JP5121270B2 - Moving quenching equipment - Google Patents

Description

  The present invention relates to a moving quenching apparatus that heats and cools an axial workpiece while moving it up and down in the axial direction.

  As a method of quenching a long shaft-like member such as a screw shaft used in a ball screw mechanism, for example, as described in Patent Document 1, the shaft-like member is rotated in a high-frequency non-oxidation quenching apparatus. While moving in the axial direction, the surface of the shaft-shaped member moved in the axial direction is heated by a high-frequency induction heating coil provided in the high-frequency non-oxidation quenching apparatus, and a coolant is sprayed onto the surface of the heated shaft-shaped member. In some cases, the surface of the shaft-like member is subjected to a quenching treatment in a non-oxidized state.

In such a device disclosed in Patent Document 1, in order to cool the screw shaft heated by the high-frequency heating coil, a cooling is provided at a position near the lower portion of the gas injection ring 4 disposed so as to surround the heating portion of the high-frequency heating coil. A cooling liquid injection ring to which a liquid introduction pipe is connected is arranged, and the cooling liquid is supplied into the cooling liquid injection ring from a number of cooling liquid injection holes formed on the inner peripheral surface of the cooling liquid injection ring, and the heating surface of the screw shaft In this case, the fuel is ejected at a required downward angle.
Japanese Patent Laid-Open No. 11-21619 (paragraph 0013, FIG. 1)

  However, since the thing of patent document 1 cools a screw axis | shaft like a shower, since a cooling fluid collides with a screw axis | shaft and reflects, cooling efficiency is bad and sufficient cooling is performed. However, there is a problem that it is necessary to increase the flow rate of the supplied coolant, and a large-capacity coolant tank is required.

  Further, when the work is a rack shaft, in the shower type as described in Patent Document 1, it is difficult for the coolant to be applied to the back side (tooth back part) of the rack teeth, and the unevenness in the tooth back part due to uneven cooling. There was a risk of occurrence. Moreover, in the case of a rack shaft or the like, the rack teeth and the heating conditions on the back side thereof are usually different. Therefore, in the method of uniformly cooling the outer periphery of the workpiece as described in Patent Document 1, the rack teeth and their There is a problem that the cooling rate on the back side becomes non-uniform, which causes a large bend in the work and makes it difficult to remove the bend in the subsequent process.

  The present invention has been made to solve the above-described conventional problems, and enables a work to be immersed in a cooling liquid filled in a cooling liquid storage chamber while being a long work. An object of the present invention is to provide a moving quenching apparatus that can cool the outer surface of a workpiece at a uniform cooling rate according to heating conditions.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that workpiece support means for supporting both ends of a shaft-like workpiece in a substantially vertical axis direction, a heating device for heating the outer surface of the workpiece, A cooling device that cools the outer surface of the workpiece heated by the heating device, and a moving device that relatively moves the cooling device and the heating device and the workpiece support means in the vertical direction along the axis of the workpiece, In the moving and quenching apparatus for heating and cooling while relatively moving the workpiece in the vertical direction, the cooling device includes a substantially annular coolant supply member that can be inserted through the workpiece, the coolant supply member, A coolant reservoir chamber formed between the workpiece and the workpiece, wherein the coolant supply member includes first and second coolant supply chambers divided into two in the circumferential direction. Coolant supply Are connected to the cooling liquid supply passages for supplying the cooling liquid, and the first and second cooling liquid supply chambers are respectively provided with injection holes for injecting the cooling liquid toward the cooling liquid storage chamber. A discharge control plate is provided at the lower end of the chamber for discharging the coolant in a limited manner through an annular gap formed between the workpiece and the chamber.

  According to a second aspect of the present invention, in the first aspect, the discharge control plate is provided with a deflection unit that deflects the flow direction of the coolant discharged from the annular gap in a direction toward the work outer surface. It is that you are.

