Hitachi Construction Machinery Co., Ltd.

Takayoshi Murahashi

Toshikazu Minoshima

Takao Kurosawa

Isamu Aoki

Masaki Yoshikawa

Takashi Yagyu

Yutaka Watanabe

Michio Fushiki

Yoshifumi Nabeshima

Koji Shimazaki

Tomohiro Ueda

Hajimu Kozawa

Masakazu Kaitou

Osamu Murakami

Kenji Itoh

Takashi Ishii

Takashi Tateyama

In an unloaded state of the bucket (), a control device () calculates an unloaded moment (M) around a hinge pin G from the pressure of the lift arm cylinder that is detected by pressure sensors (), the angle of a lift arm that is detected by a lift arm angle sensor, and dimension data extracted from a vehicle body information database (). In a loaded state of the bucket, the control device calculates a loaded moment (M) around the hinge pin G from the pressure of the lift arm cylinder, the angle of the lift arm, and the dimension data extracted from the vehicle body information database. The control device calculates the load (W) on the bucket by dividing the difference between the unloaded moment and the loaded moment by the horizontal distance (L) between the hinge pin and the gravity center position of the bucket.

Wheel loader and bucket load calculation method

When the drive of a lubricant pump () is stopped to prevent the lubricant pump () from assuming an idling state, a determination is made as to whether or not a temperature difference (&#x394;T) between the temperature (T) of a lubricant oil detected earlier by a temperature sensor () and a warning temperature (Toh) is equal to or lower than a predetermined threshold value (&#x3b1;). When the temperature difference (&#x394;T) is within the threshold value (&#x3b1;), an 'overheat' warning is issued to an operator of a dump truck (). In consequence, even in a case where a temperature sensor () is provided on the output side of the lubricant pump () by being located on an outer side of a wheel mounting case (), planetary gear reduction mechanisms (), () inside the wheel mounting case () can be prevented from overheating by warning the operator of the vehicle.

Lubricant oil state warning device for a working vehicle

In case a temperature (T) of a lubricant oil (G) cannot be detected by an oil temperature sensor () provided on an output side of a lubricant pump (), the temperature (Tm) of a wheel drive motor () is detected by using a motor temperature sensor () provided on the wheel drive motor (). By estimating the temperature (T) of the lubricant oil (G) from the temperature (Tm) of the wheel drive motor (), monitoring is carried out as to whether or not the temperature (Tm) has risen to a predetermined temperature (Tms) at which the cooling of the lubricant oil (G) by forced circulation is deemed necessary. The drive of a lubricant pump () by a pump drive motor () is stopped until the motor temperature (Tm) rises to a level exceeding the predetermined temperature (Tms).

Travel drive apparatus for a working vehicle

A lubricant circulation pump () which is driven by an electric motor () is provided in the course of a circulation path (A,B) for circulating lubricant oil to a wheel mounting case () which is rotated together with a rear wheel (). Turning on and off the lubricant circulation pump is controlled according to rotational speed of the rear wheel. When lubricant oil in the wheel mounting case sticks on inner peripheral surfaces thereof under the influence of centrifugal force as a result of the increased vehicle speed, the electric motor is turned off to suspend operation of the lubricant circulation pump. Consequently, the lubricant circulation pump does not suck lubricant oil in the wheel mounting case through an inlet opening (A) of an intake pipe (), thereby preventing the lubricant circulation pump from being put in a dry idling operation.

Traveling drive unit for working vehicle

The present invention provides a traveling speed reduction gear lubricating oil cooling device that enables optimal temperature control for lubricating oil delivered via a lubricating oil pump that can be started up with a relatively small motor without running the risk of damage to an oil cooler in a cold work environment even when a temperature sensor that detects the temperature of the lubricating oil is installed outside a wheel mounting sleeve. During a startup operation, provided that the detected temperature at a traveling motor is higher than the reference temperature, the lubricating oil pump is driven at a speed in a lower speed range relative to the normal operation speed range. In addition, during the startup operation, the rotation speed of the drive motor for the lubricating oil pump is increased in correspondence to a rise in the temperature detected by a lubricating oil temperature detection sensor.

Lubricating oil cooling device for traveling speed reduction gear

A traveling speed reduction gear lubricating oil cooling device has a temperature sensor for detecting the temperature of lubricating oil to be installed outside a wheel mounting sleeve without running the risk of damage to a lubricating oil pump in a cold work environment. A startup operation reference speed lower than a reference speed for normal operation is set so as to ensure that air intake does not occur. A startup operation comparison device compares the speed detected by a speed sensor with the startup operation reference speed. If the detected speed is lower than the startup operation reference speed, a drive motor for the lubricating oil pump is engaged in operation at a speed lower than a normal operation speed. If the detected speed is higher than the startup operation reference speed, the drive motor for the lubricating oil pump is turned off.

An upper cross beamfor supporting a rear side of a cabfrom below is formed as a separate member from a base frame. This upper cross beamis separably mounted on left and right column portionsE of the base frameby using bolts. Namely, when an engineis mounted to the base frame, the upper cross beamis separated in advance from the base frame. Consequently, at the time of the operation of carrying in the engine, it merely suffices to vertically hoist or lower the engineby use of a crane. It is thereby possible to carry in the enginebetween the column portionsE of the base framewithout being hampered by the upper cross beam

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Tsuchiura, Japan

Takayoshi Murahashi