KR20250103582A - Valve, hydraulic system, construction machine and piston - Google Patents

Abstract

The valve of the present invention comprises a housing having a receiving space for storing an operating fluid, and a movable valve body that is received in the receiving space and, when a predetermined or higher pressure is applied and the operating fluid stagnates, moves within the receiving space to discharge the operating fluid accumulated within the receiving space out of the receiving space.

Description

VALVE, HYDRAULIC SYSTEM, CONSTRUCTION MACHINE AND PISTON

The present invention relates to a valve, a hydraulic system, a construction machine, and a movable valve body applied to the automation of hydraulic control.

As a hydraulic circuit for construction machinery, a hydraulic circuit having a proportional solenoid valve for a control valve is increasing. The proportional solenoid valve is composed of a precision part that operates by a small thrust generated by a solenoid or a pressure countermeasure of a small spool. Therefore, a filter is provided on the upstream side of the proportional solenoid valve. The filter captures foreign substances (contamination) on the upstream side of the proportional solenoid valve to prevent them from entering the proportional solenoid valve. For example, according to the technology described in reference to Patent Document 1, the size of the mesh of the filter mesh is made small, thereby protecting the solenoid valve and suppressing clogging of the filter.

Japanese Patent Publication No. 6-81815

However, if the filter aperture is made fine in order to prevent foreign substances from being mixed into the proportional solenoid valve, the viscosity of the working fluid increases at low temperatures, which increases the pressure loss of the working fluid when the working fluid passes through the filter. Therefore, in the proportional solenoid valve, for example, when the viscosity of the working fluid is high at low temperatures, or when the proportional solenoid valve is operated abruptly, the working fluid is likely to remain in the filter portion when the solenoid valve is switched ON/OFF. As a result, there is a concern that a delay in the response may occur in the conventional proportional solenoid valve.

The present invention aims to provide a valve, a hydraulic system, a construction machine and a movable valve body capable of reducing the delay in the response of a proportional solenoid valve.

A valve according to one embodiment of the present invention comprises a housing having a receiving space for receiving a working fluid flowing from an upstream side to a downstream side, a hydraulic portion that is received in the receiving space and receives a pressure of the working fluid stagnant on the upstream side in the receiving space, and a moving valve body that moves from the upstream side toward the downstream side within the receiving space by the pressure applied to the hydraulic portion and discharges the working fluid on the downstream side within the receiving space to the outside of the receiving space.

By configuring in this way, when the viscosity of the working fluid is high at low temperatures, when the proportional solenoid valve is operated abruptly, or when a pressure higher than a predetermined value is applied to the movable valve body when the solenoid valve is switched ON/OFF, even if the working fluid stagnates in the middle of the flow path, the movable valve body moves by the pressure of the working fluid remaining on the upstream side of the receiving space. Thereby, the working fluid accumulated on the downstream side of the receiving space (oil accumulation space) is supplied to the outside of the receiving space. Therefore, when the proportional solenoid valve is provided on the downstream side of the valve, for example, the delay in the response of the proportional solenoid valve can be reduced.

As the above configuration, the moving valve body may have a discharge port for discharging the operating fluid.

By configuring in this way, the operating fluid can be discharged from the discharge port as the moving valve body moves.

As the above configuration, the moving valve body may be provided in the hydraulic section and have a path through which the working fluid flows from the upstream side toward the downstream side, and a filter provided in the path.

By configuring in this way, the filter's eye is made finer, thereby improving the foreign substance capturing performance, and the delay in the response of the proportional solenoid valve can be reduced.

As the above configuration, when the movable valve body moves, a bypass path different from the receiving space that communicates with the upstream side of the hydraulic pressure unit in the receiving space and allows the working fluid to flow by bypassing the downstream side of the hydraulic pressure unit in the receiving space, and another filter provided in the bypass path may be provided.

By configuring in this way, in addition to the operating fluid being supplied from the oil accumulation space to the downstream side, the operating fluid that has passed through another filter is also supplied to the downstream side from the bypass path, so that the delay in the response of the proportional solenoid valve can be further reduced.

