Patent Description:
A surveillance camera supporting pan/tilt/zoom functions may transmit driving power generated from a stepping motor to an output shaft. In order to transmit such a driving power, a timing belt is normally used to couple a motor shaft of the stepping motor and the output shaft.

By using the timing belt as a power transmission structure, a user can easily adjust a gear ratio and an axial distance. However, in terms of the power transmission, there is an important requirement that the tension of the timing belt should be maintained in an optimal state. In case that the tension of the timing belt is too low, there might be problems of shaking of a camera and slip or malfunctioning of a motor. On the contrary, in a case where the tension of the timing belt is too high, there might be problems of wear-out or damages of components in the camera assembly and a power reduction of the motor due to a load increase.

In this regard, there might be two schemes to solve the problem. The first scheme is to maintain the tension of the timing belt within a designed range by strict quality controls on dimensions and clearances of the related components. In addition, the second scheme is to adjust the tension of the timing belt by manual controls on the axial distance during the assembling process.

Specifically, in a camera driving device that provides a high gear transmission ratio (reduction ratio) and a large torque compared to a power source using a plurality of timing belts, it is not realistic to rely on accuracy of design and assembling tolerances in order to maintain/adjust tensions acting on the timing belts in an appropriate range. That is, when even one of the plurality of timing belts does not have an appropriate tension, problems of power loss and power transfer accuracy occur.

Furthermore, even though design and assembling are accurately made, when decentering or eccentricity occurs in components due to an influence of an installation angle of a camera assembly or an environment, it will be inevitable that a tension of the timing belt deviates from a design value.

<CIT> relates to the technical field of pipe gallery monitoring, in particular to a pipeline monitoring rail type mobile pipeline robot with a simple structure comprising a camera on the pan/tilt mechanism that can automatically scan the monitoring area. <CIT> discloses a lens-barrel rotational drive mechanism for rotating a lens-barrel to which the lens for imaging is attached in a horizontal or the orthogonal/vertical direction, and a lens-barrel rotation type imaging device. <CIT> relates to devices for varying tension in belts of a device according to operation of the device. <CIT> concerns a railway for an overhead camera surveillance system comprising a track, the track being configured to define at least one rail along which at least one motorized camera carriage suspended therefrom is moveable.

Aspects of the present disclosure provide a camera driving device which provides a high gear transmission ratio by a plurality of timing belts and in which tensions acting on the timing belts are automatically adjusted despite parameter deviation of related components, without using a separate assembling facility. In particular, the present disclosure provides a camera driving device of appended claim <NUM> and a method of assembling a camera driving device according to the present disclosure of appended claim <NUM>.

Aspects of the present disclosure also provide a camera driving device which provides a high gear transmission ratio by a plurality of timing belts and in which constant tensions act on the timing belts even when decentering of components occurs or after the components are assembled/disassembled.

The assembling of the gear support on the gear tensioner may include assembling a second mover and a second base that constitute the gear tensioner; mounting the gear support on the second mover; and connecting the second mover and the second base to each other by a second elastic member, and the assembling of the motor on the motor tensioner may include assembling a first mover and a first base that constitute the motor tensioner; mounting the motor on the first mover; and connecting the first mover and the first base to each other by a first elastic member.

According to embodiments, a camera driving device is provided. The camera device includes: a motor configured to generate a driving force; an input pulley attached to the motor; a gear assembly including a first gear coupled to the input pulley by a first timing belt, and a second gear formed coaxially with the first gear, the second gear configured to rotate together with the first gear; and an output pulley configured to rotate together with the second gear by a second timing belt, and mounted with a camera module. A first reduction may be made according to a gear transmission ratio between the input pulley and the first gear, and a second reduction may be made according to a gear transmission ratio between the second gear and the output pulley. A rotation shaft of the output pulley is positioned between a rotation shaft of the input pulley and a rotation shaft of the first gear.

According to one or more embodiments, the camera device further includes a motor tensioner supporting the rotation shaft of the input pulley by elasticity so that the motor is movable; and a gear tensioner supporting the rotation shaft of the first gear and a rotation shaft of the second gear by elasticity so that the gear assembly is movable, wherein a tension of the first timing belt is adjusted by movement of the input pulley and movement of the first gear, and a tension of the second timing belt is adjusted by the movement of the first gear.

