JP3462797B2 - Method of quenching rolling members - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for quenching a rolling member, and more particularly, it is suitable for application to high frequency induction heating and quenching and cooling of the entire rolling member such as a gear. is there.

[0002]

2. Description of the Related Art Many types of parts are used as rolling members, and one example thereof is an external gear (e.g., double-row internal meshing planetary gear reducer) that is a component of an industrial speed reducer. External gear of the machine). Here, this type of external gear will be described as an example.

Conventionally, a double-row internal meshing planetary gear mechanism has been widely known. This double-row internal meshing planetary gear mechanism responds to the rotation of the first shaft and the first shaft. An eccentric body that rotates, a plurality of external gears that are attached to the eccentric body via bearings and are capable of eccentric rotation, and an internal meshing engagement with the external gears through internal teeth composed of outer pins. Internal gear and a second shaft connected to the external gear via an inner roller that extracts only the rotation component of the external gear.

6 and 7 show a more specific structure of the planetary gear mechanism described above. In the case of this structure, the first shaft serves as an input shaft and the second shaft has the same structure. Is used as an output shaft, and the internal gear is fixed, so that the structure is configured as a "speed reducer".

The structure of a conventionally used double-row internal mesh planetary gear mechanism will be briefly described with reference to FIGS. 6 and 7. First, the input axis (first axis)
The eccentric bodies 3a and 3b are fitted in 1 with a predetermined phase difference (180 ° in this example). These eccentric bodies 3
As shown in FIG. 7, a and 3b are eccentric to the input shaft 1 (center O ₁ ) by the eccentric amount e (center O ₂ ), and the eccentric bodies 3a and 3b have bearings 4a and 4b. Two external gears 5a and 5b are mounted in a double row via. These external gears 5a and 5b include
A plurality of inner roller holes 6a and 6b are provided, and the inner pin 7 and the inner roller 8 are fitted into these inner roller holes 6a and 6b, respectively. The reason why the external gears 5a and 5b are two (double row) is mainly to increase the transmission capacity, maintain the strength, and maintain the rotational balance.

External teeth 9 having a trochoidal tooth profile, an arc tooth profile or the like are provided on the outer circumferences of the external gears 5a and 5b (see FIG. 7). The external teeth 9 are internally meshed with the internal gear 10 fixed to the casing 12. Specifically, the internal teeth of the internal gear 10 have a structure in which the outer pin 11 is loosely fitted in the outer pin hole 13 and is held so as to be easily rotated. The inner pin 7 penetrating the external gears 5 a and 5 b is fixed or fitted near the output shaft 2. Thus, the eccentric bodies 3a and 3b are configured to rotate once as the input shaft 1 rotates once, and the external gears 5a and 5b are rotated by one rotation by the rotation of the eccentric bodies 3a and 3b. Although an attempt is made to oscillate around, the rotation of the internal gear 10 is restrained, so that the external gears 5a and 5b almost only oscillate while inscribed in the internal gear 10. ing.

In this case, the number of teeth of the external gears 5a and 5b is N
When the number of teeth of the internal gear 10 is N + 1, the difference in the number of teeth is 1. Therefore, the external gears 5a and 5b are displaced (rotated) by one tooth with respect to the internal gear 10 fixed to the casing 12 for each rotation of the input shaft 1. This is because one rotation of the input shaft 1 causes the external gears 5a and 5b to rotate.
It means that the rotation speed has been reduced to 1 / N of. In the rotation of the external gears 5a and 5b at this time, the swing component is absorbed by the gap between the inner roller holes 6a and 6b and the inner roller 8, and only the rotation component is transmitted via the inner pin 7 to the output shaft 2 Is transmitted to. As a result, eventually, reduction with a reduction ratio of 1 / N is achieved.

The double-row internal meshing planetary gear mechanism as described above is currently applied to various speed reducers or speed increasers. For example, in this structure, the first shaft is the input shaft 1, the second shaft is the output shaft 2, and the internal gear 10
Is fixed, but the first shaft is the input shaft 1,
It is possible to configure the speed reducer by using the internal gear 10 as the output shaft and fixing the second shaft.
Further, in these structures, the "gearbox" can be configured by reversing the input shaft and the output shaft.

