CN112576559A - Hydraulic circuit - Google Patents
Hydraulic circuit Download PDFInfo
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- CN112576559A CN112576559A CN202010879128.5A CN202010879128A CN112576559A CN 112576559 A CN112576559 A CN 112576559A CN 202010879128 A CN202010879128 A CN 202010879128A CN 112576559 A CN112576559 A CN 112576559A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2264—Arrangements or adaptations of elements for hydraulic drives
- E02F9/2267—Valves or distributors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/022—Flow-dividers; Priority valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/026—Pressure compensating valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/027—Check valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/06—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B19/00—Testing; Calibrating; Fault detection or monitoring; Simulation or modelling of fluid-pressure systems or apparatus not otherwise provided for
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
- F15B2211/205—Systems with pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/50—Pressure control
- F15B2211/505—Pressure control characterised by the type of pressure control means
- F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/50—Pressure control
- F15B2211/51—Pressure control characterised by the positions of the valve element
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/50—Pressure control
- F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
本发明的液压回路优先向连接于上游侧液压回路的致动器供给压力油。液压回路包括上游侧液压回路和下游侧液压回路。上游侧液压回路具有从液压泵供给有压力油的上游侧串联线路和上游侧并联线路、串联地连接于上游侧串联线路且并联地连接于上游侧并联线路的上游侧切换阀、以及连接于上游侧并联线路的上游侧卸载阀。下游侧液压回路具有借助上游侧液压回路的上游侧卸载阀连接于上游侧并联线路的下游侧串联线路、连接于上游侧液压回路的上游侧串联线路的下游侧并联线路、串联地连接于下游侧串联线路且并联地连接于下游侧并联线路的下游侧切换阀、以及位于下游侧并联线路和罐线路之间的下游侧卸载阀。
The hydraulic circuit of the present invention preferentially supplies pressurized oil to the actuator connected to the upstream hydraulic circuit. The hydraulic circuit includes an upstream-side hydraulic circuit and a downstream-side hydraulic circuit. The upstream-side hydraulic circuit includes an upstream-side series line and an upstream-side parallel line to which pressure oil is supplied from a hydraulic pump, an upstream-side switching valve connected in series to the upstream-side series line and connected in parallel to the upstream-side parallel line, and an upstream-side switching valve connected to the upstream side. The upstream side unloading valve of the side parallel line. The downstream-side hydraulic circuit has a downstream-side series line connected to the upstream-side parallel line via an upstream-side unload valve of the upstream-side hydraulic circuit, a downstream-side parallel line connected to the upstream-side series line of the upstream-side hydraulic circuit, and a downstream-side parallel line connected in series to the downstream side The downstream side switching valve of the downstream side parallel line is connected in series and in parallel, and the downstream side unloading valve located between the downstream side parallel line and the tank line.
Description
Technical Field
The present invention relates to a hydraulic circuit for controlling supply of pressure oil to a plurality of actuators.
Background
A hydraulic circuit is known in which pressure oil discharged from a variable displacement pump is supplied to a plurality of actuators via a switching valve. For example, patent document 1 discloses a hydraulic circuit including a plurality of closed-center type switching valves connected in parallel to a pressure oil supply line of a variable displacement pump. The plurality of switching valves supply pressure oil to the corresponding actuators in accordance with the opening degrees of the throttle provided in the actuator lines of the switching valves.
Documents of the prior art
Patent document
Patent document 1: japanese laid-open patent publication No. 9-79212
Disclosure of Invention
Problems to be solved by the invention
In construction machines such as excavators and cranes, it is sometimes desired to configure a hydraulic circuit so that a plurality of actuators used in the construction machine are not affected by each other for safety reasons.
The present invention aims to provide a hydraulic circuit that can effectively solve such problems.
Means for solving the problems
The hydraulic circuit of the present invention includes:
an upstream side hydraulic circuit having an upstream side series line and an upstream side parallel line to which pressure oil is supplied from a hydraulic pump, an upstream side switching valve connected in series to the upstream side series line and connected in parallel to the upstream side parallel line, and an upstream side unloading valve connected to the upstream side parallel line; and
a downstream side hydraulic circuit having a downstream side series line connected to the upstream side parallel line via the upstream side unloading valve of the upstream side hydraulic circuit, a downstream side parallel line connected to the upstream side series line of the upstream side hydraulic circuit, a downstream side switching valve connected in series to the downstream side series line and connected in parallel to the downstream side parallel line, and a downstream side unloading valve located between the downstream side parallel line and a tank line.
In the hydraulic circuit of the present invention, the upstream-side switching valve may include a bypass line connected to the upstream-side series line and an actuator line connected to the upstream-side parallel line and through which pressure oil supplied to the corresponding actuator passes.
In the hydraulic circuit according to the present invention, the downstream side switching valve may include a bypass line connected to the downstream side series line and an actuator line connected to the downstream side parallel line and through which pressure oil supplied to the corresponding actuator passes.
In the hydraulic circuit according to the present invention, the upstream side hydraulic circuit may include an upstream side highest pressure detection line connected in parallel to an actuator line of the upstream side switching valve via a check valve and connected to the upstream side unloading valve so as to act in a direction of a closed position at the upstream side unloading valve.
