JPH065111B2 - Ball valve - Google Patents

Description

The present invention relates to an improvement of a mechanism for rotating a spherical valve body of a ball valve.

[Prior Art] A ball valve is provided with a valve body having an inlet and an outlet, and a spherical valve body having a passage penetrating the center thereof. When the spherical valve body is rotated to connect the passage to the inlet and the outlet. The valve opens and closes when communication is cut off. The spherical valve element is driven by the rotation of a stem attached to the valve body, and the stem is rotated manually or automatically. As for the stem and the spherical body, the engaging piece provided on the lower end of the stem is inserted into the engaging groove provided on the upper spherical surface of the spherical valve body to connect with each other, but as shown in Japanese Utility Model Laid-Open No. 62-114277, The conventional engagement piece is a fan-shaped plate body having two parallel surfaces,
The engaging groove is a fan-shaped groove having two parallel surfaces having the same width as the two parallel surfaces of the engaging piece, and they are in planar contact with each other.

[Problems to be Solved by the Invention] As shown by the solid line in FIG. 4, there is no problem if the stem 30 of the ball valve and the spherical valve body 20 are always coaxial. Stem axis A due to time error
If the shaft center A2 of 1 and the spherical valve disc shifts, the stem is twisted in the lateral direction and the rotational friction accumulates and becomes large, and the spherical valve disc 20 swings, which makes it impossible for the seat that receives the spherical valve disc. The force is applied and the durability of the seat decreases. Also, the fifth
Even if the stem 30 and the spherical valve body 20 are coaxial with each other during manufacturing and assembly as shown by the solid line in the figure, as shown by the chain line, the spherical valve body 20 flows in the flow direction due to the fluid pressure p when the valve is closed. When pushed to, the stems 30 and the rotational axes A1 and A2 of the spherical valve body 20 are displaced. When the stem 30 is rotated to open the valve in this state, the state shown by the chain line in FIG. 4 is obtained, the stem twists laterally, and the required torque for opening and closing the valve greatly increases.

As described above, the conventional ball valve has a problem that extra torque is required for opening and closing the valve because the stem 30 is twisted. In particular, in the case of an automatic valve, when the required torque becomes large, there is a problem that the drive unit becomes large and the cost becomes significant.

The present invention has been made to solve the above problems, and an object of the present invention is to significantly increase the torque for opening and closing the valve even if the stem and the rotational axis of the spherical valve element are deviated, and to improve the durability of the seat. The purpose of the present invention is to provide a ball valve that does not deteriorate in performance.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the means adopted by the present invention is that the engaging piece at the lower end of the stem is attached to the engaging groove on the upper spherical surface of the spherical valve body in the engaging groove. In the ball valve of the method of coupling, the two contact surfaces that extend in the longitudinal direction of the engaging pieces that contact each other are formed in an arc shape that bulges outward in cross section, and the two contact surfaces that extend in the longitudinal direction of the engaging groove are It was formed on parallel planes.

[Operation] When the ball valve is assembled, even if the axis of the stem deviates from the axis of the spherical valve due to an error, or the axis of the spherical valve coincides with the axis of the stem when the valve is opened. Even if is displaced by fluid pressure when the valve is closed, the engaging piece and the engaging groove are in line contact with each other on the flat surface and the arcuate surface, so that they can easily slide against each other. Therefore, neither the stem is laterally twisted by the spherical valve body nor the spherical valve body is swung by the stem. Also, the torque required to open and close the valve is almost the same as when the stem and the spherical valve element are aligned with each other.

[Embodiment] A ball valve of the present invention will be described based on an embodiment shown in the drawings. As shown in FIGS. 1 and 2, the valve body of the ball valve
Reference numeral 10 is a body portion 11 and a flange portion 12 connected by a bottle 13 and a nut 14, and the body portion 11 and the flange portion 12 are provided with a fluid inlet and an outlet. A spherical valve body 20 is rotatably arranged via a seat 15 between an inlet and an outlet inside the valve body 10. An engagement groove 22 is provided on the upper spherical surface of the spherical valve body 20, and an engagement piece 32 provided at the lower end of the stem 30 is fitted into the engagement groove 22. The stem 30 is rotatably supported by the main body 11 via a bearing 34, and is rotationally driven by a manual handle or an automatic drive device (not shown). The engaging piece 32 is the stem 30
Is a flat fan-shaped body extending orthogonally to the axis of the two flat contact surfaces 33, 33, and the two flat contact surfaces 33, 33 are formed in an arc surface symmetrical with respect to the center in the longitudinal direction. The engagement groove 22 is a flat fan-shaped groove having two parallel flat contact surfaces 23, 23 each having a width equal to or slightly wider than the width between the two flat contact surfaces of the engagement piece 32.
When the engagement piece 32 is fitted in the engagement groove 22, the two planar contact surfaces 23, 23 and the two arc-shaped contact surfaces 33, 33 make linear contact with each other.

