Patent Description:
A cellular communication system is used to provide wireless communication to fixed and mobile users. The cellular communication system may include a plurality of base stations, and each base station provides a wireless cellular service for a designated coverage area (generally referred to as a "cell"). Each base station may include one or more base station antennas, and the base station antenna is used to transmit radio frequency ("RF") signals to a user located in a cell served by the base station and receive RF signals from the user. The base station antenna is a directional device that can concentrate RF energy transmitted in certain directions or received from certain directions.

A modern base station antenna usually includes two, three or more linear (or planar) arrays of radiating elements, where each linear array has an electronically adjustable downtilt angle. The linear array usually includes a cross-polarized radiating element, and is provided with a separate phase shifter for electronically adjusting the downtilt angle of antenna beams for each polarization, so that the antenna can include twice the phase shifters of the linear array. In addition, in many antennas, a separate transmitting and receiving phase shifter is provided so that transmitting and receiving radiation patterns can be adjusted independently. This would again double the number of phase shifters. Therefore, it is not surprising that the base station antenna has eight, twelve, eighteen, thirty-two, or more phase shifters for applying remote electrical downtilt angles to linear arrays.

A remote electrical tilt ("RET") actuator and an associated transmission mechanism may be provided in the base station antenna to adjust the phase shifter. Conventionally, each phase shifter is equipped with a separate RET actuator, which results in the base station antenna including a large number of RET actuators, thereby significantly increasing the size, weight, and cost of the base station antenna. Therefore, in some cases, it is necessary to use a RET actuator including a single motor to simultaneously drive a plurality of phase shifters.

<FIG> shows a transmission mechanism <NUM> of the prior art, which attempts to use a single motor <NUM> to drive a plurality of shifters <NUM>. The transmission mechanism <NUM> includes a driving rod <NUM> driven by the motor <NUM> via a screw <NUM> and a plurality of connecting rods <NUM> parallel to the driving rod <NUM> and spaced apart from each other in a transverse direction perpendicular to an axial direction of the driving rod <NUM>. Each connecting rod <NUM> can drive one or more phase shifters to adjust downtilt angles thereof. A plurality of connecting rods <NUM> are fixed together via one or more connecting plates <NUM> to simultaneously move axially when driven by the driving rod <NUM>, thereby driving a plurality of phase shifters.

Limited by the output power of the motor <NUM>, the transmission mechanism <NUM> of the prior art can only drive a limited number of phase shifters. For example, currently a motor usually used in a base station antenna can generate a pulling force of about <NUM> lbf, while a pulling force of about <NUM> lbf is needed to drive a phase shifter. Therefore, a motor can only drive up to <NUM> phase shifters. However, in some cases, it is required that a single motor be used to drive at least <NUM> phase shifters, and the transmission mechanism <NUM> obviously cannot meet such requirement.

Moreover, since the plurality of connecting rods <NUM> are spaced apart from each other in the transverse direction, each connecting rod <NUM> has a moment arm as compared with the driving rod <NUM>, and has torque as a result. Since each connecting rod <NUM> has a different moment arm size compared with the driving rod <NUM>, the generated torque is also different, which will cause the plurality of connecting rods <NUM> to generate uneven driving forces and therefore affect the adjustment accuracy of the corresponding phase shifters.

Furthermore, as shown in <FIG>, in the prior art, each connecting rod <NUM> drives a movable element <NUM> of each phase shifter via a connecting element <NUM> fixed thereon to make the movable element <NUM> move in an arc-shaped groove <NUM>. When the movable element <NUM> deviates from the central position of the arc-shaped groove <NUM>, a pulling force <NUM> generated by the connecting rod <NUM> will generate a tangential component <NUM> and a radial component <NUM>, of which only the tangential component <NUM> can be used to drive the movable element <NUM>. This reduces the effective pulling force generated by the connecting rod <NUM>, thereby further reducing the number of phase shifters that can be driven by a single motor <NUM>. In addition, when the movable element <NUM> moves to both ends of the arc-shaped groove <NUM>, the movable element <NUM> may be stuck at the end portions of the arc-shaped groove <NUM> and be difficult to move out. Therefore, a larger force is required, which further reduces the number of phase shifters that can be driven by a single motor <NUM>.

