JPS6050112A - Method for induction hardening member - Google Patents

Abstract

PURPOSE:To reduce the production of a hardening strain in a member, to improve the dimensional accuracy after hardening, and to make the surface hardening uniform by supplying electric current to a high frequency heating means in a cooling liq. to heat the member having a suitable thickness. CONSTITUTION:A high frequency heating means 17 is placed along a surface of a member 11 to be hardened. The member 11 has a suitable thickness. A cooling liq. is fed to the surface of the member 11 to be hardened and the opposite surface from cooling liq. feeding pipes 15, 24. While supplying electric current to the means 17 in the cooling liq., the member 11 is moved properly and relatively to carry out induction hardening. By this method the production of a hardening strain is reduced, the dimensional accuracy after the hardening is improved, and the surface hardening is made uniform.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a method for induction hardening of members, for example, for applying surface hardening treatment to the heavily loaded surface portions of tri-board type universal joints and Barfield type universal joints. This invention relates to a suitable induction hardening method for one member.

(Prior Art) FIGS. 1 and 2 are a longitudinal sectional view and an explanatory view of the outer ring of a tri-board type joint showing the state of joint connection, respectively, in which the joint pin 3 of the shaft 2 is located inside the outer ring 1. The joint is connected and disconnected by going in and out. That is, the outer ring 1 has a total of three receiving parts 4 for receiving the joint pins 3 of the shaft 2, and by fitting the joint pins 3 into the receiving parts 4, the connection between the support 2 and the outer ring 1 is Rotation transmission is performed at

In this case, each inner surface 4a, 4b of the receiving part 4 provided on the outer ring 1
Since a strong load is applied between the joint pin 3 and the joint pin 3, it is necessary to perform surface hardening treatment.

Conventionally, when performing a surface hardening treatment, that is, a quenching treatment, on the inner surface 4a and the dowel of such a cup-shaped outer ring 1, it is preferable to perform induction hardening, and in particular, it is preferable to use a displacement hardening method. This transfer quenching method is described in the "New Edition Steel Handbook" (
As described in Maruzen Co., Ltd., 4th edition, p. 1246), it is ``a device in which heating and cooling are sequentially performed from one end at a constant speed by a feeding device, and then the heating and cooling are carried out to the other end.'' Specifically, for example, after placing the outer ring 1 with its opening f'' side facing downward and inserting the high frequency heating coil from the lower part of the opening,
There is a moving quenching method in which the high-frequency heating coil is moved upwards or the outer ring is moved downwards to heat it sequentially, and then cooling water is jetted to the heated area to cool it sequentially. A one-shot quenching method, in which a high-frequency heating coil is placed inside the outer ring 1 with the outer ring 1 facing upward or downward, and then electricity is applied to heat the entire inner surface of the outer ring 1 at once, and then cooling water is jetted out for quenching. was there.

However, in the conventional hardening methods shown in (1) and (2) above, the parts are heated with high frequency and then cooled water is jetted out to rapidly cool them, resulting in large quenching distortion and the size of the parts after induction hardening. There were problems such as low accuracy and the need to perform finishing work for corrections in some cases.

(Objective of the Invention) The present invention was made by focusing on the conventional problems as described above, and it is possible to achieve extremely low quenching distortion during induction hardening, and high dimensional accuracy of the member after induction hardening. The object of the present invention is to provide a method for induction hardening a member, which can uniformly perform surface hardening treatment.

(Structure of the Invention) When induction hardening a member having an appropriate wall thickness, the present invention provides a method for arranging a high frequency heating means on the quenched surface side of the member, and arranging a high frequency heating means on the quenched surface side of the member and on the opposite side thereof. It is characterized in that an appropriate amount, for example, the minimum necessary amount of cooling liquid is supplied to each surface side, and induction hardening is performed by energizing the high-frequency heating means in the cooling liquid and moving the high-frequency heating means relative to each other as appropriate.

The parts to which this invention is applied include a wide range of parts and materials, such as automobile parts and materials, machine tool parts and materials, construction machinery parts and materials, agricultural machinery parts and materials, etc. Examples include bearings and joints.

