JP5447330B2 - Induction hardening equipment - Google Patents

Description

  The present invention relates to an induction hardening apparatus that performs induction hardening on an outer diameter surface of a shaft portion of a shaft member such as a rear axle shaft used in a vehicle.

  A shaft-like member such as a rear axle shaft used in a vehicle may be subjected to a quenching process in order to increase hardness. The quenching process is a heat treatment in which the steel is heated to an austenite structure and then rapidly cooled in water or oil to change the martensite structure. The shaft-shaped member may be subjected to induction hardening. Induction hardening is a method of heat treatment that causes electromagnetic induction by high-frequency electromagnetic waves in metal and heats the surface to quench, forming a hardened layer by hardening only the metal surface, and the inside is tough By maintaining the original state of maintaining the material, it is possible to make the material rich in flexibility.

In the induction hardening process for a shaft-like member such as a rear axle shaft, the shaft-like member is surrounded by a coil and a high-frequency current is passed through the coil. By flowing a high-frequency current through the coil in this way, electromagnetic induction occurs and an induced current due to the high-frequency magnetic flux flows on the surface of the shaft member. When the induced current flows, energy is lost due to the electric resistance of the shaft-shaped member, and heat is generated. Then, when the surface of the shaft-shaped member has risen to a predetermined temperature, the heating is stopped, and the induction hardening process is completed by quenching by spraying water.
Such an induction hardening apparatus for a shaft-like member such as a rear axle shaft is disclosed in Patent Document 1, for example.

FIG. 1 is a schematic view of a conventional induction hardening apparatus for a rear axle shaft.
In FIG. 1, the induction hardening apparatus 1 is schematically configured from an upper main shaft 2, a lower main shaft 4, a coil 10, and a quenching water bottle 12.

  The upper main shaft 2 is provided downward, and the lower main shaft 4 is rotatably attached to the main shaft base 6. The lower main shaft 4 is rotationally driven by a motor 16 controlled by the control device 14.

A rear axle shaft 8 that is a work to be induction-hardened is arranged with its axial direction up and down, and is supported by the upper main shaft 2 and the lower main shaft 4 so as to be rotatable integrally with the lower main shaft 4.
The coil 10 and the quenching water bottle 12 surround the rear axle shaft 8. The coil 10 and the quenching water bottle 12 are integrated with the quenching water bottle 12 disposed below the coil 10, and can move up and down by the control of the control device 14 while surrounding the rear axle shaft 8. It is configured. The quenching water bottle 12 is formed of an insulator such as a resin material.

  When induction hardening of the rear axle shaft 8 is performed in the induction hardening apparatus shown in FIG. 1, the rear axle shaft 8 is first supported by the upper main shaft 2 and the lower main shaft 4, and the rear axle shaft 8 is rotated by the motor 16.

  Next, the integrated unit of the coil 10 and the quenching water bottle 12 is lowered to the lowest part of the rear axle shaft 8 by the control of the control device 14. And while raising the integrated object of the coil 10 and the quenching water cylinder 12 upwards by control of the control apparatus 14, while supplying a high frequency current to the coil 10, a cooling water is supplied toward the rear axle shaft 8 from the quenching water cylinder 12. .

  Electromagnetic induction occurs when a high-frequency current flows through the coil 10, and an induced current due to a high-frequency magnetic flux flows on the surface of the rear axle shaft 8. Energy is lost due to the electrical resistance of the rear axle shaft 8 due to the flow of the induced current. Will occur. As described above, since the coil 10 moves upward, the induced current stops at a certain height position of the rear axle shaft 8 for a certain period of time. The fixed time can be adjusted by the moving speed of the coil 10 upward, and the moving speed is such that the induced current flows for the time that the surface temperature of the rear axle shaft 8 rises to a desired predetermined temperature by the flow of the induced current. Adjust as follows.