  According to a third aspect of the present invention, in the first or second aspect, between the first and second cooling liquid supply chambers divided into two in the circumferential direction, the cooling liquid is externally provided in the lateral direction. That is, a radial gap is formed to be discharged.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the work has a rack portion in which rack teeth are formed, and the rack teeth of the rack portion and the back side thereof are Heated under different conditions by the heating device, the first and second coolant supply chambers are arranged corresponding to the rack teeth and the back side of the rack part, respectively, and the first and second coolant supply The chambers were each connected to separate coolant supply paths for supplying different flow rates of coolant.

  According to a fifth aspect of the present invention, in the fourth aspect, the ratio of flow rates ejected from the first and second coolant supply chambers is equalized between the rack teeth of the rack portion and the cooling rate on the back side. It is set as follows.

  According to the first aspect of the present invention, the substantially annular coolant supply member through which the workpiece can be inserted includes the first and second coolant supply chambers divided into two in the circumferential direction. Are connected to separate cooling liquid supply passages for supplying cooling liquids of different flow rates, and injection holes for injecting the cooling liquid toward the outer surface of the work are provided in the first and second cooling liquid supply chambers. Since a discharge control plate that restricts and discharges the coolant from the annular gap formed between the workpiece and the workpiece at the lower end of the coolant storage chamber is provided. In addition, it can be immersed and cooled in the cooling liquid filled in the cooling liquid storage chamber, so that the cooling unevenness can be suppressed and the bending generated in the workpiece can be suppressed.

  According to the second aspect of the present invention, the discharge control plate is provided with the deflecting portion that deflects the flow direction of the coolant discharged from the annular gap in the direction toward the work outer surface. The discharged coolant can be effectively applied to the outer surface of the workpiece, and the workpiece can be effectively cooled with a small amount of coolant.

  According to the third aspect of the present invention, a radial gap is formed between the first and second coolant supply chambers divided into two in the circumferential direction to discharge the coolant from the lateral direction to the outside. Therefore, the cooling liquid whose temperature has been increased by cooling the workpiece does not stay in the upper part of the cooling liquid storage chamber, and the cooling effect can be improved.

  According to the invention which concerns on Claim 4, a workpiece | work has a rack part which formed the rack tooth, The rack tooth of a rack part and its back side are heated on the conditions which differ with a heating apparatus, 1st and 2nd cooling Liquid supply chambers are arranged corresponding to the rack teeth and the back side of the rack part, respectively, and the first and second cooling liquid supply chambers are connected to separate cooling liquid supply paths for supplying different flow rates of cooling liquid, respectively. Therefore, even if the heating conditions are different between the rack teeth and the back surface side, the rack teeth and the back surface side can be cooled with a coolant having a flow rate corresponding to the heating conditions so that the cooling rate is uniform.

  According to the fifth aspect of the present invention, the ratio of the flow rates ejected from the first and second coolant supply chambers is set so that the rack teeth of the rack portion and the cooling speed on the back side are equal. Bend can be suppressed as much as possible, and the bend removal work in the post-process can be made unnecessary or simplified.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings with respect to an example in which a ball screw shaft 10 used in an electric power steering apparatus is quenched. As shown in FIG. 7, the ball screw shaft 10 has a cylindrical shaft portion 11 over the entire length in the axial direction, a ball screw groove portion 12 is formed at a substantially central portion in the axial direction, and one end in the axial direction. A rack portion 13 is formed on the top. Rack teeth 15 are formed on the rack portion 13, and both ends of the rack teeth 15 and the shaft portion 11 are connected with steps 17 and 18 as shown in FIG.

  1 and 2, reference numeral 21 denotes a main body of the moving quenching apparatus. A slider 22 is guided to the main body 21 so as to be slidable in the vertical direction, and is slid in the vertical direction by a lifting motor 23 via a ball screw mechanism 24. It has come to be. An upper support frame 25 and a lower support frame 26 are respectively installed on the upper end portion and the lower end portion of the slider 22.