By the way, as the external gear material, conventionally,
High carbon chromium bearing steel is used, and the quenching apparatus (batch furnace) 30 as shown in FIG. As shown in FIG. 9, the external gear material S (the material of the external gears 5a and 5b) that is quenched by the quenching device 30 includes a central hole 31 and a plurality of small holes at a predetermined distance from the center. 32
And a peripheral tooth 33 having a large number of teeth on the outer peripheral portion, the external gear material S is heated to a required temperature in a heating chamber 34 in which a decarburizing preventing metamorphic gas is used as an atmosphere (see FIG. In Fig. 9, P is cooled by being immersed in the oil tank 35 immediately after the temperature measurement point P at the intermediate position between the small holes 32 adjacent to each other. Then, the work (external gear material S) immersed in the oil tank 35 is cooled for a required time, then pulled up by the elevator 36, taken out of the furnace, transferred to the cleaning tank 37 and cleaned. Then, the externally toothed gear product that has been entirely quenched and washed is conveyed to the next step.

[0010]

However, in the conventional quenching method as described above, since the quenching is performed by batch processing, although the treatment amount for one time is relatively large, the quenching treatment for small-quantity multi-product production is required. Is a quenching method that is not suitable for
Also, the lead time is shortened by applying the quenching process on a series of lines (inline) (1
The reality is that it is not possible to reduce the quenching processing time per piece).

The present invention has been made in view of the above circumstances, and an object thereof is to provide a quenching method suitable for high-mix low-volume production and to shorten the lead time by in-line production. A further object of the present invention is to provide a method for quenching a rolling member such as a gear, which can quench the entire rolling member such as a gear so that there is little variation in hardness and structure.

[0012]

In order to achieve the above-mentioned object, the structure of the present invention comprises: (a) High frequency induction heating for the rolling member according to the shape and size of the rolling member made of bearing steel. And (b) rotating the rolling member about its axis under the condition that the rolling member is arranged to face the high-frequency induction heating coil, and Magnetic transformation from room temperature so that a high-frequency current is passed through the heating coil to make the temperature distribution in the inner and outer diameter direction and thickness direction of the rolling member uniform.
65 to 80 ° C / sec up to the point, and further exceeds the heating and holding temperature
Higher at required heating temperature up to 5-8 ° C / sec
After induction heating and cooling for 1 to 2 seconds, up to the heating and holding temperature
Is a heating pattern for heating at a heating rate of 1.5 to 3.5 ° C./second, and the step of uniformly high-frequency induction heating the rolling member to a required quenching temperature, (c) , The temperature distribution in the inner and outer diameter directions and the thickness direction of the rolling member heated uniformly is maintained in a uniform state, so that a good quenched structure can be obtained in the rolling member.
As described above, by sequentially performing a step of heating and holding at a constant temperature, and (d) immediately after that, a step of cooling the rolling member that has been heated and held to perform quenching treatment, the required quenching hardness is obtained. It is a method for quenching a rolling member so as to obtain a smoothness and a quenched structure. Further, in the present invention, the heating frequency of the high frequency power supply for supplying the high frequency current to the high frequency induction heating coil is set to 1 kHz to 30 kHz, and the operation of varying the power supplied to the high frequency induction heating coil intermittently or continuously is repeated. By doing so, the surface temperature and the core temperature are set to be substantially equal. Further, in the present invention, the required heating / holding temperature is controlled within a range of ± 5 ° C., and the heating / holding time is ± 3 of the required holding time.
It is controlled within the range of seconds. In the present invention, the required pressure, the required flow rate of the coolant, martensite in wells transformation start temperature 7-10 seconds to a temperature just above the M _S point is the cooling start temperature, a further martensitic transformation finish temperature M Quenching is performed by jet cooling the surface to the temperature immediately below the point _f in 15 to 25 seconds. Further, in the present invention, the rolling member made of a high carbon bearing steel material is the hardened material.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS.

