CN219452551U - Multi-cylinder hydraulic system and crane - Google Patents

Abstract

The utility model provides a multi-cylinder hydraulic system and a crane, and relates to the technical field of engineering machinery. In the hydraulic system, two cylinders with different operation functions can share one hydraulic pump and one oil tank, so that the installation efficiency is high, and the cost and the space occupation are also saved.

Description

Multi-cylinder hydraulic system and crane

Technical Field

The utility model relates to the technical field of engineering machinery, in particular to a multi-cylinder hydraulic system and a crane.

Background

The climbing frame of the tower crane normally realizes lifting movement under the action of a hydraulic system, the climbing frame usually comprises an inner frame and an outer frame which are sleeved with each other, two types of oil cylinders in the hydraulic system are usually a main oil cylinder and an auxiliary oil cylinder respectively, the main oil cylinder is used for driving the inner frame and the outer frame to move relatively so as to realize lifting of the climbing frame, and the auxiliary oil cylinder can be used for driving a bolt to horizontally insert into the outer frame and the inner frame so as to realize fixing of the height of the climbing frame.

However, in the existing multi-cylinder hydraulic system, the main hydraulic station is usually used for telescoping a single cylinder, that is, the main cylinder is independently driven by one hydraulic station (including a hydraulic pump, a motor for driving the hydraulic pump, an oil tank, and the like), and the auxiliary cylinder is independently driven by another hydraulic station, and the hydraulic station is used for telescoping a single cylinder, so that the hydraulic station is various, the installation efficiency is affected, and the arrangement of a plurality of hydraulic stations also occupies a large construction area and has high cost.

Disclosure of Invention

The present utility model aims to solve at least one of the above technical problems.

In order to solve the problems, the utility model provides a multi-cylinder hydraulic system, which comprises an oil tank, a hydraulic pump, a first reversing valve, a second reversing valve, a main cylinder and an auxiliary cylinder, wherein an oil inlet of the hydraulic pump is communicated with the oil tank, an oil inlet of the first reversing valve is communicated with an oil outlet of the hydraulic pump, an oil return port of the first reversing valve is communicated with an oil inlet of the second reversing valve, a first working port of the first reversing valve is communicated with a rodless cavity of the main cylinder, a second working port of the first reversing valve is communicated with a rod cavity of the main cylinder, an oil return port of the second reversing valve is communicated with the oil tank, a first working port of the second reversing valve is communicated with a rod cavity of the auxiliary cylinder, and when the first reversing valve is configured to be in a neutral position, the first reversing valve is in a normally open state with the oil return port, and when the second reversing valve is configured to be in a neutral position, the second reversing valve is in a normally open state with the oil inlet and the oil return port.

Compared with the prior art, the multi-cylinder hydraulic system provided by the utility model has the following beneficial effects:

because the oil inlet and the oil return port are in a normally open state when the first reversing valve is configured to be in the middle position, and the oil inlet and the oil return port are in a normally open state when the second reversing valve is configured to be in the middle position. Thus, when the first reversing valve is in a working position (non-middle position), and the second reversing valve is in the middle position, oil output by an oil outlet of the hydraulic pump can enter a rodless cavity of the main oil cylinder from the first reversing valve, and then the oil in the rod cavity of the main oil cylinder sequentially passes through an oil inlet and an oil return port which are normally opened in the middle position of the first reversing valve and the second reversing valve and returns to the oil tank, so that the telescopic work of the main oil cylinder is realized; when the main oil cylinder stretches out and draws back to the place, can switch the first switching-over valve to the meso position again, and switch the second switching-over valve to the operational position (non-meso position), so after the oil of the oil-out output of hydraulic pump passes through the oil inlet and the oil return opening of first switching-over valve in proper order, again through the operational position of second switching-over valve like the rodless chamber of entering auxiliary oil cylinder, the oil in the rodless chamber of auxiliary oil cylinder returns to the oil tank after the operational position of second switching-over valve again, and then realize the flexible of auxiliary oil cylinder, in whole hydraulic system, the different hydro-cylinders of two kinds of operation functions (main oil cylinder and auxiliary oil cylinder) can share a hydraulic pump and oil tank, that is, the different hydro-cylinder of two kinds of operation functions and a hydraulic station are integrated in a hydraulic system, installation effectiveness is high, cost and space occupancy have also been saved.