Prior art document <CIT> describes base station antennas which include a RET actuator, a plurality of phase shifters and a plurality of mechanical linkages, where each mechanical linkage is connected between the RET actuator and a respective one or more of the phase shifters. The RET actuator includes a drive element, a rotatable element and a mechanical linkage selection system that is configured to move a selected one of the mechanical linkages into engagement with the drive element. The drive element is configured to move linearly in response to rotation of the rotatable element to move the selected one of the mechanical linkages.

<CIT> describes a transmission device for an antenna phase shifter, comprising a transmission input portion, a shift selection portion, and a transmission output portion; the transmission input portion is fully separated from the shift selection portion and selects, by means of the shift selection portion, to establish transmission connection with any output terminal of the transmission output portion, thereby performing phase adjustment on a phase shifter that is connected to the output terminal. In the present invention, two motors are responsible for power input and selection output respectively so as to select to drive any number of phase shifters; furthermore, the structure is compact, and output terminals of the transmission output portion may be spread out flat, being beneficial for antenna layout.

<CIT> discloses that an antenna internal overall rotation of the transmission mechanism includes a worm wheel, worm, drive motor, the worm wheel and antenna reflector plate fixed installation, and the worm wheel rotation axis and the reflector plate rotation axis to, the worm and the worm wheel with the worm wheel meshing with the transmission, the worm rotation axis and worm wheel rotation axis intersection, the drive motor connection and drive worm rotation. The turbine worm gear itself has a self-locking function, so that the whole structure can be self-locking. The transmission mechanism through two-stage conversion can achieve a larger transmission ratio to meet the self-locking needs; and because the worm wheel and worm gear in the first limit structure and the second limit structure contact relative limit, that is, the structure to achieve the mechanical zero demand, through the worm gear and worm gear variant structure to make the search for zero position is simple.

An object of the present invention is to provide a transmission mechanism for a base station antenna and a base station antenna including the transmission mechanism, which can overcome at least one defect in the prior art. This is achieved by the invention according to claim <NUM>. The dependent claims provide further embodiments of this invention.

Multiple aspects of the present invention will be better understood after the following specific embodiments are read with reference to the attached drawings. In the attached drawings:.

It should be understood that in all the attached drawings, the same reference numerals and signs denote the same elements. In the attached drawings, the size of certain features may be changed and are not drawn to scale for clarity.

The present invention will be described below with reference to the attached drawings, and the attached drawings illustrate several embodiments of the present invention. However, it should be understood that the present invention may be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure of the present invention more complete and to fully explain the protection scope of the present invention to those skilled in the art. It should also be understood that the embodiments disclosed in the present invention may be combined in various ways so as to provide more additional embodiments. The invention is defined by the claims in this patent and any contradictory proposals below will, to the skilled reader, be understood as related information not falling under the scope of the invention.

It should be understood that the terms in the specification are only used to describe specific embodiments and are not intended to limit the present invention. Unless otherwise defined, all terms (including technical terms and scientific terms) used in the specification have the meanings commonly understood by those skilled in the art. For brevity and/or clarity, well-known functions or structures may not be described in detail.

The singular forms "a", "an", "the" and "this" used in the specification all include plural forms unless clearly indicated. The words "include", "contain" and "have" used in the specification indicate the presence of the claimed features, but do not exclude the presence of one or more other features. The word "and/or" used in the specification includes any or all combinations of one or more of the related listed items.

In the specification, when it is described that an element is "on" another element, "attached" to another element, "connected" to another element, "coupled" to another element, or "in contact with" another element, etc., the element may be directly on another element, attached to another element, connected to another element, coupled to another element, or in contact with another element, or an intermediate element may be present.

In the specification, the terms "first", "second", "third", etc. are only used for convenience of description and are not intended to be limiting. Any technical features represented by "first", "second", "third", etc. are interchangeable.

In the specification, terms expressing spatial relations such as "upper", "lower", "front", "rear", "top", and "bottom" may describe the relation between one feature and another feature in the attached drawings. It should be understood that, in addition to the orientations shown in the attached drawings, the terms expressing spatial relations further include different orientations of a device in use or operation. For example, when a device in the attached drawings is turned upside down, the features originally described as being "below" other features now can be described as being "above" the other features. The device may also be oriented in other directions (rotated by <NUM> degrees or in other orientations), and in this case, a relative spatial relation will be explained accordingly.

