CN-121976980-A - Hydraulic system for excavator, valve structure and engineering machinery

CN121976980ACN 121976980 ACN121976980 ACN 121976980ACN-121976980-A

Abstract

The invention relates to the technical field of engineering machinery, and particularly discloses a hydraulic system for an excavator, a valve structure and engineering machinery. The output end of the back pressure valve is communicated with the oil tank, the first movable arm valve comprises a first port a, a second port a and a third port a, the first port a is used for being communicated with a movable arm rod cavity of the movable arm cylinder, the second port a is used for being communicated with a movable arm rod-free cavity of the movable arm cylinder, the third port a is communicated with the input end of the back pressure valve, when a valve core of the first movable arm valve is in a floating position, the first port a, the second port a and the third port a are mutually communicated, and an oil supplementing oil way is communicated with the third port a and used for supplementing oil to the movable arm rod cavity and/or the movable arm rod-free cavity. The floating adjustment of the movable arm cylinder is realized, and meanwhile, the structure of the hydraulic oil circuit is simplified, so that the operation flow of operators is simplified when the horizontal pushing operation is executed.

Inventors

SUI PENGCHAO
DONG ZHIXIN
REN JIAN
XUE SHOUKANG
JI XIAOWEI
WANG FEI

Assignees

潍柴动力股份有限公司
潍柴液压传动有限公司

Dates

Publication Date: 20260505
Application Date: 20260316

Claims (10)

