Apparatus and method for quenching steel balls

Abstract

The present invention provides a steel ball quenching apparatus and quenching method that simplify the apparatus, thereby reducing manufacturing costs and improving productivity. [Solution] The steel ball quenching apparatus 1 according to the present invention comprises a rotary table 10 having multiple through holes 14 that penetrate vertically for accommodating steel balls W arranged along the rotation direction C, a holding base 20 positioned below the rotary table 10 and holding the steel balls W within the through holes 14 with the steel balls W contained within them, a high-frequency heating coil 30 positioned along the through holes 14 of the rotary table 10 for heating the steel balls W, and a cooling unit 60 for cooling the heated steel balls W. The rotary table 10 is rotated in the rotation direction C with the steel balls contained within the through holes 14 to heat and cool the steel balls W.

Description

Technical Field

[0001] The present invention relates to a steel ball quenching apparatus and a quenching method.

Background Art

[0002] Upon induction hardening of steel balls, there is disposed a spiral high-frequency induction heating coil so as to surround the outer periphery of a metal cylindrical body formed with a plurality of slits extending radially along the radial direction, the axes of the cylindrical body and the high-frequency induction heating coil are arranged in the vertical direction, the steel ball is placed by a steel ball mounting means in the hollow portion of the cylindrical body and at the central position of the high-frequency induction heating coil, b. high-frequency power is supplied from a high-frequency power supply device to the heating coil to preheat the steel ball, c. after preheating, the steel ball is moved from the central position of the heating coil to an upper position by the steel ball mounting means, so that an upward electromagnetic force is applied to the steel ball to levitate the steel ball in the space inside the hollow portion of the cylindrical body, d. next, the power supplied to the heating coil is adjusted to levitate the steel ball in the air within a range where the center of the steel ball is located above the upper end surface of the cylindrical body and the lowest point of the steel ball does not deviate from the upper end surface of the cylindrical body, thereby performing uniform induction heating while rotating the steel ball about a horizontal axis, e. after the surface of the steel ball reaches a required quenching temperature, the power supplied to the heating coil is stopped to allow the steel ball to fall naturally, and the steel ball is received by a steel ball receiving means disposed below, f. at the position where the steel ball is received by the steel ball receiving means, the entire surface of the steel ball is uniformly quenched and cooled by a cooling means. An aerial levitation induction hardening method for steel balls is disclosed (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0004] However, the high-frequency induction hardening method described in Patent Document 1 involves moving the steel ball from the center of the heating coil to an upper position using a steel ball placement means, levitating the steel ball in the space within the hollow part of the cylindrical body, and uniform induction heating while rotating the steel ball around a horizontal axis. This method has the drawbacks of being complicated and having reduced productivity. This invention has been made in view of the above circumstances, and aims to provide a steel ball quenching apparatus and quenching method that simplifies the apparatus, thereby reducing manufacturing costs and improving productivity. [Means for solving the problem]

[0005] The steel ball quenching apparatus according to the present invention comprises a rotary table having a plurality of vertically penetrating through holes arranged along the rotational direction for accommodating steel balls, a holding base positioned below the rotary table and holding the steel balls within the through holes with the steel balls accommodated in the through holes, a high-frequency heating coil positioned along the through holes of the rotary table for heating the steel balls, and a cooling unit for cooling the heated steel balls, characterized in that the rotary table is rotated in the rotational direction with the steel balls accommodated in the through holes to heat and cool the steel balls.

[0006] Preferably, the rotary table further comprises a heating region where the high-frequency heating coil is located, a cooling region for collecting and cooling the steel balls heated in the heating region, and a storage region for inserting and housing the steel balls in the through holes, and the rotary table is configured to move circumferentially in the rotational direction, passing through the storage region, the heating region, and the cooling region in that order in succession.

[0007] When the rotary table is rotated in the rotational direction, it is preferable that the steel ball rotates within the through hole.