In the quenching method according to the present embodiment, the entire quenching of an external gear (an external gear 5a, 5b used as a main component of a double-row internal meshing planetary gear mechanism) which is a type of rolling member is performed. This is a quenching method for quenching. That is, in the quenching method according to the present embodiment, the external gear material S (see FIG. 9) having the central hole 31, the plurality of small holes 32 at a predetermined distance from the center, and the outer peripheral teeth 33, respectively, is approximately the same. Under the condition that the half is accommodated and arranged in the high frequency induction heating coil 40 having the semi-disc box-shaped main body 40a, the external gear material S is rotated about its axis at the first position. The entire external gear material S is uniformly induction-heated to the required quenching temperature, and subsequently the entire surface layer temperature and core temperature of the external gear material S are heated to substantially equal temperatures to maintain that state. Immediately after that, the heated external gear material S is subjected to injection immersion cooling (quenching cooling) by a cooling device 41 arranged at a second position near the first position.

The quenching method will be described in more detail below. First, FIG. 1 (A), (B)
Fig. 1 shows a quenching device 20 used for quenching the external gear material S as a whole by carrying out the quenching method of the present invention. The quenching apparatus 20 includes a work holding jig 39 for holding an external gear material S to be quenched, a high frequency induction heating coil 40, and a high frequency transformer 41 for supplying a high frequency current to the high frequency induction heating coil 40. And this high frequency transformer 4
1. A transformer fine movement table 42 for adjusting the position of 1, a coil / transformer moving device 43 for moving the high frequency induction heating coil 40 and the high frequency transformer 41 together in the horizontal direction, and an external tooth gear material S vertically up and down. A work up-and-down moving device 44,
A work rotation drive device 45 that rotates the external gear material S together with the work holding jig 39, and a work transfer device 46 that horizontally transfers the external gear material S from the heating position to the cooling position.
A rail 47 on which the external gear material S is placed, a cooling device 51 including an upper cooling ring 48, a lower cooling ring 49 and a cooling ring cover 50 for quenching and cooling the external gear material S, an upper cooling ring 48 and cooling. A cooling ring vertical movement device 52 for vertically moving the ring cover 50 and a cooling oil tank 53 for storing cooling oil are provided.

The high frequency induction heating coil 40 described above is shown in FIG.
As shown in, the box is a semi-disc shape as a whole.
And a body portion 40a having a size and shape capable of accommodating and arranging approximately half of the external gear material S to be quenched, and a body portion 40a connected to the body portion 40a and facing each other with an insulator (not shown) interposed therebetween. A pair of coil lead portions 40b,
40c, each of which has a notch with a size and shape corresponding to the central hole 31 (see FIG. 9) of the external gear material S in the central portion of each of the upper surface plate 55 and the lower surface plate 56 of the main body portion 40a. 57 and 58 are provided, respectively.

The high-frequency transformer 41 described above uses the coil / transformer moving device 43 to move the high-frequency induction heating coil 40.
And the high-frequency induction heating coil 40 can reciprocate in a predetermined heating position or in a direction away from the heating position.

Next, an operation and an operation when the external gear material S is completely quenched by using the quenching device 20 having such a configuration will be described. First, the external gear material S before the quenching process is fixed by the work handling device 60 while being placed on the work holding jig 39. Next, the external tooth gear material S is moved upward together with the work holding jig 39 by the work vertical movement device 44 and installed at a height position corresponding to the main body portion 40a of the high frequency induction heating coil 40. After that, the high-frequency transformer 41 and the high-frequency induction heating coil 40 are moved in the horizontal direction by the coil / transformer moving device 43, and along with this, the external teeth are placed inside the semi-disc box-shaped main body portion 40a of the high-frequency induction heating coil 40. Almost half of the gear material S is housed and arranged with a slight gap between it and the main body 40a. At this time,
A high frequency induction heating coil 40 for the external gear material S according to the shape and dimensions of the external gear material S to be subjected to quenching treatment.
The relative position (arrangement) of the main body 40a is set.

