KR19990042774A - Overload Breaker of Projector Projection Lens Driving Motor - Google Patents

Abstract

The present invention relates to an overload blocking device of a driving motor for driving a projection lens for focusing and zooming of a projector. The present invention relates to a direction perpendicular to an axial direction by interfering with a protrusion installed on a side of a driving gear and rotating with the driving shaft. In the overload blocking device of the projector projection lens driving motor having an "┐" shape elastic member that is elastically deformed, the interference force between the protrusion and the elastic member is increased so that the protrusion part overcomes the elastically deformed elastic member. It is provided with a switching means for switching the power of the drive motor by the pressing of the elastic member.

Therefore, according to the present invention, it is possible to obtain an effect of suppressing impact noise and extending product life by preventing idling in an overload state.

Description

Overload Breaker of Projector Projection Lens Driving Motor

The present invention relates to an overload cut-off device of a projector projection lens drive motor, and more particularly, to an overload cut-off device of a drive motor having a switching means for stopping the operation of the drive motor when the drive motor is overloaded. .

In general, a device for projecting optical energy onto a screen includes a direct-view image display device and a projection-type image display device according to a method of displaying optical energy on a screen. type image display device).

An example of a direct-view image display apparatus is a cathode ray tube (CRT), which is a so-called CRT device, which has excellent image quality but increases in weight and volume as the size of the screen increases, leading to an increase in manufacturing cost. There is.

Projection type image display devices are referred to as liquid crystal displays (hereinafter referred to as LCDs), deformable mirror devices (hereinafter referred to as DMDs), and actuated mirror arrays (hereinafter referred to as AMAs). ).

Since the LCD has a very simple optical structure, it can be thinly formed to reduce the weight and the volume. However, due to the polarity of light, the light efficiency is low, and there is a problem inherent in the liquid crystal material, for example, a slow response speed and a disadvantage in that the inside is easily overheated. In addition, the maximum light efficiency of existing transmission light modulators is limited to a range of 1 to 2% and requires dark room conditions to provide acceptable display quality.

Optical modulators such as DMD and AMA have been developed to solve the problems of the aforementioned LCD type optical modulators.

DMD shows a relatively good light efficiency of about 5%, but serious fatigue problems are caused by the hinge structure employed in the DMD. In addition, there is a disadvantage that a very complicated and expensive driving circuit is required.

In contrast, AMA is a piezoelectrically driven mirror array that provides light efficiency of 10% or more. In an AMA light modulator, each actuator generates a deformation in accordance with an electric field generated by an applied electric image signal and a bias voltage. When the actuator causes deformation, each of the mirrors mounted on the actuator is inclined to reflect the light incident from the light source at a predetermined angle.

The AMA optical modulator has a simple structure and operation principle, and can obtain high light efficiency compared to LCD or DMD. It also provides enough contrast to provide a bright and clear image under normal room temperature light conditions. Moreover, it is not only affected by the polarity of the incident light, but also by the polarity of the reflected light. In addition, the reflective properties of the AMA are relatively less sensitive to temperature, which has the advantage of improving the brightness of the screen compared to other devices that are easily affected by high power light sources.

As shown in Fig. 1, the previously-applied projection type image display apparatus includes a lamp assembly 1 for radiating high-brightness white light, a barrel lamp 3 for paralleling rays radiated from the lamp assembly 1, A source stop (4) formed with a hole to determine the amount of light radiated from the lamp assembly (2), and a source mirror for reflecting the light beam passing through the source stop (4) in the direction of the AMA module assembly (5); 6), a dichroic filter (2) which separates white light into main beams and reflects or transmits them to each AMA module assembly (5), and an AMA panel which changes the optical path of the main beams incident upon the action of a piezoelectric actuator ( 5), a projection stop (not shown in the figure) for limiting the transmission amount of the main beams whose light path is adjusted, a projection lens 7 installed for projecting the synthesized main beams in the direction of the screen, and for incorporating these components Ke It consists of the easy 8.

The projection lens 7 is provided with a projection lens driving device capable of performing a focusing operation for adjusting the focus of an image formed on the screen and a zooming operation for adjusting the magnification of the screen, and the driving device is overloaded. Overload breaker is included to prevent damage.

An example of such an overload blocking device is described in patent application No. 96-72666 filed previously on December 27, 1996 by the applicant.

FIG. 2 is a cross-sectional view showing an example of an overload circuit breaker applied by the applicant in advance, and FIG. 3 is a cross-sectional view taken along the line AA ′ of FIG. 2, and a plurality of set screws S1 and S2 and a connector ( The drive shaft 120 connected to the motor shaft 102 in a straight line by the 104 is provided.

