Hollow rotary actuator

Abstract

The present invention relates to an internally hollow rotary actuator in which a drive motor is provided inside a lower housing, and three gear trains for deceleration and three pinion units are respectively provided on an upper housing at 120-degree intervals, gear coupling is achieved in such a manner that decelerated rotational power is transmitted between a rotor worm wheel serving as an output end of a drive motor and a ring gear integrally formed on a rotary table. According to the internal hollow type rotation actuator, a rotor worm wheel of a driving motor and a first worm, a second worm and a third worm of a first gear transmission system, a second gear transmission system and a third gear transmission system are subjected to primary speed reduction, and a first worm wheel, a second worm wheel and a third worm wheel and a first small gear unit and a second small gear unit are subjected to secondary speed reduction; a large reduction ratio is obtained through second speed reduction among a fourth worm, a fifth worm and a sixth worm of a third pinion unit and third speed reduction among a first pinion, a second pinion, a third pinion and a ring gear, so that the torque is greatly increased.

Description

Technical Field

[0001] The present invention relates to an actuator, and more particularly to an internal hollow type rotary actuator that minimizes backlash and improves brake torque by combining three gear trains with a rotor worm gear of a drive motor at intervals of 120 degrees, thereby increasing destructive strength. Background Art

[0002] An electric actuator plays a role in rotating or linearly moving a moving object by converting a rotating force generated from a rotating power source into a high-torque rotating force.

[0003] Typically, existing actuators use a direct current (DC) motor as a rotational power source, and the rotor power of the DC motor is torque-converted through a gear train consisting of a worm gear and a plurality of spur gears formed as one at the rotor output end to generate high-torque rotational power from the actuator output end.

[0004] This type of existing electric actuator uses a DC motor with an external housing as a rotational power source. The magnet for sensing the rotational position of the rotor cannot be built into the housing, but is attached separately to the outside. An external Hall sensor is used to sense the rotational position of the rotor, and the Hall sensor is connected to a printed circuit board (PCB) with a built-in motor drive circuit, resulting in a complex structure.

[0005] If the actuator does not use a Hall sensor, it can only perform forward and reverse rotation movements.

[0006] Generally, from the perspective of usage characteristics, the actuator product as a whole has a low housing height and a long length or width, and it is difficult to adopt a structure in which a DC motor having an external housing is vertically mounted at the bottom inside the housing.

[0007] When a DC motor is used, when external pressure is applied from an output shaft that performs forward or reverse rotation, the stopped position needs to be maintained, and thus a worm gear is used to increase the brake torque.

[0008] In order to transmit power to a position where an output shaft exists using a worm wheel and a worm gear for a DC motor, a spur gear is generally used for connection. However, this has the following problems.

[0009] First, since the height of the actuator housing is low, the DC motor is usually placed flat, which makes the assembly structure difficult and increases the cost. In other words, there is a problem in securing the assembly space due to the housing for fixing the DC motor and the bearing of the worm shaft.

[0010] Second, the structure for connecting the motor power supply in the motor controller will become complicated.

[0011] Third, accurate position control in the actuator requires information about the rotational position of the rotor. To this end, a magnet for sensing the rotational position is placed at the bottom of the worm gear of the DC motor and a Hall sensor integrated circuit (IC) for sensing the rotational position is used. This makes the structure of connecting the printed circuit board (PCB) and the Hall sensor to use a DC power supply and sense the rotational position complicated.

[0012] Fourth, the gear transmission system using multiple spur gears in order to obtain a large reduction ratio for the rotational power of the drive motor will result in larger tolerances, so that backlash will become larger and precise positioning will be difficult.

[0013] When holding a meeting inside a vehicle, a rotary actuator is used on the car seat to rotate the car seat to a desired angle so that the passengers can meet face to face.

[0014] The following rotary actuator is disclosed in Korean Patent Publication No. 10-2022-0056821 (Patent Document 1), which includes: a cylindrical outer cover, in which a hollow cylindrical portion is formed protruding from the bottom at the center, and a first height difference portion and a second height difference portion are formed protruding from the inner wall; a drive motor is arranged on the bottom surface of the outer cover, and a first worm gear is integrally formed on the outer periphery of an extension portion extending toward the upper part of a rotor; a speed reduction gear transmission system is arranged on the upper part of the second height difference portion and is combined with the outer periphery of the first worm gear, a first worm gear combined with the first worm gear is formed on one side of a transmission shaft, and a second worm gear is formed on the other side of the transmission shaft; a pinion unit, in which a second worm gear combined with the second worm gear is formed at the lower end, and a pinion gear is integrally formed at the upper end; and a rotating table, in which a ring gear integrally formed on the inner side of the side portion is combined with the pinion gear of the pinion unit to achieve rotation, and a moving object is fixed on the upper surface.

[0015] In order to drive the turntable by reducing the rotation speed of the driving motor, the actuator in Patent Document 1 is structured such that a first worm gear formed on the outer periphery of the rotor of the driving motor is combined with a ring gear formed on the turntable using a single reduction gear transmission system in which a worm and a worm wheel are arranged on a transmission shaft and a single pinion unit.

[0016] The swivel actuator in Patent Document 1 uses a structure in which a gear transmission system is used to transmit rotational power between a driving motor and a small gear unit for driving a turntable. This can reduce the tolerance between gears, but it cannot be completely reduced. In addition, since the brake torque for controlling the left and right rotation of the moving object body (i.e., a car seat) that rotates together with the turntable is small, there is a problem that vibration cannot be suppressed.

[0017] Finally, the actuator in Patent Document 1 cannot minimize backlash and has difficulty in suppressing vibration of the rotary table. Summary of the invention

[0018] Technical issues

[0019] Therefore, the present invention is used to solve the problems of the prior art as described above. One purpose of the present invention is to provide an internal hollow swivel actuator, that is, by combining three gear transmission systems, namely, a first gear transmission system, a second gear transmission system, and a third gear transmission system, which integrally form a worm and a worm wheel on a transmission shaft at intervals of 120 degrees with a cylindrical rotor worm wheel extended from the rotor of a driving motor, and by rotating a rotating table provided with a ring gear through the first pinion unit, the second pinion unit, and the third pinion unit, the backlash can be minimized and the brake torque can be increased to increase the destructive strength.

[0020] Another object of the present invention is to provide an internal hollow swivel actuator, which suppresses the left and right displacement of the two ends of the three transmission shafts in the bearing outer cover by setting fixing screws in the bearing outer cover, thereby eliminating the tolerance generated when the gears are connected and achieving zero backlash.