Further, the multi-cylinder hydraulic system further comprises a first oil way and a second oil way, wherein an oil return port of the first reversing valve is communicated with an oil inlet of the second reversing valve through the first oil way, a first end of the second oil way is communicated with an oil outlet of the hydraulic pump, a second end of the second oil way is communicated with the oil tank, the second oil way comprises a first node and a second node which are positioned between the first end and the second end, the first node is positioned between the second node and the first end of the second oil way, an oil inlet of the first reversing valve is communicated with the second oil way at the first node, an oil return port of the second reversing valve is communicated with the second oil way at the second node, and a first overflow valve is arranged at a position between the second end of the second oil way and the second node.

Further, the multi-cylinder hydraulic system further comprises a plurality of third oil ways and a fourth oil way, the main oil cylinder is provided with a plurality of third oil ways, one ends of the third oil ways are simultaneously communicated with the first working interfaces of the first reversing valves, the other ends of the third oil ways are respectively communicated with corresponding rodless cavities of the main oil cylinder, one ends of the fourth oil ways are respectively communicated with the second working interfaces of the first reversing valves, the other ends of the fourth oil ways are respectively communicated with rod cavities of the main oil cylinder, each third oil way is provided with a one-way throttle valve serial assembly, each one-way throttle valve serial assembly comprises two second one-way throttle valves which are serially connected, and the flow limiting directions of the one-way valves in the two second one-way throttle valves are opposite.

Further, a main balance valve is arranged on the third oil way, the main balance valve is positioned between the unidirectional throttle valve serial assembly and the main oil cylinder, and a control strand of the main balance valve is communicated with a rod cavity of the main oil cylinder.

Further, the multi-cylinder hydraulic system further comprises a plurality of sixth oil paths, one ends of the sixth oil paths are respectively communicated with the corresponding third oil paths and are close to the rodless cavity of the main cylinder, the other ends of the sixth oil paths are respectively communicated with the oil tank, and a second overflow valve is arranged on the sixth oil paths.

Further, the multi-cylinder hydraulic system further comprises a fifth oil way and a ninth oil way, one end of the fifth oil way is communicated with the second oil way, the other end of the fifth oil way is respectively communicated with the rod cavity of the main cylinder, a first throttle valve and a first stop valve are respectively arranged on the fifth oil way, one end of the ninth oil way is communicated with the second oil way, the other end of the ninth oil way is communicated with the oil tank, and a second stop valve is arranged on the ninth oil way.

Further, pressure sensors are respectively arranged on the third oil paths or the sixth oil paths, and the pressure sensors are used for detecting the rodless cavity pressure corresponding to the main oil cylinder.

Further, the multi-cylinder hydraulic system further comprises a seventh oil way and an eighth oil way, the first working interface of the second reversing valve is communicated with the rodless cavity of the auxiliary oil cylinder through the seventh oil way, the second working interface of the second reversing valve is communicated with the rod cavity of the auxiliary oil cylinder through the eighth oil way, and the seventh oil way and the eighth oil way are respectively provided with a pressure reducing valve.

Further, the seventh oil passage and the eighth oil passage are respectively provided with a first one-way throttle valve; and/or an auxiliary balance valve is arranged at the position, close to the auxiliary oil cylinder, on the seventh oil way, and a control strand of the auxiliary balance valve is communicated with a rod cavity of the auxiliary oil cylinder.

The utility model also provides a crane comprising the multi-cylinder hydraulic system.

Because the technical improvement and beneficial effects of the crane are the same as those of the multi-cylinder hydraulic system, the crane is not repeated.

Drawings

Fig. 1 is a hydraulic schematic diagram of a multi-cylinder hydraulic system according to an embodiment of the present utility model.

