Cooling of hydraulic system for vibrating compactor

Abstract: The purpose of the present invention is to cool the hydraulic fluid in a hydraulic-powered vibrating compactor by providing the hydraulic pump (6) of the compactor with a through shaft with a fan wheel (7) mounted on the free end (8), which fan wheel is located so as to draw cooling air (15) through a duct (10) formed by a tunnel-shaped hydraulic fluid reservoir (9).

Description: The present invention relates to achieving efficient cooling of the hydraulic fluid in a hydraulic-powered vibrating compactor, as disclosed in DE 298 01 032 U. With a hydraulic drive, heat is generated in the hydraulic system due to pressure losses. Known methods of cooling the hydraulic fluid are to equip the system with a sufficiently big hydraulic fluid reservoir or to install a conventional oil cooler. However, small compactors in particular precl ude the first of these options, while an oil cooler is both bulky and expensive. The purpose of the present invention is to provide hydraulic-powered vibrating compactors with efficient means of cooling the hydraulic fluid in a simple and economically advantageous manner, particularly since the feasibility of using conventional cooling methods is limited by the size of the machine. Another purpose is to permit the use of environmentally compatible biofluids which, as is known, cannot withstand high temperatures. This is achieved according to the patent claim by designing the fluid reservoir in the shape of a tunnel and providing the hydraulic pump with a through shaft with a fan wheel mounted at one end. Installed in the duct formed by the tunnel-shaped reservoir, the fan wheel generates a flow of cooling air in the duct, which flow is directed further along the top of the reservoir by means of a baffle plate. Practical tests using this arrangement have shown that the fluid temperature is reduced by approximately 30°C and that an operating temperature of approximately 50°C above ambient is achieved, which means that biofluids can also be used. The invention will be described in further detail with the aid of the appended figures, of which Fig. 1 is a longitudinal cross-section through a vibrating compactor and Fig. 2 is a view through section A-A in Fig. 1. In Fig. 1, the sole plate 2 of the vibrating compactor is provided with excentric elements 3 attached to the chassis 1 by means of four vibration dampers 4. The chassis is equipped with an internal combustion engine 5 driving a hydraulic pump 6, which pump is provided with a through shaft with a fan wheel 7 mounted on the free end 8. A hydraulic reservoir 9 is mounted on the chassis. The design of the reservoir is such that its inner side walls 11 form a duct 10, through which the fan wheel draws air. The air is directed upward, with the aid of the baffle plate 12, to the top cover 13 of the compactor casing, passes further across the roof of the hydraulic fluid reservoir 9, and is discharged through the grille in the side 14 of the compactor casing facing the handle 16. The air flow is indicated by the arrows 15 on the figure. The handle grip is designated 17. Fig. 2 is a view through cross-section A-A in Fig. 1 and shows the shape of the hydraulic reservoir 9, the inner side walls 11 of which form the duct 10 in which the hydraulic pump 6 and fan wheel 7 are mounted. The outer side walls of the reservoir are designated 18 and the roof 19.

Claims: Hydraulic-powered vibrating compactor with a device for cooling hydraulic fluid, characterised in that the hydraulic pump (6) of the vibrating compactor is provided with a through shaft with a fan wheel (7) mounted on its free end (8) and is located so as to draw cooling air (15) through a tunnel-shaped hydraulic fluid reservoir (9), which cooling air is then directed upward towards the top cover (13) of the compactor casing, passes further between the said top cover and the roof (19) of the hydraulic fluid reservoir, and is discharged to atmosphere.

Inventors: PERSSON GERT, PERSSON, GERT
Applicants: METSO DYNAPAC AKTIEBOLAG
Application year: 1999
Main classification: E01C19
IPC codes: E02D3, F04D29, E01C19