1. A hydraulic system for an excavator, comprising: An oil tank (1); the output end of the back pressure valve (2) is communicated with the oil tank (1); A first boom valve (3) comprising a first port a (31), a second port a (32) and a third port a (33), wherein the first port a (31) is used for being communicated with a boom rod cavity (120) of a boom cylinder (100), the second port a (32) is used for being communicated with a boom rod-free cavity (110) of the boom cylinder (100), the third port a (33) is communicated with an input end of the back pressure valve (2), and when a valve core of the first boom valve (3) is in a floating position, the first port a (31), the second port a (32) and the third port a (33) are mutually communicated; And the oil supplementing oil way is communicated with the third port a (33) and is used for supplementing oil to the movable arm rod cavity (120) and/or the movable arm rod-free cavity (110).
2. The hydraulic system for an excavator according to claim 1, wherein the oil make-up oil circuit comprises a first pump body (4), the input end of the first pump body (4) being in communication with the oil tank (1); the first movable arm valve (3) further comprises a fourth port a (34) and a fifth port a (35), the output end of the first pump body (4) is communicated with the fourth port a (34), and the fifth port a (35) is respectively communicated with the input end of the back pressure valve (2) and the third port a (33); When the spool of the first boom valve (3) is in the floating position, the fourth port a (34) communicates with the fifth port a (35).
3. The hydraulic system for an excavator according to claim 2, wherein the first boom valve (3) further comprises a sixth port a (36), the sixth port a (36) being in communication with the output of the first pump body (4) through a first one-way valve (5), the first one-way valve (5) allowing the one-way flow of the oil from the first pump body (4) to the sixth port a (36); When the spool of the first boom valve (3) is in the lifted position, the first port a (31) is communicated with the third port a (33), and the sixth port a (36) is communicated with the second port a (32).
4. The hydraulic system for an excavator of claim 2 further comprising: The input end of the second pump body (6) is communicated with the oil delivery end of the oil tank (1); A second boom valve (7) comprising a first port b (71), a second port b (72), a third port b (73), a fourth port b (74), a fifth port b (75) and a sixth port b (76), said first port b (71) being adapted to communicate with the boom rod chamber (120), said second port b (72) being adapted to communicate with the boom rod-less chamber (110), said third port b (73) being adapted to communicate with an input of the back pressure valve (2), said fourth port b (74) being adapted to communicate with an output of the second pump body (6), said fifth port b (75) being adapted to communicate with an input of the back pressure valve (2), said sixth port b (76) being adapted to communicate with an output of the second pump body (6) via a second one-way valve (8), said second one-way valve (8) allowing said oil to flow from said second pump body (6); When the spool of the second boom valve (7) is in the lifted position, the first port b (71) is communicated with the third port b (73), and the sixth port b (76) is communicated with the second port b (72); The fourth port b (74) communicates with the fifth port b (75) when the spool of the second boom valve (7) is in a floating position.
5. The hydraulic system for an excavator according to claim 4, wherein the second port a (32) communicates with the third port a (33) and the fourth port a (34) communicates with the fifth port a (35) when the spool of the first boom valve (3) is in the lowered position; when the spool of the second boom valve (7) is in the lowered position, the second port b (72) communicates with the third port b (73), and the sixth port b (76) communicates with the first port b (71).
6. The hydraulic system for an excavator of any one of claims 1-5 further comprising: The input end of the second pump body (6) is communicated with the oil delivery end of the oil tank (1); A boom valve (9), the boom valve (9) comprising a first port c (91), a second port c (92), a third port c (93) and a sixth port c (96), the first port c (91) being configured to communicate with a boom cavity (320) of a boom cylinder (300), the second port c (92) being configured to communicate with a boom-less cavity (310) of the boom cylinder (300), the third port c (93) being configured to communicate with an input of the back pressure valve (2) and with the third port a (33), respectively, the sixth port c (96) being configured to communicate with an output of the second pump body (6) via a third one-way valve (10), the third one-way valve (10) allowing one-way communication of the oil from the second pump body (6) to the sixth port c (96); when the valve core of the bucket rod valve (9) is in a forward extending position, the sixth port c (96) is communicated with the second port c (92), and the first port c (91) is communicated with the third port c (93); When the spool of the arm valve (9) is in the retracted position, the sixth port c (96) communicates with the first port c (91), and the second port c (92) communicates with the third port c (93).
7. The hydraulic system for an excavator according to claim 6, wherein the stick valve (9) further comprises a fourth port c (94) and a fifth port c (95), the fourth port c (94) being in communication with the output of the second pump body (6), the fifth port c (95) being in communication with the input of the back pressure valve (2) and the third port a (33); when the spool of the arm valve (9) is in the locking position, the fourth port c (94) is communicated with the fifth port c (95).
8. A valve structure adapted for use in the hydraulic system for an excavator of any one of claims 1 to 7, the valve structure comprising: The valve island (11) is sequentially provided with a first oil return path (111), a rodless cavity oil path (112), a rod cavity oil path (113) and a second oil return path (114) along a first direction (X), wherein the first oil return path (111) and the second oil return path (114) are respectively communicated with the oil return end of the oil tank (1), the rodless cavity oil path (112) is used for being communicated with the movable arm rodless cavity (110), the rod cavity oil path (113) is used for being communicated with the movable arm rod cavity (120), the valve island (11) is also provided with a first mounting cavity, and the first mounting cavity is communicated with the first oil return path (111), the rodless cavity oil path (112), the rod cavity oil path (113) and the second oil return path (114) along the first direction (X). The first valve core (12) is inserted into the first mounting cavity and can move along the first direction (X) relative to the valve island (11), and the first valve core (12) is provided with a first guide oil path (121) and a second guide oil path (122) along the first direction (X); When the first valve core (12) is at the floating position, the first guide oil path (121) is communicated with the first oil return path (111) and the rodless cavity oil path (112), and the second guide oil path (122) is communicated with the rod cavity oil path (113) and the second oil return path (114).
9. A construction machine comprising the hydraulic system for an excavator according to any one of claims 1 to 7, or the valve structure according to claim 8.
10. The construction machine according to claim 9, further comprising a bucket (600), a bucket cylinder (500), an arm (400), an arm cylinder (300), a boom (200), and a boom cylinder (100), wherein the body 700, the boom (200), the arm (400), and the bucket (600) are sequentially hinged end to end, the telescopic ends of the boom cylinder (100) are respectively hinged to the body 700 and the boom (200), the telescopic ends of the arm cylinder (300) are respectively hinged to the boom (200) and the arm (400), and the telescopic ends of the bucket cylinder (500) are respectively hinged to the boom (200) and the bucket (600), so as to complete rotation of the bucket (600) relative to the arm (400).