As the above configuration, a plug may be provided that is inserted into the receiving space and regulates the operating range of the moving valve body within the receiving space.

By configuring in this way, it is possible to realize a valve having a sliding movable valve body with a small number of parts.

A valve according to one embodiment of the present invention comprises a housing having a receiving space for receiving a working fluid flowing from an upstream side to a downstream side, a hydraulic unit for receiving a pressure of the working fluid stagnant on the upstream side in the receiving space, an outlet for discharging the working fluid on the downstream side of the receiving space to the outside of the receiving space, a flow path provided in the hydraulic unit for allowing the working fluid to flow from the upstream side toward the downstream side, and a filter provided in the flow path, the valve comprising a movable valve body that moves from the upstream side toward the downstream side within the receiving space by pressure applied to the hydraulic unit and discharges the working fluid to the outside of the receiving space through the outlet, and a plug that is fitted into the receiving space and regulates a range of motion of the movable valve body within the receiving space.

By configuring in this way, when the viscosity of the working fluid is high at low temperatures, when the proportional solenoid valve is operated abruptly, when a pressure higher than a predetermined value is applied to the movable valve body when the solenoid valve is switched ON/OFF and the working fluid stagnates, even if the working fluid stagnates in the middle of the flow path, the movable valve body moves by the pressure of the working fluid remaining on the upstream side of the receiving space. Thereby, the working fluid accumulated on the downstream side (oil accumulation space) of the receiving space is supplied to the outside of the receiving space. Therefore, when the proportional solenoid valve is provided on the downstream side of the valve, for example, the delay in the response of the proportional solenoid valve can be reduced.

A hydraulic system according to one embodiment of the present invention is a hydraulic system comprising: an engine as a driving source; a hydraulic pump driven by the engine to distribute a working fluid; a plurality of actuators that drive an operating target by the pressure of the working fluid; a proportional solenoid valve that switches the operations of the plurality of actuators; a housing that is installed upstream of the proportional solenoid valve and has a receiving space that receives the working fluid flowing from the upstream side to the downstream side; a valve that has a hydraulic pressure unit that receives the pressure of the working fluid stagnant on the upstream side in the receiving space, and has a moving valve body that moves from the upstream side toward the downstream side within the receiving space by the pressure applied to the hydraulic pressure unit and discharges the working fluid on the downstream side within the receiving space to the outside of the receiving space; a tank that stores the working fluid; and a relief valve for adjusting the pressure of the working fluid.

By configuring it in this way, when the hydraulic system is configured such that the viscosity of the working fluid is high at low temperatures, the moving valve body moves when a pressure higher than a predetermined value is applied to the moving valve body and the working fluid stagnates. As a result, the working fluid accumulated in the downstream side (oil accumulation space) of the receiving space is supplied to the outside of the receiving space, so that the delay in the response of the proportional solenoid valve can be reduced.

According to one embodiment of the present invention, a construction machine comprises: an engine as a driving source; a hydraulic pump driven by the engine to distribute a working fluid; a plurality of actuators driving an operating target by the pressure of the working fluid; a proportional solenoid valve switching the operations of the plurality of actuators; a housing installed upstream of the proportional solenoid valve and having a receiving space for receiving the working fluid flowing from the upstream side to the downstream side; and a valve having a hydraulic pressure unit that receives the pressure of the working fluid stagnant on the upstream side in the receiving space, the valve having a moving valve body that moves from the upstream side toward the downstream side within the receiving space by the pressure applied to the hydraulic pressure unit and discharges the working fluid on the downstream side within the receiving space to the outside of the receiving space; a tank that stores the working fluid; and a relief valve for adjusting the pressure of the working fluid; a swing body operated by the hydraulic system; and a traveling body that rotatably supports the swing body and is driven by the hydraulic system to travel.

By configuring in this way, when the viscosity of the working fluid is high at low temperatures, when the proportional solenoid valve is operated abruptly, or when a pressure higher than a predetermined value is applied to the movable valve body when the solenoid valve is switched ON/OFF, even if the working fluid stagnates in the middle of the flow path, the movable valve body moves by the pressure of the working fluid remaining on the upstream side of the receiving space. Thereby, the working fluid accumulated on the downstream side of the receiving space (oil accumulation space) is supplied to the outside of the receiving space. Therefore, for example, when the proportional solenoid valve is provided on the downstream side of the valve, the delay in the response of the proportional solenoid valve can be reduced, and a construction machine having a quick response to the operation can be realized.

