JP4551060B2 - Induction hardening method for rod-shaped members - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is generally a rod-shaped member having a solid shaft portion at both ends and a hollow pipe portion between the solid shaft portions at both ends, for example, a CVJ (constant velocity joint) part of an automobile. The present invention relates to an induction hardening method for a rod-shaped member for continuously induction-hardening an outer peripheral surface of a rod-shaped member made of a metal material such as a drive shaft.
[0002]
[Prior art]
Conventionally, shown is the CVJ components of this type of motor vehicle, the front view of a general drive shaft (made of solid portion only (solid shaft portion medium) no hollow pipe portion therein) 20 in FIG. The function of the drive shaft 20 is to transmit torque from the inboard joint to the outboard joint, for example, to transmit the power of the engine of the automobile to the wheels.
[0003]
In the case of an FF (front engine front drive) vehicle, a resonance phenomenon caused by bending vibration occurs at a constant rotational speed on the long side of the drive shaft 20, and the running feeling of the vehicle is significantly impaired. As a method for avoiding such a resonance phenomenon, a rubber damper has been conventionally attached to the drive shaft 20 to reduce the resonance phenomenon. However, in recent years, a hollow drive shaft having a large bending rigidity and a sectional view thereof as shown in FIG. 21 came to be used.
In general, the hollow drive shaft 21 is manufactured by joining the solid shaft portions 21a, 21a and the hollow pipe portion 21b at both ends by friction welding at the friction welding portions 21c, 21c, and thereafter The outer peripheral surface is quenched by high frequency induction heating.
[0004]
[Problems to be solved by the invention]
However, in the induction hardening of the outer peripheral surface of the long hollow drive shaft 21, when the hardened layer depth is 5 mm, the hollow drive shaft 21 is moved in the length direction using a high frequency of 10 kHz or less. Quenching is performed.
As shown in the sectional view of FIG. 6, the hollow drive shaft 21 of the elongated, solid in both ends (that the entire interior is an entity) shaft portion 21a, and 21a, and the hollow pipe portion 21b between these two ends There, it said solid shaft portion 21a, if the hardened layer depth of 21a in 5 mm, the the thickness of the hollow pipe portion 21b is 5 mm, all hollow pipe portion 21b is dip quenching (thick hardenability Quenching).
[0005]
In induction hardening, since the boundary of the hardened layer depth hits the changing point of compressive stress and tensile stress, when the changing point of stress occurs at the boundary between the solid shaft parts 21a, 21a and the hollow pipe part 21b having different shapes, As shown in FIG. 7, the fire cracks 22 are likely to occur. While the hollow cracks 22 in the hollow drive shaft (hardened member) 21 remain in a non-destructive state, the cracks 22 cannot be inspected by magnetic flaw detection and color check. There was a problem.
[0006]
The present invention has been made in view of such points, and the object thereof is to solve the above-mentioned problems, and as a member to be hardened, there are solid shaft portions at both ends and a hollow pipe between the solid shaft portions at both ends. Induction hardening of a rod-shaped member having a portion, the hollow pipe portion is not submerged, and no induction cracking occurs at the boundary between the solid shaft portion and the hollow pipe portion. Is to propose.
[0007]
[Means for Solving the Problems]
The configuration of the present invention for achieving the above object is for induction-hardening the outer peripheral surface of a rod-shaped member having a solid shaft portion at both ends and having a hollow pipe portion between the solid shaft portions at both ends. In the induction hardening method for the rod-shaped member, the rod-shaped member is moved in the length direction through a region surrounded by one high-frequency heating coil, and the outer circumferential surface of the rod-shaped member is induction-induced by the high-frequency heating coil. When the outer peripheral surface is quenched and quenched after heating, high frequency heating power of a plurality of frequencies from a low frequency to a high frequency is simultaneously supplied to the high frequency heating coil, and the outer peripheral surface of the member to be quenched the high-frequency induction heating, wherein the plurality of frequencies, two different in frequency, and a frequency of from 1 kHz 400kHz, first, lower frequency and a first high frequency relative to said solid shaft portion When supplying heating power, the first low frequency heating power is greater than the first high frequency heating power, and a second low frequency and a second high for the hollow pipe portion. When supplying the heating power of the frequency, the second low frequency heating power is smaller than the second high frequency heating power, and the second low frequency and the second high frequency Is less than the first low frequency heating power.
