CN115898987A - Multi-working-condition safety pressure-adjustable forklift hydraulic system - Google Patents
Multi-working-condition safety pressure-adjustable forklift hydraulic system Download PDFInfo
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Abstract
The invention discloses a forklift hydraulic system with adjustable multi-working-condition safety pressure, which comprises an oil tank, an oil pump and a priority compensation valve, wherein an output port of the oil pump is connected with an inlet of the priority compensation valve, two outlets of the priority compensation valve are respectively connected with an inlet of a main switch valve and an inlet of an auxiliary switch valve, an outlet of the main switch valve is connected with a main oil way working port of the system, an oil way between the oil pump and the priority compensation valve is connected with the oil tank through a main overflow valve, an oil way between the auxiliary switch valve and an auxiliary oil way working port is connected with the oil tank through a proportional overflow valve, and overflow pressure parameters of the proportional overflow valve are adjusted according to the working conditions of the auxiliary oil way working port. The flow of each joint of the auxiliary oil way is stable, the speed is easy to control, the joint operation stability is improved, the hydraulic system is more integrated and compact, meanwhile, the overflow of each joint actuator of the valve blocks of the multiple actuators under the same high safety overflow parameter is avoided, and the unnecessary loss is reduced.
Description
Technical Field
The invention relates to the field of hydraulic systems, in particular to a forklift hydraulic system with adjustable multi-working-condition safety pressure.
Background
Fork truck equipment wide application in commodity circulation transportation field needs drive and control its equipment through hydraulic system. However, in the prior art, the hydraulic system of the forklift is simple in structure and few in functions, and in order to reduce cost, a single valve block with parallel or series-parallel oil passages of a plate valve or multiple execution structures is basically adopted. Therefore, the existing hydraulic system is difficult to realize the combined operation of all oil ways, and is difficult to meet the requirements of different forklift types and special working conditions. Meanwhile, for compact structure, the most of the circuits are connected to share one traditional mechanical safety overflow valve, the safety overflow valve can only set one safety overflow pressure parameter, under some working conditions, safety response is not timely enough, and great loss can be generated.
Therefore, how to provide a multi-working-condition safety pressure-adjustable forklift hydraulic system for providing adaptive safety overflow pressure for different working conditions is a technical problem which needs to be solved by technical personnel in the field at present.
Disclosure of Invention
The invention aims to provide a forklift hydraulic system with adjustable multi-working-condition safety pressure, which is provided with a main oil path and an auxiliary oil path, is provided with a proportional overflow valve, provides adaptive safety overflow pressure for different working conditions by adjusting the proportional overflow valve, improves the control accuracy, saves space and saves energy consumption.
In order to solve the technical problem, the invention provides a forklift hydraulic system with adjustable multi-operating-condition safety pressure, which comprises an oil tank, an oil pump and a priority compensation valve, wherein an output port of the oil pump is connected with an inlet of the priority compensation valve, two outlets of the priority compensation valve are respectively connected with an inlet of a main switching valve and an inlet of an auxiliary switching valve, an outlet of the main switching valve is connected with a main oil way working port of the system, the main oil way working port is connected with a main actuator, an outlet of the auxiliary switching valve is connected with an auxiliary oil way working port of the system, the auxiliary oil way working port is connected with an auxiliary actuator or a multi-actuator valve block, an oil way between the oil pump and the priority compensation valve is connected with the oil tank through a main overflow valve, an oil way between the auxiliary switching valve and the auxiliary oil way working port is connected with the oil tank through a proportional overflow valve, and overflow pressure parameters of the proportional overflow valve are adjusted and set according to the operating conditions of the auxiliary oil way working port.
Preferably, the priority compensation valve is a proportional control compensation valve, and is configured to control a flow rate output to the main switching valve and the auxiliary switching valve.
Preferably, the oil path between the auxiliary switch valve and the auxiliary oil path working port is further connected with the oil tank through a plurality of throttle valves connected in series, and the proportional overflow valve is connected with at least one throttle valve in parallel.
Preferably, the auxiliary switching valve is embodied as a proportional regulating valve.
Preferably, the priority compensation valve is provided with a monostable shunt passage connected with the main switching valve, and an oil passage between the priority compensation valve and the main switching valve is connected with the oil tank through an auxiliary switching valve.
