WO2008096978A1

WO2008096978A1 - Vibrating rod in concrete compacting vibrator and method for fabricating the same

Info

Publication number: WO2008096978A1
Application number: PCT/KR2008/000573
Authority: WO
Inventors: Jeong Hye Park
Original assignee: Jeong Hye Park
Priority date: 2007-02-07
Filing date: 2008-01-30
Publication date: 2008-08-14
Also published as: KR100782997B1

Abstract

Vibrating rod (31 ) in a concrete compacting vibrator and a method for fabricating the same, in which a controller (39) for a BLDC motor (38) is placed in a body of the BLDC motor (38) and molded with epoxy (41 ) or the like for preventing the BLDC motor (38) from malfunctioning in advance in casting concrete of a building. To do this, a vibrating rod (31 ) in a concrete compacting vibrator, the vibrating rod having a BLDC motor (38) connected to a power supply cable (33a) and a vibrating piece (47) both rotatably mounted in a body thereof, a tap on a top (34) of the body, and a shoe (35) on a bottom of the body, for generating vibration as the vibrating piece (47) rotates following rotation of the BLDC motor (38) by power, the vibrating rod (31) includes the body of a cylindrical shape having an upper housing (32a) and a lower housing (32b) fastened with threads to each other, a closing plate (37) mounted to a bottom of the upper housing (32a) for closing the bottom of the upper housing (32a), a controller (39) in the upper housing (32a) for controlling operation of the BLDC motor (38), a tube (40) at a side of the controller (39) in the upper housing (32a) for passing of the power supply cable (33b), epoxy (41 ) surrounding the controller (39) and the tube in the upper housing (32a) as one body, a bearing housing (43) fixed to an upper portion of the lower housing (32b) for supporting an upper bearing (42), the bearing housing (43) having a cut away portion (43a) in one side for enabling the power supply cable (33b) to pass, a unitary shaft supported on an intermediate bearing (45) and a lower bearing (46) at an intermediate and lower portions of the lower housing (32b) respectively, having a rotor (38b) of the BLDC motor (38) fixed to an upper portion and supported on an upper bearing (42), and a vibrating piece (47) fastened to the shaft (44) with fastening members for generating vibration.

Description

VIBRATING ROD IN CONCRETE COMPACTING VIBRATOR AND METHOD FOR FABRICATING THE SAME

Technical Field

[1] The present invention relates to vibrators for removing bubbles from mortar in casting concrete in a process for construction of a building, and more particularly, to a vibrating rod in a concrete compacting vibrator and a method for fabricating the same, in which a controller for a BLDC motor is placed in a body of the BLDC motor and molded with epoxy or the like for preventing the BLDC motor from malfunctioning in advance.

[2]

Background Art

[3] A general process for construction of a building with concrete mortar at a construction site will be described, briefly.

[4] For maintaining an adequate strength following casting of the concrete mortar, a plurality of steel reinforcing rods are arranged in a portion the concrete is to be cast, tied with thin steel wires, and surrounded with a concrete form.

[5] Upon finishing such a concrete form installation, concrete mortar casting is performed in which the concrete mortar having cement, sand, and gravel of a proper ratio mixed with water uniformly is carried by a REMICON truck and introduced into the concrete form.

[6] After casting the concrete mortar thus, if the concrete form is removed after curing the concrete for a predetermined time period, construction of a frame of the building is finished.

[7] However, in a case the concrete mortar is cast, the numerous small bubbles in the concrete mortar before the concrete mortar carried by the REMICON truck cast in the concrete form causes significant drop of strength of the concrete to have hazard of collapse if the concrete is cured without removing the bubbles, leaving the bubble layers in concrete layers.

[8] Consequently, in the case the concrete mortar is cast, the bubbles are required to be removed without fail. The vibrator is used in this case.

[9] The vibrator applies heavy vibration to the concrete mortar at the time of casting the concrete mortar, for removing the bubbles from the mortar.