A moving valve body according to one embodiment of the present invention is provided in a housing and accommodated in a receiving space that receives an operating fluid flowing from an upstream side to a downstream side, and has a hydraulic pressure portion that receives the pressure of the operating fluid stagnant on the upstream side in the receiving space, and moves from the upstream side toward the downstream side within the receiving space by the pressure applied to the hydraulic pressure portion, and discharges the operating fluid on the downstream side within the receiving space to the outside of the receiving space.

By configuring in this way, a sliding movable valve body can be realized with a small number of parts.

According to the present invention, the delay in the response of a proportional solenoid valve can be reduced.

Figure 1 is a schematic diagram of a construction machine according to an embodiment of the present invention.
Figure 2 is a configuration diagram of a hydraulic system according to an embodiment of the present invention.
Figure 3 is a configuration diagram of a valve body in an embodiment of the present invention.
FIG. 4 is a drawing showing a state in which operating fluid flows into a valve body in an embodiment of the present invention.
Fig. 5 is a drawing showing a state in which a piston of a valve body moves in an embodiment of the present invention.
Fig. 6 is a drawing showing a modified example of a valve body in an embodiment of the present invention.
Fig. 7 is a drawing showing another modified example of a valve body in an embodiment of the present invention.

Next, an embodiment of the present invention will be described based on the drawings.

(construction machinery)

As shown in Fig. 1, the construction machine (100) is, for example, a hydraulic shovel. The construction machine (100) has a swivel body (101) and a travel body (102). The swivel body (101) is provided so as to be able to swivel on the travel body (102). A hydraulic system (1) is provided on the swivel body (101).

The swivel body (101) is provided with a driver's seat (103) on which an operator can board, a boom (104) having one end movably connected to the swivel body (101) near the driver's seat (103), an arm (105) having one end movably connected to the other end of the boom (the end (tip) on the opposite side to the cab (103)), and a bucket (106) movably connected to the other end of the arm (105) (the end (tip) on the opposite side to the boom (104)). A hydraulic system (1) is provided inside the cab (103). The cab (103), the boom (104), the arm (105), and the bucket (106) are driven by an operating fluid supplied from the hydraulic system (1). The cab (103), the boom (104), the arm (105), and the bucket (106) are examples of moving objects.

(hydraulic system)

As illustrated in FIG. 2, the hydraulic system (1) comprises an engine (120) as a driving source, a hydraulic pump (130) driven by the engine (120), a plurality of actuators (140) that operate each part of the construction machine (100), a hydraulic control valve (150) that switches the operation of the plurality of actuators (140), a tank (160) that stores a working fluid, and a relief valve (300) for pressure adjustment.

The engine (120) is an internal combustion engine that uses gasoline or diesel fuel. The engine (120) has an output shaft (121). The output shaft (121) is connected to a hydraulic pump (130). A pipe Q is connected to the hydraulic pump (130). The hydraulic pump (130) is driven in accordance with the rotation of the output shaft (121). The hydraulic pump (130) supplies a working fluid to the pipe Q. A hydraulic control valve (150) is connected to the pipe Q.

A plurality of actuators (140) are connected to the hydraulic control valve (150) through a branched pipe Q. A plurality of hydraulic control valves (150) are provided. The hydraulic control valve (150) switches the hydraulic pressure of the working fluid flowing through the pipe Q to the plurality of valves and supplies the working fluid to the plurality of actuators (140). The plurality of actuators (140) drive the cap (103), the boom (104), the arm (105), and the bucket (106), etc. The relief valve (300) releases the pressure when the pressure of the flow path in the hydraulic circuit of the hydraulic system (1) becomes a preset value or higher.

