Drum rotating apparatus for use on construction machines

Abstract

A support member which is securely fixed to a truck frame is constituted by a tubular body portion and a lid portion. A couple of dry electromagnetic brakes are located in a brake accommodation room within the tubular body portion. The support member is assembled with an electric motor. A drum member which accommodates a planetary reduction gear mechanism is rotatably mounted on the outer periphery of the support member through bearings. A floating seal is provided between the support member and the drum member, and a seal ring (45) is provided between an axial bore in the support member and a coupling shaft. Thus, the two dry electromagnetic brakes are accommodated in the support member, safely shielded from lubricant oil.

Description

TECHNICAL FIELD[0001]This invention relates to a drum rotating apparatus particularly suitable for use in a construction machine, for example, a vehicle drive unit for a hydraulic excavator, a hydraulic crane or a rope winch drum.BACKGROUND ART[0002]Generally, vehicle drive units of construction machines such as hydraulic excavators, wheel loaders and the like employ a drum rotating apparatus for rotating a drum member on which a sprocket is mounted, for driving a crawler belt or for rotating a drum member on which a vehicle wheel is mounted. Also, a drum rotating apparatus is used on a rope winch which is mounted, for example, on a hydraulic crane for winding and unwinding a rope by rotating a drum member (e.g., see, for example, Japanese Patent Laid-Open No. 2000-9017, H1-153840 and S60-183498).[0003]In this instant, the prior art drum rotating apparatuses are largely constituted by a hydraulic motor serving as a drive source, a reducing mechanism which is located on the inner per...

AI Technical Summary

Benefits of technology

[0013]Besides, the dry electromagnetic brake, shielded from the lubricant oil, is accommodated in a compact form within the support member which the electric motor and the reduction gear mechanism are provided, making it possible to compactify the entirety of the drum rotating apparatus incorporating the dry electromagnetic brake.

[0015]By a couple of the dry electromagnetic brakes which are located within the support member, in spaced positions in the axial direction of the coupling shaft, a large braking force can be applied to the coupling shaft, holding the drum member standstill when the electric motor is at rest. In this case, a free heat releasing space can be formed between the two dry electromagnetic brakes. Therefore, heat which is generated as a result of excitation of the dry electromagnetic brakes can be efficiently released into the heat releasing space between the two brakes. This contributes to enhance durability of the dry electromagnetic brakes and reliability of the drum rotating apparatus as well.

[0019]In this manner, the coupling shaft which couples the output shaft of the electric motor with the reduction gear mechanism is constituted by a coupling and an input shaft. Therefore, for example, after connecting the input shaft with the reduction gear mechanism, the input shaft can be easily connected with the output shaft of the electric motor by the coupling. Thus, the output shaft of the electric motor can be coupled with the reduction gear mechanism in an efficient manner.

[0021]With the arrangements just described, even if rain water should get into the support member through an interstice between the support member and the electric motor, the connector can be kept out of contact with rain water to guarantee higher reliability of the electromagnetic brake.

Problems solved by technology

Therefore, there has been a serious problem of pollution of environments by exhaust gases emanated from an engine during a drum rotating apparatus is in operation, in addition to a problem that a working environment is degraded to a considerable degree by operational noises of the engine.

However, in the case of an electric motor-driven drum rotating apparatus having lubricant oil within a drum member along with a reducing mechanism, difficulties are encountered in mounting a negative type dry electromagnetic brake on the inner peripheral side of a drum in a compact form, in a complete shielded state from inflammable lubricant oil.

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