JPH0348375B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

This invention is a device for linearly transporting a traveling platform over a certain range, in which the traveling platform is linearly moved along a guide rail via a steel belt that is tightly wound once around a capstan attached to a drive motor shaft. This invention relates to a mechanism that guides and drives the vehicle, that is, a guide drive mechanism for a traveling platform.

[Prior art and its problems]

Generally, in a mechanism for linearly guiding a carriage along a guide rail, play of the carriage in directions other than the guiding direction, that is, the feeding direction, is usually extremely strictly suppressed. Additionally, it is required to reduce the load as much as possible during sending. Particularly when used in a magnetic disk device, the play in directions other than the feeding direction required for the guide mechanism of the traveling platform equipped with the magnetic head, the load required for feeding, or the mass of the traveling platform including the magnetic head are extremely severe. subject to restrictions. A conventional example of a guide mechanism used in a magnetic disk device will be described with reference to FIG. 3A shows a plan view of a conventional example, FIG. 3B shows a front view thereof, and FIG. 3C shows a side view thereof. 1 is a step motor, and 2 is a capstan, which is attached to the shaft of the step motor 1. A steel belt 3 is wrapped once around the capstan 2 and fastened at one point with a pin or screw to prevent it from slipping. On the other hand, the carriage 4 on which a magnetic head (not shown) is mounted is guided along the axial direction of two parallel guide rails 10A and 10B having circular cross sections, as will be described later. The feed of the traveling base 4 is carried out by the steel belt attachment parts 4A, 4 of the traveling base 4.
Both ends of the steel belt 3 are fixed to B, and the step motor 1 is rotated. The shaft 14 is press-fitted and fixed at positions A1, A2, and B corresponding to the vertices of a triangle arranged on one side of the traveling base 4,
An inner ring of a radial ball bearing 6 (not shown) is press-fitted into the other end of this shaft 14, and this radial ball bearing 6
Press-fit the V-grooved wheel 7 into the outer ring. Said position A
The direction in which 1 and A2 are connected is the steel belt 3.
Both ends of the step motor 1 are set parallel to the direction of movement by the rotation of the step motor 1. Said V-groove wheel 7
The guide rails 10A, 10B are in contact with the groove surfaces of the guide rails 10A, 10B.
is placed. At this time, the guide rail 10
One guide rail 10A of A, 10B is fixedly held at both ends, but a certain preload is applied to the guide rail 10A by a spring 8 shown in the schematic diagram on the other guide rail 10B, and the guide rail 10A is given at right angles to the axial direction. The load has the function of removing play in the radial direction between the inner and outer rings of the radial ball bearing 6 press-fitted into the center of the V-grooved wheel 7. Further, another radial ball bearing 13 is provided on the traveling platform 4 using a mounting bracket 11 and a shaft 12. That is, the mounting bracket 11 is
It is bent at a substantially right angle, and is fixed to the surface of the traveling table 4 by screwing on one side, and a shaft 12 is fixed to the end of the other side perpendicular to this plane,
The radial ball bearing 13 is press-fitted into the end of this shaft 12. Furthermore, the mounting bracket 11 has spring properties in the radial direction of the radial ball bearing 13. The radial ball bearing 13 is arranged to support the guide rail 10A from below, and due to the spring action of the mounting bracket 11 mentioned above, the guide rail 10A
gives an upward force to. Therefore, a reaction force of the above-mentioned upward force acts on the radial ball bearing 13, and the play in the radial direction of the radial ball bearing 13 is removed by this reaction force. Further, due to the upward force acting on the guide rail 10A from the radial ball bearing 13, the guide rails 10A, 1
0B applies a force with a vertical component to the V-grooved wheel 7 at its contact point. This force removes the play in the thrust direction between the inner and outer rings of the radial ball bearing 6. As described above, in the conventional guide structure for the traveling platform 4, the radial ball bearing 13 is installed in order to eliminate the play in the thrust direction between the inner and outer rings of the radial ball bearing 6, which is the rolling part. make use of,
It is necessary to apply a certain force with a component force in the thrust direction. This not only increases purchasing costs due to additional parts, but also increases man-hours for assembly and adjustment.Furthermore, the increased mass of the traveling platform has the disadvantage of impeding the basic function of magnetic disk drives, which is high-speed access. be.

[Purpose of the invention]

The purpose of the present invention is to eliminate the drawbacks of the conventional example as described above, to make the guide system of the traveling platform free from play through a simpler structure, and at the same time to reduce the weight of the traveling platform. .

