JPH0640448Y2 - Linear motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The invention of this application relates to a linear motor, and more specifically, to a configuration of a bearing of the linear motor.

(Prior Art) Regarding a conventional linear motion stepping motor,
A description will be given with reference to the attached FIG. 4 and FIG.

This type of stepping motor rotates the rotor R stepwise at a predetermined angle by controlling the current flowing in the coil 11 housed in the stator yoke 5. The rotor R is composed of a rotor collar 6 having a shaft 3 housed therein and a magnet M provided on the outer periphery thereof. The magnet M is provided opposite to the coil 11. Since the rotor color 6 is integrated with the magnet M by adhesion or insert molding, the rotor color 6 and the magnet M can rotate simultaneously. The shaft 3 comprises a non-cylindrical front portion 3a and a cylindrical rear portion 3b, and a lead screw 2 which is a male screw is formed on the outer periphery of the rear portion 3b.

The front portion 3a of the shaft 3 is fitted in a non-cylindrical groove h formed in the rotor collar 6, and the rear portion 3b is fitted in a cylindrical groove g. Since the outer peripheral surface f of the front portion 3a of the shaft 3 is formed in a D-cut shape on both sides, it can be fitted into the non-cylindrical groove h of the rotor collar 6 having the same shape.

The front portion 3a of the shaft 3 is supported by a mounting fixing plate 10 mounted on one side surface of the stator yoke 5 and a bearing 7 fitted and fixed, and the rear portion 3b of the shaft 3 is mounted on the other side surface of the stator yoke 5. It is supported by the nut 1 fitted and fixed to the mounting plate 4 and the bearing 8 fitted in the nut 1. To provide the nut 1, the screw 1a is screwed onto the male screw lead screw 2 provided on the outer periphery of the shaft rear portion 3b. A ball b is attached to the end of the shaft rear portion 3b.

When the coil group 11 is energized and controlled, the rotor color 6 of the rotor R rotates together with the magnet M integrated with it by a predetermined angle. This rotation is transmitted to the shaft 3, and by the screwing of the female screw 1a of the nut 1 fixed to the mounting plate 4 of the stator yoke 5 and the male screw lead screw 2 provided on the outer periphery of the rear portion 3b of the shaft 3, The front part 3a of the shaft 3 having the outer peripheral flat surface f of the D-cut shape on both sides slides in the groove h of the same shape of the rotor collar 6 in the axial direction. As a result, the shaft 3 can be displaced linearly in the axial direction.

However, the front portion 3a of the shaft 3 of the linear motor is supported by the bearing 7 because both sides thereof form flat surfaces f cut in a D shape, but the front portion 3a has a fourth surface between the bearing 7 and the bearing.
There is a gap 12 as shown in the figure. A spacer 9 having a hole larger than the outer shape of the front portion 3a is interposed between the bearing 7 and the rotor collar 6.

(Problems to be Solved by the Invention) In the conventional linear motor, a gap 12 is formed between the bearing 7 and the front portion 3a of the shaft 3, and a hole portion of the spacer 9 and the front portion 3a.
Since there is also a gap between and, there is a problem that unnecessary foreign matter enters into the inside through these gaps 12 and the like, causing a problem in the rotation of the rotor R.

The invention of this question is intended to solve the above problems, and means for achieving the object will be disclosed below.

(Means for Solving the Problems) The description will be made with reference to the reference numerals in the accompanying drawings used for describing the embodiments of the present invention.

The lead screw 2 provided on the outer circumference of the shaft 3 slidable in the grooves g and h provided on the rotor R and the nut 1 provided on the mounting plate 4 of the stator yoke 5 are screwed together according to the rotation of the rotor R. As a result, in the linear motor in which the shaft 3 can be displaced in the axial direction, the spacer 14 provided with the non-cylindrical hole of the shaft front portion 3a is provided between the end of the rotor collar 6 of the rotor R and the bearing 7. Half piece 13a of pole 13 formed by integrally forming half pieces 13a, 13a, which are interposed and arranged on the upper and lower flat surfaces of non-cylindrical portion 3a of the shaft, and spacer 14, respectively.
Is a gap formed by the bearing 7 and the non-cylindrical front shaft 3a
It is a linear motor characterized in that it is provided so that it can be inserted into 12 inside.