In the hydraulic control valve (150), the operating fluid sent by the pilot pump P is supplied through the proportional solenoid valve (170). The pilot pump P is driven based on the operator's operation. A valve (200) is provided on the upstream side of the proportional solenoid valve (170). As illustrated, the hydraulic system (1) has the same number (two) of pilot pumps P as the number of proportional solenoid valves (170). However, the hydraulic system (1) may be configured to share one pilot pump P for a plurality of proportional solenoid valves (170).

Next, the valve (200) provided on the upstream side of the proportional solenoid valve (170) will be described.

As shown in Fig. 3, the valve (200) is provided with a filter F that captures foreign substances. The valve (200) prevents foreign substances from entering the proportional solenoid valve (170). The valve (200) is provided with a piston (201) (moving valve body) that moves according to the pressure value of the working fluid, and a housing (220) that accommodates the piston (201). The housing (220) may be formed integrally as a housing of the hydraulic system (1) or may be formed as a separate body.

The piston (201) is formed in a cylindrical shape with a ceiling. The piston (201) has a cylindrical body part (202). The piston (201) has a top surface (203) (hydraulic part) that closes one end of the body part (202). A cavity (201S) is formed inside the piston (201) by the body part (202) and the top surface (203). An outlet (206) is formed in the body part (202) of the piston (201). The outlet (206) extends in a direction orthogonal to the axis L of the piston (201). The outlet (206) connects the cavity (201S) and a flow path (224) on the downstream side of the piston (201).

The top surface (203) is formed in a cylindrical shape with a predetermined width from one end of the body part (202) to the other end. A flow path (204) is formed on the top surface (203). The flow path (204) penetrates the top surface (203) in the direction of the axial line L of the piston (201). In the flow path (204), an operating fluid flows along the direction of the axial line L of the piston (201). A step (205) is formed on one end of the flow path (204) so as to be larger than the diameter of the other end of the flow path (204). A filter F for capturing foreign substances in the operating fluid is provided on the step (205).

Filter F supplements foreign substances mixed in the working fluid and filters the working fluid during the process in which the working fluid flows into the cavity (201S) from the flow path (233) on the upstream side of the piston (201). With the above configuration, piston (201) distributes the working fluid from the flow path (204) to the outlet (206) through filter F.

The piston (201) is inserted into a receiving space (221) formed in a housing (220) with a return spring S interposed therebetween. The housing (220) movably receives the piston (201) pressurized by the return spring S. The return spring S pressurizes the piston (201) toward the opening direction of the receiving space (221). The return spring S is inserted into the cavity (201S) of the piston (201).

The receiving space (221) is formed as a circular cavity that receives the piston (201). The diameter (inner diameter) of the receiving space (221) is formed to be slightly larger than the outer diameter of the piston (201). The working fluid can enter the receiving space (221) from the gap between the receiving space (221) and the piston (201). However, this gap is very small. Therefore, foreign substances entering the receiving space (221) from the gap are smaller than foreign substances captured by the filter F, and therefore there is no problem even if they enter the proportional solenoid valve (170).

In the receiving space (221), in addition to a space for receiving the piston (201) in the direction of the axial line L, an oil accumulation space (223) for accumulating working fluid is formed. In the receiving space (221), a step (222) is formed at a position corresponding to the discharge port (206) of the piston (201) so as to expand the diameter (inner diameter). The step (222) is formed with a width in the direction of the axial line L so as to always be in communication with the discharge port (206) even when the piston (201) strokes in the direction of the axial line L.

In the housing (220), a flow path (224) (outside of the receiving space (221)) is connected to the step (222). The flow path (224) is connected to the proportional solenoid valve (170). An opening (221A) is formed at one end of the receiving space (221). A closed oil accumulation space (223) is formed at the other end of the receiving space (221). A screw thread (221B) is formed on the inner surface of the opening (221A). A supply plug (230) is fitted into the opening (221A) (receiving space (221)) so as to cover the opening (221A).

The supply plug (230) is formed in a cylindrical shape. One end of the supply plug (230) is formed with a screw thread (231) that is screw-fitted (engaged) with a screw thread (221B). The supply plug (230) is formed with a step (232) that contacts the housing (220) when it is screwed (fastened) into the opening (221A). The supply plug (230) is fastened to the opening (221A) while the piston (201) pressurized by the return spring S is pressed in, and when the step (232) contacts the housing (220), the piston (201) is confined in the receiving space (221) of the housing (220).

