Why is the shaft made into a stepped shape, and why is the structural design of the shaft generally

Not all shafts are stepped shafts, stepped shafts are because of the mounting of bearings, gears and other accessories, the installation of these accessories needs to separate and fix, all of which need to be made into a stepped shaft.

Because of the stepped shape, it has significant advantages in terms of economy, applicability, and durability.

The stepped shaft machining process is as follows:

1. Blanking: select bar steel according to the diameter size.

2. Breaking material: forging the bar into the first shaft section, the second shaft section, the third shaft section, the fourth shaft section and the fifth shaft section.

3. Preparatory heat treatment: arrange the normalized treatment of the stepped shaft blank after material breaking before cutting.

4. Ensure the size of the end face: then according to the principle of first face and then hole, process the end face first, and mill the key after ensuring the size of the end face.

5. Rough turning: the outer circle of the third axle section of rough turning, taking the left end face of the third axle section as the datum plane, the outer circle of the first axle section and the second axle section of rough turning, turning around and then taking the right end face of the third axle section as the benchmark, rough turning the fourth axle section and the fifth axle section, and then rough turning each retract groove.

6. Quenching and tempering: Quenching and tempering the stepped shaft after rough turning.

7. Semi-finishing car: the first keyway of semi-finishing car, turning around and then taking the outer circle of the third axle section as the benchmark, the fourth axle section and the fifth axle section of semi-finishing turning in turn, and the second keyway of semi-finishing car.

8. Finishing turning: Use the adjustment method to find the top center line as the benchmark, and the finishing turning.

1. The second axle section, the fourth axle section and the fifth axle section of the U-turn fine turn.

9. Turn end face: turn the end face of the stepped shaft.

10. Milling keyway: touch the knife on the surface of the stepped shaft and gently touch the surface of the workpiece to ensure that the keyway is symmetrically distributed according to the centerline.

11. Quenching: surface quenching treatment of the stepped shaft.

12. Grinding the outer circle: use the adjustment method to align the center line as the benchmark, and grind each shaft section of the stepped shaft.

13. Polishing: mirror polishing of the machined stepped shaft.

The role of the stepped shaft

A shaft is a rotating mechanical element, usually of circular cross-section, that utilizes a stepped shoulder to locate mounting parts with different inner diameters, such as gears, bearings, etc. The stepped shaft mainly locates the installed parts, and the shaft shoulders of different heights can limit the movement or movement trend of the parts on the shaft in the direction of the axis line, prevent the slippage of the installed parts in the work, and reduce the influence of the axial pressure generated by some parts in the work on other parts.

The shaft is designed to determine the minimum shaft diameter based on its maximum load-bearing capacity; Determine the fixing mode according to the way of its bearing capacity, select the appropriate bearing, etc., and determine the shaft diameter of the section; According to its fixing mode, determine the appropriate shaft shoulder, etc.; Determination of economical processing dimensions; According to the above characteristics, the entire shaft can be determined, so the size of the shaft diameter may be different, forming the so-called stepped shaft.

The first is to meet the needs of installing different parts on one shaft to meet different transmission functions; The second is to play the role of "locating the source of regret".There are generally some fixed and transmission parts on the shaft, such as gears, bearings, etc., which must be fixed in a certain position, and there is more trouble with interference fitting assembly. If my answer is helpful to you, please give a thumbs up (in the lower left corner), I look forward to your like, your efforts are very important to me, and your support is also the motivation for my progress.

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The rotating shaft as a stepped shaft is mainly for the assembly factor, under the premise of meeting the strength and other requirements, of course, to save materials and reduce costs, and at the same time the inner diameter of the matching bearings, gears and other inner diameters are marked, naturally to make a stepped shaft; The torque of the low-speed shaft is large, and of course the diameter is larger than that of the high-speed shaft.

After the basic module of the rotating shaft is done, it is necessary to start further processing according to the flow chart made in advance to reach a certain level of process.

Rotating shaft of hollow structure: its structure is very simple, easy to produce, and the factor affecting the torque is the interference of the male shaft and the female shaft, but the interference amount shall not be too large within a certain size range, otherwise the structure will be damaged, so it needs a more precise dimensional tolerance to meet the required interference requirements.

For the sake of the torque value of practical application and the convenience of assembly, the solid shaft of the male shaft is removed into a hollow male shaft, so it is called a hollow structure. The strength of the hollow of the structure also has a great influence on the torsional force.

The most important way to control the torque range is to design the interference value and the strength of the hollow of the male shaft to meet the appearance and size needs of the female shaft.

The reason why the hinge is often designed as a stepped structure:

Some parts with hubs are usually installed on the shaft, so most shafts should be made into stepped shafts, and the amount of cutting is large. The length of the shaft is usually specified as the scale size, and the length of each step of the stepped shaft can be given accordingly according to the requirements of the pants.

The outer diameter of the stepped shaft is not the same as that of a round rolled product, the outer diameter of all parts is the same, and the outer diameter size is different for different steps.

Stepped bushings are a method of axial positioning of bearings. Stepped bushings are particularly suitable for precision bearing arrangements and offer less run-out and greater accuracy than threaded lock nuts.

Stepped bushings are often used for very high-speed spindles, for which conventional locking devices do not provide sufficient accuracy.

Expansion of the closed hall materials

1. According to the shape of the shaft, it is divided into: optical axis, stepped axis, solid axis, and hollow axis.

Stepped shaft – a shaft with different outer diameters that form a shoulder.

Shaft wear is the most common equipment problem in the use of shafts. There are many reasons for the wear of shafts, but the main reason is determined by the metal characteristics used to manufacture shafts, although the hardness of the metal is high, but the concession is poor (can not be restored after deformation), the impact resistance is poor, the fatigue resistance is poor, so it is easy to cause adhesive wear, abrasive wear, fatigue wear, fretting wear, etc., most of the shaft wear is not easy to detect.

2. Other methods of axial positioning of bearings.

1) Lock nut positioning method:

When mounting the inner ring of a bearing with an interference fit, one side of the inner ring is usually resting against the shoulder on the shaft and the other side is usually secured with a lock nut (KMT or KMTA series). Bearings with tapered bore are mounted directly on the tapered journal and are usually fixed to the shaft with a lock nut.

2) Spacer positioning method:

It is convenient to use spacers or spacers between bearing rings or between the bearing rings and adjacent parts instead of integral shoulders or housings. In these cases, dimensional and form tolerances are also applied to the bridge in question.

There are generally some fixed and transmission parts such as gears and bearings on the shaft, which must be fixed in a certain position, and there is more trouble to assemble with interference fitting.

Mainly to facilitate the positioning of components on the shaft, such as gears and bearings; In the case of optical axes, tandem movement occurs;

The diameter of each cross-section of the stepped shaft is different to make the strength of each shaft segment similar and to facilitate the installation and fixing of the parts on the shaft.

What is this math problem or a physics problem?

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