JP2001263498A - Annular packing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ease manufacturing tolerance on the crush allowance of an annular packing mounted to a spindle sliding in a cylinder of a valve by dissolving the impairment of watertightness and smoothness in sliding, particularly the marked impairment of smooth sliding caused by the different resiliency to a cylinder wall surface due to the change of the swinging and inclining angle of a sliding contact surface of the packing when sliding. SOLUTION: This annular packing 1 is constituted by constricting side edges 3b and 3b formed by slightly extending the semicircular edges of a sliding contact side 3a of semicircular cross section, in the width of the diameter to form the outer peripheral side of the annular packing 1 into a circular head part 2 with constricted neck parts 3c, 3c, forming a leg head part 2 of the circular head part 2 and a leg part 4 formed by extending the side edges of the constricted neck parts 3c, 3c in parallel, and integrally forming a base part 5 of a wide band shape at a base end 4a of the leg part 4 of the leg head part 2, along annular shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an annular packing for achieving watertightness between a cylinder and a valve rod which performs a stroke movement such as a spool valve in various valves such as a ball tap type valve.

[0002]

2. Description of the Related Art Conventionally, an annular packing of this type has a track-shaped cross section formed on the outer and inner peripheral sliding contact surfaces at a section R, and a peanut cross section provided with a concave portion near the center of both sides between the inner and outer circumferences. A ball-point pen-shaped cross section having a small-diameter R-shaped portion formed at the tip of the sliding contact surface formed in a shell shape or a pointed shape (see Japanese Patent Application Laid-Open No. Hei 7-269733), and an inverted T having a wide base portion. A configuration in the shape of a letter (T-shape) or the like has been proposed.

[0003] In the annular packing, it is required that the deformation (crushing) of the sliding contact surface during sliding be suppressed to 0.2 mm or less to improve both the sliding and watertight actions, and that the dimensional accuracy be strictly required. It is also known that this reduces production efficiency.

[0004]

However, with regard to these conventional annular packings, in the track-shaped packing and the peanut shell-shaped packing in cross section, the R portion has the entire width (thickness).
The largest elastic force acts in the radial direction having a height and acts obliquely in the width (thickness) direction during sliding, which inclines along the sliding direction of the outer (inner) sliding contact portion. Elastic stress is applied, causing a phenomenon that the sliding resistance increases at the time of starting, especially when the sliding direction is switched, and the sliding does not occur smoothly.

[0005] Next, in the ball-point pen-shaped packing having a cross-section, the tip R-shaped part forms a part of a pointed part that spreads out in an octagonal shape. However, since uniform elastic force is difficult to work, water tightness is poor, and smoothness at the time of starting is also lacking.

Further, since the annular packing having the inverted T-shaped cross section has the same thickness due to its configuration, the elastic stress on the cylinder wall at the outer peripheral or inner peripheral end works the largest in the diametric direction like other packings. The elastic stress differs depending on the inclination angle of the outer and inner peripheral edges against the cylinder wall during sliding, which hinders watertightness and smooth sliding at the time of starting.

As described above, all of the conventional annular packings have different elastic stresses due to a change in the pressure contact angle of the outer and inner peripheral edges to the cylinder wall during sliding, and smooth sliding and reliable watertightness are expected. Can not. In particular, when starting to switch the sliding direction, the sliding resistance is maximized and smooth sliding cannot be started, so that the valve cannot be opened and closed accurately, and the deformation (crushing) allowance on the sliding surface of the packing is allowed. There are problems such as demanding strict precision in manufacturing that must clear the range.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has an outer periphery or an inner periphery of an annular packing made of an elastic material such as rubber, and has a semicircular cross-section. The side which slightly extended the end by the width of the diameter is constricted to form a circular head having a constricted small neck,
An annular packing is proposed in which both sides of the constricted small neck portion of the circular head are extended in parallel to form legs having cavities on both sides to form heads and legs.

A circular head having a semicircular cross section of the annular packing mounted on the sliding shaft or cylinder wall of the valve is pressed against the annular radial cylinder wall surface or sliding shaft surface in a water-tight manner by elastic force to slide. When the circular head tilts slightly along the sliding direction during movement, the elastic stress due to the tilting is absorbed by the legs having the cavity, and the circular head has a circular cross section by the narrow neck. Has a cross section of the same diameter in any direction, and this becomes an elastic force acting equally in each direction of the oscillating inclination, so that reliable watertightness and smooth sliding can be obtained. Smooth starting at switching.

[0010] A circular head diagonally opposing the constricted small neck,
Packing formed in a concave radius in the same direction as the arc side,
By controlling the oscillating inclination stress of the circular head during sliding, the sliding resistance is applied uniformly in any direction to ensure watertightness, and to assist the inclination restoring force at the time of switching the sliding direction. Makes movement and starting smoother.

