JP2005076765A - Check valve and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inhibit the fall-down of a poppet 20 while preventing the blockage of a clearance between an outer peripheral face of a cylindrical part 21 of the poppet 20 and an inner peripheral face of a housing 13 by contaminants and the like. <P>SOLUTION: This check valve 12 has the housing 13 having a flow channel F4, and the approximately cylindrical bottomed poppet 20 accommodated movably in the longitudinal direction L1 of the flow channel 4 and having a cylindrical part 21 and a bottom part 22. A seating face 23 capable of being seated on a seating surface 14 of the housing 13 is formed on the bottom part 22. A plurality of projecting parts 27 projecting radially outwardly, are formed on an outer periphery of the cylindrical part 21 intermittently in the circumferential direction and the axial direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a check valve suitably used for, for example, a vehicle power steering apparatus and a method for manufacturing the check valve.

  A vehicle power steering device that applies a steering assist force by hydraulic pressure is often used in vehicles. In this power steering apparatus, typically, a hydraulic control valve is provided in a hydraulic supply path from the hydraulic pump to the hydraulic cylinder, and the operation of the hydraulic control valve is controlled based on the steering input torque or the like, thereby assisting in steering. Adjust power. As described in Patent Document 1, a check valve is provided in a flow path connecting the hydraulic pump and the hydraulic control valve. This check valve prevents a back flow from the hydraulic control valve to the hydraulic pump, and prevents the occurrence of a so-called kickback phenomenon in which the handle is removed due to the back flow.

Such check valves are roughly classified into a ball type using a ball and a poppet type using a substantially bottomed cylindrical poppet as a valve body on which a seating surface is formed. The poppet is roughly constituted by a cylindrical portion that is concentrically accommodated in the flow path of the housing, and a bottom portion that is formed at one axial end of the cylindrical portion.
Japanese Patent Laid-Open No. 11-49004

  In such a poppet type check valve, there is a possibility that so-called contamination such as metal powder is caught between the inner peripheral surface of the housing forming the flow path and the outer peripheral surface of the cylindrical portion of the poppet, and the operation cannot be performed satisfactorily. . If the gap between the inner peripheral surface of the housing and the outer peripheral surface of the cylindrical portion is simply increased so as to avoid such clogging, the poppet is likely to fall down in the longitudinal direction of the flow path, which may cause a so-called chattering phenomenon. is there.

  The present invention has been made in view of such problems, and has as its main purpose to provide a novel check valve capable of achieving both high-level prevention of poppet falling and contamination clogging. .

  A check valve according to the present invention includes a housing in which a flow path is formed, and a poppet that is accommodated and disposed so as to be movable in the longitudinal direction of the flow path and has a bottom portion at one end in the axial direction of the cylindrical portion. ing. A seating surface that can be seated on a seating surface provided in the housing is formed on the bottom. And the convex part which protrudes to radial direction outward is provided in the outer periphery of the said cylindrical part intermittently in the circumferential direction, It is characterized by the above-mentioned.

  According to the present invention, a sufficient gap can be secured between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the housing at least by the height of the convex portion. Therefore, contaminants such as foreign matter can easily flow through the gap, and contamination can be effectively avoided. Also, the convex portion protrudes radially outward, that is, toward the outer peripheral surface of the housing, and the gap between the tip of the convex portion and the outer peripheral surface of the housing can be made sufficiently small or substantially eliminated. it can. Therefore, it is possible to effectively suppress and avoid the poppet falling that causes chattering. That is, while having a simple structure in which a convex portion is provided, it is possible to achieve both high levels of suppression of contamination clogging and suppression of poppet collapse.

  The check valve manufacturing method includes a first press step for obtaining a blank material in which the poppet is developed by an outer shape punching process, and forming the convex portion on the blank material by embossing to form an intermediate molded product. And a third press step for forming the poppet from the intermediate molded product by drawing.