In the hydraulic circuit according to the present invention, the upstream-side highest pressure detection line may be connected to a pressure compensating valve through the check valve so as to act in a closed position direction on the pressure compensating valve connected in series to the actuator line of the upstream switching valve of the upstream-side hydraulic circuit.
In the hydraulic circuit according to the present invention, the downstream side hydraulic circuit may include a downstream side maximum pressure detection line connected in parallel to the actuator line of the downstream side switching valve via a check valve and connected to the downstream side unloading valve so as to act in a closed position direction at the downstream side unloading valve.
In the hydraulic circuit according to the present invention, the downstream-side maximum pressure detection line may be connected to a pressure compensating valve via the check valve so as to act in a closed position direction on the pressure compensating valve connected in series to the actuator line of the downstream-side switching valve of the downstream-side hydraulic circuit.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, pressure oil can be preferentially supplied to the actuator connected to the upstream hydraulic circuit.
Drawings
Fig. 1 is a diagram showing a hydraulic circuit according to an embodiment.
Fig. 2 is an enlarged view of an upstream side hydraulic circuit of the hydraulic circuit of fig. 1.
Fig. 3 is an enlarged view of a downstream side hydraulic circuit of the hydraulic circuit of fig. 1.
Description of the reference numerals
1. A hydraulic circuit (hydraulic circuit); 2. a hydraulic pump (hydraulic pump); 3. high pressure line (high pressure line); 5. a tank (tank); 6. a tank line (tank line); 11. a 1 st actuator (first actuator); 12. a 2 nd actuator (second actuator); 13. a 3 rd actuator (third actuator); 14. a 4 th actuator (four actuator); 20. an upstream hydraulic circuit (upstream hydraulic circuit); 21. an upstream side series line (upstream series line); 22. an upstream parallel line (upstream parallel line); 23. an upstream unloading valve (upstream unloading valve); 24. an upstream maximum-pressure-detecting line (upstream maximum-pressure-detecting line); 25. a throttle (throttle); 30. an upstream switching valve (upstream switching valve); 31. a pressure-compensating valve; 32. a maximum-pressure-detecting check valve (maximum-pressure-detecting check valve); 33. load-holding check valve; 35. an upstream switching valve (upstream switching valve); 36. a pressure-compensating valve; 37. a maximum-pressure-detecting check valve (maximum-pressure-detecting check valve); 38. load-holding check valve; 40. a downstream hydraulic circuit (downstream hydraulic circuit); 41. a downstream side series line (downstream side series line); 42. a downstream parallel line (downstream parallel line); 43. a downstream unloading valve (downstream unloading valve); 44. a downstream maximum-pressure-detecting line (downstream maximum-pressure-detecting line); 45. a throttle (throttle); 50. a downstream switching valve (downstream switching valve); 51. a pressure-compensating valve; 52. a maximum-pressure-detecting check valve (maximum-pressure-detecting check valve); 53. load-holding check valve; 55. a downstream switching valve (downstream switching valve); 56. a pressure-compensating valve; 57. a maximum-pressure-detecting check valve (maximum-pressure-detecting check valve); 58. load-holding check valve.
Detailed Description
First, problems to be solved by the hydraulic circuit 1 according to the embodiment of the present invention will be described.
For safety reasons, construction machines such as excavators and cranes need to be provided with an interlock function that cannot be operated simultaneously on the machine, and an independent circuit in which a plurality of actuators are not affected by each other. For example, in a small-sized excavating machine used in a city, in order to prevent a collision accident during a turning process, it is preferable that a circuit for supplying pressure oil to an actuator for turning drive is independent from other circuits. In the case where the generator is driven by the hydraulic motor, in order to stabilize the electric performance of the generator, it is preferable that a circuit for supplying the hydraulic oil to the hydraulic motor is configured independently of the other circuits, and variation in the rotation speed of the hydraulic motor is prevented. On the other hand, the conventional load sensing hydraulic control valve supplies hydraulic pressure to the actuator in accordance with the opening degree of the spool. Therefore, when a plurality of control valves are provided in parallel in the pressure oil supply line of the variable displacement pump, the plurality of actuators are affected by changes in pressure and flow rate between the actuators.
In order to solve such a problem, the present embodiment proposes: the hydraulic circuit 1 includes an upstream side hydraulic circuit 20 and a downstream side hydraulic circuit 40 having a series circuit of an open center type and a parallel circuit of a closed center type. Specifically, there are proposed: the hydraulic circuit 1 is configured such that the series circuit of the upstream side hydraulic circuit 20 is connected to the parallel circuit of the downstream side hydraulic circuit 40, and the parallel circuit of the upstream side hydraulic circuit 20 is connected to the series circuit of the downstream side hydraulic circuit 40. In this case, when the upstream switching valve of the upstream hydraulic circuit 20 is operated, the series circuit of the upstream hydraulic circuit 20 is blocked, and therefore, the pressure oil is not supplied to the downstream hydraulic circuit 40. This can prevent the actuator connected to the upstream hydraulic circuit 20 from being affected by changes in the pressure and flow rate of the actuator connected to the downstream hydraulic circuit 40.
Hereinafter, the hydraulic circuit 1 according to the embodiment of the present invention will be described in detail with reference to the drawings. The embodiments described below are merely examples of the embodiments of the present invention, and the present invention is not to be construed as being limited to these embodiments. In the drawings referred to in the present embodiment, the same reference numerals or similar reference numerals are given to the same portions or portions having the same functions, and redundant description thereof may be omitted. For convenience of explanation, the dimensional ratios in the drawings may be different from the actual ratios, and parts of the structures may be omitted from the drawings.