A base provided at the base end of the leg stably supports the circular head and forms a concave corner at the corner with the leg, thereby ensuring watertightness and sliding. And make the startup even smoother.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an annular packing according to the present invention will be described. The annular packing is a receiving groove provided on an outer peripheral surface of a valve stem or a cylinder inner peripheral surface which moves in stroke in various valves such as a ball tap type valve. It is made of elastic material such as rubber, urethane rubber, etc., and the entire cross section integrally provided with the base and the head and legs is formed in a convex or inverted convex annular shape, The sliding edge of the outer or inner circumference of the head leg is formed in a semicircular cross-section, and the arc-shaped end of this semicircular cross-section is slightly narrowed on both sides which are slightly extended by the width of the diameter to form a narrow neck. A circular head having a circular head, and a constricted small neck of the circular head is extended in parallel to form a leg having a cavity on both sides at both sides to form a head and a leg having a whole cross section of a tree. A wide band-shaped base portion at the base end of the leg portion in the centripetal direction of the head leg portion. Constituting the annular packing connected integrally molded along Jo.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the annular packing will be described with reference to FIGS. 1 to 5. FIG. 1 is a front view showing a partially cutaway embodiment of the annular packing according to the present invention, and FIG. , FIG. 3 is a cross-sectional view of a ball tap valve provided with an annular packing, FIG. 4 is a cross-sectional view of a main part of the annular packing when sliding, and FIG. 5 is a deformed state of the annular packing when sliding. FIG. 2 is a cross-sectional view of a main part showing
Is formed integrally with a convex section in cross section with a head part 2 provided on the outer peripheral side and a base part 5 provided on the inner peripheral side, and the outer peripheral sliding contact side 3a is formed in a semicircular cross section. A circular head 3 formed by narrowing both sides 3b, 3b, each of which has a semicircular cross-sectional end slightly extended by the width of its diameter (R), and a constriction extending in parallel from its constricted small neck 3c. And a leg 4 having a cavity 6 formed on both sides on both small sides, and the base end 4a of the leg 4 of the head leg 2 is integrated with the center of the wide band base 5 in the width direction along the ring. To form an annular packing 1.

A radius (R) of the sliding contact side 3a is provided at a corner of the constricted small neck 3c which is diagonally opposed to the cross-sectional arc of the sliding contact side 3a of the circular head 3.
And a corner portion between the base 5 and the base end 4a of the leg 4 is similarly provided with an arc (arc), and the annular packing 1 As shown in FIGS. 3 and 4 in the embodiment, a ball-tap valve 8 is used in a ball-tap valve 8 and a receiving groove 9b provided on a spool 9a of a spindle 9 in a ball-tap valve 8 is made of a hard material such as a synthetic resin. An endless or endless annular support frame 7,
7 is attached from above and below.

The spindle 9 on which the packing 1 is mounted is slid up and down in the cylinder 8a by a lever 11 connected to a lever rod 10 which swings up and down by the buoyancy of the tip float, and the valve 9c on the spindle 9 is used as a valve. The fluid is supplied or stopped by opening and closing the valve seat portion 8b of FIG.

As shown in FIGS. 4 and 5, the radius (arc) provided on the constricted small neck 3c of the circular head 3 functions as a smooth resistance to the oscillating tilt stress during sliding. When the sliding direction is switched, the stress caused by the swing inclination of the sliding contact side 3a of the circular head 3 is controlled by a broken line, and the restoring force at the time of changing the swing direction is assisted to make the sliding and starting smoother.
In addition, a reliable watertightness can be obtained.
By setting the value to 2 to 36%, the above-mentioned balanced action can be easily obtained.

Further, by providing a round (arc) portion similar to the constricted small neck portion 3c at a corner between the base end 4a of the leg portion 4 and the base portion 5, smoother starting and sliding can be obtained. It is something that can be done.

[0018]

FIG. 6 shows another embodiment of the annular packing shown in FIG. 6, in which a circular head 3 and a leg 4 formed with the width of a constricted small neck 3c having no radius are formed. In the packing 1 formed and integrally formed by connecting the base end 4a of the leg portion 4 to the base portion 5 so that the center portion of the leg portion 4 hits the extended circumference of the circular head portion 3 having a semicircular cross section. Stenosis, small neck 3c to proximal end 4
By setting the length (height) of the leg 4 up to a
The circular head 3 has a circular cross section and a diameter equal in any direction, and an equal elastic force acts in any direction orthogonal to the annular radial direction. In addition to this, the rocking inclination stress during sliding is absorbed by the constricted small neck 3c and the cavity 6 of the leg 4, so that the elastic force works evenly on any rocking inclination to ensure watertightness. And smooth sliding can be obtained.