  Thus, after forming a convex part beforehand, since the poppet of a predetermined shape is formed by a drawing process, manufacture is easy. In other words, it is extremely difficult to form a convex portion by pressing after forming a poppet having a predetermined shape by drawing.

  Hereinafter, an embodiment in which a poppet check valve according to the present invention is applied to a hydraulic power steering apparatus for a vehicle will be described in detail with reference to the drawings.

  Referring to FIG. 1, the vehicle power steering apparatus is configured to apply a steering assisting force by a differential pressure between two hydraulic chambers formed in a power cylinder (not shown) as is well known. A hydraulic circuit including the hydraulic pump 10 and the power cylinder is provided with a hydraulic control valve 11 that controls the hydraulic pressure supplied to the two hydraulic chambers. In FIG. 1, the spool of the hydraulic control valve 11 is not shown. A check valve 12 for preventing the backflow of hydraulic oil from the hydraulic control valve 11 side to the hydraulic pump 10 side is provided in the middle of the hydraulic supply flow paths F1 to F5 from the hydraulic pump 10 to the hydraulic control valve 11. Yes.

  The check valve 12 has a cylindrical housing 13 in which a flow path F4 is formed and a substantially bottomed cylindrical shape that is accommodated in the flow path F4 and is movable along the longitudinal direction L1 of the flow path F4. An egg poppet 20 is roughly configured.

  2 and 3 are a sectional view and a bottom view showing the poppet 20 alone. The poppet 20 includes a cylindrical portion 21 disposed concentrically inside the flow path F4 and a bottom portion 22 that closes one axial end of the cylindrical portion 21, and the other axial end of the cylindrical portion 21 is open. doing. A seating surface 23 that can be seated on a seating surface 14 stepped on the housing 13 is formed on the outer surface of the bottom portion 22 that is smoothly curved and inclined. A stepped portion 24 is formed between the small-diameter cylindrical portion 21a near the bottom portion 22 and the large-diameter cylindrical portion 21b near the open end that is larger in diameter than the small-diameter cylindrical portion 21a. In addition, three windows 25 are intermittently formed in the circumferential direction in the cylindrical portion 21, and three slits 26 extending in the axial direction are intermittently formed in the circumferential direction.

  Referring again to FIG. 1, the housing 13 is formed on a fixing bolt 17 that fastens and fixes the hydraulic pipe 15 formed with the flow path F <b> 1 and the hydraulic control valve 11 together with a washer 16. The fixing bolt 17 communicates with a small-diameter channel F3 near the head 17a and a large-diameter channel F4 near the tip, and a small-diameter channel F3 and the channel F1 of the hydraulic pipe 15 that are coaxially connected in the bolt axis direction. A radial flow path F2 is formed. The large-diameter channel F4 corresponds to the channel in the housing 13 and communicates with the channel F5 of the control valve 11. The seating surface 14 is formed on the step surface between the small-diameter channel F3 and the large-diameter channel F4. The seat surface 14 is an inclined surface that expands toward the bolt tip.

  A return spring 18 as an elastic body constantly urges the poppet 20 toward the seating surface 14, and a stepped portion between the ring-shaped plug 19 and the poppet 20 fitted to the inner periphery of the front end of the fixing bolt 17 (housing 13). 24 in a compressed state. The plug 19 also functions as a stopper for the poppet 20.

  In an initial state where the differential pressure of the large-diameter channel F4 on the control valve side with respect to the small-diameter channel F3 on the hydraulic pump side is lower than the set pressure, the seating surface 23 of the poppet 20 is seated and pressed against the seat surface 14 by the return spring 18. The flow paths F3 and F4 are shut off and closed. When the pressure difference between the flow paths F3 and F4 exceeds the set pressure, the poppet 20 moves in the valve opening direction (downward in FIG. 1) against the spring force of the return spring 18 and the seating surface 23 becomes the seating surface. The valve is opened away from 14 and the flow paths F3 and F4 are communicated. As a result, the hydraulic oil pumped from the hydraulic pump 10 is formed in the cylindrical portion 21 in addition to the clearance between the seating surface 23 and the seating surface 14 and the clearance between the inner peripheral surface of the housing 13 and the outer peripheral surface of the cylindrical portion 21. It flows to the control valve 11 side through the window 25, the slit 26, and the like.

