Poppet valve and poppet valve device having the same

Abstract

This poppet valve comprises: a housing including a valve passage having a first passage portion and a second passage portion, a valve seat interposed between the first passage portion and the second passage portion, and a valve hole having a back pressure chamber to which an upstream pressure of the valve passage is guided; and a valve member that is accommodated in the valve hole so as to be slidable between a closed position in which the valve member is seated on the valve seat to close the valve passage and an open position in which the valve member opens the valve passage to an opening degree corresponding to a stroke amount, and that strokes depending on a back pressure of the back pressure chamber. The valve member includes: a valve body that has, on its tip side, a valve portion seated on the valve seat and that is slidably installed in the valve hole; and a cylindrical valve head portion protruding from the valve portion into the first passage portion. The valve head portion has a plurality of notches penetrating the valve head portion in the inward and outward direction, and a sliding portion in which the plurality of notches are formed. The sliding portion is slidably accommodated in the first passage portion.

Description

Poppet valve and poppet valve device including same

[0001] The present disclosure relates to a poppet valve that adjusts the opening degree of a valve passage, and a poppet valve device including the same.

[0002] A known example of a poppet valve that adjusts the opening degree of a valve passage is the flow control valve disclosed in Patent Document 1. The flow control valve of Patent Document 1 includes a valve element slidably mounted in a housing. The valve element closes the inlet-side passage and the outlet-side passage by seating a valve portion on a valve seat. On the other hand, the valve element opens the inlet-side passage and the outlet-side passage by moving the valve portion away from the valve seat, and also opens the valve passage by an opening degree corresponding to the stroke amount.

[0003] Japanese Patent Application Laid-Open No. 2022-166300

[0004] The flow control valve of Patent Document 1 has a cylindrical protrusion, or so-called valve head, on the tip side of the valve disc. The valve head protrudes into the inlet-side passage. A circumferentially extending annular groove is formed on the outer peripheral surface of the valve head adjacent to the tip side of the valve section. A fixed orifice is formed in the annular groove. Therefore, in the flow control valve, the inlet-side passage and the outlet-side passage communicate with each other via the fixed orifice and the annular groove immediately after the valve section leaves the valve seat. As a result, the opening area between the inlet-side passage and the outlet-side passage, i.e., the opening area of ​​the valve passage, increases rapidly immediately after the valve section leaves the valve seat. This results in a rapid increase in the flow of hydraulic fluid immediately after the valve section leaves the valve seat. On the other hand, a poppet valve is desired to be able to control flow rates over a smaller flow rate range. To enable flow rate control over a small flow rate range in a poppet valve, it is necessary to suppress the rapid increase in the opening area of ​​the valve passage immediately after the valve disc leaves the valve seat.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a poppet valve that can suppress a sudden increase in the opening area of ​​the valve passage immediately after the valve body leaves the valve seat.

[0006] The poppet valve of the present invention comprises: a housing including a valve passage having a first passage portion and a second passage portion; a valve seat interposed between the first passage portion and the second passage portion; and a valve hole having a back pressure chamber to which upstream pressure of the valve passage is directed; and a valve disc accommodated in the valve hole so as to be slidable between a closed position where it seats on the valve seat to close the valve passage and an open position where it opens the valve passage by an opening degree corresponding to a stroke amount, the valve disc including a valve body having a valve portion at a tip end thereof that seats on the valve seat and is slidably provided in the valve hole; and a cylindrical valve head portion protruding from the valve portion into the first passage portion, the valve head portion having a plurality of notches penetrating inward and outward directions through the valve head portion and a sliding portion in which the plurality of notches are formed, the sliding portion being slidably accommodated in the first passage portion.

[0007] According to the present invention, the valve head is cylindrical and protrudes into the first passage portion. The valve head has a plurality of notches penetrating the valve head in an inward-outward direction and a sliding portion in which the plurality of notches are formed. The sliding portion is slidably housed in the first passage portion. This reduces the gap between the first passage portion and the sliding portion. This prevents a sudden increase in the opening area of ​​the valve passage immediately after the valve portion leaves the valve seat, and allows the opening area of ​​the valve passage to be controlled in accordance with the opening degree of the notches. This allows the opening degree of the valve passage to be controlled at a smaller opening degree.

[0008] The poppet valve device of the present invention comprises the above-described poppet valve and a spool valve that discharges pressurized liquid from the back pressure chamber, the spool valve adjusting the back pressure by stroking to discharge pressurized liquid from the back pressure chamber, and the poppet valve adjusting the opening of the valve passage in accordance with the back pressure.

[0009] According to the present invention, a poppet valve device having the above-described functions can be realized.

[0010] According to the present invention, it is possible to suppress a sudden increase in the opening area of ​​the valve passage immediately after the valve disc leaves the valve seat.

[0011] The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings.