  Since the coil 10 and the quenching water bottle 12 are integrated as described above, the surface temperature of the rear axle shaft 8 is increased by causing an induction current to flow on the surface of the rear axle shaft 8 by passing a high frequency current through the coil 10. Then, cooling water is supplied to the position by the quenching water bottle 12 and rapidly cooled, and the induction hardening process is completed.

FIG. 4 is an enlarged view of part A in FIG.
As described above, when induction hardening is performed by the induction hardening apparatus 1, it is necessary to lower the integrated body of the coil 10 and the quenching water bottle 12 to the lowermost part of the rear axle shaft 8. At this time, for example, a human error of an abnormal operation due to an error input to the control device 14 by an operator, an abnormality of the control device 14, or a speed at which the integrated object is lowered is too fast, and the control device 14 performs stop control of the integrated object. In some cases, the integrated object may move to a position lower than the lowermost part of the rear axle shaft 8 due to reasons such as not being in time. In this case, the bottom surface 12a of the quenching water cylinder 12 and the upper horizontal surface 6a of the headstock 6 collide, and the quenching water bottle 12 and the headstock 6 may be damaged by the impact of the collision. In particular, in order to shorten the work time of induction hardening, the possibility is high when the integrated object is lowered by rapid feed.

  Therefore, when the shape of the periphery of the lower spindle 4 of the headstock 6 is adjusted and the integrated object of the coil 10 and the quenching water bottle 12 is lowered, the bottom surface 12a of the quenching water bottle 12 and the upper horizontal surface 6a of the headstock 6 are in contact with each other. It is conceivable that the bottom surface 10a of the coil 10 and the upper inclined surface 6b of the headstock 6 are in contact with each other at the center through portion 12c of the quenching water bottle 12 before the operation. This is because the state of the current flowing through the coil 10 changes when the coil 10 comes into contact with the upper inclined surface 6b of the headstock 6 having conductivity, so that the coil 10 changes the state of the upper inclined surface of the headstock 6 due to the change in the state. This is a function that can detect contact with 6b (coil touch) and is called a coil touch detection function. By providing a coil touch detection function, when the coil touch is detected, the lowering of the integrated object is stopped urgently, so that the bottom surface 12a of the quenching water bottle 12 and the upper horizontal surface 6a of the headstock 6 are brought into contact in advance. It is something to prevent.

JP 2001-262230 A

  However, in the conventional induction hardening apparatus shown in FIG. 4, even when the coil touch function is added as described above, the descending of the integrated body of the coil 10 and the quenching water bottle 12 is urgently stopped by detecting the coil touch. However, there is a possibility that the integrated object further descends due to braking loss and the bottom surface 12a of the quenching water bottle 12 collides with the upper horizontal surface 6a of the headstock 6 to be damaged.

  Therefore, in view of the problems of the prior art, the present invention has a metal shaft-like member such as a rear axle shaft arranged in the vertical direction, and a support member that supports the upper and lower sides of the shaft-like member, and the shaft-like member. And a cooling water supply means capable of supplying cooling water to the member integrated with the coil, and the coil and the cooling water supply means are integrated. In an induction hardening apparatus configured to be able to move an object in a vertical direction along the axial direction while surrounding the member, a support member that supports the integrated object and the shaft-like member downward when the integrated object is lowered. An object of the present invention is to provide an induction hardening apparatus that can reduce the possibility of breakage due to a collision.

  In order to solve the above problems, in the present invention, in the induction hardening apparatus that performs induction hardening on the outer diameter surface of the shaft portion with respect to the metallic shaft-like member, the axial direction is arranged vertically. An upper main shaft that supports the upper portion of the shaft-shaped member, a lower main shaft that is supported upward by the headstock and supports the lower portion of the shaft-shaped member, and a coil that surrounds the shaft-shaped member and allows high-frequency current to flow And a cooling water supply means integrated with the coil and capable of supplying cooling water to the shaft-shaped member, wherein the coil and the cooling water supply means are integrated with each other so that the coil surrounds the shaft-shaped member. It is configured to be movable in the vertical direction as it is, and an elastic body having conductivity is provided on the headstock at a position where it can come into contact with the coil when the integrated body is lowered.