According to one or more embodiments, the motor tensioner includes a first base fixed to a camera housing and a first mover that is configured to pivot within a first movable range around a first reference shaft on the first base, and the motor is mounted on the first mover, and the gear tensioner includes a second base fixed to the camera housing, and a second mover that is configured to pivot within a second movable range around a second reference shaft on the second base, and a gear support rotatably supporting the gear assembly is mounted on the second mover.

According to one or more embodiments, the first base includes at least one first slot, the first mover includes at least one first movable shaft accommodated in the at least one first slot so as to be configured to pivot within the first movable range around the first reference shaft, the second base includes at least one second slot, and the second mover includes at least one second movable shaft accommodated in the at least one second slot so as to be configured to pivot within the second movable range around the second reference shaft.

According to one or more embodiments, the first base is in surface contact with the first mover and the second base is in surface contact with the second mover, the first base includes through holes in which at least portions of first fasteners mounting the motor on the first mover are accommodated, in order to avoid interference with the first fasteners, and the second base includes through holes in which at least portions of second fasteners mounting the gear support on the second mover are accommodated, in order to avoid interference with the second fasteners.

According to one or more embodiments, the motor tensioner further includes a first elastic member connected between one side of the first mover and one side of the first base such as to provide a spring force when the first mover pivots on the first base, and the gear tensioner further includes a second elastic member connected between one side of the second mover and one side of the second base such as to provide a spring force when the second mover pivots on the second base.

According to one or more embodiments, the spring force of the second elastic member is greater than the spring force of the first elastic member.

According to one or more embodiments, the second elastic member is a plurality of springs and the first elastic member is a single spring, and wherein the first movable range is greater than the second movable range.

According to the claimed invention, the output pulley is rotatably supported by a pulley support provided in a camera housing, and includes an extension rod extending from the output pulley and coupled to the camera module, and the extension rod penetrates through an inside of the first timing belt.

According to the claimed invention, the first timing belt and the second timing belt are disposed in parallel with each other, and the first timing belt is positioned closer than the second timing belt to the camera module.

According to embodiments, a camera driving device is provided. The camera driving device includes: a motor configured to generate a driving force; an input pulley attached to the motor; a motor tensioner supporting a rotation shaft of the input pulley by elasticity so that the motor is movable; a gear assembly including a first gear coupled to the input pulley by a first timing belt, and a second gear formed coaxially with the first gear, the second gear configured to rotate together with the first gear; a gear tensioner supporting a rotation shaft of the first gear and a rotation shaft of the second gear by elasticity so that the gear assembly is movable; and an output pulley configured to rotate together with the second gear by a second timing belt and mounted with a camera module, wherein a first reduction is made according to a gear transmission ratio between the input pulley and the first gear, a second reduction is made according to a gear transmission ratio between the second gear and the output pulley, a tension of the first timing belt is adjusted by movement of the input pulley and movement of the first gear, and a tension of the second timing belt is adjusted by the movement of the first gear.

According to one or more embodiments, the motor tensioner includes a first base fixed to a camera housing, and a first mover configured to pivot within a first movable range around a first reference shaft on the first base, and the motor is mounted on the first mover, and the gear tensioner includes a second base fixed to the camera housing, and a second mover configured to pivot within a second movable range around a second reference shaft on the second base, and a gear support rotatably supporting the gear assembly is mounted on the second mover.

According to one or more embodiments, the spring force of the second elastic member is greater than the spring force of the first elastic member, the second elastic member is a plurality of springs, and the first elastic member is a single spring.

According to one or more embodiments, the first movable range is greater than the second movable range.

According to one or more embodiments, the output pulley is rotatably supported by a pulley support provided in a camera housing, and includes an extension rod extending from the output pulley and coupled to the camera module, and the extension rod penetrates through an inside of the first timing belt.

According to one or more embodiments, the first timing belt and the second timing belt are disposed in parallel with each other, and the first timing belt is positioned closer than the second timing belt to the camera module.