[0012] Fig. 1 is a cross-sectional view showing a poppet valve device of the present embodiment. Fig. 2 is an enlarged cross-sectional view showing a poppet valve provided in the poppet valve device of Fig. 1. Fig. 2 is an enlarged cross-sectional view showing a state in which the main valve body is at a full stroke in the poppet valve. Fig. 3 is an enlarged perspective view showing a valve head portion of the poppet valve of Fig. 2. Fig. 3 is an enlarged cross-sectional view showing an enlarged portion near the valve head portion of the poppet valve of Fig. 2. Fig. 4 is an enlarged cross-sectional view showing a poppet valve provided in a poppet valve device of a second embodiment. Fig. 5 is an enlarged cross-sectional view showing a poppet valve provided in a poppet valve device of a third embodiment. Fig. 6 is an enlarged perspective view showing a valve body of a poppet valve provided in a poppet valve device of another embodiment. Fig. 7 is an enlarged perspective view showing a valve body of a poppet valve provided in a poppet valve device of yet another embodiment.

[0013] Hereinafter, poppet valve devices 1, 1A, and 1B and poppet valves 2, 2A, and 2B provided therein according to first to third embodiments of the present disclosure will be described with reference to the drawings. Note that the concepts of directions used in the following description are used for convenience of explanation and do not limit the orientation of the configuration of the present invention to those directions. Furthermore, the poppet valve devices 1, 1A, and 1B and poppet valves 2, 2A, and 2B described below are merely one embodiment of the present disclosure. Therefore, the present disclosure is not limited to the embodiments, and additions, deletions, and modifications are possible within the scope of the invention.

[0014] <First embodiment> [Poppet valve device] The poppet valve device 1 shown in Fig. 1 controls the flow rate of hydraulic fluid in accordance with an energization state (e.g., current or voltage). The poppet valve device 1 is provided in a construction machine such as a shovel. The poppet valve device 1 controls the flow rate of hydraulic fluid flowing to a hydraulic actuator provided in the construction machine in accordance with an energization state. The poppet valve device 1 includes, for example, a poppet valve 2 and an electric spool valve 4.

[0015] 2 has a housing 10, as will be described in detail later, and adjusts the degree of opening of a valve passage 12 formed in the housing 10. Explained in more detail, the poppet valve 2 adjusts the degree of opening of the valve passage 12 in response to the back pressure, as will be described in detail later. As a result, the poppet valve 2 allows working fluid to flow at a flow rate corresponding to the back pressure. Explained in even more detail, the poppet valve 2 includes a main valve element 14, a check valve element 15, and a main valve spring member 16.

[0016] The housing 10 includes a valve hole 11, a valve passage 12, and a valve seat 13. The valve hole 11 is a bottomed hole extending along a predetermined axis L1. A main valve element 14, which will be described in detail later, is housed in the valve hole 11. The valve passage 12 is formed in the housing 10 so as to interpose the valve hole 11 therebetween. More specifically, the valve passage 12 includes a first passage portion 12a and a second passage portion 12b. The first passage portion 12a has a valve port 11a that opens at the bottom surface of the valve hole 11 and is connected to the valve hole 11 via the valve port 11a. In this embodiment, the first passage portion 12a extends from the valve port 11a in a first direction. The first direction is the direction in which the axis L1 of the valve hole 11 extends. The valve seat 13 is interposed between the first passage portion 12a and the second passage portion 12b. In this embodiment, the valve seat 13 is formed on the bottom surface of the valve hole 11 so as to surround the valve port 11a. On the other hand, the second passage portion 12b opens on the inner circumferential surface of the bottom portion of the valve hole 11 and is connected to the valve hole 11. In this way, the first passage portion 12a and the second passage portion 12b are each connected to the valve hole 11 and are connected to each other via the valve hole 11. In this embodiment, in the valve passage 12, working fluid flows from the first passage portion 12a through the valve hole 11 to the second passage portion 12b.

[0017] The valve hole 11 also has a back pressure chamber 11c. The upstream pressure of the valve passage 12, i.e., the hydraulic pressure of the first passage portion 12a in this embodiment, is introduced into the back pressure chamber 11c. More specifically, the back pressure chamber 11c is a space formed in the valve hole 11 by the main valve element 14 (described in detail below), and is located on the opposite side of the valve orifice 11a in the first direction in the valve hole 11. That is, the valve orifice 11a is located on one side of the valve hole 11 in the first direction, and the back pressure chamber 11c is located on the other side in the first direction. The valve hole 11 also has an annular passage portion 11d. The annular passage portion 11d is an annular groove recessed radially outward in the axially intermediate portion of the valve hole 11. The back pressure chamber 11c is connected to the first passage portion 12a via a feedback flow path 14a (described in detail below) and the annular passage portion 11d.

[0018] As shown in FIG. 2 , a main valve element 14, which is an example of a valve element, is slidably disposed in the valve hole 11. More specifically, the main valve element 14 is slidably disposed in the valve hole 11 in a first direction. Even more specifically, the main valve element 14 is slidably disposed in the valve hole 11 between a closed position and an open position. In the closed position, the main valve element 14 is seated on the valve seat 13 to close the valve port 11a (i.e., close the valve passage 12). In the open position, the main valve element 14 is lifted from the valve seat 13 to open the valve port 11a (i.e., open the valve passage 12) (see FIG. 3 ). In the open position, the valve port 11a opens to an opening degree corresponding to the stroke of the main valve element 14. In this way, the main valve element 14 opens and closes the valve port 11a by sliding in the first direction, and adjusts the opening degree of the valve passage 12 depending on its position. More specifically, the main valve element 14 includes a valve body 17 and a valve head 18 .