Reference numerals illustrate:

11. a first oil passage; 12. a second oil path; 121. a first overflow valve; 13. a third oil passage; 131. a one-way throttle valve series assembly; 132. a main balance valve; 14. a fourth oil passage; 15. a fifth oil passage; 151. a first throttle valve; 152. a first stop valve; 16. a sixth oil passage; 161. a second overflow valve; 17. a seventh oil passage; 171. a pressure reducing valve; 172. a first one-way throttle valve; 173. a secondary balance valve; 18. an eighth oil passage; 19. a ninth oil passage; 191. a second shut-off valve; 21. a first reversing valve; 22. a second reversing valve; 23. an oil tank; 24. a hydraulic pump; 25. a master cylinder; 251. a pressure sensor; 26. an auxiliary oil cylinder; 31. an oil inlet filter; 32. a cooler; 33. and (5) an oil return filter.

Detailed Description

In order that the above objects, features and advantages of the utility model will be readily understood, a more particular description of the utility model will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.

In the description of the present utility model, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of description and simplification of the description, and do not indicate or imply that the apparatus or element in question must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

Moreover, in the drawings, the X-axis represents the lateral direction, i.e., the left-right position, and the positive direction of the X-axis (i.e., the arrow of the X-axis is directed) represents the left, and the negative direction of the X-axis (i.e., the direction opposite to the positive direction of the X-axis) represents the right; the Z-axis in the drawing represents vertical, i.e., up-down position, and the positive direction of the Z-axis (i.e., the arrow pointing in the Z-axis) represents up and down, and the negative direction of the Z-axis (i.e., the direction opposite to the positive direction of the Z-axis).

It should also be noted that the foregoing X-axis and Z-axis are meant to be illustrative of the present utility model and to simplify the description, and are not intended to indicate or imply that the devices or elements referred to must be in a particular orientation, be constructed and operated in a particular orientation, and are not to be construed as limiting the utility model.

Referring to fig. 1, a multi-cylinder hydraulic system according to the embodiment of the utility model includes an oil tank 23, a hydraulic pump 24, a first reversing valve 21, a second reversing valve 22, a master cylinder 25 and a slave cylinder 26, wherein an oil inlet of the hydraulic pump 24 is communicated with the oil tank 23, an oil inlet (P port) of the first reversing valve 21 is communicated with an oil outlet of the hydraulic pump 24, an oil return port (T port) of the first reversing valve 21 is communicated with an oil inlet (P port) of the second reversing valve 22, a first working port (a port) of the first reversing valve 21 is communicated with a rodless cavity of the master cylinder 25, a second working port (B port) of the first reversing valve 21 is communicated with a rod cavity of the master cylinder 25, an oil return port (T port) of the second reversing valve 22 is communicated with the oil tank 23, a first working port (a port) of the second reversing valve 22 is communicated with a rod cavity of the slave cylinder 26, when the first reversing valve 21 is configured to be in a neutral position, the first reversing valve 21 is configured to be in a state of the oil return port and the second reversing valve 22 is configured to be in a normally open position when the second reversing valve 22 is in a normally open state.

Wherein, the oil return port of the first reversing valve 21 and the oil inlet port of the second reversing valve 22 can be communicated through the first oil path 11.

In this embodiment, since the oil inlet and the oil return port are normally open when the first reversing valve 21 is configured to be in the neutral position, the oil inlet and the oil return port are normally open when the second reversing valve 22 is configured to be in the neutral position. Therefore, when the first reversing valve 21 is in the working position (non-neutral position), and the second reversing valve 22 is in the neutral position, the oil output from the oil outlet of the hydraulic pump 24 can enter the rodless cavity of the main cylinder 25 from the first reversing valve 21, and then the oil in the rod cavity of the main cylinder 25 sequentially passes through the normally open oil inlet and oil return port of the first reversing valve 21, the first oil path 11 and the second reversing valve 22, and returns to the oil tank 23, thereby realizing the telescopic operation of the main cylinder 25.