According to embodiments, a method of assembling a camera driving device according to one or more embodiments is provided. In particular, the camera driving device may include: a motor configured to generate a driving force; an input pulley attached to the motor; a motor tensioner supporting a rotation shaft of the input pulley by elasticity so that the motor is movable; a gear assembly including a first gear coupled to the input pulley by a first timing belt and a second gear formed coaxially with the first gear and configured to rotate together with the first gear; a gear tensioner supporting a rotation shaft of the first gear and a rotation shaft of the second gear by elasticity so that the gear assembly is movable; and an output pulley configured to rotate together with the second gear by a second timing belt and mounted with a camera module. The method includes: installing the output pulley on a pulley support in a camera housing; assembling a gear support on the gear tensioner, the gear support rotatably supporting the gear assembly; coupling the output pulley and the second gear to each other by the second timing belt; assembling the motor on the motor tensioner; and coupling the input pulley, attached to the motor, and the first gear to each other by the first timing belt.

According to one or more embodiments, the assembling the gear support on the gear tensioner includes: assembling a second mover and a second base that constitute the gear tensioner; mounting the gear support on the second mover; and connecting the second mover and the second base to each other by a second elastic member. The assembling the motor on the motor tensioner includes : assembling a first mover and a first base that constitute the motor tensioner; mounting the motor on the first mover; and connecting the first mover and the first base to each other by a first elastic member.

With the camera driving device according to an embodiment of the present disclosure, tensions acting on timing belts may be automatically adjusted without using a separate assembling facility despite data dispersion of related components, and constant tensions may be maintained in the respective timing belts even when decentering of components occurs or after the components are assembled/disassembled.

In addition, with the camera driving device according to an embodiment of the present disclosure, appropriate tensions may be provided to respective timing belts irrespective of the assembling order of a plurality of timing belts.

All embodiments described in this specification may be advantageously combined with one another to the extent that their respective features are compatible. In particular, the expressions "according to an embodiment", "in an embodiment", "an embodiment of the invention provides" etc. mean that the respective features may or may not be part of specific embodiments of the present invention.

The above and other aspects and features of the present disclosure will become more apparent by describing in detail non-limiting example embodiments thereof with reference to the attached drawings, in which:.

Advantages and features of embodiments of the disclosure and methods to achieve them will become apparent from the below descriptions of non-limiting example embodiments with reference to the accompanying drawings. However, embodiments of the disclosure are not limited to the embodiments described below and may be implemented in various ways. The non-limiting example embodiments are provided for making the disclosure thorough and for fully conveying the scope of the disclosure to those skilled in the art. Like reference numerals denote like elements throughout the descriptions.

It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present application, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Terms used herein are for illustrating embodiments rather than limiting the present disclosure. As used herein, the singular forms are intended to include plural forms as well, unless the context clearly indicates otherwise. Throughout this specification, the word "comprise" and variations such as "comprises" or "comprising," will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

Hereinafter, non-limiting example embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

In general, there is a limit in increasing a gear transmission ratio or a reduction ratio using a single timing belt in a camera driving device. First, in order to increase the gear transmission ratio, a gear size may be increased, and accordingly, a size of a required internal space is increased in proportion to the gear size. Second, a contact area of the timing belt connected to a motor shaft is decreased due to such an increase in the gear transmission ratio, such that power transmission force is decreased. Third, in order to solve these problems, an inter-shaft distance may be increased, which causes an additional size problem. Fourth, motor power loss is increased due to an increase in a moment of inertia caused by the increase in the gear size.

In order to provide a high gear transmission ratio while solving these problems, a camera driving device according to an embodiment of the present disclosure utilizes a multi-belt structure. <FIG> is a conceptual diagram of a multi-belt structure used in a camera driving device according to the present disclosure.

According to such a multi-belt structure, there may be a total of three rotation shafts. An input pulley <NUM> connected to an output shaft of a motor forms a first rotation shaft Ax, a gear assembly <NUM> including a first gear <NUM> and a second gear <NUM> forms a second rotation shaft Bx, and finally, an output pulley <NUM> connected to a camera module forms a third rotation shaft Cx.

When the input pulley <NUM> rotates by power generated from the motor, a torque of the input pulley <NUM> is transmitted to the first gear <NUM> through a first timing belt <NUM>. In this case, the second gear <NUM> is coaxial with the first gear <NUM>, and rotates integrally with the first gear <NUM> so as to have the same revolutions per minute (RPM) as the first gear <NUM>. A torque of the second gear <NUM> is finally transmitted to the output pulley <NUM> through a second timing belt <NUM>. In this case, a torque of the output pulley <NUM> follows Equations <NUM> and <NUM> below. <MAT> <MAT>.