[0021] Another object of the present invention is to provide an internal hollow swivel actuator, wherein three gear transmission systems are combined with the rotor worm gear inside the upper outer cover and fixing screws are used to suppress the left and right displacement of the three transmission shafts, thereby minimizing the backlash and suppressing the vibration of the rotating table.

[0022] Another object of the present invention is to provide an internal hollow swivel actuator, that is, a driving motor is arranged in a lower outer cover, and a first gear transmission system, a second gear transmission system, a third gear transmission system and a first pinion unit, a second pinion unit, and a third pinion unit are arranged in an upper outer cover stacked and assembled on the lower outer cover, so that the driving motor and the gear transmission system can be easily divided, thereby seeking to improve the efficiency of the assembly operation.

[0023] Technical Solution

[0024] In order to achieve the above-mentioned purpose, the internal hollow rotary actuator of the present invention is characterized in that it comprises: a lower outer cover, in which a hollow cylindrical portion is formed in the center protruding upward; an upper outer cover, which is stacked and assembled on the upper part of the lower outer cover, and a through hole is formed in the center so that the hollow cylindrical portion protrudes upward; a drive motor is arranged on the bottom surface of the lower outer cover, and the outer periphery of the cylindrical rotor support extending toward the upper part of the rotor is formed as a whole with the cylindrical rotor worm gear; a first gear transmission system, a second gear transmission system, and a third gear transmission system are respectively arranged and combined at intervals of 120 degrees on the outer periphery of the rotor worm gear protruding toward the upper outer cover, and a gear transmission system is formed on one side of the first transmission shaft, the second transmission shaft, and the third transmission shaft, which is connected to the rotor worm gear by combining with the rotor worm gear. The first worm, the second worm and the third worm that realize the first deceleration have the first worm wheel, the second worm wheel and the third worm wheel formed on the other side of the first transmission shaft, the second transmission shaft and the third transmission shaft; the first pinion unit, the second pinion unit and the third pinion unit have the fourth worm, the fifth worm and the sixth worm formed at the lower end respectively for realizing the second deceleration by combining with the first worm wheel, the second worm wheel and the third worm wheel gears, and have the first pinion, the second pinion and the third pinion gear formed in one piece at the upper end respectively; and a rotating table for realizing the third deceleration by combining the ring gear formed in one piece on the inner side of the side portion with the first pinion, the second pinion and the third pinion gear of the first pinion unit, the second pinion unit and the third pinion unit.

[0025] The two ends of the first transmission shaft, the second transmission shaft and the third transmission shaft can be supported by multiple bearings in a rotatable manner, and multiple fixing screws are set in the bearing outer cover that houses the multiple bearings to prevent the first transmission shaft, the second transmission shaft and the third transmission shaft from being displaced left and right.

[0026] The internal hollow rotary actuator of the present invention may further include a plurality of fixing screw adjustment through holes formed on the wall surface of the upper outer cover, for fixing the first transmission shaft, the second transmission shaft, and the third transmission shaft by pushing the plurality of fixing screws toward one side from the outside.

[0027] Furthermore, the first reduction ratio of the first reduction, the second reduction ratio of the second reduction, and the third reduction ratio of the third reduction can be set to gradually decrease toward the rear end.

[0028] The drive motor may include: a rotor, provided with a cylindrical rotor support body with a cup-shaped lower end, which is rotatably connected to the outer periphery of the hollow cylindrical part; a stator, which is arranged on the outside of the rotor with a gap, and is arranged at the bottom of the outer cover to drive the rotor to rotate by generating a rotating magnetic field; a first bearing and a second bearing, which are arranged between the cup-shaped lower end of the rotor support body and the lower end of the hollow cylindrical part, support the rotor in a rotatable manner, and are stacked in series; and a bearing bracket, which is crimped to the outer periphery of the hollow cylindrical part to crimp the second bearing.

[0029] The internal hollow rotation actuator of the present invention may also include: a first bearing and a second bearing, which are arranged between the lower end of the cylindrical rotor support body and the lower end of the hollow cylindrical part of the lower outer cover, supporting the rotor in a rotatable manner, and are stacked in series; and a third bearing, used to support the rotating table on the outer periphery of the upper end of the hollow cylindrical part in a rotatable manner.

[0030] Furthermore, the internal hollow type rotary actuator of the present invention may further include a bearing holder disposed between the second bearing and the third bearing in a manner of press-fitting the second bearing by being press-fitted to the outer circumference of the cylindrical rotor support body.

[0031] In particular, the internal hollow rotary actuator of the present invention may further include a first support shaft, a second support shaft, and a third support shaft, whose lower ends respectively pass through the bottom of the upper outer cover to be fixedly arranged to rotatably support the first pinion unit, the second pinion unit, and the third pinion unit.

[0032] The virtual circle formed by the first support shaft, the second support shaft, and the third support shaft can form the same concentric circle with the rotating table. The first support shaft, the second support shaft, and the third support shaft can be arranged at intervals of 120 degrees on the virtual circle. The first pinion, the second pinion, and the third pinion can realize gear coupling at three positions of the ring gear at intervals of 120 degrees.

[0033] Furthermore, a first virtual circle formed by the rotor support, the cylindrical rotor worm wheel, the first worm, the second worm, and the third worm and a second virtual circle formed by the first support shaft, the second support shaft, the third support shaft, and the rotating table can be set with the same concentric circle as a reference.

[0034] Effects of the Invention

[0035] As described above, the present invention provides a transmission structure that minimizes the number of combined gears by forming a worm and a worm wheel on a transmission shaft in an integrated manner with a gap, thereby minimizing the backlash. Ultimately, the present invention can reduce the overall size and secure space compared to the existing gear transmission system that combines multiple spur gears, thereby increasing the degree of design freedom and saving costs.

[0036] Furthermore, in the present invention, a brushless DC motor (BLDC) driving motor is disposed at the bottom of the lower housing, and at the upper part, three gear transmission systems in which a worm and a worm wheel are formed integrally on the transmission shaft with intervals are combined with a rotor worm wheel formed at an interval of 120 degrees at the output end of the rotor protruding from the inside of the upper housing, thereby minimizing backlash and suppressing vibration of the turntable. That is, in the present invention, three gear transmission systems in which a worm and a worm wheel are formed integrally on the transmission shaft with intervals are combined with a cylindrical worm wheel extending from the outer periphery of the rotor of the driving motor to minimize backlash and increase brake torque to increase the destructive strength.