Referring to <FIG>, a transmission mechanism <NUM> for a base station antenna according to an embodiment of the present disclosure is shown. The transmission mechanism <NUM> may include a plurality of connecting rods <NUM> arranged in parallel. The plurality of connecting rods <NUM> may be driven by a single motor <NUM> simultaneously to move axially, and each connecting rod <NUM> may drive a movable element (for example, a brush piece of a rotating brush-type phase shifter) of one or more phase shifters <NUM> when moving axially to adjust a directional angle (for example, an elevation angle or a downtilt angle) of antenna beams generated by the base station antenna. In the embodiments shown in <FIG>, the transmission mechanism <NUM> includes eight connecting rods <NUM> arranged in parallel, and each connecting rod <NUM> can simultaneously drive two pairs of shifters <NUM> spaced apart in the axial direction of the connecting rod <NUM>. Therefore, the transmission mechanism <NUM> can simultaneously drive <NUM> phase shifters. However, the present disclosure is not limited thereto, and the transmission mechanism <NUM> of the present disclosure may be used to drive any other number of phase shifters. In an embodiment of the present disclosure, the connecting rod <NUM> may be made of glass fiber, other plastics, or metal.

The transmission mechanism <NUM> may include a worm gear unit. As shown more clearly in <FIG>, the worm gear unit may include a worm <NUM> extending in the direction of the connecting rod <NUM> and a worm gear <NUM> meshed and connected with the worm <NUM>. The worm <NUM> is configured to be driven by the motor <NUM> to rotate about its longitudinal axis. To this end, one end of the worm <NUM> may be directly or indirectly connected with an output shaft of the motor <NUM>, and the other end of the worm <NUM> may be supported by a supporting element <NUM>. The worm gear <NUM> may be arranged above the worm <NUM> and rotate driven by the worm <NUM>. The central axis of the worm gear <NUM> may be arranged to be perpendicular to the worm <NUM>.

In an embodiment according to the present disclosure, the output torque of the motor <NUM> may be amplified to varying degrees by selecting the gear ratio of the worm gear <NUM> and the worm <NUM> of the worm gear unit, so that a single motor <NUM> can drive a larger number of phase shifters. Generally speaking, the number of heads of the worm <NUM> may be <NUM> to <NUM>, and the number of teeth of the worm gear <NUM> may be several times the number of the heads of the worm <NUM>. In an embodiment according to the present disclosure, the number of heads of the worm <NUM> may be <NUM>, and the number of teeth of the worm gear <NUM> may be <NUM> to <NUM>. Therefore, the gear ratio of the worm gear <NUM> and the worm <NUM> is from <NUM> to <NUM>. In this way, the worm gear unit can amplify the output torque of the motor <NUM> by <NUM> to <NUM> times, so that when the same motor is used for driving, the pulling force generated by the transmission mechanism <NUM> is <NUM> to <NUM> times the pulling force generated by the transmission mechanism <NUM> in the prior art. The gear ratio of the worm gear <NUM> and the worm <NUM> may also be in other appropriate ranges, such as <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and so on.

The worm gear unit can reduce the output rotation speed of the motor <NUM> while amplifying the output torque of the motor <NUM>, and a lower rotation speed makes it possible to adjust the phase shifter more accurately. In addition, comparing with the screw <NUM> used in the prior art, the worm <NUM> of the worm gear unit can have a smaller length, which can reduce the space occupied by the transmission mechanism <NUM> in the base station antenna.