  In the present embodiment, a plurality of convex portions 27 protruding outward in the radial direction are formed on the outer peripheral surface of the cylindrical portion 21. Each convex portion 27 has a shape that protrudes into a hemisphere by embossing, which will be described later. Such convex portions 27 are provided intermittently at two locations in the axial direction and intermittently at three locations in the circumferential direction, and are provided at a total of six locations.

  As shown in FIG. 2, the projecting portion 27 protrudes toward the inner peripheral surface of the housing 13 and faces the inner peripheral surface of the housing 13 substantially without a gap. Therefore, a sufficient gap ΔD is ensured between the outer peripheral surface of the cylindrical portion 21 and the inner peripheral surface of the housing 13 by at least the height of the convex portion 27. Thereby, foreign matter and contamination are not clogged between the outer peripheral surface of the cylinder part 21 and the inner peripheral surface of the housing 13, and the malfunction of the poppet 20 by contamination etc. can be eliminated reliably. Further, since the convex portions 27 are opposed to and contacted with the outer peripheral surface of the housing 13 substantially without gaps, and a plurality of such convex portions 27 are intermittently provided in the circumferential direction and the axial direction, the chattering The fall of the poppet 20 that causes a phenomenon or the like is suppressed. That is, with a simple structure in which the convex portion 27 is provided, it is possible to achieve both high levels of suppression / prevention of clogging such as contamination and suppression / prevention of the poppet 20 falling.

  The most likely foreign object is caught at the tip of the convex portion 27 closest to the inner peripheral surface of the housing 13. In the present embodiment, since the convex portion 27 is formed in a hemispherical shape, the surface area of the tip portion of the convex portion 27 is small, and the possibility of biting in a foreign substance is extremely low. Further, the sliding resistance between the convex portion 27 and the inner peripheral surface of the housing is also suppressed to a low level. Furthermore, since the convex portion 27 is formed in a hemispherical shape as described above, the flow passage area narrowed by the convex portion 27 can be suppressed to a minimum as compared to the shape of the convex stripe 28 and the like described later, The internal pressure loss can be made sufficiently small.

  Next, with reference to FIG.4 and FIG.5, the method to manufacture the poppet 20 of the non-return valve 12 mentioned above by press work is demonstrated.

  In the first pressing step, a flat blank material 31 corresponding to the developed shape of the poppet 20 is formed from a plate-shaped material, as shown in FIG. The blank material 31 includes a substantially circular central portion 32 and three pieces 33 extending radially from the central portion 32. In the piece portion 33, a neck portion 34 having a narrow width is formed at a connection portion / root portion to the central portion 32.

  In the subsequent second pressing step, as shown in FIG. 5, the stepped portion 24 is formed in the neck portion 34 by bending, and the piece 33 is formed in a semi-cylindrical shape by bending (embossing). The convex part 27 is formed in 33, and the intermediate workpiece 31a is shape | molded from said blank material 31. FIG. Typically, the step portion 24 is bent prior to the bending of the piece portion 33 including the formation of the convex portion 27. Or you may make it perform the bending process of the level | step-difference part 24 by a 1st press process (outside shape cutting process).

  In the subsequent third pressing step, the intermediate processed product 31a is drawn at the central portion 32, and the three pieces 33 are erected in the directions close to each other to form a poppet having a final shape as shown in FIG. 20 is molded. The bottom portion 22 is formed from the central portion 32, and most of the cylindrical portion 21 is formed from the three pieces 33. The window 25 is formed between the adjacent neck portions 34, and the slit 26 is formed between the adjacent piece portions 33.

