JPH07274472A - Direct acting stepping motor - Google Patents

Abstract

PURPOSE:To improve the reliability on a stopper pin at setting of initial position, and prevent the mutual bite of external thread and internal thread, and improve the precision of initial position, in a direct acting stepping motor. CONSTITUTION:The resin part 10 of a rotor is provided with a stopper piece 33 in contact with a stopper pin 12, and the stopper piece is fixed not only in the specified position from internal thread 10a but also in the specified position from the pole position of a magnet. A shaft 9 is provided with external thread, and a stopper pin 12 is fixed in the specified position from the position of the external thread, and the rotation of the rotor is stopped in the rotational direction by making the stopper piece 13 and the stopper pin 12 abut on each other by the energization of a stator 17, whereby the improvement of the reliability on the stopper pin 12, the prevention of the mutual bite of the external thread and the internal thread, and the improvement of the precision of initial position can be materialized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct drive type stepping motor having a stopper structure for effectively performing initial setting.

[0002]

2. Description of the Related Art In recent years, many direct-acting stepping motors have been used as actuators for automobiles in intake and exhaust systems of engines.

A conventional direct acting stepping motor will be described below. FIG. 12 is a sectional view of a conventional direct acting stepping motor. In FIG. 12, 1 is a shaft, and 2 is a resin portion of a rotor having a male screw 1a, and 2 is a female screw 2a. A stopper pin 4 is fixed to the shaft 1. Reference numeral 5 is a bearing metal composed of an oil-impregnated bearing or the like, which holds the shaft 1 slidably, and a D-cut portion is provided on the shaft 1, and a hole having a shape corresponding to the D-cut portion is provided to hold the shaft 1 in a non-rotating state. is doing. 6a and 6b are ball bearings, and 6a is press-fitted and fixed to the bearing metal 5 to form a female screw 2a.
Holding one of the resin portions 2 of the rotor having 6 mm, and 6b is press-fitted and fixed to the other of the resin portions 2 of the rotor having the female screw 2a. Reference numeral 7 is a bracket into which the bearing metal 5 is press-fitted and holds the ball bearing 6 a through the bearing metal 5. Reference numeral 8 denotes a stator which, when energized, generates a rotating magnetic field to rotate the magnet 3.

The operation of the direct-acting stepping motor constructed as above will be described below. First, when the stator 8 is energized, a rotating magnetic field is generated, the magnet 3 rotates, and at the same time, the resin portion 2 of the rotor having the female screw 2a holding and fixing the magnet 3 also rotates, and the female screw 2a and the male screw 1a of the shaft 1 rotate. Through shaft 1
Is linearly moved to bring the stopper pin 4 into contact with the end surface of the bearing metal 5 to set the initial position.

[0005]

However, in the above-mentioned conventional structure, since the rotary motion of the magnet 3 is converted into the linear motion and transmitted to the shaft 1 via the male screw 1a and the female screw 2a of the shaft 1, the stopper is used. Since the force when the pin 4 is brought into contact with the end surface of the bearing metal 5 is amplified, the problem of reliability of the stopper pin 4 and the magnet 3
Since the linear motion is stopped by the stopper pin 4 that has converted the rotational motion of the male screw into the linear motion, the male screw 1a becomes the female screw 2a.
There was a problem that it was difficult to get together and bite each other.

The present invention solves the above-mentioned conventional problems, and provides a direct-acting stepping motor for improving the reliability of the stopper pin, preventing the male and female screws from biting, and improving the accuracy of the initial position. The purpose is to

[0007]

In order to achieve this object, a direct-acting stepping motor according to the present invention has a stopper pin fixed to a shaft having a male screw, and a stopper piece with which the stopper pin abuts in a rotational direction is a rotor. It is fixed to the rotor and has a structure for stopping the rotation of the rotor itself. Also, female screw position of rotor and stopper piece fixing position, male screw position of shaft and stopper pin fixing position,
The configuration is such that the female screw position of the rotor and the pole position of the magnet are set to predetermined positions.

[0008]

With this structure, the stopper pin abuts the stopper piece in the rotation direction and stops the rotation of the rotor, so that the stopper pin has to withstand the force due to the rotation torque of the rotor, and is more effective than the force converted into the linear motion. Since it is much smaller, the reliability of the stopper pin can be improved, and the rotation of the rotor itself can be stopped, preventing biting of the male screw and female screw, the female screw position of the rotor and the stopper piece fixing position, the male screw position of the shaft and the stopper pin fixing position. ，
By setting the female screw position of the rotor and the pole position of the magnet to predetermined positions, the stopper pin and the stopper piece are always in contact with each other at the same position, so that the accuracy of the initial position can be improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a direct acting stepping motor according to an embodiment of the present invention, FIG. 2 is a front view of a shaft of the stepping motor, FIG. 3 is a detailed view of the shaft of the stepping motor and a male screw, and FIG. 5 is a front view of a stopper piece of the stepping motor, FIG. 6 is a sectional view of the stopper piece of the stepping motor, FIG. 7 is a left side view of a rotor of the stepping motor, and FIG. 8 is a sectional view of the rotor of the stepping motor, FIG. 9 is a right side view of the rotor of the stepping motor, FIG. 10 is a detailed view of a female screw portion of the stepping motor,
FIG. 11 is a sectional view of a rotor assembly of the stepping motor.