Preferably, the main actuator is a main single-acting oil cylinder, the main oil path working port is further connected to the oil tank through a proportional flow compensation valve, when the main single-acting oil cylinder rises, the main switch valve is turned on, the proportional flow compensation valve is closed, the auxiliary switch valve is closed, when the main single-acting oil cylinder falls, the main switch valve is closed, the proportional flow compensation valve is turned on, and the auxiliary switch valve is turned on.
Preferably, an oil return switch valve is arranged at an outlet of the proportional flow compensation valve, when the proportional flow compensation valve is closed, the oil return switch valve is closed, and when the proportional flow compensation valve is switched on, the oil return switch valve is switched on.
Preferably, the auxiliary actuator is an auxiliary single-acting oil cylinder, the auxiliary oil path working port is further connected to the oil tank through a pressure compensation proportional valve, when the auxiliary single-acting oil cylinder rises, the auxiliary switch valve is turned on, the pressure compensation proportional valve is closed, when the auxiliary single-acting oil cylinder falls, the auxiliary switch valve is closed, and the pressure compensation proportional valve is turned on.
Preferably, the multi-actuator valve block further comprises an auxiliary oil way oil return port connected with the oil tank, and the multi-actuator valve block is connected with the auxiliary oil way oil return port.
Preferably, the anti-channeling check valve is further included, an inlet of the anti-channeling check valve is connected with an oil path between the auxiliary switch valve and the auxiliary oil path working port, and an outlet of the anti-channeling check valve is connected with an oil path between the oil pump and the priority compensating valve.
The invention provides a multi-working-condition safety pressure-adjustable forklift hydraulic system which comprises an oil tank, an oil pump and a priority compensation valve, wherein an output port of the oil pump is connected with an inlet of the priority compensation valve, two outlets of the priority compensation valve are respectively connected with an inlet of a main switch valve and an inlet of an auxiliary switch valve, an outlet of the main switch valve is connected with a main oil way working port of the system, the main oil way working port is connected with a main actuator, an outlet of the auxiliary switch valve is connected with an auxiliary oil way working port of the system, the auxiliary oil way working port is connected with an auxiliary actuator or a multi-actuator valve block, an oil way between the oil pump and the priority compensation valve is connected with the oil tank through a main overflow valve, an oil way between the auxiliary switch valve and the auxiliary oil way working port is connected with the oil tank through a proportional overflow valve, and overflow pressure parameters of the proportional overflow valve are adjusted and set according to working conditions of the auxiliary oil way working port.
Through controlling the priority compensation valve, the main oil way and the auxiliary oil way can work independently or jointly respectively, combined operation is realized, meanwhile, when the working port of the auxiliary oil way is connected with the valve blocks of the multiple actuators, all the joints can share a proportional overflow valve as a safety valve, corresponding parameters are set according to corresponding working conditions, adaptive safe overflow pressure is provided, automatic switching is realized, manual mechanical setting is avoided, the number of the independently-arranged safe overflow valves is reduced compared with the prior art, the condition that one safe overflow valve is shared by multiple joints is also avoided, the flow of all the joints of the auxiliary oil way is stable, the speed is easy to control, the combined operation stability is improved, a hydraulic system is more integrated and compact, meanwhile, all the joints of the actuators of the valve blocks of the multiple actuators are prevented from overflowing under the same high safe overflow parameter, and unnecessary loss is reduced.
Drawings
Fig. 1 is a hydraulic schematic diagram of a specific implementation of the multi-operating-condition safety pressure-adjustable forklift hydraulic system provided by the invention.
The system comprises an oil tank 1, an oil pump 2, a priority compensating valve 3, a main on-off valve 4, an auxiliary on-off valve 5, a main overflow valve 6, a proportional overflow valve 7, a throttle valve 8, an auxiliary on-off valve 9, a proportional flow compensating valve 10, an oil return on-off valve 11, a pressure compensating proportional valve 12, an anti-channeling check valve 13, a main oil way working port A, an auxiliary oil way working port B and an auxiliary oil way oil return port T.
Detailed Description
The core of the invention is to provide a forklift hydraulic system with adjustable multi-working-condition safety pressure, which is provided with a main oil path and an auxiliary oil path, is provided with a proportional overflow valve, provides adaptive safety overflow pressure for different working conditions by adjusting the proportional overflow valve, improves the control accuracy, saves space and saves energy consumption.