The transmission mechanism <NUM> may further include a plurality of gear pairs, and each gear pair is used to drive a corresponding connecting rod <NUM>. In the embodiments shown in <FIG>, since the transmission mechanism <NUM> includes eight connecting rods <NUM>, it correspondingly includes eight gear pairs. The gear pair is used to further amplify the output torque of the motor <NUM>. As shown more clearly in <FIG> and <FIG>, each gear pair includes a small gear <NUM> and a large gear <NUM> meshed with the small gear <NUM>. All the small gears <NUM> of the plurality of gear pairs and the worm gear <NUM> are mounted on a common drive shaft <NUM> so that the small gears <NUM> rotate synchronously with the worm gear <NUM>. The drive shaft <NUM> extends in a direction perpendicular to the connecting rod <NUM>, and the small gears <NUM> of the plurality of gear pairs are spaced apart from each other on the drive shaft <NUM>. The drive shaft <NUM> can ensure that the small gears <NUM> of the plurality of gear pairs have the same rotation speed, and can evenly transmit the output torque of the worm gear <NUM> to each small gear <NUM> via the drive shaft <NUM>. This can solve the problem that the driving forces of the plurality of connecting rods <NUM> are uneven in the transmission mechanism <NUM> in the prior art, and thus can more accurately adjust a plurality of phase shifters in the base station antenna synchronously.

Similarly, all the large gears <NUM> of the plurality of gear pairs may also be mounted on a common drive shaft <NUM> and be spaced apart from each other. The drive shaft <NUM> makes all the large gears <NUM> of the plurality of gear pairs have the same rotation speed and therefore have a uniform output torque. However, in other embodiments according to the present disclosure, the large gears <NUM> of the plurality of gear pairs may also not be mounted on the common drive shaft <NUM> but are independent of each other.

According to needs, the output torque of the motor <NUM> may be further amplified to varying degrees and the output rotation speed of the motor <NUM> may be reduced at the same by selecting the gear ratio of the large gear <NUM> and the small gear <NUM>. This makes it possible not only to use a single motor <NUM> to drive a larger number of phase shifters at the same time, but also to adjust the phase shifters more accurately at a lower speed.

In an embodiment according to the present disclosure, the drive shaft <NUM> may have a non-circular (for example, rectangular) cross-section, which extends through a non-circular hole provided in the center of the small gear <NUM> for matching with the non-circular cross section of the drive shaft <NUM>, so that the small gear <NUM> is not rotatable relative to the drive shaft <NUM>. Similarly, the drive shaft <NUM> may have a non-circular (for example, rectangular) cross section, which extends through a non-circular hole provided in the center of the large gear <NUM> for matching with the non-circular cross section of the drive shaft <NUM>, so that the large gear <NUM> is not rotatable relative to the drive shaft <NUM>. In another embodiment of the present disclosure, the drive shaft <NUM> may be integrally formed with the small gear <NUM> and the worm gear <NUM>, and the drive shaft <NUM> may be integrally formed with the large gear <NUM>.

In order to enhance the support for the small gear <NUM>, a supporting member <NUM> may be further provided for each small gear of the plurality of gear pairs. <FIG> respectively show the specific structures of the small gear <NUM> and the supporting member <NUM> according to an embodiment of the present disclosure. The small gear <NUM> may include a body having a non-circular hole <NUM>. The body includes a tooth portion <NUM> provided with teeth and a shaft portion <NUM> adapted to be mounted in the supporting member <NUM> to enable the small gear to rotate. Both ends of the shaft portion <NUM> are provided with flanges <NUM> and <NUM>, and the flanges <NUM> and <NUM> restrict the translation of the small gear <NUM> relative to the supporting member <NUM>. The supporting member <NUM> may include a base <NUM>, a body <NUM> extending upright from the base <NUM>, and an annular sleeve <NUM> at the top end of the body <NUM>. The base <NUM> may be fixed in the base station antenna. The shaft portion <NUM> of the small gear <NUM> may be rotatably mounted in the annular sleeve <NUM>, wherein the flanges <NUM> and <NUM> are respectively located on two sides of the annular sleeve <NUM> to restrict the translation of the small gear <NUM> relative to the supporting member <NUM>. The supporting member <NUM> may be configured as a separate structure for ease of the installation of the small gear <NUM>.

Returning to <FIG>, each gear pair of the transmission mechanism <NUM> drives a corresponding connecting rod <NUM> through a rack element <NUM> meshed and connected with the large gear <NUM>. The rack element <NUM> may be fixedly mounted on the connecting rod <NUM>. As a result, when the large gear <NUM> rotates, the large gear <NUM> can axially move the connecting rod <NUM> via the rack element <NUM>, thereby moving the movable element of one or more phase shifters <NUM>. Each large gear <NUM> can drive the corresponding connecting rod <NUM> more stably and efficiently through the rack element <NUM>.

