Technology丨Discussion on the development trend of

The backhoe loader organically combines the digging function of the hydraulic excavator and the loading function of the loader to achieve the function of one machine and two functions. Therefore, it is commonly known as busy at both ends (hereinafter referred to as busy at both ends). It is a kind of construction machinery with a wide range of uses. Used in the construction of municipal, tap water, pipeline gas, electric power, oil field, construction, forestry and other industries.

1 Advantages and disadvantages of excavator loader

The three main features of both ends are as follows: It has the functions of loading and digging. One machine has multiple functions and can be equipped with attachments such as boom, fork, sweeper, breaker, vibratory rammer, etc. It can maneuver quickly and is equipped with a 4-speed or 5-speed hydraulic transmission with a speed of 40km/h.

The shortcomings of the traditional busy side are also obvious, as follows: when loading and excavating, the efficiency is low and the fuel consumption is high, which is far different from the loaders and excavators of equal bucket capacity. The front wheel at the loading end turns, the length of the whole machine is too long, resulting in a large turning radius, and the bucket is not easy to align with the working surface, which is far behind the articulated loader. The digging end cannot be rotated 360° and cannot be moved, which is quite different from the wheel digging. The loading end can only be equipped with unpowered attachments such as booms, forks, and grabs. Powered attachments such as sweepers, vibratory rammers, and snow blowers cannot be equipped. Because the machine cannot move when the excavation side is working, the general user will only install the breaker or use it as a fixed crane. Busy at both ends, telescopic loaders, underground loaders

2 The advantage of the new two-end busy performance

In order to solve the above problems, expand the busy application market at both ends, improve the efficiency of loading and excavation work at both ends, and expand the application of attachments. A new type of busy at both ends is proposed, which is a comparison to the traditional busy frame, excavation work device, and transmission system. , The steering system has been innovatively optimized. Without increasing the cost, the working efficiency of both ends is greatly improved, and the types of attachments that can be used are expanded. The new core technical solution for busy ends: adopting two-way driving technology, hydrostatic transmission technology, four-wheel steering technology, and 230° rotation technology at the excavation end. As shown in Figure 1.

2.1 Two-way driving technology

The new two-headed bus has designed a new control console. The steering mechanism, shift mechanism, accelerator pedal, brake pedal, pilot handle, LCD instrument, function control switch, etc. are all installed on a rotating base to achieve bidirectional driving function. When the digging end is working, it can carry out walking, shifting, reversing, braking and other actions, which are consistent with the wheel digging operation method, with flexible actions and efficient work.

2.2 230° slewing technology at the excavation end

The traditional two-end busy use rotary cylinder to drive the working device to rotate, the rotation angle can only reach 180°, and the working surface is narrow, especially when digging materials and loading the truck, the truck must stop at a certain position on the side of the two busy sides. It is very inconvenient when working in narrow and messy municipal working conditions. When the new two ends are busy facing this kind of working condition, it can be alleviated to some extent. The new two-end busy adopts the working mode of a slewing motor and a slewing bearing, which can achieve a rotation angle of 230°.

2.3 Hydrostatic drive technology

Hydrostatic drive technology is widely used in loaders, but it has not yet been used in the busy side. The new two-end bus adopts single pump + single motor + two-speed gearbox transmission elements, which are divided into working gear and driving gear, which can not only meet the loading work of low speed and high traction, but also meet the high-speed transition work of 38km/h.

2.4 Four-wheel steering technology

The new front and rear axles, both busy at both ends, are steering drive axles. With hydraulic switching valves, three steering modes including two-wheel steering, four-wheel steering and crab steering can be realized, as shown in Figure 5.

When loading, it adopts four-wheel steering and hydrostatic drive technology to become an efficient loader. In high-speed transitions, two-wheel steering is adopted for precise steering and good stability. In special working conditions, the selection of crab steering is adopted to meet the requirements of special terrain and passages.

3 Attachment application expansion

3.1 Loading side

After adopting hydrostatic drive, the loading end can be equipped with not only unpowered attachments such as booms, forks, and grabs, but also power attachments such as sweepers, vibratory rammers, and snow blowers. When power attachments such as sweepers and snow blowers are working, their hydraulic motors must run at full speed to improve work efficiency. This requires that the engine speed must be high in order to drive the hydraulic pump and provide a large flow. But at the same time, the speed of the whole machine must be slow (3 ~ 5km/h) and run at a constant speed, which can only be achieved by hydrostatic drive.

3.2 Digging end

After adopting the two-way driving and 230° slewing technology, when manipulating the excavation end, it is possible to carry out driving, reversing, braking and other actions, which greatly increases flexibility and can perform some actions that could not be completed before. Added the function of applying attachments during travel, which is more convenient and flexible.

4 summary

In order to improve the efficiency of loading and digging work at both ends, and to expand the application of attachments, the traditional busy frame, digging work device, transmission system and steering system have all been innovatively optimized. Without increasing the cost, the working efficiency of the busy side is greatly improved, the types of attachments that can be used are expanded, and the high-speed transition ability is improved.