In order that those skilled in the art will better understand the disclosure, reference will now be made in detail to the embodiments of the disclosure as illustrated in the accompanying drawings.
Referring to fig. 1, fig. 1 is a hydraulic schematic diagram of an embodiment of a hydraulic system of a forklift truck with adjustable multi-operating-condition safety pressure provided by the present invention.
The invention provides a multi-working-condition safety pressure-adjustable forklift hydraulic system which is applied to forklift equipment and comprises an oil tank 1, an oil pump 2, a priority compensation valve 3, a main switch valve 4, an auxiliary switch valve 5, a main overflow valve 6 and a proportional overflow valve 7, wherein an input port of the oil pump 2 is connected with the oil tank 1, an output port of the oil pump 2 is connected with an inlet of the priority compensation valve 3, a motor drives the oil pump 2 to work, hydraulic oil in the oil tank 1 is output to the priority compensation valve 3, the priority compensation valve 3 is provided with two outlets which are respectively connected with an inlet of the main switch valve 4 and an inlet of the auxiliary switch valve 5, the priority compensation valve 3 is a hydraulic control valve, and the opening degree of the hydraulic oil is controlled to enable the hydraulic oil to independently enter the main switch valve 4 or independently enter the auxiliary switch valve 5 or simultaneously enter the main switch valve 4 and the auxiliary switch valve 5. Furthermore, a main oil path working port A of an outlet connecting system of the main switch valve 4, an auxiliary oil path working port B of an outlet connecting system of the auxiliary switch valve 5, and the main switch valve 4 and the auxiliary switch valve 5 are electromagnetic valves, and are controlled to switch between a conducting state and a closing state through electric signals, so that hydraulic oil can reach the main oil path working port A through the main switch valve 4 and then enter a main actuator connected with the main oil path working port A, or can reach the auxiliary oil path working port B through the auxiliary switch valve 5 and then enter an auxiliary actuator or a multi-actuator valve block connected with the auxiliary oil path working port B. In order to improve the safety, an oil path between the oil pump 2 and the priority compensation valve 3 is connected with the oil tank 1 through a main overflow valve 6, an oil path between an auxiliary switch valve 5 and an auxiliary oil path working port B is connected with the oil tank 1 through a proportional overflow valve 7, and the auxiliary switch valve 5 can be a proportional control valve to improve the output precision. The proportional overflow valve 7 is an electric control valve, and overflow pressure parameters of the proportional overflow valve 7 are adjusted according to the working condition of the auxiliary oil way working port B. Specifically, can preset overflow pressure parameter, can control the settlement in advance through the signal of telecommunication, do not need on-the-spot manual mechanical adjustment, also can be according to the real-time regulation of operating mode change in work, promote degree of automation.
The working process is as follows: when the main oil way works independently, the priority compensating valve 3 is switched to a first working position under the action of control oil, the main switch valve 4 is switched on, the auxiliary switch valve 5 is closed, hydraulic oil sequentially passes through the priority compensating valve 3 and the main switch valve 4 to reach a main oil way working port A, a main actuator is driven to work, at the moment, the main overflow valve 6 is a safety valve of the main oil way, the highest load pressure of the main oil way is limited, and the safety of the main oil way is guaranteed. When the auxiliary oil way works independently, the priority compensating valve 3 is switched to a second working position under the action of control oil, the main switch valve 4 is closed, the auxiliary switch valve 5 is switched on, and hydraulic oil reaches an auxiliary oil way working port B through the priority compensating valve 3 and the auxiliary switch valve in sequence to drive the auxiliary actuator to work. At the moment, the proportional overflow valve 7 is a safety valve of the auxiliary oil way, limits the highest load pressure of the auxiliary oil way, ensures the safety of the auxiliary oil way, and sets different overflow pressure parameters through controlling current so as to adapt to different working conditions. When the main oil way and the auxiliary oil way work simultaneously, two outlets of the priority compensating valve 3 are conducted simultaneously, the main switch valve 4 is conducted, the auxiliary switch valve 5 is conducted, hydraulic oil is divided into two ways at the priority compensating valve 3 and respectively reaches a main oil way working port A and an auxiliary oil way working port B through the main switch valve 4 and the auxiliary switch valve 5, and the main overflow valve 6 and the proportional overflow valve 7 work simultaneously.
