JPH0510532Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a thrust bearing structure for small motors, particularly pulse motors.

(Prior Art) Conventionally, as a technology in this field, a configuration example shown in FIG. 3 is known. This figure is a schematic side view showing an example of a configuration in which a magnetic head is run by a lead screw 3 provided on the shaft 2 of the pulse motor 1 and a pin connection (not shown). The section is shown cut away. In the figure, 4 is a rotor, and 5 is a ball such as a steel ball, which is provided at the lower end of the shaft 2 of the rotor 4. Reference numeral 6 denotes an elastic support plate made of an elastic member, the outer edge of which is fixed to the motor frame 7, and a contact portion 6a formed by cutting and raising the center portion facing the through hole 7a of the frame 7. The ball 5 contacts the upper surface and rotates. Note that 8 is a mounting body for the pulse motor 1, and the lead screw 3 is also supported by this.

Since the bearing of the pulse motor 1 is constructed as described above, when the thrust F in the direction of the arrow acts on the lead screw 3, the shaft 2 is also pushed down in the same direction, and the elastic support plate 6 is pushed down through the balls. Contact part 6
A was deflected, acting in balance with thrust F to continue rotating.

(Problems to be Solved by the Invention) However, in the thrust bearing structure with the above configuration, when a large thrust is applied to the shaft 2 during operation or assembly of the motor, the contact portion 6a is a cantilever beam, so
There are problems in that it easily wears out and product functionality is lost, and it also requires a lot of man-hours to disassemble and replace with a new elastic support plate.

This invention provides an apparatus that solves the problems of the prior art, such as plastic deformation, so-called sagging, of the abutting portion of the elastic support plate due to large thrusts.

(Means for Solving the Problems) In order to solve the above-mentioned problems, this invention provides a thrust bearing structure for a small motor that receives a thrust load by bringing the shaft end into contact with an elastic member via a ball. As an elastic member, a bearing spring is provided which has a positioning hole in the bottom piece and whose tip part is bent to form a contact part with the ball, and the positioning hole of this bearing spring is fitted and serves as a stopper for the contact part. A support plate is fixed to the bottom surface of the stator yoke, and has a protrusion in the center and a stepped portion shaped to prevent rotation of a fitted bearing spring.

(Function) According to the present invention, since the thrust bearing is configured as described above, when the bearing spring is inserted into the stepped portion of the support plate so that its positioning hole fits into the protrusion, the rotation inhibiting shape of the stepped portion This prevents the bearing spring from rotating within the stepped portion of the support plate around the protrusion, and the ball comes into contact with the correct position of the contact portion of the bearing spring. In addition, even if a large thrust is applied to the abutting part, the lower surface of the abutting part will hit the protrusion of the support plate and the abutting part will not bend any further, thus preventing the bearing spring from becoming sagging. Therefore, the above-mentioned problems can be eliminated.

(Example) Fig. 1 is a side sectional view of a main part showing an embodiment of the present invention, with the thrust bearing of the pulse motor cut away, and Fig. 2 is an exploded perspective view of the bearing. . In FIGS. 1 and 2, 11 is a stator yoke, 12 is a rotor, 13 is a shaft, 14 is a ball, 15 is a bearing spring, 15a is its bottom, 1
5b is the contact part with the ball 14, 15c is the bottom side 15
This is a positioning hole provided in a. Reference numeral 16 denotes a support plate which is provided with a hexagonal stepped portion 16a having one side approximately equal in length to the width of the bearing spring 15, and a protrusion 16b is provided at the center of the hexagonal stepped portion 16a, into which a positioning hole 15c is fitted. and the bearing spring 15 is attached to the support plate 16.
When inserted into the stepped portion 16a of the support plate 16, the bearing spring 15 is accurately maintained at a constant position within the stepped portion 16a of the support plate 16.

Note that the shape of the stepped portion 16a of the support plate 16 may be square, as long as it prevents the bearing spring 15 from rotating.

As described above, since the bearing part of the pulse motor is configured, even if a light thrust load is applied to the shaft 13 of the pulse motor during operation or assembly, the bearing spring 15 will elastically deform to cope with it. Even if a heavier thrust load is applied, the contact portion 15b contacts the protrusion 16b of the support plate 16 and stops, so the bearing spring 15 is further pushed and bent, exceeding its elastic limit and causing plastic deformation, a so-called sagging phenomenon. can be prevented.

(Effects of the invention) As explained in detail above, according to the invention, the support plate fixed to the stator yoke is provided with a hexagonal step having a protrusion at the center thereof, and the protrusion has a positioning hole therein. When the bearing spring is fitted into the stepped portion in the same manner as the hexagonal stepped portion, the bearing spring is easily and securely installed in the desired position, and at the same time, both ends in the width direction hit the corners of the hexagonal stepped portion and rotate. Provides a stopping effect. In addition, the bearing spring that has achieved this effect exhibits a thrust bearing effect by performing moderate elastic deformation in response to a small thrust load received from the shaft via the ball, and provides a thrust bearing effect in response to a relatively large thrust load. However, since the contact portion contacts the protrusion of the support plate and acts as a stopper, it will not be bent any further, so that the so-called sagging phenomenon, which causes plastic deformation, is prevented from occurring.

Therefore, even if a large frustration load is applied during operation or assembly, the bearing spring will not weaken, so unlike conventional products, the product function will not be lost, and handling during assembly can be done easily and safely. As a result, it is expected that a bearing structure of high quality and high reliability will be obtained, and furthermore, it can be applied to other small motors.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of the main part showing an embodiment of the present invention;
FIG. 2 is an exploded perspective view of the bearing shown in FIG. 1, and FIG. 3 is a partially cutaway side view showing an example of a conventional configuration. 11...Stator yoke, 12...Rotor,
13... Shaft, 14... Ball, 15... Bearing spring, 15a... Bottom piece, 15b... Contact portion, 15c
...Positioning hole, 16...Support plate, 16a...Step portion, 16b...Protrusion.

Claims (1)

[Scope of utility model registration request] In a thrust bearing structure for a small motor that receives a thrust load by bringing the shaft end into contact with an elastic member via a ball, the elastic member has a positioning hole in the bottom piece, and the tip is bent to make contact with the ball. A bearing spring is provided in which a positioning hole of the bearing spring is fitted, the projection has a projection in the center that serves as a stopper of the abutting part, and the step has a shape that suppresses rotation of the fitted bearing spring. A thrust bearing structure for a small motor, characterized by a support plate having a portion fixed to the bottom surface of a stator yoke.