[0037] Generally, a rotary actuator is rotatably supported by a fixed frame fixedly installed on a floor in a vehicle, and a car seat is installed on a rotary table that is installed above the rotary actuator and rotates.

[0038] In this case, the rotary actuator is electrically driven and allows the rotary table to rotate relative to the fixed frame in a desired direction according to the switch operation of the user. The driving of the rotary actuator is linked to the activation (turning on) of the operating switch to rotate at a preset angle or to rotate by linkage with the activation (turning on) of the operating switch, and if the activation of the operating switch is stopped (turned off), it will stop at the rotated position.

[0039] When the user electrically drives the rotary actuator to rotate according to the rotation angle and then stop, the output part of the drive motor must have a specified braking torque (Brake Torque) according to the activation (opening) of the operating switch, that is, a specified braking torque (Brake Torque) is provided between the rotor worm gear and the rotating table.

[0040] Since the rotating table driven for rotation has a rotational inertia force, in order to stop it at a desired position, it is necessary to increase the brake torque determined by the transmission mechanism of the gear transmission system and the pinion unit connected between the rotor worm wheel and the ring gear of the rotating table.

[0041] The rotating table on which the car seat for the user is installed cannot withstand a large force because the number of meshing gears between the ring gear and the pinion gear installed on the periphery of the rotating table is small. In this case, since the gear diameter of the pinion gear, which is a spur gear (spurgear), is smaller than the ring gear, the number of meshing gears between the ring gear and the pinion gear is 1ea to 1.5ea per pinion gear.

[0042] Therefore, if you want to increase the brake torque between the ring gear and the pinion gear, you should maximize the number of meshing gears (the number of teeth on the gears in contact).

[0043] In this case, three gear transmission systems are arranged to form an equilateral triangle on the rotor worm gear at intervals of 120 degrees, and the three pinions of the three pinion units are evenly arranged at intervals of 120 degrees to be gear-coupled at three positions of the ring gear of the turntable. This transmission mechanism can obtain a larger braking torque (Brake Torque) than the following transmission mechanism, that is, using a single or a pair of gear transmission systems and a single or a pair of pinion units to make the rotor worm gear gear-coupled at one position or two positions of the ring gear of the turntable.

[0044] That is, in the present invention, three gear transmission systems are set on the rotor worm gear, and three pinions of three pinion units are gear-coupled at three positions of the ring gear of the turntable. By adopting this transmission mechanism, a larger brake torque than before can be obtained.

[0045] When the braking torque is increased in the manner described above, the degree of freedom in selecting the material of the gear will increase.

[0046] In the past, gears were made of SUS processed products, but now sintered metal or plastic processed products can be used, which makes them more competitive in terms of cost and mass production, making it preferable to adopt a design that increases the number of meshing gear teeth when the gears are combined.

[0047] In the present invention, three gear transmission systems in the form of an equilateral triangle are arranged on concentric circles at intervals of 120 degrees along the periphery of the hollow rotor worm wheel, and three pinions of three pinion gear units are also arranged on concentric circles of the hollow rotor worm wheel at intervals of 120 degrees. The three positions of the ring gear of the rotating table are combined with balanced force gears, which is conducive to suppressing the vibration of the rotating table. For this reason, in the present invention, relative to the hollow rotor worm wheel, the virtual circle composed of the three worms of the three gear transmission systems, the virtual circle composed of the three pinions of the three pinion gear units, and the rotating table are all on concentric circles.

[0048] Furthermore, as described above, if the three gear transmission systems are arranged in an equilateral triangle structure inside the upper housing, the tolerance between the gears can be reduced, but it is difficult to completely reduce it. That is, although the gap between the gears can be minimized, the tolerance between the gears will cause play, which may cause the rotating table connected to the pinion unit gear to shake left and right.

[0049] This problem may be caused by the left-right displacement of the two ends of the transmission shaft forming the gear transmission system in the bearing housing. Therefore, in the present invention, a fixing screw is added to the rear end of the bearing housing in a manner to suppress the left-right displacement of the two ends of the transmission shaft in the bearing housing, and the tolerance (clearance) generated when the gears are connected between the worm wheel of the gear transmission system and the worm of the pinion unit can be eliminated by suppressing the left-right displacement of the transmission shaft. Finally, zero backlash can also be achieved by eliminating the gap between the pinion of the pinion unit and the ring gear of the rotating table. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figures 1 to 3 They are respectively a three-dimensional view, a top view and a Figure 2 AA line section view in.

[0051] Figure 4 This is a perspective view of an isolated rotating table of an internal hollow type rotary actuator according to a preferred embodiment of the present invention.

[0052] Figure 5 This is a top view of an internal hollow type rotary actuator without a rotating table according to a preferred embodiment of the present invention.

[0053] Figures 6a to 6c They are Figure 5 Cross-sectional views of line BB, line CC and line DD.

[0054] Figure 7 as well as Figure 8 They are respectively an exploded perspective view and a completely exploded perspective view of each module of the internal hollow type rotary actuator according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0055] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0056] In the process of description, in order to achieve clarity and convenience of description, the size or shape of the structural elements shown in the drawings may be exaggerated. In addition, a plurality of terms specifically defined in consideration of the structure and function of the present invention may become different according to the intention or practice of the user or application personnel. The definition of such terms should be based on the content of the entire specification.

[0057] The rotation actuator of the present invention is used to rotate the rotating table and the moving object body left and right together, that is, to rotate the vehicle seat left and right. In the following description, an internal hollow rotation actuator that uses a brushless DC motor (BLDC) drive motor as a power source to drive the moving object is described.

[0058] It is difficult to use a brushless DC motor (BLDC) for ordinary motors. For this part, the present invention increases the motor torque by vertically erecting the motor at the bottom of the outer cover and increasing the size in the diameter direction. The drive motor is provided with a stator and a rotor at the bottom surface of the outer cover, and an inner rotor brushless DC motor (BLDC) is used.

[0059] In the actuator of the prior art, the motor part, gear part and selection part formed by the DC motor are formed by separate parts. When assembled into the body of the product using the actuator, there are many problems such as assembly tolerance and parts handling.

[0060] The rotary actuator of the present invention can play a role in causing the moving object arranged on the rotating table to rotate together with the rotating table.