Hydraulic circuit
Fig. 1 is a diagram showing a hydraulic circuit 1 according to the present embodiment. The hydraulic circuit 1 includes a hydraulic pump 2, a high-pressure line 3, an upstream side hydraulic circuit 20, a downstream side hydraulic circuit 40, a tank line 6, and a tank 5. In the present embodiment, a case where the hydraulic pump 2 is a single pump having 1 discharge port will be described. The hydraulic pump 2 is connected to the upstream hydraulic circuit 20 via a high-pressure line 3. The pressure oil supplied from the hydraulic pump 2 to the upstream hydraulic circuit 20 via the high-pressure line 3 is supplied to the downstream hydraulic circuit 40 after passing through the upstream hydraulic circuit 20. The pressure oil supplied to the upstream side hydraulic circuit 20 and the downstream side hydraulic circuit 40 is returned to the tank 5 via the tank line 6. As the hydraulic pump 2, various pumps other than the single pump may be used.
Upstream side hydraulic circuit
The upstream hydraulic circuit 20 has at least an upstream series line 21, an upstream parallel line 22, a plurality of upstream switching valves 30, 35, an upstream unloading valve 23, an upstream maximum pressure detection line 24, and a throttle 25. The pressure oil is supplied from the hydraulic pump 2 to the upstream side series line 21 and the upstream side parallel line 22 via the high-pressure line 3, respectively. The upstream-side series line 21 and the upstream-side parallel line 22 are connected to the upstream- side switching valves 30, 35, respectively. The upstream switching valves 30 and 35 supply pressure oil to the corresponding actuators 11 and 12, respectively. The actuators 11, 12 are not particularly limited, and are, for example, hydraulic motors.
Fig. 2 is an enlarged view of the upstream hydraulic circuit 20. The upstream switching valves 30 and 35 of the upstream hydraulic circuit 20 can take neutral positions 30x and 35x, 1 st operating positions 30y and 35y, or 2 nd operating positions 30z and 35z by moving a spool, not shown. In the 1 st operating positions 30y and 35y, the pressure oil from the upstream- side switching valves 30 and 35 is supplied to the 1 st ports 11a and 12a of the actuators 11 and 12, and then the pressure oil is discharged from the 2 nd ports 11b and 12b and returned to the tank 5 via the tank line 6. In the 2 nd operating positions 30z, 35z, the pressure oil from the upstream- side switching valves 30, 35 is supplied to the 2 nd ports 11b, 12b of the actuators 11, 12, and then the pressure oil is discharged from the 1 st ports 11a, 12a and returned to the tank 5 via the tank line 6. In the following description, the 1 st operating positions 30y and 35y and the 2 nd operating positions 30z and 35z may be collectively referred to as the operating positions.
The upstream- side switching valves 30, 35 include at least bypass lines 30a, 35a and actuator lines 30b, 35 b. The bypass lines 30a and 35a are connected in series to the upstream-side series line 21. The bypass line 30a of the upstream-side switching valve 30 is located upstream of the bypass line 35a of the upstream-side switching valve 35.
The upstream- side switching valves 30 and 35 are of a so-called open-heart type. Therefore, when the upstream- side switching valves 30 and 35 are in the neutral positions 30x and 35x, the pressurized oil in the upstream-side series line 21 can pass through the bypass line 30a of the upstream-side switching valve 30 and the bypass line 35a of the upstream-side switching valve 35 in this order.
The actuator lines 30b and 35b are connected in parallel to the upstream parallel line 22.
When the upstream- side switching valves 30 and 35 are in the 1 st operating positions 30y and 35y, the pressure oil reaching the upstream- side switching valves 30 and 35 from the upstream-side parallel line 22 passes through the actuator lines 30b and 35b and is then supplied to the 1 st ports 11a and 12a of the actuators 11 and 12. After that, the pressure oil passes through the actuator lines 30b, 35b of the upstream- side switching valves 30, 35 after being discharged from the 2 nd ports 11b, 12b, and is returned to the tank 5 via the tank line 6.
When the upstream- side switching valves 30 and 35 are in the 2 nd operating positions 30z and 35z, the pressure oil reaching the upstream- side switching valves 30 and 35 from the upstream-side parallel line 22 passes through the actuator lines 30b and 35b and is then supplied to the 2 nd ports 11b and 12b of the actuators 11 and 12. After that, the pressure oil passes through the actuator lines 30b, 35b of the upstream- side switching valves 30, 35 after being discharged from the 1 st ports 11a, 12a, and is returned to the tank 5 via the tank line 6.
The upstream unloading valve 23 is connected to the upstream parallel line 22 at an upstream side port and connected to the downstream series line 41 at a downstream side port. The upstream unloading valve 23 acquires the blocking position 23x in a section where the pressure of the hydraulic pressure in the upstream parallel line 22 is equal to or lower than the upstream threshold value, and acquires the unloading position 23y when the pressure of the hydraulic pressure in the upstream parallel line 22 is higher than the upstream threshold value. The upstream side threshold value of the upstream side unloading valve 23 is the sum of the pressure from the spring 23a provided in the upstream side unloading valve 23 and the pressure from the upstream side highest pressure detection line 24 connected to the upstream side unloading valve 23.