[0008]
This is a method for induction hardening of a rod-shaped member in which the heating time by the high-frequency heating power of the plurality of frequencies can be arbitrarily changed independently.
[0009]
This is an induction hardening method for a rod-shaped member in which a part (center portion) of the rod-shaped member to be quenched is hollow.
[0010]
In the method of induction hardening of a rod-shaped member, the plurality of frequencies are two different frequencies and a frequency of 1 kHz to 400 kHz.
[0011]
The present invention, induction hardening Irigata method of the rod-like member, which is configured as described above, as an object to be the hardened material, the rod member having a hollow pipe portion Upon for induction hardening, in the outer real axis portion A high-frequency heating coil is disposed on the outer peripheral surface side of the rod-shaped component having a diameter and a thickness different from that of the hollow pipe portion , and one or both of the high-frequency heating coil and the rod-shaped member are moved (in both cases, Oite to how to induction hardening while moving) is allowed in the opposite direction, at the same time it supplies the high-frequency heating power of the high frequency heating coil to one or more frequencies (a frequency of from 1 kHz 400kHz), the ratio of the heating power (or distribution ) Is changed, the quench hardening depth from the outer peripheral surface of the rod-shaped member is changed. In particular, the hardening depth is set along the thickness of the outer peripheral surface of the hollow pipe portion .
[0012]
According to the present invention, when induction-hardening a rod-shaped member having a hollow pipe portion , the hollow pipe portion is not submerged, thereby causing a crack at the boundary between the solid shaft portion and the hollow pipe portion. Will not occur.
[0013]
The present invention is a technique related to the “heating depth adjustment method in high-frequency induction heating” (proposed in Japanese Patent Application No. 2002-154974) previously proposed by the present applicant, and is an improved technique thereof.
[0014]
The technique of the “heating depth adjustment method in high-frequency induction heating” is a technique in which two high-frequency heating powers of a low frequency and a high frequency are simultaneously supplied to one high-frequency heating coil, so that the heating depth from the surface of the object to be heated is increased. The solution (method) is a method of adjusting the heating depth from the surface of the heated body when the heated body is subjected to high frequency induction heating.
That is, two high frequency heating powers of a low frequency and a high frequency are simultaneously supplied to one high frequency heating coil used for the heated body to heat the heated body by high frequency induction, and one frequency The distribution of the high-frequency power of the second frequency and the high-frequency power of the other frequency is changed to an arbitrary distribution ratio or distribution ratio, or the heating time by each of the two high-frequency powers is arbitrarily and independently changed, so In this method, the heating depth from the surface of the heating body is arbitrarily or continuously adjusted.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an embodiment of a method for induction hardening of a rod-shaped member and an induction hardening apparatus according to the present invention, in which a drive shaft having a hollow pipe part is passed through a high-frequency heating coil. However, FIG. 2 is an explanatory block diagram of the induction hardening apparatus for induction hardening, and FIG. 2 shows a high frequency applied to the induction heating coil in each part of the drive shaft in the longitudinal direction when the drive shaft is moved and quenched according to FIG. FIG. 3 is a diagram showing a heating power supply or a heating cycle, and FIG. 3 is a sectional view of the drive shaft showing a pattern in which a hardened hardened layer is formed on the outer peripheral surface of the drive shaft when induction hardening is performed according to FIG. is there.
[0016]
In FIG. 1, an induction hardening apparatus 1 is a general CVJ (constant velocity joint) part of an automobile, which is a cylindrical member made of a metal material, for example, a steel material, as a rod-like material to be hardened. With the drive shaft, the outer peripheral surface 2a of the drive shaft 2 is induction-hardened by high frequency movement while the drive shaft 2 having a hollow pipe portion in part is moved in the direction of the arrow.