<FIG> shows the specific structure of the rack element <NUM> according to an embodiment of the present disclosure. The rack element <NUM> may include a bottom plate <NUM>, a vertical plate <NUM> extending vertically upward from one side of the bottom plate <NUM>, and a rack <NUM> located at the top end of the vertical plate <NUM>. The rack <NUM> includes a plurality of teeth to be meshed with the large gear <NUM>. The vertical plate <NUM> is provided with a connecting element for connecting with the connecting rod <NUM>. The connecting element may include a series of posts <NUM> and a pair of snap clips <NUM>. The post <NUM> is accommodated in a corresponding cylindrical hole in the corresponding connecting rod <NUM>, and the snap clip <NUM> holds the connecting rod <NUM> in place when the post is inserted into the cylindrical hole of the connecting rod <NUM>, thereby causing the rack element <NUM> to be fixed to the connecting rod <NUM>. However, it should be understood that any one of a variety of connecting elements may be used, for example, a post, a bolt, a hook and a connecting fastener, a groove, etc..

In order to solve the problem that the pulling force <NUM> generated by the connecting rod <NUM> of the transmission mechanism <NUM> in the prior art will generate the tangential component <NUM> and the radial component <NUM> when the movable element <NUM> deviates from the central position of the arc-shaped groove <NUM>, the transmission mechanism <NUM> of the present disclosure further includes an arc-shaped connecting member <NUM> adapted to drive the movable element of the phase shifter to move together along an arc. As shown in <FIG>, the arc-shaped connecting member <NUM> is configured in the form of an arc-shaped rack, and teeth <NUM> are provided on the front end surface of the arc-shaped connecting member <NUM>. The movable element (for example, a brush piece of a rotating brush type phase shifter) of the phase shifter may be fixedly connected with the arc-shaped connecting member <NUM> at the central position of the arc-shaped connecting member <NUM> so as to move driven by the arc-shaped connecting member <NUM>. The teeth of the arc-shaped connecting member <NUM> are meshed with teeth <NUM> of a rack element <NUM> fixed on the connecting rod <NUM>, so that the arc-shaped connecting member <NUM> rotates when the rack element <NUM> moves axially, thereby driving the movable element of the phase shifter to rotate.

Unlike the rack element <NUM>, the rack element <NUM> includes a bottom plate <NUM>. One surface of the bottom plate <NUM> is provided with a rack <NUM> including a plurality of teeth <NUM>, and the opposite surface of the bottom plate <NUM> is provided with a connecting element such as a post and a snap clip to fix the rack element <NUM> on the connecting rod <NUM>. In the embodiments shown in <FIG>, each rack element <NUM> fixed on the connecting rod <NUM> can drive the movable elements of a pair of phase shifters. Therefore, the rack element <NUM> may include two sets of teeth <NUM> arranged in a mirror image, and each set of teeth <NUM> is meshed with the teeth <NUM> of an arc-shaped connecting member <NUM>. Accordingly, the two movable elements in each pair of phase shifters are arranged so that their end portions with which the arc-shaped connecting members <NUM> are connected face each other.

With the help of the arc-shaped connecting member <NUM>, the pulling force of the connecting rod <NUM> is always maintained in the axial direction of the connecting rod <NUM> without component in any other directions. As a result, the pulling force of the connecting rod <NUM> can all be used to move the movable element of the phase shifter without any efficiency loss. In addition, when the arc-shaped connecting member <NUM> is used, the arc-shaped groove <NUM> in the prior art is no longer needed. Therefore, there will not be the problem that the removable element of the phase shifter get stuck in the arc-shaped groove <NUM> and is difficult to move out.

In the embodiments according to the present disclosure, the worm gear <NUM>, the small gear <NUM>, the large gear <NUM>, the rack elements <NUM> and <NUM>, and the arc-shaped connecting member <NUM> may all be made of plastic, and the drive shafts <NUM> and <NUM> may be made of glass fiber. In order to further enhance the torsional strength of the drive shafts <NUM> and <NUM>, the drive shafts <NUM> and <NUM> may also be made of metal or other materials with high torsional strength.