Thereafter, as the work rotation drive motor 45a, which is the drive source of the work rotation drive device 45, is rotationally driven, the external gear material S is held by the work holding jig 39.
Along with this, the external tooth gear material S is driven to rotate about the axis thereof. At the same time, a high frequency current is supplied from a high frequency power source (not shown) to the high frequency transformer 41, and accordingly, a high frequency current is passed through the high frequency induction heating coil 40 in the direction indicated by arrow α in FIG. The heating frequency of the high-frequency power source supplied to the high-frequency induction heating coil 40 at this time is 1 to 30 k depending on the size of the external gear material S.
It is selected in the range of Hz. The high frequency induction heating of the external gear S by the high frequency induction heating coil 40 is 65 to 80 ° C./sec from room temperature to the magnetic transformation point, and 5 to 8 ° C. to the required heating temperature not exceeding the heating holding temperature described later. It is performed at a heating rate of / sec.

Further, depending on the type (shape) of the external gear material S, the high frequency transformer 41 and the high frequency induction heating coil 40
By adjusting the position of the transformer with the fine movement table 42 of the transformer, the high-frequency transformer 41 and the high-frequency induction heating coil 4 are arranged so that the heating temperature of each part of the workpiece (each part of the external gear material S) becomes uniform.
The position of 0 is adjusted. By using a ceramic holding jig 39 for the external gear material S, the external gear material S can be heated without being deprived of heat by the workpiece holding jig 39. Is desirable.

Thus, when the external tooth gear material S is heated by the high frequency induction heating action of the high frequency induction heating coil 40 and reaches a predetermined heating temperature, subsequently, the heating temperature is maintained at the heating temperature for a required time. Heating for the purpose of (maintaining) is performed. Specifically, after the external gear material S that has reached the required heating temperature is allowed to cool for 1 to 2 seconds, it is heated to the heating holding temperature at 1.5 to 3.5 ° C /
It is performed at a heating rate of 2 seconds. The temperature holding time in this case is
It is necessary to adjust according to the heating temperature, and in order to perform complete quenching (hardness and texture are good both on the surface of the external gear S and the core) with respect to the heating temperature, A temperature holding operation must be performed for at least a certain time but not more than a certain time. The amount of electric power required to maintain the temperature is determined according to the shape of the external gear material S. The heating for maintaining the temperature is controlled by changing the electric power supplied to the high frequency induction heating coil 40 intermittently or continuously so that a predetermined temperature is set as an upper limit and the temperature falls within a constant temperature maintaining range. To be done. On the other hand, the required heating and holding temperature is ± 5
The heating holding time is controlled within a range of ± 3 seconds of the required holding time while being controlled within a range of ° C.

[0022] Through such heat retaining process, when holding the temperature distribution of the external gear material (rolling members) inner and outer diameters and thickness directions of the S in the uniform state, the tissue For good quenched structure Become. Then, the heating of the external gear material S (heating by heating,
When the holding heating) is completed, the supply of the high frequency current to the high frequency induction heating coil 40 is stopped, the coil / transformer moving device 43 is activated, and the high frequency induction heating coil 40 is changed to the high frequency transformer 41. Is moved to the original position with.

Further, the rotation of the external gear material S and the work holding jig 39 is stopped in synchronization with the stop of the heating by the high frequency induction heating coil 40, and the work vertical movement device 4
It is lowered by 4 and transferred onto the rail 47. The external gear material S transferred on the rail 47 is conveyed onto the lower cooling ring 49 by the work conveying device 46, and thereafter,
The upper cooling ring 48 and the cooling ring cover 50 are moved down by the cooling ring vertical movement device 52. And the upper cooling ring 4
8 and the lower cooling ring 49 are set such that the external gear material S is sandwiched between them, and at the same time, quenching oil is supplied from the upper cooling ring 48 and the lower cooling ring 49 to the front and back surfaces of the external gear material S. The cooling ring cover 50 is filled with quenching oil (coolant). Along with this, by cooling the quenching oil at the required pressure and the required flow rate, the cooling from the cooling start temperature to the temperature just above the M _S point which is the Martensato transformation start temperature is 7 to 10.
In a second, the cooling to the temperature just below the M _f point, which is the end temperature of the martensitic transformation, is jet cooling in 15 to 25 seconds. The upper cooling ring 48 and the lower cooling ring 49 have a large number of injection holes 70, 71 as shown in FIGS.
(Hole diameter: 1.8 mm to 2.2 mm, arrangement pitch: 10
12 mm) and grooves 72 and 73 are respectively provided, and quenching oil injected from these injection holes 70 and 71 toward the external gear material S connects the grooves 72 and 73 to the external gear material S. It is discharged to the outside from both the front and back sides.

