Preferential valve and hydraulic system including the same

Abstract

The present invention relates to a first valve and a hydraulic system including the same. A hydraulic system according to an embodiment of the present invention comprises a main hydraulic pump that discharges hydraulic fluid, a plurality of driving devices that operate by receiving hydraulic fluid, a parallel path through which the hydraulic fluid discharged by the main hydraulic pump moves, a plurality of directional control valves each connected in parallel with the parallel path to control the supply of hydraulic fluid to the plurality of driving devices, and a first valve installed between any one selected of the plurality of directional control valves and the parallel path. When the pressure of the hydraulic fluid supplied through the parallel path decreases, the flow rate of the hydraulic fluid passing through the first valve increases.

Description

Technology Field

[0001] The present invention relates to construction machinery, and more specifically, to a hydraulic system used in construction machinery. Background Technology

[0002] Generally, hydraulic systems transmit power through hydraulic fluid discharged by a hydraulic pump to operate various drive devices. Such hydraulic systems are widely used in construction machinery or industrial vehicles. For example, hydraulic systems used in construction machinery drive drive devices such as a drive motor used for driving, a swing motor used for the swing of the upper slewing body, and boom cylinders, arm cylinders, bucket cylinders, and optional cylinders used in the working device, through hydraulic fluid discharged from a hydraulic pump operated by an engine.

[0003] And these drive units are driven by hydraulic fluid discharged from a variable displacement hydraulic pump driven by an engine or an electric motor, and the hydraulic fluid discharged from the hydraulic pump is distributed to each drive unit by a plurality of directional control valves.

[0004] As such, a hydraulic pump and multiple drive units are connected through multiple directional control valves. However, when two or more drive units are driven in combination, the pressure of the hydraulic fluid supplied to each drive unit cannot be maintained at a constant level. Since each drive unit requires a different load, if the pressure of one drive unit decreases during combined operation, the hydraulic fluid with lower pressure cannot move to the drive unit with higher pressure and is diverted to the drive unit with lower pressure, resulting in a problem where the drive unit requiring a high load is difficult to operate. The problem to be solved

[0005] An embodiment of the present invention can provide a priority valve capable of controlling the flow rate of the working fluid according to pressure fluctuations in a parallel flow path supplying the working fluid.

[0006] In addition, according to an embodiment of the present invention, a hydraulic system can be provided that maintains a constant flow rate ratio of the hydraulic fluid supplied to each driving device when a plurality of driving devices are driven in combination. means of solving the problem

[0007] According to an embodiment of the present invention, first, the valve comprises a parallel passage for supplying operating fluid, a transmission passage for delivering the operating fluid supplied by the parallel passage, and a poppet receiving portion provided at the confluence point of the parallel passage and the transmission passage, wherein the parallel passage is installed in the poppet receiving portion of the housing to be openable and closable; a valve body coupled to the housing; a main piston installed inside the valve body to be reciprocally movable in the direction of the poppet, with one end selectively pressurizing the poppet; a pilot piston installed inside the valve body to be reciprocally movable in the direction of the poppet, with one end selectively pressurizing the main piston; a pilot port coupled to the valve body to transmit pilot pressure to the pilot piston; and a connecting passage connecting the parallel passage to the interior of the valve body. Additionally, an annular chamber is formed inside the valve body to pressurize the pilot piston toward the main piston, and the connecting passage connects the parallel passage and the annular chamber. When the pressure in the parallel passage is the supply reference pressure and the pilot pressure transmitted through the pilot port is the pilot reference pressure, the force acting in the direction of opening the poppet and the force acting in the direction of closing the poppet are in equilibrium, and the area of ​​one end of the poppet where the pressure in the parallel passage acts is smaller than the hydraulic area of ​​the annular chamber where the pressure in the parallel passage acts through the connecting passage.

[0008] If the pressure in the parallel channel decreases below the supply reference pressure, the force in the direction of opening the poppet increases, and if the pressure in the parallel channel increases above the supply reference pressure, the force in the direction of closing the poppet may increase.

[0009] The poppet, the main piston, and the pilot piston may be formed such that the sum of the first force due to the pressure in the parallel channel applied to the poppet, the second force due to the pressure in the transmission channel applied to the poppet in the direction in which the poppet opens, and the third force due to the pressure in the transmission channel applied to the main piston is in equilibrium with the sum of the fourth force due to the pressure in the transmission channel applied to the poppet in the direction in which the poppet closes, the fifth force due to the pressure in the parallel channel applied to the pilot piston through the connecting channel, and the sixth force due to the pilot pressure applied to the pilot piston.

[0010] The first force is the product of the first hydraulic pressure area, which is the area of ​​one end of the poppet blocking the parallel flow path, and the pressure within the parallel flow path; the second force is the product of the second hydraulic pressure area, which is the pressure within the transmission flow path acting on the poppet in the direction in which the poppet opens, and the pressure within the transmission flow path; the third force is the product of the third hydraulic pressure area, which is the total area of ​​the main piston acting on the poppet, and the pressure within the transmission flow path; the fourth force is the product of the fourth hydraulic pressure area, which is the pressure within the transmission flow path acting on the poppet in the direction in which the poppet closes, and the pressure within the transmission flow path; the fifth force is the product of the fifth hydraulic pressure area, which is the hydraulic pressure area of ​​the annular chamber, and the pressure within the parallel flow path; and the sixth force may be the product of the sixth hydraulic pressure area, which is the hydraulic pressure area of ​​the pilot piston where the pilot pressure acts, and the pilot pressure.