[Key points of the invention]

The main points of this invention are three V-grooved wheels arranged at the vertices of a triangle in the same plane and two parallel guide rails having a circular cross section for supporting and guiding the running platform. The guide rail is brought into contact with the V-groove surface of the V-grooved wheel by applying a preload force, and the tension direction of the steel belt for feeding the running platform is inclined with respect to the feeding direction of the running platform. It is in. That is, by applying a component of tension in the axial direction of the V-grooved wheel by inclining the tension direction of the steel belt, the radial ball bearing fitted into the center of the V-grooved wheel is This removes the play between the inner and outer rings in the thrust direction. Incidentally, the play in the radial direction between the inner and outer rings is extremely small, but it is removed by the force applied in advance to the guide rail described above.

[Embodiments of the invention]

One embodiment of this invention will be described with reference to FIG. Figure 1a shows a plan view of this embodiment, and Figure 1b shows a plan view of this embodiment.
2 shows a front view, 3e shows a side view, and d shows a cross-sectional view of a main part. This embodiment differs from the above-mentioned conventional example in that the mounting bracket 11, shaft 12, and radial ball bearing 1 shown in FIG.
3 was removed, and the tension direction of the steel belt 3 for running the carriage was changed. That is, in the tension direction of the steel belt 3, from the capstan 2 attached to the shaft of the step motor 1 to the respective mounting portions 4A of the running base 4,
The direction toward 4B is made to be inclined with respect to the axial direction of guide shafts 10A and 10B, which will be described later. In other words,
This means changing the installation position of the capstan 2 and, by extension, the step motor 1. By adopting the above-described configuration, the play in the thrust direction between the inner and outer rings of the radial ball bearing 22 can be removed by the tension of the steel belt 3 as described below. be done. As shown in Figure 1b, the steel belt 3
The tension T is the steel belt attachment part 4 of the running platform 4.
Since the tension T acts on the guide rails 10A and 4B, it is considered by dividing it into the direction of the guide rails 10A and 10B and the direction perpendicular thereto, that is, the axial direction of the V-grooved wheel. The former is in equilibrium, and the latter is the resultant force P when the traveling platform 4
Acts on the central position of the steel belt mounting position. As shown in Fig. 1c, this resultant force P is
Let's break it down into three parallel forces that act on three points where the V-grooves of the V-grooved wheels 21 inserted at positions A1, A2, and B come into contact with the guide rails 10A and 10B, respectively. Hereinafter, the V-grooved wheels 21 inserted in positions A1, A2, and B, respectively, will be described as A1 wheel, A2 wheel, and B.
We will call it the wheel. Contact point of A1 wheel with guide rail 10A and A2 wheel guide rail 10A
The distance between the line connecting the point of contact with and the line of action of force P is
Similarly, the distance between the welding point of the B wheel with the guide rail 10B and the line of action of the P is Lb, and the forces acting on the A1 wheel and the A2 wheel are of the same magnitude.
Pa, B If the force acting on the wheel is Pb, then from the law of decomposition of parallel forces, Pa=P・Lb/2 (Lb−La) Pb=P・La/(Lb−La) Note that Pa, Pb The direction of the force is as shown in Figure 1c. In other words, the previous P is equivalently decomposed into two parts, Pa and Pb. Moreover, this has the following meaning. In other words, since the system of the traveling platform 4 is balanced by the external force acting on it, the external force in this case is P, which is equal in magnitude to Pa and Pb found above, and opposite in direction. External forces acting from the guide rail 10A on the contact points of the A1 and A2 wheels with the guide rail 10A, respectively, and B
This is an external force that is applied from the guide rail 10B to the point of contact between the wheel and the guide rail 10B. Therefore, the radial ball bearing 22 fitted into the center of each wheel receives a moment due to the action of the external force Pa or Pb, and this moment removes the play between the inner and outer rings of the radial ball bearing 22. Ru. In other words, the moment acts as a preload force to eliminate play in the radial ball bearing 22. By the way, if Lb=2La, from the above formula,
Pa=Lb=b. In other words, the magnitude of the force acting on each wheel, and therefore the magnitude of the moment, can be made equal, so
The life of the radial ball bearing 22 can be balanced. Next, as shown in Fig. 2, the line of action of the axial component P of each wheel of the tension T of the steel belt is
Consider the case where the position of the capstan 2 attached to the step motor 1 is selected so that it is located midway between the contact point of the A1 and A2 wheels with the guide rail 10A and the contact point of the B wheel with the guide rail 10B. . As before, if we decompose it into the forces of Pa and Pb, Pa=P・Lb/2 (La+Lb) Pb=P・La/(La−Lb) Thinking in the same way as before, the above Pa and Pb are external forces in opposite directions. As a result, a moment can be applied to the radial ball bearing 22. At this time, if 2La=Lb, then Pa=Pb=P/3 from the above equation. That is, the life of the radial ball bearing 22 can be designed to be equal as described above.