[0008] The high-frequency heating coil is arranged so as to sandwich the through-hole from above and below, with an upper high-frequency heating coil positioned above the through-hole along the rotation direction of the rotary table and a lower high-frequency heating coil positioned below the through-hole and below the holding base, and the holding base is preferably made of a non-magnetic material.

[0009] The method for quenching steel balls according to the present invention is characterized by inserting steel balls into the through-holes of a rotary table having multiple through-holes arranged along the rotational direction, and placing the steel balls on a holding base positioned below the rotary table to hold the steel balls in place within the through-holes, rotating the rotary table in the rotational direction to heat the steel balls with a high-frequency heating coil, and then cooling them.

[0010] When the rotary table is rotated in the rotational direction, it is preferable that the steel ball rotates within the through hole.

[0011] It is preferable that the heating by the high-frequency heating coil is performed by sandwiching the through-hole from above and below between an upper high-frequency heating coil positioned above the through-hole along the rotation direction of the rotary table and a lower high-frequency heating coil positioned below the through-hole and below the holding base made of a non-magnetic material. [Effects of the Invention]

[0012] The present invention provides a steel ball quenching apparatus and quenching method that simplify the apparatus, thereby reducing manufacturing costs and improving productivity. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a top-view conceptual diagram showing a quenching apparatus according to one embodiment of the present invention. [Figure 2] Figure 2 is a conceptual diagram of Figure 1 when it is cut along line AA. [Figure 3] Figure 3 is a conceptual diagram of Figure 1 when it is cut along the line BB. [Figure 4] Figure 4 is a conceptual diagram of Figure 1 when it is cut along the DD line. [Figure 5] Figure 5 is a conceptual diagram of Figure 1 when it is cut along the EE line. [Figure 6] Figure 6 is a conceptual diagram of Figure 1 when it is cut along the FF line. [Figure 7] Figure 7(a) is a top conceptual view showing the rotary table 10 and cylindrical body 12 of Figure 1, and Figure 7(b) is a side conceptual view of the rotary table 10 and cylindrical body 12 of Figure 1 as seen from the Y direction in Figure 7(a). [Figure 8] Figure 8(a) is a top conceptual view showing the retaining base 20 of Figure 1, and Figure 8(b) is a side conceptual view of the retaining base 20 of Figure 1 as seen from the Y direction in Figure 8(a). [Figure 9] Figure 9(a) is a top conceptual view showing the fixed base 50 of Figure 1, and Figure 9(b) is a side conceptual view of the fixed base 50 of Figure 1 as seen from the Y direction in Figure 9(a). [Modes for carrying out the invention]

[0014] A steel ball quenching apparatus according to one embodiment of the present invention will be described with reference to Figures 1 to 9. The steel ball hardening apparatus 1 according to this embodiment comprises a rotary table 10, a holding base 20, a high-frequency heating coil 30, and a cooling unit 60. The rotary table 10 has multiple through holes 14 arranged along the rotation direction C that penetrate vertically (including both the direction of the arrow indicating the Z direction in Figures 1 to 7 and the opposite direction, the same applies hereinafter) for accommodating steel balls W. The rotation direction C here refers to the rotation direction of the rotary table 10, which rotates in the XY plane (both the X and Y directions are plane directions that include both the direction of the arrow and the opposite direction in Figures 1 to 7, the same applies hereinafter) with respect to the central axis CL that extends vertically in the rotary table 10.

[0015] Specifically, the rotary table 10 is constituted by a disk-shaped flat plate as shown in Figure 7, and a plurality of cylindrical through-holes 14 penetrating in the vertical direction for accommodating the steel balls W are arranged along the rotation direction C. Further, in the central portion 10A including the central axis CL of the rotary table 10, there are provided a through-hole 16 which is circular in the XY plane direction around the central axis CL, penetrates in the vertical direction, and constitutes a connecting portion connected to the upper portion 40B1 of the rotation shaft 40B of the rotation drive unit 40 to be described later, and through-holes 19, 19 which are provided around the through-hole 16 in the central portion 10A of the rotary table 10 around the central axis CL of the through-hole 16 and constitute a plurality of screw portions Sc, Sc for fixing the connected upper portion 40B1 of the rotation shaft 40B and the central portion 10A of the rotary table 10.