Through controlling the priority compensating valve 3, the main oil circuit and the auxiliary oil circuit can work independently or jointly respectively, joint operation is realized, meanwhile, when the auxiliary oil circuit working port B is connected with a plurality of actuator valve blocks, all the joints can share the proportional overflow valve 7 as a safety valve, corresponding parameters are set according to corresponding working conditions, adaptive safe overflow pressure is provided, automatic switching is realized, manual mechanical setting is avoided, the number of the independently-arranged safe overflow valves is reduced compared with the prior art, the condition that one safe overflow valve is shared in multiple joints is also avoided, the flow of all the joints of the auxiliary oil circuit is stable, the speed is easy to control, joint operation stability is improved, a hydraulic system is enabled to be more integrated and compact, meanwhile, the situation that all the joints of the actuators of the plurality of actuator valve blocks overflow under the same high safe overflow parameter is avoided, and unnecessary loss is reduced.
Further, the priority compensation valve 3 is specifically a proportional control compensation valve for adjusting and controlling the flow rate output to the main switching valve 4 and the auxiliary switching valve 5, so that the output is more accurate. The oil path between the auxiliary switch valve 5 and the auxiliary oil path working port B is also connected with the oil tank 1 through a plurality of throttle valves 8 which are connected in series, and the proportional overflow valve 7 is connected with at least one throttle valve 8 in parallel. The proportional overflow valve 7, the throttle valve 8 and the priority compensating valve 3 are combined together to be used as a safety valve of an auxiliary oil path, when an auxiliary actuator connected with an auxiliary oil path working port B is an auxiliary single-action oil cylinder, and during lifting action, the proportional overflow valve 7, the throttle valve 8 and the priority compensating valve 3 are combined to enable the flow and pressure of the auxiliary single-action oil cylinder to be free from being influenced by load change and to be relatively stable during lifting action. Meanwhile, when the main oil way and the auxiliary oil way work together, under the combined action of the priority compensating valve 3 and the throttle valve 8, the problem of action time difference of the main actuator and the auxiliary actuator caused by large load difference of the main oil way and the auxiliary oil way can be solved, and the simultaneous descending of the single-acting oil cylinders of the main oil way and the auxiliary oil way is not different from the independent descending of the single-acting oil cylinders of the main oil way and the auxiliary oil way. When the auxiliary oil circuit working port B is externally connected with a plurality of actuator valve blocks which are connected in parallel or in series, the lifting connection of the external valve block can be only provided with one electromagnetic switch valve, and the external valve blocks can simultaneously share the combination of the proportional overflow valve 7, the throttle valve 8 and the priority compensating valve 3 as the oil inlet safety overflow valve of the external valve block. The combination can be set according to the safety overflow parameters corresponding to the corresponding working conditions of each connection of the external valve block, and when a control signal designates a certain connection to work independently, the pressure parameters can be automatically switched; when the external valve blocks are connected in parallel or in series to carry out combined operation, safety parameter setting can be carried out according to actual combined operation working conditions, and meanwhile, the flow of the auxiliary oil way is reasonably adjusted by the preferential compensation valve 3 under each working condition, so that the flow change of the auxiliary oil way is more reasonable.
In order to ensure the working flow of the main oil path, the priority compensation valve 3 is provided with a monostable shunt passage connected with the main switch valve 4, and the oil path between the priority compensation valve 3 and the main switch valve 4 is connected with the oil tank 1 through an auxiliary switch valve 9. When the main oil circuit works independently or the main oil circuit and the auxiliary oil circuit work together, the auxiliary switch valve 9 is closed, hydraulic oil can enter the main switch valve 4 through the monostable shunt channel, when the auxiliary oil circuit works independently, the auxiliary switch valve 9 is conducted, the hydraulic oil directly flows back to the oil tank 1 through the auxiliary switch valve 9 after entering the monostable shunt channel, and pressure cannot be applied to the main switch valve 4.