  The upper support frame 25 is provided with an upper support device 28 having an upper center 27 attached to the upper end of the ball screw shaft 10 so as to be engaged with the upper end of the ball screw shaft 10 and rotatably supported. A lower center 29 that is engaged with and rotatably supported is attached.

  As shown in FIG. 3, the upper support device 28 includes a rotary shaft 31 that is supported on the upper support frame 25 so as to be rotatable around a vertical axis, and a rotation provided on the slider 22 at the upper end of the rotary shaft 31. The motor 32 is connected via a gear mechanism 33. A center shaft 34 is inserted through the rotation shaft 31, and a spline shaft 35 formed integrally with the center shaft 34 is spline-engaged with a spline sleeve 36 provided on the rotation shaft 34 so as to be slidable in the vertical direction. . The spline shaft 35 is rotatably supported by a joint 38 that is moved forward and backward by a predetermined amount by a forward / backward cylinder 37 installed on the slider 22. An upper center 27 is attached to the lower end of the center shaft 34, and a key member (not shown) that engages with a key groove (not shown) formed in the ball screw shaft 10 is attached to the upper center 27.

  As a result, the center shaft 34 to which the upper center 27 is attached is moved forward and backward by a predetermined amount by the advance / retreat cylinder 37, and is rotationally driven integrally with the rotation shaft 34 by the rotation motor 32. The ball screw shaft 10 supported along the vertical axis line between the upper center 27 and the lower center 29 is transmitted to the rotation shaft 34 through the key member, and is slid in the axial direction by the slide of the slider 22. Along the vertical direction.

  The slider 22, the lifting motor 23, the ball screw mechanism 24, and the like constitute moving means for moving the ball screw shaft 10 in the vertical direction, and the upper center 27 and the lower center 29, etc. A support means for supporting the screw shaft 10 in the vertical axis direction is configured.

  A shift stand 40 is slidably guided in the movable quenching apparatus main body 21 behind the slider 22 so as to be horizontally slidable by the shift motor 43 via the ball screw mechanism 44. ing. The shift table 40 is provided with a transformer 42 of an induction hardening unit 41. A support plate 45 made of an insulator projects from the transformer 42, and the support plate 45 extends to the axial center positions of the centers 27 and 29 through an opening 22 a that is elongated in the vertical direction formed in the slider 22. Be present. A heating device 47 for heating the outer surface of the ball screw shaft 10 is disposed on the support plate 45. As shown in FIGS. 4 and 5, the heating device 47 accommodates a high-frequency heating coil 48 having a heating portion 48 a formed in an annular shape so as to surround the ball screw shaft 10, and a heating portion 48 a of the high-frequency heating coil 48. And a heating housing 49 in which a rectangular heating chamber 49a is formed.

  The heating housing 49 is installed on the support plate 45, and the upper open end of the heating housing 49 is closed by the cover plate 50. The support plate 45 and the cover plate 50 are formed with insertion holes 45a and 50a for inserting the ball screw shaft 10 supported by the centers 27 and 29. The insertion holes 45a and 50a have diameters of the ball screw shaft 10. The inner diameter is slightly larger than that.

  The heating part 48 a of the high-frequency heating coil 48 is formed in a substantially horseshoe shape that complements the cross-sectional shape perpendicular to the axis of the rack part 13 of the ball screw shaft 10, and this horseshoe shape is large enough to pass through the ball screw shaft 10. Is formed. That is, the heating part 48a has a cylindrical part 48a1 corresponding to the shaft part 11 with an interval, and a linear part 48a2 formed in one circumferential direction of the cylindrical part 48a1 and parallel to the rack teeth 15 of the rack part 13. It is formed in the shape which connected.

  The heating chamber 49a of the heating housing 49 provided with the heating unit 48a is filled with nitrogen gas or the like injected from a gas injection device (not shown), thereby keeping the inside of the heating housing 49 in an unoxidized state. The heat treatment can be performed while preventing oxidation of the heating surface of the ball screw shaft 10.

