JPS61206975A - Guiding mechanism - Google Patents

Abstract

PURPOSE:To obtain a cheap and highly accurate guiding mechanism without injuring slidability between a bearing and a guide rod by holding a cylindrical bearing by supports provided to the front and back of moving direction of a positioning device, inserting a guide rod in the cylindrical bearing and forming a recessed part in the cylindrical bearing. CONSTITUTION:Nearly U-shaped supports 8a, 8b are provided on both ends of the moving direction of a moving stand 8. Outer peripheral parts of both ends of a cylindrical bearing 9 are joined to holes 10a, 10b of the supports 8a, 8b provided on the moving stand 8 by bonding agent etc. to form a solid structure. The cylindrical bearing is constituted of a sintered oiled bearing, and contact faces 9a, 9b with a guide rod 6 having both ends made to small diameter to correspond to the guide rod 6 and holes 10a, 10b of supports 8a, 8b, and a non-contact concavity 9c is formed between the two contact faces 9a, 9b. Thus, precise guiding restriction between the guide rod 6 and cylindrical bearing, that is, between the guide rod 6 and moving stand 8 can be realized surely without influenced by rigidity and accuracy of working around holes 10a, 10b of the moving stand.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a guide mechanism in a positioning device such as a magnetic head moving device.

[Conventional technology]

Currently, in flexible disk (magnetic information recording media, hereinafter referred to as floppy) storage devices that are widely used, in order to ensure compatibility between floppy disks and between floppy storage devices, there are The magnetic head is required to have accurate and high positioning accuracy with respect to the rotation center of the floppy disk.

FIGS. 5 and 6 are a plan view and a cross-sectional view taken along the line 1--2 of a conventional magnetic head moving device using a guide mechanism. In each figure, the symbol (■) indicates a magnetic head that moves in the radial direction along the surface of the floppy disk 2 to record or reproduce information.The magnetic head 1 is held on a movable base 3 that constitutes a positioning device. The movable base 3 is mainly made of engineering plastic material by precision injection molding, etc., and has two holes with excellent sliding properties in holes 4a and 4b of the holders 3a and 3b provided at both ends in the moving direction. Bearings 5a and 5b are fitted. for example,
Self-lubricating Teflon.

Bearing 5a such as PPS or sintered oil-impregnated bearing.

The bearings 5a and 5b are attached to the movable base 3 by press-fitting the bearings 5b into the holes 4a and 4b, respectively, or joining them with adhesive or the like.
It is held in an integrated structure.

Guide rods 6 are inserted into these bearings 5a and 5b, and the movable base 3 is guided along the guide rods 6 to enable guidance.
It forms a guide mechanism. By rotating the drive motor 7 by a certain angular displacement, the magnetic head 1 bonded to one surface of the movable base 3 can be moved and positioned at a predetermined position. As for the structure of the method for moving and positioning, a detailed explanation will be omitted since it can be realized by a very ordinary mechanism, but as shown in the figure, a mechanism using a threaded connection between a shirt 7a and a bearing 3C is used. Note that 5a and 5b are supports that support the guide rod 6.

In this conventional magnetic head moving device, the moving base 3
The accuracy of the holes 4a and 4b at both ends of the hole, that is, the roundness of the inner diameter of the 1-round hole, and the coaxiality of both the holes 4a and 4b are required to have strict dimensions. From the viewpoint of mass production, it is expensive to construct the entire movable base 3 with a metal object, so
An engineering plastic material with relatively little heat shrinkage is selected, and an inexpensive movable base 3 made by precision injection molding is used.

[Problem that the invention seeks to solve]

By the way, in this type of conventional guide mechanism, it is important to improve positioning accuracy and reduce contact resistance between the guide rod and the bearing.
This is achieved by holding the two bearings 5a, 5b with holders 3a, 3b provided at both ends in the direction of movement, and arranging them at a precise distance. However, as mentioned above, due to the precision injection molding process of the movable base 3, the holes 4a and 4 of the holders 3a and 3b are
machining b into a perfect circle, and forming a hole 4a at a distance,
It is difficult to improve the center of 4b, that is, the coaxiality, to the level of precision machining by mechanical cutting. After the forming process, holes 4a at both ends are formed by machine cutting.

By modifying 4b, the hole inner diameter and roundness can be improved.

Improved coaxiality and accuracy have been achieved. As a result, the movable base 1 has become an expensive component that requires expensive processing techniques.

The present invention has been made to solve these problems, and an object of the present invention is to provide an inexpensive and highly accurate guide mechanism without impairing the slidability between the bearing and the guide rod.