The upstream-side highest pressure detection line 24 is connected in parallel to the actuator lines 30b, 35b of the upstream- side switching valves 30, 35, respectively, via highest pressure detection check valves 32, 37. The upstream side highest pressure detection line 24 is connected to the tank line 6 via a throttle 25. The pressure of the upstream side highest pressure detection line 24 is equal to the highest pressure of the actuator lines 30b, 35 b. Further, the upstream side highest pressure detection line 24 is connected to the upstream side unloading valve 23 so as to act in the direction of the closed position at the upstream side unloading valve 23. By providing such an upstream side maximum pressure detection line 24, the hydraulic pressure of the upstream side parallel line 22 can be increased to the sum of the maximum pressure of the actuator lines 30b, 35b and the pressure of the spring 23a when the upstream side switching valves 30, 35 are in the operating positions.
The upstream-side hydraulic circuit 20 may also have pressure compensating valves 31, 36, and the pressure compensating valves 31, 36 are connected in series to the actuator lines 30b, 35b of the upstream- side switching valves 30, 35, respectively, by load holding check valves 33, 38. The upstream-side highest pressure detection line 24 is connected to the pressure compensation valves 31 and 36 via check valves 32 and 37 so as to act in the direction of the closed position at the pressure compensation valves 31 and 36. Therefore, the pressures of the pressurized oil supplied to the actuators 11 and 12 can be equalized. For example, when the pressure of the 1 st actuator 11 is higher than that of the 2 nd actuator 12, the pressure of the 1 st actuator 11 acts in the direction of the closed position as the pressure of the upstream side highest pressure detection line 24 at the pressure compensation valve 36. Therefore, at the pressure compensating valve 36, the pressure of the actuator line 35b increases. This allows the pressure oil to be equally branched to the 1 st actuator 11 and the 2 nd actuator 12.
Downstream side hydraulic circuit
The downstream side hydraulic circuit 40 has at least a downstream side series line 41, a downstream side parallel line 42, a plurality of downstream side switching valves 50, 55, a downstream side unloading valve 43, a downstream side maximum pressure detection line 44, and a throttle 45. The downstream side series line 41 is connected to the upstream side parallel line 22 via the upstream side unloading valve 23 of the upstream side hydraulic circuit 20. The downstream side parallel line 42 is connected to the upstream side series line 21 of the upstream side hydraulic circuit 20. The downstream side series line 41 and the downstream side parallel line 42 are connected to the downstream side switching valves 50, 55, respectively. The downstream- side switching valves 50 and 55 supply pressure oil to the corresponding actuators 13 and 14, respectively. The actuators 13, 14 are not particularly limited, and are, for example, hydraulic cylinders.
Fig. 3 is an enlarged view of the downstream hydraulic circuit 40. The downstream- side switching valves 50 and 55 of the downstream-side hydraulic circuit 40 can obtain neutral positions 50x and 55x, 1 st operating positions 50y and 55y, or 2 nd operating positions 50z and 55z by moving a spool, not shown, in the same manner as the upstream- side switching valves 30 and 35 of the upstream-side hydraulic circuit 20. In the 1 st operating positions 50y and 55y, the pressure oil from the downstream- side switching valves 50 and 55 is supplied to the 1 st ports 13a and 14a of the actuators 13 and 14, and then the pressure oil is discharged from the 2 nd ports 13b and returned to the tank 5 via the tank line 6. In the 2 nd operating positions 50z, 55z, the pressure oil from the downstream side switching valves 50, 55 is supplied to the 2 nd ports 13b, 14b of the actuators 13, 14, and then the pressure oil is discharged from the 1 st ports 13a, 14a and returned to the tank 5 via the tank line 6.
The downstream- side switching valves 50, 55 are open-center type switching valves including at least bypass lines 50a, 55a and actuator lines 50b, 55 b. The bypass lines 50a, 55a are connected in series to the downstream side series line 41. The bypass line 50a of the downstream-side switching valve 50 is located upstream of the bypass line 55a of the downstream-side switching valve 55. The actuator lines 50b, 55b are connected in parallel to the downstream side parallel line 42, respectively. The structures and functions of the downstream- side switching valves 50 and 55 are the same as those of the upstream- side switching valves 30 and 35, and therefore, detailed descriptions thereof are omitted.
The downstream-side unloading valve 43 is connected to the downstream-side parallel line 42 at the upstream-side port and to the tank line 6 at the downstream-side port. The downstream-side unloading valve 43 obtains the blocking position 43x in a section where the pressure of the hydraulic pressure in the downstream-side parallel line 42 is equal to or lower than the downstream-side threshold value, and obtains the unloading position 43y when the pressure of the hydraulic pressure in the downstream-side parallel line 42 is greater than the downstream-side threshold value. The downstream side threshold value of the downstream side unloading valve 43 is the sum of the pressure from the spring 43a provided in the downstream side unloading valve 43 and the pressure from the downstream side highest pressure detection line 44 connected to the downstream side unloading valve 43.