  A cooling device 51 that rapidly cools the outer surface of the ball screw shaft 10 heated by the heating device 47 is disposed on the support plate 45 below the heating housing 49. As shown in FIG. 6, the cooling device 51 includes a substantially annular coolant supply member 52 into which the ball screw shaft 10 supported by the centers 27 and 29 can be inserted. The coolant supply member 52 is composed of coolant supply chambers 53 and 54 having two C-shapes divided into two in the circumferential direction. The two coolant supply chambers 53 and 54 are joined to each other at one end and are slightly separated from each other to form a limited radial gap 55 that opens laterally toward the outside. The inner diameter of the coolant supply member 52 is outside the ball screw shaft 10 so as to form a coolant storage chamber 57 that can be filled with a sufficient volume of coolant with the outer surface of the ball screw shaft 10. It is set considerably larger than the diameter.

  The two cooling liquid supply chambers 53 and 54, when cooling the rack portion 13, have a first cooling liquid supply chamber 53 corresponding to the rack teeth 15 and a second cooling corresponding to the back side 16 of the rack teeth 15. It functions as the liquid supply chamber 54. A plurality of injection holes 59 are opened in the inner periphery of the first coolant supply chamber 53 toward the axial center of the ball screw shaft 10, and a ball screw is provided in the inner periphery of the second coolant supply chamber 54. A plurality of injection holes 60 are opened toward the axial center of the shaft 10. The number of injection holes 59 formed in the first coolant supply chamber 53 corresponding to the rack teeth 15 is larger than the number of injection holes 60 formed in the second coolant supply chamber 54 corresponding to the back side 16. Many are formed, and more coolant can be ejected than the first coolant supply chamber 53. Separate cooling liquid supply pipes 61 and 62 are connected to the first and second cooling liquid supply chambers 53 and 54, and the first and second cooling liquids are connected via the cooling liquid supply pipes 61 and 62. The coolant is supplied to the supply chambers 53 and 54 at a predetermined flow rate ratio so that more coolant is supplied to the first coolant supply chamber 53.

  A discharge control plate 63 is attached to the lower end of the coolant supply member 51 so as to close the lower end of the coolant storage chamber 57. The discharge control plate 63 is provided with an insertion hole 63 a through which the ball screw shaft 10 is inserted, and a limited annular gap 65 is formed between the insertion hole 63 a and the outer surface of the ball screw shaft 10.

  As a result, the coolant at a predetermined flow rate supplied to the first and second coolant supply chambers 53 and 54 from the coolant supply pipes 61 and 62 is supplied to the coolant storage chamber 57 from the injection holes 59 and 60. Then, the coolant is discharged from the coolant storage chamber 57 through a radial gap 55 formed between the first and second coolant supply chambers 53 and 54.

  Here, by setting the discharge area composed of the radial gap 55 and the annular gap 65 in accordance with the supply flow rate of the cooling liquid supplied to the first and second cooling liquid supply chambers 53, 54, the coolant is stored. The cooling liquid discharged from the chamber 57 through the radial gap 55 and the annular gap 65 is restricted, and the cooling liquid storage chamber 57 can be always filled with a sufficient amount of cooling liquid. In addition, the coolant is discharged not only from below but also from the lateral direction through the radial gap 55, thereby promoting the circulation of the coolant stored in the upper portion of the coolant storage chamber 57, and the ball screw shaft. The cooling liquid whose temperature has been increased by cooling 10 is prevented from being accumulated in the cooling liquid storage chamber 57, and the cooling efficiency is improved.

  Further, as shown in FIG. 10, a chamfer 63a1 that forms a deflecting portion that deflects the flow direction of the coolant is applied to the upper portion of the insertion hole 63a of the discharge control plate 63. The chamfer 63a1 causes the chamfer 63a1 to be below the annular gap 65. By deflecting the discharged cooling liquid in a direction toward the outer surface of the ball screw shaft 10 and suppressing the cooling liquid from scattering in the radially outward direction of the ball screw shaft 10, the cooling liquid is discharged from the outer surface of the ball screw shaft 10. Thus, the cooling efficiency of the ball screw shaft 10 is improved.