Further, the main actuator is specifically a main single-acting oil cylinder, in order to realize smooth descending of the main single-acting oil cylinder, the main oil way working port a is also connected with the oil tank 1 through the proportional flow compensation valve 10, when the main single-acting oil cylinder rises, the main switch valve 4 is switched on, the proportional flow compensation valve 10 is switched off, the auxiliary switch valve 9 is switched off, and hydraulic oil reaches the main oil way working port a through the main switch valve 4 and enters the main single-acting oil cylinder. When the main single-acting oil cylinder descends, the main switch valve 4 is closed, the proportional flow compensation valve 10 is conducted, the auxiliary switch valve 9 is conducted, and hydraulic oil in the main single-acting oil cylinder flows back to the oil tank 1 through the main oil way working port A and the proportional flow compensation valve 10 under the action of load and self gravity.
Preferably, an oil return switch valve 11 is disposed at an outlet of the proportional flow compensation valve 10, when the proportional flow compensation valve 10 is closed, the oil return switch valve 11 is closed, and when the proportional flow compensation valve 10 is turned on, the oil return switch valve 11 is turned on. Namely, an electromagnetic switch valve is arranged at the outlet of the proportional flow compensation valve 10, so that double insurance is provided.
The auxiliary actuator is specifically an auxiliary single-acting oil cylinder, in order to realize the smooth descending of the auxiliary single-acting oil cylinder, an auxiliary oil way working port B is also connected with the oil tank 1 through a pressure compensation proportional valve 12, when the auxiliary single-acting oil cylinder rises, an auxiliary switch valve 5 is conducted, the pressure compensation proportional valve 12 is closed, and hydraulic oil reaches the auxiliary oil way working port B through the auxiliary switch valve 5 and enters the auxiliary single-acting oil cylinder. When the auxiliary single-action oil cylinder descends, the auxiliary switch valve 5 is closed, the pressure compensation proportional valve 12 is conducted, and hydraulic oil in the auxiliary single-action oil cylinder flows back to the oil tank 1 through the auxiliary oil way working port B and the pressure compensation proportional valve 12 under the action of load and self gravity. The descending oil passages of the main and auxiliary oil passages of the hydraulic system are all provided with pressure and flow compensation valves, so that the descending speed is only influenced by valve control, manual unloading is added to the pressure and flow compensation valves of the descending oil passages of the main and auxiliary oil passages, the descending speed can be prevented from changing due to load change, and the speed can be adjusted.
The oil tank also comprises an auxiliary oil way oil return port T connected with the oil tank 1, when the auxiliary oil way working port B is externally connected with a plurality of actuator valve blocks which are connected in parallel or in series, the lifting and descending actions of the lifting connection in the valve blocks of the plurality of actuators are the same as the conditions when the auxiliary oil way working port B is directly connected with an auxiliary single-acting oil cylinder, all the connection oil returns except the lifting connection can be externally connected with a pipeline for oil return, and can also be connected with the auxiliary oil way oil return port T to share one path of oil return with hydraulic pressure
On the basis of the forklift hydraulic system with adjustable multi-working-condition safety pressure provided by each specific embodiment, the forklift hydraulic system further comprises a channeling-preventing one-way valve 13, wherein an inlet of the channeling-preventing one-way valve 13 is connected with an oil way between the auxiliary switch valve 5 and the auxiliary oil way working port B, and an outlet of the channeling-preventing one-way valve 13 is connected with an oil way between the oil pump 2 and the priority compensation valve 3. When the auxiliary oil way working port B is externally connected with the multiple-actuator valve blocks in parallel or in series, in order to avoid causing other linkage play when one linkage of the multiple-actuator valve blocks works, the problem is solved by arranging the anti-play one-way valve 13, when oil trapping occurs or the play is caused by overlarge flow, the anti-play one-way valve 13 is used for returning and supplementing oil to redundant oil, the oil channeling problem can be solved, oil can be supplemented, and the flow is ensured. Preferably, a check valve may be added at a suitable position of the hydraulic system to prevent oil return, and the valves may be electrically controlled, hydraulically controlled, or the type of the valve may be adjusted according to the situation, all of which are within the protection scope of the present invention.
