JPH0235095Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention is particularly applicable to electric valves that control flow rate by converting the rotational motion of a motor into linear motion of the valve stem.
Improvement of the mechanism that accurately stops the linear movement of the valve stem at a preset valve stem position before clamping friction force is generated on the threaded part formed by small pitch threads such as JIS fine threads and JIS coarse threads. It is related to.

[Conventional technology]

Fig. 1 shows a conventional motor-operated valve rotation prevention structure that was filed by the applicant in Utility Model Application No. 15360/1983. 3. The male thread 4, the motor rotor 5, and the bearing end 6 are integrally formed in this order, and the male thread 4
is fitted with a propulsion bearing 9 which is fixed to the valve body and has a female thread 8 cut in the center, and the bearing end 6 is fitted with a bearing 11 which is fixed within a case 10 made of a non-magnetic material.

The case 10 is airtightly integrated with the valve body 7 having fluid inlets and outlets 13 and 14 and the valve seat 2 by plasma welding or the like.
0, a stator coil 12 of the motor is fixed at a position corresponding to the rotor 5 of the motor.

Further, on the valve shaft 1, fixing pins 15, 16 are fixed by a method such as press fitting at a distance from both ends of the male thread 4, and the fixing pins 15, 1
Round pin-shaped stopper 17 that limits the rotation of 6
was fixed through the propulsion bearing 9.

Next, the operation of the conventional electric valve will be explained.

When the stator coil 12 of the motor is energized, the rotor 5 rotates, and the valve shaft 1 rotates and moves forward (in the valve-closing direction) or backward (in the valve-opening direction) by the screw action of the male thread 4 and the female thread 8.

When closing the valve, in order to prevent the valve part 3 from digging into the valve seat 2, which would make the valve opening movement impossible, a very small gap should be placed between the valve part 3 and the valve seat 2. The stop pin 16 and the pin-shaped stopper 17 come into contact with each other at a valve stem position set to have a gap, thereby stopping the forward movement of the valve stem. Further, when opening the valve, the stop pin 15 and the stopper 17 come into contact with each other to stop the backward movement of the valve stem. Note that the pin-shaped stopper 17
is selectively inserted into one of the fixing holes 19 formed at equal angles on the surface of the propulsion bearing 9 shown in FIG. It has been adjusted to reduce the variation in

Further, the conventional stop pins 15 and 16 fixed to the valve shaft 1 side have a round cross-sectional shape as shown in FIG. 3.

Therefore, since the surfaces where the stop pins 15, 16 and the pin-shaped stopper 17 come into contact are curved surfaces, the stop pin 16 rotates once together with the valve shaft and moves from the position shown by the broken line in the figure to the position shown by the solid line ( In other words, if the distance △ between the right end of the pin-shaped stopper 17 and the left end of the stop pin 16 is larger than the radius d/2 (=diameter) of the stop pin and slightly smaller than the diameter, when If the length l of the abutting part between the stop pin and the stopper becomes smaller than the radius of the stop pin, the stop pin and stopper may become jammed when they come into contact, making it impossible for the valve to operate, or even causing the stopper to rotate one full rotation. As time passed, a similar fatal situation occurred in which the valves were no longer able to operate.

Therefore, one way to eliminate this drawback is to increase the screw pitch P as shown in Figure 4.
It is conceivable that the contact length l between the stop pin and the stopper is greater than or equal to the cross-sectional radius d/2 of the stop pin.

However, when a motor-operated valve is used as a proportional control valve, the amount of change in valve opening per revolution of the valve stem 1 becomes large, and the disadvantage is that the flow rate resolution, which is an important characteristic for a proportional control valve, becomes rough. occurs and is not practical.

The present invention is intended to solve the above-mentioned problems.In particular, the thread part 18 has a small thread pitch P such as a JIS fine thread or a small diameter JIS coarse thread.
In addition, the present invention provides an optimal method for improving the flow rate resolution of a valve by using a thread that can be easily machined.