The downstream-side maximum pressure detection line 44 is connected in parallel to the actuator lines 50b, 55b of the downstream- side switching valves 50, 55 via the maximum pressure detection check valves 52, 57, respectively. The downstream side highest pressure detection line 44 is connected to the tank line 6 via a throttle 45. The pressure of the downstream side highest pressure detection line 44 is equal to the highest pressure of the actuator lines 50b, 55 b. Further, the downstream side highest pressure detection line 44 is connected to the downstream side unloading valve 43 so as to act in the direction of the closed position at the downstream side unloading valve 43. By providing such a downstream side maximum pressure detection line 44, it is possible to increase the hydraulic pressure of the downstream side parallel line 42 to the sum of the maximum pressure of the actuator lines 50b, 55b and the pressure of the spring 43a when the downstream side switching valves 50, 55 are in the operating positions.
The downstream side hydraulic circuit 40 may also have pressure compensating valves 51, 56, and the pressure compensating valves 51, 56 are connected in series to the actuator lines 50b, 55b of the downstream side switching valves 50, 55 via load holding check valves 53, 58, respectively. The downstream-side maximum pressure detection line 44 is connected to the pressure compensation valves 51 and 56 via check valves 52 and 57 so as to act in the direction of the closed position at the pressure compensation valves 51 and 56. Therefore, the pressures of the pressurized oil supplied to the actuators 13 and 14 can be equalized. This allows the pressure oil to be equally branched to the 3 rd actuator 13 and the 4 th actuator 14.
Next, the operation and effect of the present embodiment configured as described above will be described. Here, the operation of the hydraulic circuit 1 will be described.
(case where each switching valve is in neutral position)
First, the case where the upstream switching valves 30, 35, 50, and 55 are in the neutral positions 30x, 35x, 50x, and 55x will be described. In this case, the pressure oil supplied from the hydraulic pump 2 and the high-pressure line 3 to the upstream side series line 21 of the upstream side hydraulic circuit 20 reaches the downstream side unloading valve 43 through the bypass lines 30a, 35a of the upstream side switching valves 30, 35 and the downstream side parallel line 42 of the downstream side hydraulic circuit 40. Since no pressure oil is supplied to the actuator lines 50b, 55b, the pressure of the downstream side maximum pressure detection line 44 is substantially equal to the pressure of the tank line 6 connected via the orifice 45. Therefore, the downstream side unload valve 43 takes the unload position 43y by the pressure of the downstream side parallel line 42, and the pressure oil reaching the downstream side unload valve 43 flows into the tank line 6.
On the other hand, the pressure oil supplied from the hydraulic pump 2 and the high-pressure line 3 to the upstream parallel line 22 of the upstream hydraulic circuit 20 reaches the upstream unloading valve 23. Since no pressure oil is supplied to the actuator lines 30b, 35b, the pressure of the upstream side highest pressure detection line 24 is substantially equal to the pressure of the tank line 6 connected via the orifice 25. Therefore, the upstream unloading valve 23 takes the unloading position 23y by the pressure of the upstream parallel line 22, and the pressure oil reaching the upstream unloading valve 23 flows through the downstream series line 41 of the downstream hydraulic circuit 40 and the bypass lines 50a and 55a of the downstream switching valves 50 and 55 to the tank line 6.
(case where the upstream side switching valve 30 is in the operating position)
Next, a case will be described in which the upstream-side switching valve 30 is switched to the operating position in a state in which the respective switching valves 30, 35, 50, and 55 are in the neutral positions 30x, 35x, 50x, and 55 x. When the upstream switching valve 30 is switched to the operating position, the upstream parallel line 21 of the upstream hydraulic circuit 20 is blocked, and therefore pressure oil is not supplied to the downstream parallel line 42 of the downstream hydraulic circuit 40.
The pressure oil of the upstream side parallel line 22 of the upstream side hydraulic circuit 20 reaches the pressure compensation valve 31 through the actuator line 30b of the upstream side switching valve 30. The pressure compensation valve 31 assumes an open position under the effect of the pressure of the actuator line 30b on the upstream side of the pressure compensation valve 31. The pressure oil that has passed through the pressure compensating valve 31 is supplied to the 1 st actuator 11 via the load holding check valve 33.
Further, the pressure oil of the actuator line 30b is supplied to the upstream side highest pressure detection line 24 via the highest pressure detection check valve 32. The pressure of the upstream side highest pressure detection line 24 acts in the direction of the closed position at the upstream side unloading valve 23 together with the spring 23 a. Therefore, the pressure of the upstream parallel line 22 connected to the upstream side port of the upstream unloading valve 23 rises to a pressure obtained by adding the pressure from the upstream highest pressure detection line 24 and the pressure from the spring 23 a.
(case where the upstream side switching valve 35 is in the operating position)
When the switching valves 30, 50, and 55 are in the neutral positions 35x, 50x, and 55x and the upstream-side switching valve 35 is in the operating position, the pressure oil is not supplied to the downstream-side parallel line 42 of the downstream-side hydraulic circuit 40, as in the case where the upstream-side switching valve 30 is in the operating position. Further, the pressure oil of the upstream side parallel line 22 is supplied to the 2 nd actuator 12 via the pressure compensating valve 36 and the load holding check valve 38. The pressure of the upstream side parallel line 22 rises to a pressure obtained by adding the pressure from the upstream side highest pressure detection line 24 and the pressure from the spring 23 a.