[0019] The valve body 17 is slidably disposed in the valve hole 11. The valve body 17 has a valve portion 17a at its tip end. The valve portion 17a seats on the valve seat 13 and closes the valve port 11a by sitting on it. In this embodiment, the valve portion 17a is formed in a tapered shape. However, the valve portion 17a does not necessarily have to be tapered and may be formed flat.

[0020] As shown in Figures 4 and 5, the valve head section 18 is cylindrical and protrudes into the first passage section 12a. More specifically, the valve head section 18 forms the tip end portion of the main valve element 14 and extends from the valve section 17a in one axial direction. Here, the axial direction refers to the direction in which the axis of the main valve element 14 extends, which is the same as the first direction in this embodiment. The valve head section 18 thus configured has a sliding section 18a and multiple notches 18b. More specifically, the valve head section 18 has a guided section 18c.

[0021] The sliding portion 18a is slidably accommodated in the first passage portion 12a. More specifically, the sliding portion 18a is annular, and in this embodiment, circular. The sliding portion 18a is accommodated in the first passage portion 12a with almost no gap between it and the first passage portion 12a over the entire circumferential direction. In this embodiment, a very small gap (i.e., a sliding gap) of, for example, 5 μm or more and 50 μm or less is formed between the sliding portion 18a and the first passage portion 12a. This prevents hydraulic fluid from flowing between the sliding portion 18a and the first passage portion 12a.

[0022] Multiple notches 18b are formed in the sliding portion 18a. In this embodiment, six notches 18b are formed in the sliding portion 18a at equal intervals in the circumferential direction. The number of notches 18b is not limited to six and may be five or less, or seven or more. The multiple notches 18b penetrate the valve head portion 18 inward and outward directions. Each of the notches 18b is, for example, a semicircular notch, and opens at the tip of the valve head portion 18. That is, the notches 18b are formed in an arc shape on the valve portion 17a side and open in one axial direction. Note that the shape of the notches 18b described above is merely an example, and other shapes such as a bow shape, an ellipse shape, or a U-shape may be used, as long as the valve portion side is arc-shaped. Furthermore, the notches 18b are arranged in the sliding portion 18a away from the valve portion 17a in one axial direction. However, the notch 18b may be disposed adjacent to the valve portion 17a in one side of the first direction.

[0023] The guided portion 18c is formed on the tip side of the sliding portion 18a in the valve head portion 18. More specifically, the guided portion 18c extends from the sliding portion 18a to one axial side. The guided portion 18c protrudes into the first passage portion 12a when the main valve element 14 is in a full-stroke state, where it is farthest from the valve seat 13. This prevents the tip portion of the main valve element 14 from slipping out of the first passage portion 12a even during a full stroke. A gap d is provided between the guided portion 18c and the first passage portion 12a. The gap d is, for example, 0.3 mm or more and 0.5 mm or less. That is, the guided portion 18c is spaced radially inward from the first passage portion 12a. More specifically, the outer peripheral surface of the guided portion 18c has a radius of curvature smaller than the outer diameter of the sliding portion 18a. Therefore, the outer peripheral surface of the valve head portion 18 is formed in a stepped shape with the guided portion 18c having a smaller diameter than the sliding portion 18a.

[0024] Furthermore, in this embodiment, the guided portion 18c is configured as follows. That is, the guided portion 18c has a plurality of legs 18d. The legs 18d are formed at intervals from one another in the circumferential direction on the tip side of the sliding portion 18a. More specifically, the legs 18d are formed between two adjacent notches 18b on the tip side of the sliding portion 18a. In this embodiment, four legs 18d are formed on the tip side of the sliding portion 18a. Two of the four legs 18d are positioned 180 degrees apart from one another. That is, the sliding portion 18a has a formed portion 18e where legs 18d are formed on the tip side, and a non-formed portion 18f where no legs 18d are formed. In this embodiment, the sliding portion 18a has four formed portions 18e and two non-formed portions 18f. The formed portion 18e and the non-formed portion 18f are both located between two adjacent notches 18b, and the two non-formed portions 18f are positioned 180 degrees apart from each other. As a result, the main valve body 14, thanks to the legs 18d, is stably guided even after the sliding portion 18a is released from the first passage portion 12a. Furthermore, in the non-formed portion 18f of the main valve body 14, a larger opening is formed between two adjacent legs 18d. More specifically, in the non-formed portion 18f, an opening having a width approximately equal to the combined width of the two notches 18b and the non-formed portion 18f is formed between the two adjacent legs 18d. Therefore, a larger flow rate of hydraulic fluid can flow through the opening in the guided portion 18c.

