JPS62222464A - Guide and supporting mechanism for linear actuator - Google Patents

Abstract

PURPOSE:To heighten the rotating accuracy of a bearing, and to improve the rigidity of the bearing, by bringing an inner ring and an outer ring into contact with a ball at two places, a contact part with the travelling path of the bearing, and a part facing with the above part, and stabilizing relatively a position between the inner ring and the outer ring. CONSTITUTION:In a bearing 11 mounted at a carriage, an outer ring 13 and a travelling path 14 are set obliquely against an inner ring 12. An inclination is arranged at a position where a contact part A of the outer ring 13 with the travelling path 14 passes through the center position of the inner ring 12, and the position except an intersection of an inner ring orbit plane B that is a straight line extending in the radial direction of the inner ring 12, and the travelling path 14. By constituting a device in such way, a moment that inclines the outer ring 13 from the travelling path 14 against the inner ring 12 in the bearing 11, is generated against the reaction F of a pre-load, and the inner ring 12 and the outer ring 13 are dislocated in a shaft direction, and the ball 15 is sandwiched with the outer ring 13 and the inner ring 12 at two places, at least, the contact part A that is brought into contact with the travelling path 14 of the bearing 11, and the part facing with the part A, therefore, the inner ring 12 and the outer ring 13 are brought into contact with the ball 15 at those places, and the positions of the inner and the outer rings 12 and 13 can be stabilized.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a guide support mechanism that guides and moves a carriage in a linear actuator that drives the carriage by a linear motor, and particularly relates to a guide support mechanism that guides and moves the carriage. The present invention relates to something suitable for positioning a magnetic head of an apparatus with high precision.

[Prior art]

Generally, in magnetic disk drives used in large computers, etc., there is a carriage that holds the magnetic head.

A linear actuator has a linear motor that drives the carriage, and a guide support mechanism that guides and moves the carriage. When the carriage is driven by the linear motor, the carriage moves while being guided by the guide support mechanism. The magnetic head is positioned at a desired position on the disk so that the magnetic head reads data from or writes data to the disk.

Therefore, in order to accurately position the magnetic head with respect to the disk, it is necessary to increase the positioning accuracy of the linear actuator, and therefore, it is required that the guide support mechanism that guides the carriage be highly accurate.

The conventional technology as a guide support mechanism is disclosed in Japanese Patent Application Laid-Open No. 54-148.
There is a known technique disclosed in Japanese Patent No. 509.

As shown in FIG. 4, in this known technology, a plurality of miniature bearings 1 mounted on a carriage 6 and a running path 4 on which an outer ring 3 of the bearings 1 rolls come into contact with each other with a constant force. A preload means (not shown) made of an elastic member or the like is provided so that the bearing 1 runs on
The gaps between the inner ring 2, the balls 5, and the outer ring 3 on the side that should be in contact with are eliminated, thereby reducing the rotational runout of the bearing and improving the positioning accuracy of the linear actuator.

[Problem that the invention seeks to solve]

By the way, preload on a bearing is generally applied in the thrust direction. By applying preload in the thrust direction, the inner ring, balls, and outer ring of the bearing come into uniform contact with each other, increasing the accuracy of preventing rotational runout of the bearing. As a result, the positions of the inner and outer rings of the bearing are stabilized, and the rigidity is increased to prevent vibration.

However, in the above-mentioned known technology, the bearing 1 is
Since a preload is applied in the radial direction of the bearing 1, the outer @3 and inner lI! parts of the bearing 1 that are in contact with the running path 4! ! 2 is narrow, while the distance between the outer ring 3 and the inner ring 2, which are the parts on the opposite side, is widened. Therefore, when vibration occurs in the carriage 6 due to high-speed driving, the inner ring 2 and the outer ring 3 of the bearing 1 Since the relative position changes and there is a risk that the rotational accuracy may decrease, the positioning accuracy of the carriage 6, that is, the positioning accuracy of the linear actuator will decrease.

In view of the above circumstances, an object of the present invention is to provide a guide support mechanism for a linear actuator that can relatively stabilize the positions of the inner ring and outer ring of a bearing, thereby increasing the positioning accuracy of the linear actuator.