[0011] The above-mentioned fifth pressure area can be formed to be larger than the above-mentioned first pressure area.

[0012] In addition, an orifice may be formed in the above-mentioned connecting channel.

[0013] A hollow internal space is formed in the above-mentioned poppet, and a through hole connecting the transmission channel and the internal space may be formed on the side of the above-mentioned poppet.

[0014] And the pressure within the above-mentioned transmission path can act in the internal space of the poppet through the above-mentioned passage of the poppet.

[0015] One end of the main piston can be inserted into the internal space of the poppet to pressurize the poppet.

[0016] The above-described priority valve may further include a poppet spring that elastically supports the poppet in the direction in which the poppet closes, and a pilot spring that elastically supports the pilot piston in the direction in which the pilot piston moves away from the poppet.

[0017] The force exerted by the above-mentioned poppet spring and the force exerted by the above-mentioned pilot spring can cancel each other out.

[0018] In addition, according to an embodiment of the present invention, the hydraulic system comprises a main hydraulic pump that discharges hydraulic fluid, a plurality of drive devices that operate by receiving hydraulic fluid, a parallel flow path through which the hydraulic fluid discharged by the main hydraulic pump travels, a plurality of directional control valves each connected in parallel with the parallel flow path to control the supply of hydraulic fluid to the plurality of drive devices, and a priority valve installed between any one selected of the plurality of directional control valves and the parallel flow path. Here, the priority valve comprises a parallel passage and a transfer passage for transferring the operating fluid supplied by the parallel passage to any one selected of the plurality of directional control valves, and a poppet installed in the poppet receiving portion of a housing provided at the confluence point of the parallel passage and the transfer passage so as to open and close the parallel passage; a valve body coupled to the housing; a main piston installed inside the valve body so as to be reciprocally movable in the direction of the poppet, with one end selectively pressurizing the poppet; a pilot piston installed inside the valve body so as to be reciprocally movable in the direction of the poppet, with one end selectively pressurizing the main piston; a pilot port coupled to the valve body to transmit pilot pressure to the pilot piston; and a connecting passage connecting the parallel passage to the interior of the valve body.And an annular chamber is formed inside the valve body to pressurize the pilot piston toward the main piston, and the connecting passage connects the parallel passage and the annular chamber, and when the pressure in the parallel passage is the supply reference pressure and the pilot pressure transmitted through the pilot port is the pilot reference pressure, the force acting in the direction of opening the poppet and the force acting in the direction of closing the poppet are in equilibrium, and the area of ​​one end of the poppet where the pressure in the parallel passage acts is formed to be smaller than the hydraulic area of ​​the annular chamber where the pressure in the parallel passage acts through the connecting passage.

[0019] The above supply reference pressure may be the pressure within the parallel flow path when the operating fluid discharged by the main hydraulic pump is supplied to any one of the plurality of driving devices.

[0020] When two or more driving devices, including the driving device that receives operating fluid from the directional control valve connected to the priority valve among the plurality of driving devices above, operate simultaneously, the pressure of the operating fluid supplied through the parallel path is reduced, and as the pressure within the parallel path decreases below the supply reference pressure, the force in the direction in which the poppet opens increases, and the supply of operating fluid to the directional control valve connected to the priority valve can be prioritized over other directional control valves.

[0021] The plurality of drive devices include a boom cylinder, an arm cylinder, a slewing motor, and an optional cylinder, and the direction change valve controlling the supply of hydraulic fluid to the optional cylinder can receive hydraulic fluid through the priority valve. Effects of the invention

[0022] According to an embodiment of the present invention, first, the valve can control the flow rate of the working fluid according to pressure fluctuations in the parallel flow path supplying the working fluid.

[0023] In addition, according to an embodiment of the present invention, the hydraulic system can maintain a constant flow rate ratio of the hydraulic fluid supplied to each driving device when a plurality of driving devices are driven in combination. Brief explanation of the drawing

[0024] FIG. 1 is a cross-sectional view of a priority valve according to a first embodiment of the present invention. Figure 2 shows the force acting on the poppet of Figure 1. Figures 3 and 4 show the operating states of the priority valve of Figure 1. Figure 5 shows a directional switching valve connected to the priority valve of Figure 1. FIG. 6 shows a hydraulic system according to a second embodiment of the present invention. FIG. 7 shows a hydraulic system according to a third embodiment of the present invention. FIG. 8 shows a hydraulic system according to a fourth embodiment of the present invention. Specific details for implementing the invention

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0026] In addition, in various embodiments, components having the same configuration are described representatively in the first embodiment using the same reference numerals, and in other embodiments, only configurations different from the first embodiment are described.