[10] FIG. 1 illustrates an example of a related art vibrator, provided with a vibrating rod 1 for applying vibration to the mortar at the time of casting the concrete mortar, and a power unit 3 coupled to the vibrating rod 1 with a hose 2 to rotate a rotary shaft in the vibrating rod 1 to generate vibration.

[11] FIG. 2 illustrates a longitudinal section of a related art vibrating rod, provided with a unitary cylindrical housing 5 connected to an end of the hose 2 having a flexible cable 4 therein, and a rotary shaft 6 supported on a bearing 7 in the housing, having one end connected to the flexible cable 4, and the other end in a state of a free end located in a head cap 8 fastened to an end of the housing 5 with screws.

[12] Accordingly, at the time of compacting the concrete mortar, if the power unit 3 is put into operation after putting the vibrating rod 1 in the mortar, the flexible cable 4 in the hose 2 rotates by the power, to rotate the rotary shaft 6 fixed at the end of the flexible cable 4.

[13] In this instance, since the rotary shaft 6 has one end connected to the flexible cable 4 and the other end in a state of a free end located in a head cap 8, the other end of the rotary shaft 6 hits an inside of the head cap 8, to generate vibration, thereby enabling to remove the bubbles from the mortar.

[14] However, the related art vibrating rod in the vibrator has the following problems.

[15] First, the vibration generated as the free end of the rotary shaft fixed to the flexible cable hits the inside of the head cap has not been adequate, resulting to have poor efficiency of removal of the bubbles from the mortar.

[16] Second, the rotation of the flexible cable in the hose following operation of the power unit, causing friction and wear, makes a lifetime of the hose short.

[17] Third, the related art vibrator is not convenient to use because the connection of the power unit and the vibrating rod with the hose causes to require that one worker carries the vibrating rod held in hands while another worker carries the heavy power unit whenever a compacting location is changed at the time of compacting the concrete mortar.

[18] Fourth, providing a long hose for solving above problem is impracticable due to twisting of the flexible hose, restricting transmission of power from the power unit to the vibrating rod.

[19] A new type of vibrator vibration rod has been developed to solve above problems, and registered as a Korean utility model No. 410704.

[20] FIG. 3 illustrates a longitudinal section of another example of a related art vibrating rod with a BLDC motor, provided with a housing divided into first, second and third housings 5a, 5b, and 5c fastened together with threads, a head cap 8 fastened to one end of the first housing with threads having a bearing 15a mounted therein to support one end of an eccentric shaft 14, and the eccentric shaft 14 supported on a bearing 15b in the first housing rotated by the BLDC motor 16 to generate the vibration.

[21] Mounted in the second housing 5b fastened to the first housing 5a with threads, there is the BLDC motor 16 having a stator 16a and a rotor 16b, with the rotor 16 fixed to a shaft 16c supported on bearings 18a and 18b, which is connected to the eccentric shaft 14 with connection means.

[22] The third housing 5c has a tap 21 fastened thereto with thread, and the tap 21 is connected to a hose 22 having a cable 19 therein.

[23] Upon application of power to the vibrator after putting the vibrating rod 1 in the concrete mortar for compacting the concrete mortar, the power is applied to the BLDC motor 16 through the cable 19 and 19a, to rotate the rotor 16b fixed to the shaft 16c at a high speed.

[24] The high speed rotation of the rotor 16b is transmitted to the eccentric shaft 14 supported on the bearings 15a and 15b through the shaft 16c, such that the eccentric shaft 14 generate vibration, thereby removing bubbles from the concrete mortar to compact the same.

[25]

Disclosure of Invention Technical Problem

[26] However, through the related art vibrating rod has an advantage in that the BLDC motor mounted in the vibrating rod without additional casing permits quick dissipation of an intensive heat from the operation, the related art vibrating rod has disadvantages as follows.

[27] First, because the controller which controls the BLDC motor in the housing is located far from the vibrating rod, to have great resistance of the cable in operation of the BLDC motor to cause malfunction of a semiconductor chip in the controller which is sensitive to the resistance, the BLCD motor becomes inoperative in the middle of compacting the concrete mortar.

