JP2011112135A - Ball valve - Google Patents

Abstract

When a wave washer is provided to bring a fixed sheet into close contact with a valve body, a large deflection is generated in the wave washer so that a sliding resistance when the valve body is rotated is not increased. .
A ball valve including a valve body 2 that rotates around a shaft 3, a fixed seat 4 on which the valve body is seated, and a wave washer 5 that biases the valve body in a direction in close contact with the fixed seat. , The wave washer is formed so as to have only two portions curved in a substantially S shape at the peak portion 21 and the valley portion 22, and the diameter connecting the apex portions of the two peak portions protruding to the valve body side In order to hold the wave washer at an angular position whose direction is substantially parallel to the axial direction of the shaft, a positioning pin 24 is attached to the fixing member 7 and a notch 25 fitted to the positioning pin 24 is provided in the wave washer 5.
[Selection] Figure 3

Description

  The present invention relates to a ball valve in which a valve body and a fixed seat are brought into close contact with a spring urging force of a wave washer.

  The ball valve employs a seal structure in which the valve body and the fixed seat are brought into close contact with each other with a spring urging force, and a structure using a wave washer (wave washer) as a spring for obtaining the spring urging force (see Patent Document 1) A configuration using a spring washer is known (see Patent Document 2).

JP 2005-521006 A JP 2005-061506 A

  However, in the configuration using the spring washer, the movable seat that contacts the valve body is urged at one point on one end of the spring washer on the valve body side, so that the surface pressure of the movable seat against the valve body is increased. There is a problem that the direction becomes non-uniform and causes a defect such as a seal failure due to one piece.

  On the other hand, in the configuration using the wave washer, the apex portions of the plurality of crests that are convex on the valve body side abut on the movable sheet, and the crests are arranged at equal intervals in the circumferential direction. The surface pressure of the movable sheet with respect to the valve body is uniform in the circumferential direction, and there is an advantage that it is possible to prevent one-side contact.

  However, if the wave washer is provided with a number of portions (four in the conventional example) that are curved in an S shape at the crest and trough, as in the conventional configuration, the rotation of the valve body is used. With the movement, there is a high possibility that a peak that protrudes toward the valve body is pushed and a large deflection occurs in the peak. The large deflection generated in such a wave washer excessively increases the surface pressure of the seat and increases the sliding resistance when the valve body is rotated. Therefore, a large torque is required for the actuator that drives the valve body. In addition, there is a problem that the apparatus is increased in size and the manufacturing cost is increased.

  The present invention has been devised to solve such problems of the prior art, and the main object of the present invention is to provide a wave washer when a wave washer is provided to bring the valve body and the fixed seat into close contact with each other. It is an object of the present invention to provide a ball valve that is configured so that the sliding resistance does not increase when the valve element is rotated due to the occurrence of large deflection.

  A first invention made to solve the above-mentioned problems is that a valve body (2) that rotates around a shaft (3), a fixed seat (4) on which the valve body is seated, and the valve on the fixed seat A ball valve (1) provided with a wave washer (5) for urging the body in a close-contact direction, wherein the wave washer is substantially S-shaped with a peak (21) and a valley (22). The wave washer is formed so as to have only two curved parts, and the wave washer is positioned at an angular position where the diameter direction connecting the apex parts of the two peak portions projecting toward the valve body is substantially parallel to the axial direction of the shaft. It is set as the structure provided with the washer angle holding means which hold | maintains.

  According to this, in the wave washer, each apex portion of the two peaks protruding toward the valve body is located in a direction substantially parallel to the axis of the shaft, that is, the rotation center line of the valve body. Since the wave washer is not greatly displaced as the body rotates, that is, the wave washer is not greatly bent, it is possible to avoid an increase in sliding resistance when the valve body is rotated.

  A second invention made to solve the above-mentioned problems is that, in the first invention, the movable sheet (6) having a circular seating surface (12) contacting the valve body, and the movable sheet A fixing member (7) supported via a wave washer, and the wave washer is sandwiched between a receiving surface (8) of the fixing member and a receiving surface (9) of the movable sheet.