[0027] It should be noted that the drawings are schematic and not drawn to scale. The relative dimensions and proportions of parts in the drawings are exaggerated or reduced in size for clarity and convenience in the drawings, and any dimensions are merely illustrative and not limiting. Additionally, the same reference numerals are used to denote similar features for the same structure, element, or part appearing in two or more drawings.

[0028] The embodiments of the present invention specifically illustrate ideal embodiments of the present invention. As a result, various variations of the illustration are expected. Accordingly, the embodiments are not limited to the specific form of the illustrated area and include, for example, variations in form resulting from manufacturing.

[0029] Furthermore, all technical and scientific terms used in this specification, unless otherwise defined, have the meaning generally understood by those skilled in the art to which the present invention pertains. All terms used in this specification are selected for the purpose of further clarifying the present invention and are not selected to limit the scope of rights according to the present invention.

[0030] Additionally, expressions used in this specification, such as 'comprising,' 'having,' 'having,' etc., should be understood as open-ended terms implying the possibility of including other embodiments, unless otherwise stated in the phrase or sentence containing such expressions.

[0031] Additionally, singular expressions described in this specification may include the meaning of the plural form unless otherwise stated, and this applies likewise to singular expressions described in the claims.

[0032] Additionally, expressions such as 'first', 'second', etc. used in this specification are used to distinguish multiple components from one another and do not limit the order or importance of said components.

[0033] Hereinafter, a first valve (101) according to a first embodiment of the present invention will be described with reference to FIGS. 1 and FIGS. 2.

[0034] The priority valve (101) according to the first embodiment of the present invention is a load-sensitive variable flow control valve. For example, as shown in FIG. 6, the priority valve (101) can be used to control the flow rate of the supplied hydraulic fluid in order to adjust the supply order of the hydraulic fluid according to pressure fluctuations of the hydraulic fluid supplied from the hydraulic system (201). Specifically, the priority valve (101) can be connected to any one of a selected directional control valve (200) that controls the supply of hydraulic fluid to a plurality of driving devices (800) and can control the flow rate of the hydraulic fluid supplied to the directional control valve (200).

[0035] As illustrated in FIG. 1, the first valve (101) according to the first embodiment of the present invention includes a poppet (110), a valve body (150), a main piston (120), a pilot piston (130), a pilot port (140), and a connecting path (615).

[0036] Additionally, the first valve (101) according to the first embodiment of the present invention may further include a poppet spring (181) and a pilot spring (183).

[0037] A poppet (110) may be installed in a poppet receiving portion (421) of a housing (420) to open and close a parallel flow path (610). Here, the housing (420) may include a parallel flow path (610) for supplying hydraulic fluid, a transmission flow path (620) for transmitting the hydraulic fluid supplied by the parallel flow path (610), and a poppet receiving portion (421) provided at the confluence point of the parallel flow path (610) and the transmission flow path (620). That is, the poppet (110) opens and closes the parallel flow path (610) while moving in a straight reciprocating motion in the poppet receiving portion (421). For example, when the poppet (110) moves forward, the parallel flow path (610) is closed, and when the poppet (110) moves backward, the parallel flow path (610) is opened.

[0038] Specifically, a hollow internal space (115) is formed in the poppet (110), and a through hole (116) connecting the transmission channel (620) and the internal space (115) may be formed on the side of the poppet (110). And pressure within the transmission channel (620) can act in the internal space (115) of the poppet (110) through the through hole (116) of the poppet (110).

[0039] The valve body (150) can be coupled to the housing (420). At this time, the valve body (150) and the housing (420) can be coupled in a sealed manner. The valve body (150) can accommodate the main piston (120) and the pilot piston (130), which will be described later, in a linear reciprocating manner. Here, the main piston (120) and the pilot piston (130) may have different diameters, and the area accommodating the main piston (120) and the area accommodating the pilot piston (130) may have different inner diameters and form a step. By utilizing this step, the poppet spring (181) and the pilot spring (183), which will be described later, can be installed.

[0040] The main piston (120) is installed inside the valve body (150) to move in a straight reciprocating motion toward the poppet (110), and one end can selectively pressurize the poppet (110). That is, when the main piston (120) advances, it pressurizes the poppet (110), and when the main piston (120) retracts, the pressurization of the poppet (110) can be released. At this time, one end of the main piston (120) can be inserted into the internal space (115) of the poppet (110) to pressurize the poppet (110).

[0041] The pilot piston (130) is installed to move in a straight reciprocating motion in the direction of the poppet (110) inside the valve body (150), and one end can selectively pressurize the main piston (120). That is, when the pilot piston (130) advances, it pressurizes the main piston (120), and when the pilot piston (130) retracts, the pressurization on the main piston (120) can be released. At this time, an annular chamber (153) is formed inside the valve body (150) to pressurize the pilot piston (130) in the direction of the main piston (120), and a connecting passage (615) can connect the parallel passage (610) and the annular chamber (153). That is, the connecting passage (615) can connect the parallel passage (610) to the inside of the valve body (150) and transmit the pressure inside the parallel passage (610) to the annular chamber (153). Accordingly, the pilot piston (130) pressurizes the main piston (120) by the pressure within the parallel flow path (610) delivered to the annular chamber (153).

