JP4029943B2 - Jig for induction heating and hardening of gears that are easily deformed by heat - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the induction heating of a gear that heat-treats the tooth profile by induction heating, the induction heating treatment is such that the gear rib is thinly formed or a hole is provided in the rib so that the gear easily deforms by heat without induction. It relates to ingredients.
[0002]
[Prior art]
A heat treatment in which only the gear tooth profile is quenched by induction heating is widely performed . For example, a gear having a thin rib 2 as shown in FIG. 7 (a) and having a hole 2a for weight reduction, Alternatively, as shown in FIG. 7B, a gear or the like in which the ribs 2 are provided so as to be offset from the rim 3 may cause the rim 3 to wave when the tooth profile is heat-treated by induction heating, or the arrow in FIG. There is a problem in that the gear accuracy is lowered due to the inclination of the tooth streak by deforming in the direction of X so that the end diameter d of the rim 3 is reduced.
[0003]
[Problems to be solved by the invention]
In order to solve this, if the rib 2 is thickened and the strength is increased, the weight also increases. Further, it may be difficult to provide the rib 2 at the center of the rim 3 due to the configuration of the apparatus.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to provide a gear induction heating and quenching jig capable of heat-treating a gear tooth profile that is easily deformable as described above without induction deformation.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an induction heating and quenching jig for a heat-deformable gear according to the present invention has a rim having a tooth profile on the outer periphery, a boss at the center, and a rib for joining the rim and the boss. and, in the induction heating hardening jig gear the ribs to quenching by induction heating the tooth profile of the gear provided biased against one or the rib is the rim has a thin wall or vent hole, said gear rim One push plate made of a non-magnetic material provided with a contact surface that is a sloped surface that contacts one corner of the inner periphery, and a stepped portion that fits to the other corner of the inner periphery of the rim are provided. The other pressing plate made of a non-magnetic material and the both pressing plates so as to apply a force for pushing the contact surface of the one pressing plate into the inner periphery of the rim of the gear and expanding the rim of the gear in the radial direction. 1 or a plurality of tightening bolts made of a non-magnetic material for tightening It is intended.
[0006]
That is, when the pressing plates disposed on both sides of the heated gear are tightened with tightening bolts, the gradient portion of the contact portion provided on one of the pressing plates is pushed into the inner periphery of the rim of the heated gear, and this gradient portion In addition to the axial force that holds the rim of the heated gear from both sides, a radial force that increases the diameter of the end of the rim is applied. Thereby, it is possible to prevent the rim from being deformed so that the rim is waved or the diameter of the end of the rim is reduced during induction heating of the tooth profile, and a gear without deformation after heat treatment can be obtained. In addition, since the push plate and the tightening bolt are made of a non-magnetic material, they are hardly heated by induction current during induction heating, and there is no reduction in the strength of the push plate and the tightening bolt, so the effect of preventing deformation is great. .
[0007]
Further, it is desirable for the sum of the tightening forces of the one or more tightening bolts to be 8 kgf · cm or more per 1 cm of the circumferential length abutting on the inner diameter of the rim in order to suppress heating deformation. That is, as a result of the experiment, the force for pressing the gears of the two pressing plates is insufficient if the force is not more than 8 kgf · cm per 1 cm of the circumferential length of the rim inner diameter. I understood that. As a result, the number of tightening bolts is not increased unnecessarily, and the stress applied to the bolts is not excessively shortened.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described with reference to an illustrated embodiment. FIG. 1 is a sectional view of a gear induction heating jig according to an embodiment of the present invention, and FIG. 2 is a plan view thereof. FIG. 3 is a topographic view of the tooth shape before quenching in the embodiment of the present invention, and FIG. 4 is a topography of the tooth shape after quenching when induction hardening is performed without using the induction heating jig of the present invention. FIG. 5 is a topographic view of the shape of teeth after quenching when induction hardening is performed using the induction heating jig of the present invention. FIG. 6 is a plan view of a gear used in the embodiment of the present invention, and FIG. 7 is a cross-sectional view showing an example of a gear that is easily deformed by heat.
[0009]
1 and 2, the induction heating jig of the present invention includes an upper pressing plate 11, a lower pressing plate 21, and a plurality of tightening bolts 31. The upper push plate 11 and the lower push plate 21 are made of a non-magnetic material, are formed into ring-shaped discs each having a through hole 12 and 22 at the center, and are tightened at equal intervals on the circumference of the central portion of the ring width. A plurality of insertion holes 14 through which the bolts 31 are inserted are provided. And both the pushing plates 11 and 21 are arrange | positioned at the both sides | surfaces so that a to-be-heated gear may be pinched | interposed.