Although the transmission mechanism <NUM> according to the present disclosure includes a plurality of connecting rods <NUM> and a plurality of gear pairs in the embodiments shown in <FIG>, the transmission mechanism <NUM> according to the present disclosure may also include only one connecting rod <NUM> and one gear pair. In this case, the transmission mechanism <NUM> can still amplify the output torque of the motor <NUM> and reduce the output rotation speed of the motor <NUM> through the worm gear unit and the gear pair, thereby still retaining all the aforementioned advantages of the transmission mechanism <NUM>.

Referring to <FIG>, a transmission mechanism <NUM> for a base station antenna according to a claimed embodiment of the present invention is shown. The transmission mechanism <NUM> may include a plurality of connecting rods <NUM> arranged in parallel. The plurality of connecting rods <NUM> may be configured to be driven by a single motor <NUM> to rotate synchronously, and each connecting rod <NUM> may drive a movable element (for example, a brush piece of a rotating brush-type phase shifter) of one or more phase shifters <NUM> when rotating, so as to adjust a directional angle (for example, an elevation angle or a downtilt angle) of antenna beams generated by the base station antenna. Compared with the axially movable connecting rod <NUM> shown in <FIG>, the connecting rod <NUM> is configured to be rotatable instead of axially movable, which not only can significantly shorten the axial length of the transmission mechanism <NUM>, thereby reducing the axial space occupied by the transmission mechanism <NUM>, but also can effectively prevent the connecting rod <NUM> from interfering with other components due to axial movement. In the embodiment shown in <FIG>, the transmission mechanism <NUM> includes eight connecting rods <NUM> arranged in parallel, and each connecting rod <NUM> can drive a pair of phase shifters <NUM>. However, the present invention is not limited thereto, and the transmission mechanism <NUM> may include more connecting rods <NUM> and each connecting rod <NUM> may drive more pairs of phase shifters.

The motor <NUM> may make the plurality of connecting rods <NUM> rotate synchronously through a plurality of gear mechanisms. In the embodiments shown in <FIG>, the motor <NUM> may make the plurality of connecting rods <NUM> rotate synchronously through a gear mechanism <NUM> and a plurality of gear mechanisms <NUM>.

As shown in <FIG>, the gear mechanism <NUM> may include a driving gear 204a and a driven gear 204b. The driving gear 204a may be fixedly mounted at one end of an output shaft (which may extend along an axial direction of the connecting rod <NUM>) of the motor <NUM> and may be driven by the motor <NUM> to rotate. The driven gear 204b is meshed and connected with the driving gear 204a, so that it can be driven by the driving gear 204a to rotate. In an embodiment according to the present invention, the driving gear 204a and the driven gear 204b each may be a helical gear, and the rotation axis of the driving gear 204a and the rotation axis of the driven gear 204b may be configured to be perpendicular to each other. However, the present invention is not limited thereto. The driving gear 204a and the driven gear 204b may have any other suitable configurations.

Similarly, as shown in <FIG>, each gear mechanism <NUM> may include a driving gear 205a and a driven gear 205b. All the driving gears 205a of the plurality of gear mechanisms <NUM> and the driven gear 204b of the gear mechanism <NUM> may be fixedly mounted on a common drive shaft <NUM> while being spaced apart from each other, so that the driving gears 205a of the plurality of gear mechanisms <NUM> can rotate synchronously around the rotation axis of the drive shaft <NUM> driven by the driven gear 204b of the gear mechanism <NUM>. The drive shaft <NUM> may extend in a direction perpendicular to the connecting rod <NUM>. The driven gear 205b of each gear mechanism <NUM> may be fixedly mounted on one end of the corresponding connecting rod <NUM>, and may be meshed and connected with the driving gear 205a of the gear mechanism <NUM>, so as to be able to be driven by the driving gear 205a to rotate and thus drive the corresponding connecting rod <NUM> to rotate. In an embodiment according to the present invention, the driving gear 205a and the driven gear 205b each may be a helical gear, and the rotation axis of the driving gear 205a and the rotation axis of the driven gear 205b may be configured to be perpendicular to each other. However, the present invention is not limited thereto. The driving gear 205a and the driven gear 205b may have any other suitable configurations.