When the main oil cylinder 25 stretches out and draws back to the right, can switch over the first reversing valve 21 to the middle position again, and switch over the second reversing valve 22 to the working position (not middle position), so, after the oil that the oil outlet of the hydraulic pump 24 exports passes through the oil inlet and the oil return port of the first reversing valve 21 in turn, pass through the working position of the second reversing valve 22 and enter the rodless cavity of the auxiliary oil cylinder 26 for example, the oil in the rod cavity of the auxiliary oil cylinder 26 returns to the oil tank 23 after passing through the working position of the second reversing valve 22 again, and then realize the stretching out and drawing back of the auxiliary oil cylinder 26, in the whole hydraulic system, the oil cylinders (main oil cylinder 25 and auxiliary oil cylinder 26) with two different operation functions can share one hydraulic pump 24 and oil tank 23, namely, the oil cylinders with two different operation functions and one hydraulic station are integrated in one hydraulic system, the installation efficiency is high, and the cost and space occupation rate are saved.

In addition, in the multi-cylinder hydraulic system, when two cylinders with different operation functions are connected with the hydraulic pump 24, only two reversing valves, namely the first reversing valve 21 and the second reversing valve 22, are needed to supply for the main cylinder 25 and the auxiliary cylinder 26 respectively, and complex multi-way valves are not needed to be purchased or designed, so that the cost and the space occupation rate of the hydraulic system are further reduced, and the installation efficiency is further improved.

Specifically, the first reversing valve 21 and the second reversing valve 22 may be three-position four-way reversing valves, which have a middle position and two working positions, as shown in fig. 1, when the first reversing valve 21 is at a right position and the second reversing valve 22 is at the middle position, oil output by an oil outlet of the hydraulic pump 24 sequentially passes through an oil inlet of the first reversing valve 21 and a first working interface and then enters a rodless cavity of the main cylinder 25, and oil in the rod cavity of the main cylinder 25 sequentially passes through a second working interface of the first reversing valve 21, an oil return port, the first oil path 11, an oil inlet of the second reversing valve 22 and an oil return port and then returns to the oil tank 23, so as to realize extension of the main cylinder 25.

When the first reversing valve 21 is at the left position and the second reversing valve 22 is at the middle position, the oil output by the oil outlet of the hydraulic pump 24 sequentially passes through the oil inlet of the first reversing valve 21 and the second working interface and then enters the rod cavity of the main oil cylinder 25, and the oil in the rod-free cavity of the main oil cylinder 25 sequentially passes through the first working interface, the oil return port, the first oil way 11 and the oil inlet and the oil return port of the second reversing valve 22 of the first reversing valve 21 and then returns to the oil tank 23, so that the shrinkage of the main oil cylinder 25 is realized.

When the first reversing valve 21 is in the middle position and the second reversing valve 22 is in the right position, the oil output by the oil outlet of the hydraulic pump 24 sequentially passes through the oil inlet, the oil return port, the first oil path 11, the oil inlet of the second reversing valve 22 and the first working port of the first reversing valve and then enters the rodless cavity of the auxiliary oil cylinder 26, and the oil in the rod cavity of the auxiliary oil cylinder 26 sequentially passes through the second working port and the oil return port of the second reversing valve 22 and then returns to the oil tank 23, so that the extension of the auxiliary oil cylinder 26 is realized.

When the first reversing valve 21 is in the middle position and the second reversing valve 22 is in the left position, the oil output by the oil outlet of the hydraulic pump 24 sequentially passes through the oil inlet, the oil return port, the first oil path 11, the oil inlet of the second reversing valve 22 and the second working port of the first reversing valve 21 and then enters the rod cavity of the auxiliary oil cylinder 26, and the oil in the rodless cavity of the auxiliary oil cylinder 26 sequentially passes through the first working port and the oil return port of the second reversing valve 22 and then returns to the oil tank 23, so that the shrinkage of the auxiliary oil cylinder 26 is realized.