In the equations, Gear Transmission Ratio <NUM> is a gear transmission ratio between the input pulley <NUM> and the first gear <NUM> coupled to each other by the first timing belt <NUM>, and Gear Transmission Ratio <NUM> is a gear transmission ratio between the second gear <NUM> and the output pulley <NUM> coupled to each other by the second timing belt <NUM>. Accordingly, a first reduction is made according to the gear transmission ratio between the input pulley <NUM> and the first gear <NUM> (Gear Transmission Ratio <NUM>), and a second reduction is made according to the gear transmission ratio between the second gear <NUM> and the output pulley <NUM> (Gear Transmission Ratio <NUM>). Due to such a high total gear transmission ratio or reduction ratio, it is possible to provide a large output with a small power of the motor.

<FIG> is a perspective view illustrating a camera driving device <NUM> according to an example embodiment of the present disclosure. <FIG> is a plan view illustrating the camera driving device <NUM> of <FIG>. Hereinafter, for convenience of explanation, a cover and a camera module are not illustrated.

The camera driving device <NUM> may generally include a motor <NUM> generating a driving force; an input pulley <NUM> formed on the motor <NUM>; a gear assembly <NUM> including a first gear <NUM> coupled to the input pulley <NUM> by a first timing belt <NUM> and a second gear <NUM> formed coaxially with the first gear <NUM> and rotating together with the first gear <NUM>; and an output pulley <NUM> rotating together with the second gear <NUM> by a second timing belt <NUM> and mounted with a camera module (not illustrated). In this case, a first reduction is made according to a gear transmission ratio between the input pulley <NUM> and the first gear <NUM>, and a second reduction is made according to a gear transmission ratio between the second gear <NUM> and the output pulley <NUM>.

In addition, unlike the conceptual diagram in <FIG>, a third rotation shaft Cx of the output pulley <NUM> is positioned between a first rotation shaft Ax of the input pulley <NUM> and a second rotation shaft Bx of the first gear <NUM>. Through such a modified positioning, a more compact configuration of components of the camera driving device together with a decrease in an overall length of the camera driving device is enabled.

Referring to <FIG> again, the output pulley <NUM> is rotatably supported by a pulley support <NUM> provided in a camera housing <NUM>, and includes an extension rod <NUM> extending from the output pulley <NUM> and coupled to the camera module. The extension rod <NUM> may be disposed to penetrate through the inside of the first timing belt <NUM> for space efficiency of the camera driving device <NUM>.

In addition, the first timing belt <NUM> and the second timing belt <NUM> are disposed in parallel with each other on the upper side and the lower side, respectively, in the camera housing <NUM>, and the first timing belt <NUM> is positioned on the side closer to the camera module than the second timing belt <NUM> is, that is, the upper side of the camera housing <NUM>.

In addition, the camera driving device <NUM> may further include a motor tensioner <NUM> and a gear tensioner <NUM>. The motor tensioner <NUM> supports the rotation shaft of the input pulley <NUM> by elasticity so that the motor <NUM> is movable, and the gear tensioner <NUM> supports the rotation shaft of the first gear <NUM> and a rotation shaft of the second gear <NUM> by elasticity so that the gear assembly <NUM> is movable. According to the camera driving device <NUM> including the motor tensioner <NUM> and the gear tensioner <NUM>, a tension of the first timing belt <NUM> is adjusted by the movement of the input pulley <NUM> and the first gear <NUM>, and a tension of the second timing belt <NUM> is adjusted by the movement of the first gear <NUM>.

Detailed configurations and functions of such a motor tensioner <NUM> and gear tensioner <NUM> will be described later in more detail with reference to the following drawings.

Meanwhile, in order to detect a rotation angle or a rotation speed of the output pulley <NUM> for posture control and measurement of the camera module, the camera driving device <NUM> may further include a rotation detection sensor <NUM> for detecting the rotation angle or the rotation speed of the output pulley <NUM>. For example, N poles and S poles of a plurality of magnets may be alternately disposed in the output pulley <NUM>, and the rotation detection sensor <NUM> may detect the rotation angle of the output pulley <NUM> by counting the number of N poles or S poles detected according to the rotation of the output pulley <NUM>.