  According to this, since the valve body comes into contact with the circular seat surface of the movable seat, the valve body can be stabilized. In this case, the wave washer abuts against the movable sheet at the apex portions of the two peak portions, and abuts against the fixed member at the bottom point portions of the two valley portions. The movable sheet is provided on the side opposite to the fixed sheet with the valve body interposed therebetween.

  According to a third aspect of the present invention for solving the above-mentioned problems, in the second aspect of the present invention, the washer angle holding means is a washer positioning means for positioning the wave washer on the fixing member.

  According to this, since the wave washer is positioned at a required angular position by the washer positioning means, the wave washer can be easily assembled.

  According to a fourth aspect of the present invention for solving the above-mentioned problems, in the third aspect of the present invention, the washer positioning means includes a convex portion (positioning pin 24) and a concave portion (notch 25) that can be engaged with each other. In the vicinity of the bottom point of the trough of the wave washer, one of the wave washer and the fixing member is provided with a convex portion and the other is provided with a concave portion.

  According to this, since the wave washer and the fixing member are closest to each other in the vicinity of the bottom part of the valley portion of the wave washer, by providing the convex portion and the concave portion as the washer positioning means, the wave washer becomes the fixing member. Positioning can be ensured. In addition, since the wave washer and the movable sheet are most separated from each other in the vicinity of the bottom portion of the valley portion of the wave washer, it is possible to avoid the washer positioning means, in particular, the convex portion from contacting the movable sheet. In addition, each bottom point part of two trough parts of a wave washer is located in the diameter direction orthogonal to the axial direction of a shaft.

  According to a fifth aspect of the present invention for solving the above-described problems, in the fourth aspect, the washer positioning means (the positioning pin 24 and the notch 25) is provided at a position corresponding to the inner peripheral portion of the wave washer. The configuration is as follows.

  According to this, the washer positioning means is disposed at a position near the center of the wave washer, and since the displacement of the movable sheet is small at this position, it is ensured that the washer positioning means, in particular, the convex portion contacts the movable sheet. Can do.

  Thus, according to the present invention, each apex portion of the two crests that protrude toward the valve body in the wave washer is positioned in a direction substantially parallel to the axis of the shaft, that is, the rotation center line of the valve body, In this position, the wave washer is not greatly displaced with the rotation of the valve body, i.e., the wave washer is not greatly deflected, so that an increase in sliding resistance when the valve body is rotated is avoided. be able to. For this reason, a large torque is not required for the actuator for opening and closing the valve body, and the size and cost can be reduced.

It is sectional drawing which shows the ball valve by this invention. It is a perspective view which shows the wave washer etc. which were shown in FIG. It is sectional drawing which shows the deformation | transformation condition of the wave washer in the ball valve shown in FIG. It is sectional drawing which shows the deformation | transformation condition of the wave washer in the comparative example of a ball valve. It is a graph which shows the characteristic of a wave washer.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a ball valve 1 according to the present invention includes a spherical valve body 2, a shaft (valve shaft) 3 that causes the valve body 2 to open and close, and a fixed seat 4 on which the valve body 2 is seated. And a wave washer 5 for urging the fixed body 4 in a direction in which the valve body 2 is brought into close contact therewith. The ball valve 1 is an EGR valve that is provided in the middle of a recirculation path for returning a part of the exhaust gas discharged from the internal combustion engine to the intake side, and controls the flow rate of the EGR gas. Is controlled. An actuator (not shown) is connected to the shaft 3 and the valve body 2 is driven to open and close by the torque of the actuator.

  The ball valve 1 further includes a movable seat 6 provided on the side opposite to the stationary seat 4 with the valve body 2 interposed therebetween, and a stationary member 7 that supports the movable seat 6 via a wave washer 5. The wave washer 5 is sandwiched between the receiving surface 8 of the fixed member 7 and the receiving surface 9 of the movable sheet 6, and the wave washer 5 is compressed and deformed. The fixed member 7 and the fixed sheet 4 are integrally held in a casing (not shown), the valve body 2 can be rotated within a required angle range, and the movable sheet 6 can be tilted within a required angle range. It has become.

