JP2013257023A - Poppet valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the controllability of an opening area in a specific range by steppingly changing the lift amount of a valve element according to a change of pressure in a control pressure chamber.SOLUTION: A cylindrical first projecting part 44 projecting from the position of a valve 36D into a communication hole 24A and a second projecting part 45 which projects from the distal end of the first projecting part 44 (namely, the position of a stepped surface 46) into the communication hole 24A and which is formed smaller in diameter than the first projecting part 44 are provided to the cylindrical projecting part 38E of a valve element 37. The first projecting part 44 and the second projecting part 45 are configured to steppingly change the pressure-receiving area of the valve element 37 against an inlet side passage 24 and an outlet side passage 25. Consequently, the change of a lift amount X according to a change of pressure in a control pressure chamber 42 can be suppressed within a range where the opening area of a poppet valve 36 is in an intermediate opening area.

Description

  The present invention relates to a poppet valve that is provided, for example, in a hydraulic circuit of a construction machine and is preferably used to open and close a flow path of a fluid containing an oil liquid or to adjust a flow rate.

  In general, in a hydraulic circuit used in a construction machine such as a hydraulic excavator, a poppet valve is used to open and close a flow path in a valve housing and adjust a flow rate (see, for example, Patent Document 1). ). In this type of conventional poppet valve, an inlet-side channel and an outlet-side channel intersecting each other are provided in the housing, and a seat portion is provided on the connection end side where the inlet-side channel intersects the outlet-side channel. Is provided. The housing is provided with a poppet-type valve body that is separated from and seated on the seat portion to communicate and block between the flow paths, and a valve spring that normally biases the valve body in the valve closing direction. ing.

  The said valve body interrupts | blocks between an entrance side flow path and an exit side flow path, when sitting on the said seat part. On the other hand, when the valve body is separated from the seat portion, the inlet-side channel and the outlet-side channel communicate with each other, and the flow rate of the fluid is variably adjusted according to the lift amount. The lift amount of the valve body is determined by the pressure of the inlet side channel, the pressure of the outlet side channel, the pressure of the control pressure chamber in which the valve spring is incorporated, and the urging force of the valve spring. A pilot pressure (control pressure) according to an external command is guided to the control pressure chamber, and the lift amount of the valve body of the poppet valve is variably adjusted by changing the pilot pressure.

Japanese Patent No. 3978343

  By the way, in the poppet valve by the prior art mentioned above, a lift amount changes between the fully closed position where the said valve body sits on a seat part, and the fully open position which left | separated most from the seat part. This lift amount is determined by adding the product of the pressure generated in each part of the inlet side channel and the outlet side channel and the pressure receiving area of the valve body in the valve opening direction, and the valve spring when the valve body is lifted. The product of the deflection amount and the spring constant, and the force in the valve closing direction obtained by adding the product of the pressure of the control pressure chamber and the pressure receiving area are determined by a balanced position.

  The pressure in the control pressure chamber varies depending on the pilot pressure introduced into the control pressure chamber or the pressure introduced from the flow path in accordance with the external command. When the pressure in the control pressure chamber is lowered, the force that the valve spring bears increases, and the valve element of the poppet valve moves in the valve opening direction, and when the pressure in the control pressure chamber is raised, the force that the valve spring bears becomes small. Thus, the valve element of the poppet valve moves in the valve closing direction.

  In the prior art poppet valve, since the pressure receiving area of each pressure does not change, the lift amount of the valve body changes in proportion to the pressure of the control pressure chamber, and the opening area of the poppet valve depends on the lift amount. Increase or decrease. That is, the opening area changes according to the pressure in the control pressure chamber. For this reason, in the prior art, when it is desired to control the opening area of a specific range with respect to the pressure of the control pressure chamber within the range of the pressure of the specific control pressure chamber, in particular, the range where the opening area becomes the middle opening region. In the case of control specifications, in order to satisfy the required opening area with a small lift amount of the valve body, for example, it is necessary to take measures such as forming a plurality of notches in the valve body of the poppet valve, which increases the number of processing steps. . Moreover, if the shape of the valve body is formed to be large enough to perform notch processing, there is a problem that the poppet valve is increased in size.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to control the opening area of a specific range by changing the lift amount of the valve body with respect to the pressure change of the control pressure chamber stepwise. An object of the present invention is to provide a poppet valve capable of enhancing the sex.

  In order to solve the above-described problem, the present invention has a first flow path and a second flow path communicating with each other through a communication hole, and a taper shape is formed at an intersection of the second flow path with the communication hole. A housing provided with a seat portion, an annular valve portion which is provided in the housing so as to advance and retreat from the second flow path side into the communication hole, and a front end side of the seat portion is separated from the valve portion. Is formed between the housing and the valve body, and a control pressure for variably controlling the lift amount of the valve body is externally provided. A control pressure chamber that is supplied; and a valve spring that is provided in the control pressure chamber and biases the valve body toward the seat portion in a valve closing direction, and the valve body includes the first flow path and the valve body. The opening area of the communication hole with the second flow path is changed according to the lift amount, It applied to the poppet valve for controlling the flow rate of fluid flowing between the first flow path the second flow path.

  The feature of the configuration adopted by the invention of claim 1 is that the cylindrical projecting portion of the valve body projects in a cylindrical shape from the position of the valve portion toward the inside of the communication hole, and in advance is larger than the hole diameter of the communication hole. A first projecting portion having a small diameter of a predetermined size, and a cylindrical shape projecting from the tip of the first projecting portion into the communication hole and having a smaller diameter than the first projecting portion. A second projecting portion, wherein the first projecting portion and the second projecting portion change the pressure receiving area of the valve body with respect to the first flow path and the second flow path in stages. It is to have done.

  According to a second aspect of the present invention, the projecting length of the second projecting portion is formed so as to be larger than the difference in radial dimension between the first projecting portion and the second projecting portion.

  According to a third aspect of the present invention, the second projecting portion is formed by notching a tip end side end surface thereof, and a plurality of inner surfaces and outer peripheral surfaces of the second projecting portion are communicated in the radial direction. It is set as the structure which provides a notch part.

  As described above, according to the first aspect of the present invention, the cylindrical projecting portion of the valve body is constituted by the first projecting portion and the second projecting portion having a smaller diameter than the first projecting portion, and the first projecting portion. And the second protrusion change the pressure receiving area of the valve body in stages with respect to the first flow path and the second flow path. For this reason, when the pressure (control pressure) in the control pressure chamber is changed, the lift amount of the valve body can be variably adjusted as a characteristic that changes stepwise with respect to the control pressure.

  According to the invention of claim 2, when the lift amount of the valve body is adjusted and the fluid flowing through the communication hole from the first flow path toward the second flow path flows along the second projecting portion of the valve body, A throttling effect can be given to the fluid between the second protrusion and the communication hole, and the flow rate at this time can be adjusted according to the lift amount of the valve body.

  According to the third aspect of the present invention, the plurality of notches formed in the second projecting portion have the first flow when the lift amount of the valve body is increased from the position of the first projecting portion to the position of the second projecting portion. The passage communicates between the communication hole of the passage and the second flow path. For example, the communication area in the large opening region can be controlled by each notch.

It is a whole lineblock diagram showing the case where the poppet valve by a 1st embodiment of the present invention is applied to the hydraulic circuit of a hydraulic excavator. It is a longitudinal cross-sectional view which shows the poppet valve and direction control valve in FIG. It is a longitudinal cross-sectional view which expands and shows the poppet valve in FIG. It is a longitudinal cross-sectional view which expands and shows the valve body which consists of a valve member and a valve holding member in FIG. It is a perspective view which shows the valve member in FIG. 4 as a single unit. FIG. 4 is a longitudinal sectional view substantially similar to FIG. 3 showing a state in which the valve element of the poppet valve is lifted in the range of a small opening. It is a longitudinal cross-sectional view similar to FIG. 6 which shows the state which the valve body of the poppet valve has lifted in the range of the inside opening. It is a longitudinal cross-sectional view substantially the same as FIG. 7 which shows the state which the valve body of a poppet valve has lifted in the range of large opening. It is a characteristic diagram which shows the relationship between the pressure of a control pressure chamber, and the lift amount of a poppet valve. It is a characteristic diagram which shows the relationship between the pressure of a control pressure chamber, and the opening area of a poppet valve. It is a longitudinal cross-sectional view substantially the same as FIG. 8 which shows the poppet valve by 2nd Embodiment.