<FIG> is an exploded perspective view illustrating a structure in which the motor tensioner <NUM> and the gear tensioner <NUM> are mounted on the camera housing <NUM>. The output pulley <NUM> is rotatably supported by the pulley support <NUM> provided in the camera housing <NUM>. In addition, the motor tensioner <NUM> may be fixedly mounted on first mounts <NUM> formed in the camera housing <NUM> through fasteners, and similarly, the gear tensioner <NUM> may be fixedly mounted on second mounts <NUM> formed in the camera housing <NUM> through fasteners.

<FIG> is a perspective view illustrating a structure in which the motor tensioner <NUM> and the motor <NUM> are assembled. <FIG> is an exploded perspective view of the structure of <FIG>.

Referring to the figures, the motor tensioner <NUM> includes a first base <NUM> fixed to the camera housing <NUM> and a first mover <NUM> pivoting within a first movable range around a first reference shaft <NUM>-<NUM> on the first base <NUM>. In this case, the motor <NUM> is mounted on the first mover <NUM>.

The first base <NUM> includes a plurality of first slots <NUM>-<NUM>, and the first mover <NUM> includes a plurality of first movable shafts <NUM>-<NUM> accommodated, respectively, in the first slots <NUM>-<NUM> so as to pivot within the first movable range around the first reference shaft <NUM>-<NUM>.

Here, the first base <NUM> and the first mover <NUM> are in surface contact with each other, and the first base <NUM> includes through holes <NUM>-<NUM> in which at least portions of fasteners <NUM>-<NUM> mounting the motor <NUM> on the first mover <NUM> are accommodated, in order to avoid interference with the fasteners <NUM>-<NUM>. In addition, the first base <NUM> includes a central opening <NUM>-<NUM> so that the input pulley <NUM> coupled to the first timing belt <NUM> may be exposed to the upper side.

Meanwhile, the motor tensioner <NUM> may further include a first elastic member <NUM> connected between one side of the first mover <NUM> and one side of the first base <NUM> in order to provide a spring force (resilient bias) or a restoring force when the first mover <NUM> pivots on the first base <NUM>. Such a first elastic member <NUM> may be implemented in the form of a coil spring.

<FIG> are views illustrating various positions to which the motor <NUM> may move on the motor tensioner <NUM>. Among <FIG>. <FIG> illustrates a state in which the first mover <NUM> moves the most to the right in a movable range (first movable range) because a belt tension is greater than a spring force of the first elastic member <NUM>. In addition, <FIG> illustrates a state in which the first mover <NUM> moves the most to the left in the movable range because the belt tension is smaller than the spring force. In addition, <FIG> illustrates a state in which the first mover <NUM> is positioned at an intermediate point in the movable range because the belt tension and the spring force are balanced.

In this manner, while the force generated by the first elastic member <NUM> mounted between the first base <NUM> and the first mover <NUM> and the tension of the first timing belt <NUM> are balanced, an appropriate tension may be maintained in the first timing belt <NUM>. When the tension of the first timing belt <NUM> increases or decreases for any reason, the motor <NUM> moves close to or away from the gear assembly <NUM> by the first mover <NUM>. That is, an inter-shaft distance between the rotation shaft Ax of the input pulley <NUM> and the rotation shaft Bx of the gear assembly <NUM> is adaptively adjusted, such that the tension of the first timing belt <NUM> is maintained within an appropriate range.

<FIG> is a perspective view illustrating a structure in which the gear tensioner <NUM> and the gear assembly <NUM> are assembled. <FIG> is an exploded perspective view of the structure of <FIG>.

The gear tensioner <NUM> includes a second base <NUM> fixed to the camera housing <NUM> and a second mover <NUM> pivoting within a second movable range around a second reference shaft <NUM>-<NUM> on the second base <NUM>. In this case, a gear support <NUM> rotatably supporting the gear assembly <NUM> is mounted on the second mover <NUM>.

The second mover <NUM> includes at least one second slot <NUM>-<NUM>, and the second base <NUM> includes at least one second movable shaft <NUM>-<NUM> accommodated in the at least one second slot <NUM>-<NUM> so as to pivot within the second movable range around the second reference shaft <NUM>-<NUM>.

Here, the second base <NUM> and the second mover <NUM> are in surface contact with each other, and the second base <NUM> includes through holes <NUM>-<NUM> in which at least portions of fasteners <NUM>-<NUM> mounting the gear support <NUM> on the second mover <NUM> are accommodated, in order to avoid interference with the fasteners <NUM>-<NUM>. In addition, the second base <NUM> includes a central opening <NUM>-<NUM> so that the second gear <NUM> coupled to the second timing belt <NUM> may be exposed to the lower side.