  Thus, since the convex part 27 is formed by press work before forming the final-shaped poppet 20 by drawing, processing is easy. That is, even if the convex portion 27 is formed, the intermediate processed product 31a has a substantially plate shape as a whole, and therefore does not interfere with the subsequent drawing. In other words, it is extremely difficult to form the convex portion 27 by press working after the walking poppet is formed into a final shape by drawing.

  Moreover, the convex part 27 can be easily formed by the second pressing step of forming the piece part 33 and the step part 24 by bending, that is, the convex part 27 can be formed substantially without adding a pressing process. Therefore, the pressing process can be simplified. That is, in the second pressing step, the convex portion 27 can be formed by embossing in addition to the pre-processing of the piece portion 33 and the formation of the stepped portion 22 that receives the return spring.

  As described above, the present invention has been described based on the specific embodiments. However, the present invention is not limited to the above-described embodiments, and includes various modifications and changes without departing from the spirit of the present invention. . For example, as shown in FIG. 6, it is good also considering the convex part as the protruding item | line 28 of the cross-sectional semicircular arc shape extended in an axial direction. Three ridges 28 are provided intermittently in the circumferential direction.

  Technical ideas other than the inventions described in the claims that can be understood from the above description will be listed together with their effects.

  (1) The convex portion has a hemispherical shape. In this case, the sliding area between the convex portion and the inner peripheral surface of the housing is small, and the sliding resistance is suppressed low, so that the operation of the poppet becomes smooth. In addition, the surface area of the tip of the convex portion is reduced, and the possibility of biting in foreign matter is low. Furthermore, since the convex portion is formed in a hemispherical shape as described above, the flow passage area narrowed by the convex portion can be suppressed to the minimum, and the internal pressure loss can be sufficiently reduced.

  (2) In addition to the above (1), a plurality of the convex portions are provided intermittently in the axial direction and the circumferential direction of the poppet. In this case, the fall of the poppet can be effectively suppressed, and the occurrence of chattering or the like can be effectively suppressed / avoided.

The principal part sectional view of the power steering device for vehicles to which the check valve concerning one example of the present invention is applied. Sectional drawing which shows the poppet of the non-return valve of FIG. The bottom view which shows the said poppet alone. The top view which shows the blank material which expand | deployed the said poppet. The top view which shows the intermediate molded product shape | molded from the said blank material. Sectional drawing (C) which follows the 6C-6C line | wire of the perspective view (A), bottom view (B), and (B) which show the poppet in which the protruding item | line as a modification of a convex part was formed alone.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 ... Check valve 13 ... Housing 14 ... Seat surface 20 ... Poppet 21 ... Tube part 22 ... Bottom part 23 ... Seating surface 27 ... Convex part

Claims (2)

A housing in which a flow path is formed, and a poppet that is accommodated and arranged movably in the longitudinal direction of the flow path, and has a bottom formed at one end in the axial direction of the cylindrical portion,
A seating surface that can be seated on a seating surface provided on the housing is formed on the bottom,
A check valve characterized in that a plurality of convex portions protruding radially outward are intermittently provided on the outer periphery of the cylindrical portion in the circumferential direction. A housing in which a flow path is formed and a poppet that is slidably accommodated in the longitudinal direction of the flow path and has a bottom formed at one end in the axial direction of the cylindrical portion, provided on the housing at the bottom A check valve manufacturing method in which a seating surface that can be seated on the seating surface formed is formed, and a plurality of convex portions protruding radially outward are provided on the outer periphery of the cylindrical portion in the circumferential direction. There,
A first pressing step of obtaining a blank material having a shape in which the poppet is developed by outline punching;
A second pressing step of forming the convex portion on the blank material by embossing to form an intermediate molded product;
A third pressing step of forming the poppet from the intermediate molded product by drawing;
A check valve manufacturing method comprising:

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