Continuous heating device for coil springs and heating method for coil springs using the same device

Abstract

Provided is a continuous heating device for coil springs and a continuous heating method for coil springs using the same. The device may include: a pair of tapered rollers configured to support and rotate the coil spring, configured to have a cross-sectional diameter that increases as it goes from the front end portion to the rear end portion, and configured to have rotational inner surfaces that are arranged to be parallel with each other while the central rotation axes thereof are not parallel with each other; a conveyor chain configured to have a push rod that is installed therein to move the coil spring; and a driving unit configured to provide a rotational driving force to the pair of tapered rollers.

Claims

1. A continuous heating device for a coil spring, the device comprising: a pair of tapered rollers configured to support and rotate the coil spring, configured to have a cross-sectional diameter that increases as it goes from a front end portion to a rear end portion, and configured to have rotational inner surfaces that are arranged to be parallel with each other while the central rotation axes thereof are not parallel with each other; an electric induction coil configured to heat the coil spring; a conveyor chain configured to have a push rod that is installed therein to move the coil spring; and a driving unit configured to provide a rotational driving force to the pair of tapered rollers.

2. The device according to claim 1, wherein upper surfaces of the pair of tapered rollers are horizontal.

3. The device according to claim 1, wherein the pair of tapered rollers are formed of a non-magnetic metal roller and a ceramic roller.

4. The device according to claim 1, further comprising a roller support shaft and an elastic buffer spring that are configured to buffer an elongation of the tapered roller in the longitudinal direction.

5. The device according to claim 1, further comprising a universal joint that is configured to effectively transfer a rotational force between a pair of driving shafts that are arranged to be parallel to then be driven in the driving unit and the pair of tapered rollers that are arranged not to be parallel.

6. The device according to claim 1, wherein the driving unit is configured to transfer a rotational driving force to two roller shaft gears by using a single power shaft gear.

7. The device according to claim 1, wherein the push rod is formed of a non-conductive ceramic material.

8. The device according to claim 1, further comprising an induction coil power controller that is configured to control an amount of electric power applied to the electric induction coil.

9. The device according to claim 1, further comprising a cooling tank that is filled with a cooling fluid to quench the coil spring.

10. A continuous heating method for a coil spring, the method comprising: inputting and rotating the coil spring by a pair of tapered rollers such that the coil spring does not pop out of the tapered rollers, the tapered rollers having a cross-sectional diameter that increases as it goes from a front end portion to a rear end portion and having rotational inner surfaces that are arranged to be parallel with each other while the central rotation axes thereof are not parallel with each other; moving the coil spring by a conveyor chain that has a push rod installed therein; and heating the coil spring by a high-frequency induced magnetic field while rotating the coil spring by using the tapered rollers in a section of an electric induction coil.

11. The method according to claim 10, further comprising dropping the heated coil spring into a cooling tank.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other aspects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

(2) FIG. 1 is a perspective view of a continuous heating device for coil springs, according to a preferred embodiment of the present invention.

(3) FIG. 2 is a view illustrating a continuous heating device for coil springs 10 when it is viewed from above.

(4) FIG. 3 is a view illustrating a continuous heating device for coil springs when it is viewed from the side.

(5) FIG. 4 is a view showing the front end portion and the rear end portion of a pair of tapered rollers 20.

(6) FIG. 5 is an enlarged view of a rear-end support shaft of the tapered roller 20.

(7) FIG. 6 is a view showing the installation state of gears that transfer a driving force from the driving unit 60 to the shaft of the tapered roller 20.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

(8) Technical terms that are used in the present specification are intended to describe only a specific embodiment, and are not intended to limit the present invention.

(9) Further, the technical terms in the specification should be construed as a meaning generally understood by those skilled in the art unless the terms are defined as another meaning and should not be construed as an excessively inclusive meaning or an excessively exclusive meaning.

(10) In addition, a singular expression used in the specification includes a plural expression as long as they are clearly distinguished in the context. In the present disclosure, the term “comprise” or “include” should not be construed as necessarily including all of various elements or various steps disclosed herein, and it should be understood that some of the elements or steps may not be included, or additional elements or steps may be further included.

(11) In addition, the same reference numeral denotes the same element throughout the present specification.

(12) Hereinafter, a continuous heating device for coil springs and a continuous heating method for coil springs using the same will be described with reference to FIGS. 1 to 6.

(13) FIG. 1 shows a continuous heating device for coil springs, according to a preferred embodiment of the present invention.

(14) In the present invention, a conveyor chain 43 is installed under a pair of rotating tapered rollers 20. The tapered rollers 20 have an input section of the coil spring 10 in the front end portion thereof and have a heating section of the coil spring 10 in the rear end portion thereof. The coil spring 10 may be rotated and moved to then be heated by an electric induction coil 31 that is installed above the heating section of the coil spring 10 of the tapered rollers 20.