In FIGS. 1 to 11, reference numeral 9 denotes a shaft having a male screw 9a. A stopper pin 12 is fixed to the shaft 9 at a predetermined position from the male screw 9a.
Reference numeral 13 is a stopper piece, 10 is a resin portion of a rotor having a female screw 2a, and 11 is a magnet. Stopper piece 13
Is fixed to the concave portion 10b of the resin portion 10 of the rotor so as to be located at a predetermined position from the female screw 10a. Magnet 1
1 has a concave portion 11a indicating the pole position of magnetization.

The magnet 11 is held by the resin portion 10 of the rotor so that the recess 11a and the stopper piece are located at predetermined positions.

A bearing metal 14 holds the shaft 9 in a slidable but non-rotatable state. 15a,
15b is a ball bearing, 15a is a bearing metal 14
And one of the resin parts 10 of the rotor having the female screw 10a is held, and 15b is press-fitted and fixed to the other resin part 10 of the rotor having the female screw 2a. Reference numeral 16 denotes a bracket, into which the bearing metal 14 is press-fitted.
The ball bearing 15a is held via. 17
Is the stator.

The operation of the direct-acting stepping motor constructed as above will be described. First, when the stator 17 is energized, a rotating magnetic field is generated, and the magnet 1
1 rotates and has resin portion 10 of rotor having female screw 10a
Also rotates at the same time.

By the rotation of the female screw 10a, a rotational force is transmitted to the male screw 9a of the shaft 9, and the shaft makes a reciprocating linear motion.

When the shaft 9 moves in the exit direction, the female screw 1 is attached to the stopper pin 12 fixed to the shaft 9.
The stopper piece 13 fixed to the resin portion 10 of the rotor having 0a abuts, the rotation of the magnet 11 stops, and the movement of the shaft 9 also stops.

As described above, according to the present embodiment, the stopper piece 13 is fixed to the resin portion 10 of the rotor having the female screw 10a which rotates simultaneously with the magnet, and the female screw 10a is formed.
Is set to a predetermined position from the magnetized pole position of the magnet 11, and the stopper pin 12 is fixed to the shaft 9 from the position of the male screw 9a to a predetermined position. The force when the pin 12 abuts on the stopper piece 13 can be reduced, the bite between the male screw 9a and the female screw 10a of the shaft 9 can be prevented, and the shaft 9 can be ejected when the stopper pin 12 and the stopper piece 13 abut. The dimensional accuracy can be improved.

[0018]

As described above, according to the present invention, the stopper pin 12 is fixed to the shaft 9 and the stopper piece 13 is fixed to the resin portion 10 of the rotor having the female screw 10a. That can reduce the force when it abuts against the screw, prevent the male screw 9a and the female screw 10a from biting, and realize an excellent direct-acting stepping motor that can improve the initial position accuracy of the shaft 9. Is.

[Brief description of drawings]

FIG. 1 is a sectional view of a direct acting stepping motor according to an embodiment of the present invention.

FIG. 2 is a front view of a shaft of a direct acting stepping motor according to an embodiment of the present invention.

FIG. 3 is a detailed view of a shaft and a male screw of a direct acting stepping motor according to an embodiment of the present invention.

FIG. 4 is a front view of a shaft assembly of a direct acting stepping motor according to an embodiment of the present invention.

FIG. 5 is a front view of a stopper piece of a direct acting stepping motor according to an embodiment of the present invention.

FIG. 6 is a sectional view of a stopper piece of a direct acting stepping motor according to an embodiment of the present invention.

FIG. 7 is a left side view of a rotor of a direct acting stepping motor according to an embodiment of the present invention.

FIG. 8 is a sectional view of a rotor of a direct acting stepping motor according to an embodiment of the present invention.

FIG. 9 is a right side view of the rotor of the direct acting stepping motor according to the embodiment of the present invention.

FIG. 10 is a detailed view of a female screw portion of a direct acting stepping motor according to an embodiment of the present invention.

FIG. 11 is a sectional view of a rotor assembly of a direct acting stepping motor according to an embodiment of the present invention.

FIG. 12 is a sectional view of a conventional direct acting stepping motor.

[Explanation of symbols]

 1,9 Shaft 1a, 9a Male screw 2,10 Rotor resin portion 2a, 10a Female screw 3,11 Magnet 4,12 Stopper pin 5,14 Bearing metal 6a, 6b, 15a, 15b Ball bearing 7,16 Bracket 8,17 Stator 11a recess 13 stopper piece

Claims (4)

[Claims] 1. A shaft having a male thread and slidably supported, and a rotor arranged coaxially with the shaft and having a female thread on an inner peripheral portion of a magnet. The male thread of the shaft and the rotor of the rotor are provided. In a stepping motor in which a female screw is screwed and the rotational motion of the rotor is converted into a linear motion through the female screw of the rotor and the male screw of the shaft by energizing the stator winding, a stopper pin is provided on the shaft. A direct-acting stepping motor, characterized in that it is fixed at a position perpendicular to the axis of the shaft, and a stopper piece is fixed to the rotor in contact with the stopper pin in the rotational direction to define the shaft extension dimension. 2. The direct acting stepping motor according to claim 1, wherein the stopper piece fixing position is set to a predetermined position from the female screw position of the rotor. 3. The direct acting stepping motor according to claim 1, wherein the stopper pin fixing position is set to a predetermined position from the male screw position of the shaft. 4. A direct-acting stepping motor according to claim 1, wherein the position of the female screw of the rotor and the pole position of the magnet of the rotor are set to predetermined positions for magnetization.