[0010]
The upper pressing plate 11 is provided with a gradient portion on the outer periphery of the lower surface thereof, and the gradient portion forms a contact surface 13 that contacts the inner diameter of the upper end portion of the rim 3 of the heated gear 1 in the drawing. Further, the lower pressing plate 21 is provided with a step portion on the outer periphery of the upper end surface, and the step portion is fitted to the lower inner periphery of the rim 3 of the heated gear 1 to form a fitting portion 23.
[0011]
The gradient angle α of the contact surface 13 is preferably 45 degrees to 30 degrees with respect to the axis of the gear. When the gradient angle α is 45 degrees or more, the component force for pressing the rim 3 of the heated gear in the axial direction increases, but the component force for expanding the rim 3 in the radial direction decreases, and when the gradient angle α is 30 degrees or less, the rim of the heated gear is decreased. This is because the component force that expands 3 in the radial direction increases, but the component force that presses the rim 3 in the axial direction decreases, and the effect of preventing deformation decreases.
[0012]
The plurality of tightening bolts 31 are made of, for example, a high-strength nonmagnetic stainless steel such as SUS631 defined in JIS, and the heated gear 1 is inserted into the corresponding insertion hole 14 of the upper pressing plate 11 and the insertion hole 24 of the lower pressing plate 21. And the nut 32 is screwed so that the heated gear 1 is sandwiched between the upper pressing plate 11 and the lower pressing plate 21. The screwing force is desirably 8 kgf · cm or more per 1 cm of the inner circumference of the rim 3 of the heated gear. If it is 8 kgf · cm or less, the effect of preventing deformation cannot be obtained due to insufficient heat deformation stress, but if it is 8 kgf · cm or more, it is sufficient for preventing heat deformation. The number of tightening bolts increases and it takes time for tightening, or the stress of the tightening bolt is excessive and the life is shortened.
[0013]
The operation of the gear induction heating jig configured as described above will be described below. As shown in the plan view of FIG. 6, the heated gear 1 has teeth 5 formed on the outer periphery of the rim 3, and the rim 3 and the boss 4 attached to the shaft are connected by a thin rib 2. Is provided with a hole 2a for weight reduction. Therefore, since the bending strength in the lateral direction of the rib 2 is small, the entire tooth portion is easily thermally deformed when the tooth portion is heated. As shown in FIG. 7, the end portion diameter d of the rim 3 is easily deformed to the inner diameter side when the tooth profile is heated. .
[0014]
In the induction heating jig for a gear according to the present invention, when the gear to be heated is sandwiched between the upper pressing plate 11 and the lower pressing plate 21 and tightened with the tightening bolt 31, the gradient portion of the contact surface 13 of the upper pressing plate 11 is the gear portion. It is pushed into the inner diameter of the upper end portion of the rim 3, and the force sandwiched between the upper pressing plate 11 and the lower pressing plate 21 by the component force of the gradient portion and the inner diameter of the end portion of the rim 3 are radially expanded. The power to do works. This prevents thermal deformation in which the inner diameter of the rim end portion is reduced during the tooth profile induction heating. At this time, since the upper push plate 11, the lower push plate 21 and the tightening bolt 31 are made of a non-magnetic material, they are not heated by the induced current and are not deformed due to a decrease in strength due to a temperature rise. In particular, since the temperature of the tightening bolt 31 does not increase, there is no fear that the tightening force is reduced due to heating by the induced current, and the effect of preventing thermal deformation of the gear does not decrease.
[0015]
【Example】
An embodiment in the case where the gear having the shape shown in FIG. 6 is induction heated using the induction heating jig for the gear having the above configuration will be described below. The conditions are as follows.
Gear to be heated: Pitch circle diameter: 125.0mm
Tooth width: 20mm
Module: 2.5
Rim inner diameter: 111.5mm
Induction heating jig:
Press plate: Material: JIS SUS304
Gradient of the contact portion of the upper plate: 45 degrees Tightening bolt: Material: JIS SUS631
Number: 10φ x 6
Tightening method: Tightening was performed using a torque wrench so that the force of each bolt was 50 kgf · cm.
Total tightening force: 8.57kgf · cm per rim inner circumference cm
The gear teeth were quenched by induction heating, and the inclination of the tooth trace due to deformation after quenching was measured using a topograph.
[0016]
The results of the heating experiment are shown in FIGS. 3 shows the shape of the tooth of the material gear before quenching, FIG. 4 shows the shape of the tooth when quenched without using the induction heating jig of the present invention, and FIG. 5 uses the induction heating jig of the present invention. It is the figure which each showed the shape of the tooth | gear at the time of hardening by topography.