Further, induction hardening is performed by using an induction hardening device equipped with an oscillation device for induction hardening having an appropriate frequency and high-frequency heating means such as a high-frequency heating coil.
In the present invention, it is possible to use a conventionally known induction hardening apparatus, but it is also desirable to use one whose specifications are appropriately changed depending on the member to which it is applied.

Furthermore, the cooling liquid has an appropriate cooling ability to ensure sufficient hardening without causing cracks in the member during quenching, and is odorless during the quenching process.

It is desirable to have characteristics such as smokeless, non-toxic, easy to obtain, low cost, easy to manage, and long life.
In addition to water, any suitable special coolant can be used.

Then, an appropriate amount, for example, the minimum necessary amount of cooling liquid is supplied to the quenching surface side and the opposite side of the member, and the high-frequency heating means is heated in the cooling liquid to a predetermined quenching temperature, After heating to the above-mentioned quenching temperature while appropriately moving relative to each other, induction quenching is performed by rapidly cooling at the same time.

(Embodiment) Fig. 3 is a diagram showing an embodiment of the present invention, and in this embodiment, the case where the outer ring of a tri-board type universal joint is induction hardened is taken as an example. This outer ring 11 is an outer ring of a type joint, and is placed on a support stand 12 with its shaft portion facing downward. This outer ring 1
A high-frequency heating coil 13 and a heating coil holding member 14 constituting high-frequency heating means are arranged above 1.
A cooling liquid supply pipe 15 is located approximately in the center of the high frequency heating coil 13.
There are only a few words left hanging. At the bottom of this coolant supply t'r'f15, there are several high-frequency heating coil cores 17 which together with the high-frequency heating coil 13' constitute a high-frequency heating means. This high-frequency heating coil core 17 is provided with a cooling liquid distribution pipe 18 therein, and an inner circumferential cooling liquid jacket 1 having a nozzle 19a at its lower part.
It has 2.

On the other hand, a coolant jacket member 22 is fixed to the heating coil holding member 14 via a connecting member 21,
This coolant jacket mounting member 22 has a large number of nozzles 2.
There are several cooling liquid jackets 23 for the outer periphery having a diameter of 3a, and this cooling liquid jacket 23 for the outer periphery has a
is connected. At this time, the outer cooling liquid jacket 2
3 and a high-frequency heating coil core 17 which is a high-frequency heating means are arranged at approximately the same height and can move up and down integrally. The inner circumferential side can be heated and cooled simultaneously with the heating and cooling of the inner peripheral side.

Next, the procedure for induction hardening the outer ring 11 will be explained with reference to FIGS. 3 and 4.

First, the outer ring 11 to be induction hardened is placed on the support stand 12, and then the high frequency heating coil 13, the coolant feed pipe 15. High frequency heating coil core 17, inner circumferential cooling liquid jacket 12. The outer circumferential coolant jacket 23 and the like are lowered together, or the support stand 12 is raised together with the outer ring 11, and the high-frequency heating coil core 17 is moved from the point C shown in FIG. It is relatively moved to the position of point A shown in FIG. 4, which is the lower end position.

Next, as shown in FIG. 4, for example, cooling water is supplied from the cooling fluid supply/ri'15, and the cooling water from the cooling fluid supply pipe 15 is supplied to the outer ring 11 as shown by the dashed line in FIG. It passes between the inner periphery and the high-frequency heating coil core 17 from the bottom surface of the outer ring 11 and is ejected upward, so that the inner periphery of the outer ring 11 can be cooled during this time. At the same time, cooling water is jetted out from the nozzle 23a of the outer circumferential cooling liquid jacket 23 to cool the outer circumferential side of the outer ring 11.

Next, after a time t1 shown in FIG. 4 has elapsed, the high-frequency heating coil 13 is energized, and the lower end of the inner peripheral surface of the outer ring 11 is heated by the high-frequency heating coil core 17. After heating is stopped for a time t2 shown in FIG. 4, the high-frequency heating coil 13
．． Coolant supply pipe 15, high frequency heating coil core 17. The outer circumferential coolant jacket 23 and the like are slowly moved upward together (or the support base 12 is moved downward together with the outer ring 11) to the position of point B shown in FIG. During this time,
The inner circumferential surface of the outer ring 11 is heated to a predetermined hardening temperature by high-frequency heating and then immediately cooled to undergo high-frequency hardening.