[0025] As shown in FIG. 2 , the main valve element 14 forms a back pressure chamber 11c in the valve hole 11. More specifically, the back pressure chamber 11c is formed on the opposite side of the valve orifice 11a in the first direction across the main valve element 14 in the valve hole 11. As described above, the upstream pressure of the valve passage 12 is guided to the back pressure chamber 11c. The main valve element 14 receives back pressure, which is the hydraulic pressure of the back pressure chamber 11c, in one first direction (i.e., the closing direction, which closes the valve passage 12). More specifically, the main valve element 14 includes a feedback flow path 14a in the back pressure chamber 11c, and the upstream pressure of the valve passage 12 is guided to the back pressure chamber 11c via the feedback flow path 14a and the annular passage portion 11d. That is, the feedback flow path 14a guides hydraulic fluid from the first passage portion 12a to the back pressure chamber 11c. More specifically, the feedback passage 14a has an internal passage portion 14b and a plurality of side notches 14c.

[0026] The internal passage 14b is formed inside the main valve body 14 and is connected to the first passage portion 12a. More specifically, the internal passage 14b is formed in the valve body 17. The internal passage 14b opens to an inner bore 18g of the valve head portion 18 at the tip of the valve body 17. As a result, the internal passage 14b is connected to the first passage portion 12a via the inner bore 18g of the valve head portion 18, and working fluid is guided to the internal passage 14b via the inner bore 18g. A plurality of side notches 14c are arranged at intervals in the middle portion of the outer peripheral surface of the main valve body 14 and are connected to the internal passage 14b. More specifically, the plurality of side notches 14c are each connected to the internal passage 14b via a branch passage 14d extending radially. Each of the side notches 14c is disposed corresponding to the annular passage portion 11d, and is connected to the back pressure chamber 11c via the annular passage portion 11d.

[0027] The check valve element 15 opens and closes the feedback flow path 14a. More specifically, the check valve element 15 is slidably disposed within the main valve element 14. A check valve seat 14e is formed in the internal passage portion 14b. The check valve seat 14e is located in the internal passage portion 14b closer to the tip (i.e., upstream) of each of the branch passage portions 14d. The check valve element 15 can be seated on the check valve seat 14e. The check valve element 15 closes the feedback flow path 14a by seating on the check valve seat 14e (see FIG. 2), and opens the feedback flow path 14a by moving away from the check valve seat 14e (see FIG. 3). The check valve element 15 receives hydraulic pressure from the hydraulic fluid flowing from the first passage portion 12a to the back pressure chamber 11c and is urged toward the check valve seat 14e against this hydraulic pressure. As a result, the check valve body 15 allows the flow of hydraulic fluid from the first passage portion 12a to the back pressure chamber 11c, and prevents the flow in the reverse direction.

[0028] The main valve spring member 16 biases the main valve element 14 toward the closed position. More specifically, the main valve spring member 16 is a compression coil spring. The main valve spring member 16 is accommodated in a compressed state in the back pressure chamber 11c. In this embodiment, the back pressure chamber 11c is blocked by a housing 21, which will be described in detail later. The main valve spring member 16 abuts against the housing 21 and the main valve element 14, and is accommodated in the back pressure chamber 11c in a compressed state. As a result, the main valve element 14 is biased in the closing direction, i.e., toward the valve seat 13.

[0029] [Motorized Spool Valve] The motorized spool valve 4 is provided in a housing 10 as shown in FIG. 1 . More specifically, the motorized spool valve 4 is provided in the housing 10 so as to close the valve hole 11 (more specifically, the back pressure chamber 11c). The motorized spool valve 4 is electrically conductive, and its opening degree is adjusted depending on the state of conduction. In this embodiment, the motorized spool valve 4 discharges pressurized fluid from the back pressure chamber 11c. The opening degree of the motorized spool valve 4 is also variable depending on the state of conduction, and by changing the opening degree, the back pressure in the back pressure chamber 11c is adjusted. The motorized spool valve 4 configured in this manner includes a housing 21, a spool 22, an electric device 23, and a spring member 24.

[0030] The housing 21 is provided in the housing 10. More specifically, the housing 21 is provided in the housing 10 so as to close the valve hole 11. As shown in FIG. 1 , the housing 21 has a spool hole 31, an inlet-side flow path 32, and an outlet-side flow path 33.

[0031] The spool hole 31 slidably accommodates the spool 22. In this embodiment, the spool hole 31 extends in the second direction in the housing 21. The second direction is, for example, a direction perpendicular to the first direction. More specifically, the spool hole 31 penetrates the housing 21 in the second direction. One side of the spool hole 31 in the second direction is blocked by the spring receiving portion 25, and the other side in the second direction is blocked by the electric device 23. The inlet-side flow path 32 and the outlet-side flow path 33 are each connected to the spool hole 31. The inlet-side flow path 32 is connected to the back pressure chamber 11c, connecting the spool hole 31 and the back pressure chamber 11c. On the other hand, the outlet-side flow path 33 is connected to the second passage portion 12b of the valve passage 12. More specifically, the housing 10 has a connecting passage 10a, and the outlet-side flow passage 33 is connected to the second passage portion 12b via the connecting passage 10a.

[0032] The spool 22 is slidably inserted into the spool hole 31. More specifically, the spool 22 strokes to open and close the gap between the inlet-side flow path 32 and the outlet-side flow path 33. When the spool 22 strokes, it also adjusts the gap between the inlet-side flow path 32 and the outlet-side flow path 33 to an opening degree that corresponds to the stroke amount.