  Hereinafter, a case where the poppet valve according to the embodiment of the present invention is applied to a hydraulic circuit of a hydraulic excavator will be described as an example and described in detail with reference to the accompanying drawings.

  1 to 10 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a hydraulic excavator as a construction machine. The hydraulic excavator 1 includes a crawler type lower traveling body 2, an upper revolving body 3 that is turnably mounted on the lower traveling body 2, and the upper revolving body. It is comprised by the below-mentioned working apparatus 4 provided in the front part side of the body 3 so that a vertical movement was possible.

  Reference numeral 4 denotes a working device provided at the front of the upper swing body 3. The work device 4 includes a boom 5 whose base end side is attached to the upper swing body 3 so as to be able to be lifted and lowered, and is lifted to the distal end side of the boom 5. An arm 6 that is movably attached, a bucket 7 that is pivotally attached to the distal end side of the arm 6, and a boom 5 that is provided between the upper swing body 3 and the boom 5. A boom cylinder 8 to be moved, an arm cylinder 9 provided between the boom 5 and the arm 6 to move the arm 6 up and down, a bucket cylinder 10 provided between the arm 6 and the bucket 7 to rotate the bucket 7, and the like It is comprised by.

  Reference numeral 11 denotes a main hydraulic pump mounted on the hydraulic excavator 1. The hydraulic pump 11 constitutes a hydraulic pressure source together with a tank 12, and is rotated by a prime mover (not shown) such as a diesel engine. . The hydraulic pump 11 sucks the hydraulic oil in the tank 12 and discharges the pressure oil toward the pump line 13 and the center bypass line 14, and this pressure oil is controlled by a boom control valve 16 and an arm control described later. It is supplied to the boom cylinder 8 and the arm cylinder 9 through the valve 18. Further, between the boom control valve 16 and the arm control valve 18 and the tank 12, for example, a tank pipe line 15 for returning the return oil from the boom cylinder 8 and the arm cylinder 9 to the tank 12 side is provided. ing.

  Here, branch pipes 13A and 13B are provided in the middle of the pump pipe 13, and one of the branch pipes 13A is connected to a high-pressure side port of the arm control valve 18 (that is, the figure) via a poppet valve 36 described later. 2 is connected to an outlet side passage 25) described later. The other branch pipe 13B is connected to a high-pressure side port of a boom control valve 16 described later. The pump line 13 and the tank line 15 are also connected to the bucket cylinder 10 and the like via another branch line, another direction control valve (both not shown), and the like.

  Reference numeral 16 denotes a directional control valve for the boom cylinder 8 (hereinafter referred to as a boom control valve 16). The boom control valve 16 has left and right hydraulic pilot portions 16A and 16B, and is always in a neutral position (i.e. ). The boom control valve 16 is supplied to the left and right hydraulic pilot portions 16A and 16B by, for example, a pilot pressure from a hydraulic pilot type operation valve (not shown). Are switched to switching positions (B) and (C).

  Reference numerals 17A and 17B denote a pair of main pipelines provided between the boom cylinder 8 and the boom control valve 16. One of the main pipelines 17A and 17B is a bottom side oil chamber ( (Not shown) is connected to one pressure oil inflow / outflow port of the boom control valve 16. The other main pipeline 17B connects the rod side oil chamber (not shown) of the boom cylinder 8 to the other pressure oil inflow / outflow port of the boom control valve 16.

  When the boom control valve 16 is switched from the neutral position (A) to the switching position (B), the pressure oil from the hydraulic pump 11 is connected to the boom cylinder via the branch line 13B, the boom control valve 16, and the main line 17A. 8, the pressure oil in the rod side oil chamber is discharged to the tank 12 through the main pipe line 17B, the boom control valve 16, and the tank pipe line 15. As a result, the boom cylinder 8 is extended by the pressure oil supplied to the bottom side oil chamber, and the boom 5 is lifted upward.

  When the boom control valve 16 is switched from the neutral position (A) to the switching position (C), the pressure oil from the hydraulic pump 11 is connected to the boom cylinder via the branch line 13B, the boom control valve 16, and the main line 17B. 8 is supplied to the rod-side oil chamber, and the pressure oil in the bottom-side oil chamber is discharged to the tank 12 via the main conduit 17A, the boom control valve 16, and the tank conduit 15. Thereby, the boom cylinder 8 is contracted by the pressure oil supplied to the rod side oil chamber, and the boom 5 is swung downward.

  Reference numeral 18 denotes a directional control valve for the arm cylinder 9 (hereinafter referred to as an arm control valve 18). The arm control valve 18 has left and right hydraulic pilot portions 18A and 18B, and is always in a neutral position (a ). The arm control valve 18 is supplied with a pilot pressure from, for example, a hydraulic pilot type operation valve (not shown) to the left and right hydraulic pilot portions 18A and 18B, so that the neutral position (A) Are switched to switching positions (B) and (C).

  19A and 19B are a pair of main pipelines provided between the arm cylinder 9 and the arm control valve 18, and one of the main pipelines 19A and 19B is a bottom side oil chamber ( (Not shown) is connected to one pressure oil inflow / outflow port of the arm control valve 18 (that is, the outflow / inflow passage 28A shown in FIG. 2). The other main pipe line 19B connects the rod side oil chamber (not shown) of the arm cylinder 9 to the other pressure oil inflow / outflow port of the arm control valve 18 (that is, the outflow / inflow passage 28B shown in FIG. 2). Is.

  When the arm control valve 18 is switched from the neutral position (A) to the switching position (B), the pressure oil from the hydraulic pump 11 is branched from the branch pipe 13A, an inlet side passage 24, a poppet valve 36, and an outlet side passage described later. 25, the arm control valve 18 and the main line 19A are supplied to the bottom side oil chamber of the arm cylinder 9, and the pressure oil in the rod side oil chamber is supplied to the main line 19B, the arm control valve 18 and the tank line 15; And then discharged to the tank 12. As a result, the arm cylinder 9 is extended by the pressure oil supplied to the bottom side oil chamber, and the arm 6 is swung downward.

  When the arm control valve 18 is switched from the neutral position (A) to the switching position (C), the pressure oil from the hydraulic pump 11 is branched from the branch pipe 13A, an inlet side passage 24, a poppet valve 36, and an outlet side passage. 25, the arm control valve 18 and the main pipe line 19B are supplied to the rod side oil chamber of the arm cylinder 9, and the pressure oil in the bottom side oil chamber is supplied via the main pipe line 19A, the arm control valve 18 and the tank pipe line 15. And discharged to the tank 12. As a result, the arm cylinder 9 is contracted by the pressure oil supplied to the rod side oil chamber, and the arm 6 is lifted upward.

  20 is a relief valve of variable set pressure type, and the relief valve 20 is provided between the pump line 13, the center bypass line 14 and the tank line 15. The relief valve 20 opens, for example, when the pressure in the pump line 13 rises above a set pressure, and relieves excess pressure at this time to the tank line 15 side. Here, the relief valve 20 includes a pressure setting spring 20A, a pilot oil chamber 20B, and the like, and the set pressure of the pressure setting spring 20A is changed according to the pilot pressure supplied to the pilot oil chamber 20B from the outside. As a result, the relief valve 20 has a configuration in which the relief set pressure can be adjusted in multiple stages of two stages or three or more stages between the low pressure setting and the high pressure setting.

  A control valve device 21 includes a poppet valve 36 and an arm control valve 18 which will be described later. The control valve device 21 is common to the arm control valve 18 and the poppet valve 36 as shown in FIG. It has a valve casing 22 as a housing. The valve casing 22 has a spool sliding hole 23 extending through in the left and right directions, and an inlet side as a first flow path formed at a position spaced radially from the spool sliding hole 23. A passage 24 and an outlet-side passage 25 as a second flow path are provided that intersect with the inlet-side passage 24 at the position of the communication hole 24A and extend in an inverted U shape as a whole.

