JPS6330215Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention involves inserting a movable spindle into the rotor, rotating the rotor to move the movable spindle in the axial direction using a screw feed method, and moving the movable spindle to move the movable spindle in the axial direction. The present invention relates to a stop structure for stopping a moving main shaft at a front-rear stop position in a pulse motor that controls, for example, a valve.

Conventionally, this type of pulse motor has the following structure in order to stop the movable main shaft at the front and rear stop positions.

That is, a small diameter part is formed in the middle part of the cylindrical rotor main body, an internal thread is provided on the inner periphery of the small diameter part, and a plurality of through holes are provided in the small diameter part along the axial direction, and each of the through holes is provided in the small diameter part. A metal pin is inserted into the hole so that its both ends protrude from both end faces of the small diameter portion, and stopper plates each having a protrusion are provided on both sides of the movable main shaft that is screwed into the small diameter portion, and the protrusion and the above The rotation of the rotor is stopped by engagement with the protruding end of the pin, thereby stopping the movement of the movable main shaft.

The present invention reduces manufacturing man-hours and the number of parts by making it possible to reliably stop the moving spindle at a predetermined stop position without providing a through hole in the small diameter portion of the moving spindle or using a metal pin. This is what we are trying to achieve.

In order to achieve the above purpose, in this invention,
Stopper surfaces are formed at both ends of the thread of the outer peripheral screw of the movable spindle, while stopper surfaces of the screw of the movable spindle are formed on both sides in the axial direction of the rotor that accommodates the movable spindle at the front and rear movement stop positions of the movable spindle. A stopper is provided that comes into contact with the surface.

The present invention will be described in detail below with reference to the illustrated embodiments.

FIG. 1 shows a state in which a moving shaft 4 is inserted through a rotor R of a pulse motor. As shown in this figure,
The rotor R has a reinforcing metal sleeve 3 fitted and fixed on the outer periphery of a roughly cylindrical resin rotor body 2, and a cylindrical ferrite magnet 1 fixed on the outer periphery of the sleeve 3. It has a structure in which stopper plates 5a and 5b are fixed to both sides of the main body 2, and the rotor R is reversibly rotatably housed in a motor housing (not shown), and a stator (not shown) is arranged around it. It's becoming like that.

Each of the stopper plates 5a and 5b has a hole 5d in the center thereof through which the moving main shaft 4 passes, and two protrusions each having a stopper surface 5e above and below the through hole 5d, as best shown in FIG. A shaped stopper 5c is formed.

Further, the rotor main body 2 has a small diameter portion 2a at an intermediate portion of its inner surface, and an inner circumferential thread 2b is formed on the inner surface of this small diameter portion 2a.

On the other hand, the moving main shaft 4 has a central shaft 4a and a central shaft 4a.
The outer shaft 4b has a large diameter part 4c in the middle thereof, and the inner peripheral thread of the rotor body 2 is attached to the outer periphery of the large diameter part 4c. Two outer peripheral screws 4d, 4 that are screwed together with 2b.
It has e. The movable main shaft is supported by a motor casing (not shown) so as to be movable in the axial direction but not rotatable. However, the rotor R
When the main shaft 4 rotates in both forward and reverse directions, the moving main shaft 4 reciprocates in the front and rear directions.

By the way, both ends of the large diameter portion 4c of the movable main shaft 4 are arranged as shown in FIGS. 3 and 4. That is, the thread ends of each screw 4d, 4e are cut off to form stopper surfaces 4f, 4g. These two stopper surfaces 4f and 4g are located on exactly opposite sides. These stopper surfaces 4f, 4g
cooperates with each stopper surface 5e of each stopper plate 5a, 5b, and when the rotor R rotates, therefore, each stopper plate 5a, 5
b rotates and the movable main shaft 4 comes to either the front or rear stop position, each stopper plate 5a or 5
The stopper surface 5e of the stopper 5c in FIG. b comes into contact with one of the stopper surfaces 4f and 4g of the movable main shaft 4, and the rotation of the rotor R is stopped.

According to the above embodiment, the stopper surfaces 4f, 4g of the moving main shaft and the stopper plates 5a, 5b
Since the stopper 5c is small in size, it has the advantage of being extremely easy to work with, but it cannot be denied that the strength against the impact force generated at the time of a collision is somewhat weak. In order to increase this strength, the embodiments shown in FIGS. 5, 6, and 7 are effective.

In the embodiment shown in FIG. 5, a stopper extending in the radial direction is formed by cutting both end surfaces of the large diameter portion 4c of the movable main shaft 4 forward of each end of the screws 4d and 4e along the spiral of the screw. A stopper 5c' is formed on the inner surface of each stopper plate 5a, 5b and has a stopper surface 5e' extending in the radial direction. The stopper surfaces 4f', 4g' of the movable main shaft 4 and the stopper plate 5
It is sufficient that the stopper surfaces 5e' of a and 5b are approximately along the axial cross-section, but as shown in FIG. 6, the stopper surfaces 4f', 4g'; It would be better if they were tilted so that the contact area between the two was increased. If you do this,
Since the impact force per unit area of each stopper surface 4f', 4g';5e' is reduced, the durability of the stopper surface is increased. It goes without saying that making the stopper surface perpendicular to the spiral direction of the screw in this way can also be applied to the embodiments shown in FIGS. 1 to 4.