(case where the upstream side switching valves 30, 35 are in the operating positions)
Next, a case where both the upstream switching valves 30 and 35 are in the operating positions will be described. In this case, since the upstream side series line 21 of the upstream side hydraulic circuit 20 is blocked, the pressure oil is not supplied to the downstream side parallel line 42 of the downstream side hydraulic circuit 40. The pressure oil in the upstream parallel line 22 is supplied to the actuators 11 and 12 via the actuator lines 30b and 35b, the pressure compensating valves 31 and 36, and the load holding check valves 33 and 38.
The pressure oil in the actuator lines 30b, 35b is supplied to the upstream side maximum pressure detection line 24 via the maximum pressure detection check valves 32, 37, respectively. In this case, the higher pressure in the 1 st actuator 11 and the 2 nd actuator 12 acts on the upstream side highest pressure detection line 24. The pressure of the upstream side parallel line 22 rises to a pressure obtained by adding the pressure from the upstream side highest pressure detection line 24 and the pressure from the spring 23 a. Further, the pressure of the upstream side highest pressure detection line 24 acts on the pressure compensation valves 31, 36 in the direction of the closed position. Therefore, for example, when the pressure of the 1 st actuator 11 is higher than the pressure of the 2 nd actuator 12, the pressure of the 1 st actuator 11 acts in the direction of the closed position as the upstream side highest pressure detection line 24 at the pressure compensation valve 36. As a result, the pressure of the actuator line 35b increases at the pressure compensating valve 36. This makes the pressure of the 1 st actuator 11 and the pressure of the 2 nd actuator 12 equal to each other, and the pressure oil can be equally branched to the 1 st actuator 11 and the 2 nd actuator 12.
As described above, according to the present embodiment, as in the case of the conventional load sensing hydraulic control valve, the pressure oil can be supplied in accordance with the opening degree of each of the upstream switching valves 30 and 35 while adjusting the load of each of the actuators 11 and 12 connected to the upstream hydraulic circuit 20.
(case where the downstream side switching valve 50 is in the operating position)
Next, a case will be described in which the upstream switching valves 30 and 35 of the upstream hydraulic circuit 20 and the downstream switching valve 55 of the downstream hydraulic circuit 40 are in the neutral position, and the downstream switching valve 50 of the downstream hydraulic circuit 40 is in the operating position. In this case, since the downstream side series line 41 of the downstream side hydraulic circuit 40 is blocked, the pressure oil does not flow from the upstream side parallel line 22 of the upstream side hydraulic circuit 20 to the downstream side series line 41.
On the other hand, the pressure oil supplied from the hydraulic pump 2 and the high-pressure line 3 to the upstream series line 21 of the upstream hydraulic circuit 20 is passed through the bypass lines 30a and 35a of the upstream switching valves 30 and 35 to the downstream parallel line 42 of the downstream hydraulic circuit 40. The pressure oil of the downstream side parallel line 42 reaches the pressure compensating valve 51 through the actuator line 50b of the downstream side switching valve 50. The pressure compensation valve 51 assumes an open position under the action of the pressure of the actuator line 50b on the upstream side of the pressure compensation valve 51. The pressure oil that has passed through the pressure compensating valve 51 is supplied to the 3 rd actuator 13 via the load holding check valve 53.
The pressure oil in the actuator line 50b is supplied to the downstream side maximum pressure detection line 44 via the maximum pressure detection check valve 52. The pressure of the downstream side highest pressure detection line 44 acts in the direction of the closed position at the downstream side unloading valve 43 together with the spring 43 a. Therefore, the pressure of the downstream side parallel line 42 connected to the upstream side port of the downstream side unloading valve 43 rises to a pressure obtained by adding the pressure from the downstream side highest pressure detection line 44 and the pressure from the spring 43 a.
(case where the downstream side switching valve 55 is in the operating position)
When the upstream switching valves 30 and 35 of the upstream hydraulic circuit 20 and the downstream switching valve 50 of the downstream hydraulic circuit 40 are in the neutral position and the downstream switching valve 55 of the downstream hydraulic circuit 40 is in the actuated position, the pressure oil does not flow from the upstream parallel line 22 of the upstream hydraulic circuit 20 to the downstream series line 41, as in the case where the downstream switching valve 50 is in the actuated position. The pressurized oil in the upstream side series line 21 is supplied to the 4 th actuator 14 via the bypass lines 30a, 35a of the upstream side switching valves 30, 35, the downstream side parallel line 42 of the downstream side hydraulic circuit 40, the pressure compensating valve 56, and the load holding check valve 58. The pressure of the downstream side parallel line 42 rises to a pressure obtained by adding the pressure from the downstream side highest pressure detection line 44 and the pressure from the spring 43 a.
(case where the downstream side switching valves 50, 55 are in the operating positions)
Next, a case will be described in which the upstream switching valves 30 and 35 of the upstream hydraulic circuit 20 are in the neutral position and both the downstream switching valves 50 and 55 of the downstream hydraulic circuit 40 are in the operating positions. In this case, the pressure oil does not flow from the upstream side parallel line 22 of the upstream side hydraulic circuit 20 to the downstream side series line 41. The pressure oil supplied from the upstream side series line 21 to the downstream side parallel line 42 is supplied to the actuators 13, 14 via the actuator lines 50b, 55b, the pressure compensating valves 51, 56, and the load holding check valves 53, 58.