[Means for solving problems]

The rotation stopper structure of the electric valve of the present invention is such that the stator 12 of the motor is energized to rotate the rotor 5, and the rotation is converted into linear motion of the valve shaft 1 by a screw provided in the propulsion bearing 9. Electric valve propulsion bearing 9
A stopper 17 is provided so as to protrude to both ends of the bearing, and stop pins 15 and 16 are provided on the valve stem 1 at a distance from both ends of the male thread 4, respectively.
In a motor-operated valve in which the amount of movement of the valve shaft is regulated by bringing the retaining pins 15, 16 into contact with the stopper 17, the propulsion bearing 9 of the motor-operated valve is provided with pins that protrude toward both ends of the bearing. A stopper 17 having a shape is provided, and the thread pitch of the male thread 4 formed on the valve stem 1 is as follows.
For example, it is formed into a thread with a small pitch such as a JIS fine thread or a JIS coarse thread, and on the other hand, the cross-sectional shape of the retaining pins 15 and 16 fixed to the valve stem 1 is rectangular, and one surface thereof is aligned with the axis of the valve stem 1. This is characterized by the fact that the two sides are parallel to each other.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 5 shows a state in which the stop pin 16 and the stopper 17 are in contact with each other.

The propulsion bearing 9 of the electric valve is provided with pin-shaped stoppers 17 that protrude from both ends of the bearing.

On the other hand, the valve shaft 1, which moves linearly forward or backward while rotating, has a male thread 4 formed with a small pitch, such as a JIS fine thread or a JIS coarse thread.

Also, a stop pin 15, 1 fixed to the valve shaft 1 is provided.
The cross-sectional shape of the valve 6 is a square or a rectangle, and one surface that contacts the stopper 17 is parallel to the axis of the valve shaft 1.

The inner diameter of the hole 20 provided on the valve shaft is slightly smaller than the diagonal length of the rectangular stop pin, and the stop pin 16 is fixed in this hole 20 by press fitting.

[Effect of idea]

In the present invention, the cross-sectional shape of the stop pins 15 and 16 that come into contact with the pin-shaped stopper 17 is square or rectangular, and the contact portion with the stopper 17 is in surface contact. There is no slippage or galling when the stop pin 16 and stopper 17 come into contact, and the amount of linear movement of the valve stem 1 per revolution can be as small as 1 mm by using, for example, a JIS coarse thread M6 x P1.0. , which has high practical value as it allows the production of a motor-operated valve with high flow rate resolution at low cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view showing an example of the configuration of an electric valve. FIG. 2 is a perspective view of the propulsion bearing. Figures 3 and 4
The figure is an explanatory diagram showing a contact state between a pin and a stopper in a conventional rotation stopper structure. FIG. 5 is an explanatory diagram showing a state in which a stop pin and a stopper are in contact with each other in the rotation stopper structure of the present invention. 1...Valve stem, 2...Valve seat, 3...Valve part, 4...
Male thread, 5...Motor rotor, 6...Bearing end,
7...Valve body, 8...Female thread, 9...Propulsion bearing,
10... Case, 11... Bearing, 12... Motor stator coil, 13, 14... Fluid inlet/outlet,
15, 16...stop pin, 17...stopper, 1
9... Fixing hole, 20... Hole for fixing the stop pin.

Claims (1)

[Claims for Utility Model Registration] An electrically operated valve in which the stator 12 of the motor is energized to rotate the rotor 5, and the rotation is converted into linear motion of the valve shaft 1 by a screw provided in the propulsion bearing 9. A stopper 17 is provided on the propulsion bearing 9 so as to protrude to both ends of the bearing, and stopper pins 15 and 1 are provided on the valve shaft 1 at a distance from both ends of the male thread 4, respectively.
6 is provided, and the movement of the valve stem is regulated by bringing the stop pins 15, 16 into contact with the stopper 17. A pin-shaped stopper 17 is provided so as to protrude, and the thread pitch of the external thread 4 formed on the valve stem 1 is as follows.
For example, it is formed into a thread with a small pitch such as a JIS fine thread or a JIS coarse thread, and on the other hand, the cross-sectional shape of the retaining pins 15 and 16 fixed to the valve stem 1 is rectangular, and one surface thereof is aligned with the axis of the valve stem 1. A rotation stopper structure for an electric valve, characterized in that the motor-operated valves are parallel to each other.