JPH0250574U - - Google Patents

Description

【図面の簡単な説明】[Brief explanation of the drawing]

第１図はこの考案にかかるパイロツト操作チエ
ツク弁のたて断面図、第２図は第１図のＦ部詳細
図、第３図は第１図のＧ―Ｇより見た断面図、第
４図および第５図はそれぞれこの考案のパイロツ
ト操作チエツク弁の作動状態を示すたて断面図、
第６図はパイロツト操作チエツク弁を配置した油
圧回路図、第７図は従来技術パイロツト操作チエ
ツク弁のたて断面図である。 １，４３……パイロツト操作チエツク弁、２…
…作業アタツチメント、３，４……油圧シリンダ
、６……パイロツト切換弁、４４……ケーシング
本体、４６……チエツクバルブ機構、４９……蓋
体、５０……スリーブ筒体、５５……大径溝部。 Fig. 1 is a vertical sectional view of the pilot operated check valve according to this invention, Fig. 2 is a detailed view of section F in Fig. 1, Fig. 3 is a sectional view taken along line GG in Fig. 1, and Fig. 4 is a sectional view of the pilot operated check valve according to this invention. 5 and 5 are vertical sectional views showing the operating state of the pilot operated check valve of this invention, respectively;
FIG. 6 is a hydraulic circuit diagram in which a pilot operated check valve is arranged, and FIG. 7 is a vertical sectional view of a prior art pilot operated check valve. 1,43...Pilot operation check valve, 2...
...Work attachment, 3, 4...Hydraulic cylinder, 6...Pilot switching valve, 44...Casing body, 46...Check valve mechanism, 49...Lid body, 50...Sleeve cylinder body, 55...Large diameter Groove.

Claims (1)

【実用新案登録請求の範囲】[Scope of utility model registration request] 建設機械用作業アタツチメント２に装備した油
圧シリンダ３と、その油圧シリンダ３を制御する
パイロツト切換弁６とを連通する作動回路に、作
業アタツチメント２の自然降下を防止するために
配置したパイロツト操作チエツク弁において、ケ
ーシング本体４４の上部側に上記油圧シリンダ３
のボトム側油室３ａに通じるポートＢ部材４５を
そなえたチエツクバルブ機構４６を固定して設け
、またケーシング本体４４の下部側にポートＡお
よびパイロツト圧導入用ポートＣをそなえた蓋体
４９を固定して設け、また上記ケーシング本体４
４内周面５２と、上記チエツクバルブ機構４６お
よび蓋体４９のそれぞれ円筒部外周面５３，５４
にそつて軸心方向に摺動移動可能なスリーブ筒体
５０を設け、そのスリーブ筒体５０の内周中央部
付近の位置に全周にわたつてそのスリーブ筒体５
０の内径寸法より大径の大径溝部５５を形成し、
その大径溝部５５の上側傾斜段付部５６とチエツ
クバルブ機構４６下部外周との密接するシート部
５７を設け、油圧シリンダ３制御用パイロツト切
換弁６が中立位置のときにはチエツクバルブ機構
４６およびスリーブ筒体５０がそれぞれシート部
５８，５７を閉じてポートＢよりポートＡに通じ
る油路を遮断可能とするとともに、ポートＣにパ
イロツト圧が作用したときまたはポートＢにオー
バロード圧が導入されたときスリーブ筒体５０を
上方へ移動し、その大径溝部５５内シート部５７
を開口可能に構成したことを特徴とするパイロツ
ト操作チエツク弁の構造。 A pilot operation check valve is provided in an operating circuit that communicates between a hydraulic cylinder 3 installed on a work attachment 2 for construction machinery and a pilot switching valve 6 that controls the hydraulic cylinder 3 in order to prevent the work attachment 2 from falling naturally. , the hydraulic cylinder 3 is installed on the upper side of the casing body 44.
A check valve mechanism 46 having a port B member 45 communicating with the bottom side oil chamber 3a is fixedly provided, and a lid body 49 having a port A and a port C for pilot pressure introduction is fixed to the lower side of the casing body 44. and the casing body 4
4 inner circumferential surface 52, and outer circumferential surfaces 53, 54 of the cylindrical portion of the check valve mechanism 46 and lid body 49, respectively.
A sleeve cylindrical body 50 is provided that is slidable in the axial direction along the sleeve cylindrical body 50, and the sleeve cylindrical body 50 is provided at a position near the center of the inner circumference of the sleeve cylindrical body 50 over the entire circumference.
forming a large diameter groove portion 55 having a larger diameter than the inner diameter dimension of 0;
A seat portion 57 is provided in which the upper inclined stepped portion 56 of the large diameter groove portion 55 and the lower outer periphery of the check valve mechanism 46 are in close contact with each other, so that when the pilot switching valve 6 for controlling the hydraulic cylinder 3 is in the neutral position, the check valve mechanism 46 and the sleeve cylinder The sleeve 50 closes the seat portions 58 and 57, respectively, and can shut off the oil passage leading from port B to port A, and when pilot pressure acts on port C or overload pressure is introduced into port B. Move the cylindrical body 50 upward and insert the seat portion 57 inside the large diameter groove 55.
A structure of a pilot-operated check valve characterized by being configured such that it can be opened.