  The up / down motor 23, the rotation motor 32, the shift motor 43, and the transformer 42 are connected to a control device 70 as shown in FIG. The raising / lowering motor 23, the rotation motor 32, and the shift motor 43 are controlled to be started and stopped by the control device 70, and are rotationally driven at a commanded rotation speed. Further, the transformer 42 is configured such that the output power for controlling the high-frequency heating coil 48 by the control device 70 is controlled according to the vertical position of the ball screw shaft 10.

  Next, the quenching process operation of the ball screw shaft 10 in the above configuration will be described. When the ball screw shaft 10 is attached or detached, the slider 22 is positioned at the rising end, and the upper center 27 is held at the rising end by the advancing / retreating cylinder 37 with respect to the slider 22. In this state, the ball screw shaft 10 is carried between the upper and lower centers 27 and 29 in a posture with the rack portion 13 upward, and the lower end of the ball screw shaft 10 is raised to a position penetrating the heating device 47 and the cooling device 51. The lower center 29 is engaged and supported.

  Subsequently, the upper center 27 is lowered by the advancing / retreating cylinder 37 and engaged with the upper end of the ball screw shaft 10, whereby both ends of the ball screw shaft 10 are supported in the vertical axis direction by the centers 27 and 29. At the same time, a key member (not shown) provided at the upper center 27 is engaged with the key groove of the ball screw shaft 10.

  In this state, the elevating motor 23 is driven, the slider 22 is lowered at a rapid feed speed via the ball screw mechanism 24, and the ball screw shaft 10 supported by both the centers 27 and 29 is lowered integrally with the slider 22. At the same time, nitrogen gas or the like is supplied into the heating housing 49 of the heating device 47 to make it non-oxidized. When the quenching start position (lower end) of the ball screw shaft 10 is moved to a position corresponding to the high frequency heating coil 48, the lowering operation of the slider 22 is temporarily stopped.

  Subsequently, the slider 22 starts to descend at a relatively low speed by the elevating motor 23, and the rotating motor 32 is driven so that the ball screw shaft 10 rotates about the vertical axis about the centers 27 and 29. Is done. Thereby, the ball screw shaft 10 is fed into the heating device 47 and the cooling device 51 while being rotated.

  At this time, the control device 70 controls the transformer 42 so that a predetermined output power is supplied to the high-frequency heating coil 48 at a predetermined frequency (for example, 100 kHz), and the shaft portion 11 at the lower end of the ball screw shaft 10 is The high-frequency heating coil 48 is intruded, and the outer surface of the shaft portion 11 is heated to a predetermined temperature (for example, 900 ° C.) in a non-oxidized state. The shaft portion 11 heated to a predetermined temperature by the heating device 47 is then transferred to the cooling device 51, immersed in the cooling liquid filled in the cooling liquid storage chamber 57, and cooled. Thereby, a hardened layer having a predetermined hardness and a predetermined depth is formed on the outer surface of the shaft portion 11 of the ball screw shaft 10.

  Since the shaft portion 11 is heated while the ball screw shaft 10 rotates, the outer surface of the shaft portion 11 is evenly heated even if the high-frequency heating coil 48 has a substantially horseshoe shape. The outer surface of the shaft portion 11 is evenly cooled even when different flow rates of coolant are supplied from the injection holes 59 and 60 of the first and second coolant supply chambers 53 and 54 in 51.

  In this way, the shaft portion 11 on the ball screw shaft 10 is quenched, and the outer surface of the ball screw groove portion 12 is continuously heated by the heating device 47 as the ball screw shaft 10 descends, and the cooling device 51 Cooled by.

