JP2541648Y2 - Carrier mechanism - Google Patents

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier mechanism suitable for driving a driven body such as a carriage of an optical disk drive.

2. Description of the Related Art For example, a carriage of an optical disk device or the like is required to have a high accuracy of about 1 / 10,000 radian in characteristics such as pitching, yawing, and rolling. In order to slide such a carriage, six bearings are required for a standard bearing, and three bearings are required for an outer grooved bearing.
Therefore, in order to reduce the size of the drive mechanism, it is inevitable to use bearings with outer grooves. However, when bearings with outer grooves are used in the usual way, they are affected by the angular clearance, and the range of angular clearance is limited. Because of the swing, the characteristics of the accuracy described above cannot be obtained at all. In order to eliminate such an adverse effect on the driving characteristics of the angular clearance, it has been proposed to operate the bearing in a state where the bearing is deviated to the limit of the angular clearance, as shown in FIGS. 6 and 7. There is something. In FIG. 6, 1A, 1
Reference numerals B and 1C denote bearings with outer grooves having a structure as shown in FIG. 8, which are attached to the carriage 2 by shafts fitted into respective inner rings. Outer groove bearing 1A-1C
Is supported by the two guide shafts 3A and 3B and travels by an external driving force. Here, an outer groove bearing 1 shown in FIG. 8 has an outer ring 1b having an outer groove 1a and an inner ring 1c.
And a plurality of balls 1d rolling between the rolling grooves of the outer ring and the inner ring
The shaft 4 is fixed to the inner ring 1c. In such a conventional bearing 1 with an outer groove, the center of the outer groove 1a and the centers of the respective rolling grooves of the outer ring 1b and the inner ring 1c are substantially on the same line XX '.
And the center of the guide shafts 3A 'and 3B' is also substantially the same line X.
On X '. However, the bearings have various types of clearances, and the bearings with the outer grooves also swing in a certain angle range with respect to the line XX 'depending on the size of the angular clearance. In the apparatus shown in FIG. 6 using the above, a preload mechanism 5 is arranged on the carriage 2 to apply a preload as indicated by an arrow. By applying a load in this way,
Each of the outer grooved bearings 1A to 1C will always be displaced to the limit of its own angular clearance, and therefore these outer grooved bearings 1A to 1C will move within their respective angular clearance ranges. It does not work while swinging. Next, in the conventional example shown in FIG. 7, the mounting level of the outer grooved bearings 1A, 1B, and 1C is stepped, and a preload is applied from the side in the driving direction as shown by the arrow to reduce the angular clearance. This is to remove backlash. In this example, since the mounting level of the outer grooved bearings 1A, 1B, and 1C is stepped, when a load is applied in the direction of the arrow, the load acts as a downward force on the outer ring, and the above conventional example is used. alike,
The outer grooved bearings 1A to 1C operate in a state of being deviated to the limit of each angular clearance.

However, such a conventional apparatus has the following disadvantages. (1) Because the unit price of the outer grooved bearing, which is a component, is expensive,
The equipment becomes expensive. (2) Due to the large volume of the outer grooved bearing as a component,
The device becomes larger. (3) Responsiveness is poor due to heavy weight and large inertial force. (4) The carriage must be machined in advance so as to form a step having a step, so that it is difficult to improve the accuracy of the carriage.

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned drawbacks, the present invention has a plurality of circumferentially arranged first balls and a single ball arranged in contact with the first balls. A pair of cups accommodating a second ball therein, a guide shaft disposed between the pair of cups disposed facing each other so as to contact the second ball, and fixing the cups And a carrier mechanism comprising:

