JP2012087348A - Pinion gear high frequency heating treatment apparatus and heat treatment method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment apparatus and a heat treatment method of a pinion gear in which the circumference top of a screw part formed in a shaft part of a pinion gear is heated uniformly, heating spots are inhibited, and improvement in reliability of heat treatment is aimed at, further, cost reduction and miniaturization of the apparatus are aimed at.SOLUTION: The heat treatment apparatus includes: a high-frequency heating coil 61 which surrounds a shaft part 72 of a pinion gear 7 annularly; a cylindrical guide member 4 in which an axis GL of the shaft part 72 substantially coincides with an axis CL of the high-frequency heating coil 61, and which inner-fits the shaft part 72 and supports the pinion gear 7 so as to have a uniform gap 63 over the circumference in an inner circumferential surface of the high-frequency heating coil 61 and an outer peripheral surface of the shaft part 72; a gear mechanism 3 which makes the guide member 4 turn around the circumference of an axis RL of the guide member 4; a driving motor 31 which actuates a gear mechanism 3; and a controller 11 which controls the driving motor 31 and a heating device 6.

Description

  The present invention relates to a high-frequency heating device that uniformly heats the outer periphery of a screw portion formed on a shaft portion of a pinion gear and a heat treatment method therefor.

In general, a pinion gear is mounted on a differential device of a drive axle for an automobile, and is used as a power transmission member that inputs a rotational driving force from a transmission to the differential device.
As shown in FIG. 7, the pinion gear 06 includes a bevel gear portion 061 that meshes with the ring gear of the differential device, and a shaft portion 062 that is coaxial with the axis line of the bevel gear portion 061 and supports the bevel gear portion 061. Yes.
The pinion gear 06 is subjected to carburizing and quenching in a carburizing tank in order to improve wear resistance after machining, and finish processing is performed after quenching.
Carburizing and quenching is also applied to the screw portion 063 provided at the intermediate portion of the shaft portion 062 of the pinion gear 06, which is provided for assembling the pinion gear 06 to the differential device.
However, since the screw portion 063 for assembling the pinion gear 06 to the differential device is weakened by carburizing and quenching, the screw portion 063 needs to be softened.

Therefore, annealing heat treatment is performed on the screw portion 063 with the apparatus shown in FIG.
A heating coil 051 of the induction heating unit 05 of the high-frequency heating device 01 is disposed around the entire periphery of the outer peripheral portion of the screw portion 063 of the bevel gear 06.
FIG. 8 illustrates an image diagram in which the heating coil 051 surrounds the outer periphery of the screw portion 063 and is connected to the high-frequency device 055. Reference numeral 053 denotes a gap between the screw portion 063 and the insulated coated electric wire 052 of the heating coil 051. It is.

Moreover, Unexamined-Japanese-Patent No. 10-43815 (patent document 1) is disclosed as a prior art which uses a high frequency heating apparatus.
In Patent Document 1, a high-frequency heating coil is wound around the outer periphery of a welded pipe, which is a workpiece, and the front and back of the annealing heating part are held by the first guide roller and the welded pipe holding, and the annealing and straightening of the welded pipe are performed. A technique for continuously performing the above is disclosed.

Japanese Patent Laid-Open No. 10-43815

However, in the structure as shown in FIGS. 7 and 8, the heating coil 051 in FIG. 8 is separated from the screw portion 063 in the Z portion and is a branched portion. It is weaker than this part, and there is a problem that heating spots are likely to occur.
Moreover, in the method of patent document 1, the structure which attaches the pipe member of a workpiece | work to a high frequency heating coil, hold | maintains a workpiece | work with the 1st guide roller and a welded pipe holder before and behind an annealing heating part, and advances a pipe member The workpiece is only held before and after the heat treatment is performed, and in order to uniformly heat-treat the surface of the pipe member, the axis of the workpiece is aligned with the axis of the high-frequency heating coil, and the workpiece There is no disclosure up to a structure or mechanism that keeps the gap between the outer periphery and the high-frequency heating coil constant.

  Therefore, the present invention has been made to solve such problems, and the shaft core of the pinion gear is made to coincide with the shaft core of the high-frequency heating coil by the guide member and can be easily attached and detached. By rotating the pinion gear together with the member about the axis, the circumference of the screw portion formed on the shaft portion of the pinion gear is uniformly heated to prevent heating spots and improve reliability. An object of the present invention is to provide a pinion gear high-frequency heat treatment apparatus and a heat treatment method thereof that are reduced in cost and size.