[0042] Meanwhile, an orifice (617) may be formed in the connecting channel (615). Accordingly, the rapid transmission of pressure within the parallel channel (610) to the annular chamber (150) through the connecting channel (615) can be mitigated.

[0043] The pilot port (140) is coupled to the valve body (150) and can transmit pilot pressure (Peppr) to the pilot piston (130). That is, the pilot port (140) serves to guide pilot pressure (Peppr) to the other end of the pilot piston (130) opposite to the end facing the main piston (120).

[0044] With this structure, the poppet (110) opens or closes due to variations in the force applied to the poppet (110).

[0045] That is, when the pressure in the parallel channel (610) is the supply reference pressure and the pilot pressure transmitted through the pilot port (140) is the pilot reference pressure, the force acting on the poppet (110) in the direction in which the poppet (110) opens and the force acting on the poppet (110) in the direction in which the poppet (110) closes are in equilibrium.

[0046] In the first embodiment of the present invention, in particular, the area (A1) of one end of the poppet (110) where pressure acts within the parallel channel (610) is formed to be smaller than the hydraulic area (A5) of the annular chamber (153) where pressure acts through the connecting channel (615) within the parallel channel (610). Here, the supply reference pressure may be the pressure within the parallel channel (610) when the working fluid discharged by the main hydraulic pump (310) shown in FIG. 6 is supplied to any one of the plurality of driving devices (800). Additionally, the pilot reference pressure may be set as needed and may be zero, for example.

[0047] Accordingly, if the pressure in the parallel channel (610) decreases below the supply reference pressure, the force in the direction of opening the poppet (110) increases, and if the pressure in the parallel channel (610) increases above the supply reference pressure, the force in the direction of closing the poppet (110) may increase.

[0048] Hereinafter, the force acting on the poppet (110) will be described in detail with reference to FIG. 2.

[0049] As illustrated in FIG. 2, there is a first force (F1) due to pressure within the parallel channel applied to the poppet (110), a second force (F2) due to pressure within the transmission channel (620) applied to the poppet (110) in the direction in which the poppet (110) opens, a third force (F3) due to pressure within the transmission channel (620) applied to the main piston (120), a fourth force (F4) due to pressure within the transmission channel (620) applied to the poppet (110) in the direction in which the poppet (110) closes, a fifth force (F5) due to pressure within the parallel channel applied to the pilot piston (130) through the connecting channel (615), and a sixth force (F6) due to pilot pressure applied to the pilot piston (130).

[0050] And the poppet (110), main piston (120), and pilot piston (130) are formed such that the sum of the first force (F1), the second force (F2), and the third force (F3) is in equilibrium with the sum of the fourth force (F4), the fifth force (F5), and the sixth force (F6).

[0051] Specifically, the first force (F1) is the product of the first hydraulic pressure area (A1), which is the area of ​​one end of the poppet (110) blocking the parallel flow path (610), and the pressure (Pp) inside the parallel flow path (610).

[0052] The second force (F2) is the product of the pressure (Pa) within the transmission channel (620) and the second hydraulic pressure area (A2) acting on the poppet (110) in the direction in which the poppet (110) opens.

[0053] The third force (F3) is the product of the third hydraulic area (A3), which is the total area that the main piston (120) acts upon with the poppet (110), and the pressure (Pa) within the transmission path (620).

[0054] The fourth force (F4) is the product of the pressure (Pa) in the transmission channel (620) and the fourth hydraulic pressure area (A4) acting on the poppet (110) in the direction in which the pressure (Pa) in the transmission channel (620) closes.

[0055] The fifth force (F5) is the product of the fifth hydraulic area (A5), which is the hydraulic area of ​​the annular chamber (153), and the pressure (Pp) in the parallel flow path (610).

[0056] The sixth force (F6) is the product of the sixth hydraulic area (A6), which is the hydraulic area of ​​the pilot piston (130) on which the pilot pressure (Peppr) acts, and the pilot pressure (Peppr).

[0057] In particular, in the first embodiment of the present invention, the fifth hydraulic area (A5) is formed to be larger than the first hydraulic area (A1). Accordingly, as previously explained, this means that the area (A1) of one end of the poppet (110) where the pressure (Pp) within the parallel channel (610) acts is formed to be smaller than the hydraulic area (A5) of the annular chamber (153) where the pressure (Pp) within the parallel channel (610) acts through the connecting channel (620).

[0058] As mentioned above, the force acting on the poppet (110) can be summarized in Equation 1 below.

[0059]

[0060] Here, Pp is the pressure in the parallel channel (610), Pa is the pressure in the transmission channel (620), A1 is the first hydraulic pressure area, A2 is the second hydraulic pressure area, A3 is the third hydraulic pressure area, A4 is the fourth hydraulic pressure area, and A5 is the fifth hydraulic pressure area. At this time, the pilot pressure (Peppr) acting on the sixth hydraulic pressure area (A6) is 0.