[0033] The electric device 23 strokes the spool 22. More specifically, the electric device 23 is attached to the housing 21 so as to close the opening on the other side of the spool hole 31 in the second direction. The electric device 23 is an electrically driven linear motion device that applies a load to the spool 22 according to the energized state, thereby stroking the spool 22 in one direction in the second direction. The electric device 23 is, for example, a linear motion solenoid or a ball screw motor. In this embodiment, the electric device 23 is a linear motion solenoid.

[0034] The spring member 24 biases the spool 22 in the other second direction. More specifically, the spring member 24 biases the spool 22 against the load from the electric device 23. The spring member 24 is, for example, a compression coil spring. The spring member 24 is housed in a compressed state on one side of the spool hole 31 in the second direction. As a result, the spool 22 is biased in the other second direction by the spring member 24.

[0035] [Operation of the Poppet Valve Device] When the electric spool valve 4 is energized, the poppet valve device 1 operates as follows. That is, in the electric spool valve 4, the spool 22 strokes in one direction in the second direction, opening the gap between the inlet-side flow path 32 and the outlet-side flow path 33. This causes pressurized fluid in the back pressure chamber 11c of the poppet valve 2 to flow from the inlet-side flow path 32 to the outlet-side flow path 33 and then to be discharged to the second passage portion 12b of the valve passage 12 via the connecting passage 10a. Meanwhile, in the poppet valve 2, the discharge of pressurized fluid from the back pressure chamber 11c opens the feedback passage 14a, which had been closed by the check valve element 15 (see FIG. 3). Then, working fluid is guided from the first passage portion 12a of the valve passage 12 to the back pressure chamber 11c via the feedback passage 14a, the annular passage portion 11d, and the gap between the main valve element 14 and the valve bore 11 (see the bold line in FIG. 3). At this time, a pressure loss occurs in the side notch 14c, so the pressure in the back pressure chamber 11c, i.e., the back pressure, is reduced, and the main valve element 14 lifts to a position where the back pressure, the upstream pressure of the valve passage 12, and the biasing force of the main valve spring member 16 are balanced.

[0036] The back pressure is a pressure that corresponds to the ratio of the opening area of ​​the side notch 14c to the opening degree between the inlet-side flow path 32 and the outlet-side flow path 33. Therefore, the main valve element 14 lifts by an amount that corresponds to the ratio of the opening area of ​​the side notch 14c to the opening degree between the inlet-side flow path 32 and the outlet-side flow path 33. Since the opening degree between the inlet-side flow path 32 and the outlet-side flow path 33 is controlled according to the energized state of the electric spool valve 4, the main valve element 14 lifts by an amount that corresponds to the energized state of the electric spool valve 4. Therefore, in the poppet valve device 1, the flow rate through the valve passage 12 can be controlled, for example, according to the characteristics of the main valve element opening area relative to the lift amount.

[0037] More specifically, when the electric spool valve 4 is energized and the main valve element 14 leaves the valve seat 13, the poppet valve 2 operates as follows. That is, in the poppet valve 2, the valve head 18 leaves the valve seat 13 while sliding the sliding portion 18a along the first passage portion 12a. Furthermore, multiple notches 18b are formed in the sliding portion 18a. Therefore, in the poppet valve 2, immediately after the main valve element 14 leaves the valve seat 13 (more specifically, before the notches 18b reach the valve orifice 11a), the opening area of ​​the valve passage 12 can be kept approximately the cross-sectional area of ​​the sliding gap, i.e., very small. This prevents the opening area of ​​the valve passage 12 from increasing rapidly immediately after the poppet valve 2 leaves the valve seat 13.

[0038] Furthermore, after the notches 18b reach the valve port 11a, the valve passage 12 opens with an opening area corresponding to the exposed area, which is the area of ​​the portion of the multiple notches 18b that is exposed from the valve port 11a to the valve hole 11. More specifically, in the poppet valve 2, the exposed area of ​​the multiple notches 18b increases according to the stroke amount of the main valve element 14. Therefore, in the poppet valve 2, the valve passage 12 can be opened with an opening area corresponding to the stroke amount of the main valve element 14. As a result, the poppet valve device 1 can flow hydraulic fluid from the first passage portion 12a to the second passage portion 12b at a flow rate that corresponds to the energized state of the electric spool valve 4.

[0039] Furthermore, in the poppet valve 2, the multiple notches 18b are formed in a semicircular shape in this embodiment. Therefore, after reaching the valve port 11a, the shape of the notches 18b exposed to the valve hole 11 is arched, allowing the exposed area of ​​the multiple notches 18b to gradually increase. This also prevents the opening area of ​​the valve passage 12 from increasing suddenly immediately after unseating. On the other hand, after the sliding portion 18a moves from the valve port 11a to the valve hole 11, the non-formed portion 18f ensures a larger opening area in the valve passage 12. This reduces pressure loss that occurs in the working fluid when a large flow rate of working fluid flows through the valve passage 12.