  As a result, when the integrated body is lowered, the bottom surface of the coil comes into contact with the top surface of the elastic body. Since the elastic body has conductivity, the state of the current flowing through the coil changes due to the contact, so that it can be detected that the coil and the elastic body are in contact (coil touch) due to the change in the state. By detecting the coil touch, it is possible to accurately determine the timing for preventing further lowering of the integrated object such as performing control for stopping the downward movement of the integrated object.

Further, even if control for stopping the lowering of the one-piece object is performed, the one-piece object continues to descend while reducing the lowering speed due to braking loss, but the elastic body cushions the impact caused by the collision between the coil and the elastic body. A force in a direction opposite to the lowering of the monolith is applied to the monolith. Accordingly, the presence of the elastic body can promote a decrease in the descending speed of the integrated object after the coil touch.
Therefore, it is possible to reduce the possibility of damage due to a collision between the integrated body and the support member (lower spindle, headstock) that supports the shaft-shaped member below when the integrated body is lowered.

Moreover, the said cooling water supply means surrounds the said shaft-shaped member, It is good to integrate with the said coil in the lower part of the said coil, and to form the said integrated object.
Thereby, since a coil and a cooling water supply means can be manufactured separately, and can be integrated, the increase in manufacturing cost can be suppressed.

The elastic body may be disposed on the lower side in the vertical direction of the gap between the shaft-shaped member and the cooling water supply means surrounding the shaft-shaped member.
Thereby, when the said integrated object is lowered | hung, an elastic body and a coil can be made to contact reliably.

Further, the headstock has a cone-shaped portion having the lower main shaft as an apex at an upper portion thereof, and a plane portion around a bottom surface of the cone-shaped portion, and a horizontal diameter of the gap is It may be larger than the diameter of the bottom surface of the cone-shaped portion.
As a result, the position where the coil and the elastic body come into contact with each other can be secured at a high height position by lowering the integrated object, and the cooling water supply means and the headstock are in contact with the flat portion instead of the cone-shaped portion. As a result, the contact position can be secured at a low position. Therefore, a large distance from the coil touch position to the contact position between the cooling water supply means and the headstock can be secured, so that a long time from the coil touch to the contact between the cooling water supply means and the headstock can be secured.

Moreover, the distance from the upper surface of the said elastic body to the bottom face of the said coil is good in it being shorter than the distance from the said plane part to the bottom face of the said cooling water supply means.
Thereby, it can prevent that a cooling water supply means and a headstock contact before a coil touch.

The height position of the upper surface of the elastic body may be equal to or lower than the height position of the lowermost portion of the shaft-shaped member.
Thereby, it is possible to reliably perform induction hardening to the lowest part of the shaft-shaped member.

A plurality of the elastic bodies may be provided, and the plurality of elastic bodies may be arranged so as to be point-symmetric about the lower main axis.
Thereby, the impact by the collision of a coil and an elastic body can be buffered equally by a plurality of elastic bodies.
More preferably, in addition, the plurality of elastic bodies may be arranged concentrically around the lower main axis.

The shaft-like member may be supported by the upper main shaft and the lower main shaft so as to be rotatable integrally with the lower main shaft.
Thereby, the whole shaft-like member can be induction-hardened uniformly.

  Further, it may be a rear axle shaft used in a vehicle.

  According to the present invention, a metallic shaft-like member such as a rear axle shaft is disposed in the up-down direction, the support member for supporting the upper and lower sides of the shaft-like member, the shaft-like member is surrounded, and a high-frequency current is generated. A coil that can flow, and a cooling water supply means that is integrated with the coil and that can supply cooling water to the member, and the integrated body of the coil and the cooling water supply means extends along the axial direction. In the induction hardening apparatus configured to be movable while surrounding the member in the vertical direction, there is a possibility of damage due to a collision between the integrated object and the support member that supports the shaft-shaped member below when the integrated object is lowered. It is possible to provide an induction hardening apparatus capable of reducing the above.