[0061] For example, the first hydraulic pressure area (A1) is 8mm 2 and the second hydraulic pressure area (A2) is 10mm 2 and the third hydraulic pressure area (A3) is 6mm 2 and the fourth hydraulic pressure area (A4) is 6mm 2 and the 5th hydraulic pressure area (A5) is 10mm 2In this case, if the pressure (Pp) in the parallel channel (610) is 40 bar and the pressure (Pa) in the transmission channel (620) is 40 bar, the force acting on the poppet (110) in the direction in which the poppet (110) opens is 800 bar / mm 2 This is the case, and the force acting on the poppet (110) in the direction in which the poppet (110) closes is also 800 bar / mm 2 As a result, forces in both directions are balanced as shown in Fig. 3. At this time, the supply reference pressure can be 40 bar and the pilot reference pressure can be 0 bar.

[0062] In this state, if the pressure (Pp) in the parallel channel (610) decreases from 40 bar to 30 bar due to load fluctuation, the force acting on the poppet (110) in the direction in which the poppet (110) opens is 720 bar / mm 2 The force acting on the poppet (110) in the direction in which it changes and the poppet (110) closes is 700 bar / mm 2 As it changes, as shown in FIG. 4, the poppet (110) opens more easily, and a larger flow of hydraulic fluid can be supplied to the driving device (800) through the directional control valve (200) connected to the valve (101).

[0063] Conversely, if the pressure (Pp) in the parallel path (610) increases from 40 bar to 50 bar due to load fluctuation, the poppet (110) becomes difficult to open, and a smaller flow of working fluid is supplied to the driving device (800) through the directional control valve (200) connected to the valve (101).

[0064] In this way, first, the valve (101) can control the flow rate of the hydraulic fluid supplied to the directional control valve (200) and the driving device (800) according to the pressure fluctuation of the parallel flow path (610) that supplies the hydraulic fluid.

[0065] The poppet spring (181) can elastically support the poppet (110) in the direction in which the poppet (110) closes.

[0066] The pilot spring (183) can elastically support the pilot piston (130) in a direction in which the pilot piston (130) moves away from the poppet (110).

[0067] And the force exerted by the poppet spring (181) and the force exerted by the pilot spring (183) cancel each other out.

[0068] For example, the force acting on the poppet (110) corresponds to the difference between the force of the poppet spring (181) elastically supporting the poppet (110) and the force of the pilot spring (183) supporting the pilot piston (130). That is, since the poppet spring (181) and the pilot spring (183) act in opposite directions, if the force of the poppet spring (181) and the force of the pilot spring (183) cancel each other out, the force of the poppet spring (181) and the pilot spring (183) acting on the poppet (110) becomes smaller.

[0069] In particular, the force of the poppet spring (181) and the force of the pilot spring (183) are negligible compared to the force (Pp) due to pressure in the parallel path (610) or the force (Pa) due to pressure in the transmission path (620), and thus do not significantly affect the operation of the poppet (110). Therefore, in the first embodiment of the present invention, the force of the poppet spring (181) and the force of the pilot spring (183) are to be ignored. The poppet spring (181) and the pilot spring (183) are each significant in positioning the poppet (110) and the pilot piston (130) in the correct position in the absence of external force.

[0070] With such a configuration, the priority valve (101) according to the first embodiment of the present invention can control the flow rate of the working fluid according to the pressure fluctuation of the parallel flow path (610) that supplies the working fluid.

[0071] Specifically, the flow rate of the working fluid passing through the poppet (110) can be increased when the pressure of the parallel channel (610) decreases, and the flow rate of the working fluid passing through the poppet (110) can be adjusted to decrease when the pressure of the parallel channel (610) increases.

[0072] Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 5 and FIGS. 6.

[0073] FIG. 5 shows a directional control valve (200) combined with a first valve (101), and FIG. 6 shows a hydraulic system (201) to which the first valve (101) is applied.

[0074] As illustrated in FIGS. 5 and 6, a hydraulic system (201) according to a second embodiment of the present invention includes a main hydraulic pump (310), a plurality of driving devices (800), a parallel flow path (610), a plurality of directional switching valves (200), and a priority valve (101). Here, the priority valve (101) is the priority valve (101) described above in the first embodiment.

[0075] The main hydraulic pump (310) can discharge hydraulic fluid. The main hydraulic pump (310) can be connected to a power device, such as an engine or a motor, and driven by rotational power provided by the power device. Additionally, the main hydraulic pump (310) may be a swashplate type variable displacement type. That is, the main hydraulic pump (310) can adjust the discharge flow rate by adjusting the angle of the swashplate.

[0076] A plurality of drive units (800) can operate by receiving hydraulic fluid discharged by the main hydraulic pump (310). For example, if the hydraulic system (101) is used in a construction machine such as an excavator, the plurality of drive units (800) may include a drive motor (810) used for driving, a swing motor (820) (shown in FIG. 8) used for swinging the upper slewing body, a boom cylinder (830), an arm cylinder (840) (shown in FIG. 8) used for the working device, a bucket cylinder (not shown), and an optional cylinder (870), etc.

[0077] FIG. 6 illustrates, for example, a driving motor (810), a boom cylinder (830), and an optional cylinder (870) as a plurality of driving devices (800).