[28] Second, the lengthy cable (about 7 - 8 meters) which connects the BLDC motor to the controller generates noise during operation of the BLDC motor to cause malfunction of the BLDC motor.

[29] Third, the connection of the shaft having the rotor fixed thereto and the eccentric shaft which generates the vibration with the connection means causes a power transmission loss come from machining and assembly errors, leading the vibration weak.

[30] Fourth, the machining and assembly errors of the shaft and the eccentric shaft are liable to cause failure in connection of the shaft to the eccentric shaft in a step of assembling the first, and second housings.

[31] Fifth, the cable connected to the stator of the BLDC motor left in the third housing is liable to break at a cable connection portion to the stator due to the vibration generated following the rotation of the eccentric shaft in long time use of the vibrating rod. [32]

Technical Solution

[33] To solve the problems, an object of the present invention is to provide a vibrating rod in which a controller which controls a BLDC motor is mounted to an inside of a body of the vibrating rod close to the BLDC motor and molded with epoxy for quick dissipation of heat from the controller, for preventing the BLDC motor from malfunctioning in advance.

[34] Another object of the present invention is to provide a vibrating rod in which a vibrating piece is fixed to a shaft rotated following operation of a BLDC directly, for preventing a power loss in operation of the BLDC motor.

[35] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a vibrating rod in a concrete compacting vibrator, the vibrating rod having a BLDC motor connected to a power supply cable and a vibrating piece both rotatably mounted in a body thereof, a tap on a top of the body, and a shoe on a bottom of the body, for generating vibration as the vibrating piece rotates following rotation of the BLDC motor by power, the vibrating rod includes the body of a cylindrical shape having an upper housing and a lower housing fastened with threads to each other, a closing plate mounted to a bottom of the upper housing for closing the bottom of the upper housing, a controller in the upper housing for controlling operation of the BLDC motor, a tube at a side of the controller in the upper housing for passing of the power supply cable, epoxy surrounding the controller and the tube in the upper housing as one body, a bearing housing fixed to an upper portion of the lower housing for supporting an upper bearing, the bearing housing having a cut away portion in one side for enabling the power supply cable to pass, a unitary shaft supported on an intermediate bearing and a lower bearing at an intermediate and lower portions of the lower housing respectively, having a rotor of the BLDC motor fixed to an upper portion and supported on an upper bearing, and a vibrating piece fastened to the shaft with fastening members for generating vibration.

[36] In another aspect of the present invention, a method for fabricating a vibrating rod in a concrete compacting vibrator includes the steps of forming an upper housing, a lower housing, a tap, and a shoe of the vibrating rod individually to assemble into the vibrating rod with threads, after closing a bottom with a closing plate, placing in a controller and a tube in the upper housing in succession, and molding portions excluding a portion the controller to be soldered thereto with epoxy, thereby finishing assembly of the upper housing, after placing a stator of the BLDC motor having one end of a power supply cable fixedly secured thereto in the lower housing from a top of the lower housing, placing a shaft having an intermediate bearing, a lower bearing, a rotor, and a vibrating piece secured thereto in the lower housing from a bottom thereof, and placing the bearing housing having the upper bearing secured thereto in the lower housing from a top thereof to support the top side of the shaft, thereby finishing assembly of the lower housing, assembling the upper housing and the lower housing together with threads after the power supply cable having one end connected to the stator is passed through the cut away portion in the bearing housing and an inside of the tube, soldering the other end of the power supply cable to a terminal of the controller exposed to an outside of the epoxy, and fastening the shoe to the lower housing and the tap to the upper housing. [37]

Advantageous Effects

[38] The present invention has following advantageous effects.

[39] First, since the location of the controller close to the BLDC motor molded with epoxy permits not to vary resistance of the power supply cable during operation of the BLDC motor, malfunction of the BLDC motor can be prevented in advance.

[40] Second, since the controller is close to the BLDC motor, no noise affects the BLDC motor even if the power supply cable is long (about 7 - 8 meters).