[0061] The rotary actuator of the present invention includes: a drive motor of a brushless DC motor (BLDC) type; a gear transmission system for transmitting the rotational power of the drive motor to a rotating table to increase torque by reducing speed; and a rotating table that rotates by the output of the gear transmission system, and the moving object is combined with the rotating table to rotate together with the rotating table. In this case, the drive motor, the gear transmission system and the rotating table are assembled in an integral manner on the outer cover.

[0062] The rotary actuator of the present invention is formed in the shape of a disk, the inner side of which is hollow, and a through hole for cable lead-out is formed in the center portion, and a plurality of coupling holes for connecting to a moving object (e.g., an electric seat) are formed in the upper portion of the rotating body (rotating table), for example, four coupling holes are formed, and the coupling holes can be combined with fixing bolts for fixing to the electric seat.

[0063] The actuator of the present invention is provided with an annular stator at the bottom of the outer cover, and a rotor with an integrated worm gear is provided on the upper side of the inner cover. The rotor worm gear is combined with the worm gear of the transmission shaft forming the gear transmission system, the worm gear formed at the other end of the transmission shaft is combined with the worm at the lower end of the pinion unit, and the pinion at the upper end of the pinion unit is combined with the annular gear formed on the inner side of the side portion of the rotating table, thereby driving the rotating table to rotate.

[0064] In this case, the three gear transmission systems are arranged in an equilateral triangle at intervals of 120 degrees on the rotor worm gear, and are combined with the respective worm gears of the transmission shafts forming the three gear transmission systems. The respective worm wheels formed at the other end of the transmission shafts are combined with the worms located at the lower ends of the three pinion gear units, and the three pinion gears located at the upper ends of the three pinion gear units are combined with three positions of the ring gear formed on the inner side of the side portion of the turntable at intervals of 120 degrees, thereby driving the turntable to rotate with a balanced force.

[0065] As described above, the three gear transmission systems are arranged to form an equilateral triangle on the rotor worm gear at intervals of 120 degrees, and the three pinions of the three pinion units are evenly arranged at intervals of 120 degrees to engage with the gears at three positions of the ring gear of the turntable. This transmission mechanism can increase the braking torque (Brake Torque) by increasing the number of meshing gear teeth when the gears are engaged, compared with the following transmission mechanism, that is, using a single or a pair of gear transmission systems and a single or a pair of pinion units to enable the rotor worm gear to engage with the gears at one position or two positions of the ring gear of the turntable.

[0066] In the present invention, with respect to the hollow rotor worm gear, the virtual circle formed by the three worms of the three gear transmission systems, the virtual circle formed by the three pinions of the three pinion units, and the rotating table are all on concentric circles, thereby suppressing vibration of the rotating table.

[0067] Reference Figures 1 to 8The internal hollow rotary actuator 200 of a preferred embodiment of the present invention comprises: a lower outer cover 10, in which a hollow cylindrical portion 11 is formed in the center and protrudes upward; an upper outer cover 15, which is stacked and assembled on the upper part of the lower outer cover 10, and a through hole 15c is formed in the center so that the hollow cylindrical portion 11 protrudes upward; a driving motor 100, which is arranged at the bottom 10b of the lower outer cover 10, and the outer periphery of the extension portion extending toward the upper part of the rotor 30 is formed as a whole with the rotor worm wheel 35; a first gear transmission system 70a, a second gear transmission system 70b, and a third gear transmission system 70c, which are respectively arranged at the bottom 15b of the upper outer cover 15 and combined with the outer periphery of the rotor worm wheel 35, and a first worm 72a, a second worm 72b, and a third worm gear 72b, which are gear-coupled with the rotor worm wheel 35, are formed on one side of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c. The rod 72c is formed with a first worm gear 73a, a second worm gear 73b, and a third worm gear 73c on the other side of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c; the first pinion unit 80a, the second pinion unit 80b, and the third pinion unit 80c are respectively formed with a fourth worm 81a, a fifth worm 81b, and a sixth worm 81c gear-coupled with the first worm gear 73a, the second worm gear 73b, and the third worm gear 73c at the lower end, and are respectively formed with an integrated first pinion gear 82a, a second pinion gear 82b, and a third pinion gear 82c at the upper end; and the rotating table 20 is rotated by making the ring gear 24 formed in an integral manner on the inner side of the side surface portion 23 be gear-coupled with the first pinion gear 82a, the second pinion gear 82b, and the third pinion gear 82c of the first pinion gear unit 80a, the second pinion gear unit 80b, and the third pinion gear unit 80c.

[0068] In the lower housing 10 , a hollow cylindrical portion 11 protrudes from the center, and a driving motor 100 is installed in a bottom 10 b space between the hollow cylindrical portion 11 and the circular wall surface 10 a .

[0069] Furthermore, the upper cover 15 is stacked and assembled on the upper part of the lower cover 10, and is fixed by tightening a plurality of fixing bolts or screws 17. The first gear train 70a, the second gear train 70b, the third gear train 70c and the first pinion unit 80a, the second pinion unit 80b, and the third pinion unit 80c are accommodated in the bottom 15b of the upper cover 15, and a rotating table 20 is rotatably provided on the upper part thereof.

[0070] The driving motor 100 generates a rotational power, and the first gear transmission system 70a, the second gear transmission system 70b, and the third gear transmission system 70c receive the rotational power and realize torque conversion by decelerating the speed, thereby generating a decelerated rotational power with increased torque.

[0071] In addition, the first pinion unit 80a, the second pinion unit 80b, and the third pinion unit 80c are respectively arranged in the first worm gear 73a, the second worm gear 73b, and the third worm gear 73c of the first gear transmission system 70a, the second gear transmission system 70b, and the third gear transmission system 70c along the vertical direction, and play the role of transmitting the rotational power after receiving the decelerated torque to the ring gear 24 integrally formed on the rotating table 20.

[0072] The drive motor 100 can be constructed as an internal rotor type in which the rotor 30 is arranged on the inner side of the stator 40, including: a rotor 30, which is rotatably connected to the outer periphery of the hollow cylindrical portion 11 of the lower cover 11; and a stator 40, which is arranged on the outer side of the rotor 30 with a gap, and is arranged on the upper surface of the lower cover 11 in order to drive the rotor 30 to rotate by generating a rotating magnetic field, and a rotor worm gear 35 is integrally formed on the outer periphery in an extension portion extending toward the upper part of the rotor 30.