Referring to fig. 1, optionally, the multi-cylinder hydraulic system further includes a second oil path 12, a first end of the second oil path 12 communicates with an oil outlet of the hydraulic pump 24, a second end of the second oil path 12 communicates with the oil tank 23, the second oil path 12 includes a first node and a second node between the first end and the second end, the first node is located between the second node and the first end of the second oil path 12, an oil inlet of the first reversing valve 21 communicates with the second oil path 12 at the first node, an oil return port of the second reversing valve 22 communicates with the second oil path 12 at the second node, and a first relief valve 121 is provided at a position between the second end of the second oil path 12 and the second node.

In this embodiment, when the main cylinder 25 and the auxiliary cylinder 26 do not need to perform telescopic movement, the first reversing valve 21 and the second reversing valve 22 are both at the stations, and at this time, the oil output from the oil outlet of the hydraulic pump 24 can sequentially return to the oil tank 23 from the oil inlet of the first reversing valve 21, the oil return port, the oil inlet of the first oil path 11, and the oil inlet and the oil return port of the second reversing valve 22, thereby achieving unloading of the oil pump. If the first oil way 11 is blocked, the overflow of the first overflow valve 121 on the second oil way 12 can be used to avoid the pressure holding of the oil way and the consistent heating of the hydraulic oil, so as to realize the oil way protection.

Referring to fig. 1, optionally, the multi-cylinder hydraulic system further includes a plurality of third oil paths 13 and a fourth oil path 14, where the master cylinder 25 is provided with a plurality of third oil paths 13, one end of each of the third oil paths 13 is simultaneously communicated with the first working ports of the first reversing valves 21, the other ends of the third oil paths 13 are respectively communicated with the rodless cavities of the corresponding master cylinders 25, one end of the fourth oil path 14 is communicated with the second working ports of the first reversing valves 21, the other ends of the fourth oil paths 14 are respectively communicated with the rod cavities of the plurality of master cylinders 25, and each of the third oil paths 13 is provided with a unidirectional throttle valve serial assembly 131.

In this embodiment, in the tower crane, the number of master cylinders 25 is generally plural, and the plurality of master cylinders 25 collectively realize the lifting of the climbing frame. On the basis, through arranging the unidirectional throttle valve serial components 131 on the third oil ways 13 respectively, the flow of the rodless cavities of the main oil cylinders 25 in and out of oil can be ensured to be consistent or kept within an allowable difference range, and the synchronism of the main oil cylinders 25 is further ensured.

Specifically, the unidirectional throttle valve serial assembly 131 includes two second unidirectional throttle valves connected in series on the third oil path 13, and on the same third oil path 13, the flow limiting directions of the unidirectional valves in the two second unidirectional throttle valves are opposite.

Referring to fig. 1, optionally, a main balance valve 132 is disposed on the third oil path 13, the main balance valve 132 is located between the unidirectional throttle valve series assembly 131 and the main cylinder 25, and a control strand of the main balance valve 132 is in communication with a rod chamber of the main cylinder 25.

In this embodiment, by providing the main balance valve 132, it is possible to ensure that the main cylinder 25 is not unstable due to the change of the external load when it is extended or contracted.

Referring to fig. 1, optionally, the multi-cylinder hydraulic system further includes a plurality of sixth oil passages 16, one ends of the plurality of sixth oil passages 16 are respectively communicated with the corresponding third oil passages 13 and are close to the rodless cavity of the master cylinder 25, the other ends of the plurality of sixth oil passages 16 are respectively communicated with the oil tank 23, and a second relief valve 161 is provided on the sixth oil passages 16.

In this embodiment, when the master cylinder 25 needs to be contracted, the first reversing valve 21 is at the right position, the oil output by the hydraulic pump 24 passes through the oil inlet of the first reversing valve 21, the second working port and the fourth oil path 14 and then enters the rod cavity of the master cylinder 25, if the unidirectional throttle valve serial assembly 131 or the master balance valve 132 fails, the oil in the rodless cavity of the master cylinder 25 cannot return to the oil tank 23 from the unidirectional throttle valve serial assembly 131 and the master balance valve 132, at this time, the oil in the rodless cavity of the master cylinder 25 can also return to the oil tank 23 from the second overflow valve 161 on the sixth oil path 16, the emergency unloading of the rodless cavity of the master cylinder 25 ensures that the master cylinder 25 can be contracted stably, so that the climbing frame descends stably.