  The communication hole 24 </ b> A of the inlet side passage 24 is disposed at a position facing a valve body sliding hole 27 (described later) across the outlet side passage 25, and communicates so that the inlet side passage 24 intersects the outlet side passage 25. It is what Further, a tapered seat portion 26 as an annular valve seat on which a later-described valve body 37 is attached and detached is provided at an intersection portion of the outlet side passage 25 with the communication hole 24A.

  Further, the valve casing 22 includes a valve body sliding hole 27 including a stepped hole disposed on the opposite side of the inlet side passage 24 across the communication hole 24A, the outlet side passage 25 and the seat portion 26, and the outlet side. A pair of pressure oil inflow / outflow ports of the arm control valve 18 that are spaced apart in the left and right directions (arrows A and B directions in which a spool 29 described later slides) across the passage 25 and the valve body sliding hole 27. The inflow / outflow passages 28A and 28B are formed. The valve body sliding hole 27 extends between a later-described valve block 34 and the outlet side passage 25 along a direction substantially perpendicular to the spool sliding hole 23 (the radial direction of the spool sliding hole 23). The valve element 37 is inserted into the valve element sliding hole 27 so as to be displaceable.

  On the peripheral wall side of the spool sliding hole 23, first annular oil grooves 23A and 23B spaced apart in the left and right directions (arrow A and B directions in FIG. 2), and the first annular oil grooves 23A, Second annular oil grooves 23C and 23D which are positioned on the outer side in the axial direction of the spool sliding hole 23 relative to 23B and spaced apart from each other in the left and right directions, and the spool sliding hole more than the second annular oil grooves 23C and 23D The third annular oil grooves 23E and 23F are formed on the outer side in the axial direction of 23 and spaced apart from each other in the left and right directions.

  The first annular oil grooves 23A and 23B communicate with each other by an outlet-side passage 25 formed in an inverted U shape as a whole, and a spool 29 described later is displaced leftward and rightward from the neutral position shown in FIG. The second annular oil grooves 23C and 23D are communicated and blocked. The second annular oil grooves 23C, 23D are always in communication with the pair of main pipelines 19A, 19B via the left and right inflow / outflow passages 28A, 28B. Further, the third annular oil grooves 23E and 23F are always in communication with the tank 12 via the respective tank conduits 15. The valve casing 22 is formed with a branch passage 25 </ b> A composed of a small diameter oil passage branched from the middle of the outlet side passage 25. This branch passage 25A is always in communication with a passage 34D on the valve block 34 side described later.

  Reference numeral 29 denotes a spool of the arm control valve 18. The spool 29 is inserted into the spool sliding hole 23 of the valve casing 22, and the spool sliding hole according to the pilot pressure supplied from the outside to the hydraulic pilot portions 18A and 18B. 23 slides in the left and right direction. As a result, the arm control valve 18 shown in FIG. 1 is switched from the neutral position (A) to the left and right switching positions (B) and (C).

  As shown in FIG. 2, the spool 29 selectively communicates the second annular oil grooves 23C and 23D with one of the first annular oil grooves 23A and 23B and the third annular oil grooves 23E and 23F. , Switching lands 29A and 29B to be shut off. A plurality of notches 29A1 and 29B1 for finely adjusting the flow rate of the pressure oil are formed in the switching lands 29A and 29B, respectively, spaced apart in the circumferential direction.

  That is, when the spool 29 is slid and displaced in the direction of arrow A in FIG. 2, the switching land 29A of the spool 29 communicates the first annular oil groove 23A with the second annular oil groove 23C, and the spool 29 is switched. The land 29B blocks the first annular oil groove 23B from the second annular oil groove 23D and causes the second annular oil groove 23D to communicate with the third annular oil groove 23F. As a result, the arm control valve 18 is switched from the neutral position (A) shown in FIG. 1 to the left switching position (B).

  On the other hand, when the spool 29 is slid and displaced in the direction indicated by the arrow B in FIG. 2, the switching land 29B of the spool 29 causes the first annular oil groove 23B to communicate with the second annular oil groove 23D. The land 29A blocks the first annular oil groove 23A from the second annular oil groove 23C and causes the second annular oil groove 23C to communicate with the third annular oil groove 23E. Thus, the arm control valve 18 is switched from the neutral position (A) shown in FIG. 1 to the right switching position (C).

  30A and 30B are left and right lids that constitute the arm control valve 18 together with the spool 29. The lids 30A and 30B are located on both sides of the spool sliding hole 23 in the axial direction (left and right). It is provided in the valve casing 22 and closes both end sides of the spool sliding hole 23. Further, hydraulic pilot portions 18A and 18B are provided inside the lid bodies 30A and 30B, and pilot pressure is supplied to the hydraulic pilot portions 18A and 18B from the operation valve. The spool 29 of the arm control valve 18 is slidably displaced leftward and rightward (in the directions indicated by arrows A and B in FIG. 2) in the spool sliding hole 23 according to the pilot pressure at this time.

  Here, the right lid 30B is formed to be longer than the left lid 30A, and a sleeve 31, a stopper 32, a centering spring 33, and the like, which will be described later, are provided in the lid 30B. . Further, the lid 30B is provided with an annular step 30B1 with which the end of the spring 33 abuts as shown in FIG.

  Reference numeral 31 denotes a sleeve provided between the end face of the valve casing 22 and the lid 30B. The sleeve 31 has an inner diameter corresponding to the hole diameter of the spool sliding hole 23, and is spooled in the lid 30B. 29 is slidably supported. Further, the sleeve 31 receives a spring force of a spring 33 to be described later when the spool 29 is in the neutral position as shown in FIG. 2 or is slid and displaced in the direction of arrow B (leftward direction) in FIG. I accept.

  A stopper 32 is screwed to the right end of the spool 29. The stopper 32 is slidably disposed in the lid 30B, and has a shaft 32A extending in the axial direction in the lid 30B. Have. The stopper 32 regulates the stroke end of the spool 29 when the spool 29 is slid and displaced in the arrow A direction (right direction) in FIG.

  Reference numeral 33 denotes a centering spring for holding the spool 29 in a neutral position. The spring 33 is located on the outer peripheral side of the shaft portion 32A, and the end surface of the spool 29 (end surface of the sleeve 31) and the stopper 32 (lid 30B). Between the first step 30B1) and the initial load. The spring 33 holds the spool 29 in the neutral position when the pilot pressure from the hydraulic pilot portions 18A and 18B is reduced to the tank pressure level.

  Further, when the spool 29 is slidably displaced in the direction indicated by arrow A (rightward) in FIG. 2 with the pilot pressure supplied to the hydraulic pilot portion 18A from the outside, the end surface of the spool 29 and the step portion 30B1 of the lid 30B. In between, the spring 33 is compressed and deformed. On the other hand, when the spool 29 is slidably displaced in the direction indicated by arrow B (leftward) in FIG. 2 with the pilot pressure supplied from the outside to the hydraulic pilot portion 18B, the spring 33 is interposed between the end surface of the sleeve 31 and the stopper 32. Is compressed and deformed.

  Reference numeral 34 denotes a valve block that constitutes a housing together with the valve casing 22, and the valve block 34 is provided in contact with the outer surface of the valve casing 22 so as to close the valve body sliding hole 27 of the valve casing 22 from the outside. ing. The valve block 34 has a fitting recess 34A in which a cap member 41 of a poppet valve 36 described later is fitted and attached, a valve receiving hole 34B in which a spool valve body 35A of a pressure adjusting valve 35 described later is stored, A first passage 34C that communicates between the valve accommodation hole 34B and the fitting recess 34A, and a pressure regulation valve 35 that extends obliquely between the branch passage 25A of the valve casing 22 and the valve accommodation hole 34B. A second passage 34D communicated and cut off with respect to the first passage 34C, a pilot pressure supply / discharge port 34E, and a drain port 34F are provided.