[0040] Furthermore, in the poppet valve 2, the guided portion 18c of the valve head portion 18 is positioned within the first passage portion 12a even when the main valve element 14 is at its full stroke. This prevents the main valve element 14 from slipping out of the first passage portion 12a. This prevents the main valve element 14 from being unable to seat on the valve seat 13 and close the valve passage 12. In particular, in this embodiment, the guided portion 18c has four legs 18d, and two of the four legs 18d are positioned 180 degrees apart. This allows the main valve element 14 to move along the first passage portion 12a by the four legs 18d.

[0041] In the poppet valve 2 of the first embodiment, the valve head portion 18 is cylindrical and protrudes into the first passage portion 12a. The valve head portion 18 has a plurality of notches 18b penetrating the valve head portion 18 inward and outward directions and a sliding portion 18a in which the plurality of notches 18b are formed. The sliding portion 18a is slidably received in the first passage portion 12a. This reduces the gap between the first passage portion 12a and the sliding portion 18a. This prevents a sudden increase in the opening area of ​​the valve passage 12 immediately after the valve portion 17a leaves the valve seat 13, and allows the opening area of ​​the valve passage 12 to be controlled in accordance with the opening degree of the notches 18b. This allows the opening degree of the valve passage 12 to be controlled to a smaller opening degree.

[0042] Furthermore, in the poppet valve 2 of the first embodiment, the guided portion 18c protrudes into the first passage portion 12a when the main valve element 14 is in a full stroke state. Therefore, even when the main valve element 14 is in a full stroke state, the valve head portion 18 does not come out of the first passage portion 12a. As a result, the guided portion 18c is guided by the first passage portion 12a, allowing the main valve element 14 to seat on the valve seat 13 again. Therefore, it is possible to prevent the main valve element 14 from being unable to seat on the valve seat 13.

[0043] Furthermore, in the poppet valve 2 of the first embodiment, the sliding portion 18a has a formed portion 18e and a non-formed portion 18f. Therefore, a large opening can be formed between adjacent leg portions 18d in the non-formed portion 18f. This allows a larger flow rate of working fluid to flow through the opening between the leg portions 18d after the sliding portion 18a is separated from the first passage portion 12a. This reduces pressure loss of the working fluid.

[0044] Furthermore, in the poppet valve 2 of the first embodiment, a gap d is provided between the guided portion 18c and the first passage portion 12a. Therefore, after the sliding portion 18a is separated from the first passage portion 12a, hydraulic fluid can also flow between the guided portion 18c and the first passage portion 12a. This allows a larger amount of hydraulic fluid to flow, thereby reducing hydraulic fluid pressure loss. Furthermore, after the sliding portion 18a is separated from the first passage portion 12a, the sliding resistance of the main valve element 14 can be reduced, allowing the main valve element 14 to move smoothly. This improves controllability in the large flow rate range.

[0045] Furthermore, in the poppet valve 2 of the first embodiment, the portions of the plurality of notches 18b on the valve portion 17a side are formed in an arc shape. Therefore, as the notches 18b open, they open in an arc shape, making it easy to finely control the opening area of ​​the notches 18b. This allows the poppet valve 2 to control the flow rate in a finer flow rate range.

[0046] The poppet valve device 1 of the first embodiment can realize the poppet valve device 1 having the above-described functions.

[0047] 6 are similar in configuration to the poppet valve device 1 and the poppet valve 2 of the first embodiment. Therefore, the configurations of the poppet valve device 1A and the poppet valve 2A of the second embodiment will be mainly described with respect to differences from the poppet valve device 1A and the poppet valve 2 of the first embodiment, and the same components will be assigned the same reference numerals and description thereof will be omitted. The same applies to a third embodiment and the like described below.

[0048] The poppet valve device 1A of the second embodiment shown in FIG. 6 includes, for example, a housing 10, a poppet valve 2A, and an electric spool valve 4 (not shown). The poppet valve 2A includes a main valve element 14A, a check valve element 15, and a main valve spring member 16. The main valve element 14A includes a valve body 17 and a valve head portion 18A. The valve head portion 18A has a sliding portion 18a, a guided portion 18Ac, and multiple notches 18Ab. The guided portion 18Ac extends axially from the sliding portion 18a of the valve head portion 18 to one side and protrudes into the first passage portion 12a when the main valve element 14 is in a full-stroke state where it is farthest from the valve seat 13. In this embodiment, the guided portion 18Ac is cylindrical, similar to the sliding portion 18a. The multiple notches 18Ab are formed throughout the valve head portion 18. That is, the notch 18Ab is also formed in the guided portion 18Ac. The notch 18Ab is formed, for example, in a circular shape, and the side of the notch 18Ab facing the valve portion 17a is formed in an arc shape. In this embodiment, the notch 18Ab formed in the guided portion 18Ac has a smaller diameter than the notch 18Ab formed in the sliding portion 18a.

[0049] The poppet valve device 1A and the poppet valve 2A of the second embodiment have the same functions and effects as the poppet valve device 1 and the poppet valve 2 of the first embodiment.