(Operation) The front shaft 3a is inserted into a spacer 14 provided with a non-cylindrical hole portion of the shaft front portion 3a between the bearing 7 and the rotor collar 6, or the bearing 7 and the non-cylindrical shape. Since the pole 13 provided on the outer periphery of the shaft 3a is fitted into the gap 12 formed with the front shaft 3a to close the gap 12, it is possible to prevent unwanted substances from entering from the outside.

(Embodiment) An embodiment of the present invention will be described below with reference to the accompanying drawings FIG. 1, FIG. 2 and FIG.

The niria motor of the embodiment of the present invention is different from the conventional one in the support structure of the front portion 3a of the non-cylindrical shaft and the bearing 7, but the other structures are the same. Therefore, the same members as those of the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the enlarged view of FIG. 2, the structure of the present invention is a collar-shaped spacer on the shaft front portion 3a between the bearing 7 and the rotor collar 6.
Insert 14 The spacer 14 is attached to the half-split pieces 13a, 13a arranged on the outer peripheral flat surfaces f of the shaft front part 3a, or is formed integrally with the half-split pieces 13a, 13a to form the cylindrical pole 13. . Attach this cylindrical pole 13 to the front of the shaft.
It is fitted into the gap 12 formed by 3a and the bearing 7.

Since the gap 12 is closed by the inserted pole 13, unnecessary substances such as dust are prevented from entering the rotor.

Next, as shown in FIG. 3, as another embodiment, the hole portion 15a of the collar-shaped spacer 15 may be formed in the shape of the non-cylindrical shaft front portion 3a. In this embodiment, the shaft 3a
Since both sides of the flat surface f are formed into a substantially oval shape, if the corresponding hole 15a is formed into an oval shape and is fitted into the shaft front portion 3a, only the spacer 15 can be externally attached. It is possible to prevent unnecessary substances from entering the inside of the rotor.

(Effect) According to the present invention, a spacer having a hole having a shape of the front portion of a non-cylindrical shaft is inserted between the bearing and the end portion of the rotor collar with the spacer fitted in the front portion. Alternatively, by inserting a pole that is adhered to or integrally formed with the spacer in the front portion into the gap formed by the front portion and the bearing, it is possible to prevent the intrusion of unwanted substances from the outside.

[Brief description of drawings]

FIG. 1 is a sectional view of a linear motor according to the present invention. FIG. 2 is an enlarged perspective view of a main part of FIG. FIG. 3 is an enlarged perspective view of a spacer according to another embodiment. FIG. 4 is a sectional view of a conventional linear motor. FIG. 5 is a side view seen from the direction of the arrow in FIG. f ... flat surface, g ... circular groove, h ... non-circular groove, M ... magnet, R ... rotor, 1 ... nut, 1a ... female screw, 2 ... shaft lead screw, 3 ... … Shaft, 3a …… Non-cylindrical front part of shaft, 3b …… Cylindrical rear part of shaft, 4 …… Mounting plate, 5 …… Stator yoke, 6 …… Rotor color, 7, 8 …… Bearing, 10 …… Fixed plate, 11 …… Coil, 12 …… Gap, 13 ……
Pole, 13a …… Half-piece, 14,15 …… Spacer, 15a ……
Spacer hole.

Claims (1)

[Scope of utility model registration request] 1. A lead screw provided on the outer periphery of a cylindrical portion of a shaft slidable in a hole provided in a rotor and a nut provided on a mounting plate of a stator yoke are screwed together in accordance with the rotation of the rotor. In a linear motor in which the shaft can be displaced in the axial direction, a spacer is interposed between the end of the rotor collar and the bearing, and half halves are provided on the upper and lower flat surfaces of the non-cylindrical portion of the shaft, respectively. A linear motor, characterized in that a half pole piece formed integrally with a spacer is provided so that it can be inserted into a gap formed by a shaft non-cylindrical portion and a bearing.