The drive shaft 120 is rotatably supported via the bush 106 on the other side of the bracket 110, one side of which is fixed to the motor 100.

In addition, a drive gear 140 is rotatably inserted on the drive shaft 120, and a torsion bar 142 is provided with a torsional deformation by an external force to protrude in the axial direction on the side of the drive gear 140. The support member 146 is installed at the tip of the torsion bar 142 by extending a predetermined distance inward in the radial direction, and a roller 146 rotated in parallel with the axial direction is installed at the tip of the support member 146.

On the other hand, the projection 122 is provided in a direction perpendicular to the drive shaft to cause interference with the roller 146.

Therefore, as the driving shaft 120 rotates as the motor 100 rotates, the protrusion 122 of the driving shaft 120 interferes with the roller 144 mounted on the torsion bar 142 of the driving gear 140. While keeping close contact, the drive gear 140 is transmitted to the drive gear 140 so that the drive gear 140 rotates.

On the other hand, when the overload state and the interference force between the protrusion 122 and the roller 144 gradually increases, a torsional deformation occurs in the torsion bar 142, the position of the roller 144 is pushed, the protrusion 122 is When passing through the roller 144, the rotational force of the drive shaft 120 is not transmitted to the drive gear 140 to be idling. Therefore, damage to the motor 100 due to overload is prevented. The torsion of the torsion bar 142 is appropriately adjusted in consideration of the state in which the motor 100 is overloaded.

By the way, the conventional drive motor overload cut-off device is blocked from being transmitted to the drive gear 140, the power of the drive shaft 120, but the drive shaft 120 is in a state of being continuously rotated projections (one installed on one end of the drive shaft 120 ( Since the 122 repeatedly swings and collides with the roller 144 of the torsion bar 142, there is a problem of discomfort due to impact noise and premature failure of the torsion bar 142 or the protrusion 122.

Therefore, the present invention is to solve such a conventional problem, by stopping the rotation of the drive shaft provided with a switching means that can cut off the power of the motor when the protrusion overcomes the roller of the torsion bar due to the overload condition It is an object of the present invention to provide an overload cut-off device for a driving motor that can prevent shock noise and premature failure of a torsion bar or arm.

The present invention for realizing the above object is a drive motor, a drive shaft connected in a straight line to the motor shaft of the drive motor and the projection is installed in the radial direction around the drive, and the drive is rotatably installed on the drive shaft An overload of a projector projection lens drive motor having a gear and a "┐" shaped elastic member which is provided on a side of the drive gear and interferes with a protrusion that is rotated together with the drive shaft to elastically deform in a direction perpendicular to the axial direction. In the blocking device, it characterized in that it comprises a switching means for switching the power of the drive motor by the pressing of the elastic member in a position where the interference force between the protrusion and the elastic member is increased to overcome the elastic member of the elastic deformation. .

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings by those skilled in the art.

1 is a conceptual diagram illustrating a projector related to the present invention;

Figure 2 is a cross-sectional view showing a conventional overload breaking device,

3 is a cross-sectional view taken along line AA ′ of FIG. 2;

4 is a cross-sectional view showing an overload blocking device according to the present invention;

5 is a cross-sectional view taken along line BB ′ of FIG. 4.

<Description of Symbols for Main Parts of Drawings>

10; Drive motor 20; driving axle

22; Projection 24; roller

40; Drive gear 42; Horizontal bar

44; Vertical bar 46; roller

50; Switching means

Hereinafter, an overload blocking device of a projector projection lens driving motor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4 is a cross-sectional view illustrating an overload cut-off device of a driving motor according to the present invention, and FIG. 5 is a cross-sectional view taken along the line B-B 'of FIG. 4 and includes a driving motor 10 for driving a projection lens of a projector. A plurality of set screws (S1) (S2) and the connector 14 is provided with a drive shaft 20 connected in a straight line with the motor shaft (12).

The drive shaft 20 is rotatably supported via the bush 16 on the other side of the bracket 10, one side of which is fixed to the motor 10. The drive gear 40 is rotatably installed on the drive shaft 20. Protruding portion 22 is installed in the circumference of the drive shaft 20 in the radial direction. At the tip of the projection 22, a roller 24 is provided to be rotatable in a direction parallel to the rotational direction of the drive shaft 20.