[Means for solving problems]

In the present invention, the outer ring axis and running path of at least one bearing are arranged at an angle with respect to the inner ring, and the contact portion between the outer ring and the running path passes through the center position of the inner shaft of the bearing, and It is arranged at a position excluding the intersection between the inner race track line, which is a straight line position extending in the radial direction of the inner shaft, and the running path.

[Effect]

In order to improve the rotational accuracy of a bearing, it is desirable to have the inner and outer rings of the bearing in uniform contact with all the balls. Therefore, in bearings used for spindles, etc., a thrust preload is applied to shift the inner and outer rings in the axial direction. , the ball is sandwiched between the inner and outer rings.

However, in the guide support mechanism of a linear actuator, it is difficult to apply the above-mentioned thrust preload due to its structure, but a method similar to this is to tilt the inner ring and outer ring of the bearing so that they are offset from each other in the axial direction. is possible.

In the present invention, as described above, the outer ring and the running path are inclined with respect to the inner ring of the bearing, and the contact point between the outer shaft and the running path is located at a position that avoids the intersection between the inner raceway surface and the running path. Therefore, the inner ring and outer ring of the bearing are misaligned in the axial direction,
The inner and outer rings and the balls come into contact at two places: the part of the bearing that is in contact with the running path, and the part that is not.

As a result, the positions of the inner and outer shafts of the bearing are stabilized on the same axis, which eliminates vibrations when the carriage moves, increasing the precision of positioning the carriage.As a result, the magnetic head held by the carriage can be Accurate positioning is possible.

〔Example〕

The details of the present invention will be explained below with reference to FIGS. 1 to 3. FIG. 1 is an explanatory diagram showing the basic principle of the present invention, FIG. 2 is a schematic perspective view showing a magnetic disk device to which the present invention is applied, and FIG. 3 is an enlarged view of the main parts of the guide support mechanism.

Before explaining the present invention in detail, the basic principle of the present invention will be described. That is, the basic principle of this guide support mechanism is that, as shown in FIG. 1, a bearing 11 is attached to a carriage 16, and an outer ring 13 and a running path 14 are inclined with respect to an inner shaft 12. The inclination is such that the contact area A between the outer ring 13 and the running path 14 is
The inner ring raceway surface B, which is a straight line passing through the center of the inner shaft 12 and extending in the radial direction of the inner shaft 12, and the running path 14 are arranged at positions other than the intersection C between the inner raceway surface B and the running path 14.

In this way, the running path 1 is
A moment that tilts the outer ring 13 from 4 is generated by the reaction force F of the preload, and the inner ring 12 and the outer ring 13 are shifted in the axial direction, and the contact portion A is in contact with the running path 14 of the bearing 11. Since the balls 15 are sandwiched between the outer ring 13 and the inner ring 12 at at least two places, namely, and the corresponding part A', the ball 15 is held in place by these parts.

The outer ring 12.13 and the ball 15 are in contact.

As a result, the positions of the inner shaft 2 and outer ring 3 of the bearing 1 can be improved compared to the conventional example in which the inner and outer rings 2, 3 and the balls 5 are in contact only at the contact portion of the bearing 1 with the running path 4. It can be kept stable.

Next, an embodiment of a linear actuator based on the basic principle of the present invention will be described with reference to FIGS. 2 and 3.

In those figures, the magnetic head 20 is shown on the carriage 26.
The carriage 26 is configured to be driven by a voice coil motor comprising a coil section 27 and a magnetic circuit section 28 mounted at the rear thereof.

Further, a guide support mechanism is installed that guides and moves the carriage 26 when it is driven. The guide support mechanism includes a bearing 21 attached to a carriage 26, a running path 24 on which an outer ring 23 of the bearing 21 rolls, and a preload means 29 for pressing the running path 24 and the outer ring 23 of the bearing. There is.

The bearings 21 have inner parts i11!22 attached to shafts 30 provided on both sides of the carriage 26, and for example, a total of eight bearings, four on each side, are used, including a preload bearing 21a and a positioning bearing 21b. It's getting better.

The traveling path 24 has carriages 26 on both sides of the base 31.
The carriage 26 is composed of a cylindrical rail supported along the direction of movement of the carriage 26, and the carriage 26 is guided by the rolling of the outer ring 23 of the bearing 21.

