Mechanical Drawing (Taking Gear Oil Pump and Pedal as an Example) Course Design Essay Title: Mechanical Drawing Name: Zhang Qin Date: 20 1 0-18 Course Design Training Purpose and Task:1. Master the basic principle and application of orthographic projection method and gear meshing diagram II. Basic ability to draw and read simple mechanical drawings. Cultivate the spatial logical thinking ability of three-dimensional shapes and related positions 4. Understand and learn the new functions of AutoCAD2007, and be familiar with the functions of AutoCAD 2D drawing. With the progress of society and the development of knowledge, the application of engineering drawing is more and more extensive, and engineering drawing is more and more frequent. At the same time, the mapping of engineering samples has become more and more important! After a year of mechanical drawing study, I gradually understand the practicality of mechanical drawing, the importance of drawing part drawings, and the accuracy, clarity, standardization and objectivity that must be achieved in the process of drawing part drawings! Because there are no solid parts, we have to draw the parts according to the sketch. After about half a month's sketch and mapping, I drew the gear oil pump, pedal and pedal in AutoCAD. In the process of drawing the gear oil pump, because there are only parts drawings of the gear oil pump, and I want to draw the assembly drawings of the gear oil pump, I must carefully look at all the dimensions, technical requirements and title bars of each group of drawings, and at the same time, I must pay attention to the section drawings of the assembly drawings, the section drawings of parts, the specified drawings and the simplified drawings. Because there are many parts in the assembly drawing, the expression method of parts is particularly important. In the process of drawing threads, internal threads must be drawn. At this time, the small diameter of internal thread must be drawn with thick solid line, and the large diameter must be drawn with thin solid line. At the same time, when drawing the section line, the section line must be drawn to the thick solid line, that is, the small diameter position of the internal thread; In the process of drawing screws, the large diameter of screws must be drawn with thick solid lines, the small diameter must be drawn with thin solid lines, and the thread termination line must also be drawn with thick solid lines. When the screw is matched with the internal thread, the large-diameter thick solid line and thin solid line of the screw and the internal thread should be aligned respectively, and the section line must be drawn on the thick solid line, and at the same time, it must be marked that the screw meets the processing requirements. In addition, there is an important part in the assembly drawing-gear meshing. The gear meshing in the assembly drawing is a simplified drawing, and the tooth root lines of the two gears in the meshing area must be drawn with thick solid lines. When drawing the tooth top line, the tooth top line of one gear is drawn with thick solid line, the occlusal part of the tooth top line of the other gear is drawn with thin solid line, the tooth top lines of the two gears are drawn with thick solid line, and the scale line is drawn with fine dots. According to the national standard, when the gear is fully sectioned, when the sectioning plane passes through the gear axis, the gear teeth are not sectioned, and the sectioning lines are drawn at other sections of the gear. In my opinion, it is the most important and difficult to draw the assembly drawing of gear oil pump, which should be the drawing of thread and gear meshing mentioned above. However, if you are careful, careful and serious, the difficulty will not be too great. As long as the engagement between the thread and the gear is drawn, the other parts of the assembly drawing can be drawn easily. But don't forget the size, technical requirements, serial number, parts list and title bar of the assembly drawing. The part drawing of pedal frame is easier to draw than the assembly drawing of gear oil pump. In the process of drawing parts, front view, top view and left view must be drawn, and local view must be drawn when necessary to complete the perfect drawing and machining of parts. When drawing the parts of the pedal, you only need to draw the front view and the top view. Although there is only an axonometric drawing of the pedal part drawing, it is easy to draw the part drawing. As long as you can understand the axonometric drawing, especially the top view of the pedal, it is almost the same before, so it is not difficult. The front view is not difficult, just draw a partial view, but pay attention to the transition drawing at the joint of ribs. Finally, remember that, like the assembly drawing, the part drawing of the pedal should also be marked with dimensions and technical requirements. AutoCAD drawing is relatively simple, but we must pay attention to the dimensioning and technical requirements. Through the drawing of this part drawing, assembly drawing and AutoCAD, I have a clearer understanding of the previous mechanical drawing, a fuller understanding of the knowledge I have learned before, and an opportunity to review what I have learned. I have gained a lot. Mechanical drawing is not difficult to draw, as long as we are careful, careful and serious, we can draw it correctly, which provides a strong guarantee for our future processing, production and manufacturing.