  A pressure regulating valve 35 is provided in the valve block 34. The pressure regulating valve 35 is slidably fitted in the valve housing hole 34B of the valve block 34 and has a notch 35A1. A valve body 35A, a cover portion 35B defining a spring chamber on one side of the spool valve body 35A, and a spring 35C provided in a compressed state between the cover portion 35B and the spool valve body 35A. It consists of

  When the pressure regulating valve 35 is disposed at the communication position (a) shown in FIG. 1 by the spring 35C, the pressure regulating valve 35 communicates between the first and second passages 34C and 34D via the spool valve body 35A. Therefore, the back pressure chamber (that is, the control pressure chamber 42) of the poppet valve 36, which will be described later, communicates with the outlet side passage 25 via the first and second passages 34C and 34D and the branch passage 25A on the valve casing 22 side. However, the pressure is kept substantially equal to that of the outlet side passage 25. At this time, the poppet valve 36 is opened to the fully open position as will be described later.

  On the other hand, the spool valve body 35A of the pressure adjusting valve 35 has a predetermined pressure value in which a pilot pressure as an external command pressure supplied to the supply / discharge port 34E from a remote control valve (not shown) for external command is predetermined. When it rises to the above, it slides against the spring 35C and shuts off between the first and second passages 34C, 34D. Thereby, the pressure regulating valve 35 switches from the communication position (a) shown in FIG. 1 to the shut-off position (b) against the spring 35C. For this reason, the control pressure chamber 42 described later is blocked from the second passage 34C (exit side passage 25), acts as described later so as to suppress the lift amount of the valve element 37, and is in the closed position. .

  Reference numeral 36 denotes a poppet valve that constitutes a part of the control valve device 21. The poppet valve 36 includes an inlet side passage 24 (communication hole 24A), an outlet side passage 25, a seat portion 26, and a valve body provided in the valve casing 22. The sliding hole 27 is configured to include a later-described valve body 37, a cap member 41, a control pressure chamber 42, and a valve spring 43. Then, the poppet valve 36 variably adjusts a lift amount (that is, an opening area) of a later-described valve body 37 in cooperation with the pressure adjustment valve 35, and the pressure oil that circulates through the arm control valve 18 according to this. The flow rate is controlled variably.

  Reference numeral 37 denotes a valve body of the poppet valve 36. The valve body 37 includes a stepped valve member 38 inserted into the valve body sliding hole 27 as shown in FIG. A valve holding member 39 that is screwed to the side and holds a later-described check valve body 40 in a displaceable manner with respect to the valve member 38 is formed. The valve holding member 39 has a spring receiving portion 39A that supports a later-described valve spring 43 in a contracted state with the cap member 41, and is formed in a covered cylindrical shape having a smaller diameter than the spring receiving portion 39A. It includes a small-diameter holding cylinder portion 39B that holds a check valve body 40, which will be described later, displaceably in a state of being screwed into a stepped hole portion 38G, which will be described later.

  The valve member 38 includes a large-diameter portion 38A that is slidably inserted into the valve body sliding hole 27, a small-diameter cylindrical portion 38B provided on one side in the axial direction of the large-diameter portion 38A, and a large-diameter portion. A valve portion 38D that is integrally formed on the other side in the axial direction of 38A through a reduced diameter reduced portion 38C and the outer peripheral side of which is seated and seated on the seat portion 26 of the valve casing 22, and the other side (front end side) of the valve portion 38D. A cylindrical projecting portion 38E that projects in the axial direction toward the inside of the communication hole 24A of the inlet side passage 24 is configured. The large diameter portion 38A of the valve member 38 is formed with an outer diameter dimension d1 as shown in FIG. 4, and the outer diameter dimension d1 is slightly smaller than the hole diameter of the valve body sliding hole 27 (that is, the sliding of the valve body 37). It is formed with a small diameter (to the extent that dynamic displacement is allowed).

  Further, the valve member 38 has a check valve body, which will be described later, in the midway portion extending from the inner peripheral side of the cylindrical protruding portion 38E toward the one side (upper side) in the axial direction into the large diameter portion 38A and the small diameter cylindrical portion 38B. A stepped hole 38G in which the valve seat 38F for 40 is formed, and a plurality of radial holes 38H extending in the radial direction of the stepped hole 38G are provided. As shown in FIG. 3, each radial hole 38H communicates with a control pressure chamber 42 described later. The stepped hole portion 38G communicates with the inside of the inlet side passage 24 through the inner peripheral side of the cylindrical protruding portion 38E.

  Furthermore, the cylindrical protrusion 38E of the valve member 38 has a first protrusion 44 and a second protrusion 45 which will be described later. The flow rate of the pressure oil flowing from the inlet side passage 24 to the outlet side passage 25 via the communication hole 24A (that is, the opening area of the communication hole 24A with respect to the outlet side passage 25) is the first protrusion 44 and the second protrusion. The portion 45 is adjusted as described later.

  Reference numeral 40 denotes a check valve body housed between the valve member 38 and the valve holding member 39. The check valve body 40 is slidably inserted into the holding cylinder portion 39B of the valve holding member 39, and is normally fitted. The valve member 38 is biased by a weak spring 40A so as to be seated on the valve seat 38F. When the pressure in the inlet side passage 24 is applied from the cylindrical projecting portion 38E side of the valve member 38, the check valve body 40 opens so as to separate from the valve seat 38F against the weak spring 40A. As a result, the pressure oil in the inlet side passage 24 is supplied to a control pressure chamber 42 described later via the stepped hole 38G of the valve member 38 and the radial holes 38H.

  In this way, the check valve body 40 allows the pressure oil to flow from the inlet side passage 24 toward the control pressure chamber 42 in the valve body 37 and prevents the reverse flow. That is, the check valve body 40 prevents the oil in the control pressure chamber 42 from flowing toward the stepped hole 38G and the inlet-side passage 24 through the radial holes 38H of the valve member 38 and the like. is there.

  41 is a cap member that constitutes a part of the poppet valve 36, and the cap member 41 is fitted into the fitting recess 34 </ b> A of the valve block 34, and the valve body sliding hole 27 of the valve casing 22 is positioned on one side in the axial direction. The valve block 34 is closed from the upper side. Between the valve holding member 39 and the cap member 41 of the valve body 37, a control pressure chamber 42 is formed as a back pressure chamber for variably controlling the lift amount of the valve body 37. The valve block 34 always communicates with the first passage 34C.

  A valve spring 43 is located in the control pressure chamber 42 and is disposed between the valve holding member 39 and the cap member 41. The valve spring 43 is configured by using a coil spring or the like, and a valve element 37 ( The valve holding member 39) is normally biased in the valve closing direction. The valve body 37 is also pressed in the valve closing direction by back pressure (control pressure) generated in the control pressure chamber 42. Further, the valve spring 43 also has a function of preventing the valve body 37 from being inadvertently opened due to, for example, vibration from the outside.

  As the valve spring 43, a spring constant k adjusted is used, and is constituted by a spring having a predetermined spring constant kb as will be described later. That is, in the valve spring 43, when the pressure in the control pressure chamber 42 is a predetermined pressure (the minimum pressure Pmin described later), the lift amount X of the valve element 37 is maximized (the maximum displacement amount Xmax described later). Thus, the spring constant kb is set to a predetermined value.

  Reference numeral 44 denotes a first protrusion that constitutes a cylindrical protrusion 38E of the valve body 37 together with a second protrusion 45 described later. The first protrusion 44 is a cylinder of the valve member 38 as shown in FIGS. It arrange | positions in the position close | similar to the valve part 38D side among the protruding parts 38E, and is slidably inserted in the communicating hole 24A. That is, the first projecting portion 44 is formed as a cylindrical body that projects in a cylindrical shape from the position of the valve portion 38D toward the communication hole 24A. The outer diameter d2 (see FIG. 4) of the first protrusion 44 is a predetermined dimension (a range in which the first protrusion 44 is allowed to slide and displace within the communication hole 24A) than the hole diameter of the communication hole 24A. Only) is formed with a slightly smaller diameter. The outer diameter d2 (see FIG. 4) of the first protrusion 44 is smaller than the outer diameter d1 of the large diameter portion 38A (d2 <d1).

  A plurality of notches 44 </ b> A serving as notches are provided on the outer peripheral surface of the first projecting portion 44 so as to be separated from each other in the circumferential direction. As shown in FIG. 6, in the small opening region (range C shown in FIG. 9) where the lift amount of the valve body 37 is small, the inlet side passage 24 is in a state where the valve portion 38D of the valve body 37 is separated from the seat portion 26. The communication hole 24 </ b> A communicates with the outlet side passage 25 through the notches 44 </ b> A of the first protrusion 44. At this time, the flow rate of the pressure oil flowing from the communication hole 24A toward the outlet side passage 25 is adjusted to a relatively small flow rate within the range of the flow path area (opening area) by each notch 44A.