On the other hand, one side of the drive gear 40, the elastic member made of a "┐" shape to cause an elastic deformation in a direction perpendicular to the direction of the drive shaft 20 by causing interference with the roller 24 of the protrusion 22 Is installed.

The elastic member is composed of a vertical bar 42 and a horizontal bar 44 with respect to one side of the drive gear, the roller 46 is rotated while interfering with the roller of the protrusion 22 at the tip of the horizontal bar (44) Is installed.

Any one of the vertical bar 42 and the horizontal bar 44 has an elastic function in the direction perpendicular to the drive shaft by the interference with the projection. For example, the vertical bar 42 may be a torsion bar in which a torsional deformation occurs so that the vertical bar 42 has an elastic function. In addition, the horizontal bar 44 may be formed of a spring bar having an elastic function in the horizontal direction.

The interference force is increased between the roller 24 of the protrusion 22 and the roller 46 of the horizontal bar 44 so that the protrusion 22 overcomes the vertical bar 42 or the horizontal bar 44 which is elastically deformed. The switching means 50 is installed in such a position that the operation of cutting off the power of the drive motor is performed. Since the switching means 50 are driven in the forward and reverse directions of the drive shaft 20, they are symmetrically installed at both ends of the horizontal bar 44. The switching means 50 is made of a micro switch that is turned on / off by pressing or contacting the torsion bar 42.

Hereinafter, the operation of the overload blocking device of the projector projection lens driving motor according to the present invention will be described.

The driving gear 40 to which the driving force of the driving motor 10 is transmitted is not shown in the drawing, but is coupled to the circumferential surface of the focusing adjustment cap or the zoom adjustment cap, for example, an adjustment cap equipped with projection lenses of the projector. have. The drive motor 10 and the drive gear 40 may be provided in a plurality of separately provided in each adjustment cap, it may be composed of a single drive motor 10 and the drive gear 40.

The overload blocking device of the drive motor 10 is a load geared to the drive gear 40 (here focusing adjustment cap or zoom adjustment cap) is completely moved to one side or the rotation of the drive gear 40 is not made by abnormal operation. It is to prevent the over-current flows into the drive motor 10 when not being damaged, it is to block the power transmission between the drive motor 10 and the drive gear (40).

That is, in normal operation of the present invention, the roller 24 of the protrusion 22 and the roller 46 of the horizontal bar 44 are installed at one end of the driving shaft 20 to which the driving force of the driving motor 10 is transmitted and rotated. The driving force is transmitted to the driving gear 40 by the locking role of the driving gear 40 to rotate.

However, when the rotation of the driving gear 40 is restricted or stopped due to other causes, the interference force is gradually increased between the protrusion 22 and the vertical bar 42 or the horizontal bar 44. Torsional deformation or transverse deformation occurs in the bar. In addition, when the load of the driving motor 10 gradually increases, an overcurrent is applied to the driving motor 10, and when such an overload state reaches a predetermined threshold or more, the vertical bar 42 or the horizontal bar 44 The elastic deformation is maximized and the position of the roller 46 is moved in one direction to operate the switching means to cut off the power applied to the driving motor 10.

On the other hand, the roller 24, 46 is to facilitate the action between the projection 22 and the horizontal bar 44.

Therefore, according to the present invention, since the drive shaft and the arm, which are cut off by the switching means, are no longer rotated, impact noise can be suppressed and product life can be extended.

Claims (4)

A drive motor, a drive shaft connected in a straight line with the motor shaft of the drive motor, and having a protrusion formed radially around the drive motor, a drive gear rotatably installed on the drive shaft, and installed on the side of the drive gear. In the overload blocking device of the projector projection lens driving motor having an "┐" shaped elastic member that interferes with the projection that rotates together with the drive shaft, the elastic deformation in the direction perpendicular to the axial direction, the projection and the elastic member And a switching means for switching the power supply of the drive motor by the pressing of the elastic member at a position where the interference force of the projection is increased so that the protrusion part overcomes the elastic member in which the protrusion is elastically deformed. The overload blocking device of the projector projection lens driving motor of claim 1, wherein the elastic member includes a vertical bar and a horizontal bar, and one of the elastic members has an elastic function in a direction perpendicular to the driving shaft by interference with the protrusion. The overload blocking device of the projector projection lens driving motor according to claim 1, wherein a roller is provided at the tip of the projection to be rotatable in a direction parallel to a rotational direction of the drive shaft. The overload blocking device of a projector projection lens driving motor according to claim 1, wherein the switching means is symmetrically installed at both ends of the horizontal bar.