The drive shaft 2 is structurally equivalent to the drive shaft 21 shown in FIG. 5, and a solid shaft portion at both ends and a hollow pipe portion at the center are joined and formed by friction welding at a friction welding portion. It consists of
[0017]
The induction hardening apparatus 1 controls (on and off) a high frequency heating coil 3 that penetrates and moves the drive shaft 2 from a dual frequency oscillator 4 as a dual frequency high frequency power supply by a control device 5. The high frequency heating power of two frequencies of the low frequency f1 and the high frequency f2 is simultaneously supplied. And immediately after heating the heating portion 2b of the outer peripheral portion 2a of the drive shaft 2 to a predetermined quenching temperature, from the coolant injection ring 6a via the coolant supply device 6 under the control of the control device 5, Cooling liquid, for example, cooling water, is jetted toward the heated outer peripheral surface 2a to quench it, and induction hardening is performed on the outer peripheral surface 2a to form a hardened and hardened layer 2c. During the induction hardening, the drive shaft 2 is moved in the direction of the arrow in the length direction by the transfer device 7.
In addition to the dual frequency oscillator 4 and the coolant supply device 6, the control device 5 also controls the transport device 7 that moves the drive shaft 2 at an arbitrary constant speed in its length direction.
[0018]
The two-frequency oscillator 4 includes a first high-frequency oscillator 4a that outputs a high-frequency heating power of the low frequency f1, for example, 3 kHz, and a second high-frequency oscillation that outputs the high-frequency heating power of the high frequency f2, for example, 200 kHz. The control device 5 adjusts the output of the high-frequency heating power from the first high-frequency power supply unit 4a, and arbitrarily controls (turns on and off) the heating time for outputting the high-frequency heating power. Further, the second high frequency oscillator 4b adjusts the output of the high frequency heating power, and arbitrarily controls (turns on and off) the heating time for outputting the high frequency heating power, and further, the first high frequency oscillation It is also possible to alternately output the machine 4a and the second high-frequency oscillator 4b.
[0019]
Further, the control device 5 connects a monitoring coil 8 wound independently together with the high-frequency heating coil 3 to the high-frequency heating coil 3 from the first and second high-frequency oscillators 4a and 4b. The first and second high-frequency oscillators 4a and 4b are controlled while monitoring the output state of each high-frequency heating power.
[0020]
At the same time, the control device 5, with respect to the high frequency heating coil 3 to heat the drive shaft 2, the low have frequency output from the first high-frequency oscillator 4a of the 2-frequency oscillator 4 a high frequency power of f1, the second distribution ratio of the high frequency electric power of the high frequency oscillator 4b the high has frequency f2 output from the entire high-frequency power respectively required for any distribution ratio or the distribution ratio (heating, For example, the quenching depth from the outer peripheral surface 2a of the drive shaft 2 can be changed by changing the heating time by the high frequency heating power of each of the two frequencies independently and arbitrarily. It can be adjusted arbitrarily or continuously.
[0021]
The control device 5, the relative high-frequency heating coil 3, a high-frequency heating power of the low have frequencies f1 output from the dual-frequency oscillator 4, the high frequency power of the not high frequency f2 By changing the distribution ratio to an arbitrary distribution ratio or distribution ratio, and at the same time, independently changing the heating time by the high-frequency heating power of each of the two frequencies from the outer peripheral surface 2a of the drive shaft 2 The quenching depth can be adjusted arbitrarily or continuously.
[0022]
Next, as shown in FIG. 2, in each part of the solid shaft portion and the hollow pipe portion of the drive shaft 2, the frequencies f1 and f2 for heating the outer peripheral surface 2a with high frequency and the ratio of the high frequency power (distribution ratio or The distribution ratio was changed and supplied to the high-frequency heating coil 3 (specific examples are described later). That is, the solid shaft portion supplies a large amount of power at a low frequency f1, and the hollow pipe portion simultaneously supplies a small amount of power compared to the large power at the solid shaft portion by a high frequency f2 and a low frequency f1. did. In particular, the heating power of the hollow pipe portion, was less than the heating power of the higher frequency f2 of the heating power of the low frequency f1. Wherein the use frequency f2 higher in the hollow pipe portion, it is possible to shallow penetration depth by high frequency induction heating, it was possible to avoid the complete quenching of the hollow pipe section.