Description

Hydraulic system for excavator, valve structure and engineering machinery Technical Field The invention relates to the technical field of engineering machinery, in particular to a hydraulic system for an excavator, a valve structure and engineering machinery. Background In the field of engineering machinery, in particular to earth machinery operations such as excavators, loaders and the like, horizontal pushing operation is a common working condition, and loose materials (such as sand, soil and the like) need to be pushed and leveled along the ground by using a working device. The conventional flat pushing action relies on the driver to manually coordinate and control three sets of work devices, namely, a bucket, a boom and an arm, so that the three sets of work devices keep synchronous movement in the horizontal direction. However, in the actual operation process, because of the difference between the movement track and the hydraulic driving characteristics of each working device, the driver must adjust the extension and the retraction of each device in real time by respectively manipulating a plurality of operation handles, so as to maintain the fit and horizontal pushing between the bottom of the bucket and the ground. The control mode has extremely high requirements on experience and operation proficiency of a driver, is high in coordination difficulty, and is extremely easy to cause poor flatness, low efficiency and the like due to the fact that the bucket is gnawed or lifted off the ground due to asynchronous coordination. Accordingly, there is a need for a hydraulic system for an excavator, a valve structure, and a construction machine to solve the above problems. Disclosure of Invention The invention aims to provide a hydraulic system, a valve structure and engineering machinery for an excavator, which are used for solving the problem that a driver is required to coordinate a bucket rod, a bucket and a movable arm multi-rod when the conventional excavator performs a horizontal pushing operation. In one aspect, the present invention provides a hydraulic system for an excavator, the hydraulic system for an excavator including: An oil tank; The output end of the back pressure valve is communicated with the oil tank; A first boom valve including a first port a for communicating with a boom rod chamber of a boom cylinder, a second port a for communicating with a boom rod-less chamber of the boom cylinder, and a third port a for communicating with an input end of the back pressure valve, the first port a, the second port a, and the third port a being communicated with each other when a spool of the first boom valve is in a floating position; and the oil supplementing oil way is communicated with the third port a and is used for supplementing oil to the movable arm rod cavity and/or the movable arm rod-free cavity. As a preferable mode of the hydraulic system for an excavator, the oil supply passage includes a first pump body, and an input end of the first pump body is communicated with the oil tank; the first movable arm valve further comprises a fourth port a and a fifth port a, wherein the output end of the first pump body is communicated with the fourth port a, and the fifth port a is respectively communicated with the input end of the back pressure valve and the third port a; when the spool of the first boom valve is at the floating position, the fourth port a communicates with the fifth port a. As a preferable mode of the hydraulic system for an excavator, the first boom valve further includes a sixth port a, the sixth port a communicates with the output end of the first pump body through a first check valve, and the first check valve allows the oil to flow in one direction from the first pump body to the sixth port a; When the spool of the first boom valve is in the raised position, the first port a communicates with the third port a, and the sixth port a communicates with the second port a. As a preferable mode of the hydraulic system for an excavator, the hydraulic system further includes: the input end of the second pump body is communicated with the oil delivery end of the oil tank; A second boom valve including a first port b for communicating with a boom chamber of the boom cylinder, a second port b for communicating with a boom-no-rod chamber of the boom cylinder, a third port b for communicating with an input of the back pressure valve, a fourth port b for communicating with an output of the second pump body, a fifth port b for communicating with an input of the back pressure valve, and a sixth port b for communicating with an output of the second pump body through a second check valve that allows the oil to flow from the second pump body; when the spool of the second boom valve is in the lifted position, the first port b communicates with the third port b, and the sixth port b communicates with the second port b; When the spool of the second boom valve is in the floating position, the fourt