[Means for solving problems]

The guide mechanism according to the present invention holds a cylindrical bearing extending in the front-rear direction with at least two holders provided before and after the moving direction of the positioning device, and a guide rod is inserted into the cylindrical bearing. A concave portion is formed in the top.

[Effect]

In the present invention, the cylindrical bearing held by the holder slides along the guide rod. At this time, since a recess is formed in the cylindrical bearing, sliding performance is not impaired.

〔Example〕

Hereinafter, the present invention will be explained by showing examples. Note that the same reference numerals are used for the same or equivalent parts as in the conventional example, and the explanation thereof will be omitted.

FIG. 1 is a plan view showing a magnetic head moving device to which an embodiment of the guide mechanism according to the present invention is applied, FIG. 2 is a perspective view of the main parts thereof, and FIG. 3 is a sectional view taken along the line IV-IV in FIG. 1. It is. In each figure, reference numeral 8 denotes a movable base in this embodiment, and this movable base 8 is provided with substantially U-shaped holders 8a and 8b, which are different from the conventional example, at both ends of the movable base in the moving direction.

Reference numeral 9 denotes a cylindrical bearing provided according to the present invention, and the outer periphery of both ends of this cylindrical bearing 9 is attached to a holder F3a provided on the movable base 8.
.

It is joined to the holes 10a and 10b of 8b with an adhesive or the like to form an integrated structure. This cylindrical bearing 9 is composed of a sintered oil-impregnated bearing, and both ends thereof are connected to a guide rod 6 and a holder 8.
Corresponding to the holes 10a and 10b in holes a and 8b, contact surfaces 9a and 9b with the guide rod 6 are formed with small diameters, and a re-contact surface 9 is formed.
A non-contact recess 9c is formed between a and 9b.

Since the bearing is made of metal and has a cylindrical shape, the inner diameter of the shaft hole is, for example, φ4±0.004 m.

It is easily guaranteed that the roundness is, for example, ±0.002 m, and the coaxiality is, for example, ±0.005/40 m.

Therefore, precise guidance and restraint between the guide rod 6 and the cylindrical bearing 9, that is, the guide rod 6 and the movable base 8, is ensured without being affected by the rigidity and processing accuracy around the holes 10a and 10b of the movable base 8. can be realized. Further, since the contact surfaces 9a and 9b with the guide rod 6 are at both ends of the cylindrical bearing 9, it is possible to reduce the viscous resistance force proportional to the contact area, which is a characteristic of sintered oil-impregnated bearings. Furthermore, since the holes 10a and 10b can be changed from the conventional round holes to O-shaped holes, the mold of the movable base 8 can be constructed from a simple structure of an upper mold and a lower mold. Therefore, it is possible to reduce the cost of expensive molds and improve the life of the molds, and as a result, it is possible to provide a highly accurate and inexpensive magnetic head moving device.

FIG. 4 is a sectional view showing another embodiment of the invention. In this embodiment, the contact surfaces with the guide rod 6 are formed by contact surfaces 9a and 9b at both ends of the cylindrical bearing 9, as well as a contact surface 9d at the intermediate portion. For a magnetic head moving device that can tolerate a larger viscous drag force than in the embodiment described above, the same effects as in the embodiment described above can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, a cylindrical bearing extending in the front-rear direction is held by at least two holders provided before and after the moving direction of the positioning device, and a guide rod is inserted through the cylindrical bearing. By forming the recess in the cylindrical bearing, an inexpensive and highly accurate guide mechanism can be obtained without impairing the slidability between the bearing and the guide rod.

[Brief explanation of drawings]

FIG. 1 is a plan view of a magnetic head moving device to which an embodiment of the guide mechanism according to the present invention is applied, FIG. 2 is a perspective view of the main parts thereof, and FIG. 3 is a sectional view taken along the line IV-IV in FIG. 1. Fourth
5 is a sectional view showing another embodiment of the present invention, FIG. 5 is a plan view of a magnetic head moving device using a conventional guide mechanism, and FIG. 6 is a sectional view taken along line u--n in FIG. 5. 1... Magnetic head, 2... Magnetic information recording medium, 6.
... Guide rod, 8... Moving base, 8a. 8b...Holding body, 9...Cylinder bearing, 9C...Concave portion. Note that the same reference numerals are used for the middle part of the figure or corresponding parts.

Claims (2)

[Claims] (1) A cylindrical bearing extending in the front-rear direction is held by at least two holders provided at the front and rear in the moving direction of the positioning device, a guide rod is inserted through the cylindrical bearing, and a recess is formed in the cylindrical bearing. A guide mechanism characterized by: (2) The positioning device comprises a magnetic head that moves along the surface of a magnetic information recording medium to record or reproduce information, and a movable base that holds this magnetic head. The guide mechanism described in scope 1.