The annular packing 1 in these embodiments is
The length (height) of each part in the radial direction of the ring is set to 45-49 with respect to the sectional radius (R) of the sliding contact side 3a of the circular head 3 and the side 3b following the arc side end of the sliding contact side 3a. %, Legs 88-92
%, The base portion 5 is 154 to 158%, and the width (thickness) of the base portion 5 is 497 to 503%, and the narrowing rate on both sides of the leg portion 4 forming the hollow portion 6 is slid. By setting the width (thickness) of the leg 4 to 36 to 38% with respect to the sectional radius (R) of the contact side 3a, the balance between watertightness and smooth sliding is best maintained. It has been confirmed by experiments that the sliding head 3
The circular head 3 having a circular cross section is formed by the fact that the circumference of the cross section radius of a extends to the center in the length (height) direction of the leg 4.
Can exert an effect that elasticity works uniformly in any direction perpendicular to the annular radial direction.

[0020]

(Equation 1)

Here, the dimensional values of these ratios will be described by the above equation (1). The squeezing rate of the leg 4 is determined by the amount by which the sliding contact side 3a of the circular head 3 is deformed in the sliding direction during sliding. In order to minimize the bending stress generated at the base end 4a corresponding to y,
A relatively small value of 36 to 38% of the sectional radius (R) of the sliding contact side 3a. At this time, the amount x by which the sliding contact side 3a of the circular head 3 is deformed in the radial direction is approximated from the result of the numerical analysis, assuming that the distance from the base end 4a to the sliding contact side 3a of the circular head 3 is L. Equation (1) above was expressed. The range of this dimension value is such that the appropriate value x necessary for obtaining smooth sliding while maintaining reliable watertightness does not unnecessarily increase the value y and minimizes the bending stress at the base end 4a. It is obtained by using the relational expression of the equation (1) so that the control can be performed, and this is confirmed by an experiment.

As in the case of the annular packing shown in FIG. 7, the packing 1 is composed of only the head and legs 2 composed of the circular head 3 and the legs 4, and the sliding at the time of sliding is performed by the narrow neck 3c and the cavity 6. Edge 3
a) The water tightness and the smoothness of sliding can be obtained because the stress caused by the crushing and the oscillating inclination of a can be absorbed, and the allowable range of the crushing allowance in manufacturing is further increased, thereby increasing the production efficiency. And the like.

In each of the above embodiments, the annular packing 1 in which the circular head 3 of the head and legs 2 is provided on the outer peripheral side and the legs 4 are provided on the inner peripheral side is described. It is also possible to configure the annular packing 1 (not shown) by replacing the inner and outer peripheral sides and providing them in reverse.

[0024]

The annular packing according to the present invention has the above-described structure. The circular head of the packing having a circular cross section is formed by the leg having the constricted small neck and the cavity, which is caused by crushing and sliding inclination during sliding. By utilizing the action of absorbing the stress and uniformly applying elastic force in any direction of the circular head,
As a result, the pressure of the circular head against the cylinder wall during sliding can be maintained uniformly.

Therefore, the elastic force applied to the cylinder wall does not change regardless of the direction of the tilting of the sliding side of the circular head of the packing when sliding in the valve, so that smooth sliding can be obtained. In addition to the remarkable start-up at the time of the change of the sliding direction, a reliable watertightness is similarly obtained, and the allowable amount of the crushing allowance is increased in manufacturing, thereby improving the production efficiency.

[Brief description of the drawings]

FIG. 1 is a front view of an annular packing embodying the present invention, showing a part of the packing;

FIG. 2 is an enlarged sectional view showing a main part of an annular packing in FIG. 1;

FIG. 3 is a front view showing a main portion of a ball tap type valve equipped with an annular packing according to the present invention in a longitudinal section.

FIG. 4 is an enlarged sectional view showing a main part of the valve of FIG. 3;

FIG. 5 is a sectional view showing a deformed state of the annular packing in FIG. 4 in a sliding process.

FIG. 6 is a partially cutaway front view showing an annular packing according to another embodiment of the present invention.

FIG. 7 is a partially cutaway front view of an annular packing according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Packing 2 Head and leg part 3 Circular head part 3a Sliding contact side 3b Side 3c Constricted small neck part 4 Leg part 4a Base end 5 Base part 6 Cavity part

Claims (4)

[Claims] An outer periphery or an inner periphery of an annular packing is formed to have a semi-circular cross-section, and a side edge formed by slightly extending an arc side end of a sliding contact side by a width of the diameter is reduced to reduce the width. An annular packing comprising a circular head having a neck, and a head formed by the circular head and legs formed by extending the constricted small neck in parallel. 2. The annular packing according to claim 1, wherein the head and leg portion is formed by forming a constricted small neck portion in a concave round shape in the same direction as a cross-sectional arc side of a circular head portion facing diagonally. 3. The annular packing according to claim 1, wherein the head leg is formed by integrally forming a wide base at a base end of the leg along a ring. 4. The annular packing according to claim 3, wherein the base portion has a corner formed with a leg portion in a concave round shape.