Hereby, the piston (201) is pressurized by the return spring S so that the top surface (203) within the receiving space (221) comes into contact with the supply plug (230). That is, the top surface (203) divides the receiving space (221) into an upstream side (plug (230) side) and a downstream side (oil accumulation space (223) side). The upstream side (plug (230) side) and the downstream side (oil accumulation space (223) side) of the receiving space (221) are connected by a flow path (204). The cross-sectional area perpendicular to the axis L direction of the flow path (204) is smaller than the cross-sectional area perpendicular to the axis L direction of the oil accumulation space (223). When an external force is applied toward the opposite side to the opening (221A), the piston (201) slides in the direction in which the return spring S contracts. In this way, the supply plug (230) regulates the range of motion within the receiving space (221) of the piston (201). That is, the piston (201) is positioned by the supply plug (230). In this way, the supply plug (230) can realize a valve (200) having a slidable piston (201) with a small number of parts.

A flow path (233) is formed in the supply plug (230). The flow path (233) is formed in a through hole that penetrates the supply plug (230) in the direction of the axis L. The flow path (233) has an inlet (234), an outlet (235), and a middle portion (236).

The inlet (234) is connected to the upstream side of the middle part (236). The inlet (234) is formed with a diameter larger than the diameter (cross-sectional area of the flow path) of the middle part (236).

The outlet (235) is connected to the downstream side of the middle part (236). The outlet (235) is formed with a diameter larger than the diameter of the middle part (236).

The middle part (236) is formed with a uniform diameter along the axis L direction. The flow path (233) distributes the working fluid to the flow path (204) through the filter F.

Next, the operation of the valve (200) will be described.

The following description will explain the operation of the valve (200) when the working fluid flows into the passage (233) from the outside of the supply plug (230) in the case where the viscosity of the working fluid is high at low temperatures, when the proportional solenoid valve (170) is operated abruptly, or when the ON/OFF switching of the proportional solenoid valve (170) occurs. As illustrated in FIG. 4, the working fluid that has passed through the passage (233) experiences a pressure loss when circulating through the filter F. In this case, the working fluid cannot completely pass through the filter F and may stagnate in the filter F portion (inside the filter F and upstream from the top surface (203)). As the working fluid stagnates in the filter F portion, the pressure of the working fluid received in the filter F portion increases. As a result, the piston (201) is pressed toward the downstream side of the receiving space (221) by the pressure of the working fluid applied to the filter F portion.

As illustrated in FIG. 5, when the pressure of the working fluid applied to the filter F portion becomes a predetermined value or more, the piston (201) moves in the direction in which the return spring S contracts (from the upstream side to the downstream side of the receiving space (221). When the piston (201) moves, the piston (201) discharges the working fluid in the volume that the piston (201) has moved from the oil accumulation space (223) in the receiving space (221) from the discharge port (206) to the flow path (224). When the flow (e.g., viscosity, pressure, flow rate, etc.) of the working fluid flowing into the flow path (233) returns to a cylindrical state, the working fluid passes through the filter F. Thereby, the pressure of the working fluid applied to the piston (201) (filter F portion) becomes less than the predetermined value. Then, the piston (201) is pushed back toward the supply plug (230) by the return spring S. The working fluid flows into the cavity (201S) through the filter F and is discharged from the discharge port (206). The working fluid discharged from the discharge port (206) flows into the flow path (224) on the downstream side. In the present embodiment, the above-described predetermined value is a resultant force of the restoring force of the return spring S and the force acting on the piston (201) (top surface (203)) due to the pressure in the oil accumulation space (223). That is, the piston (201) moves in the direction in which the return spring S contracts when the pressure applied to the filter portion F becomes greater than the resultant force.

As described above, according to the valve (200), even when a pressure loss of the working fluid occurs in the filter F due to an operation such as abrupt operation of the proportional solenoid valve (170), the piston (201) moves to introduce the working fluid accumulated in the oil accumulation space (223) into the oil passage (224). As a result, the working fluid can be supplied without stagnation in the proportional solenoid valve (170), thereby reducing the delay in the response of the proportional solenoid valve (170).