[0016] The rotary table 10 is made of a non-magnetic material. The non-magnetic material as used herein refers to a material that is less likely to be magnetized by a magnetic field than a magnetic material, and includes weakly magnetic materials. Specific examples of the non-magnetic material include austenitic stainless steel, brass, phosphor bronze, aluminum alloy, and ceramics. In the present embodiment, the rotary table 10 is made of ceramics.

[0017] In the present embodiment, as shown in Figures 1 to 7, cylindrical bodies 12 are further respectively arranged in the through-holes 14 of the rotary table 10, and the steel balls W are accommodated in the hollow portion of the cylindrical body 12 arranged in the through-hole 14 penetrating in the vertical direction of the rotary table 10 (referred to simply as the inside of the cylindrical body 12 in the present invention). By arranging the cylindrical body 12 in this manner and accommodating the iron balls W inside the cylindrical body 12, when the rotary table 10 is rotated in the rotation direction C and the steel balls W are heated by the high-frequency heating coil 30 to be described later, the contact with the iron balls W can be made to occur on the inner wall of the cylindrical body 12 instead of the inner wall of the through-hole 14 of the rotary table 10. Accordingly, direct contact with the rotary table 10 can be prevented, whereby the service life of the rotary table 10 can be extended.

[0018] On the other hand, the cylindrical body 12 may not be disposed, and the steel ball W may be accommodated in the hollow portion of the through-hole 14 (in the present invention, simply referred to as the inside of the through-hole 14). In that case, since the cylindrical body 12 is not required, the number of components of the steel ball quenching apparatus can be reduced. Like the rotary table 10, the cylindrical body 12 is made of a non-magnetic material, and in the present embodiment, it is made of ceramics.

[0019] The rotary table 10 further includes a heating area HA where the high-frequency heating coil 30 is disposed, a cooling area CO for collecting and cooling the steel balls W heated in the heating area HA, and an accommodation area AC for inserting and accommodating the steel balls W into the through-holes 14. It is preferable that the rotary table 10 is configured to orbit in the rotation direction C and sequentially pass through the accommodation area AC, the heating area HA, and the cooling area CO in this order. Specifically, a cooling unit 60 to be described later is disposed in the cooling area CO. The orbital movement of the rotary table 10 is performed about the central axis CL by a rotation drive unit 40 to be described later.

[0020] In this way, by configuring the rotary table 10 to have the accommodation area AC, the heating area HA, and the cooling area CO and sequentially pass through the areas AC, HA, and CO in this order by orbital movement, a steel ball quenching apparatus capable of continuous quenching can be obtained.

[0021] The holding base 20 is disposed below the rotary table 10 (in the direction opposite to the direction of the arrow indicating the Z direction in FIGS. 1 to 6 and FIG. 8, the same applies hereinafter), and holds the steel ball W in the through-hole 14 in a state where the steel ball W is accommodated in the through-hole 14.

[0022] More specifically, as shown in Figure 8, the holding base 20 is composed of a flat plate positioned below the heating region HA, where high-frequency heating coils 30 are arranged in multiple through holes 14 that are arranged along the rotation direction C of the rotary table 10, and the storage region AC, which accommodates steel balls W inserted into the through holes 14. The central part 20A has a through hole 20A1 through which the rotation shaft 40B (including its upper part 40B1) of the rotary drive unit 40, which will be described later, passes in the vertical direction, and the cooling region CO has a drop hole 20B for dropping the steel balls W, heated in the heating region HA by the rotation of the rotary table 10, into a cooling container 60A, which will be described later, positioned below the holding base 20. Furthermore, the outer periphery 20G of the holding base 20 has through holes 29, 29 that constitute multiple screw parts Sc, Sc for fixing the outer periphery 20G to the fixing base 50, which will be described later.

