Hitachi Construction Machinery Co., Ltd.

Takashi Niidome

Takeshi Kobayashi

Yutaka Komaru

Hitoshi Kagiwada

Yoshitomo Yabuuchi

Naoyuki Okuno

Kazuhiro Numaguchi

Takahiro Tsubo

A plurality of rotating side brake disks and a plurality of non-rotating side brake disks are arranged outside in the radial direction from a motor shaft in a brake case while alternately overlapping with each other. A frictional material is provided on the non-rotating side brake disk, and an oil groove is provided in a frictional engaging surface of this frictional material. It is configured such that, when a braking force is applied by a brake piston to the motor shaft, lubricant oil flowing into the brake case from a lubricant oil inlet port flows from the outer diameter side to the inner diameter side between the rotating side brake disk and the non-rotating side brake disk only through the oil groove. As a result, the lubricant oil having flowed into the brake case efficiently cools the frictional engaging surface.

Wet brake device

An electric motor is arranged on a reduction device, and a wet braking device which gives braking force to a motor shaft is arranged on an upper end side of the electric motor. The wet braking device has a brake case which accommodates an upper end portion of the motor shaft, an adapter which is detachably disposed to the motor shaft in the brake case, a plurality of rotating side brake disks and a plurality of non-rotating side brake disks arranged on an outer peripheral side of the adapter and a brake piston which gives braking force to the motor shaft by frictionally engaging the rotating side brake disks and the non-rotating side brake disks with each other. At the time of performing a maintenance operation for the wet braking device, the wet braking device alone can be solely removed while keeping the electric motor assembled to the reduction device.

Revolving apparatus for construction machine

A motion converting section () and a translation bar () of a feedback mechanism () are provided between a lateral side of a swash plate () and a control sleeve () of a regulator (). When the swash plate () is in a neutral position, the motion converting section () is located in an initial position (F&#x2014;F) at one end of axial direction along an axis line (O&#x2014;O) passing through a tilting center (C) of tilting motions, and, when the swash plate () is driven to tilt in a forward or reverse direction, displaced to the other end of axial direction along the axis line (O&#x2014;O) to convert a tilting motion of the swash plate () into an axial displacement. Through the translation bar (), the axial displacement is transmitted to the control sleeve () of the regulator () as an axial displacement.

Inclined rotation control device of variable displacement hydraulic pump

A volume control valve for controlling the volume of a variable displacement type hydraulic rotary machine includes a valve housing provided with a bore in which a spool slides axially to selectively establish and block communication of a pressure oil feed/discharge port with a high pressure port and a tank port. A first pressure receiving portion is formed in the spool to receive a load pressure as a pilot pressure introduced from a pilot port for displacing the spool axially within the bore. A bottomed axial bore is formed in the spool which has a slidable piston therein defining an oil chamber between the piston end and the bottom of the bore to receive a hydraulic reaction force induced within the oil chamber. A second pressure receiving portion is formed by the bottom of the bore to receive an internal pressure of the oil chamber, thereby changing a total pressure receiving area of the spool in conjunction with the first pressure receiving portion. An oil passage is formed in the spool at a position corresponding to the oil chamber.

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Tsuchiura, Japan

Takashi Niidome