1 is a schematic diagram of an induction hardening apparatus for a rear axle shaft according to a first embodiment, and also serves as a schematic diagram of a conventional induction hardening apparatus for a rear axle shaft according to a second embodiment. It is the A section enlarged view in FIG. 1 which concerns on Embodiment 1. FIG. FIG. 6 is an enlarged view of a part A in FIG. 1 according to the second embodiment. It is the A section enlarged view in FIG. 1 which concerns on a prior art example.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

(Embodiment 1)
FIG. 1 is a schematic view of an induction hardening apparatus for a rear axle shaft according to the first embodiment. Since the outline of the apparatus is the same as that of a conventional example, it also serves as a schematic view of a conventional induction hardening apparatus for a rear axle shaft. The description of the matters already described is omitted. FIG. 2 is an enlarged view of part A in FIG.

  2, the configuration is the same as that of the conventional example shown in FIG. 4 except that the compression spring 18 is provided and the shape of the upper surface of the headstock 6 is different. The description of the same configuration as the conventional example shown in FIG. 4 is omitted.

  On the upper surface of the headstock 6, a conical shape portion 6 c having the lower main shaft as an apex and an upper horizontal surface 6 a around the bottom surface of the conical shape portion are provided.

  The compression spring 18 is made of a conductive metal such as iron. Moreover, it can change to the compression spring 18 and can use the elastic body which has electroconductivity, for example, a metal leaf | plate spring etc. can be used.

The compression spring 18 is positioned below the central through portion 12 c of the quenching water bottle 12. That is, the integrated body of the coil 10 and the quenching water bottle 12 is disposed so as to be movable in the vertical direction with the through portion 12 c positioned on the vertical line of the compression spring 18.
The compression spring 18 is arranged such that the height position of the upper surface thereof is the same as the height position of the lower surface of the rear axle shaft 8.
In the first embodiment, the compression spring 18 is supported by the upper horizontal surface 6a via the support member 20. However, the support position of the compression spring 18 is not limited to this, and for example, the conical shape portion 6c. You may make it support to the inclined surface 6b formed in a side surface directly or via a support member. The support member 20 needs to be made of a conductive material.

  Further, the horizontal diameter c of the through portion 12c at the center of the quenching water bottle 12 is configured to be larger than the diameter d of the bottom surface of the conical shape portion 6c. Thereby, as the coil 10 and the quenching water cylinder 12 descend, the bottom surface 12a of the quenching water pipe 12 comes into contact with the upper horizontal surface 6a instead of the inclined surface 6b.

  The distance a between the bottom surface 10a of the coil 10 and the top surface of the compression spring 18 is configured to be smaller than the distance b between the bottom surface 12a of the quenching water cylinder 12 and the upper horizontal surface 6a, that is, distance a <distance b. To do.

  In the above configuration, for example, due to an abnormality of the control device 14 or a speed at which the integrated object of the coil 10 and the quenching water bottle 12 descends is too fast, stop control of the integrated object by the control device 14 is not in time, etc. An operation in the case where the integrated object is lowered too much will be described.

  When the integrated body descends, since distance c> distance d and distance a <distance b, first, the bottom surface 10a of the coil 10 and the upper surface of the compression spring 18 come into contact with each other. Since the compression spring 18 and the support member 20 are made of conductive metal, the state of the current flowing through the coil 10 changes due to the contact. Therefore, the control device 14 causes the coil 10 to compress the compression spring 18 due to the change in the state. Detects contact with (coil touch).

