so only a small preload is required.

The common fit between the reamed hole bolt and the hole is the base shaft system, the base hole system or the non-reference system.

The fit between the reamed hole bolt and the screw hole is generally a transition fit or interference fit.

The standard hinged hole bolt unthreaded part of the rod diameter DS is 1mm (below m30) or 2mm larger (m30 and below) than the nominal diameter of the thread, if not indicated, the tolerance of the standard hinged hole bolt unthreaded part of the rod diameter ds is h9. Commonly used fits are selected according to the transition fit of the H9 base shaft system to select the tolerance of the hole.

The tolerance of the rod diameter DS of the unthreaded part of the standard reamed hole bolt can also be manufactured in M6 or U8, but it should be indicated in the marking, such as M12M6 80. Commonly used fits are base hole transition fits or interference fits, such as H7 M6, H8 U8.

In the maintenance process, sometimes when replacing the hinged hole bolt, the bolt hole dislocation is relatively large, first according to the situation the hole hinge smooth, the size of the hole at this time and the non-threaded part of the standard hinged hole bolt rod diameter DS is quite different, then according to the size and deviation of the hole using the non-standard hinged hole bolt according to the transition fit or interference fit.

GB T 27-1988 "Bolts for Hexagon Head Hinged Holes Class A and B" has been replaced by GB T 27-2013 "Hexagon Head Reinforcing Rod Bolts", therefore, the hinged hole bolts are now called reinforcing rod bolts.

The difference between bolts for reaming holes and ordinary bolts is whether they belong to fit, different functions, and different working principles.

1. Whether it belongs to the fit: the unthreaded part of the reamed hole bolt is the same as the basic size of the hole wall, which belongs to the fit; The unthreaded part of the ordinary bolt is different from the basic size of the hole wall and does not belong to the fit. On the drawing, it is the reamed hole bolt and the hole wall are composed of a line. The ordinary bolt and the hole wall are composed of two lines.

2. Different functions: The bolted connection of the reamed hole is not just fastening. There is also a positioning function, and ordinary bolt connections are mainly fastened.

3. The working principle is different

1) Hinged hole bolt connection, the diameter of the screw part is the same as the basic size between the hole, is a transition fit (not a gap fit), when there is a relative sliding between the connected parts, rely on the shear resistance of the bolt itself to prevent its movement, so only a small preload is required;

2) The basic size between the diameter of the screw part of the ordinary bolt and its hole is generally different, (the general hole size is one millimeter larger than the bolt size), so it cannot be called a fit. It relies on the preload of the bolt to prevent the relative sliding and movement of the connected parts. When there is a relative sliding between the connected parts, the preload is converted into friction and prevents its movement, so a large preload is required.

Application of bolts:

Bolts are indispensable in daily life and industrial manufacturing, and bolts are also known as industrial rice. It can be seen that the use of bolts is extensive. The application range of bolts is as follows:

Electronic products, mechanical products, digital products, power equipment, mechanical and electrical mechanical products. Bolts are also used in ships, vehicles, hydraulic projects, and even chemical experiments. Anyway, there are a lot of places where bolts are used.

Such as the precision bolts used in digital products. miniature bolts used in cameras, glasses, clocks, electronics, etc.; General bolts for televisions, electrical products, musical instruments, furniture, etc.

As for engineering, construction, and bridges, large bolts and nuts are used; Transportation equipment, airplanes, trains, automobiles, etc., are used with both large and small bolts. Bolts have an important task in industry, and as long as there is industry on the earth, the function of bolts will always be important.

Summary. Ordinary bolts can bear transverse and axial loads, but the transverse load-bearing method mainly relies on the friction brought by the preload moment, and the hinged hole bolt can also bear transverse and axial loads, and the transverse load bearing method depends on the shear strength of the bolt itself, its transverse bearing capacity is much higher than that of ordinary bolts, and the axial bearing capacity is the same as that of ordinary bolts.

What are the characteristics of bolted connections for reamed holes? What kind of load is it used to bear.

Ordinary bolts can bear the transverse and axial loads of the cavity hall, but the transverse load bearing method mainly depends on the friction brought by the preload moment, and the hinged hole bolt can also bear the transverse and axial loads, and the transverse load bearing method depends on the shear strength of the bolt itself, and its transverse bearing capacity is much higher than that of ordinary bolts, and the axial bearing capacity is the same as that of ordinary bolts.

The reamed hole bolt connection, the diameter of the screw part is the same as the basic size between the hole, and it is a transition fit (not a gap fit). When there is a relative sliding between the connected parts, the shear resistance of the bolt itself is relied on to prevent its movement, so only a smaller preload is required. It's a matter of course.

Application example of reamed hole bolts: For structures that use friction to transmit force under vibration load conditions, hinged hole bolts should be used (depending on the shape of the part to transmit force).

A reamed hole bolt is a type of hardware. The function is that the front end thread plays the role of connection, and the rear end does not have a thread to play the role of positioning.

This is the basic logical relationship of the orange bush in the mechanical aspect (more deeply, it is also related to the force and structural design.

The free tolerance is related):

The first bolt specifications selected are standard specifications: M4, M5, M6, M8, M10, M12, (M14), M16 equal width cherry, etc.

Secondly, the other party leaves a hole, the bolt you choose must be smaller than the hole, the other party leaves a hole of 14, you can only choose a bolt less than 14, according to the specifications the nearest only M12. So that's your only option.

Of course, you can also choose M10 or M8 bolts if you meet your mechanics, but you can check whether the bolt spring gasket of M10 or M8 cannot be completely larger than the flange hole and cannot fully function. This is called unreasonable structure. In layman's terms, the hole does not match the bolt.

General mechanical design.

The structural relationship of the hole is one level larger than the bolt, and the diameter of the hole is generally 1 to 2 mm larger than the bolt, so that it is easy to assemble.

But there are exceptions, when the bolt is too small and generally less than m6 empty there is a choice of large millimeters. This is also determined according to the free tolerances of the assembly;

There is also a difference between the hole and the bolt complete fit relationship of only one tenth, one hundredth of a millimeter, which is called hinged hole bolt connection;

When the bolt is greater than M20, the hole can also be appropriately relaxed to require a size of 3 mm, and then up to 4 mm. That's generally the case. The main consideration is the convenience of installation and the reduction of installation difficulty.

When bolt holes are in particularly difficult places to install, designers also consider relaxing the requirements. In the case of a particularly large number of bolts, the requirements will also be relaxed.

Experience and design requirements dictate these, and you'll understand them over time.

Simple questions are harder, I don't know if you can understand?

1) The stress of ordinary bolt connection: the tension force generated by the bolt by the preload or the axial load disturbed by the sock: in addition, the bolt head and the thread are also affected by friction;

2) The selling denier force of the bolt connection of the hinged hole: the part of the bolt rod in contact with the hole wall of the connected piece is subjected to extrusion force, and the bolt rod is subjected to shear force when it is jointed.