[0073] In the rotor 30, the magnet 31 arranged on the outer periphery of the back yoke 32 located on the inner side can be composed of a plurality of segmented magnet pieces with N poles and S poles or a magnet with N poles and S poles multi-pole segmented magnetization in a ring-shaped magnet, and the back yoke 32 will be arranged on the back side of the magnet 31 to form a magnetic circuit.

[0074] The stator 40 includes: a stator core 45, having a plurality of teeth 41 formed in a T-shape and a back yoke 42 connected to the plurality of teeth 41 to form a magnetic circuit; an upper insulator 44a and a lower insulator 44b made of insulating material, which are formed as a whole in a manner of surrounding the outer circumference of the coil 43 for winding the respective teeth; and a coil 43 wound on the outer circumference of the insulators 44a and 44b.

[0075] In this case, the insulators 44 a and 44 b are formed integrally with the winding bobbin surrounding the plurality of teeth 41 and the back yoke 42 as a stator support body.

[0076] For example, the rotary actuator 200 of the present invention can make the drive motor 100 consist of a DC brushless motor with a 20-pole-18-slot structure. And, for example, when the coil 43 of the stator 40 is wound around the plurality of teeth 41, the coil 43 is wound in a three-phase structure of U, V, and W, and the other end of the three-phase coil 43 of U, V, and W can be connected by a Y-connection method. In particular, for example, the drive motor 100 can be driven by a 6-stepping electric wave drive method using an inverter after receiving a rotor position signal from two or three Hall sensors in the motor drive circuit.

[0077] A first bearing 61 and a second bearing 62 for rotatably supporting the rotor 30 are provided on the outer circumference of the hollow cylindrical portion 11 of the lower cover 11 .

[0078] The upper cover 15 is provided with a first concave groove 16a, a second concave groove 16b, and a third concave groove 16c at a bottom 15b at intervals of 120 degrees, with the through hole 15c located at the center of the circular wall surface 15a as the center.

[0079] The first gear transmission system 70a, the second gear transmission system 70b, and the third gear transmission system 70c are respectively arranged in the first groove 16a, the second groove 16b, and the third groove 16c of the upper outer cover 15, and are arranged at an average interval of 120 degrees with the hollow rotor worm wheel 35 protruding upward through the through hole 15c as the center. The first worm 72a, the second worm 72b, and the third worm 72c gear-coupled with the rotor worm wheel 35 are formed on one side of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c, and the first worm wheel 73a, the second worm wheel 73b, and the third worm wheel 73c are formed on the other side of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c.

[0080] The first groove 16a, the second groove 16b, and the third groove 16c form a groove shape for accommodating the first gear transmission system 70a, the second gear transmission system 70b, the third gear transmission system 70c and the first pinion unit 80a, the second pinion unit 80b, and the third pinion unit 80c.

[0081] The first gear transmission system 70a, the second gear transmission system 70b, and the third gear transmission system 70c are evenly arranged at intervals of 120 degrees with the hollow rotor worm gear 35 protruding toward the upper part of the upper outer cover 15 as the center, and the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c are rotatably supported at both ends by three pairs of bearings 74a, 74b, 74c, 74d, 74e, and 74f.

[0082] In this case, in the present invention, fixing screws 77a, 77b, 77c, 77d, 77e, 77f are respectively added to the rear ends of the bearing outer covers 75a, 75b, 75c, 75d, 75e, 75f in a manner to suppress the left and right displacement of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c in the bearing outer covers 75a, 75b, 75c, 75d, 75e, 75f for supporting three pairs of bearings 74a, 74b, 74c, 74d, 74e, 74f, thereby limiting the left and right movement of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c.

[0083] The fixing screws 76a, 76b, 76c, 76d, 76e, 76f are formed with male threads on the outer periphery of the main body, and a "-" or "+" shaped groove is formed at the rear end to accommodate the front end of the screwdriver, and the front end can be formed into a curved surface or a flat surface.

[0084] The fixing screws 76a, 76b, 76c, 76d, 76e, and 76f can be combined in the following form, i.e., by forming a female thread in a through hole that passes through the rear end of the bearing outer cover 75a, 75b, 75c, 75d, 75e, and 75f to the inside and threading the fixing screws 76a, 76b, 76c, 76d, 76e, and 76f, the front ends of the six fixing screws 76a, 76b, 76c, 76d, 76e, and 76f push and press the two ends of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c.

[0085] Preferably, the fixing screws 76a, 76b, 76c, 76d are provided on the six bearing covers 75a, 75b, 75c, 75d, 75e, 75f of the six bearings 74a, 74b, 74c, 74d, 74e, 74f that rotatably support the two ends of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c. It is also possible that the bearing covers 75a, 75b, 75c, 75d, 75e, 75f that are only provided on one side in a manner of supporting one side end of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c can be pushed toward one side to suppress left and right movement.

[0086] The fixing screws 76a, 76b, 76c, 76d, 76e, 76f may have their front ends protruded into a spherical shape to contact the ends of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c, or may have their front ends in a planar shape. In the present invention, since the rotation speed (rpm) of the drive motor 100 is low and the gear ratio is large, the shape of the front ends of the fixing screws 76a, 76b, 76c, 76d, 76e, 76f will not have a significant impact.

[0087] The first pinion unit 80a, the second pinion unit 80b, and the third pinion unit 80c are arranged on the first support shaft 83a, the second support shaft 83b, and the third support shaft 83c which are arranged at the lower end and pass through the bottom 15b of the upper outer cover 15. The fourth worm 81a, the fifth worm 81b, and the sixth worm 81c which are gear-coupled with the first worm gear 73a, the second worm gear 73b, and the third worm gear 73c are rotatably coupled at the lower ends of the first support shaft 83a, the second support shaft 83b, and the third support shaft 83c, respectively. At the upper end, the first pinion gear 82a, the second pinion gear 82b, and the third pinion gear 82c are formed as a whole with the fourth worm gear 81a, the fifth worm gear 81b, and the sixth worm gear 81c.

[0088] In this case, the fourth worm 81a, the fifth worm 81b, the sixth worm 81c and the first pinion 82a, the second pinion 82b, and the third pinion 82c can be formed as a whole by injection molding using synthetic resin, or they can be manufactured separately and then assembled together to be rotatably connected to the support shaft 83.

[0089] The rotating platform 20 includes a circular upper plate 21 and a side surface 23 extending downward from the outer periphery of the upper plate 21. A plurality of coupling holes 22 for coupling with a body (e.g., an electric car seat) as a moving object disposed on the rotating platform 20 may be formed through the upper plate 21.