[0023] The high-frequency heating coil 30 is positioned along the through hole 14 and heats the steel ball W. More specifically, the high-frequency heating coil 30 is positioned in a heating region HA along the through-holes 14 of a rotary table 10, which has multiple through-holes 14 that penetrate vertically for accommodating the steel balls W, arranged along the rotation direction C, and heats the steel balls W. The high-frequency heating coil 30 is made of pure copper.

[0024] The cooling unit 60 cools the heated steel ball W. More specifically, the cooling unit 60 is located below the drop hole 20B of the holding base 20 which is placed in the cooling region CO, and consists of a cooling container 60A that holds a coolant (polymer container, water, etc.) Lq.

[0025] The steel ball hardening apparatus 1 according to this embodiment comprises the above-described rotary table 10, holding base 20, high-frequency heating coil 30, and cooling unit 60, and heats and cools the steel ball W by rotating the rotary table 10 in the rotational direction C with the steel ball W housed in the through hole 14. Thus, since the steel ball quenching apparatus 1 according to this embodiment has the above-described configuration, there is no need for devices or methods such as those described in Patent Document 1 above, which involve levitating and rotating the steel ball in the space within the hollow part of a cylindrical body. Therefore, the steel ball quenching apparatus 1 according to this embodiment is simpler, which reduces manufacturing costs and improves productivity.

[0026] The steel ball hardening apparatus 1 according to this embodiment further comprises a rotary drive unit 40 and a fixed base 50. The rotary drive unit 40 fixes the rotary table 10 and rotates it in the rotational direction C. More specifically, the rotary drive unit 40 comprises a drive unit 40A positioned below the holding base 20 and the fixed base 50 (described later), and a rotary shaft 40B connected to the drive unit 40A, extending upward (in the direction of the arrow indicating the Z direction in Figures 1 to 9, the same applies hereinafter) from the drive unit 40A along the central axis CL of the rotary table 10 through the through hole 20A1 of the holding base 20 and the through hole 50A1 of the fixed base 50 (described later), with its upper part 40B1 connected to the through hole 16 of the rotary table 10, and fixed to the center 10A of the rotary table 10 by a plurality of screw parts Sc, Sc. The rotary drive unit 40 rotates its rotation axis 40B in the XY plane direction around its central axis CL, causing the rotary table 10 fixed to the upper part 40B1 to rotate in the rotation direction C in the XY plane.

[0027] The fixed base 50 secures the holding base 20 and the high-frequency heating coil 30. More specifically, as shown in Figure 9, the fixed base 50 is composed of a flat plate positioned below the holding base 20 and the high-frequency heating coil 30. The central part 50A has a through hole 50A1 through which the rotating shaft 40B of the rotary drive unit 40 (including its upper part 40B1) passes vertically. The cooling region CO has a drop hole 50B for dropping the steel ball W, heated in the heating region HA by the rotation of the rotary table 10, into a cooling container 60A positioned below the fixed base 50. Furthermore, the peripheral part 50S of the fixed base 50 around the through hole 50A1 has through holes 59A, 59A that constitute multiple screw parts Sc, Sc for fixing to the outer peripheral part 20G of the holding base 20. In addition, the outer peripheral part 50G of the fixed base 50 further outside the peripheral part 50S has through holes 59B, 59B that constitute multiple screw parts Sc, Sc for fixing the high-frequency heating coil 20 to the fixed base 50. The fixed base 50, like the rotary table 10 and the holding base 20, is made of a non-magnetic material, and in this embodiment, it is made of ceramics.

[0028] When the rotary table 10 is rotated in the rotation direction C, it is preferable that the steel ball W rotates within the through hole 14. In this way, the rotation of the steel ball W within the through hole 14 allows for more uniform heating by the high-frequency heating coil 30. The rotation of the steel ball W within the through hole 14 can be achieved by appropriately designing the structure, such as increasing the coefficient of friction of the surface 20C of the holding base 20 that contacts the steel ball W when it is housed in the through hole 14.