(15) In the present invention, the pair of tapered rollers 20 may be shaped into a truncated cylinder that has the minimum diameter in the front end and the maximum diameter in the rear end so that the circumferential speed of the front end portion may be reduced by ½ to ⅓ of the circumferential speed of the rear end portion when the tapered roller 20 is rotated. That is, the circumferential speed may be designed such that the coil spring 10 does not pop out when the coil spring 10 is input to the front end portion (i.e., the input section of the coil spring 10) of the tapered roller 20.

(16) It is preferable to maintain the upper surface of the tapered roller 20 to be horizontal while the central rotation axis of the tapered roller 20 is tilted downwards as it goes from the front end portion to the rear end portion in order to thereby allow the coil spring 10 to horizontally move on the tapered rollers 20.

(17) The pair of tapered rollers 20 are required to be spaced a constant distance from each other in order for the coil spring 10 to move on the same. Therefore, it is preferable to install the central rotation axes of the pair of tapered rollers 20 to be spaced more in the rear end portion. Even though the diameter of the tapered roller 20 becomes larger as it goes toward the rear end portion thereof, the gap between the tapered rollers 20 may be maintained to be constant. Thus, the coil spring 10 that is placed on the pair of tapered rollers 20 may be maintained to be stable between the tapered rollers 20 without popping out of the same while moving downstream as shown in FIG. 4.

(18) The coil spring 10, which is placed on the pair of tapered rollers 20 and is rotated by the rotation of the tapered rollers 20, is transferred by the push rod 41 that is mounted on the conveyor chain 43 to pass through the electric induction coil 31. When the coil spring 10 is initially placed on the pair of tapered rollers 20, the rotational speed thereof is low. Although the rotational speed of the coil spring 10 increases as it moves toward the rear end portion, the coil spring 10 may be stable without popping out in order to thereby improve the productivity in the operation of heating the coil spring 10.

(19) The pair of tapered rollers 20 may be supported to be rotatable by means of rotational bearings that are positioned in the front end portion thereof and by means of rotational bearings that are positioned in the roller support shaft 50 that is coupled to the rear end portion of the rollers, and a rotational driving force may be supplied from the driving unit 60.

(20) The tapered roller 20 is separated into the input section of the coil spring 10 and the heating section of the coil spring 10 based on the start point of the electric induction coil 31. Preferably, the input section of the coil spring 10 may be made of a non-magnetic metal roller 21 and the heating section of the coil spring 10 may be made of a ceramic roller 22.

(21) Preferably, the non-magnetic metal roller 21 on which the coil spring 10 to be heat-treated is initially placed may be made of a metal that is hardly heated by the magnetism in order not to be easily heated by the electric induction coil 31.

(22) The electric induction coil 31 may be disposed through the entire area above the ceramic roller 22, and may heat the coil spring 10.

(23) Referring to FIG. 2 showing the continuous heating device for coil springs as viewed from above, the central rotation axes of the pair of tapered rollers 20 are not parallel with each other, and are spaced at a constant angle as it goes toward the rear end portion thereof.

(24) In addition, the cross-sectional diameter of the tapered roller 20 increases as it goes from the front end portion to the rear end portion.

(25) Since the coil spring 10 to be produced has a constant diameter, the inner surfaces of the pair of tapered rollers 20, which come in contact with the coil spring 10, may be preferably arranged to be parallel with each other.

(26) As shown in FIG. 4, the coil spring 10 may come in full contact with the pair of tapered rollers 20 at both sides of the lower portion of the coil spring 10 because the inner surfaces of the tapered rollers 20 are arranged to be parallel with each other.

(27) In addition, referring to FIG. 3 showing the continuous heating device for coil springs as viewed from the side, the central rotation axes of the pair of tapered rollers 20 are tilted downwards as it goes from the front end portion to the rear end portion while the upper surfaces of the tapered rollers 20 are maintained to be horizontal.

(28) With the structure described above, the coil spring 10 burrows further into the gap between the pair of tapered rollers 20 as it is moved by the push rod 41 from the front end portion of the roller to the rear end portion thereof.

(29) In addition, although the angular velocity of tapered roller 20 remains constant through the entire area, the diameter of the tapered roller 20 increases as the coil spring 10 moves by means of the push rod 41 from the front end portion of the roller to the rear end portion thereof so that the circumferential speed increases in order to thereby gradually elevate the rotational speed of the coil spring 10.

(30) The electric induction coil 31 is supplied with an electric power corresponding to the temperature to be heated by an induction coil power controller 33, and a water jacket may be further provided along the electric induction coil 31, through which cooling water flows to avoid an excessive increase in the temperature of the electric induction coil 31.

(31) When the coil spring is heated by the electric induction coil 31, the heat is transferred to the ceramic roller 22 that is in contact with the coil spring 10 to rotate the same so that the tapered roller 20 may be thermally expanded and the rotation axis elongates in the longitudinal direction.

(32) In order to buffer the longitudinal deformation (such as the thermal elongation or contraction of the tapered roller 20 in the axial direction), as shown in FIG. 5, the rear end portion of the tapered roller 20 is coupled to, and supported by, a roller support shaft 50, and an elastic buffer spring 51 is coupled by a nut 52 that is engaged with a thread formed on the roller support shaft 50. Thus, the central rotation axis of the tapered roller 20 may receive a rotational driving force that is generated by the driving unit 60 by being integrated with the roller support shaft 50. The fastening of the nut 52 may be reinforced by a set screw 53.