In another embodiment according to the present invention, the transmission mechanism <NUM> may not include the gear mechanism <NUM>. In the embodiment, one end of the output shaft of the motor <NUM> may be provided with only a single driving gear, and the single driving gear may be meshed and connected with the driving gear 205a of any one gear mechanism <NUM> of the plurality of gear mechanisms <NUM>, so as to drive all the driving gears 205a in the plurality of gear mechanisms <NUM> to rotate synchronously via the drive shaft <NUM>, thereby driving the plurality of connecting rods <NUM> to rotate synchronously via the driven gears 205b in the plurality of gear mechanisms <NUM>.

Referring to <FIG>, in order to enable each connecting rod <NUM> to drive the movable elements of one or more phase shifters <NUM> when it rotates, a worm <NUM> is mounted at an end of the connecting rod <NUM> opposite to the end at which the driven gear 205b of the gear mechanism <NUM> is mounted. The worm <NUM> may extend along the axial direction of the connecting rod <NUM> and rotate together with the connecting rod <NUM>. Correspondingly, the transmission mechanism <NUM> further includes an arc-shaped connecting member <NUM> adapted to drive the movable element of the phase shifter <NUM> to move together along an arc. As shown in <FIG>, the arc-shaped connecting member <NUM> may be configured in the form of an arc-shaped rack or a toothed arc-shaped segment, and teeth <NUM> are provided on its front end surface so as to be meshed and connected with the worm <NUM> to form a worm gear unit. A movable element <NUM> (for example, a brush piece of a rotating brush type phase shifter) of the phase shifter may be fixedly connected with the arc-shaped connecting member <NUM> at a side surface of the arc-shaped connecting member <NUM> (see <FIG>) so as to move along an arc driven by the arc-shaped connecting member <NUM> when the worm <NUM> rotates.

As shown in <FIG> and <FIG>, in an embodiment according to the present claimed invention, each worm <NUM> may be meshed with a pair of arc-shaped connecting members <NUM> to simultaneously drive the movable elements of a pair of phase shifters. The pair of arc-shaped connecting members <NUM> may be arranged opposite to each other on both sides of the worm <NUM> and may be substantially in the same horizontal plane as the worm <NUM>. In order to make the pair of arc-shaped connecting members <NUM> rotate opposite to each other driven by the worm <NUM>, the inclined direction of teeth of a first arc-shaped connecting member and the inclined direction of teeth of a second arc-shaped connecting member in the pair of arc-shaped connecting members <NUM> may be opposite to each other.

Unlike the transmission mechanism <NUM> that uses the axial movement of the rack element <NUM> to drive the movable element of the phase shifter, the transmission mechanism <NUM> uses the rotation of the worm <NUM> to drive the movable element of the phase shifter. This method can generate greater driving force, so that a single motor <NUM> can drive more connecting rods <NUM> at the same time. In addition, the transmission mechanism <NUM> does not need to use the rack element <NUM> and the worm <NUM> and the arc-shaped connecting member <NUM> are substantially in the same horizontal plane, so that the height of the entire transmission mechanism <NUM> can be significantly reduced (the height of the transmission mechanism <NUM> is about <NUM>, while the height of the transmission mechanism <NUM> may be only <NUM>). Therefore, the transmission mechanism <NUM> is particularly suitable for <NUM> base station antennas. This is because the <NUM> base station antenna requires the transmission mechanism to occupy a height and a space as smaller as possible so as to make the <NUM> base station antenna thinner and more compact.

In an embodiment according to the present invention, the gear ratio of one or more of the gear mechanism <NUM>, the gear mechanism <NUM>, and the worm gear unit formed by the worm <NUM> and the arc-shaped connecting member <NUM> may be <NUM>:<NUM>. In other embodiments according to the present invention, the output torque of the motor <NUM> may be amplified to varying degrees by changing the gear ratio of one or more of the gear mechanism <NUM>, the gear mechanism <NUM>, and the worm gear unit formed by the worm <NUM> and the arc-shaped connecting member <NUM>, so that a single motor <NUM> can drive a larger number of phase shifters. In addition, amplifying the output torque of the motor <NUM> can also reduce the output rotation speed of the motor <NUM>, so that the transmission mechanism <NUM> can adjust the phase shifter more accurately.