[0029] The high-frequency heating coil 30 is arranged so that the through-hole 14 is sandwiched between an upper high-frequency heating coil 30A positioned above the through-hole 14 along the rotation direction C of the rotary table 10 and a lower high-frequency heating coil 30B positioned below the through-hole 14 and below the holding base 20, and the holding base 20 is preferably made of a non-magnetic material.

[0030] More specifically, the high-frequency heating coil 30 includes a first path 30C1 extending from one first end 30C01 connected to a power supply unit (not shown) upwards from the through hole 14 of the rotary table 10 to the intermediate part HA3 of the heating region HA. It also includes a second path 30C2 extending from the first path 30C1 upwards from the through hole 14 in the rotation direction C of the rotary table 10, along the through hole 14 to the entrance part HA1 of the heating region HA.

[0031] Furthermore, the system includes a third path 30C3 extending from the second path 30C2 downwards from the through hole 14 of the rotary table 10 and the holding base 20 to the entrance portion HA1 of the heating region HA, and a fourth path 30C4 extending from the entrance portion HA1 of the heating region HA downwards from the through hole 14 of the rotary table 10 and the holding base 20, along the through hole 14, through the intermediate portion HA3 to the exit portion HA2 of the heating region HA (over the entire circumference of the heating region HA in the downward direction).

[0032] Furthermore, a fifth path 30C5 extends from the fourth path 30C4 upwards from the through hole 14 of the rotary table 10 to the outlet portion HA2 of the heating region HA. Furthermore, a sixth path 30C6 extends from the fifth path 30C5 upwards from the through hole 14 in the rotation direction C of the rotary table 10, along the through hole 14 to the first path 30C1 of the intermediate portion HA3 of the heating region HA. Furthermore, a seventh path 30C7 extends from the sixth path 30C6 to the other second end portion 30C02, which is adjacent to the first path 30C1 and connected to a power supply unit (not shown). In addition, an insulator IN is placed between the adjacent first path 30C1 and the seventh path 30C7.

[0033] In other words, the high-frequency heating coil 30 is configured in a continuous line-drawn manner, with the first path 30C1, the second path 30C2, the third path 30C3, the fourth path 30C4, the fifth path 30C5, the sixth path 30C6, and the seventh path 30C7, sandwiching the through hole 14 from above and below, and an insulator IN is placed between the adjacent first path 30C1 and the seventh path 30C7.

[0034] As described above, since the high-frequency heating coil 30 is positioned to sandwich the through hole 14 from above and below, in addition to the effects described above, the heating of the iron ball W can be accelerated, further improving productivity. Furthermore, the lower high-frequency heating coil 30B is positioned via a holding base 20, and since the holding base 20 is made of a non-magnetic material, the impact on accelerating the heating of the iron ball W can be minimized.

[0035] Furthermore, when fixing the rotary table 10 to the rotary drive unit 40, and the holding base 20 and high-frequency heating coil 30 to the fixed base 50, the rotary table 10 and the holding base 20 are fixed so that there is an air gap (width H1: see Figure 5; not shown in Figures 2 to 4 and 6). The width H1 is preferably such that, in order to hold the steel ball W in the through hole 14 and to hold the steel ball W in the through hole 14 by placing the steel ball W on the holding base 20 positioned below the rotary table 10, the rotary table 10 does not come into contact with the surface 20C of the holding base 20 when the rotary table 10 rotates in the rotation direction C, and is less than the diameter of the steel ball W (if the steel ball W is not perfectly round, it is less than the diameter of an approximated perfect circle).

[0036] With respect to the high-frequency heating coil 30, as described above, when the upper high-frequency heating coil 30A and the lower high-frequency heating coil 30B are arranged with the through hole 14 sandwiched between them, a height adjustment member 70 may be appropriately placed between the fixing base 50 that secures the holding base 20 in order to adjust the height of the lower high-frequency heating coil 30B so that it is positioned below the holding base 20. The height adjustment member 70, like the rotary table 10 and the holding base 20, is made of a non-magnetic material, and in this embodiment, it is made of ceramics.