[41] Third, the direct securing of the vibrating piece to the unitary shaft fixedly secured to the rotor permits the rotating force of the BLDC motor to be transmitted to the vibrating piece as it is, thereby permitting to obtain stronger vibration.

[42] Fourth, the location of the power supply cable connected to the stator of the BLDC motor in the tube molded with the upper housing permits to prevent the cable from breaking in advance at a connection portion to the stator by the vibration from the rotation of the eccentric shaft when the vibrating rod is used for a long time.

[43]

Brief Description of the Drawings

[44] The accompanying drawings, which are included to provide further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiments of the disclosure and together with the description serve to explain the principle of the disclosure.

[45] In the drawings:

[46] FIG. 1 illustrates a perspective view of an example of a related art vibrator;

[47] FIG. 2 illustrates a longitudinal section of a related art vibrating rod;

[48] FIG. 3 illustrates a longitudinal section of another example of a related art vibrating rod with a BLDC motor;

[49] FIG. 4 illustrates a longitudinal section of a vibrating rod in accordance with a preferred embodiment of the present invention; [50] FIG. 5 illustrates a section across a line A-A in FIG. 4;

[51] FIG. 6 illustrates a section across a line B-B in FIG. 4;

[52] FIG. 7 illustrates a section across a line C-C in FIG. 4; and

[53] FIG. 8 illustrates a flow chart showing the steps of a method for fabricating a vibrating rod in accordance with a preferred embodiment of the present invention.

[54]

Best Mode for Carrying Out the Invention

[55] Reference will now be made in detail to the specific embodiments of the present invention, examples of which are illustrated in the accompanying drawings FIGS. 4 to 8. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[56] FIG. 4 illustrates a longitudinal section of a vibrating rod in accordance with a preferred embodiment of the present invention, FIG. 5 illustrates a section across a line A-A in FIG. 4, and FIG. 6 illustrates a section across a line B-B in FIG. 4.

[57] Referring to FIGS. 4 to 6, the vibrating rod 31 includes a cylindrical body 32 having an upper housing 32a and a lower housing 32b fastened with threads to each other, wherein the upper housing 32a has a tap 34 fastened thereto at a top thereof with threads for protection of a power supply cable 32a, and the lower housing 32a has a shoe 35 fastened thereto with threads at a bottom thereof.

[58] The tap 34, fastened to the upper housing 32a, is placed in the upper housing 32a, supported on a step 34a, and fastened thereto with a fastening nut 36 fastened to an outside of the upper housing 32a, to fixedly secure the tap 34 to the upper housing 32a.

[59] This is to make to rotate, not the tap 34, but the fastening nut 36 only, in a process of securing the tap 34 to the upper housing 32a that supports the power supply cable 33a, for preventing the power supply cable from twisting.

[60] There are a closing plate 37 mounted to a bottom of the upper housing 32a, a controller 39 on the closing plate 37 for controlling operation of the BLDC motor 38, a tube 40 at a side of the controller 39 having a power supply cable 33b provided therein for application of power to a stator 38a of the BLDC motor 38, wherein both the controller 39 and the tube 40 are molded together with epoxy 41 which is filled in the upper housing 32a such that a portion 39a of the controller 39 power supply cables 33a and 33b are soldered thereto is exposed to an outside of the epoxy molding.

[61] The epoxy 41 is filled in the upper housing 32a such that the portion 39a the power supply cables 33a and 33b are soldered thereto is exposed to an outside of the epoxy molding, for soldering the power supply cable 33b to the controller 39 molded in the upper housing 32a in a state the upper housing 32a and the lower housing 32b are assembled together. [62] In the meantime, there are the stator 38a of the BLDC motor 38 pressed in and secured to the lower housing 32b, and a bearing housing 43 over the stator 38a for supporting an upper bearing 42, having a cut away portion 43a in one side for enabling the power supply cable 33b to pass, wherein an upper portion of a unitary shaft 44 having the rotor 38b of the BLDC motor 38 fixed thereto is placed in the upper bearing 42.