[0023]
According to the present embodiment, the hardened and hardened layer 3c pattern obtained on the outer peripheral surface 2a of the drive shaft 2 is a hardened and hardened layer of about 5 mm at the solid shaft portion as shown in FIG. In the hollow pipe portion , a hardened and hardened layer having a thickness of about 3 mm was obtained. In the hollow pipe portion , it is possible to achieve a further quench hardening depth by distributing the heating power output of the high frequency f2 and the low frequency f1.
According to the present embodiment, as shown in FIG. 3, the hardened hardened layer 2c pattern along the outer peripheral surface 2a in the length direction of the drive shaft 2 is formed, so that the internal crack of the drive shaft 2 is prevented. Could be prevented.
[0024]
[Example]
Specific examples according to the present embodiment are shown below.
(1) Hardened member: Drive shaft (a) Material: S40BCM
(B) Dimensions: solid shaft outer diameter 30 mm, the hollow pipe portion outer diameter 40 mm (wall thickness = 5 mm), length 500mm
(2) High frequency induction heating conditions 1) Solid shaft part (a) Low frequency f1 = 3 kHz, heating power output = 120 kW (distribution ratio = 100%),
Movement speed (feed speed) = 30mm / sec
(B) High frequency f2 = 200 kHz, heating power output = 0 kW (distribution ratio = 0%),
2) Hollow pipe part (a) Low frequency f1 = 3 kHz, heating power output = 40 kW (distribution ratio = 36%),
Movement speed (feed speed) = 30mm / sec
(B) High frequency f2 = 200 kHz, heating power output = 70 kW (distribution ratio = 64%),
Movement speed (feed speed) = 30mm / sec
[0025]
The surface hardness of the solid shaft spline valley when the drive shaft 2 is quenched according to the processing conditions is Hv 700 to 720, and the hardened layer depth is 5.0 to 5.5 mm. is there. The surface hardness of the hollow pipe portion having a thickness of 5 mm is Hv 700 to 720, and the depth of the hardened layer is 3.0 to 3.3 mm.
[0026]
In the conventional induction hardening method, the surface hardness of the hollow pipe portion is Hv 700 to 720, and the hardened layer depth is 5 mm, which has been quenched to all thicknesses, but according to the present embodiment, The hollow pipe portion has a predetermined surface hardness of Hv 700 to 720 and a hardened layer depth narrower than the wall thickness (that is, the hollow pipe portion does not become hardened) . Burning cracks could be prevented.
[0027]
As described above, one embodiment of the present invention has been described. However, the present invention is not limited to this embodiment, and various modifications and changes can be made based on the technical idea of the present invention. . For example, although the number of oscillators is two, it is not limited to two and may be increased as necessary. In heating the hollow pipe portion , the high-frequency heating power of the high frequency f2 and the low frequency f1 is simultaneously supplied to the high-frequency heating coil 3, but it is also possible to supply only the high frequency f2. Further, in the high-frequency heating of the solid shaft portion, only the low frequency f1 is supplied, but it is also possible to supply high-frequency heating power simultaneously with the high frequency f2 and the low frequency f1.
[0028]
The high-frequency heating power of the low frequency f1 and the high frequency f2 is set to a constant value during heating, but the power value is stepless depending on the quench hardened layer depth required for the member to be hardened. It can be changed. The solid shaft portion and the hollow pipe portion are continuously moved and quenched in the length direction, but partial quenching in which only a necessary portion is quenched is also possible.
[0029]
【The invention's effect】
As is apparent from the above description, according to the induction hardening method and apparatus for a rod-shaped member to be heated according to the present invention, the high-frequency heating coil that penetrates and moves the member to be hardened has a low frequency to a high frequency. supplying a plurality of high-frequency heating power of frequencies simultaneously, the addition to the high frequency induction heating of the outer circumferential surface of the the hardened material, the proportion of high-frequency power of each frequency, so arbitrarily changed include zero, hollow part When induction-quenching the outer peripheral surface of a rod-shaped member to be heated having a pipe part , or in an induction hardening apparatus, the hollow pipe part is not submerged, and the solid shaft part and the hollow pipe part There is an excellent effect that no burning crack occurs at the border of the film.