The specific working process is as follows: when the main oil way works independently, the oil pump 2 works to absorb oil, the auxiliary switch valve 9 is switched to the lower position to be closed, the priority compensation valve 3 is switched to the left position under the action of control oil, the main switch valve 4 is switched to the right position to be conducted, the auxiliary switch valve 5 is switched to the right position to be closed, the proportional flow compensation valve 10 is closed, the oil return switch valve 11 is closed, hydraulic oil sequentially passes through the priority compensation valve 3 and the main switch valve 4 to reach a main oil way working opening A to drive the main single-acting oil cylinder to lift, and at the moment, the main overflow valve 6 is a safety valve of the main oil way. When the main single-acting oil cylinder descends, the main switch valve 4 is switched to the left position to be closed, the proportional flow compensation valve 10 is switched on, the oil return switch valve 11 is switched on, and hydraulic oil in the main single-acting oil cylinder flows back to the oil tank 1 through the main oil way working port A, the proportional flow compensation valve 10 and the oil return switch valve 11 under the action of load and self gravity.
When the auxiliary oil way works independently, the oil pump 2 works to absorb oil, the auxiliary switch valve 9 is switched to be switched to the upper position to be switched on, the priority compensation valve 3 is switched to the right position under the action of control oil, the main switch valve 4 is switched to the left position to be closed, the auxiliary switch valve 5 is switched to the left position to be switched on, the pressure compensation proportional valve 12 is closed, hydraulic oil sequentially passes through the priority compensation valve 3 and the main switch valve 4 to reach an auxiliary oil way working opening B to drive the auxiliary single-acting oil cylinder to lift, and at the moment, the proportional overflow valve 7 is a safety valve of the auxiliary oil way. When the auxiliary single-acting oil cylinder descends, the auxiliary switch valve 5 is switched to the right position to be closed, the pressure compensation proportional valve 12 is conducted, and hydraulic oil in the auxiliary single-acting oil cylinder flows back to the oil tank 1 through the auxiliary oil way working port B and the pressure compensation proportional valve 12 under the action of load and self gravity.
When the main oil way and the auxiliary oil way work simultaneously, two outlets of the priority compensation valve 3 are conducted simultaneously, when the main single-action oil cylinder and the auxiliary single-action oil cylinder rise simultaneously, the auxiliary switch valve 5 is switched to the left position to be conducted, the main switch valve 4 is switched to the right position to be conducted, the auxiliary switch valve 9 is switched to the lower position to be closed, hydraulic oil is divided into two paths at the priority compensation valve 3 and respectively reaches a main oil way working port A and an auxiliary oil way working port B through the main switch valve 4 and the auxiliary switch valve 5, the main overflow valve 6 and the proportional overflow valve 7 work simultaneously, and when the main single-action oil cylinder and the auxiliary single-action oil cylinder fall simultaneously, all the valves can act reversely.
In addition to the forklift hydraulic system, a specific embodiment of the present invention further provides a forklift including the forklift hydraulic system, and the structure of other parts of the forklift refers to the prior art, which is not described herein again.
In particular, the above-mentioned forklift may be a reach forklift, a stacking forklift and a side forklift.
The forklift hydraulic system with the multi-working-condition safety and adjustable pressure provided by the invention is described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
Claims (10)
1. The utility model provides a fork truck hydraulic system that multiplex condition safety pressure is adjustable, its characterized in that, includes oil tank (1), oil pump (2) and preferential compensating valve (3), the delivery outlet of oil pump (2) is connected the import of preferential compensating valve (3), two exports of preferential compensating valve (3) are connected with the import of main switch valve (4) and the import of vice ooff valve (5) respectively, the main oil circuit working opening (A) of the exit linkage system of main switch valve (4), main executor is connected to main oil circuit working opening (A), the vice oil circuit working opening (B) of the exit linkage system of vice ooff valve (5), vice oil circuit working opening (B) is connected vice executor or many executor valve blocks, oil pump (2) with the oil circuit between preferential compensating valve (3) passes through main overflow valve (6) and connects oil tank (1), vice ooff valve (5) with the oil circuit working opening (B) between pass through proportional overflow valve (7) and connect oil tank (1), and according to the operating mode setting of vice oil circuit (B) overflow valve (7) the proportion overflow valve (7) overflow pressure parameter.
2. The multi-operating-condition safety pressure-adjustable forklift hydraulic system according to claim 1, wherein the priority compensation valve (3) is a proportional control compensation valve for controlling the flow output to the main switching valve (4) and the auxiliary switching valve (5).