[0090] A central through hole 25 is formed at the center of the upper plate 21 for passing cables for connecting the stator coil 43 of the drive motor 100 and a plurality of Hall sensors provided in the Hall sensor assembly to a motor drive circuit provided outside the rotary actuator 200 .

[0091] Therefore, after the cable is introduced to the lower part through the central through hole 25 provided at the center of the upper plate and the hollow cylindrical portion 11 of the lower cover 10, it is connected to the stator coil 43 and the Hall sensor assembly 50 through the through hole 19a formed at the bottom of the lower cover 10. The through hole 19a is covered by assembling the through hole cover 19.

[0092] In this case, the printed circuit board PCB forming the motor driving circuit will be connected to the stator coil 43 and the Hall sensor assembly 50 of the driving motor 100 disposed inside through the cable after being disposed outside the rotary actuator 200. However, the printed circuit board PCB forming the motor driving circuit may also be built in the space formed at the lower portion of the lower housing 10 or the lower side of the upper housing 15.

[0093] When the cable is used to connect from the outside to the stator coil 43 and the Hall sensor assembly 50 of the drive motor 100 arranged inside, the cable needs to be composed of 8 metal wires, which are respectively composed of the U output terminal, V output terminal, W output terminal of the inverter circuit, 3 Hall sensors H1~H3, Vcc, and GND.

[0094] As described above, in the present invention, the hollow cylindrical portion 11 protruding from the center of the lower housing 10 extends upward through the through hole 15c of the upper housing 15 and is exposed through the through hole 25 of the turntable 20. Finally, the motion control cable of the drive motor 100 can be easily connected from the outside to the stator coil 43 and the Hall sensor assembly 50 provided in the lower housing 10 through the through hole 11a of the hollow cylindrical portion 11, and even if the car seat provided on the upper part of the turntable rotates, it will not interfere with the cable.

[0095] Furthermore, the upper end of the hollow cylindrical portion 11 of the lower outer cover 10 will be located in the central through hole 25 , and a third bearing 63 may be provided at the center of the inner circumferential surface of the upper plate 21 so as to rotatably support the turntable 20 at the outer circumference of the hollow cylindrical portion 11 .

[0096] The third bearing 63 may be formed of a ball bearing with a ball inserted between an inner wheel and an outer wheel. In this case, the outer wheel of the third bearing 63 is supported by the bearing cover 26 protruding from the lower part of the rotating table 20, and the inner wheel of the third bearing 63 is supported by the upper end of the bearing bracket 64 and supported by the hollow cylindrical portion 11 of the lower cover 10.

[0097] In addition, the hollow type rotary actuator 200 has a stopper inserting groove formed at the upper end of the hollow cylindrical portion 11 , and a brake ring 13 is coupled to the stopper inserting groove to prevent the rotary table 20 from being separated.

[0098] A ring gear 24 is integrally formed inside the side surface 23 of the rotating table 20 and is gear-coupled with the first pinion 82a, the second pinion 82b, and the third pinion 82c of the first pinion unit 80a, the second pinion unit 80b, and the third pinion unit 80c.

[0099] As described above, according to the present invention, the first worm 72a, the second worm 72b, the third worm 72c and the first worm wheel 73a, the second worm wheel 73b, the third worm wheel 73c are formed in an integrated manner at intervals on the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c, respectively, so as to minimize the number of combined gears. By changing the structure of the gear transmission system, a transmission structure that can minimize the backlash is provided. Finally, according to the present invention, compared with the existing gear transmission system combining multiple spur gears, the overall size can be reduced and the space can be ensured, thereby increasing the degree of freedom in design and reducing costs.

[0100] Furthermore, in the present invention, a brushless DC motor (BLDC) drive motor 100 can be disposed at the bottom 10b of the lower outer cover 10 and the first gear transmission system 70a, the second gear transmission system 70b, and the third gear transmission system 70c can be evenly disposed inside the upper outer cover 15 at intervals of 120 degrees at the bottom 15b of the upper outer cover 15 assembled on the upper part of the lower outer cover 10, so that the backlash can be minimized while suppressing the generation of vibration. The first gear transmission system 70a, the second gear transmission system 70b, and the third gear transmission system 70c form a first worm 72a, a second worm 72b, a third worm 72c, and a first worm wheel 73a, a second worm wheel 73b, and a third worm wheel 73c as a whole with intervals on the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c.

[0101] In the present invention, as described above, the three first gear transmission systems 70a, the second gear transmission system 70b, and the third gear transmission system 70c are evenly arranged at intervals of 120 degrees and combined with the rotor worm gear 35 of the drive motor 100, and the three fourth worm gears 81a, the fifth worm gear 81b, the sixth worm gear 81c and the first pinion gear 82a, the second pinion gear 82b, and the third pinion gear 82c of the first pinion unit 80a, the second pinion gear unit 80b, and the third pinion gear 80c are used to realize gear coupling at three positions of the ring gear 24.

[0102] Therefore, in the present invention, with the use of a transmission mechanism that combines three first gear transmission systems 70a, a second gear transmission system 70b, and a third gear transmission system 70c and a first pinion unit 80a, a second pinion unit 80b, and a third pinion unit 80c, the ring gear 24 is rotated by the three first pinions 82a, the second pinion 82b, and the third pinion 82c arranged at the same intervals to drive the turntable 20 to rotate. Ultimately, the braking torque (Brake Torque) can be increased by increasing the number of meshing gears (the number of gear teeth in contact), thereby increasing the destructive strength.

[0103] Furthermore, in the present invention, relative to the hollow rotor worm gear 35, a virtual circle formed by the three first worms 72a, the second worms 72b, and the third worms 72c of the three first gear transmission systems 70a, the second gear transmission system 70b, and the third gear transmission system 70c and a virtual circle formed by the three first pinion gears 82a, the second pinion gear 82b, and the third pinion gear 82c of the three first pinion gear units 80a, the second pinion gear unit 80b, and the third pinion gear unit 80c and the rotating table 20 can all be arranged on concentric circles, thereby suppressing the vibration of the rotating table.

[0104] As described above, if the first gear transmission system 70a, the second gear transmission system 70b, and the third gear transmission system 70c are arranged inside the upper housing, the tolerance between the gears can be reduced, but it is difficult to completely eliminate it. That is, although the gap between the gears is minimized, the tolerance between the gears causes a backlash, which may cause the rotating table 20 and the driven object coupled to the first pinion gear 82a, the second pinion gear 82b, and the third pinion gear 82c to shake left and right.