[0037] The steel ball quenching method according to this embodiment uses a steel ball quenching apparatus as shown in Figures 1 to 9, in which steel balls W are placed into the through holes 14 of a rotary table 10, which has multiple through holes 14 arranged along the rotation direction C, and the steel balls W are placed on a holding base 20 located below the rotary table 10, thereby holding the steel balls W in a state where they are contained within the through holes 14, and the rotary table 10 is rotated in the rotation direction C to heat the steel balls W with a high-frequency heating coil 30, and then cooled.

[0038] Thus, since the steel ball heating method according to this embodiment has the above-described configuration, there is no need for devices or methods such as levitating and rotating the steel ball in the space within the hollow part of a cylindrical body, as described in Patent Document 1 above. Therefore, the steel ball quenching method according to this embodiment has a simpler apparatus, which reduces manufacturing costs and improves productivity.

[0039] When the rotary table 10 is rotated in the rotation direction C, it is preferable that the steel ball W rotates within the through hole 14. In this way, the rotation of the steel ball W within the through hole 14 allows for more uniform heating by the high-frequency heating coil 30. The rotation of the steel ball W within the through hole 14 can be achieved by appropriately designing the structure, such as increasing the coefficient of friction of the surface 20C of the holding base 20 that contacts the steel ball W when it is housed in the through hole 14.

[0040] It is preferable that heating by the high-frequency heating coil 30 is performed by sandwiching the through-hole 14 from above and below between an upper high-frequency heating coil 30A positioned above the through-hole 14 along the rotation direction C of the rotary table 10, and a lower high-frequency heating coil 30B positioned below the through-hole 14 and below the holding base 20 which is made of a non-magnetic material. As described above, since the high-frequency heating coil 30 is positioned to sandwich the through hole 14 from above and below, in addition to the effects described above, the heating of the iron ball W can be accelerated, further improving productivity. Furthermore, the lower high-frequency heating coil 30B is positioned via a holding base 20, and since the holding base 20 is made of a non-magnetic material, the impact on accelerating the heating of the iron ball W can be minimized.

[0041] The diameter of the steel ball W heated by the high-frequency heating coil 30 (or, if the steel ball W is not perfectly round, the diameter of an approximated circular ball) is, for example, 15 mm. The width H1 in the aforementioned void is, for example, 5 mm. The maximum temperature reached when heating the steel ball W in the high-frequency heating coil 30 is, for example, 1000°C, and the holding time at the maximum temperature is, for example, 5 seconds.

[0042] The vertical width T1 of the rotary table 10 and cylindrical body 12 is preferably larger than the diameter of the steel ball W heated by the high-frequency heating coil 30 (or, if the steel ball W is not perfectly round, the diameter of an approximated circular ball), for example, 20 mm. The inner diameter T2 (or approximate inner diameter if the inner diameter is not perfectly round) of the through hole 14 in the rotary table 10, or the inner diameter T3 (or approximate inner diameter if the inner diameter is not perfectly round) of the cylindrical body 12, is preferably larger than the diameter of the steel ball W heated by the high-frequency heating coil 30 (or approximate diameter if the steel ball W is not perfectly round). For example, if the diameter of the steel ball W is 15 mm, then T2 is 25 mm and T3 is 20 mm.

[0043] The outer diameter T4 of the cylindrical body 12 (or the outer diameter approximated to a perfect circle if the outer diameter is not a perfect circle) is preferably such that it has a thickness that maintains the strength of the cylindrical body 12 when the rotary table 10 is rotated in the rotational direction C and heated by the high-frequency heating coil 30. For example, if T3 is 20 mm, then T4 is, for example, 25 mm. The thickness T5 of the retaining base 20 is preferably such that it has a thickness that maintains the strength of the retaining base 20 when it is fixed to the fixed base 50. For example, it is 30 mm. The thickness T6 of the fixed base 50 is preferably such that it has a thickness that maintains the strength of the fixed base 50 when the high-frequency heating coil 30 and the retaining base 20 are fixed to it. For example, it is 30 mm.