3. The multi-operating-condition safety pressure-adjustable forklift hydraulic system according to claim 2, characterized in that the oil path between the secondary on-off valve (5) and the secondary oil path working port (B) is further connected with the oil tank (1) through a plurality of throttle valves (8) connected in series, and the proportional overflow valve (7) is connected in parallel with at least one throttle valve (8).
4. A multi-operating-condition safety pressure-adjustable forklift hydraulic system according to claim 3, characterized in that the secondary on-off valve (5) is embodied as a proportional regulating valve.
5. The multi-operating-condition safety pressure-adjustable forklift hydraulic system according to claim 4, characterized in that the priority compensating valve (3) is provided with a monostable shunt passage connected with the main switch valve (4), and an oil path between the priority compensating valve (3) and the main switch valve (4) is connected with the oil tank (1) through an auxiliary switch valve (9).
6. The forklift hydraulic system with the adjustable multi-operating-condition safety pressure as claimed in claim 5, wherein the main actuator is a main single-acting cylinder, the main oil way working port (A) is further connected with the oil tank (1) through a proportional flow compensation valve (10), when the main single-acting cylinder rises, the main switch valve (4) is switched on, the proportional flow compensation valve (10) is closed, the auxiliary switch valve (9) is closed, when the main single-acting cylinder descends, the main switch valve (4) is closed, the proportional flow compensation valve (10) is switched on, and the auxiliary switch valve (9) is switched on.
7. The forklift hydraulic system with the adjustable multi-operating-condition safety pressure as claimed in claim 6, wherein an oil return switch valve (11) is arranged at an outlet of the proportional flow compensation valve (10), when the proportional flow compensation valve (10) is closed, the oil return switch valve (11) is closed, and when the proportional flow compensation valve (10) is conducted, the oil return switch valve (11) is conducted.
8. The forklift hydraulic system with the adjustable multi-operating-condition safety pressure as claimed in claim 1, wherein the auxiliary actuator is specifically an auxiliary single-acting oil cylinder, the auxiliary oil circuit working port (B) is further connected with the oil tank (1) through a pressure compensation proportional valve (12), when the auxiliary single-acting oil cylinder rises, the auxiliary switch valve (5) is switched on, the pressure compensation proportional valve (12) is closed, when the auxiliary single-acting oil cylinder falls, the auxiliary switch valve (5) is closed, and the pressure compensation proportional valve (12) is switched on.
9. The multi-operating-condition safety pressure-adjustable forklift hydraulic system according to claim 1, further comprising an auxiliary oil way return port (T) connected to the oil tank (1), and a multi-actuator valve block connected to the auxiliary oil way return port (T).
10. The forklift hydraulic system with the adjustable multi-operating-condition safety pressure as claimed in any one of claims 1 to 9, further comprising a float-preventing check valve (13), wherein an inlet of the float-preventing check valve (13) is connected with an oil path between the auxiliary switch valve (5) and the auxiliary oil path working port (B), and an outlet of the float-preventing check valve (13) is connected with an oil path between the oil pump (2) and the priority compensation valve (3).
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| CN202211652052.8A CN115898987A (en) | 2022-12-22 | 2022-12-22 | Multi-working-condition safety pressure-adjustable forklift hydraulic system |
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| CN202211652052.8A CN115898987A (en) | 2022-12-22 | 2022-12-22 | Multi-working-condition safety pressure-adjustable forklift hydraulic system |
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| CN202482016U (en) * | 2012-03-14 | 2012-10-10 | 安徽合力股份有限公司 | Diesel fork lift truck hydraulic system with safety protection mechanism |
| CN107882792A (en) * | 2017-11-10 | 2018-04-06 | 广西柳工机械股份有限公司 | Unloading electromagnetic valve and loader dual-pump combining hydraulic system |
| CN113357210A (en) * | 2021-06-28 | 2021-09-07 | 三一汽车起重机械有限公司 | Cylinder arm pin hydraulic control system with flow compensation function and operation machine |
| CN217582718U (en) * | 2022-05-18 | 2022-10-14 | 山东临工工程机械有限公司 | Energy-saving hydraulic system of road roller |
| CN115370633A (en) * | 2022-08-25 | 2022-11-22 | 乐卓液压科技(苏州)有限公司 | Fork truck and integrated hydraulic control system thereof |
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