[Variation]

As illustrated in Fig. 6, a bypass flow path (250) may be provided in the valve (200). The bypass flow path (250) is connected to the flow path (224) from near the top surface (203) of the piston (201). The bypass flow path (250) is a flow path different from the receiving space (221). The bypass flow path (250) bypasses the oil accumulation space (223) and connects the upstream side of the receiving space (221) and the flow path (224). The upstream end of the bypass flow path (250) is connected to a side upstream of the oil accumulation space (223) among the receiving spaces (221). The upstream end of the bypass flow path (250) is switched between communication and blocking with the receiving space (221) by the top surface (203) as the piston (201) moves. The downstream end of the bypass flow path (250) is connected to the flow path (224). In the middle of the bypass flow path (250), another filter F1 different from the filter F is provided.

When the piston (201) moves, the top surface (203) moves downstream, so that the upstream end of the bypass flow path (250) opens upstream of the oil accumulation space (223) in the receiving space (221). As a result, the bypass flow path (250) and the flow path (233) are connected via the receiving space (221). In this way, the flow path (233) is short-circuited to the flow path (224) on the downstream side through the bypass flow path (250). As a result, the working fluid flows out from the flow path (233) to the flow path (224) through the bypass flow path (250). According to the valve (200) having the bypass flow path (250), in addition to the working fluid accumulated in the oil accumulation space (223) being supplied to the flow path (224) on the downstream side, the working fluid is also supplied from the bypass flow path (250). As a result, the delay in the response of the proportional solenoid valve (170) can be reduced.

In addition, the present invention is not limited to the above-described embodiment, but includes various modifications to the above-described embodiment without departing from the scope of the present invention. In the above-described embodiment, a hydraulic system in which the working fluid is working oil has been exemplified, but the valve according to the embodiment may be applied to a hydraulic system in which alcohol, water, or fuel is used as the working fluid in addition to being operated by hydraulic pressure. In the above-described embodiment, a configuration in which a step (222) is formed so as to have an enlarged diameter at a position corresponding to the discharge port (206) of the piston (201) has been exemplified, but as illustrated in FIG. 7, the step (222) may be formed on the outer peripheral side of the piston (201).

In the above embodiment, a configuration in which a filter F is provided in the euro (204) has been described, but a configuration without a filter F may also be used.

In the above embodiment, a configuration has been described in which the upstream side and the downstream side of the receiving space (221) are connected through a path (204) formed on the top surface (203). However, the upstream side and the downstream side of the receiving space (221) may be connected through, for example, a gap between the housing (220) and the piston (201), or may be connected through another path.

In the above embodiment, the piston (201) is described as having a body part (202) and an exhaust port (206). However, the piston (201) may have a configuration that does not have a body part (202) or an exhaust port (206), as long as it has at least a top surface (203) (hydraulic portion).

1: Hydraulic system
100: Construction Machinery
101: Swivel
102: Driving Body
103: Cap
104: Boom
105: Cancer
106: Bucket
120: Engine
121: Output shaft
130: Hydraulic pump
140: Actuator
150: Hydraulic control valve
160: Tank
170: Proportional solenoid valve
200: valve
201: Piston (moving valve body)
201S: Joint
202: Body part
203: Normal surface
204: Euro
205: Step
206: exhaust port
220: Housing
221: Reception space
221A : Opening
221B: Screw thread
222: Step
223: Oil accumulation space
224: Euro
230: Supply plug
231: Screw thread
232: Step
233: Euro
234: Entrance
235: Exit
236: Middle part
250: Bypass Euro
300: Relief valve
F: Filter
F1: Filter
L: Axis line
P: Pilot pump
Q: Plumbing
S: Return spring

Claims (8)