[0078] The parallel flow path (610) can move the hydraulic fluid discharged by the main hydraulic pump (310). Additionally, the parallel flow path (610) can be formed to be long in a direction that intersects the direction in which the plurality of directional control valves (200), which will be described later, reciprocate. Here, the plurality of directional control valves (200) reciprocate in the longitudinal direction. For example, if the plurality of directional control valves (200) are arranged to have a length in the transverse direction, the parallel flow path (610) can be formed to have a length in the vertical direction. Furthermore, the parallel flow path (610) can receive hydraulic fluid from the main hydraulic pump (310) and distribute it to each of the plurality of directional control valves (200).

[0079] A plurality of directional control valves (200) are each connected in parallel with a parallel flow path (610) to control the supply of hydraulic fluid to a plurality of driving devices (800). A plurality of directional control valves (200) can each be installed to be reciprocally movable within a housing (420). The direction of movement of the hydraulic fluid can be controlled according to the positional movement of the plurality of directional control valves (200). That is, the plurality of directional control valves (200) can control whether the plurality of driving devices (800) operate and the direction of operation.

[0080] Additionally, a plurality of directional control valves (200) may be provided in proportion to the number of driving devices (800). That is, the number of directional control valves (200) may be determined according to the number of driving devices (800) that control the supply of hydraulic fluid.

[0081] A plurality of first supply channels (681) and a plurality of second supply channels (682) each connect a plurality of directional switching valves (200) and a plurality of driving devices (800).

[0082] Specifically, a plurality of first supply channels (681) can each connect one side of a plurality of directional switching valves (200) to one side of a plurality of driving devices (800).

[0083] A plurality of second supply channels (682) can each connect the other side of a plurality of directional switching valves (200) to the other side of a plurality of driving devices (800).

[0084] In addition, the hydraulic fluid that has moved to the multiple direction change valves (200) through the multiple transmission paths (620) according to the positional movement of the multiple direction change valves (510) can be supplied to the multiple driving devices (800) through the multiple first supply paths (681) or the multiple second supply paths (682). That is, the multiple direction change valves (200) not only distribute the hydraulic fluid discharged by the main hydraulic pump (310) to the various driving devices (800), but can also change the direction of operation of each driving device (800). Accordingly, the various driving devices (800) can perform extension and contraction, forward and backward, or left turn and right turn operations.

[0085] Meanwhile, as described above, the housing (420) may be formed with a plurality of transfer passages (620) for each transferring the operating fluid supplied by the parallel passage (610) to one of the selected directional control valves (200), and a poppet receiving portion (421) provided at the confluence point of the parallel passage (610) and the transfer passages (620). Additionally, a portion of the first supply passage (681) and a portion of the second supply passage (682) may also be formed in the housing (420).

[0086] First, the valve (101) may be installed between a selected one of the plurality of directional control valves (200) and a parallel flow path (610). Specifically, the priority valve (101) is the same as the priority valve (101) described in the first embodiment above. That is, the priority valve (101) is a load-sensitive variable flow control valve.

[0087] For example, when a plurality of drive units (800) include a driving motor (810), an optional cylinder (870), and a boom cylinder (830), the first valve (101) may be connected to a directional valve (270) for supplying hydraulic fluid to the optional cylinder (870) among the plurality of directional valves (800).

[0088] In FIG. 6, reference numeral 210 is a directional control valve for supplying hydraulic fluid to a driving motor (810), and reference numeral 230 is a directional control valve for supplying hydraulic fluid to a boom cylinder (830).

[0089] That is, the first valve (101) can be installed between the directional valve (270) and the parallel flow path (610) for supplying working fluid to the optional cylinder (870). And the first valve (101) can be connected to the directional valve (270) through the transmission flow path (620).

[0090] At this time, when the boom cylinder (830) and the option cylinder (870) are driven in combination and the pressure supplied through the parallel path (610), that is, the pressure (Pp) within the parallel path (610), is lowered, since the required loads of the boom cylinder (830) and the option cylinder (870) are different, when the pressure of one driving device (800) is lowered during combined driving, the low-pressure hydraulic fluid cannot move to the high-pressure driving device (800) and is concentrated in the low-pressure driving device (800), making it difficult for the driving device (800) requiring a high load to operate. At this time, the valve (101) first maintains a constant flow rate ratio of the hydraulic fluid supplied to the boom cylinder (830) and the option cylinder (870), thereby preventing the phenomenon in which some driving devices (800) do not operate normally.

[0091] With such a configuration, the hydraulic system (201) according to the second embodiment of the present invention can maintain a constant flow rate ratio of the hydraulic fluid supplied to each driving device (800) when a plurality of driving devices (800) are driven in combination.

[0092] Hereinafter, a third embodiment of the present invention will be described with reference to FIG. 7.

[0093] As illustrated in FIG. 7, in the hydraulic system (202) according to the third embodiment of the present invention, a pilot pressure (Peppr) is added to the force acting on the poppet (110) (illustrated in FIG. 1) of the valve (101). In the first embodiment described above, the pilot pressure (Peppr) acting on the valve (101) was zero.

[0094] In the third embodiment of the present invention, the operation of the first valve (101) can be artificially controlled by adding a pilot pressure (Peppr) to the first valve (101). At this time, the pilot pressure (Peppr) acts in the direction in which the poppet (110) closes, as previously shown in FIG. 2.