Meanwhile, the gear tensioner <NUM> may further include a second elastic member <NUM> connected between one side of the second mover <NUM> and one side of the second base <NUM> in order to provide a spring force (resilient bias) or a restoring force when the second mover <NUM> pivots on the second base <NUM>. Such a second elastic member <NUM> may be implemented in the form of a coil spring(s).

<FIG> are views illustrating various positions to which the gear assembly <NUM> may move on the gear tensioner <NUM>.

Among <FIG>, <FIG> illustrates a state in which the second mover <NUM> moves the most to the left in a movable range (second movable range) because a belt tension is greater than a spring force of the second elastic member <NUM>. In addition, <FIG> illustrates a state in which the second mover <NUM> moves the most to the right in the movable range because the belt tension is smaller than the spring force. In addition, <FIG> illustrates a state in which the second mover <NUM> is positioned at an intermediate point in the movable range because the belt tension and the spring force are balanced.

In this manner, while the force generated by the elastic member <NUM> mounted between the second base <NUM> and the second mover <NUM> and the tension of the first timing belt <NUM> and the second timing belt <NUM> are balanced, an appropriate tension may be maintained also in the second timing belt <NUM>. When the tension of the second timing belt <NUM> increases or decreases for any reason, the gear assembly <NUM> moves close to or away from the output pulley <NUM> by the second mover <NUM>. That is, an inter-shaft distance between the rotation shaft Cx of the output pulley <NUM> and the rotation shaft Bx of the gear assembly <NUM> is adaptively adjusted, such that the tension of the second timing belt <NUM> is maintained within an appropriate range.

<FIG> is a plan view illustrating only the input pulley <NUM>, the output pulley <NUM>, the first gear <NUM>, and the second gear <NUM> in the camera driving device <NUM> in order to show a balance between forces generated by the first timing belt <NUM> and the second timing belt <NUM> and the first elastic member <NUM> and the second elastic member <NUM>.

A fluctuation amount of an inter-shaft distance D2 between the second rotation shaft Bx and the third rotation shaft Cx by the gear tensioner <NUM> affects an inter-shaft distance D1 between the first rotation shaft Ax and the second rotation shaft Bx by the motor tensioner <NUM>. Accordingly, the fluctuation amount of the inter-shaft distance D2 should be smaller than a fluctuation amount of the inter-shaft distance D1, and thus, movable ranges of the motor tensioner <NUM> and the gear tensioner <NUM> may be set to be different from each other so that a difference occurs between the fluctuation amounts of the inter-shaft distance D1 and the inter-shaft distance D2 even though the same elastic member is applied to the motor tensioner <NUM> and the gear tensioner <NUM>. That is, the movable range (first movable range) of the first mover <NUM> provided in the motor tensioner <NUM> may be designed to be greater than the movable range (second movable range) of the second mover <NUM> provided in the gear tensioner <NUM>.

In addition, a tension T2 acting on the second timing belt <NUM> is compositely affected by a tension T1 acting on the first timing belt <NUM> and a spring force of the second elastic member <NUM>. Accordingly, a spring force F2 of the second elastic member <NUM> of the gear tensioner <NUM> may be designed to be greater than a spring force F1 of the first elastic member <NUM> of the motor tensioner <NUM>.

Referring to <FIG>, relationships as represented by the following Equation <NUM> and <NUM> are satisfied between the spring force F1 of the first elastic member <NUM>, the spring force F2 of the second elastic member <NUM>, the tension T1 of the first timing belt <NUM>, and the tension T2 of the second timing belt <NUM>. <MAT> <MAT>.

In the equations, α and β are an angle formed by the first timing belt <NUM> and an angle formed by the second timing belt <NUM>, respectively, and T1 and T2 are a tension of the first timing belt <NUM> and a tension of the second timing belt <NUM>, respectively.

<FIG> is a perspective view illustrating an installation form of the first elastic member <NUM> of the motor tensioner <NUM> and the second elastic member <NUM> of the gear tensioner <NUM>.