In each of the embodiments shown in Figs. 1 to 4, Fig. 5, and Fig. 6, the material of the movable main shaft 4 is not specified, but in order to reduce the weight of the motor, it is necessary to It is preferable that a portion be made of resin.

FIG. 7 shows an embodiment in which the outer shaft 4b of the movable main shaft 4 is made of resin. In this case, the central axis 4
Preferably, a is made of metal in order to compensate for the strength of the entire moving main shaft 4. In addition, in this case, if the stopper plates 5a, 5b are made of metal, in order to withstand the impact on the metal stopper,
As shown in FIG. 7, it is preferable to abut and fix a metal cover 6 to the end surface of the large diameter portion 4c of the resin outer shaft 4b. In Fig. 7, the resin outer shaft 4
The structure and formation of b is the same as that of the outer shaft 4b shown in FIG. The cover 6 has a shape that matches the end face shape of the large diameter portion 4b. That is, a center hole 6a into which the central shaft and a part of the outer shaft 4b are inserted is formed in the center, and a stopper surface 6 that comes into contact with the stopper surfaces 4f' and 4g' on the end surface of the large diameter portion 4b is formed.
b, 6c are formed. In this example,
Stopper 5 of each stopper plate 5a, 5b
c comes into contact with each stopper surface 5e' of this cover 6 when the rotor is stopped.

The present invention can be implemented in various ways other than the above-mentioned embodiments. For example, the outer circumferential thread of the movable main shaft may be a single-thread thread or a thread with three or more threads.

As specifically explained in the embodiments above, according to the stop structure of the movable spindle in a pulse motor according to the present invention, each end of the outer circumferential screw provided on the outer periphery of the movable spindle is used to form a stopper surface. Therefore, the number of man-hours required when a through hole is formed in the rotor body and a metal pin is inserted into the through hole as in the conventional example described above is not required, and therefore manufacturing costs can be reduced. . It is easily possible to specially provide protruding stoppers on both end faces of the large diameter portion of the moving main shaft, but in this case, since the protruding stoppers are structured to protrude from both end faces of the large diameter portion, the amount of 1 It is necessary to widen the distance between the pair of stopper plates, which causes problems such as enlargement of the rotor to some extent, which is beyond the scope of the present invention.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a sectional view showing a state in which the moving main shaft is installed in the rotor of a pulse motor, Fig. 2 is a perspective view of the stopper plate in Fig. 1, and Fig. 3 , 4 are end views and front views of the movable spindle in FIG. 1, FIG. 5 is an exploded perspective view of a stopper plate and the movable spindle according to another embodiment, and FIG. 6 is a further embodiment according to another embodiment. FIG. 7 is a front view of the stopper plate and the moving main shaft, and an exploded perspective view of the cover and the moving main shaft according to still another embodiment. R...Rotor, 2b...Inner circumference screw, 4...Moving main shaft, 4c...Large diameter section, 4d, 4e...Outer circumference screw, 4f, 4f', 4g, 4g'...Stopper surface,
5a, 5b...stopper plate, 5c, 5
c'...stopper, 5e, 5e'...stopper surface.

Claims (1)

[Claims for Utility Model Registration] (1) A movable main shaft having an outer circumferential thread is screwed into a rotor that is approximately cylindrical and has an inner circumferential thread on its inner circumferential surface, and is moved by the rotation of the rotor. In a pulse motor in which the main shaft can be moved in the axial direction, both ends of the thread of the outer circumferential screw of the moving main shaft are cut off to form stopper surfaces, and both ends of the rotor in the axial direction that house the moving main shaft are cut off. A stop structure for a movable spindle, characterized in that a stopper is provided that comes into contact with each stopper surface of the screw of the movable spindle at the front and rear movement stop positions of the movable spindle. (2) A large diameter portion is formed at the intermediate portion of the movable main shaft, and the outer circumferential thread is formed on the outer periphery of the large diameter portion, and further forward from each end of the thread on both end faces of the large diameter portion. The movable main shaft is inserted into both sides of the rotor, while the sides are cut along the spiral of the screw to form stopper surfaces extending from each end of the screw thread in the axial direction and roughly along the axial cross section. The utility model according to claim 1, characterized in that a stopper plate is provided, and a stopper is formed on the inner surface of the stopper plate, and has a stopper surface extending in the radial direction and substantially along the axial cross section. Stop structure for the moving spindle. (3) The utility model registered in claim 1 is characterized in that both the stopper surface of the movable main shaft and the stopper surface of the stopper plate are substantially perpendicular to the helical direction of the screw. Stop structure of the moving spindle described.