(33) Meanwhile, the central rotation axes of the pair of tapered rollers 20 may have a constant angle between the same from the front end portion of the roller to the roller support shaft 50.

(34) Although a pair of rotation shafts that generate a driving force in the driving unit 60 may be arranged to not be parallel with each other by means of a bevel gear, the driving unit 60 may be configured such that a single power shaft gear 61 drives two roller shaft gears 63 for the simplicity of design.

(35) In addition, the roller support shaft 50 may be preferably connected to the roller shaft gear 63 of the driving unit 60 by a universal joint 55 that effectively transfers a driving force even though the gear rotation shafts are at an angle therebetween.

(36) A cooling tank 71 is provided under the end portion of the tapered roller 20, which is filled with cooling oil or cooling water to quench the coil spring 10.

(37) The heating method for coil springs by using the continuous heating device for coil springs, which has the configuration described above, may be performed according to the following sequence.

(38) First, the coil spring 10 is placed on and between a pair of tapered rollers 20. Then, the push rod 41 that is installed in the conveyor chain 43 moves the coil spring 10 placed on the pair of tapered rollers 20 toward the cooling tank 71 by means of the movement of the conveyor chain 43.

(39) The conveyor chain 43 moves under the center of the pair of the tapered rollers 20. The push rod 41 mounted on the conveyor chain 43 passes through the gap between the pair of tapered rollers 20. Therefore, referring to FIG. 3, when the conveyor chain 43 moves clockwise, the coil spring 10 positioned in the center of the pair of tapered rollers 20 may be transferred by the push rod 41 from the front end portion of the roller to the rear end portion thereof.

(40) Tools for transferring the coil spring 10 are not limited to the push rod 41, and various tools may be adopted. For example, the tool may be formed to have a rough surface in order to thereby transfer the coil spring by means of a friction force with respect to the coil spring 10, or may be made in the form of a hook that may hook and transfer the coil spring 10.

(41) The push rod 41 that is mounted on the conveyor chain 43 may be preferably made of a ceramic material in order to avoid being affected by the magnetic field that is generated through a high-frequency induction of the electric induction coil 31.

(42) Meanwhile, the conveyor chain 43 that continuously moves may be preferably made of stainless steel that has a high durability.

(43) The coil spring 10 may be transferred toward the section of the electric induction coil 31 along the center of the pair of tapered rollers 20 by means of the push rod 41 mounted on the conveyor chains 43 according to the movement of the conveyor chain 43 while being rotated.

(44) Since the electric induction coil 31 has an open structure, the coil springs 10 may be continuously transferred and heated.

(45) In addition, the pair of tapered rollers 20 rotate in the same direction and the coil spring 10 is rotated between the pair of the tapered rollers 20. Thus, the coil spring 10 is rotated while being linearly moved toward the electric induction coil 31 by the push rod 41.

(46) The electrical induction coil 31 is disposed above the tapered rollers 20 to receive and heat the coil spring 10.

(47) Meanwhile, one or more electric induction coils 31 may be provided, and the electric induction coil 31 generates a magnetic field by a high-frequency induction current that is supplied from the induction coil power controller 33 in order to thereby heat the coil spring 10 in the manner of the electric induction.

(48) That is, when a current is supplied to the electric induction coil 31 by the high-frequency induction, a high-frequency induced magnetic field is generated around the electric induction coil 31 so that heat occurs in the coil spring 10 that is positioned in the range of the high-frequency induced magnetic field in order to thereby heat the coil spring 10.

(49) The coil spring 10 does not come in direct contact with the heat source in the process of heating the coil spring 10 by the electric induction, and the conductive coil spring 10 generates the heat in itself by means of the high-frequency induced magnetic field to then be heated while the coil spring 10 is rotated. Therefore, the coil spring 10 may be heated throughout the entire area thereof.

(50) In addition, the heating temperature of the coil spring 10 passing through the electric induction coil 31 may be adjusted by controlling the moving speed of the conveyor chain 43, or the heating uniformity of the coil spring 10 passing through the electric induction coil 31 may be adjusted by controlling the rotational speed of the tapered roller 20 in order to thereby produce the coil spring 10 with a high quality reliability.

(51) The coil spring 10 that has been heated by the electric induction coil 31 may be directly dropped into the cooling tank 71 in order to increase the effectiveness of the quenching.

(52) The cooling tank 71 is filled with a cooling fluid, such as water or oil, to quench the coil spring 10, and the temperature of the cooling fluid may be adjusted to a constant range by a temperature control device for the effective quenching.

(53) Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing the technical spirit or essential features thereof.

(54) Therefore, it should be understood that the embodiments described above are only examples and do not limit the present invention. The scope of the present invention described in the detailed description will be construed by the claims below, and will encompass all of changes or modifications that are derived from the meaning and range of the claims and the equivalents thereof.