JP2011163423A - Ball valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball valve surely preventing the occurrence of gouging between a seat ring and an inner peripheral wall of a fluid passage at all rotation angles of a valve element with simple structure. <P>SOLUTION: The ball valve includes the valve element rotatably arranged in a housing and having an annular convex seal surface formed of a part of a spherical surface, and a seat ring elastically held (floatingly supported) in the direction orthogonal to a rotating shaft of the valve element and having an annular concave seal surface formed of a part of the spherical surface and sliding along the convex seal surface. A valve element side part of the seat ring is additionally provided with a locking member locked to the rotating shaft of the valve element. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a ball valve used for opening and closing a fluid flow path, and more particularly to a ball valve suitable for controlling a recirculation (EGR) flow rate for recirculating exhaust gas of an internal combustion engine to an intake side.

  A valve body having an annular convex seal surface formed of a part of a spherical surface, and an annular concave seal surface (valve seat) formed of a part of the same spherical surface and joined to the convex seal surface to form a seal surface A ball valve in which a cylindrical seat ring provided with the above is combined is known (Patent Document 1). The seat ring is elastically held (floating supported) in the axial direction of the fluid flow path, and is disposed orthogonal to the rotation axis of the valve body. The sliding position (contact position or thrust acting position) between the convex seal surface and the concave seal surface swings between the periphery and the center of the seal surface as the valve body opens and closes. Along with this swing, the seat ring receives thrust at a position deviated from the central axis, and frictional force due to sliding acts in the tangential direction of the spherical surface. For this reason, a twist occurs between the inner peripheral wall of the fluid flow path in which the seat ring is fitted, and this tends to cause a malfunction.

  In the invention described in Patent Document 1, a restricting member that restricts the seat ring from moving (sliding) in the axial direction to the valve body side is provided to reduce the occurrence of twisting. However, until the movement of the seat ring is restricted by the restricting member, the occurrence of the twist cannot be completely prevented. In addition, after the movement is restricted, it is difficult to appropriately adjust the rotation angle of the valve body and the valve opening, and there is a problem that the valve opening rapidly increases.

JP 2005-344803 A

  An object of the present invention is to provide a ball valve that has a simple structure and can reliably prevent the occurrence of twisting between the seat ring and the inner peripheral wall of the fluid flow path at all rotation angles of the valve body.

  According to the first aspect of the present invention, a valve body having an annular convex seal surface constituted by a part of a spherical surface is rotatably arranged in a housing, and the convex seal is constituted by a part of the same spherical surface. In a ball valve that elastically holds (floating support) a seat ring having an annular concave sealing surface that slides on the surface in a direction perpendicular to the rotation axis of the valve body, the seat ring has a valve body side portion on the valve body rotation shaft. A locking member for locking is provided.

  According to a fourth aspect of the present invention, a guide member for preventing the locking member from moving in the direction of the rotation axis is attached to the rotation axis of the valve body.

  In the first aspect of the present invention, a locking member that locks the rotary shaft of the valve body is attached to the side of the valve body such as an end of the seat ring. For this reason, it can prevent that the edge part of a seat ring shakes in the direction orthogonal to a rotating shaft. As a result, it is possible to reliably prevent the occurrence of twisting between the seat ring and the inner peripheral wall of the fluid flow path at all the rotation angles of the valve body.

  In the invention according to claim 4, since the locking member is prevented from moving in the direction of the rotation axis by the guide member, any of the direction in which the end portion of the seat ring is orthogonal to the rotation axis and the direction of the rotation axis It is possible to prevent the camera from moving in the direction. Thereby, it is also possible to prevent the occurrence of twisting between the seat ring and the inner peripheral wall of the fluid flow path due to uneven wear of the sliding surface of the seat ring, vibration applied to the seat ring, and the like.

1 is a front sectional view of a ball valve according to Example 1. FIG. 1 is a plan sectional view of a ball valve according to Example 1. FIG. It is front sectional drawing and the right view of the seat ring concerning Example 2 and Example 3. FIG. It is a mounting view of the locking member to be mounted on the valve shaft. It is a front view which shows the Example of a guide means. It is a front view which shows the other Example of a guide means.

  A mode for carrying out the invention will be described together with embodiments shown in the drawings.

  FIG. 1 is a front view of a ball valve 1 according to the present invention, and an exhaust gas recirculation for recirculating (EGR) a part of exhaust gas to an intake side by connecting an exhaust path and an intake path of an engine. It is interposed in the road 10. The ball valve 1 includes a housing 2, and a cylindrical gas flow path (fluid flow path) 21 constituting a part of the exhaust gas recirculation path 10 is provided in the housing 2. The gas flow path 21 has one end (right end in the figure) 22 on the downstream side of the exhaust gas communicating with the engine intake path, and the other end (left end in the figure) 23 on the upstream side communicating with the exhaust path of the engine. The ball valve 1 has an action of adjusting the gas flow rate to be recirculated according to the engine operating conditions.

