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.

1 . A drum rotating apparatus for use on a construction machine, characterized by the provision of:
 a support member of a tubular shape, open at one axial end and closed with a lid portion at the other axial end thereof, said support member being securely fixed on a basis of a construction machine;   an electric motor located at one axial end of said support member, said electric motor having an output shaft extended axially toward said support member and being connected to an external power supply to rotate said output shaft;   a drum member of a tubular shape, open at one axial end and closed at the other axial end thereof, said drum member being rotatably supported on outer periphery of said support member at one axial end through bearings;   a reduction gear mechanism immersed in a lubricant oil within said drum member, said reduction gear mechanism having a single or multiple reduction stages to rotate said drum member at a reduced speed;   a coupling shaft extended axially in and through said support member, said coupling shaft having one axial end connected to said output shaft of said electric motor and the other axial end rotatably supported in said lid portion of said support member and coupled with said reduction gear mechanism;   a negative type dry electromagnetic brake accommodated in said support member to apply the brakes to said coupling shaft when said electric motor is at rest and take off the brakes to said coupling shaft when said electric motor is in rotation;   a first seal member forming a liquid tight seal between said support member and an opening at one axial end of said drum member; and   a second seal member forming a liquid tight seal between said lid portion of said support member and said coupling shaft; and   a couple of said dry electromagnetic brakes are provided in spaced positions in the axial direction of said coupling shaft.   
   
   
       2 . (canceled) 
   
   
       3 . A drum rotating apparatus for use on a construction machine as defined in  claim 1 , wherein a couple of said dry electromagnetic brakes are adapted to be assembled into said support member commonly in the same direction toward said lid portion through and from the side of an opening at one axial end of said support member. 
   
   
       4 . A drum rotating apparatus for use on a construction machine as defined in  claim 1 , wherein said coupling shaft is composed of a coupling having one axial end connected to said output shaft of said electric motor and provided with a spline on the outer periphery thereof, and an input shaft having one axial end thereof connected to said coupling and the other axial end connected to said reduction gear mechanism;
 said dry electromagnetic brake being comprised of a rotatable disc meshed with said spline of said coupling for rotation therewith, an non-rotatable disc adapted to be brought into and out of frictional engagement with said rotatable disc by a displacement in an axial direction of said coupling, and an electromagnetic coil excited by a power supply from outside to disengage said non-rotatable disc from said rotatable disc.   
   
   
       5 . A drum rotating apparatus for use on a construction machine as defined in  claim 1 , further comprising a connector accommodation room provided upward of said dry electromagnetic brake within said support member fixed on said basis, and a connector mounted in said connector accommodation room to connect external wiring to internal wiring leading to said dry electromagnetic brake. 
   
   
       6 . A drum rotating apparatus for use on a construction machine as defined in  claim 1 , wherein said basis constitutes a truck frame of a crawler type lower structure of said construction machine, said drum member is provided with a sprocket fixedly on the outer periphery thereof for meshing engagement with a crawler belt, and both of said electric motor and said reduction gear mechanism are located within a width of said crawler belt in transverse direction.