Referring to fig. 1, optionally, the multi-cylinder hydraulic system further includes a fifth oil path 15 and a ninth oil path 19, one end of the fifth oil path 15 is communicated with the second oil path 12, the other end of the fifth oil path 15 is respectively communicated with rod cavities of the plurality of master cylinders 25, a first throttle 151 and a first stop valve 152 are respectively disposed on the fifth oil path 15, one end of the ninth oil path 19 is communicated with the second oil path 12, the other end of the ninth oil path 19 is communicated with the oil tank 23, and a second stop valve 191 is disposed on the ninth oil path 19.

In this embodiment, when the master cylinder 25 needs to be contracted, if the first reversing valve 21 fails, the first stop valve 152 may be opened, the oil output by the hydraulic pump 24 may enter the rod cavity of the master cylinder 25 through the first throttle valve 151 on the fifth oil path 15, and the oil in the rod-free cavity of the master cylinder 25 may overflow from the second overflow valve 161 on the sixth oil path 16 and return to the oil tank 23, so as to complete emergency unloading of the rod-free cavity of the master cylinder 25.

In this embodiment, when the main cylinder 25 needs to be contracted, if the hydraulic pump 24 fails, but the main balance valve 132, the unidirectional throttle valve serial assembly 131 and the first reversing valve 21 do not fail, at this time, the first stop valve 152 may be removed and a manual pump may be installed, while the second stop valve 191 is opened, then, the oil in the oil tank 23 may sequentially enter the rod cavity of the main cylinder 25 through the ninth oil path 19 and the fifth oil path 15 by the manual pump, and the oil in the rodless cavity of the main cylinder 25 may return to the oil tank 23 through the balance valve, the unidirectional throttle valve serial assembly 131 and the first reversing valve 21, so as to complete the emergency unloading of the rodless cavity of the main cylinder 25.

In this embodiment, if the hydraulic pump 24 fails and at least one of the main balance valve 132, the one-way throttle valve serial assembly 131 and the first reversing valve 21 fails, at this time, the first stop valve 152 may be removed and a manual pump may be installed, while the second stop valve 191 may be opened, then, the oil in the oil tank 23 may sequentially pass through the ninth oil path 19 and the fifth oil path 15 and then enter the rod cavity of the main oil tank 25 by the manual pump, and the oil in the rodless cavity of the main oil tank 25 may overflow through the second overflow valve 161 on the sixth oil path 16 and then return to the oil tank 23, and also the emergency unloading of the rodless cavity of the main oil tank 25 may be completed.

Referring to fig. 1, optionally, a pressure sensor 251 is disposed on each of the third oil passages 13 or the sixth oil passages 16, and the pressure sensor 251 is configured to detect a rodless cavity pressure corresponding to the master cylinder 25.

In this embodiment, the pressure sensor 251 detects the pressure of the rodless cavity corresponding to the master cylinder 25, so that the pressure difference of the oil pressure when the rodless cavity of the master cylinder 25 is fed can be monitored to be in a reasonable range, if the pressure difference is unreasonable, the pressure difference can be in a reasonable range by corresponding means, such as performing interception adjustment through the unidirectional throttle valve serial assembly 131, so that the synchronism of the master cylinders 25 is ensured.

Referring to fig. 1, the multi-cylinder hydraulic system may further include a seventh oil path 17 and an eighth oil path 18, the first working port of the second directional valve 22 is communicated with the rodless chamber of the slave cylinder 26 through the seventh oil path 17, the second working port of the second directional valve 22 is communicated with the rod-containing chamber of the slave cylinder 26 through the eighth oil path 18, and the seventh oil path 17 and the eighth oil path 18 are respectively provided with a pressure reducing valve 171.

In this embodiment, when the first reversing valve 21 is in the middle position and the second reversing valve 22 is in the right position, the oil output by the hydraulic pump 24 enters the seventh oil path 17 through the second reversing valve 22, is depressurized by the depressurization valve 171, and then enters the rodless cavity of the auxiliary oil cylinder 26, so as to meet the oil pressure requirement of the auxiliary oil cylinder 26.