  In the housing 2, a valve body 3 for opening and closing the gas flow path 21 and a cylindrical seat ring 4 forming a valve port (valve seat) are disposed. An actuator 11 for driving the valve body 3 is attached to the upper end of the housing 2 in the figure. The valve body 3 includes a valve shaft 31 penetrating the gas flow path 21 and pivotally supported by the housing 2 at both ends, and a disc-shaped valve plate 33 fastened to the valve shaft 31 by screws 32 as fastening means. Become. The outer periphery of the valve plate 33 is an annular convex seal surface 34 (see FIG. 2) obtained by cutting a spherical surface having a center G on the valve shaft 31 with two parallel surfaces orthogonal to the center line L. The valve plate 33 may be fixed to the valve shaft 31 by fixing means other than the screws 32.

  The valve shaft 31 is connected to the actuator 11 at the upper end shown in FIG. 1, and is rotated clockwise by the actuator 11 as shown in FIG. 2, the valve plate 33 of the valve body 3 rotates clockwise from the closed valve state (valve opening zero, rotation angle θ = 0) illustrated by a one-dot chain line ( The valve is opened) and rotated to a rotation angle θ shown in the two-dot chain line of 90 ° (fully open). The convex seal surface 34 has a central axis on the central line L of the gas flow path 21 when the rotation angle θ = 0.

  The seat ring 4 is loosely fitted on the inner circumference of the gas flow path 21 so as to be displaced or moved (slidable) in the axial direction. An inner peripheral ridge 5 is provided on the outer periphery of the seat ring 4. An urging means 6 for urging the seat ring 4 to the left in the figure is installed on the upstream side of the seat ring 4.

  As shown in FIG. 3, the seat ring 4 has a cylindrical shape, and is provided with a flange portion 41 at one end, a small outer shape portion 42 at the middle, and a large diameter portion 43 at the other end. A cylindrical portion 44 for forming a spring chamber is formed on the other end surface of the large diameter portion 43. From the collar part 41, the latching member 7 which is the summary of this invention protrudes. In this embodiment, the locking member 7 is composed of a total of four pins 71 each of which is provided on the left and right side portions of the collar portion 41 so as to project from the rotation surface of the valve shaft 31. The gap 70 between the pair of pins 71 and 71 is set to a dimension that allows the valve shaft 31 to be slidably clamped. The seat ring 4 is provided with a concave seal surface 47 as a valve seat that abuts against a convex seal surface 34 (shown in FIG. 2) on the inner periphery of one end.

  The inner peripheral ridge 5 includes a tapered widened portion 51 located on the outer periphery of the valve shaft 31 and the valve plate 33, a small inner diameter portion 52 on the upstream side, and a step portion 53. In this embodiment, the inner peripheral ridge 5 is formed as a ridge by inflating the inner periphery of the gas flow path 21, but a ring-shaped separate body is fitted into the inner periphery of the gas flow path 21. May be formed.

  The urging means 6 includes an annular support member 61 having a rectangular cross section that is fitted and fixed to the inner periphery of the other end of the gas flow path 21, and between the support member 61 and the other end surface of the large diameter portion 43. And a spring 62 as an elastic body interposed therebetween. A cylindrical lip seal 63 having a U-shaped cross section is interposed between the small inner diameter portion 52 and the small outer shape portion 42. The cylindrical lip seal 63 is an elastic body, and is arranged with the outer cylinder portion 64 abutting against the inner peripheral wall of the small inner diameter portion 52 and the inner cylinder portion 65 abutting against the small outer diameter portion 42, so The inner wall of the passage 21 is elastically supported. That is, the seat ring 4 is elastically supported or floatingly supported in the axial direction and the radial direction in the gas flow path 21 by the biasing means 6 and the cylindrical lip seal 63.

  In this embodiment, the spring 62 is an annular plate-like wave spring, and is fitted into a cylindrical portion 44 formed on the other end side of the seat ring 4. One end of the spring 62 is in contact with the other end surface of the large-diameter portion 43, the other end is in contact with the support member 61, and the seat ring 4 is urged to the right in the figure. The spring 62 as an elastic body may be a spring having another structure such as a coil spring or a disc spring, or may be an elastic body other than a spring such as an O-ring.

  The operation of the ball valve 1 will be described with reference to FIG. A dot-dash line valve plate 33 indicates a positional relationship between the valve body 3 and the seal ring 4 in a state where the rotation angle θ = 0 (fully closed). When the rotation angle θ = 0, the convex seal surface 34 and the concave seal surface 47 are in contact with each other around the entire circumference, and the contact area is maximum, and the surface pressure of the contact surface by the biasing means 6 (spring 62) is It is the lowest value.

  As the rotation angle θ increases, the convex seal surface 34 slides with the concave seal surface 47 while rotating. While the rotation angle θ is small, the contact surface (sliding surface) is on the upper and lower sides in the figure. When the width is gradually narrowed and the rotation angle θ is further increased, a gap is formed at one or both of the upper end and the lower end in the drawing, and the gas is opened (opened) and gas starts to flow.