  The present invention achieves such an object, and in a high-frequency heating apparatus for a pinion gear that performs heat treatment on the shaft portion of the pinion gear that has a gear portion and a shaft portion that is coaxial with and integrally formed with the axis of the gear portion. A heating device having a high-frequency heating coil that annularly surrounds the shaft portion; a first axis of the gear portion substantially coincides with a second axis of the annular high-frequency heating coil; A cylindrical guide member that internally fits the shaft portion to support the pinion gear so as to have a uniform gap over the entire circumference between the peripheral surface and the outer peripheral surface of the shaft portion, and is coupled to the guide member. A driving mechanism for rotating the member around the second axis; a driving motor for driving the driving mechanism; and a control device for controlling driving of the driving motor and heating conditions of the heating device. Special To.

According to this invention, the first axis of the gear and the second axis of the annular high-frequency heating coil are made to substantially coincide with each other at the guide member, and the entire pinion gear is rotated around the second axis. The entire circumference of the shaft portion is heated evenly, and the heat treatment quality of the shaft portion is stabilized.
In addition, by fitting the shaft portion inside the cylindrical guide member, the pinion gear is supported so that there is a uniform gap over the entire circumference between the inner peripheral surface of the annular high-frequency heating coil and the outer peripheral surface of the shaft portion. Therefore, the pinion gear can be easily attached to and detached from the high-frequency heating device, and workability is improved.
Furthermore, since it is a cylindrical guide member, the shaft portion is supported over a certain length in the axial direction, so that the support of the pinion gear is stabilized.

  Preferably, in the present invention, a plurality of the guide members are arranged, and among the gears constituting the drive mechanism, the driven gears connected to the guide members are engaged with each other to generate a rotational driving force. A structure for transmitting to the plurality of guide members may be used.

  With such a configuration, a plurality of guide members are arranged and can be rotated in conjunction with each other, so that a plurality of pinion gears can be heat-treated at the same time, thereby improving work efficiency and being connected to the guide members. Since the driven gears are engaged with each other and the rotational driving force is transmitted to the guide member, the gear mechanism can be simplified, the entire apparatus can be made compact, and the cost of the entire apparatus can be suppressed.

  In the present invention, preferably, a rotation sensor for detecting the rotation of the shaft portion may be disposed to face a spline shaft forming portion provided in the shaft portion.

  With such a configuration, whether or not the pinion gear, which is the workpiece to be heated fitted in the guide member, has slipped with respect to the rotation of the guide member, is determined not by the rotation of the motor of the drive source but by the rotation of the workpiece. By detecting rotation directly and judging whether it is rotating normally, heating spots of high-frequency heating are prevented.

  Preferably, in the invention of the present application, the control device includes preheating means for controlling preheating in order to perform an annealing process of the shaft portion on which the high-frequency heating coil is disposed, on the pinion gear subjected to the quenching process. It is preferable to provide a cooling means for controlling the standing time for reducing the temperature difference between the surface and the intermediate layer portion by the heat due to the preheating and a heating means for performing the main heating.

  With such a configuration, after the processing by the preheating means for preheating, a cooling means for controlling the standing time for preheating to reduce the temperature difference between the surface and the intermediate layer is provided, so that the surface is heated excessively. It can prevent and unevenness of annealing treatment can be prevented.

  Further, in the high frequency heat treatment method for a pinion gear according to the present invention, the hardened pinion gear is supported on the guide member, a preheating step in which the high frequency heating coil is energized and preheated, and then allowed to cool for a predetermined time. An annealing process is performed on the shaft portion of the pinion gear after quenching, including a cooling process and a heating process in which the high-frequency heating coil is energized for a certain period of time and then the main heating is performed. It is characterized by performing.

In such a method invention, it is possible to carry out an annealing process that can prevent the surface from being excessively heated and prevent unevenness of the annealing process, as described in the apparatus invention.
As a result, it is possible to uniformly heat the circumference of the screw portion formed on the shaft portion of the pinion gear that performs heat treatment on the shaft portion of the pinion gear, thereby preventing heating spots and improving reliability.

According to the present invention, the first axis of the gear and the second axis of the annular high-frequency heating coil can be easily made to substantially coincide with each other by the guide member, and the heating spots are easily eliminated. This makes the heat treatment quality of the gear stable.
In addition, since the driven gear for rotation driving is directly connected to the guide member, the structure of the driving device can be simplified, and the cost and size of the device can be reduced.