When the first reversing valve 21 is in the middle position and the second reversing valve 22 is in the left position, the oil output by the hydraulic pump 24 enters the eighth oil path 18 through the second reversing valve 22, and also enters the rodless cavity of the auxiliary oil cylinder 26 after being depressurized through the depressurization valve 171, so as to meet the oil pressure requirement of the auxiliary oil cylinder 26.

Referring to fig. 1, the seventh oil passage 17 and the eighth oil passage 18 are optionally provided with first one-way throttle valves 172, respectively; and/or a secondary balance valve 173 is arranged on the seventh oil path 17 at a position close to the secondary oil cylinder 26, and a control strand of the secondary balance valve 173 is communicated with a rod cavity of the secondary oil cylinder 26.

In this embodiment, by providing a first one-way throttle valve 172 on each of the seventh oil path 17 and the eighth oil path 18, the first one-way throttle valve 172 is used to adjust the flow rate of hydraulic oil in the direction from the auxiliary oil cylinder 26 to the second reversing valve 22, so that the flow rate of oil entering and exiting the auxiliary oil cylinder 26 can be adjusted to meet the flow rate requirement. By providing the auxiliary balance valve 173 on the seventh oil passage 17, the auxiliary balance valve 173 is used for balancing the pressure of the rodless cavity oil port and the rod cavity oil port of the auxiliary oil cylinder 26, so as to ensure that the auxiliary oil cylinder 26 is not unstable due to the change of external load when extending and contracting.

Referring to fig. 1, optionally, an oil inlet filter 31 is disposed between an oil inlet of the hydraulic pump 24 and the oil tank 23, and a cooler 32 and an oil return filter 33 are sequentially disposed between the second oil path 12 and the oil tank 23. The oil return filter 33 may be an oil return filter 33 with an indication of oil contamination. The cooler 32 may be connected in parallel with a third one-way shut-off valve, and the cooler 32 may be shut off when oil is not required to be returned, and oil may then be returned from the third one-way shut-off valve to the tank 23.

Another embodiment of the utility model also provides a crane comprising a multi-cylinder hydraulic system as previously described.

Because the technical improvement and beneficial effects of the crane are the same as those of the multi-cylinder hydraulic system, the crane is not repeated.

The terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" and "a second" may explicitly or implicitly include at least one such feature.

Although the present disclosure is disclosed above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the scope of the disclosure.

Claims (10)

1. The multi-cylinder hydraulic system is characterized by comprising an oil tank (23), a hydraulic pump (24), a first reversing valve (21), a second reversing valve (22), a main cylinder (25) and an auxiliary cylinder (26), wherein an oil inlet of the hydraulic pump (24) is communicated with the oil tank (23), an oil inlet of the first reversing valve (21) is communicated with an oil outlet of the hydraulic pump (24), an oil return port of the first reversing valve (21) is communicated with an oil inlet of the second reversing valve (22), a first working interface of the first reversing valve (21) is communicated with a rodless cavity of the main cylinder (25), a second working interface of the first reversing valve (21) is communicated with a rod-like cavity of the main cylinder (25), an oil return port of the second reversing valve (22) is communicated with the oil tank (23), a first working interface of the second reversing valve (22) is communicated with a rodless cavity of the auxiliary cylinder (26), and a second working interface of the second reversing valve (22) is communicated with a rod-like cavity of the auxiliary cylinder (26);

when the first reversing valve (21) is arranged in the middle position, an oil inlet and an oil return port of the first reversing valve (21) are in a normally open state, and when the second reversing valve (22) is arranged in the middle position, an oil inlet and an oil return port of the second reversing valve (22) are in a normally open state.