The pressure oil in the actuator lines 50b, 55b is supplied to the downstream side maximum pressure detection line 44 via the maximum pressure detection check valves 52, 57, respectively. In this case, the higher pressure in the 3 rd actuator 13 and the 4 th actuator 14 acts on the downstream side highest pressure detection line 44. The pressure of the downstream side parallel line 42 rises to a pressure obtained by adding the pressure from the downstream side highest pressure detection line 44 and the pressure from the spring 43 a. Further, the pressure of the downstream side highest pressure detection line 44 acts on the pressure compensation valves 51, 56 in the direction of the closed position. Therefore, for example, in the case where the pressure of the 3 rd actuator 13 is higher than the pressure of the 4 th actuator 14, the pressure of the 3 rd actuator 13 acts as the downstream side highest pressure detection line 44 toward the closed position at the pressure compensation valve 56. As a result, the pressure of the actuator line 55b increases at the pressure compensating valve 56. This makes the pressure of the 3 rd actuator 13 and the pressure of the 4 th actuator 14 equal to each other, and the pressure oil can be equally branched to the 3 rd actuator 13 and the 4 th actuator 14.
As described above, according to the present embodiment, as in the upstream hydraulic circuit 20, the load of each actuator 13, 14 connected to the downstream hydraulic circuit 40 can be adjusted in the downstream hydraulic circuit 40, and the pressure oil can be supplied according to the opening degree of each downstream switching valve 50, 55.
(case where the switching valves 30, 50 are in the working positions)
Next, a case where the upstream-side switching valve 30 of the upstream-side hydraulic circuit 20 and the downstream-side switching valve 50 of the downstream-side hydraulic circuit 40 are in the operating positions will be described. In this case, since the upstream side series line 21 of the upstream side hydraulic circuit 20 is blocked, the pressure oil is not supplied to the downstream side parallel line 42 of the downstream side hydraulic circuit 40. Therefore, the pressurized oil is not supplied to the 3 rd actuator 13 connected to the actuator line 50b of the downstream side switching valve 50. The pressure oil of the upstream side parallel line 22 is supplied to the 2 nd actuator 12 via the pressure compensating valve 36 and the load holding check valve 38.
As described above, according to the present embodiment, when the upstream-side switching valve of the upstream-side hydraulic circuit 20 and the downstream-side switching valve of the downstream-side hydraulic circuit 40 are simultaneously in the operating positions, the hydraulic circuit 1 can be operated so as to supply pressure oil only to the actuator connected to the upstream-side hydraulic circuit 20 and not to supply pressure oil to the actuator connected to the downstream-side hydraulic circuit 40. That is, a priority function of preferentially operating the actuator connected to the upstream side hydraulic circuit 20 can be realized. Further, it is possible to realize such a mechanical interlock function that intentionally prevents the actuator on the upstream side hydraulic circuit 20 side and the actuator on the downstream side hydraulic circuit 40 side from operating simultaneously.
According to the present embodiment, as described above, the load of each actuator can be adjusted in each of the upstream hydraulic circuit 20 and the downstream hydraulic circuit 40, and the pressure oil can be supplied according to the opening degree of each switching valve. In addition, a priority function and a mechanical interlock function can be realized. Therefore, a hydraulic apparatus excellent in safety and practicality can be provided.
Claims (7)
1. A hydraulic circuit in which, in a hydraulic circuit,
the hydraulic circuit includes:
an upstream side hydraulic circuit having an upstream side series line and an upstream side parallel line to which pressure oil is supplied from a hydraulic pump, an upstream side switching valve connected in series to the upstream side series line and connected in parallel to the upstream side parallel line, and an upstream side unloading valve connected to the upstream side parallel line; and
a downstream side hydraulic circuit having a downstream side series line connected to the upstream side parallel line via the upstream side unloading valve of the upstream side hydraulic circuit, a downstream side parallel line connected to the upstream side series line of the upstream side hydraulic circuit, a downstream side switching valve connected in series to the downstream side series line and connected in parallel to the downstream side parallel line, and a downstream side unloading valve located between the downstream side parallel line and a tank line.
2. The hydraulic circuit of claim 1,
the upstream-side switching valve has a bypass line connected to the upstream-side series line and an actuator line connected to the upstream-side parallel line and through which pressure oil supplied to the corresponding actuator passes.
3. The hydraulic circuit of claim 1,
the downstream-side switching valve includes a bypass line connected to the downstream-side series line and an actuator line connected to the downstream-side parallel line and through which pressure oil supplied to the corresponding actuator passes.
4. The hydraulic circuit of claim 2,
the upstream side hydraulic circuit has an upstream side highest pressure detection line connected in parallel to an actuator line of the upstream side switching valve via a check valve, the upstream side highest pressure detection line being connected to the upstream side unloading valve in such a manner as to act in a closed position direction at the upstream side unloading valve.
5. The hydraulic circuit of claim 4,
the upstream-side highest pressure detection line is connected to a pressure compensating valve via the check valve so as to act in a closed position direction on the pressure compensating valve connected in series with the actuator line of the upstream-side switching valve of the upstream-side hydraulic circuit.
6. The hydraulic circuit of claim 3,
the downstream side hydraulic circuit has a downstream side highest pressure detection line connected in parallel to an actuator line of the downstream side switching valve via a check valve, and the downstream side highest pressure detection line is connected to the downstream side unloading valve so as to act in a closed position direction at the downstream side unloading valve.