[63] There are an intermediate bearing 45 pressed in and secured to an intermediate portion of the shaft 44, a lower bearing 46 pressed in and secured to a lower portion of the shaft 44, and a vibrating piece 47 between the intermediate bearing 45 and the lower bearing 46 for generating vibration when the shaft 44 rotates.

[64] The operation of the vibrating rod of the present invention will be described.

[65] FIG. 8 illustrates a flow chart showing the steps of a method for fabricating a vibrating rod in accordance with a preferred embodiment of the present invention.

[66] Referring to FIG. 8, the vibrating rod 31 is fabricated by dividing the vibrating rod

31 into the upper housing 32a, the lower housing 32b, the tap 34, the shoe 35, and the fastening nut 36, and fastening together with threads (SlOl).

[67] After closing a bottom of the upper housing 32a with the closing plate 37, the controller 39 and the tube 40 are placed in the upper housing 32a in succession, and portions excluding the portion 39a the controller 39 to be soldered thereto are molded with epoxy 41, thereby finishing assembly of the upper housing 32a (S 102).

[68] In the meantime, after placing the stator 38a of the BLDC motor 38 having one end of the power supply cable 33b fixedly secured thereto in the lower housing 32b from a top of the lower housing 32b, the unitary shaft 44 having the intermediate bearing 45, the lower bearing 46, the rotor 38b, and the vibrating piece 47 secured thereto is placed in the lower housing 32b from the bottom thereof, and the bearing housing 43 having the upper bearing 42 pressed therein and secured thereto is placed in the lower housing 32b from the top thereof to support the top side of the shaft 44 (S 103).

[69] In this instance, the power supply cable 33b having one end soldered to the stator 38a of the BLDC motor 38 is exposed to an upper side through the cut away portion 43a in the bearing housing 43, wherein the power supply cable 33b has a length enough to fix to the soldered portion 39a of the controller 39.

[70] Because the vibrating piece 47 between the intermediate bearing 45 and the lower bearing 46 is fastened with fastening members 48 in a state a key 49 is placed in key grooves 44a and 47 a, the rotating force can be transmitted from the shaft 44 driven by the BLDC motor 38 to the vibrating piece 47 as it is without being attenuated.

[71] Though the embodiment describes in an order of assembling the lower housing 32b after assembling the upper housing 32a at first, the order of assembly is not limited to above because the order of assembly can be changed as the case demands. [72] After assembly of the upper housing 32a and the lower housing 32b by above methods, the upper housing 32a and the lower housing 32b are put together with threads, in a state the power supply cable 33b exposed through the cut away portion 43a in the bearing housing 43 is passed through an inside of the tube 40 molded with the epoxy 41 in the upper housing 32a.

[73] Though the power supply cable 33b passed through the tube 40 in the upper housing

32a is liable to be twisted in a step the upper housing 32a and the lower housing 32b are put together with threads, the upper housing 32a and the lower housing 32b can be put together with threads without twisting the power supply cable 33b because, though the length is as much as a circumference of an inside diameter of the upper housing 32a, there is a space between the upper housing 32a and the lower housing 32b, and the tube 40 has an inside diameter adequately greater than an outside diameter of the power supply cable 33b (S 104).

[74] After the upper housing 32a and the lower housing 32b are put together by above method, the power supply cable 33b passed through the tube 40 is soldered and fastened to the soldering portion 39a exposed to an outside of the controller 39 (S 105).

[75] Then, the shoe 35 is fastened to a bottom of the lower housing 32b with threads, and the tap 34 having another power supply cable 33a passed therethrough is brought to the upper housing 32a, the power supply cable 33a at one end thereof is soldered to the controller, the step 34a of the tap 34 is put close to the upper housing 32a, and the fastening nut 36 is fastened, thereby finishing assembly of the vibrating rod 31 of the present invention (S 106).

[76] Upon putting the vibrating rod 31 in the mortar and applying power by using a switch (not shown) in a state the vibrating rod 31 of the present invention is assembled by above assembly process, the power is applied to the controller 39 through the power supply cable 19 and 19a, to drive the BLDC motor 38, the vibrating piece 47 fixed to the shaft 44 rotates at a high speed.

