JP2767894B2 - Linear motion motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motion motor used for driving intake and exhaust valves for automobiles.

2. Description of the Related Art In recent years, with the development of car electronics, linear motion motors have been used for controlling intake and exhaust valves of automobiles.

Hereinafter, the above-described conventional linear motion motor will be described with reference to the drawings.

In FIG. 2, reference numeral 1 denotes a rotor, which is composed of an insert 2 having a female screw portion 2a on a part of the inner periphery and a magnet 3. Reference numeral 4 denotes a main shaft provided with a feed screw portion 4a engaged with the female screw portion 2a and a notch 4b for preventing rotation in the circumferential direction. Reference numeral 5 denotes a stator which is located opposite to the magnet 3, and comprises a frame 6, a coil 8 wound around a bobbin 7, a yoke 9, and a mold portion 5a for holding these.

The inner diameter of the load-side end of the insert 2 is a load-side ball bearing
The insert 2 is rotatably supported by an outer ring, and the outer diameter of the opposite end of the insert 2 on the non-load side is rotatably supported by the inner ring of the non-load side ball bearing 11.

The load-side ball bearing 10 is supported by a load-side metal 13 fixed to a bracket 12, and the outer ring of the non-load-side ball bearing 11 is supported by a molded portion 5a.

The bracket 12 is fixed to the stator 5 by a mold support 5b.

Regarding the linear motion motor configured as described above,
The operation will be described.

First, when the coil 8 is excited by an external power supply, the rotor 1, that is, the female screw portion 2a rotates. Since the feed screw portion 4a of the main shaft 4 is engaged with the female screw portion 2a, the rotary motion of the rotor 1 is converted into a linear motion of the main shaft 4.

However, in the above configuration, considering the axial dimension of the motor, the outer ring of the anti-load side ball bearing 11 is supported by the mold portion 5a,
Since the outer diameter portion smaller than the outer diameter of the magnet 3 at the non-load side end of the insert 2 is supported by the inner ring of the non-load side ball bearing 11, the total length of the rotor is equal to the length of the non-load side ball bearing 11. It was almost as long as. Further, the main shaft 4 is supported by the load side metal 13 and the female screw portion 2a, and a backlash of 0.1 mm or more is provided between the female screw portion 2a and the feed screw portion 4a. And the accuracy of valve control deteriorates.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a linear motion type in which the performance of a conventional motor is sufficiently ensured, the axial dimension of the motor is shortened without changing the axial length of the magnet, and the tip of the spindle is free from deflection. A motor is provided.

Means for Solving the Problems In order to achieve this object, the linear motion motor of the present invention supports the inner diameter portions of both ends of the rotor with the outer ring of a ball bearing, and supports the non-load side bearing, and An anti-load side metal supporting the anti-load side feed screw portion with its inner diameter is fixed to the frame.

By arranging the two bearings within the axial length of the rotor according to the above configuration, the axial dimension of the motor can be reduced, and the load-side feed screw portion of the main shaft is connected to the non-load side. Since the main shaft is supported at two points between the load-side metal and the main shaft by being inserted and supported in the inner diameter of the metal, it is possible to provide a linear motion motor with less deflection at the front end of the main shaft and to perform highly accurate valve control.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a linear motion motor according to an embodiment of the present invention. The same functional components as those in the conventional example are denoted by the same reference numerals.

In FIG. 1, reference numeral 1 denotes a rotor, which comprises an insert 2 having a female screw portion 2a on a part of the inner periphery and a magnet 3. Reference numeral 4 denotes a main shaft having a male screw portion 4a engaged with the female screw portion 2a and a notch 4b for preventing rotation in the circumferential direction. Reference numeral 5 denotes a stator positioned opposite to the magnet 3 and includes a frame 6, a coil 8 wound around a bobbin 7, and a yoke 9.

Ball bearings having the same inner diameter at both ends of the insert 2
The magnet 3 is rotatably supported by outer rings 10 and 11, and the magnet 3 is positioned so as to cover the outer circumference of the outer rings of the two ball bearings 10 and 11.

The load-side ball bearing 10 is supported by a load-side metal 13 fixed to a bracket 12, and the non-load-side ball bearing 11 is supported by an anti-load-side metal 14 fixed to the frame 6. The opposite end of the main shaft 4 on the non-load side is slidably supported by the inner diameter of the non-load side metal.

 The bracket 12 is fixedly bonded to the frame 6.

Regarding the linear motion motor configured as described above,
The operation will be described.

When the coil 8 is excited by an external power supply, the rotor 1, that is, the female screw portion 2a rotates. Feed screw 4a of main shaft 4
Is engaged with the female screw portion 2a, so that the rotary motion of the rotor 1 is converted into the linear motion of the main shaft 4.

At this time, since the main shaft 4 is supported at two places, that is, the load side metal 13 and the non-load side metal 14, the deflection of the tip of the main shaft 4 is reduced as compared with the conventional example.

In the present embodiment, ball bearings having the same dimensions are used, but it goes without saying that this selection can be made freely.

Effect of the Invention As described above, the present invention has inner diameter portions at both ends supported by the outer ring of a ball bearing having the same dimensions, and a magnet covering the outer peripheral portion of the outer ring of the ball bearing and a female screw provided on a part of the inner periphery. A rotor, a main shaft provided with a feed screw portion engaged with the female screw portion and a notch portion for preventing rotation in the circumferential direction, a load-side metal fixed to the bracket, supporting an inner ring of the load-side ball bearing; , Which is fixed to the frame, supports the inner ring of the load-side ball bearing, and is slidably supported at the non-load-side end of the main shaft, so that it has a length substantially equal to the axial length of the magnet. In addition, a rotor that wraps the load-side and anti-load-side ball bearings can be configured, so that the overall length of the motor can be made extremely thin, and a motor with less run-out of the spindle tip can be provided. Bubble control can be performed, The practical effects are significant.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a linear motion motor according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a conventional linear motion motor. 1 ... rotor, 2a ... female screw part, 3 ... magnet, 4a
... Spindle, 4a ... Feed screw, 4b ... Notch, 5 ...
Stator, 6… Frame, 10… Load ball bearing, 11…
Non-load side ball bearings, 12: Bracket, 13: Load side metal, 14: Non-load side metal.

Claims (1)

(57) [Claims] 1. A rotor having inner ends at both ends supported by an outer ring of a ball bearing, a ball bearing disposed in a concave portion, a magnet covering an outer peripheral portion, and a rotor provided with a female screw portion on a part of an inner periphery; A main shaft having a male screw engaged with the female screw portion and a notch for preventing rotation in the circumferential direction, and a notch for preventing rotation of the main shaft are engaged to support an inner ring of the load-side ball bearing. From the load-side metal fixed to the bracket and the non-load-side metal fixed to the frame and supporting the inner ring of the anti-load side ball bearing with its outer diameter and slidably supporting the male screw part of the main shaft at the inner diameter. Linear motion motor.