Flow Control Valve Apparatus

The present invention relates to a solenoid motor wherein a rotating magnet connected to a torsion bar effects an angular displacement in such a manner that an electromagnetic force for rotating the magnet is equal to a torsional spring force in the torsion bar.

A flow control valve is well known, wherein said valve provided with an actuator of a rotary solenoid types, wherein the degree of rotation of a shaft is in proportion to an electric current applied thereto. In this type of solenoid motor, which has been recently developed, a hollow shaft is rotatably supported on a housing. A torsion bar, such as a stainless steel wire, passes through the hollow shaft. The torsion bar has a first end connected to the body adjacent to one end of the hollow shaft and a second end connected to the other end of the hollow shaft. An electro-magnetic force is generated in the hollow shaft for rotating the shaft against the torsional spring force in the torsional bar. Thus, the angular position of the shaft is controlled by changing the electro-magnetic force, so that the degree of the opening of a valve unit connected to the shaft can be controlled.

In the known rotary type of solenoid, the ends of the torsion bar are provided with split sleeves of a tapered shape for fixing the ends of the torsion bar. Each of the ends of the torsion bar is inserted to one end of the shaft or the housing, respectively, so that each sleeve effects fixation of the corresponding end of the torsion bar under a wedge action. However, the prior art connection suffers from a drawback in that it is difficult to maintain the desired effective length of the bar, so that a variation of such length is apt to occur between the valve devices. Due to the variation of the length of the torsion bar, a variation in the spring coefficient is generated, so that a single flow characteristic is not maintained between the valve devices.

An object of the present invention is to provide a solenoid motor with means for reliably fixing a torsion bar while easily maintaining the disired length of the torsion bar.

According to the present invention, a solenoid motor for effecting a limited angular rotational movement of a member connected to the solenoid motor is provided, comprising:

a housing assembly,

a shaft adapted to be connected to said member,

means for rotatably supporting the shaft to the housing,

a torsion bar for generating a torsional force causing the shaft to be rotated, and

means for generating an electro-magnetic force opposite to the torsional force, the shaft and the housing having a pair of axially spaced apart crimped portions for fixedly connecting an end of the torsion bar to the shaft and for fixedly connecting the other end of the torsion bar to the housing.

FIG. 1 is a cross-sectional view of a valve apparatus incorporated with a solenoid motor according to the present invention.

FIG. 2 is a bottom elevational view of the valve apparatus in FIG. 1.

FIG. 3 is a bottom elevational view of the valve aparatus in FIG. 1.

FIG. 4 is a diagrammatical view showing a principle of the rotary solenoid motor accordings to the present invention.

FIG. 5 shows a relationship between the electric current and the amount of flow in the valve apparatus.

FIG. 6 is a perspective view of an end of a torsion bar fixed with a crimp, according to the present invention.

FIG. 7 shows the cross section of the torsion bar in FIG. 6.

FIG. 8 is a perspective view of another way of fixing the crimp around a torsion bar.

FIGS. 9 through 11 are elevational views showing the various alternative shapes of crimps arranged around a torsion bar.

In FIGS. 1, 2 and 3, a reference numeral 1 indicates a tubular valve housing which rotatably suports a valve rotor 3. An inlet pipe 5 and an outlet pipe 7 are fixedly connected to the valve housing 1 so that they are in communication with valve ports 1a and 1b, respectively formed in the valve housing in a diametrically opposed relationship. The valve rotor 3 contains diametrically opposed openings 3a and 3b which are always in communication. An effective flow area of the openings 3a and 3b is changed in accordance with the angular position of the rotor 3, so that the amount of flow of fluid directed from the inlet pipe 5 to the outlet pipe 7 is controlled by rotating the rotor 3.

The valve rotor 3 is fixedly connected to a hollow shaft 11, which is provided with a pair of axially spaced apart bearing units 13 and 15 for attaining the rotation of the shaft 11. The bearing unit 13 is press fitted to the housing 1. The bearing unit 15 is press fitted to an end plate member 19, which is fixedly connected to the housing 1 by means of bolts 17. A torsion bar 21, in this case a fine stainless steel wire, extends through the hollow shaft 11. As will be fully described later, the torsion bar 21 is, at one end, connected to the upper end of the shaft and is, at the other end, connected to projection 19a of the end plate 19. The torsion bar 21 produces a torsional resilient force for urging the hollow shaft 11, i.e., the valve rotor 3, toward an initial angular position. As shown in FIG. 3, the end plate 19 has angularly spaced arc-shaped slits 19c, through which the bolts 17 are inserted. Thus, a limited angular adjustment of the plate 19 can be effected when the bolts are loosened.

The apparatus includes a solenoid motor comprising laterally spaced coils 25 and 27 wound on bobbins 22 and 24, respectively. A rotating permanent magnet 31 is press fitted to the shaft 11, so that it is located between the coils 25 and 27. As shown in FIG. 4, the rotating magnet 31 has at its diametrically spaced positions opposite poles N and S. The coils 25 and 27 are connected to an electric source via electrical wires 33 and 35, respectively. When an electrical current is supplied to the coils, facing sides of the coils are magnetized in opposite directions. Thus, the coils 25 and 27, together with the rotating permanent magnet, compose a two pole electrical motor wherein an electro-magnetic force is generated for rotating the magnet 31, until the electromagnetic force is equalized to the torsional force of the bar. Thus, the angular position of the magnet 31 is changed in accordance with the value of the electrical current directed to the coils 25 and 27. For example, the rotor may be rotated between the positions a and b. As a result of this, the effective flow area, which corresponds to the amount of fluid passed through the valve, may be controlled in accordance with the value of the electric current.

According to the present invention, the torsion bar 21 generating a torsional force in the hollow shaft 11 opposite to the electro-magnetic force has an upper caulked end for fixedly connecting the shaft 11 with the upper end of the torsion bar 21. The end plate 19 connected to the housing 1 has a tublar projection 19a located in the lower end of the shaft. The tubular projection 19a is provided with an upper crimped end for fixedly connecting the end plate 19 with the lower end of the torsion bar 21. As shown in FIG. 6, the crimped end of the shaft 11 or the projection 19a forms, in cross section, a regular polygonal shape, such as a hexagonal shape. Thus, a uniform force is applied to the torsion bar for connecting it to the shaft or the end plate.

As a result of the crimp around of the torsion bar, a length (l) of the torsion bar 21 is easily maintained at a predetermined constant value. Thus, no variation in the curve, as shown in FIG. 5, is generated. It should be noted that a small change of the length l causes a relatively large change in the torsional coefficient, since the torsion bar is rotated at a very limited angle, such as 60.degree..

Thus, variation in the length l should be surpressed, which is accomplished in the present invention.

In addition, the crimped portion forms a regular polygonal shape, so that it is uniformly engaged at the periphery of the bar 21. Thus, local deformation or concentration of stress is prevented.

It should be noted that in place of arranging the torsion bar in the shaft, it may be arranged outside of the shaft, so that the torsion bar is connected in series with respect to the shaft.

In FIG. 8 the crimped portion forms a regular rectangular shape.

In FIG. 9, the crimped portion forms an hexagonal shape, having apexes outwardly projected, which are inevitably generated during the manufacturing process. In FIG. 10, the crimped portion forms a polygonal shape having convex sides.

In FIG. 11, the crimped portion forms a polygonal shape having concave sides. Outwardly extended projections may be formed on the apex.

While the present invention is described with reference to the attached drawings, many modification and change may be made by those skilled in this art without departing from the scope of the present invention.