[0030]
Further, according to the present invention, each of the outer peripheral surface of the rod-shaped member to be heated made of the said in thickness and the actual shaft portion having an outer diameter different different hollow pipe section upon to induction hardening, single number or a plurality of The rod-shaped member to be heated is supplied by simultaneously supplying high-frequency heating power of a frequency, induction-heating the outer peripheral surface of the member to be quenched, and arbitrarily changing the ratio of the high-frequency power of each frequency including zero It becomes possible to make it an arbitrary quenching hardening depth along the outer peripheral surface, and it is possible to prevent quench cracks inside the hollow pipe portion .
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of an induction hardening method for a rod-like member and an induction hardening apparatus according to the present invention, wherein a drive shaft having a hollow pipe part in part is passed through and moved through a high-frequency heating coil. However, it is an explanatory block diagram of the induction hardening apparatus for induction hardening.
FIG. 2 is a diagram showing the supply or heating cycle of high-frequency heating power to a high-frequency heating coil at each position in the longitudinal direction of the drive shaft at the time of moving quenching of the drive shaft according to FIG. 3 shows each part in the length direction of the drive shaft, and the vertical axis shows the high-frequency heating power supplied to the high-frequency heating coil in each part in the length direction of the drive shaft moving at a constant speed.
[Figure 3] 1227168345156_1
FIG. 3 is a cross-sectional view of the drive shaft showing a pattern in which a hardened hardened layer is formed on the outer peripheral surface of the drive shaft when induction hardened according to FIG. 2.
[4] In CVJ automotive parts that are conventionally used, is a front view showing a general drive shaft (consisting of only the real axis portion medium).
FIG. 5 is a cross-sectional view of a hollow drive shaft having a hollow pipe portion in a conventional CVJ part of an automobile.
FIG. 6 is a cross-sectional view showing a hardened hardening layer pattern formed on a hollow drive shaft having a hollow pipe portion by a conventional induction hardening method.
FIG. 7 is a cross-sectional view showing quench cracks generated in a hollow drive shaft having a hollow pipe portion by a conventional induction hardening method.
[Explanation of symbols]
1 Induction hardening device 2,21 Drive shaft (hardened member)
2a Outer peripheral surface 2b Heated portion 2c Hardened and hardened layer 3 High frequency heating coil 4 Two frequency oscillator 4a First high frequency oscillator (outputs low frequency f1)
4b Second high-frequency oscillator (outputs high frequency f2)
5 Control Device 6 Coolant Supply Device 6a Coolant Injection Ring 7 Conveyance Device

Claims (2)

In the induction hardening method of the rod-shaped member for induction-hardening the outer peripheral surface of the rod-shaped member having a solid shaft portion at both ends and having a hollow pipe portion between the solid shaft portions at both ends,
While the rod-shaped member is moved in the length direction through a region surrounded by one high-frequency heating coil, the outer circumferential surface of the rod-shaped member is heated by high-frequency induction by the high-frequency heating coil, and then the outer circumferential surface is rapidly cooled. And when quenching,
To the high-frequency heating coil, simultaneously supplying high-frequency heating power of a plurality of frequencies from a low frequency to a high frequency, high-frequency induction heating the outer peripheral surface of the member to be hardened ,
The plurality of frequencies are two different frequencies and a frequency of 1 kHz to 400 kHz;
When supplying the first low frequency heating power and the first high frequency heating power to the solid shaft portion, the first low frequency heating power is larger than the first high frequency heating power. And
When supplying the second low frequency heating power and the second high frequency heating power to the hollow pipe portion, the second low frequency heating power is smaller than the second high frequency heating power. And the second low frequency and second high frequency heating powers are smaller than the first low frequency heating powers . 2. The induction hardening method for a rod-shaped member according to claim 1, wherein the second low frequency heating power and the second high frequency heating power are larger than the first high frequency heating power. .

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