A housing having a receiving space for receiving a working fluid flowing from the upstream side to the downstream side,
Equipped with a piston accommodated in the above accommodation space,
The piston receives the pressure of the working fluid stagnant on the upstream side in the receiving space, and has a hydraulic section that divides the receiving space into the upstream side and the downstream side.
A valve in which the piston moves from the upstream side to the downstream side within the receiving space by the pressure applied to the upstream side with respect to the hydraulic section, thereby discharging the working fluid on the downstream side with respect to the piston within the receiving space to the outside of the receiving space. In the first paragraph,
The above piston has a valve having a discharge port for discharging the working fluid. In the second paragraph,
The above piston,
A flow path provided in the above hydraulic section and through which the working fluid flows from the upstream side to the downstream side,
A valve having a filter provided in the above euro. In any one of claims 1 to 3,
A valve having a plug that is inserted into the above-described receiving space and regulates the range of motion of the piston within the above-described receiving space. A housing having a receiving space for receiving a working fluid flowing from the upstream side to the downstream side,
In the above-mentioned receiving space, the working fluid stagnant on the upstream side receives a pressure, and the working fluid is divided into the upstream side and the downstream side in the above-mentioned receiving space, a discharge port for discharging the working fluid on the downstream side of the above-mentioned receiving space to the outside of the above-mentioned receiving space, a flow path provided in the above-mentioned receiving space for the working fluid to flow from the upstream side toward the downstream side, and a filter provided in the flow path, and a piston accommodated in the above-mentioned receiving space, and a plug fitted into the above-mentioned receiving space for regulating the range of motion of the piston within the above-mentioned receiving space,
A valve in which the piston moves from the upstream side to the downstream side within the receiving space by the pressure applied to the upstream side with respect to the hydraulic section, thereby discharging the working fluid on the downstream side with respect to the piston within the receiving space to the outside of the receiving space. The engine that serves as the driving force,
A hydraulic pump driven by the above engine to distribute working fluid,
A plurality of actuators that drive an object of operation by the pressure of the above working fluid,
A proportional solenoid valve for switching the operation of the above plurality of actuators,
A valve having a housing installed on the upstream side of the proportional solenoid valve and having a receiving space for receiving the working fluid flowing from the upstream side to the downstream side, and having a hydraulic pressure section that divides the receiving space into the upstream side and the downstream side while receiving the pressure of the working fluid stagnant on the upstream side in the receiving space, and having a piston received in the receiving space;
A tank for storing the above working fluid,
It is provided with a relief valve for adjusting the pressure of the above working fluid,
A hydraulic system in which the piston moves from the upstream side to the downstream side within the receiving space by pressure applied to the upstream side with respect to the hydraulic pressure section, thereby discharging the working fluid on the downstream side with respect to the piston within the receiving space to the outside of the receiving space. A hydraulic system comprising an engine as a driving source, a hydraulic pump driven by the engine to distribute working fluid, a plurality of actuators that drive an object of operation by the pressure of the working fluid, a proportional solenoid valve that switches the operations of the plurality of actuators, a housing installed upstream of the proportional solenoid valve and having a receiving space for receiving the working fluid flowing from the upstream side to the downstream side, a piston received in the receiving space, a tank for storing the working fluid, and a relief valve for adjusting the pressure of the working fluid.
A swivel body operated by the above hydraulic system,
The above-mentioned rotating body is provided with a driving body that rotatably supports the above-mentioned rotating body and is driven by the above-mentioned hydraulic system.
The piston receives the pressure of the working fluid stagnant on the upstream side in the receiving space, and has a hydraulic section that divides the receiving space into the upstream side and the downstream side.
A construction machine in which the piston moves from the upstream side to the downstream side within the receiving space by the pressure applied to the upstream side with respect to the hydraulic pressure section, thereby discharging the working fluid on the downstream side with respect to the piston within the receiving space to the outside of the receiving space. A piston having a receiving space provided in a housing so as to divide the receiving space into the upstream side and the downstream side for receiving a working fluid flowing from the upstream side to the downstream side, and having a hydraulic pressure unit that receives the pressure of the working fluid stagnant on the upstream side in the receiving space, and by moving from the upstream side toward the downstream side within the receiving space by the pressure applied to the upstream side with respect to the hydraulic pressure unit, the working fluid on the downstream side within the receiving space with respect to the hydraulic pressure unit is discharged to the outside of the receiving space.