Upon detection of the coil touch, the control device 14 performs control to stop the descent of the integrated object. Even with this control, the monolithic object continues to descend while decreasing the descending speed due to braking loss. However, since the compression spring 18 is an elastic body, the impact due to the collision between the coil 10 and the compression spring 18 is buffered, and a force in the direction opposite to the downward movement of the integral body is applied to the integral body. Accordingly, the presence of the compression spring 18 promotes a decrease in the descending speed of the integrated object after the coil touch.
Thereby, the time from the coil touch to the drop of the integrated object and the descending distance of the integrated object can be kept small.

  Therefore, according to the first embodiment, the bottom surface 12a of the quenching water bottle 12 and the upper horizontal surface 6a of the headstock 6 come into contact with each other at a slower descending speed of the monolith, and the bottom surface 12a of the quenching water bottle 12 and The possibility of breakage due to collision with the upper horizontal surface 6a of the headstock 6 can be reduced.

  Further, since the height position of the upper surface of the compression spring 18 is set to the same height as the lower surface of the rear axle shaft 8, it is possible to reliably perform the quenching process up to the lowermost portion of the rear axle shaft 8. Note that the height position of the upper surface of the compression spring 18 may be lower than the height position of the lower surface of the rear axle shaft 8, and the same can be said in this case.

  The distance a between the bottom surface 10a of the coil 10 and the top surface of the compression spring 18 is configured to be smaller than the distance b between the bottom surface 12a of the quenching water cylinder 12 and the upper horizontal surface 6a, that is, distance a <distance b. doing. Therefore, when the integrated body is lowered, the bottom surface 12a of the quenching water bottle 12 and the upper horizontal surface 6a are prevented from colliding before the bottom surface 10a of the coil 10 comes into contact with the compression spring 18, that is, before the coil touch is detected. it can.

  In the first embodiment, only one compression spring 18 is provided, but a plurality of compression springs 18 may be provided. When a plurality of compression springs 18 are provided, they are preferably arranged so as to be point-symmetric about the lower main shaft 4, and more preferably arranged concentrically around the lower main shaft 4. Thereby, the impact caused by the collision between the coil 10 and the compression spring 18 can be evenly buffered by the plurality of compression springs.

(Embodiment 2)
In the second embodiment, since the outline of the induction hardening apparatus is the same as that of the first embodiment, FIG. 1, which is a schematic diagram of the induction hardening apparatus for the rear axle shaft of the first embodiment, is also applied to the second embodiment. . FIG. 3 is an enlarged view of a portion A in FIG.

In the second embodiment, the rear axle shaft 8 is supported on the induction hardening apparatus 1 upside down from the first embodiment.
As shown in FIG. 3, in the second embodiment, the rear axle shaft 8 is supported by the lower main shaft 4, and the rear axle shaft 8 is formed by the clip portion 6 c provided in the vicinity of the outer peripheral portion of the main shaft base 6 and the main body of the main shaft base 6. It is sandwiched and supported.
The compression spring 18 is disposed on the clip portion 6c.

  Further, as shown in FIG. 2, in the second embodiment, the quenching water bottle 12 is included in the coil 10 and integrated.

  In the above configuration, for example, due to an abnormality of the control device 14 or a speed at which the integrated object of the coil 10 and the quenching water bottle 12 descends is too fast, stop control of the integrated object by the control device 14 is not in time, etc. An operation in the case where the integrated object is lowered too much will be described.

  As the integrated body descends, the bottom surface 10a of the coil 10 and the top surface of the compression spring 18 come into contact with each other. Since the compression spring 18 is made of a conductive metal, the state of the current flowing through the coil 10 changes due to the contact. Therefore, the control device 14 causes the coil 10 to come into contact with the compression spring 18 (the coil Detects touch.

Upon detection of the coil touch, the control device 14 performs control to stop the descent of the integrated object. Even with this control, the monolithic object continues to descend while decreasing the descending speed due to braking loss. However, since the compression spring 18 is an elastic body, the impact due to the collision between the coil 10 and the compression spring 18 is buffered, and a force in the direction opposite to the downward movement of the integral body is applied to the integral body. Accordingly, the presence of the compression spring 18 promotes a decrease in the descending speed of the integrated object after the coil touch.
Thereby, the time from the coil touch to the drop of the integrated object and the descending distance of the integrated object can be kept small.