  When the ball screw shaft 10 is lowered to a predetermined position and the start end of the rack portion 13 is moved to a position approaching the high-frequency heating coil 48, the rotation motor 32 is controlled, and the ball screw shaft 10 is moved to the rack portion 13. Positioning is stopped at the angular position shown in FIG. 5 where the rack tooth 15 corresponds to the linear portion 48a2 of the heating part 48a, that is, the angular position where the rack tooth 15 complements the substantially horseshoe shape of the high-frequency heating coil 48. When the ball screw shaft 10 is lowered to a position where the high-frequency heating coil 48 corresponds to the step 17 of the rack portion 13, the shift motor 43 is driven, and the shift base 40 is moved through the ball screw mechanism 44 by a predetermined amount. Shifted. As a result, the linear portion 48 a 1 of the high-frequency heating coil 48 is shifted by a predetermined amount in a direction approaching the rack teeth 15 of the rack portion 13. At the same time, the controller 70 controls the lowering speed of the ball screw shaft 10 to a low speed and the high-frequency heating coil 48 to a preset output power.

  By such control, normally, in the step 17 portion, current intensively flows in the corner portion 17a and the start end portion of the rack tooth 15 tends to be sweetened. Due to the shifting operation in the direction approaching the teeth 15, the heating action at the ends of the rack teeth 15 is enhanced, and the rack teeth 15 are gradually heated by the decrease in the descending speed of the ball screw shaft 10. As a result, the tendency of the baking at the start end of the rack teeth 15 to be sweetened is improved, and sufficient baking is performed from the start end of the rack teeth 15. Further, since the high-frequency heating coil 48 has a substantially horseshoe shape, even if the high-frequency heating coil 48 is shifted in a direction approaching the rack teeth 15, both end corners in the circumferential direction of the rack teeth 15 are high-frequency heating coils. It is possible to prevent the occurrence of spark-out without excessively approaching 48.

  By the way, the shift operation of the high-frequency heating coil 48 in the direction approaching the rack teeth 15 increases the distance from the high-frequency heating coil 48 on the back side 16 of the rack teeth 15, which causes the back side 16 to be baked. As described above, the lowering speed of the ball screw shaft 10 is reduced and the output of the high-frequency heating coil 48 is reduced with the shift operation in the direction of approaching the rack teeth 15 of the high-frequency heating coil 48 as described above. Since the electric power is controlled, the lowering speed of the ball screw shaft 10 is reduced and the output power of the high frequency heating coil 48 is controlled so that the rear side 16 of the rack tooth 15 has a required quenching hardness and quenching depth. It is controlled so that a hardened layer can be formed.

  That is, the output of the high-frequency heating coil 48 is tuned so that the quenching hardness and quenching depth of both the rack teeth 15 and the back side 16 satisfy predetermined standard values. Will be. Specifically, the rack teeth 15 and the back side 16 have the same quenching hardness, and the depth of quenching is as shown in FIG. Quenched layers 15a and 16a having L2 are formed.

  When the high frequency heating coil 48 is shifted in a direction approaching the rack teeth 15 and the ball screw shaft 10 is moved by a small amount in a state where the lowering speed of the ball screw shaft 10 is lowered, the quenching unit 41 The transformer 42 is shifted back in a direction in which the rack teeth 15 of the rack portion 13 are separated from the high-frequency heating coil 48 via the ball screw mechanism 44 by the shift motor 43, and the high-frequency heating coil 48 is moved relative to the ball screw shaft 10. Return to original position. At the same time, the controller 70 returns the lowering speed of the ball screw shaft 10 and the output power of the high-frequency heating coil 48 to the original values, and in this state, baking of the rack teeth 15 is continued.

  The rack portion 13 heated to a predetermined temperature by the heating device 47 is transferred to the cooling device 51 as the ball screw shaft 10 is lowered, immersed in the cooling liquid filled in the cooling liquid storage chamber 57, and quenched and cooled. Is done. At this time, more cooling liquid is supplied to the first cooling liquid supply chamber 53 corresponding to the rack teeth 15 than the second cooling liquid supply chamber 54 corresponding to the back side 16, and these cooling liquids are Since the spray holes 59 and 60 are sprayed into the coolant storage chamber 57, the rack teeth 15 have a higher cooling effect than the back side 16. Thereby, even if the heating conditions are different between the rack teeth 15 and the back side 16, the rack teeth 15 and the back side 16 are cooled so that the cooling rate is uniform. As a result, the bend generated in the ball screw shaft 10 is suppressed, and the bend removing operation in the post-process can be made unnecessary or can be easily performed.