[0105] This problem may be caused by the left and right displacement of the two ends of the transmission shaft forming the gear transmission system in the bearing housing. In the present invention, the two ends of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c are rotatably supported by six bearings 74a, 74b, 74c, 74d, 74e, and 74f, respectively.

[0106] The six bearings 74a, 74b, 74c, 74d, 74e, 74f are built in the bearing housing 75a, 75b, 75c, 75d, 75e, 75f fixedly provided at the bottom 15b of the upper housing 15. In the present invention, fixing screws 76a, 76b, 76c, 76d, 76e, 76f are added to the rear ends of the bearing housings 75a, 75b, 75c, 75d, 75e, 75f so as to suppress the left-right displacement of both ends of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c in the bearing housings 75a, 75b, 75c, 75d, 75e, 75f.

[0107] Ultimately, the tolerance clearance generated when the gears are combined between the first worm gear 73a, the second worm gear 73b, the third worm gear 73c of the first gear transmission system 70a, the second gear transmission system 70b, the third gear transmission system 70c and the fourth worm gear 81a, the fifth worm gear 81b, the sixth worm gear 81c of the first pinion unit 80a, the second pinion unit 80b, the third pinion unit 80c is eliminated by suppressing the left and right displacement of the first transmission shaft 71a, the second transmission shaft 71b, the third transmission shaft 71c. In addition, zero tooth backlash can also be achieved by eliminating the gap between the first pinion gear 82a, the second pinion gear 82b, the third pinion gear 82c of the first pinion gear unit 80a, the second pinion gear unit 80b, the third pinion gear 80c and the ring gear 24 of the rotating table 20.

[0108] As described above, the crimping connection between the fixing screws 76a, 76b, 76c, 76d, 76e, 76f and the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c can be made after the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c are assembled inside the upper outer cover 15, and the fixing screws 76a, 76b, 76c, 76d, 76e, 76f are moved forward in one direction through the fixing screw adjustment through holes 12 formed on the wall surface 15a of the upper outer cover 15 to push the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c, thereby suppressing the left and right movement of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c.

[0109] Below, refer to Figures 1 to 8 The operation of the internal hollow swivel actuator 200 of the present invention will be described.

[0110] First, when the internal hollow swivel actuator 200 of the present invention starts the brushless DC motor (BLDC) drive motor 100 disposed at the bottom of the lower outer cover 10, as the rotor 30 rotates, the rotor worm gear 35 integrally formed on the upper side of the rotor 30 also rotates in the same direction.

[0111] If the rotor worm gear 35 rotates, the first deceleration is achieved by rotating the first worm 72a, the second worm 72b, and the third worm 72c of the first gear transmission system 70a, the second gear transmission system 70b, and the third gear transmission system 70c, which are arranged at intervals of 120 degrees on the outer circumference of the rotor worm gear 35 and gear-coupled, and the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c will also rotate.

[0112] Finally, the first worm gear 73a, the second worm gear 73b, and the third worm gear 73c formed on the other side of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c cause the fourth worm 81a, the fifth worm 81b, and the sixth worm 81c of the first pinion unit 80a, the second pinion unit 80b, and the third pinion unit 80c to rotate to achieve the second deceleration.

[0113] Therefore, the first pinion 82a, the second pinion 82b, and the third pinion 82c located at the upper ends of the first pinion unit 80a, the second pinion unit 80b, and the third pinion unit 80c are driven to rotate, and the first pinion 82a, the second pinion 82b, and the third pinion 82c make the ring gear 24 set on the rotating table 20 rotate in the same direction with a gear combination at an interval of 120 degrees, thereby realizing the third deceleration.

[0114] Generally, the reduction ratio of the reduction gear is calculated by (the number of teeth of the driven gear / the number of teeth of the driving pinion gear). When a multi-stage gear combination is realized, the total reduction ratio is calculated by the product of each reduction ratio.

[0115] In this case, in the present invention, if the gear ratio reduction ratio R1 between the rotor worm gear 35 of the drive motor 100 and the first worm 72a, the second worm 72b, the third worm 72c of the first gear transmission system 70a, the second gear transmission system 70b, the third gear transmission system 70c is set to 20:1 and the gear ratio reduction ratio R2 between the first worm gear 73a, the second worm gear 73b, the third worm gear 73c and the fourth worm gear 81a, the fifth worm gear 81b, the sixth worm gear 81c is set to 10:1 and the gear ratio reduction ratio R3 between the first pinion 82a, the second pinion 82b, the third pinion gear 82c and the ring gear 24 is set to 2:1, the total reduction ratio can reach 400:1.

[0116] In this case, the gear ratio (reduction ratio) between the gears is set to gradually decrease toward the output end (ie, R1>R2>R3), and stable high torque power can be obtained even if a large torque conversion is formed at the terminal.

[0117] In the rotary actuator 200 of the present invention, for example, when the brushless DC motor (BLDC) drives the motor 100 to rotate at a speed of 800 rpm, if the total reduction ratio reaches 400:1 through three-stage deceleration, it will be decelerated at 400:1, the rotation speed of the rotating table 20 will drop to a low speed of 2 rpm, and the rotational torque will increase 400 times, thereby greatly increasing the torque.

[0118] When the rotary actuator 200 of the present invention is used in a car seat, when holding a meeting in the vehicle, the car seat can be rotated to a desired angle so that the passengers can hold the meeting in a face-to-face state.

[0119] As described above, in the present invention, the generation of vibration can be suppressed while minimizing the backlash by arranging the first gear transmission system, the second gear transmission system, the third gear transmission system and the first pinion unit, the second pinion unit and the third pinion unit at intervals of 120 degrees inside the upper housing.

[0120] Furthermore, in the present invention, fixing screws are added to the rear end of the bearing cover in a manner to suppress the left-right displacement of the two ends of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c in the bearing cover. In the present invention, after the first gear transmission system, the second gear transmission system, and the third gear transmission system are assembled inside the upper cover, the fixing screws are moved forward in one direction to push the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c, thereby suppressing the left-right movement of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c.