  The contact position (sliding position) between the concave seal surface 47 of the seat ring 4 and the convex seal surface 34 of the valve body 3 is the center position (the same position as the valve shaft) when the valve is initially opened (rotation angle θ = 0). To the upper side in the figure as the rotation angle θ increases. When the rotation angle θ further increases and the valve plate 33 reaches the rotation angle θ = 90 degrees position indicated by the two-dot chain line (the position at which the valve plate 33 is parallel to the central axis L), the valve plate 33 moves to the position shown in FIG. At this position, the seat ring 4 receives thrust in the direction of the arrow K from a position eccentric to the center line L by a distance C on one end face.

  For this reason, a moment is applied to the seat ring 4 and the inner peripheral wall of the gas flow path 21 is likely to be twisted. Further, when the contact surface between the convex seal surface 34 and the concave seal surface 47 slides, a moment is applied to the seat ring 4 by receiving a frictional force in the tangential direction of the spherical surface having the center G. There will be a twist on the inner wall. When the seat ring 4 is squeezed into the inner peripheral wall of the flow path 21, it wears and the durability decreases, and the confidentiality of the contact surface between the convex seal surface 34 and the concave seal surface 47 decreases.

  In the present invention, the pair of pins 71, 71 which are the locking members 7 sandwich the valve shaft 31. For this reason, the moment applied to the seat ring 4 due to the eccentricity of the thrust acting point or the frictional force applied to the sliding surface is received by the pair of pins 71, 71. As a result, the seat ring 4 can be reliably prevented from being twisted by the inner peripheral wall of the flow path 21 in the entire range of the rotation angle θ.

  FIG. 4 shows another embodiment of the locking member 7. 4A, the locking member 7 is formed by a pair of inclined pins 73, 73 arranged in a horizontal V-shape projecting from the left and right end faces of the collar portion 41. In FIG. The valve shaft 31 is sandwiched between the pair of inclined pins 73 and 73, and the same operations and effects as in the first embodiment are achieved. 4B, the locking member 7 is constituted by a substantially C-shaped locking tool 72 fixed to the left and right end faces of the collar portion 41. In FIG. The substantially C-shaped locking tool 72 is fitted on the valve shaft 31 and has the same functions and effects as those of the first embodiment.

  FIG. 5 shows a second embodiment of the ball valve 1 of the present invention. In this embodiment, a C-ring-shaped guide means 8 that prevents the locking member 7 from moving in the axial direction of the locking member 7 in the axial direction (direction orthogonal to the central axis of the flow path 21) is fixed to the valve shaft 31. As shown in FIG. 5A, the guide means 8 supports both sides of the pins 71, 71, as shown in FIG. 5B, only supports the inside of the pins 71, 71, and further the pin. Any of those that lock only the outside of 71 and 71 may be used.

  In the second embodiment, the seat ring 4 can be held in the vertical direction and the left-right direction, and the seat ring 4 can be twisted even against an unbalanced external force due to uneven thrust left and right, friction left and right, or vibration. There is an advantage that can be surely prevented. The guide means 8 may have a ring, pincushion, or U-shaped member attached to the valve shaft 31, and the locking member 7 engages with the outer periphery of the valve shaft 31 as shown in FIG. A groove 81 or a protrusion may be provided. Further, the locking member 7 can be provided at a position other than the end face depending on the structure of the seat ring 4.

  In the ball valve 1 of the present invention, since the locking member 7 that locks the valve shaft 31 is provided on the seat ring 4, the seat ring 4 can be prevented from being twisted on the inner peripheral wall of the flow path 21, and excellent in durability. .

DESCRIPTION OF SYMBOLS 1 Ball valve 2 Housing 3 Valve body 30 Seal surface 31 Valve shaft 33 Valve plate 34 Convex seal surface 4 Seat ring 47 Concave seal surface (valve seat)
6 Biasing means 7 Locking member 8 Guide means

Claims (4)

  A valve body having an annular convex seal surface formed of a part of a spherical surface is rotatably disposed in a fluid flow path of the housing, and is configured to be a part of substantially the same spherical surface and slides on the convex seal surface. In a ball valve that elastically holds a seat ring having an annular concave sealing surface, the seat ring is provided with a locking member that is locked to the rotating shaft of the valve body and prevents the seat ring from shaking. Ball valve.   The ball valve according to claim 1, wherein the locking member is a clamping member that is provided on an end surface of the seat ring and clamps the valve shaft.   The ball valve according to claim 2, wherein the clamping member includes a pair of left and right pins.   A valve body having an annular convex seal surface formed of a part of a spherical surface is rotatably disposed in a fluid flow path of the housing, and is configured to be a part of substantially the same spherical surface and slides on the convex seal surface. In a ball valve that elastically holds a seat ring having an annular concave sealing surface, a locking member is provided on the seat ring to prevent the seat ring from being shaken by being locked to the rotating shaft of the valve body. A ball valve comprising guide means for preventing displacement of the locking member in the axial direction of the rotating shaft.

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