JPH064452Y2 - Carriage drive of magnetic disk device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a drive device for a carriage equipped with a magnetic head in a magnetic disk device for magnetically recording information on a magnetic disk. The carriage is provided with a lead screw and a needle. The present invention relates to a feeding device, in particular, a structure for pressing the needle against the lead screw.

[Prior Art] FIG. 2 shows, for example, Mitsubishi Electric Technical Report Vol.59 No.12 (198).
It is a perspective view which shows the conventional carriage drive device of this kind shown by 5). In the figure, reference numeral (1) is a step motor, (2) is a lead screw integrated with the rotor of the step motor (1), (3) is a needle pressed by the lead screw (2), and (4) is this. Insert needle (3) into lead screw (2)
A moving pressure leaf spring that presses against the needle, (5) a carriage on which the needle (3), the moving pressure leaf spring (4) and a magnetic head (not shown) are mounted, and (6) linearly moves the carriage (5). It is a guide rod.

Next, the operation will be described. When the step motor (1) rotates, this rotation causes the lead screw (2) integral with the rotor of the step motor (1) to rotate. Third
As shown in the figure, the needle (3) is fitted into the thread of the lead screw (2) by the moving pressure leaf spring (4), so the needle (3) corresponds to the rotation of the lead screw (2). Then
It is moved in the axial direction of the lead screw (2). Needle (3)
Is fixed to the carriage (5), and the needle (3) and the carriage (5) move together. Further, the carriage (5) performs a linear movement along the guide rod (6). At this time, the load torque of the step motor (1) is
The frictional force between the moving pressure leaf spring (4) and the lead screw (2) is expressed by the following equation.

_{T 1 = {Fsinβ / cosβ +} μ N Pcosβ / sinα + μ
_P P} (1) where: T ₁ ; load torque of this conventional example F; load of carriage (5) β; lead angle of lead screw (2) α; angle of thread of lead screw (2) Yes, as shown in Fig. 3, perpendicular to the center line (10) of the lead screw (2)
Angle formed by (11) and thread μ _N ; Coefficient of friction between needle (3) and lead screw (2) μ _P ; Coefficient of friction between moving pressure leaf spring (4) and lead screw (2) P; Moving pressure leaf spring Pressurization force due to (4) r; pitch radius, which is the distance from the contact point between the needle (3) and the thread of the lead screw (2) to the central axis (10) of the lead screw (2).

The lead angle β is the inclination angle of the screw of the lead screw (2) as shown in FIG.
If the lead, which is the straight travel distance obtained by rotation, is L, L =
It is an angle having a relationship of 2πrtanβ.

Next, a process of deriving the equation (1) indicating T ₁ will be described.

First, the generation process of Fsinβ / cosβ will be described with reference to FIG. Incidentally, FIG. 4 is a view of the lead screw (2) viewed from above.

The traveling direction of the carriage (5) is x. Then, when the lead screw (2) is rotated counterclockwise as shown by the arrow (12) in the x direction, the needle moves from the lead screw (2).
The load F of the carriage (5) acts on (3) and the carriage
Go straight on (5) in the x direction. At this time, the thread surface is xy
Since the lead angle β is inclined in the plane, the component of the force generated on the thread surface in the xy plane is F / cos β, and x
It is inclined by β from the axis. And this y of F / cos β
The direction component is Fsinβ / cosβ.

Since the needle (3) acts on the lead screw (2) in the opposite direction due to the action-reaction relationship, the step motor
For (1), it becomes the load torque, and its value is {Fsinβ /
cosβ} r.

Next, the generation process of μ _N Pcos β / sin α will be described with reference to FIGS. 5 and 6. Fig. 5 shows the lead screw (2)
It is explanatory drawing by the axial direction cross section of FIG. Moving pressure leaf spring (4)
The pressing force P due to is applied from the needle (3) to the lead screw (2).
Act on. At this time, if the force acting on the thread surface of the lead screw (2) is R, then R = P / 2sinα.

In this relationship, when P and R on the right side are moved in parallel as shown by a broken line, the triangle formed by R on the left side and P, R on the broken line becomes an isosceles triangle. Therefore, P / 2 = Rsinα, which is easily obtained.

The force R causes a sliding resistance of μ _N R = μ _N P / 2sinα, that is, a frictional force, in the plane where the needle (3) is in contact with the thread surface. This friction force μ _N R
One side (left side of FIG. 5) is shown in FIG. FIG. 6 is a view of the lead screw (2) seen from above, as in FIG. Since the thread surface is inclined by the lead angle β in the xy plane, the load torque component due to μ _N R is {μ _N Rcos
β} r. As shown in FIG. 5, μ _N R acts on the left side and the right side of the screw thread, so that the load torque component due to the pressing force P is {2μ _N Rcosβ} r = {2μ _N (P / 2sinα ) Cos
β} r = {μ _N Pcos β / sin α} r.

μ _P P is a sliding resistance, that is, a frictional force due to the contact between the moving pressure leaf spring (4) and the lead screw (2), and μ _P Pr
Is a load torque associated with the frictional force. The load torque is approximated by using the pitch circle radius r instead of the distance from the central axis (10) of the lead screw (2) to the crest of the screw thread.

[Problems to be Solved by the Invention] Since the conventional carriage drive device of the magnetic disk device is configured as described above, there is a problem that the load torque of the step motor increases due to the frictional force between the pressure leaf spring and the lead screw. was there.

The present invention has been made to solve the above-mentioned problems, and provides a carriage drive device for a magnetic disk device capable of removing the frictional force between the pressure leaf spring and the lead screw and reducing the load torque to the step motor. The purpose is to get.