[0050] 7 includes, for example, a housing 10, a poppet valve 2B, and an electric spool valve 4 (not shown). The poppet valve 2B includes a main valve element 14B, a check valve element 15, and a main valve spring member 16. The main valve element 14B includes a valve body 17 and a valve head portion 18B. The valve head portion 18B has a sliding portion 18a, a guided portion 18c, and a plurality of notches 18b, 18Bb.

[0051] Like the notches 18b in the first embodiment, the first notches 18b are formed, for example, semicircularly and spaced apart from the valve portion 17a toward the distal end. Like the first notches 18b, the second notches 18Bb penetrate the valve head 18 inward and outward directions. The second notches 18Bb are formed, for example, circularly. More specifically, the second notches 18Bb are disposed between the first notches 18b and the valve portion 17a in the sliding portion 18a and spaced apart from each other in the circumferential direction. In this embodiment, four notches 18b, 18Bb are formed in the sliding portion 18a, and are alternately arranged with a circumferential space between them. Furthermore, between two adjacent first notches 18b on the distal end of the sliding portion 18a, formed portions 18e and non-formed portions 18f are alternately arranged, and guided portions 18c are formed in the formed portions 18e. The outer circumferential surface of the guided portion 18c is tapered toward the tip end, i.e., the outer circumferential surface of the leg portion 18d is inclined radially inward toward the tip end.

[0052] In the poppet valve 2B of the third embodiment, the outer peripheral surface of the guided portion 18c is inclined radially inward. This allows the opening area between the guided portion 18c and the first passage portion 12a to gradually increase. This prevents a sudden increase in the opening area after the sliding portion 18a separates from the first passage portion 12a.

[0053] In addition, the poppet valve device 1B and the poppet valve 2B of the third embodiment have the same functions and effects as the poppet valve device 1 and the poppet valve 2 of the first embodiment.

[0054] <Other Embodiments> In the poppet valve devices 1, 1A, and 1B of the present embodiment, the working fluid flows from the first passage portion 12a to the second passage portion 12b in the valve passage 12, but it may also flow from the second passage portion 12b to the first passage portion 12a. In this case, the second passage portion 12b is the upstream side of the valve passage 12, and the feedback flow path 14a of the main valve element 14 is connected to the second passage portion 12b. In addition, in the main valve element 14B of the poppet valve 2B, circular second notches 18Bb are arranged between adjacent notches 18b, but the second notches 18Bb may be formed in a vertically elongated rounded rectangular shape extending from the sliding portion 18a to the leg portions 18d, as in the valve head portion 18C of the main valve element 14C shown in Figure 8. Also, as in the valve head portion 18D of the main valve body 14D shown in Figure 9, two second notches 18Bb may be arranged between the first notches 18b, and a third notch 18Db may be formed in the leg portion 18d.

[0055] Furthermore, in the poppet valves 2, 2A, and 2B of this embodiment, the sliding portion 18a is connected to the valve portion 17a, but the sliding portion 18a may be formed separate from the valve portion 17a. In this case, the main valve element 14 is configured so that, in the closed position, no working fluid is guided between the sliding portion 18a and the valve portion 17a. In the main valve elements 14, 14A, and 14B, the leg portion 18d is separated from the first passage portion 12a, but the leg portion 18d may slide in the first passage portion 12a. Furthermore, the valve head portions 18, 18A, and 18B of the main valve elements 14, 14A, and 14B do not necessarily have to have the guided portions 18c and 18Ac. Furthermore, the sliding portion 18a does not necessarily have to have the non-formed portion 18f.

[0056] Illustrative Embodiment A poppet valve according to a first aspect includes: a housing including a valve passage having a first passage portion and a second passage portion; a valve seat interposed between the first passage portion and the second passage portion; and a valve hole having a back pressure chamber to which upstream pressure of the valve passage is directed; and a valve disc accommodated in the valve hole so as to be slidable between a closed position where the valve passage is seated on the valve seat and closed, and an open position where the valve passage is opened by an opening degree corresponding to a stroke amount, the valve disc including a valve body having a valve portion at a tip end thereof seated on the valve seat and slidably provided in the valve hole; and a cylindrical valve head portion protruding from the valve portion into the first passage portion, the valve head portion having a plurality of notches penetrating inward and outward directions through the valve head portion and a sliding portion in which the plurality of notches are formed, the sliding portion being slidably accommodated in the first passage portion.

[0057] According to the above aspect, the valve head is cylindrical and protrudes into the first passage portion. The valve head has a plurality of notches penetrating the valve head in an inward-outward direction and a sliding portion in which the plurality of notches are formed. The sliding portion is slidably housed in the first passage portion. This reduces the gap between the first passage portion and the sliding portion. This prevents a sudden increase in the opening area of ​​the valve passage immediately after the valve portion leaves the valve seat, and allows the opening area of ​​the valve passage to be controlled in accordance with the opening degree of the notches. This allows the opening degree of the valve passage to be controlled at a smaller opening degree.

[0058] In the poppet valve of the second aspect, in the poppet valve of the first aspect, the valve head further has a guided portion formed on the tip side of the sliding portion, and the guided portion protrudes into the first passage portion in a full stroke state in which the valve body is farthest from the valve seat.