2. The multiple-cylinder hydraulic system according to claim 1, further comprising a first oil passage (11) and a second oil passage (12), wherein an oil return port of the first reversing valve (21) communicates with an oil inlet of the second reversing valve (22) through the first oil passage (11), a first end of the second oil passage (12) communicates with an oil outlet of the hydraulic pump (24), a second end of the second oil passage (12) communicates with the oil tank (23), the second oil passage (12) includes a first node and a second node between the first end and the second end, and the first node is located between the second node and the first end of the second oil passage (12), an oil inlet port of the first reversing valve (21) communicates with the second oil passage (12) at the first node, an oil return port of the second reversing valve (22) communicates with the second oil passage (12) at the second node, and an overflow valve (121) is provided at a position between the second end of the second oil passage (12) and the second node.

3. The multi-cylinder hydraulic system according to claim 2, further comprising a plurality of third oil passages (13) and a fourth oil passage (14), wherein the master cylinder (25) is provided with a plurality of third oil passages (13), one end of each third oil passage (13) is simultaneously communicated with the first working port of the first reversing valve (21), the other ends of the third oil passages (13) are respectively communicated with the corresponding rodless cavities of the master cylinder (25), one end of the fourth oil passage (14) is communicated with the second working port of the first reversing valve (21), the other end of the fourth oil passage (14) is respectively communicated with the rod cavities of the plurality of master cylinders (25), each third oil passage (13) is provided with a one-way throttle serial assembly (131), the one-way throttle serial assembly (131) comprises two second one-way throttles which are serially connected, and the flow limiting directions of the one-way valves in the two second one-way throttles are opposite.

4. A multi-cylinder hydraulic system according to claim 3, characterized in that a main balance valve (132) is provided on the third oil circuit (13), the main balance valve (132) is located between the one-way throttle valve series assembly (131) and the main cylinder (25), and a control strand of the main balance valve (132) communicates with a rod chamber of the main cylinder (25).

5. A multi-cylinder hydraulic system according to claim 3 or 4, further comprising a plurality of sixth oil passages (16), wherein one ends of the sixth oil passages (16) are respectively communicated with the corresponding third oil passages (13) and are close to a rodless cavity of the master cylinder (25), the other ends of the sixth oil passages (16) are respectively communicated with the oil tank (23), and a second relief valve (161) is provided on the sixth oil passages (16).

6. The multi-cylinder hydraulic system according to claim 5, further comprising a fifth oil passage (15) and a ninth oil passage (19), wherein one end of the fifth oil passage (15) is communicated with the second oil passage (12), the other end of the fifth oil passage (15) is respectively communicated with the rod chamber of the master cylinder (25), a first throttle valve (151) and a first stop valve (152) are respectively provided on the fifth oil passage (15), one end of the ninth oil passage (19) is communicated with the second oil passage (12), the other end of the ninth oil passage (19) is communicated with the oil tank (23), and a second stop valve (191) is provided on the ninth oil passage (19).

7. The multi-cylinder hydraulic system according to claim 5, wherein a plurality of the third oil passages (13) or a plurality of the sixth oil passages (16) are respectively provided with a pressure sensor (251), and the pressure sensor (251) is configured to detect a rodless cavity pressure corresponding to the master cylinder (25).

8. The multi-cylinder hydraulic system according to claim 1, further comprising a seventh oil passage (17) and an eighth oil passage (18), wherein the first working port of the second reversing valve (22) communicates with the rodless chamber of the auxiliary cylinder (26) through the seventh oil passage (17), and the second working port of the second reversing valve (22) communicates with the rod-containing chamber of the auxiliary cylinder (26) through the eighth oil passage (18), and the seventh oil passage (17) and the eighth oil passage (18) are provided with pressure reducing valves (171), respectively.

9. The multiple-cylinder hydraulic system according to claim 8, characterized in that the seventh oil passage (17) and the eighth oil passage (18) are provided with a first one-way throttle valve (172), respectively; and/or a secondary balance valve (173) is arranged at a position, close to the secondary oil cylinder (26), on the seventh oil way (17), and a control strand of the secondary balance valve (173) is communicated with a rod cavity of the secondary oil cylinder (26).

10. Crane, characterized by comprising a multi-cylinder hydraulic system according to any of claims 1-9.