7. The hydraulic circuit of claim 6,
the downstream-side maximum pressure detection line is connected to a pressure compensation valve through the check valve so as to act in a closed position direction on the pressure compensation valve connected in series to the actuator line of the downstream-side switching valve of the downstream-side hydraulic circuit.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2019177677A JP7274391B2 (en) | 2019-09-27 | 2019-09-27 | hydraulic circuit |
| JP2019-177677 | 2019-09-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112576559A true CN112576559A (en) | 2021-03-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010879128.5A Pending CN112576559A (en) | 2019-09-27 | 2020-08-27 | Hydraulic circuit |
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| Country | Link |
|---|---|
| JP (1) | JP7274391B2 (en) |
| KR (1) | KR102817754B1 (en) |
| CN (1) | CN112576559A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0828504A (en) * | 1994-07-13 | 1996-02-02 | Hitachi Constr Mach Co Ltd | Hydraulic circuit of hydraulic excavator |
| JP2002068696A (en) * | 2000-08-25 | 2002-03-08 | Kawasaki Heavy Ind Ltd | Solenoid control valve for industrial vehicles |
| CN1693718A (en) * | 2004-03-10 | 2005-11-09 | 纳博特斯克株式会社 | Hydraulic circuits for construction machinery |
| JP2006233448A (en) * | 2005-02-22 | 2006-09-07 | Sumitomo (Shi) Construction Machinery Manufacturing Co Ltd | Alarm device of construction machine |
| JP2014206222A (en) * | 2013-04-12 | 2014-10-30 | 株式会社竹内製作所 | Hydraulic drive device and hydraulic drive method |
| CN208918947U (en) * | 2018-09-27 | 2019-05-31 | 厦门联帮匠心机械设备有限公司 | Multifunctional decompression separate system |
| US20190194910A1 (en) * | 2017-03-13 | 2019-06-27 | Hitachi Construction Machinery Tierra Co., Ltd. | Hydraulic Drive System for Electrically-Driven Hydraulic Work Machine |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3511425B2 (en) | 1995-09-18 | 2004-03-29 | 日立建機株式会社 | Hydraulic system |
| JPH11173304A (en) * | 1997-10-09 | 1999-06-29 | Kayaba Ind Co Ltd | Hydraulic control device |
| JP2001099105A (en) * | 1999-10-01 | 2001-04-10 | Kayaba Ind Co Ltd | Hydraulic control device |
| JP4960646B2 (en) | 2006-04-05 | 2012-06-27 | 東芝機械株式会社 | Load sensing hydraulic controller |
| EP2602491B1 (en) * | 2010-08-03 | 2021-03-31 | Kobelco Construction Machinery Co., Ltd. | Construction machine having hydraulic circuit |
| EP2977620B1 (en) * | 2013-03-22 | 2018-01-17 | Hitachi Construction Machinery Tierra Co., Ltd. | Hydraulic drive device of construction machine |
| DE102014208019B4 (en) * | 2014-04-29 | 2025-01-30 | Robert Bosch Gmbh | Hydraulic control arrangement for several actuators |
| JP6262676B2 (en) | 2015-02-06 | 2018-01-17 | 株式会社日立建機ティエラ | Hydraulic drive unit for construction machinery |
| JP2021031535A (en) * | 2019-08-20 | 2021-03-01 | 京セラドキュメントソリューションズ株式会社 | Ink black ink for sublimation transfer |
-
2019
- 2019-09-27 JP JP2019177677A patent/JP7274391B2/en active Active
-
2020
- 2020-08-24 KR KR1020200105933A patent/KR102817754B1/en active Active
- 2020-08-27 CN CN202010879128.5A patent/CN112576559A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0828504A (en) * | 1994-07-13 | 1996-02-02 | Hitachi Constr Mach Co Ltd | Hydraulic circuit of hydraulic excavator |
| JP2002068696A (en) * | 2000-08-25 | 2002-03-08 | Kawasaki Heavy Ind Ltd | Solenoid control valve for industrial vehicles |
| CN1693718A (en) * | 2004-03-10 | 2005-11-09 | 纳博特斯克株式会社 | Hydraulic circuits for construction machinery |
| JP2006233448A (en) * | 2005-02-22 | 2006-09-07 | Sumitomo (Shi) Construction Machinery Manufacturing Co Ltd | Alarm device of construction machine |
| JP2014206222A (en) * | 2013-04-12 | 2014-10-30 | 株式会社竹内製作所 | Hydraulic drive device and hydraulic drive method |
| US20190194910A1 (en) * | 2017-03-13 | 2019-06-27 | Hitachi Construction Machinery Tierra Co., Ltd. | Hydraulic Drive System for Electrically-Driven Hydraulic Work Machine |
| CN208918947U (en) * | 2018-09-27 | 2019-05-31 | 厦门联帮匠心机械设备有限公司 | Multifunctional decompression separate system |
Also Published As
| Publication number | Publication date |
|---|---|
| KR102817754B1 (en) | 2025-06-09 |
| JP7274391B2 (en) | 2023-05-16 |
| KR20210037526A (en) | 2021-04-06 |
| JP2021055716A (en) | 2021-04-08 |
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