[0121] Finally, by tightening the fixing screws to suppress the left and right displacement of the first transmission shaft 71a, the second transmission shaft 71b, and the third transmission shaft 71c, the tolerance gap generated when the first worm wheel, the second worm wheel, and the third worm wheel of the first gear transmission system, the second gear transmission system, and the third gear transmission system are combined with the fourth worm gear, the fifth worm gear, and the sixth worm gear of the first pinion unit, the second pinion unit, and the third pinion unit is eliminated. In addition, zero tooth backlash can also be achieved by eliminating the gap between the first pinion gear, the second pinion gear, and the third pinion gear of the first pinion gear unit, the second pinion gear unit, and the third pinion gear and the ring gear of the rotating table.

[0122] Furthermore, in the present invention, the gear transmission system is spaced apart so that the worm and the output worm wheel are integrated into one body, the rotor worm wheel integrated into the upper part of the rotor is combined with the worm gear, and the worm wheel is combined with the worm gear of the pinion unit, which will realize transmission and deceleration by transmitting rotational power to the rotating table, thereby performing torque conversion.

[0123] In particular, in the present invention, the drive motor is arranged in the lower outer cover, and the first gear transmission system, the second gear transmission system, the third gear transmission system and the first pinion unit, the second pinion unit, and the third pinion unit are stacked and assembled in the upper outer cover, so that the division and organization between the drive motor and the gear transmission system can be easily achieved, and the efficiency of the assembly operation can be improved.

[0124] The present invention is illustrated and described above by taking specific preferred embodiments as examples, but the present invention is not limited to the above embodiments, and various changes and modifications can be implemented by ordinary technicians in the technical field to which the invention belongs without departing from the scope of the concept of the present invention.

[0125] Industrial Applicability

[0126] The rotary actuator of the present invention can be applied for the purpose of rotating together with the rotary table so as to rotate a moving object such as a car seat installed on the rotary table to the left and right.

Claims

1. An internal hollow rotary actuator, characterized in that: include: The lower outer cover is formed with a hollow cylindrical portion protruding upward at the center; An upper outer cover is stacked and assembled on the upper part of the lower outer cover, and a through hole is formed in the center portion so that the hollow cylindrical portion protrudes upward; A drive motor is arranged on the bottom surface of the lower housing, and the outer periphery of the cylindrical rotor support extending toward the upper part of the rotor is formed integrally with the cylindrical rotor worm wheel; The first gear transmission system, the second gear transmission system, and the third gear transmission system are respectively arranged and combined at intervals of 120 degrees on the outer periphery of the rotor worm wheel protruding toward the upper outer cover, and the first worm, the second worm, and the third worm are formed on one side of the first transmission shaft, the second transmission shaft, and the third transmission shaft to realize the first reduction by combining with the rotor worm wheel gear, and the first worm wheel, the second worm wheel, and the third worm wheel are formed on the other side of the first transmission shaft, the second transmission shaft, and the third transmission shaft; The first pinion unit, the second pinion unit, and the third pinion unit are respectively formed with a fourth worm, a fifth worm, and a sixth worm at the lower end to realize the second speed reduction by combining with the first worm gear, the second worm gear, and the third worm gear, and are respectively formed with an integrated first pinion, a second pinion, and a third pinion at the upper end; and The rotating table realizes the third reduction by combining the ring gear integrally formed inside the side surface with the first pinion gear, the second pinion gear and the third pinion gear of the first pinion gear unit, the second pinion gear and the third pinion gear unit.

2. The internal hollow type rotary actuator according to claim 1, characterized in that: Both ends of the first transmission shaft, the second transmission shaft and the third transmission shaft are rotatably supported by a plurality of bearings, and a plurality of fixing screws are provided in a bearing outer cover in which the plurality of bearings are built to prevent the first transmission shaft, the second transmission shaft and the third transmission shaft from being displaced left and right.

3. The internal hollow type rotary actuator according to claim 2, characterized in that: It also includes a plurality of fixing screw adjustment through holes formed on the wall surface of the upper outer cover, which are used to fix the first transmission shaft, the second transmission shaft, and the third transmission shaft by pushing the plurality of fixing screws toward one side from the outside.

4. The internal hollow type rotary actuator according to claim 1, characterized in that: The first reduction ratio of the first reduction, the second reduction ratio of the second reduction, and the third reduction ratio of the third reduction are set to gradually decrease toward the rear end.

5. The internal hollow type rotary actuator according to claim 1, characterized in that: The driving motor comprises: The rotor is provided with a cylindrical rotor support body with a cup-shaped lower end, which is rotatably coupled to the outer periphery of the hollow cylindrical portion; a stator, which is arranged outside the rotor with a gap therebetween and is arranged at the bottom of the housing in order to generate a rotating magnetic field to drive the rotor to rotate; A first bearing and a second bearing are provided between a cup-shaped lower end portion of the rotor support body and a lower end of the hollow cylindrical portion, rotatably supporting the rotor, and are stacked in series; and The bearing support is press-fitted to the outer periphery of the hollow cylindrical portion to press-fit the second bearing.

6. The internal hollow type rotary actuator according to claim 1, characterized in that: Also includes: A first bearing and a second bearing are provided between the lower end of the cylindrical rotor support body and the lower end of the hollow cylindrical portion of the lower cover, rotatably supporting the rotor, and are stacked in series; and The third bearing is used to rotatably support the rotating table at the outer periphery of the upper end portion of the hollow cylindrical portion.

7. The internal hollow type rotary actuator according to claim 6, characterized in that: A bearing support is further included, which is disposed between the second bearing and the third bearing in such a manner that the second bearing is pressed against the outer circumference of the cylindrical rotor support body by being pressed against the rotor support body.

8. The internal hollow type rotary actuator according to claim 1, characterized in that: It also includes a first support shaft, a second support shaft, and a third support shaft, the lower ends of which pass through the bottom of the upper outer cover respectively to be fixedly arranged to support the first pinion unit, the second pinion unit, and the third pinion unit in a rotatable manner.

9. The internal hollow type rotary actuator according to claim 8, characterized in that: The virtual circle formed by the first support shaft, the second support shaft, and the third support shaft forms the same concentric circle as the rotating table. The first support shaft, the second support shaft, and the third support shaft are arranged at intervals of 120 degrees on the virtual circle. The first pinion, the second pinion, and the third pinion are gear-coupled at three positions of the ring gear at intervals of 120 degrees.

10. The internal hollow type rotary actuator according to claim 1, characterized in that: A first virtual circle formed by the rotor support, the cylindrical rotor worm wheel, the first worm, the second worm, and the third worm, and a second virtual circle formed by the first support shaft, the second support shaft, the third support shaft, and the rotating table are set with the same concentric circle as a reference.

Images