  In addition, since the rack portion 13 can be cooled by the cooling liquid filled in the cooling liquid storage chamber 57, it is cooled as if it is immersed in the cooling tank while being long in the vertical direction like the ball screw shaft 10. This makes it possible to eliminate the uneven cooling of the back of the rack teeth 15 in particular, and to eliminate the uneven hardness of the rack tooth surfaces.

  Further, since the coolant injected into the coolant storage chamber 57 is also discharged from the lateral direction through the radial gap 55, the coolant whose temperature has risen by cooling the ball screw shaft 10 is cooled. The upper part of the liquid storage chamber 57 is not blocked and the cooling effect can be improved.

  Further, when the coolant is discharged from the coolant storage chamber 57 through the annular gap 65, the coolant is deflected in the direction toward the outer surface of the ball screw shaft 10 by the chamfer 63a1 formed on the discharge control plate 63. The cooling liquid can be effectively applied to the outer surface of the ball screw shaft 10, and the ball screw shaft 10 can be effectively cooled with a small amount of the cooling liquid.

  When the ball screw shaft 10 is lowered to a position where the heating device 47 corresponds to the step 18 portion below the rack portion 13, the quenching unit 41 is moved by the shift motor 43 via the ball screw mechanism 44 as described above. Then, the high-frequency heating coil 48 is moved closer to the rack teeth 15 of the rack portion 13, and at the same time, the lowering speed of the ball screw shaft 10 is reduced and the output power of the high-frequency heating coil 48 is controlled. As a result, a quenching layer having a required quenching hardness and quenching depth is formed on both the rack teeth 15 and the back side 16 at the end portion of the rack teeth 15 similarly to the above-described start end portion. . Thereafter, the high-frequency heating coil 48 is shifted back, the lowering speed of the ball screw shaft 10 and the output of the high-frequency heating coil 48 are returned to the normal feed speed and output, and the remaining shaft portion 11 of the ball screw shaft 10 is moved. Quench processing.

  When the slider 22 is lowered to the lower end position and the quenching process is completed over the entire length of the ball screw shaft 10, the elevating motor 23 is driven in the opposite direction to the above, and the ball screw shaft 10 is raised together with the slider 22. The When the ball screw shaft 10 is raised, low-temperature tempering is performed in the heating device 47, and the surfaces of the rack portion 13 and the ball screw groove portion 12 on the ball screw shaft 10 are tempered sequentially. At this time, the frequency of the high frequency heating coil 48 is switched to a low frequency suitable for tempering.

  Using the ball screw shaft 10 that has been hardened as described above, as shown in FIG. 7, the rack teeth 15 and the rack teeth 15 When the quenching hardness and quenching depth on the back side 16 were measured, it was confirmed that both standards could be satisfied.

  In the above-described embodiment, the example of moving and quenching the ball screw shaft 10 used in the electric power steering apparatus has been described. However, the target workpiece to be moved and quenched is limited to such a ball screw shaft 10. Instead, it can be applied to a shaft-type workpiece of a kind that is hardened under different conditions in the circumferential direction, such as a rack shaft.

  In the above-described embodiment, the ball screw shaft 10 side is moved up and down along the axial direction of the ball screw shaft 10 with respect to the heating device 47 and the cooling device 51. On the other hand, the heating device 47 and the cooling device 51 may be moved in the vertical direction.

  In the embodiment described above, both the centers 27 and 29 are provided on the slider 22 so that one center 27 can be moved forward and backward for attaching and detaching the work (ball screw shaft 10). It is also possible to make the slider 22 have a double slide configuration so that the double slide can be operated in accordance with the axial length of the workpiece so as to be able to cope with different workpieces.