  45 is a second projecting portion that constitutes the cylindrical projecting portion 38E of the valve body 37 together with the first projecting portion 44, and the second projecting portion 45 is formed of the first projecting portion 44 as shown in FIGS. A cylindrical body protrudes from the tip (step surface section 46 described later) into the communication hole 24 </ b> A and has a smaller diameter than the first protrusion 44. The second protrusion 45 has an axial protrusion length L, and the inner diameter of the second protrusion 45 is the same as that of the first protrusion 44. However, the outer diameter d3 (see FIG. 4) of the second protrusion 45 is smaller than the outer diameter d2 of the first protrusion 44 by a predetermined dimension (d3 <d2).

  Here, the difference δ in the radial direction between the first protrusion 44 and the second protrusion 45 (hereinafter referred to as the radial gap δ) is obtained by the following equation (1). This radial clearance δ is caused by pressure oil flowing between the communication hole 24A and the second protrusion 45 when the lift amount of the valve element 37 is in the middle opening region (range D shown in FIG. 9) as will be described later. The dimensions are such that the diaphragm effect can be exhibited.

  Further, the projecting length L of the second projecting portion 45 is formed to be larger than the radial gap δ (L> δ). If the protrusion length L is made longer, the second protrusion 45 can further enhance the aperture effect accordingly. Further, the second projecting portion 45 is provided with a plurality of notches 45A formed by notching the end surface on the front end side in a U-shaped cross section. The notches 45A are arranged at regular intervals in the circumferential direction of the second protrusion 45 (that is, the cylindrical protrusion 38E), and the radial direction between the inner peripheral surface and the outer peripheral surface of the second protrusion 45 is provided. It is formed as a slot that extends in the direction of communication between the two.

  46 is an annular stepped surface portion disposed between the first projecting portion 44 and the second projecting portion 45, and the stepped surface portion 46 extends over the entire circumference in the circumferential direction of the valve body 37 (cylindrical projecting portion 38E). It is formed as an annular step surface. The step surface portion 46 is a small opening region where the lift amount of the valve element 37 is small as shown in FIG. 6 and serves as a pressure receiving surface for receiving the pressure in the inlet side passage 24, and the lift amount of the valve element 37 as shown in FIG. In the large opening area where the pressure increases, the pressure receiving surface receives the pressure in the outlet side passage 25. Thereby, the level | step difference surface part 46 can exhibit the effect which changes the pressure receiving area of the valve body 37 with respect to the entrance side channel | path 24 and the exit side channel | path 25 in steps.

  The control valve device 21 including the poppet valve 36 according to the first embodiment has the above-described configuration. Next, the operation thereof will be described.

  First, the pressure oil discharged from the hydraulic pump 11 passes from the branch line 13A of the pump line 13 to the inlet side passage 24 of the valve casing 22, the valve body 37 of the poppet valve 36, and the communication hole 24A (gap). It flows to the outlet side passage 25. The pressure oil that has flowed into the outlet-side passage 25 is switched to the arm via the pair of main pipelines 19A and 19B by switching the arm control valve 18 from the neutral position (A) to the switching position (B) or (C). It is supplied to and discharged from the cylinder 9.

  The flow rate of the pressure oil supplied to the arm cylinder 9 is determined by the opening area of the valve element 37 of the poppet valve 36 and the opening area of the spool 29 (switching lands 29A, 29B) of the arm control valve 18. Further, when blocking the flow of the pressure oil from the inlet side passage 24 to the outlet side passage 25 of the valve casing 22, the valve element 37 of the poppet valve 36 connects the valve portion 38 </ b> D of the valve member 38 to the seat of the valve casing 22. The passages 24 and 25 are blocked by being seated on the portion 26.

  Therefore, in order to keep the flow rate of the pressure oil supplied to the arm cylinder 9 through the arm control valve 18 small, the pressure adjustment valve 35 is switched from the communication position (a) to the cutoff position (b). That is, when the spool valve body 35A of the pressure adjusting valve 35 is slidably displaced in the direction of arrow B (leftward) in FIG. 2, the opening area of the pressure adjusting valve 35 (that is, the opening area by the notch 35A1 of the spool valve body 35A). ) Is getting smaller. When the opening area by the notch 35A1 is reduced, a pressure difference is generated between the first and second passages 34C and 34D, and the pressure in the control pressure chamber 42 is increased. As a result, the valve body 37 of the poppet valve 36 is set to a small opening region (range C shown in FIG. 9), with the lift amount being suppressed to a small level by the pressure in the control pressure chamber 42 as shown in FIG.

  When the pressure adjustment valve 35 is completely switched from the communication position (a) to the shut-off position (b), the control pressure chamber 42 of the poppet valve 36 is connected to the second passage 34D by the spool valve body 35A of the pressure adjustment valve 35. This is blocked from the branch passage 25A. As a result, the control pressure chamber 42 of the poppet valve 36 has a pressure substantially equal to that of the inlet-side passage 24, so that the valve element 37 of the poppet valve 36 is fully closed (see FIG. 3).

  In the small opening region shown in FIG. 6, the valve element 37 of the poppet valve 36 has the valve portion 38D of the valve member 38 separated from the seat portion 26 and the first protruding portion 44 of the cylindrical protruding portion 38E is the seat portion 26. Rather than enter the communication hole 24A. In this case, the flow rate of the pressure oil flowing from the communication hole 24A toward the outlet-side passage 25 is determined by the opening area (for example, a plurality of notches 44A) formed between the first protrusion 44 of the valve body 37 and the communication hole 24A. The opening is adjusted to a small flow rate.

  On the other hand, when the pressure adjustment valve 35 is switched from the shut-off position (b) to the communication position (a), the spool valve body 35A of the pressure adjustment valve 35 slides in the direction indicated by arrow A (rightward) in FIG. As a result, the opening area by the notch 35A1 of the spool valve body 35A gradually increases, so that the pressure difference between the first and second passages 34C and 34D gradually decreases and the pressure in the control pressure chamber 42 decreases. Become. As a result, the lift amount of the valve element 37 of the poppet valve 36 gradually increases as shown in FIG. 7, and is set to the middle opening region (range D shown in FIG. 9).

  In the middle opening region shown in FIG. 7, the valve element 37 of the poppet valve 36 has a stepped surface portion 46 between the first protruding portion 44 and the second protruding portion 45 at the boundary between the communication hole 24 </ b> A and the seat portion 26. The valve is opened to reach the position, and the second projecting portion 45 enters the communication hole 24 </ b> A rather than the seat portion 26. In this case, the flow rate of the pressure oil flowing from the communication hole 24A toward the outlet side passage 25 is adjusted to an intermediate flow rate by the opening area formed between the second projecting portion 44 of the valve body 37 and the communication hole 24A. The

  Further, when the pressure adjusting valve 35 is further switched in the direction of the communication position (a) from this state, the spool valve body 35A of the pressure adjusting valve 35 is slid and displaced in the direction indicated by the arrow A (right direction) in FIG. The opening area of the spool valve body 35A (including the opening area by the notch 35A1) gradually increases. For this reason, the pressure difference between the first and second passages 34C, 34D gradually decreases, and the pressure in the control pressure chamber 42 further decreases. Thereby, the lift amount of the valve element 37 of the poppet valve 36 is gradually increased, and is set to a large opening region (range E shown in FIG. 9). FIG. 8 shows a state where the lift amount of the valve body 37 is maximized and the poppet valve 36 is opened to the fully open position.

  Thus, the poppet valve 36 changes the lift amount of the valve element 37 by changing the pressure of the control pressure chamber 42, and the opening area where the inlet side passage 24 communicates with the outlet side passage 25 via the communication hole 24A. Can be adjusted. That is, when the valve element 37 of the poppet valve 36 is in the lift position of the small opening region (range C shown in FIG. 9), the inlet side passage 24 and the outlet side passage 25 are formed on the outer peripheral surface of the first protrusion 44. Communication is made through a plurality of notches 44A provided, and the communication area can be controlled within the range of the small opening region by each notch 44A.