The block diagram of the whole high frequency heating apparatus structure based on embodiment of this invention is shown. The schematic plane arrangement drawing of the high frequency heating device concerning the embodiment of the present invention is shown. The schematic sectional drawing in alignment with the AA of FIG. 2 is shown. The external view of the pinion gear implemented by this invention is shown. The energization circuit image figure of the cyclic | annular high frequency heating coil of this invention is shown. It is a timing chart which shows the procedure of the heat processing based on embodiment of this invention. 1 shows a schematic diagram of a prior art high-frequency heating apparatus. The energization circuit image figure of the cyclic | annular high frequency heating coil of the high frequency heating apparatus in a prior art is shown.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this example are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Only.

FIG. 1 is a block diagram showing an overall configuration according to an embodiment of the present invention, in which a high-frequency heating device 1, an optical sensor 9 that detects whether or not a pinion gear 7 is mounted on the high-frequency heating device 1, and a high-frequency annealing process. The rotation sensor 8 detects whether or not the pinion gear 7 is rotating, the optical sensor 10 that detects whether or not an operator has entered the area, and the control device 11 that controls these devices. Yes.
Further, the control device 11 controls the rotation speed, heating temperature, heating procedure, and the like of the pinion gear 7.

  As shown in FIG. 4, the pinion gear 7 to which the present invention is applied includes a bevel gear 71 having a bevel-shaped gear shape, a first axis GL of the bevel gear 71, and a coaxial line on the first bend gear 71 side from the first side The shaft portion 75, the second shaft portion 76 having a smaller diameter than the first shaft portion 75 with a distance from the first shaft portion 75, the screw portion 73 having an outer diameter smaller than the second shaft portion 76, and the screw portion 73. A spline shaft portion 74 is sequentially formed to transmit the vehicle driving force from the transmission (not shown) to the differential device.

FIG. 2 is a plan view showing the entire high-frequency heating device according to the embodiment of the present invention, and FIG. 3 is a schematic cross-sectional view taken along the line AA of FIG.
The high frequency heating apparatus 1 has a mounting base 21 mounted on a base 2. The mount 21 is provided with a first guide member 4 and a second guide member 5 for making the axis GL (see FIG. 4) of the pinion gear 7 substantially coincide with the second axis CL of the heating coil 61 of the heating device 6 described later. It is installed. (Hereinafter, since the first guide member 4 and the second guide member 5 have the same shape, only the guide member 4 is used in the description of the structure.) The guide member 4 is an outer periphery of the guide sleeve 41 fixed to the mounting base 21 and the guide member 4. Is inserted through a ball bearing 42 so as to be rotatable about the axis RL of the guide member 4.

The first guide member 4 has a first guide portion 43 into which the first shaft portion 75 of the pinion gear 7 is fitted, and is spaced from the first guide portion 43 in the axial direction and has a diameter smaller than that of the first shaft portion 75. A second guide portion 45 into which the two shaft portions are fitted is formed.
A third guide part 44 formed in a tapered shape is provided between the first guide part 43 and the second guide part 45. The first guide portion 43, the second guide portion 45, and the third guide portion 44 are formed on the same axis RL.
Therefore, the shaft portion 72 of the pinion gear 7 is easily aligned with the axis of the guide member 4 by the first guide portion 43 and the second guide portion 45.
Further, since the third guide portion 44 between the first guide portion 43 and the second guide portion 45 is formed in a tapered shape, the shaft portion 72 of the pinion gear 7 is inserted when the pinion gear 7 is fitted into the guide member 4. Since the leading end of the guide member 4 is smoothly guided and inserted through the inner wall surface of the guide member 4, the mounting operation is facilitated.

Reference numeral 6 denotes a heating device, which is arranged so that the heating coil 61 fits around the outer periphery of the threaded portion 73 of the pinion gear.
As shown in FIG. 5, the heating coil 61 is disposed along the periphery of the screw portions 73 of the two pinion gears 7 so as to show an image structure of the positional relationship between the heating coil 61 and the screw portion 73. The heating coil 61 forms the insulation-coated electric wire 62 in a coil shape, the screw portion 73 is positioned in the coil-shaped space portion, and the outer periphery of the screw portion 73 and the insulation-coated electric wire 62 are spaced at regular intervals over the entire circumference. Have.
The heating coil 61 is routed from the high frequency device 65 along the periphery of the screw portion 73, and returns to the high frequency device 65.
When a high frequency current is passed through the heating coil 61, a high frequency magnetic flux is generated in the heating coil 61, and the outer periphery of the screw portion 73 is heated by the induction action of the high frequency magnetic flux.
The axis CL of the heating coil 61 is set so as to be coaxial with the axis RL of the guide member 4 and the axis GL of the pinion gear 7.
In FIG. 5, the number of simultaneous heat treatments is two. However, when the number is increased, for example, the heating coil 61 of FIG. That's fine.