  In the above-described embodiment, the heating device 47 is shifted in the radial direction of the ball screw shaft 10 with respect to the ball screw shaft 10. However, the configuration of the heating device 47 is an essential part of the present invention. The present invention is not limited to the configurations described in the embodiments.

It is a front view of the moving quenching apparatus which shows embodiment of this invention. It is a side view of the moving quenching apparatus seen from the arrow 2 direction of FIG. FIG. 3 is an enlarged cross-sectional view taken along line 3-3 in FIG. 2. FIG. 3 is an enlarged cross-sectional view of a main part of FIG. 2. It is sectional drawing cut | disconnected along 5-5 line of FIG. FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. It is a figure which shows a ball screw axis | shaft. It is a figure which shows the detail of a rack part. It is a figure which shows the quenching state of a rack part. The discharge control board is shown, (A) is a top view, (B) is the 10B-10B sectional view taken on the line of FIG. 10 (A).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Ball screw shaft, 11 ... Shaft part, 12 ... Ball screw groove part, 13 ... Rack part, 15 ... Rack tooth, 16 ... Back side, 21 ... Moving grill Input device body, 22... Slider, 23... Elevating motor, 27, 29... Center, 32... Rotating motor, 37. ... quenching unit, 47 ... heating device, 48 ... high frequency heating coil, 51 ... cooling device, 52 ... coolant supply member, 53, 54 ... coolant supply chamber, 55 ... radial gap, 57 ... coolant reservoir, 59, 60 ... injection hole, 61,62 ... coolant supply line, 63 ... discharge control plate, 65 ... annular Gap, 63a1... Deflection part (chamfering).

Claims (5)

A workpiece supporting means for supporting both ends of the shaft-shaped workpiece in a substantially vertical axis direction; a heating device for heating the outer surface of the workpiece; a cooling device for cooling the outer surface of the workpiece heated by the heating device; A moving device that includes a cooling device, a moving device that relatively moves the heating device and the workpiece supporting means in the vertical direction along the axis of the workpiece, and moves the workpiece that performs heating and cooling while relatively moving the workpiece in the vertical direction. In quenching equipment,
The cooling device includes a substantially annular coolant supply member through which the workpiece can be inserted, and a coolant storage chamber formed between the coolant supply member and the workpiece, and the coolant supply member is a circle. The first and second coolant supply chambers are divided into two in the circumferential direction, and the first and second coolant supply chambers are connected to coolant supply paths for supplying the coolant, respectively. The second coolant supply chamber is provided with an injection hole for injecting the coolant toward the coolant storage chamber, and the coolant is restricted by an annular gap formed between the workpiece and the lower end of the coolant storage chamber. A moving quenching apparatus provided with a discharge control plate that discharges automatically.   The moving quenching apparatus according to claim 1, wherein the discharge control plate is provided with a deflection unit that deflects a flow direction of the cooling liquid discharged from the annular gap in a direction toward the work outer surface. .   In Claim 1 or Claim 2, a radial clearance is formed between the first and second coolant supply chambers divided into two in the circumferential direction to discharge the coolant from the lateral direction to the outside. A moving quenching device characterized in that:   In any one of Claims 1 thru | or 3, The said workpiece | work has the rack part which formed the rack tooth, The rack tooth of this rack part and its back side are heated on the conditions which differ with the said heating apparatus, The first and second cooling liquid supply chambers are arranged corresponding to the rack teeth and the back side of the rack part, respectively, and the first and second cooling liquid supply chambers supply cooling liquids of different flow rates. A moving quenching apparatus characterized in that it is connected to a separate coolant supply path.   5. The movement according to claim 4, wherein the ratio of flow rates ejected from the first and second coolant supply chambers is set so that the rack teeth of the rack portion and the cooling rate on the back side are equal. Quenching equipment.

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