  Each of the fixed sheet 4 and the movable sheet 6 has a circular shape that contacts the valve body 2, more specifically, a spherical or frustoconical seat surface 11, 12. The fixed sheet 4 is located on the downstream side of the valve body 2, the movable sheet 6 is located on the upstream side of the valve body 2, and the urging force obtained by compressing and deforming the wave washer 5 is transmitted via the movable sheet 6. By acting on the valve body 2, the valve body 2 is pressed against the fixed sheet 4, and a surface pressure is obtained to obtain a required sealing property that prevents leakage of fluid (EGR gas) from the fixed sheet 4. . Further, the wave washer 5 ensures a required urging force that prevents the valve body 2 from being separated from the fixed seat 4 due to vibrations from the outside.

  In the EGR valve, if the upstream pressure (exhaust pressure) is higher than the downstream pressure (intake pressure), and the fixed seat 4 is arranged on the upstream side of the valve body 2, the wave washer 5 has a pressure difference between the intake and exhaust. Although the urging | biasing force to resist is required, since the fixed seat | sheet 4 is arrange | positioned downstream of the valve body 2 here, the big urging | biasing force is not required for the wave washer 5. FIG.

  The shaft 3 is connected to the valve body 2 by fitting the connecting portion 13 formed at the tip of the connecting portion 13 into the connecting hole 14 formed in the valve body 2, and the connecting hole 14 extends in one direction from the connecting portion 13. It is formed long and the valve body 2 is movable in one direction with respect to the connecting portion 13. The moving direction of the valve body 2 coincides with the center line direction of the fixed seat 4 in the fully closed state shown in FIG. 1A, and the valve body 2 can be brought into and out of contact with the fixed seat 4 in the fully closed state. Thus, automatic alignment of the valve body 2 with respect to the fixed seat 4 is performed, and high sealing performance can be obtained.

  In the fully open state shown in FIG. 1 (B), the valve hole 15 opened in the center of the valve body 2 is communicated with the center hole 16 of the fixed seat 4 and the center hole 17 of the movable seat 6, and fluid (EGR gas) Sequentially flows through the center hole 19 of the upstream fixing member 7, the inside of the wave washer 5, and the center hole 17 of the movable seat 6 into the valve hole 15, and then flows downstream through the center hole 16 of the fixed seat 4. Flowing.

  As shown in FIG. 2, the wave washer 5 is alternately formed with peak portions 21 that protrude toward the valve body 2 and valley portions 22 that protrude toward the opposite side of the valve body 2. The number of portions (hereinafter referred to as wave numbers) that are curved in an approximately S shape between 21 and the valley portion 22 is set to 2. The wave washer 5 is disposed at an angular position where the diameter direction connecting the apex portions of the two peak portions 21 is substantially parallel to the axial direction of the shaft 3, and the bottom portions of the two valley portions 22 are arranged. The connecting diameter direction is a direction substantially orthogonal to the axial direction of the shaft 3.

  As shown in FIG. 3A, the wave washer 5 is in contact with the receiving surface 9 of the movable sheet 6 at the apex portion of the two peak portions 21, and is received by the fixing member 7 at the bottom portion of the two valley portions 22. Abuts against the surface 8.

  Here, when the valve body 2 is rotated in the opening direction from the fully closed position, as shown in FIG. 3B, the valve body is caused by the frictional force between the valve body 2 and the seating surface 12 of the movable seat 6. The movable sheet 6 tilts with the rotation of 2. At this time, each apex portion of the two peak portions 21 in contact with the receiving surface 9 of the movable sheet 6 in the wave washer 5 is substantially parallel to the axis of the shaft 3, that is, the rotation center line of the valve body 2. Since the movable sheet 6 is not greatly displaced at this position, the peak portion 21 is not greatly bent.

  Further, a trough 22 of the wave washer 5 is located on the side where the distance between the movable sheet 6 and the fixed member becomes narrower as the movable sheet 6 tilts. The trough 22 is a receiving surface 9 of the movable sheet 6. Therefore, it is not pushed by the movable sheet 6 and the valley portion 22 is not greatly bent.

  By the way, as shown in FIG. 2, the receiving surface 8 of the fixing member 7 is formed one step lower than the peripheral portion thereof, and the wave washer 5 is formed on the receiving surface 8 by the step surface 23 around the receiving surface 8. Deviation in the direction along is regulated. On the other hand, also on the movable sheet 6 side, the shift of the wave washer 5 is regulated by the step surface around the receiving surface 9 (see FIG. 1).