As shown in FIG. 3, due to an error in manufacturing and assembling, the axis A2 of the spherical valve body 20 is inclined with respect to the axis A2 of the stem 30. However, the two contact surfaces 23 of the engagement groove 22 are inclined so as to roll on the two contact surfaces 33 of the engagement piece 32, so that the axial center A2 of the spherical valve body 20 is increased.
Since it intersects with the axis A1 of the stem 30 at the center of the engaging piece 32, the stem 30 is not twisted laterally even if the spherical valve body 20 is tilted. Further, even if the stem 30 is rotated in this state, the flat contact surface 23 of the engagement groove 22 can slide along the arcuate contact surface 33 of the engagement piece 32. Therefore, the rotation resistance of the stem 30 is not so great as compared with the case where the axial center of the spherical valve body 20 is not displaced, and it can be said that an excessive force is less likely to act on the seat.

As shown in Fig. 5, when the valve is closed, the spherical valve body is generated by the fluid pressure.
The axis A2 of 20 is offset from the axis A1 of the stem 30. Then, when the stem 30 is rotated, the same state as in FIG. 3 is obtained, so that the stem 30 is not twisted and the spherical valve body 20 is not swung by the stem 30.

[Advantages of the Invention] As described above, the ball valve of the present invention is different from the conventional one in which the engagement valve of the stem and the engagement groove of the spherical valve element are in flat contact with each other, and thus, the slip valve has a flat surface and an arc surface. Due to the line contact, even if the spherical valve element is displaced from the stem axis center due to manufacturing and assembly errors or fluid pressure, the stem will not be twisted in the lateral direction, and the spherical valve element will not move to the stem axis center. Even if the stem is rotated in a state of being displaced with respect to it, the spherical valve body rotates about its axis without being swung. Therefore, even if the stem and the spherical valve disc are misaligned with each other, the required rotational torque of the stem is not significantly increased, and there is no fear that unreasonable force acts on the seat to reduce durability. The effect is obtained.

In particular, in the case of an automatic valve, a relatively large and expensive drive unit has been provided so far in consideration of the deviation of the spherical valve body with respect to the axial center of the stem, but according to the present invention, the drive unit can be made small and inexpensive. Since it can be changed, the special effect of significantly reducing the cost can be obtained.

[Brief description of drawings]

1 and 2 are cross-sectional views of a ball valve according to an embodiment of the present invention. FIG. 1 shows a valve open state, and FIG. 2 shows a valve closed state. FIG. 3 is an exaggerated schematic view showing a state where the spherical valve body is displaced, FIG. 4 is an exaggerated schematic view showing a state where the spherical valve body of the conventional ball valve is displaced by fluid pressure, and FIG. It is a schematic diagram showing exaggeratedly a state where a stem is twisted. In the figure, reference numeral 10 is a valve body, 20 is a spherical valve body, 22 is an engaging groove, 23 is a contact surface, 30 is a stem, 32 is an engaging piece, and 33 is a contact surface.

Claims (1)

[Claims] 1. A valve body (10), a spherical valve body (20) rotatably installed in the valve body, and a stem (30) bearing on an upper spherical surface of the valve body, In a ball valve in which an engaging piece (32) integrally formed at the lower end of the stem is fitted into an engaging groove (22) provided on the upper spherical surface of the spherical valve body to rotate the spherical valve body by the stem. , The two contact surfaces (33) extending in the longitudinal direction of the engaging piece are formed in an arc shape whose cross section is bulged outward, and the two contact surfaces (23) extending in the longitudinal direction of the engaging groove are parallel to each other. A ball valve characterized by being formed into a flat surface so that they are in line contact with each other.