Optical head feeder

[0024] figure 1 It is a perspective view showing the entire disk drive device for a digital video disk (DVD) equipped with the optical head feeding device of the present invention with the back side upward. Such as figure 1 As shown, guide members (guide shafts) 18a, 18b are provided on the bottom plate S, which are parallel to each other. Between the guide members 18a and 18b, the optical head unit H on which the optical head 12 is installed is supported on the optical head base 14. In the optical head 12, light-emitting elements such as a semiconductor laser, an objective lens 12a, light-receiving elements, and other optical components are installed. The objective lens 12a collects the light emitted from the light-emitting element on the recording surface of the disc D, and the light-receiving element receives and detects the light reflected from the disc D.

[0025] The bearing sleeves 15a, 16a are embedded in the bearing parts 15, 16 integrally made on one side of the optical head base 14 (refer to figure 2 ), the guide member 18a is inserted into the bearing sleeves 15a, 16a and passes through the bearing sleeves. A U-shaped groove 17a is provided in the bearing portion 17 made on the other side of the optical head base 14. This U-shaped groove 17a is fitted on the guide member 18b and can slide freely. It is in the Y1-Y2 direction shown in the figure. Have a certain amount of activity margin. Therefore, the optical head base 14 can slide along the guide members 18a, 18b in the X1-X2 directions shown in the figure. In addition, the guide member 18a is inserted and passed between the bearing sleeves 15a, 16a with a very small gap. Therefore, the guide member 18a and the bearing sleeves 15a, 16a are hardly loose and can slide with very low friction.

[0026] A screw 11 is provided at a position adjacent to the guide member 18a, which is parallel to the guide member 18a. Both ends of the screw 11 are supported in bearing portions 11c, 11d fixed on the bottom plate S, and can rotate freely. On the X1 side of the screw 11, a tracking motor 19 is provided. The rotational force of the tracking motor 19 is decelerated by the reduction gear train 20 and then transmitted to the screw 11. In this embodiment, the tracking motor 19 and the reduction gear train 20 constitute a driving part for rotating the screw 11.

[0027] The first fitting member 21 and the second fitting member 22 are respectively provided at the end on the Y1 side as shown in the figure, and the bearing portions 15 and 16 of the optical head base 14 are also provided on this end. The first fitting member 21 and the second fitting member 22 are made of a synthetic resin material with a small friction coefficient. Such as Figure 5 As shown, on the first fitting member 21, two protrusions 21d, 21e are integrally formed, and on the second fitting member 22, two protrusions 22d, 22e are integrally formed. The respective protrusions 21d, 21e and 22d, 22e are engaged with the thread groove (thread bottom) 11a of the screw 11. The screw 11 is composed of two threads. When the above-mentioned driving part rotates the screw 11, the feeding force acts on the fitting members 21, 22 in the X1 direction or the X2 direction, so that the optical head base 14 uses the guide member 18a as The reference moves toward the radial direction of the disk D.

[0028] On the X1 side of the bottom plate S, a spindle motor M is fixed. The motor shaft Ma of the spindle motor M penetrates the bottom plate S and protrudes in the direction Z2 as shown in the figure. Under the bottom plate S, at the front end of the motor shaft Ma, a turntable Ta is installed, and the disk D can be installed on the turntable Ta.

[0029] When the disc D is placed on the turntable Ta and the reproduction or recording mode is set, the spindle motor M is driven to rotate, causing the disc D to rotate. In addition, the optical head feeding device composed of the fitting members 21, 22 and the screw 11 allows the optical head device H to face the disk D from a position opposite to the TOC area provided on the inner circumference of the recording surface of the disk D The outer circumference side (X2 side) of the disk is moved to read the signal on the recording surface of the disk D or record the signal on the recording surface of the disk D.