  Further, the wave washer 5 may rotate around the center line of the wave washer 5 as the valve body 2 rotates, and the angular position may change. Therefore, in order to hold the wave washer 5 at a predetermined angular position, a positioning pin (convex portion) 24 is attached to the fixing member 7, and a notch (concave portion) 25 fitted to the positioning pin 24 is provided in the wave washer 5. Is provided.

  The positioning pin 24 is provided on the receiving surface 8 of the fixing member 7 at a radial position substantially orthogonal to the axial direction of the shaft 3 so as to protrude in the center line direction of the fixing member 7. On the other hand, the notch 25 is provided in the vicinity of the bottom portion of the valley portion 22 of the wave washer 5. Therefore, by attaching the wave washer 5 so that the notch 25 is fitted to the positioning pin 24, the diameter direction of the wave washer 5 connecting the apex portions of the two peak portions 21 is substantially parallel to the axial direction of the shaft 3. Is positioned at the angular position.

  In the vicinity of the bottom portion of the valley portion 22 of the wave washer 5, the wave washer 5 and the fixing member 7 are closest to each other, and the wave washer 5 is reliably positioned on the fixing member 7 by arranging the positioning pin 24 here. can do. Further, in the vicinity of the bottom portion of the valley portion 22 of the wave washer 5, the wave washer 5 and the movable sheet 6 are most separated from each other, so that the positioning pin 24 can be prevented from contacting the movable sheet 6.

  In particular, here, the notch 25 is provided in the inner peripheral portion of the wave washer 5, and the positioning pin 24 is disposed at a position near the center of the receiving surface 8 of the fixed member 7, and at this position, the movable sheet 6 Since the displacement is small, when the movable sheet 6 tilts in the direction opposite to that shown in FIG. 3B, or on the opposite side to the position shown in FIG. 3B across the center line of the receiving surface 8 When the positioning pin 24 is disposed, it can be reliably avoided that the positioning pin 24 contacts the movable sheet 6.

  Here, for comparison, an example of a wave washer with many wave numbers set will be described. In the ball valve 41 shown in FIG. 4, a wave washer 42 having a wave number set to 3 is used. In this case, as shown in FIG. 4A, the apex portions of the three peak portions 43 abut on the receiving surface 9 of the movable sheet 6, and the bottom points of the three valley portions 44 are the receiving surfaces 8 of the fixing member 7. Abut.

  Then, as shown in FIG. 4B, when the movable sheet 6 is tilted with the rotation of the valve body 2, one peak portion 43 located on the side where the distance between the movable sheet 6 and the fixed member 7 becomes narrower. Then, it is pushed by the movable sheet 6 to cause a large deflection. For this reason, an excessive stress is generated in the wave washer 42 and the wave washer 42 is damaged. Further, since the wave washer 42 is greatly bent, the surface pressure of the fixed sheet 4 and the movable sheet 6 and the valve body 2 is increased, and accordingly, the sliding resistance when the valve body 2 is rotated is increased. Therefore, a large torque is required for the actuator, resulting in an increase in the size of the device and an increase in manufacturing cost.

By the way, if the wave number is set to a large value in the wave washer to disperse the displacement, it is possible to suppress the occurrence of excessive stress. However, the spring constant k of the wave washer is 4 of the wave number N as shown in Equation 1. Since it is proportional to the power, as shown in FIG. 5A, when the wave number N is increased, the spring constant k rapidly increases.
P = Ebh ³ N ⁴ δ / (1.94 Dm ³ ) (Formula 1)
Here, P is the pressing load, E is the Young's modulus, b is the width, h is the thickness, N is the wave number, δ is the displacement, and Dm is the average diameter.

Here, the spring constant can be lowered by increasing the average diameter Dm of the wave washer, but it is not practical because the dimension of the wave washer becomes extremely large. Although a method for reducing the thickness h of the wave washer is also conceivable, as shown in Equation 2, since the contribution to the stress σ is in a proportional relationship, the stress σ cannot be sufficiently reduced.
σ = 12EhN ² δ / (π ² Dm ² ) (Formula 2)

  Further, when the spring constant is increased by increasing the wave number N, as shown in FIG. 5B, the set length of the wave washer, that is, the distance between the receiving surfaces 8 and 9 of the fixed member 7 and the movable sheet 6 is increased. The variation in holding load is larger than the variation in. Since the sliding resistance when the valve body 2 is rotated increases as the pressing load increases, if the variation in the pressing load is large, it is necessary to set the torque of the actuator with the upper limit value of the sliding resistance. The actuator becomes larger than necessary.