The heating coil 61 is attached to the stay 22 via the electrical insulating plate 23. Furthermore, the stay 22 is fixed to the base 2 via an electrical insulating plate 24.
Therefore, the heating coil 61 is provided with a double electrical insulation structure between the heating coil 61 and the base 2.

  A gear mechanism 3 is a drive mechanism, which is engaged with the drive gear 32 connected to the output shaft of the drive motor 31, the idler gear 33 that meshes with the drive gear 32 and rotates around the support shaft 37, and the idler gear 33. A first driven gear 34 that fits on the upper portion of the first guide member 4 and rotates the first guide member 4 about the axis RL of the first guide member 4, meshes with the first driven gear 34, and a second guide The second driven gear 35 is fitted on the upper portion of the member 5 and rotates the second guide member 5 about the axis RL of the second guide member 5.

The drive motor 31 includes a reduction mechanism (not shown) that decelerates the number of rotations of the motor and outputs it from the output shaft, and a brake device that stops the rotation at an early stage.
The drive motor 31 is attached to the upper surface of the gear case 36 mounted on the support base 25 fixed to the base 2, and the output shaft protrudes into the gear case 36, and the drive gear 32 is provided at the tip of the output shaft. Is fixed.
The idler gear 33 is fixed to the upper surface of the gear case 36 and is supported by a support shaft 37 extending into the gear case 36 via a ball bearing 38 so as to be rotatable about the support shaft 37.
The first guide member 4 in which the first driven gear 34 is externally fitted is arranged on the inner race upper surface of the ball bearing 42 interposed between the first guide member 4 and the guide sleeve 41. A flange portion 47 extending outward from the outer peripheral portion of the first guide member 4 is placed, and the first guide member 4 is rotatable about the axis RL of the first guide member 4 together with the inner race.
The first driven gear 34 is fitted on the outer periphery of the first guide member 4 and is mounted on the upper surface of the flange portion 47. The first driven gear 34 and the flange portion 47 are connected by bolts 39. It is fixed.
Since the coupling structure of the second driven gear 35 and the second guide member 5 is the same as that of the first driven gear 34, the description thereof is omitted.
In this embodiment, the rotational speed of the driven gear (guide member) is 45 to 55 RPM by the control device 11, but may be appropriately adjusted depending on the output of the heating device, the required specification and material of annealing.

  A cover 27 having holes for fitting the upper end edges of the first and second guide members 4 and 5 is fastened to the upper surfaces of the first driven gear 34 and the second driven gear 35 by bolts 28 (see FIG. 2). Yes.

Further, when the pinion gear 7 is fitted in the normal positions of the first and second guide members 4 and 5, the rotation sensors 8 and 8 are disposed so as to face the portion where the spline shaft portion 74 of the pinion gear 7 is located. .
Using the tooth profile of the spline shaft portion 74, it is detected whether the pinion gear 7 is rotating together with the first and second guide members 4 and 5, and the occurrence of unevenness in the heating temperature is prevented and heat treatment is performed. Quality can be stabilized.

An optical sensor 9 is located on both sides of the high-frequency heating device 1 and detects whether or not the pinion gear 7 is mounted on the first and second guide members 4 and 5. The pinion gear 7 is mounted on the optical sensor 9. If it is placed, the placement of the pinion gear 7 is confirmed by blocking the light emitted by the light sensor.
Based on this signal, the control device 11 operates to prevent the high-frequency heating device 1 from malfunctioning.
On the other hand, when the optical sensor 10 is annealed, when the operator enters the dangerous area of the high-frequency heating device 1, the control device 11 is activated based on the signal of the optical sensor 10 and the heat treatment operation is immediately stopped. Device.