[0095] Thus, except for the fact that a pilot pressure (Peppr) is added to the valve (101), the hydraulic system (202) according to the third embodiment of the present invention is identical to the hydraulic system (201) according to the second embodiment described above.

[0096] Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG. 8.

[0097] As illustrated in FIG. 8, the hydraulic system (203) according to the fourth embodiment of the present invention may have three of the plurality of driving devices (800) driven in combination.

[0098] For example, when a plurality of drive units (800) include a driving motor (810), a turning motor (820), an arm cylinder (840), and an optional cylinder (870), the first valve (101) may be connected to a direction change valve (270) for supplying hydraulic fluid to the optional cylinder (870) among a plurality of direction change valves (200).

[0099] In FIG. 8, reference numeral 210 is a directional control valve for supplying hydraulic fluid to a driving motor (810), reference numeral 220 is a directional control valve for supplying hydraulic fluid to a turning motor (820), and reference numeral 240 is a directional control valve for supplying hydraulic fluid to an arm cylinder (830).

[0100] That is, the first valve (101) can be installed between the directional valve (270) and the parallel flow path (610) for supplying working fluid to the optional cylinder (870). And the first valve (101) can be connected to the directional valve (270) through the transmission flow path (620).

[0101] At this time, when the rotation motor (820), arm cylinder (830), and option cylinder (870) are driven in combination and the pressure supplied through the parallel path (610), i.e., the pressure (Pp) within the parallel path (610), decreases, the rotation motor (820), arm cylinder (840), and option cylinder (870) have different required loads. Therefore, when the pressure of one driving device (800) decreases during combined driving, the low-pressure hydraulic fluid cannot move to the driving device (800) with high pressure and is concentrated in the driving device (800) with low pressure, making it difficult for the driving device (800) requiring a high load to operate. At this time, the valve (101) first maintains a constant flow rate ratio of the hydraulic fluid supplied to the rotation motor (820), arm cylinder (840), and option cylinder (870), thereby preventing the phenomenon in which some driving devices (800) do not operate normally.

[0102] With this configuration, the hydraulic system (203) according to the fourth embodiment of the present invention can maintain a constant flow rate ratio of the hydraulic fluid supplied to each driving device (800) even when three driving devices (800) are driven in combination.

[0103] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art to which the present invention pertains will understand that the present invention may be implemented in other specific forms without changing its technical concept or essential features.

[0104] Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting, and the scope of the invention is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalents thereof should be interpreted as being included within the scope of the invention. Explanation of the symbols

[0105] 101: First, the valve 110: Poppet 115: Interior space 116: Passage hole 120: Main piston 130: Pilot Piston 140: Pilot Port 150: Valve body 153: Annular chamber 181: Poppet Spring 183: Pilot Spring 201, 202, 203: Hydraulic System 200, 210, 220, 230, 240, 270: Directional valves 310 Main Hydraulic Pump 420: Housing 421: Poppet Reception Unit 610: Parallel Euro 615: Connect Euro 617: Orifice 620: Deliver Euros 681: First supply Euro 682: Second supply Euro 800: Multiple driving devices 810: Driving motor 820: Slewing motor 830: Boom Cylinder 840: Female cylinder 870: Optional cylinder