  Therefore, according to the second embodiment, the contact between the bottom surface 10a of the coil 10 and the clip portion 6c located on the upper part of the headstock 6 is prevented, or the slower integration with the bottom surface 10a of the coil 10 and the clip portion 6c. Contact at the descending speed of the object becomes possible. Thereby, the possibility of damage due to the collision between the bottom surface 10 of the coil 10 and the clip portion 6c can be reduced.

  A metallic shaft-like member is arranged in the vertical direction, a support member that supports the upper and lower sides of the shaft-like member, a coil that surrounds the shaft-like member and allows a high-frequency current to flow, and the coil And a cooling water supply means capable of supplying cooling water to the member, and the integrated body of the coil and the cooling water supply means can be moved along the axial direction while surrounding the member in the vertical direction. In the induction hardening apparatus configured as described above, when the integrated body is lowered, the induction hardening apparatus can be used as an induction hardening apparatus that can reduce the possibility of damage due to a collision between the integrated body and the support member that supports the shaft-like member below. can do.

DESCRIPTION OF SYMBOLS 1 Induction hardening machine 2 Upper main spindle 4 Lower main spindle 6 Main spindle base 8 Rear axle shaft 10 Coil 12 Quenching water pipe (cooling water supply means)
12c Penetration part (gap between the shaft-like member and the cooling water supply means surrounding the shaft-like member)
18 Compression spring (elastic body)

Claims (9)

In the induction hardening apparatus that performs induction hardening on the outer diameter surface of the shaft portion for the metallic shaft-shaped member,
An upper main shaft that supports an upper portion of the shaft-shaped member in which the axial direction is arranged in the vertical direction;
A lower spindle supported upward on the spindle stock and supporting the lower part of the shaft-shaped member;
A coil surrounding the shaft-shaped member and capable of flowing a high-frequency current;
A cooling water supply means integrated with the coil and capable of supplying cooling water to the shaft-shaped member;
The integrated body of the coil and the cooling water supply means is configured to be movable in the vertical direction while the coil surrounds the shaft-shaped member,
An induction hardening apparatus, wherein an elastic body having conductivity is provided on the headstock at a position where it can come into contact with the coil when the integrated body is lowered.   2. The induction hardening apparatus according to claim 1, wherein the cooling water supply means surrounds the shaft-like member and is integrated with the coil at a lower portion of the coil to form the integrated object. .   3. The induction hardening according to claim 2, wherein the elastic body is disposed on the lower side in the vertical direction of the gap between the shaft-shaped member and the cooling water supply means surrounding the shaft-shaped member. apparatus. The headstock includes a cone-shaped portion having the lower spindle as an apex at an upper portion thereof, and a plane portion around the bottom surface of the cone-shaped portion,
The induction hardening apparatus according to claim 3, wherein the horizontal diameter of the gap is larger than the diameter of the bottom surface of the cone-shaped portion.   The induction hardening apparatus according to claim 4, wherein a distance from the upper surface of the elastic body to the bottom surface of the coil is shorter than a distance from the flat portion to the bottom surface of the cooling water supply means.   The induction hardening apparatus according to claim 5, wherein a height position of the upper surface of the elastic body is equal to or lower than a height position of a lowermost portion of the shaft-like member. A plurality of the elastic bodies are provided,
The induction hardening apparatus according to claim 1, wherein the plurality of elastic bodies are arranged so as to be point-symmetric about the lower main axis.   The induction hardening apparatus according to any one of claims 1 to 7, wherein the shaft-like member is supported by the upper main shaft and the lower main shaft so as to be rotatable integrally with the lower main shaft.   The induction hardening apparatus according to any one of claims 1 to 8, wherein the shaft-shaped member is a rear axle shaft used in a vehicle.

Images