BG112346A - 3d printed joint between shaft and a unit - Google Patents

Abstract

The invention relates to a machine element - a shaft or axle connection with a unit, as at least one of the two core elements is obtained after printing with a 3D printer. Because of the complex shape of the surface, the hole cannot be produced with the conventional technology. Attachments such as washers, sprockets, levers, etc. may be attached to the shaft. It can find application in modelling, prototyping and production of 3D printer mechanisms. The 3D printed joint between a shaft and a unit comprises a shaft (1) and a unit (2) joined together by a closed surface (3) formed between a circle (4) and a closed planar shape (5) and the transition from the circle (4) to the figure (5) is smooth. The planar figure (5) may be a regular polygon with rounded tops and can lie in a plane parallel to the circle (4), and the centre of the right polygon (5) coincides with the centre of the circle (4).

Description

3D PRINTED JOINT BETWEEN SHAFT AND LINK

FIELD OF THE INVENTION

The invention relates to a machine element - connection of a shaft or an axis with a unit, as at least one of the two main elements is obtained after printing with a 3D printer. Due to the complex shape of the surface, the hole cannot be made with conventional technologies. The joint can be detachable or non-detachable, transmitting or not torque. Elements such as washers, gears, levers, etc. can be attached to the shaft. It is used in modeling, prototyping and production of mechanisms with a 3D printer.

BACKGROUND OF THE INVENTION

An axial connecting front structure is known, comprising a drive shaft, a drive shaft and a clutch, which are interconnected by profile surfaces, holes in the drive and drive shafts and convex surfaces in the clutch. For example, the holes can have a square and hexagonal profile and a prismatic shape. The cross section of the joint is constant and can be triangular, hexagonal or elliptical in shape. Restrictive face surfaces are used to prevent axial displacement. The structure serves to transmit torque from the drives to the drive shaft [1].

A disadvantage of the axially connecting front structure [1] is that there is a sharp transition in the drive and drive shafts and the clutch from a circuit to a prismatic or other shape, which leads to a concentration of stresses during torque transmission.

A disadvantage of [1] is also that it is difficult to achieve good alignment between the drive and the drive element, because it is necessary to very precisely position the profile section relative to the center of rotation of the shaft.

A disadvantage of the axially connecting front structure [1] is that even with a small inaccuracy in the construction of the three main elements, gaps occur, which affect the transmitted motion and reduce the reliability of the structure.

TECHNICAL ESSENCE

The object of the invention is to create a connection between a shaft and a unit of a mechanism with the following properties: absence of voltage sources; good self-centering; lack of deadlock and silent transmission. The driven unit must be positioned unambiguously towards the shaft and / or have the possibility to step change its orientation towards the shaft. The connection can be made with a 3D printer and used in the modeling and prototyping of robot mechanisms.

This problem is solved by a 3D printed connection between a shaft and a unit, consisting of a shaft and a unit connected to each other by means of a closed connecting surface, which is formed between a circle and a closed planar figure other than a circle, the transition from the circle to the closed plane figure smooth.

A closed plane figure can be a regular polygon with rounded vertices and be located in a plane parallel to the plane of the circle, and the center of the regular polygon is coaxial with the center of the circle. The connection is secured and clamped axially by means of a screw.

The advantage of 3D printing a joint between a shaft and a unit is that the connecting surfaces of the shaft and the unit have smooth and smooth transitions, which leads to very small concentrations of stress in the elements during torque transmission.

The advantage of 3D printing a joint between a shaft and a link is that a good centering between the two elements is obtained, which is due to the inclined sections of the smooth transitions, which are axially symmetrical.

An advantage of the 3D printed connection between shaft and link is that the connection between the elements is tight without gaps and there is no deadlock.

As an advantage of the 3D printed connection between shaft and link, compared to conventional joints, it can be considered that the technology for the production of its elements is simplified. It is produced directly from a 3D CAD model, without the need for 2D documentation.

DESCRIPTION OF THE ATTACHED FIGURES

Fig. 1 - General view of the 3D printed connection between shaft and unit - a) and basic dimensions - b);

Fig. 2 - Various variants of the compound;

Fig. 3 - Application of the joint in a 3D printed model of a walking robot. The connection connects the shaft (1) with a link (2) - a robot leg;

EXAMPLE OF IMPLEMENTATION

3D welded joint between a shaft and a unit consisting of a shaft (1) and a unit (2) connected to each other by means of a closed connection surface (3), such that it is formed between a circle (4) and a closed plane figure (5) different from a circle, the transition from the circle (4) to the figure (5) is smooth. The plane figure (5) can be a regular polygon with rounded vertices and is located in a plane parallel to the circle (4), and the center of the regular polygon (5) is coaxial with the center of the circle (4). The connection is secured and clamped axially by means of a screw (6). (Figure 1 and Figure 3)

The unit (2) is made with 3D printing technology. Due to the complex shape of the surface of the hole can not be made with conventional technologies. Shaft 1 can be obtained from a machine with digital program control or again with 3D printing.

The action of the 3D printed connection between the shaft and the unit consists in the fixed connection of the unit (2) to the shaft (1) by means of the surface (3). It is possible to transmit torque from the shaft (1) to the unit (2) and vice versa.

Depending on the proportions of dimensions D, d and L of the surface (3) which transmits torque (Fig. 1), the joint can be obtained detachable or non-detachable. D is the diameter of the shaft - the circle (4); d is the diameter of the circumscribed circle around the regular polygon (5); L - length of the joint, ie the distance between the plane of the circle (4) and the plane of the polygon (5). When it is detachable, it is necessary to provide axial fixation, for example by means of a screw (6).

Fig. 2a-y shows different embodiments of the contact surface (3) according to claim 1. Fig. 2a) - the planar figure (5) is composed of arcs, fig. 2b) transition from a circle to an ellipse, fig. 2c ) - the plane figure (5) is composed of an arc and a segment.

Fig. 2 e-g show variants according to claim 2. Equilateral triangle, square and pentagon with roundings, respectively. In these variants, it is possible to rotate the unit (2) in steps of the shaft (1).

Variants a-g are suitable for shaft ends, but can still be used in internal steps.

A variant in which the diameter d of the circumscribed circle around the polygon is greater than the diameter D of the shaft is given in Fig. 211.

LITERATURE

1. Patent CN204729487.

Claims (3)

1) 3D printing connection between a shaft and a unit consisting of a shaft (1) and a unit (2) connected to each other by means of a closed connection surface (3), CHARACTERIZED in that the connection surface (3) is formed between a circle 4) and a closed planar figure (5) other than a circle, the transition from the circle (4) to the figure (5) being smooth. 2) 3D printing connection between shaft and unit according to claim 1), CHARACTERIZED in that the plane figure (5) is a regular polygon with rounded vertices, and is located in a plane parallel to the circle (4) and the center of the regular polygon (5) is coaxial with the center of the circle (4). 3D printing 3D connection between a shaft and a unit according to claim 1) or 1) and 2), CHARACTERIZED in that it is provided and pressed axially by means of a screw (6).