FIG. 6 is a time chart showing the heat treatment procedure of the high-frequency heating device 1. After confirming that the pinion gear 7 is placed on the first and second guide members 4, 5, first, the heating coil 61 is energized. A preheating step of preheating for 15 to 20 seconds is performed.
Then, the cooling process which stops electricity supply and implements cooling for 1.5 to 3.5 second is implemented. This is because in the high frequency heating, the heating temperature rises rapidly, and only the surface becomes abnormally high, and the temperature difference from the inside is large. Therefore, the temperature difference between the surface and the intermediate layer inside by leaving the pinion gear 7 is left. This is because the conditions for annealing are adjusted by eliminating (increasing the inner temperature).
Next, an annealing heating process for 15 to 20 seconds is performed. After that, it is allowed to stand in the atmosphere and gradually cool down.
In addition, what is necessary is just to adjust suitably the time in each means with the output of the high frequency heating apparatus 1, the required specification of annealing, a material, etc. with the control apparatus 11. FIG.
The heating temperature for annealing in the present embodiment was 700 to 750 ° C.

According to the present embodiment, since the pinion gear 7 is rotated along the axis GL, no unevenness occurs in the annealing of the screw portion 73, so that the quality of the pinion gear 7 can be easily ensured.
Further, in order to rotate the pinion gear 7 along the axis GL, the driven gears 34 and 35 are fixed to the outer peripheral portions of the first and second guide members, and the drive gear 35 is used to drive the drive transmitted from the idler gear 33. Since the gear mechanism 3 is directly driven, the gear mechanism 3 becomes compact and the apparatus can be easily handled.
In addition, the structure of the gear mechanism 3 is simplified, the number of parts is reduced, and the cost of the device is reduced. Accordingly, the cost of the pinion gear 7 can be reduced.
Further, since two or more pinion gears 7 can be annealed at the same time, the annealing work can be performed efficiently and the work cost can be reduced.

  The present invention can be applied to a heat treatment apparatus that heats the outer peripheral portion of the shaft portion at high frequency.

1 High-frequency heating device 2 Base 3 Gear mechanism (drive mechanism)
4 First Guide Member 5 Second Guide Member 6 Heating Device 7 Pinion Gear 8 Rotation Sensor 9 Optical Sensor 31 Drive Motor 32 Drive Gear 33 Idler Gear 34 First Driven Gear 35 Second Driven Gear 41 Guide Sleeve 43 First Guide Part 45 Second Guide Part 61 Heating coil 62 Insulated coated electric wire 63 Gap 73 Screw part 74 Spline shaft CL Heating coil axis (second axis)
GL pinion gear axis (first axis)
RL guide member axis

Claims (5)

In a high frequency heating apparatus for a pinion gear that performs heat treatment on the shaft portion of the pinion gear having a gear portion and a shaft portion that is coaxial with and integrally formed with the axis of the gear portion,
A heating device having a high-frequency heating coil that annularly surrounds the shaft portion; a first axis of the gear portion substantially coincides with a second axis of the annular high-frequency heating coil; A cylindrical guide member that internally fits the shaft portion to support the pinion gear so as to have a uniform gap over the entire circumference between the peripheral surface and the outer peripheral surface of the shaft portion, and is coupled to the guide member. A driving mechanism for rotating the member around the second axis; a driving motor for driving the driving mechanism; and a control device for controlling driving of the driving motor and heating conditions of the heating device. A high-frequency heating device for pinion gears.   A plurality of the guide members are arranged, and among the gears constituting the drive mechanism, the driven gear connected to the guide member meshes with the driven gears to transmit the rotational driving force to the plurality of guide members. The high frequency heating apparatus for a pinion gear according to claim 1.   The high-frequency heating device for a pinion gear according to claim 1 or 2, wherein a rotation sensor for detecting the rotation of the shaft portion is disposed to face a spline shaft forming portion provided in the shaft portion.   The control device includes a preheating means for controlling preheating, and heat generated by preheating between the surface and the surface in order to perform annealing treatment of the shaft portion on which the high-frequency heating coil is disposed on the pinion gear that has been quenched. 2. The high frequency heating apparatus for a pinion gear according to claim 1, further comprising: a cooling means for controlling a standing time for reducing a temperature difference with the layer portion; and a heating means for performing main heating. In the high frequency heat processing method of a pinion gear performed using the high frequency heating apparatus of the pinion gear according to claim 1,
The pinion gear that has been subjected to the quenching process is supported on the guide member, a preheating process in which the high frequency heating coil is energized to perform preheating, a cooling process in which the cooling is performed for a certain period of time, and then the high frequency heating coil in a certain period of time. A high-frequency heat treatment method for a pinion gear, wherein the heat treatment is performed by energizing, followed by a cooling process for cooling for a certain time, and annealing is performed on a shaft portion of the pinion gear after quenching.

Images