[0059] According to the above aspect, the guided portion protrudes into the first passage portion when the valve element is at its full stroke. Therefore, even when the valve element is at its full stroke, the valve head portion does not come out of the first passage portion. As a result, the guided portion is guided by the first passage portion, allowing the main valve element to seat on the valve seat again. Therefore, it is possible to prevent the valve element from failing to seat on the valve seat.

[0060] In a poppet valve of a third aspect, in the poppet valve of the second aspect, the guided portion has a plurality of legs formed in the sliding portion, the plurality of notches are arranged at intervals from one another in the sliding portion, and the sliding portion has formed portions where the legs are formed between adjacent notches, and non-formed portions where the legs are not formed.

[0061] According to the above aspect, the sliding portion has a formed portion and a non-formed portion. Therefore, a large opening can be formed between adjacent leg portions in the non-formed portion. This allows a larger flow rate of hydraulic fluid to flow through the opening between the leg portions after the sliding portion separates from the first passage portion. Therefore, pressure loss of the hydraulic fluid can be reduced.

[0062] In a fourth aspect of the poppet valve, in the poppet valve of the second or third aspect, a gap is provided between the guided portion and the first passage portion.

[0063] According to the above aspect, a gap is provided between the guided portion and the first passage portion. Therefore, after the sliding portion is released from the first passage portion, hydraulic fluid can also flow between the guided portion and the first passage portion. This allows a larger amount of hydraulic fluid to flow, thereby reducing pressure loss of the hydraulic fluid. Furthermore, after the sliding portion is released from the first passage portion, the sliding resistance of the valve element can be reduced, allowing the valve element to move smoothly. This improves controllability in the large flow rate range.

[0064] In a poppet valve according to a fifth aspect, in the poppet valve according to the fourth aspect, the outer peripheral surface of the guided portion is inclined radially inward toward the tip end side.

[0065] According to the above aspect, the outer peripheral surface of the guided portion is inclined radially inward. Therefore, the opening area between the guided portion and the first passage portion can be gradually increased. This makes it possible to prevent a sudden increase in the opening area after the sliding portion separates from the first passage portion.

[0066] In a sixth aspect of the poppet valve, in the poppet valve of any one of the first to fifth aspects, the plurality of notches are formed such that the valve portion side portions thereof are arc-shaped.

[0067] According to the above aspect, the plurality of notches are formed in an arc-shaped configuration on the valve portion side. Therefore, when the valve body separates from the valve seat and the notches open, the notches open in an arc-shaped configuration, which facilitates fine control of the opening area of ​​the notches. This allows the poppet valve to control the flow rate over a smaller flow rate range.

[0068] A poppet valve device in a seventh aspect includes any one of the first to sixth poppet valves and a spool valve that discharges pressurized liquid from the back pressure chamber, the spool valve adjusting the back pressure by stroking to discharge pressurized liquid from the back pressure chamber, and the poppet valve adjusting the opening of the valve passage in accordance with the back pressure.

[0069] According to the above aspect, it is possible to realize a poppet valve device having the above-described functions.

[0070] From the above description, many modifications and other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the above description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present invention. Details of the structure and / or function thereof may be substantially changed without departing from the spirit of the present invention.

Claims

1. A poppet valve comprising: a housing including a valve passage having a first passage portion and a second passage portion, a valve seat interposed between the first passage portion and the second passage portion, and a valve orifice having a back pressure chamber to which upstream pressure of the valve passage is directed; and a valve disc accommodated in the valve orifice so as to be slidable between a closed position where it seats on the valve seat to close the valve passage and an open position where it opens the valve passage by an amount corresponding to its stroke, the valve disc including a valve body having a valve portion at its tip end that seats on the valve seat and is slidably disposed in the valve orifice, and a cylindrical valve head portion that protrudes from the valve portion into the first passage portion, the valve head portion having a plurality of notches penetrating inward and outward directions through the valve head portion and a sliding portion in which the plurality of notches are formed, the sliding portion being slidably accommodated in the first passage portion.

2. A poppet valve as set forth in claim 1, wherein the valve head further has a guided portion formed on the tip side of the sliding portion, and the guided portion protrudes into the first passage portion when the valve element is in a full stroke state where it is farthest from the valve seat.

3. A poppet valve as set forth in claim 2, wherein the guided portion has a plurality of legs formed in the sliding portion, the plurality of notches are arranged at intervals from one another in the sliding portion, and the sliding portion has formed portions where the legs are formed between adjacent notches, and non-formed portions where the legs are not formed.

4. The poppet valve according to claim 2, wherein a gap is provided between the guided portion and the first passage portion.

5. A poppet valve as set forth in claim 4, wherein the outer peripheral surface of said guided portion is inclined radially inward toward the tip side.

6. The poppet valve according to claim 1, wherein the plurality of notches are formed in an arc shape on the valve portion side.

7. A poppet valve device comprising: the poppet valve according to claim 1; and a spool valve that discharges pressurized liquid from the back pressure chamber, wherein the spool valve adjusts the back pressure by stroking to discharge the pressurized liquid from the back pressure chamber, and the poppet valve adjusts the opening of the valve passage in accordance with the back pressure.

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