[77] Following the high speed rotation of the shaft 44, the vibrating piece 47 also rotates at a high speed, to generate vibration owing to the eccentricity, to remove bubbles from the mortar in compacting the concrete mortar.

[78] Though heat is generated at the controller 39 in a process the BLDC motor 38 is driven with the controller 39 by supplying the power to rotate the vibrating piece 47 at the high speed, since the heat is transmitted through the epoxy 41 which molded the controller 39, to dissipate the heat to an outside of the upper housing 32a through the epoxy 41, burning of controller 39 can be prevented.

[79] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. Industrial Applicability

[80] The vibrating rod of the present invention has the following industrial applicability.

[81] First, since the location of the controller close to the BLDC motor molded with epoxy permits not to vary resistance of the power supply cable during operation of the BLDC motor, malfunction of the BLDC motor can be prevented in advance.

[82] Second, since the controller is close to the BLDC motor, no noise affects the BLDC motor even if the power supply cable is long (about 7 - 8 meters).

[83] Third, the direct securing of the vibrating piece to the unitary shaft fixedly secured to the rotor permits the rotating force of the BLDC motor to be transmitted to the vibrating piece as it is, thereby permitting to obtain stronger vibration.

[84] Fourth, the location of the power supply cable connected to the stator of the BLDC motor in the tube molded with the upper housing permits to prevent the cable from breaking in advance at a connection portion to the stator by the vibration from the rotation of the eccentric shaft when the vibrating rod is used for a long time.

Claims

[1] A vibrating rod in a concrete compacting vibrator, the vibrating rod having a

BLDC motor connected to a power supply cable and a vibrating piece both rotatably mounted in a body thereof, a tap on a top of the body, and a shoe on a bottom of the body, for generating vibration as the vibrating piece rotates following rotation of the BLDC motor by power, the vibrating rod comprising: the body of a cylindrical shape having an upper housing and a lower housing fastened with threads to each other; a closing plate mounted to a bottom of the upper housing for closing the bottom of the upper housing; a controller in the upper housing for controlling operation of the BLDC motor; a tube at a side of the controller in the upper housing for passing of the power supply cable; epoxy surrounding the controller and the tube in the upper housing as one body; a bearing housing fixed to an upper portion of the lower housing for supporting an upper bearing, the bearing housing having a cut away portion in one side for enabling the power supply cable to pass; a unitary shaft supported on an intermediate bearing and a lower bearing at an intermediate and lower portions of the lower housing respectively, having a rotor of the BLDC motor fixed to an upper portion and supported on an upper bearing; and a vibrating piece fastened to the shaft with fastening members for generating vibration.

[2] The vibrating rod as claim in claim 1, wherein the tap is placed in the upper housing, and a fastening nut is fastened to an outside of the upper housing with threads to secure the tap.

[3] The vibrating rod as claim in claim 1, wherein the shaft and the vibrating piece have key grooves respectively for placing a key therein.

[4] A method for fabricating a vibrating rod in a concrete compacting vibrator comprising the steps of: forming an upper housing, a lower housing, a tap, and a shoe of the vibrating rod individually to assemble into the vibrating rod with threads; after closing a bottom with a closing plate, placing in a controller and a tube in the upper housing in succession, and molding portions excluding a portion the controller to be soldered thereto with epoxy, thereby finishing assembly of the upper housing; after placing a stator of the BLDC motor having one end of a power supply cable fixedly secured thereto in the lower housing from a top of the lower housing, placing a shaft having an intermediate bearing, a lower bearing, a rotor, and a vibrating piece secured thereto in the lower housing from a bottom thereof, and placing the bearing housing having the upper bearing secured thereto in the lower housing from a top thereof to support the top side of the shaft, thereby finishing assembly of the lower housing; assembling the upper housing and the lower housing together with threads after the power supply cable having one end connected to the stator is passed through the cut away portion in the bearing housing and an inside of the tube; soldering the other end of the power supply cable to a terminal of the controller exposed to an outside of the epoxy; and fastening the shoe to the lower housing and the tap to the upper housing.