  When the valve element 37 of the poppet valve 36 is in the lift position of the middle opening region (range D shown in FIG. 9), the inlet-side passage 24 and the outlet-side passage 25 are formed between the annular step surface portion 46 and the seat portion 26. And through the opening (gap) between the second protrusion 45 and the communication hole 24A, and the communication area can be controlled within the range of the middle opening region (see FIG. 10).

  When the valve element 37 of the poppet valve 36 is in the lift position in the large opening region (range E shown in FIG. 9), the inlet side passage 24 and the outlet side passage 25 are formed between the second protrusion 45 and the communication hole 24A. The gap is further communicated by a plurality of notches 45A provided in the second protrusion 45, and the communication area can be controlled within the range of the large opening region.

  Here, the lift amount of the valve element 37 of the poppet valve 36 includes the pressures of the inlet side passage 24, the outlet side passage 25 and the control pressure chamber 42 of the valve casing 22, and the pressure receiving area at the portion receiving these pressures. It is determined by the urging force of the valve spring 43. The pressure receiving area S1 where the valve body 37 receives the pressure Px in the control pressure chamber 42 is obtained by the following equation (2) based on the outer diameter d1 (see FIG. 4) of the large diameter portion 38A.

  Further, as shown in FIG. 3, the pressure receiving area S2 (see FIG. 4) where the valve body 37 in the closed state receives the pressure Pi in the inlet passage 24 is as follows depending on the outer diameter d2 of the first protrusion 44. It is calculated by the equation (3). The pressure receiving area S3 on the second projecting portion 45 side of the valve body 37 is obtained by the following equation (4) based on the outer diameter d3 of the second projecting portion 45.

  The pressure receiving area where the valve body 37 receives the pressure Po in the outlet side passage 25 is S4 (not shown), the spring constant of the valve spring 43 is k, and the initial load of the valve spring 43 (that is, the valve body 37 is The force Fa acting in the valve opening direction of the valve element 37 when the spring load at the valve closing position shown in FIG. The force Fb acting in the valve closing direction of the body 37 is expressed by the following equation (6).

  Here, when the force Fa and the force Fb are balanced and the poppet valve 37 stops at an arbitrary position, the following equation (7) is satisfied, and the lift amount X of the valve element 37 is expressed by the following equation (8). , Can be summarized as several tens of equations.

  Further, the force (Fa-F0) in the equation (8) can also be expressed as a force F1 in the valve opening direction acting on the valve element 37 as in the following equation (9). , Can be summarized as the following equation (10).

  Among these formulas 10, the force F1 in the valve opening direction (that is, the force Fa according to the formula 5), the initial load F0 of the valve spring 43, the spring constant k, and the pressure receiving area S1 can be handled as known values in advance. Is possible. For this reason, in the comparative example of the present invention, the lift amount X of the valve element 37 can be expressed by the linear characteristic line 47 using the pressure Px in the control pressure chamber 42 as a variable from the above equation (10). In this case, in the poppet valve according to the comparative example, as in the prior art according to Patent Document 1, the tip of the valve body (the part corresponding to the cylindrical protrusion 38E of the valve body 37) gradually increases the pressure receiving area. The shape to be changed is not formed.

  That is, the characteristic line 47 of the comparative example shown by a two-dot chain line in FIG. 9 shows the lift amount of the valve element 37 by adjusting the pressure Px in the control pressure chamber 42 in the range from the minimum pressure Pmin to the maximum pressure Pmax. X indicates a linear change from the maximum displacement amount Xmax at the fully open position to the fully closed position. In this comparative example, the relationship between the pressure Px in the control pressure chamber 42 and the opening area can be represented by a characteristic line 48 indicated by a two-dot chain line in FIG.

  By the way, in the case of the comparative example in which the lift amount X of the valve body 37 changes along the linear characteristic (characteristic line 47) according to the pressure Px in the control pressure chamber 42, the lift amount X with respect to the pressure Px in the control pressure chamber 42 Therefore, it is not possible to satisfy the requirement to control the opening area of a specific range (for example, range D in FIG. 9) with different characteristics. That is, when it is important to control the poppet valve 36 in the middle opening area (for example, the opening area is from the opening area A1 to the opening area A2 in FIG. 10), the pressure in the control pressure chamber 42 is determined in this area. There is a demand to keep the change in the lift amount small with respect to the change and to make the change characteristic (slope) of the opening area relatively small.

  Therefore, in the first embodiment, in order to satisfy such a requirement, the cylindrical first protruding from the position of the valve portion 38D toward the inside of the communication hole 24A is formed on the cylindrical protruding portion 38E of the valve body 37. A protruding portion 44 and a second protruding portion 45 that protrudes from the tip of the first protruding portion 44 (that is, the position of the stepped surface portion 46) into the communication hole 24A and has a smaller diameter than the first protruding portion 44. Provided. The 1st protrusion part 44 and the 2nd protrusion part 45 are set as the structure which changes the pressure receiving area of the valve body 37 with respect to the entrance side channel | path 24 and the exit side channel | path 25 in steps.

  As described above, in the first embodiment, the first projecting portion 44 and the second projecting portion 45 provided on the cylindrical projecting portion 38 </ b> E of the valve body 37 provide a valve for the inlet side passage 24 and the outlet side passage 25. In order to change the pressure receiving area of the body 37 stepwise, the lift amount X of the valve body 37 can be changed with respect to the pressure Px in the control pressure chamber 42 as shown by a characteristic line 49 shown by a solid line in FIG. In the range D in which the opening area of the poppet valve 36 is the middle opening region, the change in the lift amount X can be suppressed small with respect to the pressure change in the control pressure chamber 42 as in the characteristic line portion 49D.

  That is, as shown in FIG. 8, the large opening region (range E shown in FIG. 9) in which the lift amount X of the valve element 37 is displaced from the position of the maximum displacement amount Xmax to the position where the annular stepped surface portion 46 approaches the seat portion 26. ), The pressure receiving area of the valve body 37 with respect to the high-pressure side inlet-side passage 24 is reduced from the pressure-receiving area S2 shown in FIGS. 4 and 8 to the pressure-receiving area S3. The area increases by the pressure receiving area corresponding to the area (S2-S3).

  When the lift amount X of the valve body 37 reaches the maximum displacement amount Xmax, the pressure Px in the control pressure chamber 42 is the minimum pressure Pmin, and the relationship between the maximum displacement amount Xmax and the minimum pressure Pmin is expressed by the above equation (10). Is expressed by the following equation (11).

  In the comparative example of the characteristic line 47 shown by a two-dot chain line in FIG. 9, when the pressure receiving area of the valve body 37 that receives the pressure Pi of the inlet side passage 24 that is the pressure on the high pressure side is S2, the force F1 in the valve opening direction Is the force F1a, the pressure receiving area S4 that receives the pressure P0 of the outlet side passage 25 is the area S4a, and the spring constant k is ka, the force F1a in the valve opening direction is expressed by the following equations (5) and (9). It can obtain | require by several 12 Formula.

  On the other hand, in the first embodiment, since the cylindrical projecting portion 38E of the valve body 37 has the first projecting portion 44 and the second projecting portion 45, a large opening region (range E shown in FIG. 9). , The pressure receiving area S2 of the valve body 37 that receives the pressure Pi of the inlet side passage 24 decreases to the pressure receiving area S3. At this time, if the force F1b in the valve opening direction is the force F1b, the pressure receiving area S4 of the valve body 37 that receives the pressure Po of the outlet passage 25 is the area S4b, and the spring constant k is kb, the force F1b in the valve opening direction Can be obtained by the following equation (13) based on the equations (5) and (9).

  Here, when the force F1a in the valve opening direction is replaced with the force F1 in the equation (11) and the spring constant k is replaced with ka, the relationship of the following equation (14) is obtained. If the force F1b in the valve opening direction is replaced with the force F1 in the equation (11) and the spring constant k is replaced with kb, the relationship of the following equation (15) is obtained.

