Construction machine

Abstract

A construction machine which comprises an undercarriage, an upper structure rotatably mounted on a top of the undercarriage, and a work equipment movably supported at a front of the upper structure, in which within a frame assembly that forms a base of the upper structure, at least following components are produced by casting a weldable material: a work equipment support that supports the work equipment; a right vertical rib and a left vertical rib, a distance therebetween widening gradually as they extend backwards from the work equipment support; a bottom plate that extends towards inside, adjoining bottom edges of the work equipment support, the right vertical rib and the left vertical rib.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a construction machine, and more particularly to a frame assembly that forms the base of an upper structure of a construction machine. [0003] 2. Description of the Related Art [0004] According to Japanese Patent Application Laid-open No. 2002-146834, a backhoe 100 chiefly comprises a lower movement device 102, an upper structure 103, and an excavation device 104 installed on the upper structure 103, as illustrated in FIG. 5, which shows a right side view. [0005] The revolving frame F that forms the base of the upper structure 103 and is provided at the bottom face thereof is equipped with a support 111 on which the excavation device 104 is supported on an axle in such a way as to be able to revolve in a horizontal direction, and is illustrated in FIG. 6, which shows an exploded view. [0006] By the structure described above, operating the excavation device 104 of the backhoe 100 cause...

AI Technical Summary

Benefits of technology

The present invention relates to a construction machine that has an improved load capacity and strength, while also being a reliable and cost-effective machine. The construction machine has a frame assembly with a work equipment support, vertical ribs, and a bottom plate that are produced by casting a weldable material. The use of cast steel and the uniform molding of the rear vertical rib in the cast provide a structure that is even stronger. The construction machine is easy to produce and has a reduced weight and cost of production. Overall, the invention provides a reliable and cost-effective construction machine that is strong and efficient.

Problems solved by technology

Although a revolving frame made from sheet metal according to Japanese Patent Application Laid-open No. 2002-146834 has the advantage of making it possible to restrict any increase in weight by choosing steel plates of the optimum thickness for each part, however, the number of parts is large and there is a problem with high costs caused by the large amount of welding work required to join each of the constituent parts by welding.

This means that stress concentration can easily occur, and this makes it difficult to ensure sufficient strength.

For this reason, in order to form smooth R portions at the connecting parts during joining, with the aim of preventing stress concentrations from occurring when the machine is in operation, it is necessary to carry out packing and grinding in addition to the joining by means of welding, causing extra burdens during the manufacturing process, and leading to an increase in the amount of work required.

However, this method presents disadvantages too.

If the cast is made too thin, this can cause problems with the smooth flowing of the casting material used and cavities can form; depending on the size of the parts, the material may cool before it has properly filled the mold, and yield is poor.

For this reason, one problem associated with cast metal molds is an increase in weight, since these limitations of the manufacturing process make a certain thickness necessary, so that for example a thickness of 25 mm is required where 10 mm would otherwise be sufficient.

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