In an embodiment according to the present invention, a supporting member <NUM> shown in <FIG> may be used to support the gear mechanism <NUM>, the gear mechanism <NUM>, and/or the worm <NUM>. The supporting member <NUM> may include a base <NUM> and a ring-shaped body <NUM> on the base <NUM>. The base <NUM> and the ring-shaped body <NUM> may be connected by a reinforcing rib <NUM>. The base <NUM> may be fixed on a corresponding component of the base station antenna. The ring-shaped body <NUM> includes an annular channel <NUM>, and the gears of the gear mechanisms <NUM> and <NUM> (see <FIG> and <FIG>), and/or both ends of the worm <NUM> (see <FIG>) may be accommodated in the annular channel <NUM> and can rotate therein. In an embodiment according to the present invention, the ring-shaped body <NUM> may be configured as a flexible member and may include a cutout <NUM>, so that the annular channel <NUM> of the ring-shaped body <NUM> can expand to facilitate the placement of the gears of the gear mechanisms <NUM> and <NUM> and/or both ends of the worm <NUM>, and can shrink to constrain the gears of the gear mechanisms <NUM> and <NUM> and/or both ends of the worm <NUM> placed therein. A connecting element <NUM> may be used to connect the cutout <NUM>. In other embodiments according to the present invention, the supporting member <NUM> may have a structure similar to the supporting member <NUM>.

In an embodiment according to the present invention, the connecting rod <NUM> and the drive shaft <NUM> may have non-circular cross-sections such as polygonal shapes or special shapes, and the gears of the gear mechanisms <NUM> and <NUM> and the ends of the worm <NUM> may be provided with non-circular matching holes for accommodating the connecting rod <NUM> and the drive shaft <NUM>, so that after being assembled, the gears of the gear mechanisms <NUM> and <NUM> and the worm <NUM> cannot rotate relative to the corresponding connecting rod <NUM> and/or the drive shaft <NUM>.

In the embodiments according to the present invention, the gear mechanisms <NUM> and <NUM>, the worm <NUM>, and the arc-shaped connecting member <NUM> may all be made of plastic. The connecting rod <NUM> and the drive shaft <NUM> may be made of glass fiber. In order to further enhance the torsional strength of the connecting rod <NUM> and the drive shaft <NUM>, the drive shaft <NUM> may also be made of high-strength plastic, metal or other materials with high torsional strength.

Similarly, although the transmission mechanism <NUM> according to the present invention includes a plurality of connecting rods <NUM> and a plurality of gear mechanisms in the embodiment shown in <FIG>, it should be understood that the transmission mechanism <NUM> according to the present invention may include only one connecting rod <NUM> and one gear mechanism while still maintaining the aforementioned advantages.

Claim 1:
A transmission mechanism (<NUM>) for a base station antenna, including a motor (<NUM>) and at least one connecting rod (<NUM>), wherein a gear mechanism (<NUM>) is provided on a first end of the connecting rod (<NUM>), and the motor (<NUM>) drives the connecting rod (<NUM>) to rotate via the gear mechanism (<NUM>);
wherein a worm gear unit (<NUM>) is provided on a second end of the connecting rod (<NUM>) opposite to the first end, and the worm gear unit (<NUM>) is configured to drive a movable element of a phase shifter when the connecting rod (<NUM>) rotates;
wherein the worm gear unit includes a worm (<NUM>) and a toothed arc-shaped connecting member (<NUM>) meshed and connected with the worm (<NUM>), the worm (<NUM>) is mounted on the second end of the connecting rod (<NUM>) and extends along the axial direction of the connecting rod (<NUM>), and the movable element of the phase shifter is fixedly connectable with the arc-shaped connecting member (<NUM>) on a side surface of the arc-shaped connecting member (<NUM>); and
characterized in that the worm gear unit (<NUM>) includes a pair of toothed arc-shaped connecting members (<NUM>), a first toothed arc-shaped connecting member (<NUM>) and a second toothed arc-shaped connecting member (<NUM>) of the pair of toothed arc-shaped connecting members (<NUM>) are arranged opposite to each other on both sides of the worm (<NUM>) and are substantially in the same horizontal plane as the worm (<NUM>).