FIG. 1 is a diagram for explaining an embodiment of the present invention. In the figure, a cup 6 is fixed to a carriage 2 by press-fitting or bonding. Then, a plurality of first balls 7 are circumferentially arranged inside the cup 6. Here, if necessary, the first balls 7 can be arranged at equal intervals by using a retainer. A plurality of first balls 7
, And the single second ball 8 is brought into contact angle 15 °
Place at 35 °. The first ball 7 and the second ball 8 are configured to cover the spherical surfaces of the first ball 7 and the second ball 8 so as to prevent the first ball 7 and the second ball 8 from falling off.
A shield plate 9 configured such that the ball 8 contacts the guide shaft 3 is fixed to the cup 6. The cups having such a configuration are arranged to face each other via the guide shaft 3. One of a plurality of sets of cups configured as described above is mounted and arranged on a preloading device 10 made of a preload means, for example, a spring plate, and the preloading device 10 is mounted on the carriage 2 by screws 11. With this simple preloading fitting 10, the conventional complicated preloading mechanism 5 can be omitted, so that the apparatus is further downsized. The shield plate 9 is provided for convenience in assembling and can be omitted. Next, the operation will be described as follows. When the carriage 2 is operated in the longitudinal direction of the axis of the guide shaft 3, the second ball 8 moves while rotating on the guide shaft 3. When the second ball 8 rotates, the first ball 7 moves in conjunction with the cup 6.
Revolves while rotating on the inner diameter surface of. The first ball 7 attached to the preloading member 10 performs the same operation, but the preloading member 10 brings the guide shaft 3 into a constant pressure preload state. Thus, the axial gap and the radial gap of the entire carrier mechanism can be removed. Further, since the accuracy of the entire bearing is determined only by the accuracy of the second ball 8, a design utilizing the sphericity of the second ball 8 can be made, and the sphericity of the second ball 8 can be reduced. By raising, the axial run-out and the radial run-out can be reduced. Therefore, as a result, a carrier mechanism having a rolling mechanism is provided, so that a coil can be attached to the carriage 2 and a magnet can be arranged around the guide shaft 3 to function as a voice coil motor. Further, since the weight is light, the inertial force is small, and since the first ball 7 and the second ball 8 are rolling, the torque is small, so that high-speed positioning is possible if used for the head positioning of the optical disk device. Incidentally, the contact point of the first ball 7 with the cup 6 does not need to be one point as in the above embodiment, but may be two points as shown in FIG. In the case of two points, the seating of the first ball 7 is good, and the hysteresis is improved. FIG. 3 shows another embodiment of the present invention. In this embodiment, instead of the second ball 8, circumferential grooves 12 are provided at both ends so as to contact the first ball.
a, and a receiving seat 12 in which a circumferential groove 12b is formed in a central portion so as to contact the guide shaft 3 is used. In this embodiment, the contact area between the receiving seat 12 and the guide shaft 3 and the contact area between the receiving seat 12 and the first ball 7 are increased, so that stress can be relaxed and the life is prolonged. Others are the same as those described in the embodiment of FIG. 1, and the same effects can be obtained. FIG. 4 shows another embodiment of the present invention. In this embodiment, the cup 6
Are arranged face-to-face instead of face-to-face (parallel) as in the embodiment of FIG.
In this embodiment, the machining of the carriage 2 is a simultaneous machining from the side, so that the accuracy and the assembling are facilitated. Others are the same as those described in the embodiment of FIG.
Similar effects can be obtained. FIG. 5 shows another embodiment of the present invention. In this embodiment, a rectangular guide shaft is used as the guide shaft 3. This embodiment is also the same as that described in the embodiment of FIG. 1, and the same effects are obtained. In the embodiment of FIGS. 2 to 5, the shield plate 9 can be fixed to the cup 6 as necessary, similarly to the embodiment of FIG.

According to the present invention, the following effects can be obtained. (1) It is a small and inexpensive device because it is composed of small and simple processed parts. (2) Light weight and good responsiveness. (3) Axial runout and radial runout are small and high accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention.

FIG. 2 is a view for explaining an embodiment of the present invention;

FIG. 3 is a diagram illustrating an embodiment of the present invention;

FIG. 4 is a diagram illustrating an embodiment of the present invention.

FIG. 5 is a view for explaining an embodiment of the present invention;

FIG. 6 is a diagram for explaining a conventional example.

FIG. 7 is a diagram for explaining a conventional example.

FIG. 8 is a diagram for explaining a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Bearing with outer groove 1a ... Outer groove 1b ... Outer ring 1c ... Inner ring 1d ... Ball 2 ... Carriage 3 ... Guide shaft 4 ... Shaft 5 ... Preload mechanism 6 ... Cup 7 ... 1st ball 8 ... 2nd ball 9 ... Shield plate 10 Preload means 11 Screw 12 Receiving seat 12a, 12b Circumferential groove

Claims (6)

(57) [Scope of request for utility model registration] A pair of cups accommodating therein a plurality of first balls arranged circumferentially and a single second ball arranged in contact with the first balls; A carrier mechanism, comprising: a guide shaft disposed between the pair of cups disposed facing each other so as to contact the second ball; and a carriage to which the cups are fixed. 2. A pair of cups accommodating a plurality of first balls arranged circumferentially therein, and the pair of cups contacting the first balls by circumferential grooves formed at both ends. A receiving shaft disposed between the cups, a guide shaft disposed so as to contact a circumferential groove formed in a center portion of the receiving seat, and a carriage fixing the cup. A carrier mechanism. 3. A cup pair containing a plurality of circumferentially arranged first balls and a single second ball arranged in contact with the first balls, and A carrier mechanism, comprising: a guide shaft disposed so as to contact between the second balls of the pair of cups arranged in tandem; and a carriage to which the cups are fixed. 4. A contact angle between the first ball and the second ball is 15 ° to 35 °.
Or the carrier mechanism according to 3. 5. A preload means for preloading at least one of said cups.
The carrier mechanism according to any one of the above. 6. The carrier mechanism according to claim 5, wherein said preload means comprises a springy plate.