  As described above, by setting the wave number of the wave washer 5 to be small, specifically, by setting the wave number to 2, the spring constant can be lowered without increasing the size of the wave washer 5. The variation in the pressing load due to the variation in the pressure can be reduced, and as a result, the sliding resistance when the valve body 2 is rotated can be reduced.

  Further, by arranging the wave washer 5 so that the diameter direction connecting the apexes of the two peak portions 21 protruding toward the valve body 2 in the wave washer 5 is substantially parallel to the axis of the shaft 3, the wave washer 5 is arranged. Therefore, it is possible to prevent the wave washer 5 from being damaged due to excessive stress, and further to prevent the wave washer 5 from being damaged. An increase in sliding resistance can be avoided. For this reason, a large torque is not required for the actuator, and the size and cost can be reduced.

  In the above example, as the washer positioning means for positioning the wave washer to the fixed member, the fixed member is provided with a convex portion (positioning pin) and the wave washer is provided with a concave portion (notch). In addition, a configuration in which a convex portion is provided on the wave washer and a concave portion is provided on the fixing member is possible.

  Furthermore, the washer positioning means for positioning the wave washer on the fixed member is not limited to the configuration of the convex portion and the concave portion as described above. For example, the wave washer is formed in an elliptical shape, and the recess of the fixing member in which the wave washer is disposed is formed in an elliptical inner shape corresponding to the outer shape of the wave washer so that the wave washer is positioned. May be.

  Further, as in the above-described example, if a washer positioning means for positioning the wave washer to the fixed member is provided as the washer angle holding means for holding the wave washer at a predetermined angular position, there is an advantage that the wave washer can be easily assembled. However, the present invention is not limited to this. For example, an adhesive may be used as the washer angle holding means, and the wave washer may be bonded and fixed to the fixing member.

  In the above example, the urging force of the wave washer is applied to the valve body via the movable sheet. However, a configuration in which the movable sheet is omitted and the wave washer is directly brought into contact with the valve element is also possible. In this case, since the valve body is supported by point contact, from the viewpoint of stabilizing the valve body, the valve body is supported by line contact or surface contact by the circular seating surface of the movable seat as in the above example. And good.

DESCRIPTION OF SYMBOLS 1 Ball valve 2 Valve body 3 Shaft 4 Fixed sheet | seat 5 Wave washer 6 Movable sheet | seat 7 Fixed member 8 Receiving surface 9 Receiving surface 11 Seating surface 12 Seating surface 13 Connection part 14 Connection hole 21 Mountain part 22 Valley part 24 Positioning pin (convex part) )
25 Notch (recess)

Claims (5)

A ball valve comprising: a valve body that rotates about a shaft; a fixed seat on which the valve body is seated; and a wave washer that biases the valve body in a direction in close contact with the fixed sheet;
The wave washer is formed so as to have only two portions that are curved in a substantially S shape at a peak portion and a valley portion, and a diametrical direction that connects the apex portions of the two peak portions that protrude toward the valve body side. A ball valve comprising: a washer angle holding means for holding the wave washer at an angular position substantially parallel to the axial direction of the shaft.   A movable sheet having a circular seating surface in contact with the valve body; and a fixed member that supports the movable sheet via the wave washer, and a receiving surface of the fixed member and a receiving surface of the movable sheet The ball valve according to claim 1, wherein the wave washer is sandwiched therebetween.   The ball valve according to claim 2, wherein the washer angle holding unit is a washer positioning unit that positions the wave washer on the fixing member.   The washer positioning means includes a convex portion and a concave portion that can be engaged with each other, and a convex portion is provided on one of the wave washer and the fixing member in the vicinity of the bottom portion of the valley portion of the wave washer. The ball valve according to claim 3, wherein a recess is provided on the other side.   The ball valve according to claim 4, wherein the washer positioning means is provided at a position corresponding to an inner peripheral portion of the wave washer.

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