【Effect of the invention】

Since the present invention has the above-described structure and operation, it has the following superior effects compared to conventional ones. The play of the three radial ball bearings used to guide the carriage can be eliminated without adding any other parts including radial ball bearings. That is, it is possible to apply a preload force to the radial ball bearing, especially in the thrust direction, without adding any other parts. (a) Therefore, the mass of the traveling table can be reduced accordingly, and when this is applied to a magnetic disk device, the access time can be shortened. This is because the average access time is proportional to the square root of the mass of the movable part. (b) By appropriately selecting the positions of the three radial ball bearings and the position at which the steel belt is attached to the running platform, the moments acting on each of the radial ball bearings can be made equal, and the overall It can extend your lifespan. (c) Parts purchasing costs and assembly adjustment costs can be reduced. (d) Reliability can be improved because the number of parts can be reduced. (e) Also, since assembly work in a narrow space becomes easier, there are fewer restrictions on the applicable skill level, and the possibility of work errors can be reduced.

[Brief explanation of drawings]

FIG. 1a: A plan view of the first embodiment according to the present invention,
Figure 1b: Front view of the first embodiment according to the present invention and explanatory diagram of acting force, Figure 1c: First embodiment according to the present invention
A side view of the embodiment and an explanatory diagram of the acting force, FIG.
Figures: Side view and explanatory view of acting force of the second embodiment of the present invention, Figure 3a: Plane view of the conventional example, Figure 3b: Front view of the conventional example, Figure 3c: Figure 3c: Front view of the conventional example. Side view. 1: Step motor, 2: Capstan, 3:
Steel belt, 4: Running platform, 10A, 10B:
Guide rail, 21: V-grooved wheel, 22: radial ball bearing, 23: axle.

Claims (1)

[Scope of Claims] 1. A concave groove is provided on the circumferential surface, the traveling base is supported by the traveling base via a bearing that may cause play, and the traveling base is mounted between a pair of parallel guide rails that are engaged with the groove. A plurality of wheels movably guiding the guide rail in the longitudinal direction, a belt whose both ends are respectively attached between two different fixed points in the running platform, and stretched between the two fixed points; In a mechanism that includes a capstan disposed so that its peripheral surface is in close contact with the intermediate portion of the belt, and that moves a running platform along a guide rail in accordance with the rotation of the capstan, the longitudinal direction of the belt is The line connecting the two fixed points has an angle of inclination, and based on the angle of inclination and the tension of the belt, there is a line that acts on the traveling base in a direction perpendicular to the plane containing the axes of the pair of guide rails. A guide drive mechanism for a traveling platform, characterized in that a capstan is disposed at a position where a force can have an arm length of a moment with respect to each of the engagement points between the wheel and the guide rail. 2. In what is stated in claim 1,
A guide drive mechanism for a traveling platform, wherein the guide rail has an internal cross section. 3. The guide drive mechanism for a traveling platform according to claim 1 or 2, wherein the bearing is a radial ball bearing. 4. A guide drive mechanism for a traveling platform according to any one of claims 1 to 3, characterized in that the concave groove on the circumferential surface of the wheel is a V-groove. 5. In the product described in any one of claims 1 to 4, the number of wheels is three, and the triangle formed by the center of the wheel is an isosceles triangle, and one side is not equilateral. A guide drive mechanism for a traveling platform, characterized in that one guide rail is installed parallel to the guide rail. 6 In what is stated in claim 5,
A guide drive mechanism for a traveling platform characterized by having three equal wheels and three equal bearings. 7 In what is stated in claim 6,
A line of action of a component force of belt tension acting in a direction perpendicular to a plane containing the axes of the pair of guide rails engages two wheels located at both ends of equilateral sides of a triangle formed by the wheel center. A guide drive mechanism for a traveling platform, which is located on the opposite side of the triangular side of the first guide rail, and the distance between the line of action and the first guide rail is approximately equal to the guide rail interval. 8 In what is stated in claim 6,
The line of action of the component force of the belt tension acting perpendicularly to the plane containing the axes of the pair of guide rails is such that the distance between the first guide rail and the second guide rail is 1:2.
A guide drive mechanism for a traveling platform, characterized in that it is located at a position that is internally divided by a ratio of .