JPH0482059U

JPH0482059U -

Info

Publication number: JPH0482059U
Application number: JP12487390U
Authority: JP
Priority date: 1990-11-26
Filing date: 1990-11-26
Publication date: 1992-07-16

Description

[Brief explanation of the drawing]

第１図は本考案の一実施例を示す掘削機のシー
ケンス制御油圧回路の構成図、第２図は本考案の
他の実施例を示す第１図と同状図、第３図は従来
の掘削機の要部構成図、第４図は同掘削機のシー
ケンス制御油圧回路構成図である。１……掘削機本体、２……第１ブーム、３……
第２ブーム、４……アーム、５……バケツト、６
……第１ブームシリンダ、７……第２ブームシリ
ンダ、７ｂ……ロツド側、８……アームシリンダ
、８ａ……ボトム側、９……バケツトシリンダ、
９ａ……ボトム側、４５……第５（第２ブームシ
リンダのロツド側）リリーフ弁、４６……第６（
バケツトシリンダのボトム側）リリーフ弁、４８
……第８（アームシリンダのボトム側）リリーフ
弁、５３……第５（第５リリーフ弁の）パイロツ
ト圧力管路、５８，５８′……連結管路。 Fig. 1 is a block diagram of a sequence control hydraulic circuit for an excavator showing one embodiment of the present invention, Fig. 2 is a diagram similar to Fig. 1 showing another embodiment of the present invention, and Fig. 3 is a diagram of a conventional hydraulic circuit. FIG. 4 is a block diagram of the main parts of the excavator, and FIG. 4 is a block diagram of the sequence control hydraulic circuit of the excavator. 1... Excavator main body, 2... First boom, 3...
2nd boom, 4...arm, 5...bucket, 6
...First boom cylinder, 7...Second boom cylinder, 7b...Rod side, 8...Arm cylinder, 8a...Bottom side, 9...Bucket cylinder,
9a...Bottom side, 45...Fifth (rod side of the second boom cylinder) relief valve, 46...Sixth (
Bottom side of bucket cylinder) Relief valve, 48
...Eighth (bottom side of the arm cylinder) relief valve, 53...Fifth (of the fifth relief valve) pilot pressure line, 58, 58'...Connection line.

Claims

[Scope of utility model registration request]

A first boom rotatably attached to the excavator body, a second boom rotatably attached to the first boom, an arm rotatably attached to the second boom, and this arm. An excavator equipped with a bucket rotatably attached to a bucket, and first and second boom cylinders, arm cylinders, and bucket cylinders that control the rotation of the first and second booms, arms, and bucket, respectively. In the machine, the pilot pressure line of the rod-side relief valve of the second boom cylinder and the pilot pressure line of the bottom-side relief valve of either the bucket cylinder or the arm cylinder are connected to each other by a connecting line. An excavator characterized in that the relief pressure on the rod side of the second boom cylinder is set higher than the relief pressure on the bottom side of either the bucket cylinder or the arm cylinder.