  The spring constant ka in the comparative example can be expressed by the following equation 16 from the above equation 14, and the spring constant kb of the valve spring 43 in the first embodiment can be expressed by the following equation 17 from the above equation 15. Can be represented by

  Here, the pressure receiving areas S2 and S3 are in the relationship of the following equation (18), the pressure receiving areas S4a and S4b are in the relationship of the following equation (19), and the pressures Pi and Po are in the relationship of the following equation (20). It is in.

  For this reason, the force F1b in the valve opening direction in the first embodiment is smaller than the force F1a in the valve opening direction in the comparative example, as shown in Equation 21 below. The spring constant kb of the valve spring 43 in the first embodiment is smaller than the spring constant ka in the comparative example, as shown in the following equation (22).

  Thus, in the first embodiment, when the pressure Px of the control pressure chamber 42 is the minimum pressure Pmin, the spring constant kb is set so that the lift amount X of the valve element 37 becomes the maximum displacement amount Xmax. In the case of (spring constant ka), it can be set smaller. As a result, as shown in a range E (that is, a characteristic line portion 49E) in FIG. 9, it is possible to quickly move from the middle opening range to the maximum opening with a small pressure change compared to the characteristic line 47 of the comparative example.

  Next, if the poppet valve 36 has the pressure Pc of the control pressure chamber 42 when the valve element 37 is in the range of the second protrusion 45 (that is, the range D shown in FIG. 9), the characteristic in FIG. The lift amount X of the comparative example by the line 47 is represented by the following equation (23) when the force F1 in the equation (10) is changed to the force F1a in the valve opening direction and the spring constant k is replaced by ka.

  In the poppet valve 36 according to the first embodiment, that is, the valve body 37 having the first and second projecting portions 44 and 45, the valve body is increased as the pressure Pc of the control pressure chamber 42 increases in the range D in FIG. Since the lift amount X of 37 is reduced, the pressure receiving area that receives the pressure Pi of the inlet side passage 24 (high pressure side) gradually increases from the area S3 to the area S2. Conversely, the pressure receiving area that receives the pressure Po in the outlet side passage 25 (low pressure side) gradually decreases from the area S4b to the area S4a.

  If the pressure receiving area that receives the pressure Pi of the changing inlet side passage 24 (high pressure side) is S3c and the pressure receiving area that receives the pressure Po of the outlet side passage 25 (low pressure side) is S4c, the valve element 37 opens direction. The force F1c acting on can be obtained by the following equation (24) from the relationship between the equations (5) and (9).

  Here, the force F1c in the valve opening direction acting on the valve element 37 is in the relationship of the above formula 25, and the force F1c changes from the force F1b to the force F1a as the lift amount X of the valve element 37 decreases. It will be. That is, in the range D in FIG. 9, the force acting in the valve closing direction increases as the pressure Pc in the control pressure chamber 42 increases, but the force F1c acting in the valve opening direction also increases. The displacement of the lift amount X with respect to the pressure Pc of 42 becomes small. As a result, in the range D of the middle opening region shown in FIG. 9, the change in the pressure Px in the control pressure chamber 42 is larger than that in the comparative example shown by the characteristic line 47 as in the characteristic line portion 49D of the characteristic line 49 shown by the solid line. Therefore, control with a small change in lift amount can be performed.

  Next, when the valve element 37 of the poppet valve 36 is in the range of the cylindrical first protrusion 44 (that is, the range C of the small opening region), if the pressure Px of the control pressure chamber 42 is the pressure Pd, the inlet The pressure receiving area that receives the pressure Pi of the side passage 24 (high pressure side) is S2. In the comparative example shown by the characteristic line 47, the pressure Pi of the inlet side passage 24 (high pressure side) is received with the same pressure receiving area S2. For this reason, the lift amount X of both is obtained by replacing the force F1 in the equation (10) with the force F1a in the valve opening direction, replacing the spring constant k with ka and kb, and the pressure Px with the pressure Pd. It becomes the relationship.

  In this case, the poppet valve 36 according to the first embodiment can reduce the spring constant k from the constant ka to the constant kb with respect to the comparative example. Thus, when the pressure Px of the control pressure chamber 42 changes, in the first embodiment, the lift amount X of the valve element 37 is within the small opening region range C shown in FIG. 9 (that is, the characteristic line 49). The characteristic line portion 49C) changes more greatly than the comparative example (characteristic line 47). For this reason, the valve element 37 of the poppet valve 36 can be brought into the closed position with a pressure change smaller than that of the comparative example (change in the pressure Px of the control pressure chamber 42).

  Thus, the poppet valve 36 employed in the first embodiment is formed in the tubular projecting portion 38E of the valve body 37 with the tubular first projecting portion 44 and a smaller diameter than the first projecting portion 44. The 2nd protrusion part 45 is provided, and the 1st protrusion part 44 and the 2nd protrusion part 45 are set as the structure which changes the pressure receiving area of the valve body 37 with respect to the entrance side channel | path 24 and the exit side channel | path 25 in steps. Thereby, the relationship of the lift amount X with respect to the pressure Px of the control pressure chamber 42 can be changed along the characteristic line 49 shown by a solid line in FIG.

  As a result, the relationship between the pressure Px in the control pressure chamber 42 and the opening area of the poppet valve 36 can be as shown by a characteristic line 50 shown by a solid line in FIG. That is, in the small opening area (range C in FIG. 9) where the opening area Ax is smaller than the opening area A1 in FIG. 10 and the large opening area (range E in FIG. 9) where the opening area A2 is larger than the opening area A2. The change in the lift amount X with respect to the pressure Px in the control pressure chamber 42 is increased, whereby the change in the opening area Ax is also greatly changed. In the middle opening region (range D in FIG. 9) of the opening areas A1 to A2, the change in the lift amount X with respect to the change in the pressure Px in the control pressure chamber 42 is small, so the change in the opening area Ax is gentle.

  In this way, by providing the cylindrical first protrusion 44 and the second protrusion 45 on the cylindrical protrusion 38E of the valve body 37, for example, control of the range from the opening area A1 to the opening area A2 shown in FIG. When considering the characteristics, the pressure range of the control pressure chamber 42 that controls the opening when the opening area Ax is larger than the opening area A2 and smaller than the opening area A1 is reduced, and the range from the opening area A1 to the opening area A2 is controlled. By increasing the pressure range of the control pressure chamber 42, the controllability in the range from the opening area A1 to the opening area A2 can be particularly improved.

  On the other hand, in the case of the comparative example indicated by the characteristic line 47, since the change in the lift amount X with respect to the pressure change in the control pressure chamber 42 is constant, the controllability of the opening area in a specific range is improved. For example, when trying to obtain the same opening area A1 at the same pressure position of the control pressure chamber 42 as the valve element 37 of the poppet valve 36 provided with the second protrusion 45, the poppet valve of the comparative example has a small lift amount. Since it is necessary to provide a plurality of notches and a size sufficient to process the plurality of notches is required, the poppet valve is increased in size and the processing time is increased, leading to an increase in cost.

  Further, in the comparative example, in order to obtain the opening area at the maximum lift (maximum displacement amount Xmax), relatively large notches such as the notches 45A provided in the second protrusion 45 of the valve body 37 are formed. In the comparative example, since the lift amount X of the middle opening region (range D in FIG. 9) is limited, the pressure in the control pressure chamber 42 that can control the middle opening region from the opening area A1 to the opening area A2. The range was limited.

  However, in the first embodiment, the cylindrical projecting portion 38E of the valve body 37 is provided with the cylindrical first projecting portion 44 and the second projecting portion 45, and in particular, the middle opening of the opening area A2 from the opening area A1. By reducing the change in the lift amount X with respect to the pressure Px of the control pressure chamber 42 in the region, the pressure range of the control pressure chamber 42 that can be used for controlling the middle opening region can be widened, and the opening area of a specific range can be increased. Controllability can be improved.

  For this reason, when the pressure oil from the hydraulic pump 11 shown in FIG. 1 is supplied to and discharged from the arm cylinder 9 via the poppet valve 36 and the arm control valve 18, and the arm 6 of the working device 4 is moved up and down, the poppet valve The controllability of the opening area in the specific range of 36, that is, the controllability in the middle opening region can be improved.