According to Equations <NUM> and <NUM> described above, the spring force F1 of the second elastic member <NUM> may be greater than the spring force F2 of the first elastic member <NUM>. Specifically, the spring force F1 is calculated to be approximately <NUM> times the spring force F2. In consideration of such a situation, according to an example embodiment of the present disclosure, the second elastic member <NUM> may include two identical coil springs for the gear tensioner <NUM>, and the first elastic member <NUM> may include a single coil spring that is identical to each of the coils springs of the second elastic member <NUM> for the motor tensioner <NUM>.

In addition, there are methods such as a method of adjusting the numbers of turns of the coil springs and a method of adjusting outer diameters of the coil springs, but since it is difficult for an operator to identify the coil springs when looking at only appearances of the coil springs, there may be a possibility of erroneous assembling when assembling the camera driving device <NUM>. However, by adjusting only the numbers of employed identical coil springs as in the above example embodiment, there is an advantage that a risk of erroneous assembling may be decreased and it may be easily confirmed with the naked eyes whether or not assembling abnormality occurs.

Hereinafter, an assembling method of assembling the camera driving device <NUM> described above will be described, for example, with reference to <FIG> and <FIG>.

First, the output pulley <NUM> is installed on the pulley support <NUM> in the camera housing <NUM>. Thereafter, the gear support <NUM> rotatably supporting the gear assembly <NUM> is assembled on the gear tensioner <NUM>. Then, the output pulley <NUM> and the second gear <NUM> are coupled to each other by the second timing belt <NUM>. Then, the motor <NUM> is assembled on the motor tensioner <NUM>. Finally, the input pulley <NUM> formed on the motor <NUM> and the first gear <NUM> are coupled to each other by the first timing belt <NUM>, such that the assembling of the camera driving device <NUM> is completed. The reason for installing the first timing belt <NUM> after installing the second timing belt <NUM> as described above is to decrease an assembling error of the first timing belt <NUM> and the second timing belt <NUM> because the tension of the second timing belt <NUM> affects the first timing belt <NUM>. However, in the camera driving device <NUM> according to the present disclosure, the inter-shaft distance D1 and the inter-shaft distance D2 (see <FIG>) are automatically adjusted even after the installation of the first timing belt <NUM> and the second timing belt <NUM>, and thus, a particular problem may not occur even though the installation order described above is changed.

In the assembling method described above, a process of assembling the gear support <NUM> on the gear tensioner <NUM> may be performed more specifically in the order of a step of assembling the second mover <NUM> and the second base <NUM> that constitute the gear tensioner <NUM>, a step of mounting the gear support <NUM> on the second mover <NUM>, and a step of connecting the second mover <NUM> and the second base <NUM> to each other by the second elastic member <NUM>.

Similarly, a process of assembling the motor <NUM> on the motor tensioner <NUM> may be performed in the order of a step of assembling the first mover <NUM> and the first base <NUM> that constitute the motor tensioner <NUM>, a step of mounting the motor <NUM> on the first mover <NUM>, and a step of connecting the first mover <NUM> and the first base <NUM> to each other by the first elastic member <NUM>.

Claim 1:
A camera driving device (<NUM>) comprising:
a motor (<NUM>) configured to generate a driving force;
an input pulley (<NUM>) attached to the motor (<NUM>);
a gear assembly (<NUM>) including a first gear (<NUM>) coupled to the input pulley (<NUM>) by a first timing belt (<NUM>), and a second gear (<NUM>) formed coaxially with the first gear (<NUM>), the second gear (<NUM>) configured to rotate together with the first gear (<NUM>); and
an output pulley (<NUM>) configured to rotate together with the second gear (<NUM>) by a second timing belt (<NUM>), and mounted with a camera module,
wherein a rotation shaft (Cx) of the output pulley (<NUM>) is positioned between a rotation shaft (Ax) of the input pulley (<NUM>) and a rotation shaft (Bx) of the first gear (<NUM>),
wherein the output pulley (<NUM>) is rotatably supported by a pulley support (<NUM>) provided in a camera housing (<NUM>), and comprises an extension rod (<NUM>) extending from the output pulley (<NUM>) and coupled to the camera module, and the extension rod (<NUM>) penetrates through an inside of the first timing belt (<NUM>), and
wherein the first timing belt (<NUM>) and the second timing belt (<NUM>) are disposed in parallel with each other, and the first timing belt (<NUM>) is positioned closer than the second timing belt (<NUM>) to the camera module.