[0017]
These figures represent the teeth indicated by (a) in each figure, with thin lines indicating calculated lines and thick lines indicating actual measurement lines. In these drawings, as can be seen from FIG. 4, when quenching is performed without using the induction heating jig of the present invention, the rim end portion is compared with the teeth of the material gear before quenching shown in FIG. Therefore, the actual tooth tip circle diameter becomes smaller, and the blade tip is displayed narrowly when viewed from the original tooth tip circle. The teeth are deformed by a maximum of 25 to 30 μm with respect to a tooth width of 20 mm. On the other hand, when the induction heating jig of the present invention shown in FIG. 5 is used for quenching, it is possible to obtain a highly accurate heat-treated gear that can prevent deformation of the ribs even after quenching and hardly change the tooth streaks before quenching. I found out that
[0018]
As described above, according to the induction heating jig for a heat-deformable gear according to the embodiment of the present invention, the gradient portions of the pressing plates disposed on both sides of the heated gear are pushed into the rim inner diameter of the heated gear. In this way, the rim of the heated gear is sandwiched with pressure by the pressing plates on both sides and induction-heated in a state where stress is applied to expand the rim in the radial direction. In this case, deformation of the rim end portion in the inner diameter direction and deformation of the rim undulation can be prevented, and heat treatment of the gear with high accuracy is possible. In addition, since the push plate and the tightening bolt are made of a non-magnetic material, it is less likely to be heated by the induction current during induction heating, and the strength of the push plate and the tightening bolt is not reduced due to a temperature rise, thereby preventing deformation. Will not drop.
[0019]
The tightening force of the plurality of tightening bolts may be 8 kgf · cm or more per circumferential length of 1 cm in contact with the inner diameter of the rim. Therefore, waste such as an increase in the number of tightening bolts can be eliminated.
[0020]
In this embodiment, a gear having six holes in the rib was used as the gear to be heated, so six tightening bolts were inserted through the holes, but if the number of tightening bolts was changed depending on the number of holes, Well, in the case of a rib without a hole, it is possible to use one thick tightening bolt inserted through the shaft hole of the boss.
[0021]
【The invention's effect】
As described above, the induction heating and quenching jig for easily deformable gears according to the present invention gives a stress that expands the inner diameter of the rim end portion, which is to be deformed to the inner diameter side by tooth profile heating, in the radial direction by the push plate. Since the heating is performed in a pressed state, even a gear that is easily deformed by heat, such as a gear having a thin rib, can be induction-heated without being deformed, and a highly accurate gear can be obtained. Further, since the push plate and the tightening bolt are formed of a non-magnetic material, they are hardly heated by the induced current, and the effect of preventing deformation is not lowered due to the strength reduction of the jig.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an induction heating jig for a gear that is easily thermally deformed according to an embodiment of the present invention.
FIG. 2 is a plan view of an induction heating jig for a gear that is easily thermally deformed according to an embodiment of the present invention.
FIG. 3 is a topographic view showing the shape of teeth before quenching according to an embodiment of the present invention.
FIG. 4 is a topographic view of the shape of teeth quenched without using the induction heating jig of the gear of the present invention.
FIG. 5 is a topographic view showing the shape of teeth quenched using the induction heating jig for gears of the present invention.
FIG. 6 is a plan view of a heated gear according to an embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a gear that easily undergoes thermal deformation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heated gear 2 Rib 2a Hole 3 Rim 4 Boss 5 Tooth 11 Upper presser plate 12 Through hole 13 Contact surface 14 Insertion hole 21 Lower presser plate 22 Through hole 23 Step part 24 Insertion hole 31 Tightening bolt 32 Nut

Claims (1)

It has a rim having a tooth shape on the outer periphery, a boss at the center, and a rib for joining the rim and the boss, and the rib is thin or has a hole, or the rib is provided to be biased with respect to the rim. in induction heating quenching jig gear quenching by induction heating the teeth of the gear, from a non-magnetic material abutting surface is a slope surface abutting on one of the corners of the peripheral rim of the gear is provided And the other pressing plate made of a non-magnetic material provided with a stepped portion fitted to the other corner of the inner periphery of the rim, and the contact surface of the one pressing plate is connected to the gear Thermal deformation characterized by comprising one or a plurality of tightening bolts made of a non-magnetic material for tightening the two pressing plates so as to apply a force for expanding the rim of the gear in the radial direction by being pushed into the inner periphery of the rim. Easy-to-use induction heating and hardening jig for gears.

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