Claims

Claim 1 A poppet installed in a poppet receiving portion of a housing comprising a parallel passage supplying hydraulic fluid, a transfer passage for delivering hydraulic fluid supplied by the parallel passage, and a poppet receiving portion provided at the confluence point of the parallel passage and the transfer passage, wherein the parallel passage is openable and closable; a valve body coupled to the housing; a main piston installed inside the valve body so as to be reciprocally movable in the direction of the poppet, with one end selectively pressurizing the poppet; a pilot piston installed inside the valve body so as to be reciprocally movable in the direction of the poppet, with one end selectively pressurizing the main piston; and a pilot port coupled to the valve body to transmit pilot pressure to the pilot piston. A priority valve comprising a connecting passage that connects the parallel passage to the interior of the valve body, wherein an annular chamber is formed inside the valve body to pressurize the pilot piston toward the main piston, and the connecting passage connects the parallel passage and the annular chamber, wherein when the pressure within the parallel passage is the supply reference pressure and the pilot pressure transmitted through the pilot port is the pilot reference pressure, the force acting in the direction in which the poppet opens and the force acting in the direction in which the poppet closes are in equilibrium, and the area of ​​one end of the poppet where the pressure within the parallel passage acts is smaller than the hydraulic pressure area of ​​the annular chamber where the pressure within the parallel passage acts through the connecting passage. Claim 2 A priority valve according to claim 1, wherein when the pressure in the parallel flow path decreases below the supply reference pressure, the force in the direction of opening the poppet increases, and when the pressure in the parallel flow path increases above the supply reference pressure, the force in the direction of closing the poppet increases. Claim 3 A priority valve formed such that, in claim 1, when the pressure in the parallel flow path is the supply reference pressure and the pilot pressure transmitted through the pilot port is the pilot reference pressure, the sum of the first force due to the pressure in the parallel flow path applied to the poppet, the second force due to the pressure in the transmission flow path applied to the poppet in the direction in which the poppet opens, and the third force due to the pressure in the transmission flow path applied to the main piston are in equilibrium with the sum of the fourth force due to the pressure in the transmission flow path applied to the poppet in the direction in which the poppet closes, the fifth force due to the pressure in the parallel flow path applied to the pilot piston through the connecting flow path, and the sixth force due to the pilot pressure applied to the pilot piston. Claim 4 In paragraph 3, the first force is the product of the first hydraulic pressure area, which is the area of ​​one end of the poppet blocking the parallel flow path, and the pressure within the parallel flow path; the second force is the product of the second hydraulic pressure area, which is the pressure within the transmission flow path acting on the poppet in the direction in which the poppet opens, and the pressure within the transmission flow path; the third force is the product of the third hydraulic pressure area, which is the total area of ​​the main piston acting on the poppet, and the pressure within the transmission flow path; the fourth force is the product of the fourth hydraulic pressure area, which is the pressure within the transmission flow path acting on the poppet in the direction in which the poppet closes, and the pressure within the transmission flow path; the fifth force is the product of the fifth hydraulic pressure area, which is the hydraulic pressure area of ​​the annular chamber, and the pressure within the parallel flow path; and the sixth force is the product of the sixth hydraulic pressure area, which is the hydraulic pressure area of ​​the pilot piston acting on the pilot pressure, and the pilot pressure, in a priority valve. Claim 5 In paragraph 4, a priority valve in which the fifth hydraulic pressure area is formed to be larger than the first hydraulic pressure area. Claim 6 In paragraph 1, a priority valve having an orifice formed in the connecting path. Claim 7 In claim 1, a priority valve having a hollow internal space formed in the poppet and a through hole formed on the side of the poppet connecting the transmission path and the internal space. Claim 8 In claim 7, the pressure within the transmission path is a priority valve acting in the internal space of the poppet through the passage hole of the poppet. Claim 9 In claim 8, one end of the main piston is inserted into the internal space of the poppet and pressurizes the poppet, a priority valve. Claim 10 A priority valve according to claim 1, further comprising: a poppet spring that elastically supports the poppet in the direction in which the poppet closes; and a pilot spring that elastically supports the pilot piston in the direction in which the pilot piston moves away from the poppet. Claim 11 In item 10, a priority valve in which the force exerted by the poppet spring and the force exerted by the pilot spring cancel each other out. Claim 12 A main hydraulic pump for discharging hydraulic fluid; a plurality of drive devices that operate by receiving hydraulic fluid; a parallel path through which the hydraulic fluid discharged by the main hydraulic pump travels; a plurality of directional control valves each connected in parallel with the parallel path to control the supply of hydraulic fluid to the plurality of drive devices; and a priority valve installed between one selected of the plurality of directional control valves and the parallel path, wherein the priority valve comprises: a poppet installed in the poppet receiving portion of a housing that includes the parallel path, a transfer path for transferring the hydraulic fluid supplied by the parallel path to one selected of the plurality of directional control valves, and a poppet receiving portion provided at the confluence point of the parallel path and the transfer path, such that the parallel path can be opened and closed; a valve body coupled to the housing; a main piston installed inside the valve body to be reciprocally movable in the direction of the poppet, with one end selectively pressurizing the poppet; a pilot piston installed inside the valve body to be reciprocally movable in the direction of the poppet, with one end selectively pressurizing the main piston; and a pilot port coupled to the valve body to transmit pilot pressure to the pilot piston. A hydraulic system comprising a connecting passage that connects the parallel passage to the interior of the valve body, wherein an annular chamber is formed inside the valve body to pressurize the pilot piston toward the main piston, and the connecting passage connects the parallel passage and the annular chamber, wherein when the pressure within the parallel passage is the supply reference pressure and the pilot pressure transmitted through the pilot port is the pilot reference pressure, the force acting in the direction in which the poppet opens and the force acting in the direction in which the poppet closes are in equilibrium, and the area of ​​one end of the poppet where the pressure within the parallel passage acts is smaller than the hydraulic pressure area of ​​the annular chamber where the pressure within the parallel passage acts through the connecting passage. Claim 13 In paragraph 12, the above supply reference pressure is a hydraulic system in which the pressure within the parallel flow path is when the working fluid discharged by the main hydraulic pump is supplied to any one of the plurality of driving devices. Claim 14 A hydraulic system according to claim 13, wherein when two or more driving devices, including the driving device receiving hydraulic fluid from the directional control valve connected to the priority valve among the plurality of driving devices, operate simultaneously, the pressure of the hydraulic fluid supplied through the parallel path is reduced so that the pressure within the parallel path decreases below the supply reference pressure, thereby increasing the force in the direction in which the poppet opens, and the supply of hydraulic fluid to the directional control valve connected to the priority valve takes precedence over other directional control valves. Claim 15 In claim 14, the plurality of driving devices includes a boom cylinder, an arm cylinder, a swing motor, and an optional cylinder, and the directional control valve controlling the supply of hydraulic fluid to the optional cylinder is a hydraulic system that receives hydraulic fluid through the priority valve.

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