[0030] figure 2 Represents the optical head feeding device of the present invention, which is from figure 1 An enlarged exploded perspective view from the direction of the II arrow, image 3 To represent figure 2 An enlarged cross-sectional view of the optical head feeding device shown in the assembled state, cut along the Y-Z plane, Figure 4 For figure 2 The enlarged plan view of the optical head feeding device viewed in the direction of the Z2 arrow, Figure 5 For figure 2 An enlarged front view of the optical head feeding device seen in the direction of the Y2 arrow.

[0031] The optical head base 14 and the bearing parts 15, 16 of the above-mentioned optical head component H, for example, can be formed by die-casting metal such as aluminum alloy. Under the bearing parts 15, 16 (in figure 1 , 2 is the upper surface) is provided with a flat spring 23 as an elastic pressing member. Screws 26, 26 inserted and passed through the mounting holes 23a, 23a of the plate spring 23 are tightened in the female threaded holes 15b, 16b made on the bearing parts 15, 16 to fix the plate spring 23 to the optical head base 14. on.

[0032] The flat spring 23 is formed by pressing a thin metal plate spring material, and the bent portion thereof becomes a handle 23c and a hoop 23d extending in the Y1 direction in the figure. In addition, a corner hole 23b is formed in the central portion of the handle 23c. The first fitting member 21 is made of synthetic resin, the end of the handle 23c of the flat spring 23 is embedded in the first fitting member 21, and the flat spring 23 and the first fitting member 21 are fixed as a whole.

[0033] On the fitting portion 21a of the first fitting member 21, as described above, two protrusions 21d and 21e are formed at predetermined intervals. The ridges 21d, 21e are formed obliquely with respect to the axial direction (X direction) of the screw 11 at an angle along the helical inclination direction of the screw groove (the bottom of the screw) 11a of the screw 11, or are formed with the screw The spiral trajectory of the groove 11a is a spiral shape. The screw 11 is composed of two threads, and the protrusions 21d, 21e are formed at an interval of 1.5 times the pitch of the two threads, and are fitted into spiral grooves (thread grooves) of the screw 11 on mutually different trajectories.

[0034] In addition, in figure 2 A protruding pivot 21c is formed on the upper surface of the first fitting member 21 shown. The center line O1 of this support shaft 21c is perpendicular to the center line O2 of the shaft of the screw 11, and the extension line of the above-mentioned center line O1 intersects the shaft center line O2 of the screw 11.

[0035] Such as figure 2 As shown, the revolving portion 22a, the fitting portion 22c and the connecting portion 22b of the second fitting member 22 are integrally made of synthetic resin. A hole 22a1 is formed in the revolving part 22a, which can be inserted and fitted with the above-mentioned support shaft 21c and can be rotated freely, and at the other end of the revolving part 22a, another hoop 22a2 is integrally formed. The connecting portion 22b of the rotating portion 22a passes through the corner hole 23b of the flat spring 23 and extends in the Z2 direction in a state where it can be inserted into and passed through the support shaft 21c freely. In this way, the fitting portion 22c is in a direction opposite to the fitting portion 21a of the first fitting member 21 with respect to the screw 11, and is in a direction opposite to the screw 11.

[0036] On the fitting portion 22c, the two protrusions 22d and 22e are integrally formed. Such as Figure 4 As shown, these two protrusions 22d, 22e are also made obliquely with respect to the axial direction (X direction) at an angle along the spiral shape of the thread groove (bottom of the thread) 11a of the screw 11, or made with The spiral shape of the thread groove 11a is the same. Such as Figure 5 As shown, the distance between the protrusions 22d and 22e is one pitch of the two thread grooves of the screw 11. The protrusions 22d and 22e are respectively fitted in spiral grooves (thread grooves) of the same track of the screw 11.

