Development of schematic diagram of accessory for assembly of cr

Contents

Introduction

1. Weldment Analysis

1.1 Base metal weldability analysis

1.2 Analysis of article design

1.3 Structural Shape Analysis of Workpieces

1.4 Analysis of welded joints and welds

2. Development of manhole cover basing scheme

2.1 General provision

2.2 Basing of hatch cover

2.3 Basing of brackets and closures

2.4 Development of site layout

3. Development of schematic diagram of the hatch cover assembly accessory

3.1 Types of supports and places of their installation

3.2 Carbon Dioxide Semiautomatic Welding Modes

3.2.1 Tacks, their dimensions and welding modes for their application

3.3 Types of deformations arising from tack joints

3.4 Determination of workpiece fastening forces

3.5 Selection and arrangement of clamping devices

3.6 Development of schematic diagram of the accessory

Application

Appendix A. Manhole cover. General view

Appendix B. Basing Parts

Appendix B. Site basing

Appendix G. Schematic diagram of the accessory and for the assembly of the car hatch cover

Conclusion

List of used literature

Introduction

In modern conditions of production of welded structures, the products must be competitive and meet the established requirements. In the production of welded structures, not only welding robots are carried out, but also assembly ones - which in turn form a significant part of the labor intensity of the work performed.

One of the methods of solving and facilitating these works in large-scale and mass production is the use of devices. In the design of which you need to solve such issues as:

1. Constructability;

2. development of a site layout;

3. development of a schematic diagram of the accessory.

In this course work, in addition to the development of a schematic diagram of the device for assembling the car hatch cover, issues of processability of welded structures are considered and welding modes are selected in accordance with the type of design and spatial position of welds .

Product Design Analysis

The welded article is a flat structure designed to lock the car wall and consists of a cover (bent sheet with bent edges), two brackets with holes and two seals.

On the outer surface of the cover, the brackets are symmetrically arranged on both sides so that they are installed on the end, and the holes extend beyond the plane of the cover, the most important size is the size between the inner surfaces of the brackets. Seals are installed on inner side of cover and opposite relative to brackets. The required dimensions to be provided are the dimensions from the edge of the cover to the termination axis and the dimension between the closures relative to the axis of symmetry .

The hatch cover drawing is shown in Appendix A.

Panel cover basing

When basing the cover, select the plane with the largest cross-sectional area and issue it as an installation plane. It provides a stable position of immobility in three planes - movement along one coordinate axis and rotations around two other axes (movement along the Z axis and rotations around the X and Y axes). In order to prevent the part from overturning, it is necessary to position the center of gravity of the cover inside the support triangle formed by the three basing points.

To secure the part more securely, you need to apply a guide base that deprives the cover of two more degrees of freedom - movement along one coordinate axis and rotation around another axis (movement along the Y axis and rotation around the Z axis).

To deprive the cover of residual mobility (sixth degree of freedom), it is necessary and sufficient to find such a surface, called a supporting surface, on which by applying a double-sided connection, we deprive the cover of movement along one coordinate axis (along the X axis).

Basing of brackets and closures

Basing of brackets and closures is similar to basing of panel cover (para 2.2).

Detail-based drawings are shown in Appendix B.

Development of site layout

According to the drawing, the manhole cover is selected as the base part. The position of the base part is selected so that the largest number of tacks and welds is made in the lower position.

Manhole cover basing diagram is similar to that given in section 2.2.

The brackets are based on their mutual arrangement with the cover (para 1.2). Since the base part contacts the end face of the bracket, we take the end face as the support base, and the outer surface of the bracket as the guide.

Closures shall be installed in the same manner.

The layout of the node is shown in the drawing (Appendix B).

Development of schematic diagram of the hatch cover assembly accessory

When developing the schematic diagram of the hatch cover assembly device, it is necessary to use installation elements that allow for the correct placement of parts in the device. Two types of supports are used as mounting elements in this case: movable and stationary, since all surfaces of the structure are flat.

When developing the schematic diagram of the beam accessory, it is necessary to select the type, number and places of supports installation. The symbol and types of supports, clamps and mounting elements are given in GOST 3.1107 - 81.

Types of supports and places of their installation

The development of the scheme begins with the installation of the cover. Installation is carried out on fixed supports, which will be located on the most developed plane. Since the length and width of the cover does not exceed 1000 mm, 4 fixed supports will be required for installation.

To make the structure stationary, it is necessary to fix its side surface and end face with fixed supports.

The brackets are installed on an undeveloped plane (on the end), since this is necessary according to the assembly technology (paragraph 1.2). This requires 3 movable supports (two supports on the side surface and one support on the end).

Closures are installed similar to brackets.

The general layout of the supports is shown in the drawing (Appendix D).

Design of arrangement of clamping devices

Clamping devices ensure reliable pressing of blank to mounting elements and prevent displacement of blank during assembly and welding. The forces that secure the workpiece should not cause its movement, which is achieved by symmetrically applying forces or placing them near the supports. Various types of actuators are used to secure the workpiece in the devices, which are divided:

1. mechanical,

2. pneumatic, hydraulic and vacuum,

3. electromechanical, electromagnetic and magnetic,

4. combined.

To avoid non-uniform transverse plastic deformation in thickness, a clamping force value equal to P = 270 N is applied, since it is at this clamping force value that cracks do not occur.

All types of clamping devices are suitable for securing the hatch cover. We choose hydraulic clamps, as they are reliable and efficient in welding production.

In order to eliminate the factors of crack formation from the application of tacks, clamps are installed so that the fixing force is located near the mounting elements. At the same time, under the applied force there must be a support to prevent bending or rotation of the part.

The location of the clamping forces is shown in Appendix G.