[Means for Solving the Problems] A carriage drive device of a magnetic disk device according to the present invention includes a carriage on which a magnetic head is mounted, a needle fixed to the carriage, and a lead screw rotated by a drive source. In a carriage drive device of a magnetic disk drive, which comprises a pressurizing means for pressing a needle to the lead screw, and the carriage is driven via the needle by the rotation of the lead screw, the pressurizing means has one end magnetically driven. The pressure plate spring is fixed to the housing of the disk device and has the other end elastically pressing the needle. The needle slides with respect to the pressure plate spring by the rotation of the lead screw.

[Operation] In this invention, since the pressure leaf spring that presses the needle against the lead screw does not contact the lead screw, the friction force between the pressure leaf spring and the lead screw is removed, and the step motor that is the drive source of the lead screw is removed. Load torque is reduced.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, reference numerals (1), (2), (3), (5), and (6) are exactly the same as those of the conventional device, and (7) is the needle (3) on the lead screw (2). It is a fixed pressure leaf spring that is pressed. (8) is an outer box for fixing one end of the fixed pressure leaf spring (7), and the outer box (8), that is, the housing of the magnetic disk device, also includes the step motor (1) and the guide rod (6). It is fixed.

In the carriage driving device configured as described above, the other end of the fixed pressure leaf spring (7) elastically presses the needle (3), and the needle (3) does not contact the lead screw (2).
Press on the lead screw (2). The needle (3) moves while sliding on the fixed pressure leaf spring (7) by the rotation of the lead screw (2). At this time, step motor (1)
The load torque of is expressed by the following equation.

T ₂ = {(F + μ _G P) sin β / cos β + μ _N P cosβ / s
in α} r (2) where T _{2 is} the load torque μ _G of this embodiment; the coefficient of friction between the fixed pressure leaf spring (7) and the needle (3).

In equation (2), {Fsinβ / cosβ} r is the carriage
The load torque associated with the load F in (5), which is the same value as that in equation (1).

{Μ _N Pcos β / sin α} r is a load torque caused by the pressure applied by the fixed pressure leaf spring (7) acting on the lead screw (2) from the needle (3), and is the needle (3) to the lead screw (2). Since the pressure applied by the fixed pressure leaf spring (7) acting on () is the same as the pressure applied by the moving pressure leaf spring (4) in the conventional example, its value is the same as that of the equation (1).

{Μ _G Psinβ / cosβ} r is a sliding resistance of the fixed pressure leaf spring (7) and the needle (3), that is, a load torque due to a frictional force, which will be described below.

Frictional force of the fixed pressure plate spring (7) and the needle (3) is mu _{G P,} and this force mu _{G P} acts on the lead screw (2) via the needle (3). Therefore, similarly to the load F of the carriage (5) in the above equation (1), the load torque by μ _G P is {μ _G Psinβ / cosβ} r.

As explained above, the load torque T ₂ of this embodiment is
Since the equation (2) is obtained, the difference ΔT from the load torque T ₁ of the conventional example represented by the equation (1) is given by the following equation.

ΔT = T ₁ −T ₂ = (μ _P −μ _G sinβ / cos β) Pr For example, in the case of β = 9 °, μ _P = 0.1, μ _G = 0.3, μ
_{P -μ G sinβ} / _cosβ ≒ 0.05, and the since Pr is the same as the conventional example, the load torque by the pressure plate spring conventional example
It can be reduced to about 1/2.

[Advantages of the Invention] As described above, according to the present invention, the carriage on which the magnetic head is mounted, the needle fixed to the carriage, the lead screw rotated by the driving source such as the step motor, and the lead screw are provided. In the carriage drive device of the magnetic disk device, wherein the carriage is driven via the needle by the rotation of the lead screw, the pressurizing means has one end of the magnetic disk device. Fixed to the housing, and
The other end is composed of a pressure leaf spring that elastically presses the needle, and the needle moves while sliding with respect to the pressure leaf spring due to rotation of the lead screw.Therefore, press the needle against the lead screw with a member that does not contact the lead screw. You can

Therefore, the load torque of the drive source can be reduced, the apparatus can be made inexpensive or compact, and the carriage moving speed can be increased.

[Brief description of drawings]

FIG. 1 is a perspective view of a carriage driving device of a magnetic disk device showing an embodiment of the present invention, FIG. 2 is a perspective view of a conventional carriage driving device, and FIG. 3 is a lead screw of a conventional carriage driving device. Sectional view of a state where a needle is fitted to a screw thread, FIG. 4 is an explanatory view for explaining a generation process of F sin β / cos β, FIG. 5 is an explanatory view for explaining a generation process of μ _N P cos β / sin α, and FIG. Is μ _N Pcos β / sin α
FIG. 8 is another explanatory diagram illustrating a process of occurrence of the. In the figure, (1) is a step motor, (2) is a lead screw, (3) is a needle, (5) is a carriage, (7) is a fixed pressure leaf spring, and (8) is an outer box. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] 1. A carriage equipped with a magnetic head, a needle fixed to the carriage, a lead screw rotated by a drive source, and a pressurizing means for pressing the needle to the lead screw. In a carriage driving device of a magnetic disk device, wherein the carriage is driven via a needle by rotation of a lead screw, one end of the pressing means is fixed to a housing of the magnetic disk device, and the other end Is composed of a pressure plate spring for elastically pressing the needle, and the needle moves while sliding with respect to the pressure plate spring by the rotation of the lead screw.