The preloading means 29 is composed of a coil spring compressed between the base 31 and four parts provided on the running path 24, and the elastic force of the coil spring causes the running path 24 to be compressed into the outer ring 23 of each preloading bearing 21a. I try to push myself.

Then, the outer ring shaft 23' is connected to the inner ring shaft 22' of the bearing 21b.
And the running road surface 24 is arranged at an angle. That is, the inclination is such that the contact area A between the outer wheel shaft 23' and the running road surface 24 is
It is arranged at a position excluding the intersection C between the inner ring track line B and the running road surface 24, and in the illustrated example, the inner ring shaft 22' is arranged so as to form an angle of 0 of 15 degrees with the outer ring shaft 23' and the running road 24. has been done.

The inner shaft orbit line B is a straight line passing through the center of the inner shaft 22 and extending in the radial direction of the inner ring 22.

When the guide support mechanism configured as described above is used.

At the contact point A between the outer ring 23 of the bearing 21 and the running path 24, as explained in the basic principle of the present invention, a moment is generated that tilts the outer ring 23 with respect to the inner shaft 21 due to the reaction force F of the preload means 29. However, as a result of the inner ring 21 and the outer ring being shifted in the axial direction, the contact portion A of the bearing 21.

In at least two places, this and the corresponding part, inside.

Since the outer rings 22, 23 and the balls 25 are in contact with each other, the positions of the inner ring 22 and the outer ring 23 can be relatively stabilized.

Therefore, the rigidity of the bearing 21 is increased, the vibration characteristics are improved, and the rotational accuracy of the bearing 21 can be increased. Therefore, the vibration that occurs when the linear actuator is driven at high speed can be reduced, and the positioning accuracy of the linear actuator can be improved.

Further, in the illustrated embodiment, the outer ring shaft 23' is different from the inner ring shaft 22'.
In order to tilt the running road surface 24, this can be done by only slightly changing the position of the inner race shaft 23', so it can be carried out extremely easily.

Furthermore, although the illustrated example shows an example in which the position of the inner race shaft 23' is changed, the present invention is not limited to this, and for example, the diameter of the running path may be changed to change the position of the running path, etc. A similar effect can be obtained.

〔Effect of the invention〕

As described above, the present invention brings the inner and outer rings into contact with each other at at least two places, the contact part with the running path and the corresponding part of the bearing, and relatively positions the inner ring and the outer ring. Since the structure is designed to be stable, the rotation accuracy of the bearing can be reliably increased, and as a result, the rigidity and vibration of the bearing can be improved.

Therefore, it is possible to reduce vibrations that occur when the linear actuator is driven at high speed, and it is possible to achieve highly accurate positioning of the linear actuator.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are an explanatory cross-sectional view and an explanatory side view showing the basic principle of the present invention, FIG. 2 is an overall perspective view of a linear actuator showing an embodiment of the present invention, and FIG. 4(a) and 4(b) are an explanatory cross-sectional view and an explanatory side view showing a conventional example of a guide support mechanism for a linear actuator. II, 21...Bearing, 12.22...Inner ring, 12
', 22'...Inner ring shaft, 13.23...Outer ring, 13
', 23' Outer wheel shaft, 14.24... Traveling path, 1.6
．． 26... Carriage, 20... Magnetic head, A.
...Contact part between outer ring and running track, B...Inner shaft track line, C
...Intersection between the inner ring track line and the running road. Representative Patent Attorney Tadashi Akimoto Figure 1 (a) (b) Figure 2 Kaku 3 Figure 1b

Claims (1)

[Claims] 1. At least one bearing, comprising a plurality of bearings attached to a carriage whose inner ring holds a magnetic head, a running path on which an outer ring of the bearing rolls, and a preload means for pressing the outer ring and the running path. The outer ring axis is arranged at an angle with respect to the inner ring axis, and the contact portion between the outer ring and the running path is such that the inner ring raceway line passing through the center of the inner ring and extending in the radial direction of the inner ring intersects with the running path. A guide support mechanism for a linear actuator, characterized in that the mechanism is arranged at a position other than a position where the linear actuator is moved.