[0044] The rotation speed of the rotary table 13 is preferably set appropriately so that when it passes through the heating region HA, it reaches the desired maximum temperature (e.g., 900°C) and the holding time of the desired maximum temperature (e.g., 5 seconds). For example, it can be set to 1 rpm. The maximum temperature reached during heating and the holding time can be achieved by appropriately setting the frequency and output of the high-frequency heating coil. For example, the frequency of the high-frequency heating coil 30 when heating the steel ball W is 25 kHz, and the output is 20 kW. The number of through holes 14 provided in the rotation direction C of the rotary table 10 can be set appropriately, for example, 30. The coolant Lq used in the cooling section 60 is, for example, pure water. The steel ball W is made of carbon steel such as SUJ2. By appropriately setting the above conditions, a uniform quenched hardening layer can be formed on the surface of the steel ball W.

[0045] It should be noted that the embodiments described above are merely examples, and the numerical values, shapes, materials, components, arrangement positions and connection configurations of the components, processing of each processing unit and their sequence shown in the embodiments are examples only and are not intended to limit the present invention. Furthermore, among the components in the embodiments described above, those components that are not described in the independent claim representing the highest-level concept will be described as optional components. [Explanation of Symbols]

[0046] 1. Steel ball quenching apparatus 10 Rotating Tables 20 Retaining base 30 High-frequency heating coil 40 Rotary drive unit 50 Fixed base 60 Cooling section

Claims

1. A rotary table having multiple through-holes arranged along the rotational direction, which penetrate vertically to accommodate steel balls, A holding base positioned below the rotating table, which holds the steel ball in the through hole with the steel ball contained in the through hole, A high-frequency heating coil is positioned along the through hole of the rotating table and heats the steel ball, The system includes a cooling section for cooling the heated steel ball, A steel ball quenching apparatus that heats and cools the steel balls by rotating the rotary table in the rotational direction while the steel balls are housed in the through holes.

2. The steel ball quenching apparatus according to claim 2, wherein the rotary table further comprises a heating region where the high-frequency heating coil is arranged, a cooling region for collecting and cooling the steel balls heated in the heating region, and a storage region for inserting and housing the steel balls in the through holes, and the rotary table is configured to move circumferentially in the rotational direction and to pass through the storage region, the heating region, and the cooling region in this order in succession.

3. The steel ball quenching apparatus according to claim 1 or 2, wherein when the rotary table is rotated in the rotational direction, the steel ball rotates within the through hole.

4. The high-frequency heating coil is arranged so as to sandwich the through-hole from above and below, with an upper high-frequency heating coil positioned above the through-hole along the rotation direction of the rotary table and a lower high-frequency heating coil positioned below the through-hole and below the holding base. The steel ball quenching apparatus according to claim 1 or 2, wherein the holding base is made of a non-magnetic material.

5. A method for quenching steel balls, comprising inserting steel balls into the through-holes of a rotary table having multiple through-holes arranged along the rotational direction, and placing the steel balls on a holding base positioned below the rotary table to hold the steel balls in place within the through-holes, rotating the rotary table in the rotational direction to heat the steel balls with a high-frequency heating coil, and then cooling them.

6. The method for quenching a steel ball according to claim 5, wherein when the rotary table is rotated in the rotational direction, the steel ball rotates within the through hole.

7. The method for quenching a steel ball according to claim 5 or 6, wherein the heating by the high-frequency heating coil is performed by sandwiching the through hole from above and below with an upper high-frequency heating coil positioned above the through hole along the rotation direction of the rotary table and a lower high-frequency heating coil positioned below the through hole and below the holding base made of a non-magnetic material.

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