[0037] Between the ferrule 22a2 of the second fitting member and the ferrule 23d of the flat spring 23, an urging member 24 such as a coil spring is bridged. In this way, since the ferrule 22a2 of the second fitting member 22 is always subjected to the abutting force in the X2 direction shown in the figure, the second fitting member 22 can be rotated and abutted in the β direction. Therefore, at Figure 5 The protrusions 22d, 22e of the second fitting member 22 on the lower side have an abutting force component acting in the F1 direction, and are elastically pressed against the side surface of the thread 11b of the screw 11, and on the contrary, they are located Figure 5 The protrusions 21d and 21e of the first fitting member at the upper end have an abutting force component acting in the F2 direction, and are elastically pressed against the side surface of the thread 11b.

[0038] Since the first fitting member 21 and the second fitting member 22 have mutually opposite contact force components F1 and F2 with respect to the axial direction of the screw 11, and are engaged with the screw 11, they can be absorbed in the fitting member 21 , 22 and the screw 11, therefore, the optical head component H will not loosen in the X1-X2 direction of the moving direction. In addition, even if the projections 21d, 21e of the first fitting member 21 and the second fitting member 22 are the projections 22d, 22e, there is a forming error, or due to long-term use, these projections are caused by sliding Wear, due to Figure 5 The shown abutment force components acting in the direction of F1 and F2 continue to act on each protrusion, so the gap will not increase.

[0039] Such as image 3 As shown, the opposing interval h between the fitting portion 21a of the first fitting member 21 and the fitting portion 22c of the second fitting member 22 is determined by the assembly dimensions of the two fitting members 21 and 22. Therefore, by sufficiently ensuring the rigidity of the connecting portion 22b and the like of the second fitting member 22, it is possible to prevent the opposing interval h between the fitting portions 21a, 22c from being expanded beyond the set value. In this way, when the above-mentioned opposing interval h is set to a size such that the protrusions 21d, 21e and the protrusions 22d, 22e cannot escape from the groove 11a of the screw 11, even if there is an excessive impact, it acts on the X direction In the optical head unit H, the two fitting members 21 and 22 will not come out of the groove 11a of the screw 11. Therefore, even if the optical head 12 is a heavy optical head used for DVDs or the like, the impact does not cause the optical head component H to move in the X direction.

[0040] In addition, the elastic pressing force of the flat spring 23 causes the first fitting part 21 to elastically press against the screw 11 in a direction perpendicular to the shaft center O2, so that the relative position of the guide member 18a and the screw 11 can be absorbed. Assembling error and parallelism error, so there is no need for great elastic pressing force. That is, since the gap between the two fitting members 21, 22 and the screw 11 is absorbed by the elastic force of the urging member 24, there is no need to use excessive force to elastically the first fitting member 21 Press on the screw 11. Therefore, even if the elastic pressing force of the flat spring 23 exerts a large lateral pressure on the bearing portions 11c, 11d of the screw 11, the rotation load will not increase. In addition, by elastically pressing the first fitting member 21 on the screw 11 with a certain force, the effect of eliminating the gap can be further improved.

[0041] In addition, the respective protrusions 21d, 21e and 22d, 22e are elastically pressed against each other on the thread 11b of the screw 11 in the X direction, and slide, because this is obliquely affected by the tight force in the F1 and F2 directions. Because of the sliding caused by the pressing surface, the rotational load of the screw 11 caused by sliding friction is also small.

[0042] In addition, since the center line O1 of the support shaft 21c, which is the center of rotation of the second fitting member 22, is located at a position intersecting the shaft center line O2 of the screw 11 in the cross-sectional position of the screw 11, as Figure 4 As shown, the arrangement space of the fitting members 21 and 22 can be made into a small area on the plane, so that the optical head feeding device can be miniaturized.

[0043] As described above, when the present invention is used, no excessive rotation load is applied to the screw, and the gap between the fitting member provided on the optical head component and the screw can be reduced or completely eliminated. In addition, the fitting member does not come out of the screw in the axial direction of the screw. Therefore, it is possible to provide an optical head feeding device that has strong resistance to external shocks.