When the position of point B is reached, the power supply to the high-frequency heating coil 13 is stopped, and while the high-frequency heating coil 13 etc. are being pulled up, the supply of cooling water to the inner and outer circumferential surfaces of the outer ring 11 is terminated after time t3 has elapsed, and the high-frequency heating coil 13 is stopped. heating coil 13
When the outer ring 11 reaches a point C' which is the upper end position of the outer ring 11, the outer ring 11 whose inner peripheral surface has been completely hardened is taken out.

In this way, the inner circumferential surface of the outer ring 11 is heated and hardened at the same time, and according to an example of implementation, in induction hardening of the outer ring 11 with an inner diameter of 33.34 mm, in the conventional case, the inner diameter after quenching is In contrast, in the case of the present invention, the inner diameter after quenching was about 33.25 to 33.30 mm, which was about 0.04 to 33.30 mm.
Only a very small quenching strain of 0.09 mm occurred.

In addition, in the case of underwater quenching, the cooling water stagnates, steam formation occurs, resulting in uneven quenching, and a considerable amount of electrical input is required. In the quenching method, a minimum amount of coolant is flowed to create a thin layer of water between the high-frequency heating means and the inner surface of the outer ring 11.
During the heating of the outer ring 11, this water film is continuously formed by a new coolant flow whose water temperature is controlled, so there is no uneven heating, and the water film is formed sequentially after the conventional heating. It has the advantage that it can be heated with approximately the same electric capacity as the electric capacity used during cooling moving quenching, and it can also save energy.

In the case of the embodiment shown in the figure, since the outer ring 11 is installed with its opening facing upward, the quenching range can be reduced to the bottom in 1 minute, and therefore the bottom can be quenched more easily than in the conventional case. Since the heat treatment effect is large, there is no need to increase the thickness of the bottom part, which has the advantage that the weight and amount of materials used can be reduced.

(Effects of the Invention) As described above, according to the present invention, when induction hardening a member having an appropriate wall thickness, the high frequency heating means is disposed on the hardened surface side of the member, and the Induction hardening is performed by supplying an appropriate amount of cooling liquid, for example, the minimum necessary amount, to the hardened surface side of the member and the opposite side thereof, and moving the high-frequency heating means appropriately while energizing the cooling liquid in the cooling liquid. Because of this, it is possible to significantly reduce the occurrence of quenching distortion during induction hardening of a member with an appropriate wall thickness, and it is possible to significantly improve the dimensional accuracy of the member after induction hardening. It is possible to uniformly harden the surface of the component without causing uneven heating.
In addition, since the high-frequency heating means is heated by electricity in the coolant, the high-frequency heating means is less deformed and has a longer life.Compared to the conventional transfer hardening method, the simultaneous hardening method of the present invention reduces the amount of heat in the coolant. It has very good effects such as easy management.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view showing an example of a joint connection state of a tri-board type joint, Fig. 2 (a) and (b) are longitudinal cross-sectional views and side views of the outer ring constituting the joint in Fig. 1, and Fig. 3 FIG. 4 is a longitudinal cross-sectional explanatory view of an induction hardening procedure showing an embodiment of the present invention, and FIG. 4 is a time course explanatory diagram showing the same induction hardening procedure. 11... Outer ring (member), 13... High frequency heating coil (high frequency heating means), 15... Cooling liquid feed pipe, 17... High frequency heating coil core (high frequency heating means), 18... Cooling Ministry of Liquid Distribution, 12... Cooling liquid jacket for inner circumference, 23... Cooling liquid jacket for outer circumference. Patent applicant: Nissan Motor Co., Ltd. Representative Patent Attorney Foshio Oshio Figure 2 (8) Figure 3 15 Figure 4

Claims (1)

[Claims] (1) When induction hardening a member having an appropriate wall thickness, a high frequency heating means is provided on the hardened surface side of the member, and a cooling liquid is installed on the hardened surface side and the opposite side of the member. A method for induction hardening of a member, characterized in that the induction hardening is performed by supplying the cooling liquid and energizing the high frequency heating means in the cooling liquid while appropriately moving the high frequency heating means relative to each other.