  Next, FIG. 11 shows a second embodiment of the present invention. In the second embodiment, the same reference numerals are given to the same components as those in the first embodiment described above, and the description thereof will be given. Shall be omitted. However, the feature of the second embodiment is that the second protrusion 51 provided on the distal end side of the first protrusion 44 is formed as a stepped protrusion.

  Here, the second protrusion 51 protrudes in a cylindrical shape from the tip of the first protrusion 44 into the communication hole 24 </ b> A, and has a medium diameter protrusion that is smaller in diameter than the first protrusion 44 by a predetermined dimension. 51A, and a small-diameter protruding portion 51B that protrudes in a cylindrical shape from the tip of the medium-diameter protruding portion 51A into the communication hole 24A and has a smaller diameter than the intermediate-diameter protruding portion 51A. ing. The first protrusion 44 and the second protrusion 51 (the medium-diameter protrusion 51A and the small-diameter protrusion 51B) increase the pressure receiving area of the valve body 37 with respect to the inlet-side passage 24 and the outlet-side passage 25 in three or more stages. The structure is changed.

  The second projecting portion 51 is provided with a plurality of notches 51C formed by notching the end surface on the front end side in a V-shaped cross section. The notches 51C are arranged at regular intervals in the circumferential direction, like the notches 45A described in the first embodiment, and the second protrusions 51 (that is, the medium diameter protrusions 51A and the small diameter protrusions). 51B) is formed as a slot that extends in the radial direction between the inner peripheral surface and the outer peripheral surface and communicates with each other.

  A step surface portion 52 similar to the annular step surface portion 46 described in the first embodiment is formed between the first protrusion portion 44 and the second protrusion portion 51. In the second protrusion 51, another step surface portion 53 is formed between the medium diameter protrusion 51A and the small diameter protrusion 51B. The stepped surface portion 53 is formed as an annular stepped surface extending in the circumferential direction of the second projecting portion 51, and a plurality of intermediate portions in the circumferential direction are located at the positions of the cutout portions 51C (for example, the four cutout portions 51C have four pieces. In this case, it is separated into four stepped surface portions 53). Further, as shown in FIG. 11, each step surface portion 53 is formed as a step surface that is slightly inclined with respect to a surface perpendicular to the axis of the valve body 37.

  Thus, also in the second embodiment configured as described above, the inlet-side passage 24 and the outlet-side passage are formed by the first protrusion 44 and the second protrusion 51 (the medium-diameter protrusion 51A and the small-diameter protrusion 51B). The pressure receiving area of the valve body 37 with respect to 25 can be changed in stages, and the same effect as in the first embodiment can be obtained. In particular, in the second embodiment, the second projecting portion 51 provided on the distal end side of the first projecting portion 44 is formed as a stepped projecting portion comprising a medium diameter projecting portion 51A and a small diameter projecting portion 51B. .

  For this reason, in addition to the annular stepped surface portion 52 formed between the medium-diameter projecting portion 51A and the first projecting portion 44 of the second projecting portion 51, it is formed between the medium-diameter projecting portion 51A and the small-diameter projecting portion 51B. The other stepped surface portion 53 can also receive the pressure in the inlet-side passage 24, and the pressure-receiving area of the valve body 37 with respect to the inlet-side passage 24 and the outlet-side passage 25 can be changed in three steps or more. In addition, the pressure range of the control pressure chamber 42 that can be used for controlling the middle opening region can be further widened.

  In the second embodiment, the case where the second projecting portion 51 has a two-stepped shape with the medium-diameter projecting portion 51A and the small-diameter projecting portion 51B has been described as an example. However, the present invention is not limited to this, and the second protrusion may be formed in a stepped shape having three or more steps. Further, as shown in FIG. 11, the stepped surface portion does not necessarily have to be constituted by a horizontal annular stepped surface so that the stepped surface portion 53 is formed as a stepped surface inclined obliquely.

  Further, in the second embodiment, the case where the notch 51C having a V-shaped cross section is formed in the second protrusion 51 has been described as an example. However, the shape of such a notch may be a shape that satisfies the flow rate (opening area) required when the poppet valve is opened, such as the second protrusion 45 described in the first embodiment. In addition, the same shape as the cutout portion 45A having a U-shaped cross section or another shape may be adopted. This is the same for the first embodiment.

  Further, in the first embodiment, a case where each notch 45A is formed as a slit groove extending in the radial direction between the inner peripheral surface and the outer peripheral surface of the second protrusion 45 will be described as an example. did. However, in the present invention, for example, in the range D shown in FIG. 9, the lift amount change of the valve element 37 with respect to the pressure change in the control pressure chamber 42 is reduced, so that the intermediate opening region (range D) is not affected. Each notch 45A of the second protrusion 45 may be formed to extend in the axial direction (upward in FIG. 4) to the position of the first protrusion 44.

  In each of the above-described embodiments, the poppet valve 36 that adjusts the flow rate of the pressure oil supplied and discharged from the arm control valve 18 toward the arm cylinder 9 has been described as an example. However, the present invention is not limited to this. For example, the present invention may be applied to a poppet valve for adjusting the flow rate of pressure oil supplied to and discharged from the boom control valve 16 to the boom cylinder 8. The present invention can also be applied to a poppet valve in which pressure oil is supplied and discharged through a directional control valve.

  Furthermore, the poppet valve according to the present invention only needs to be configured to variably control the flow rate of the fluid from a small flow rate to a large flow rate in accordance with the lift amount of the valve body. For example, the poppet valve is applicable to construction machines such as hydraulic excavators. However, the present invention is not limited, and can be applied to a wide range of poppet valves.

4 Working device 5 Boom 6 Arm 7 Bucket (Working tool)
8 Boom cylinder 9 Arm cylinder 10 Bucket cylinder 11 Hydraulic pump 12 Tank 13 Pump line 14 Center bypass line 15 Tank line 16 Boom control valve (direction control valve)
18 Arm control valve (directional control valve)
20 Relief valve 21 Control valve device 22 Valve casing (housing)
23 Spool sliding hole 24 Inlet side passage (first flow path)
24A Communication hole 25 Outlet side passage (second flow path)
26 Seat 27 Valve body sliding hole 29 Spool 34 Valve block (housing)
35 Pressure regulating valve 36 Poppet valve 37 Valve body 38 Valve member 38D Valve portion 38E Cylindrical protrusion 38F Valve seat 38G Stepped hole 40 Check valve body 42 Control pressure chamber 43 Valve spring 44 First protrusion 45, 51 Second Protruding part 45A, 51C Notch part 46, 52 Stepped surface part L Protruding length δ Radial gap (Difference in radial dimension)

Claims (3)

A housing having a first flow path and a second flow path communicating with each other via a communication hole, wherein a taper-shaped sheet portion is provided at an intersection of the second flow path with the communication hole;
An annular valve portion that is provided in the housing so as to advance and retreat from the second flow path side into the communication hole, and a cylinder in which the front end side protrudes toward the communication hole from the valve portion. A valve body having a protruding part;
A control pressure chamber formed between the housing and the valve body, to which a control pressure for variably controlling the lift amount of the valve body is supplied from the outside;
A valve spring provided in the control pressure chamber and biasing the valve body toward the seat portion in a valve closing direction;
The valve body changes an opening area of the communication hole between the first flow path and the second flow path according to the lift amount, and between the first flow path and the second flow path. In a poppet valve that controls the flow rate of flowing fluid,
The cylindrical protrusion of the valve body is
A first protrusion formed in a cylindrical shape from the position of the valve portion toward the inside of the communication hole and having a diameter smaller than the diameter of the communication hole;
A second projecting portion projecting in a cylindrical shape from the tip of the first projecting portion into the communication hole and having a smaller diameter than the first projecting portion by a predetermined dimension;
The poppet valve characterized in that the first projecting portion and the second projecting portion change the pressure receiving area of the valve body with respect to the first flow path and the second flow path in a stepwise manner.   2. The poppet valve according to claim 1, wherein a protrusion length of the second protrusion is formed to be larger than a difference in radial dimension between the first protrusion and the second protrusion.   The second projecting portion is provided with a plurality of notched portions formed by notching a front end side end surface thereof and communicating between an inner peripheral surface and an outer peripheral surface of the second projecting portion in a radial direction. The poppet valve according to 1 or 2.

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