After the external gear material S is rapidly cooled to near its liquid temperature by quenching oil and quenching is completed, the upper cooling ring 48 together with the cooling ring cover 19 is moved by the cooling ring vertical moving device 52. After being moved upward, the external gear material S is transferred from the cooling position to the outside by the work transfer device 46. External gear material S that has been quenched in this way
Is cleaned by a cleaning device (not shown) to remove the attached cooling oil, and then tempered.

Next, in order to show the advantages of the external gear (rolling member) hardened by the above-mentioned hardening method, two concrete examples will be shown below.

[0026]

[Table 1]

[Table 2]

Optimum conditions for the above quenching conditions and were determined based on various heat treatment conditions and the results of quality characteristic surveys. The frequency of the high frequency power source used for the high frequency induction heating is determined to be suitable from the relationship between the plate thickness (10 mm) of the external gear material S and the penetration depth of the high frequency current,
In addition, the frequency was determined to be such that it was confirmed that there was little variation in the temperature when the temperature of the flat surface portion of the external gear material S actually increased when the external gear material S was actually heated. The heating power and temperature rise time are set to the above power and time in consideration of the quenching production cycle and the heating method that suppresses the variation in temperature when the temperature of the externally toothed gear material S rises through experiments. did.

FIG. 4 shows an implementation example of the method for heating the external gear material S according to the present invention. In this example,
In the first heating step, the external gear material S is heated to a temperature of 850 ° C. where the temperature rises most easily, and then allowed to cool to make the temperature uniform, and the high frequency power in the second heating step is set to 20 kW. By doing so, heating to the quenching temperature while keeping the temperature variation small, then,
The required heating temperature is maintained while repeating the operation of changing the electric power for heating.

Judging from the advantages of production control, it is usual to use a water-soluble coolant, but when the water-soluble coolant cools the external gear S, precipitation of an incompletely hardened structure is caused. Under the conditions (flow rate, temperature, concentration) that can prevent the occurrence of heat, it has been proved by experiments that the probability of occurrence of quench cracking is extremely high.Therefore, the use of water-soluble coolant has been postponed. It is the actual situation. Incidentally, it is easy quenching crack is generated in the case of using a water-soluble coolant, 5-8 of the cooling rate in the martensite region (M _S → M _f) is extremely fast compared to the mineral oil (mineral oil It is also supported by the temperature measurement result of double.

By setting the discharge pressure, flow rate and temperature of the coolant as described above, the temperature from the cooling start temperature to the temperature just above the M _S point (about 300 ° C. in the case of high carbon bearing steel) is 7 to 1
It is cooled for 0 seconds and further cooled to a temperature just below the M _f point (about 100 ° C in the case of high carbon bearing steel) for 15 to 25 seconds to prevent the occurrence of quench cracks and to prevent the formation of an incompletely hardened structure. It is designed to prevent precipitation. Further, the quenching oil injected from the upper cooling ring 48 and the lower cooling ring 49 cools the external gear material S, and then flows into the numerous grooves 72, 73 provided in the upper cooling ring 48 and the lower cooling ring 49. Therefore, the external gear material S is uniformly cooled as a result of being efficiently discharged.

Table 3 below shows the quality characteristics of the material that has been quenched by the above-mentioned quenching method.

[0032]

[Table 3]

As is clear from the test results shown in Table 3, decarburization is not observed despite heating in the ambient temperature atmosphere.

The material hardened under the heat treatment conditions shown in Table 2 above was tempered at 200 ° C. for 2 hours, and then finished by grinding to perform a thrust type rolling contact fatigue life test. The test conditions are as follows. Surface pressure: 540 kgf / mm ² Number of revolutions: 1800 cpm Lubricating oil: # 60 Spindle oil

As shown in FIG. 5, the test result is L for a test piece quenched by the conventional batch heat treatment method.
₁₀ life (number of repetitions until 10% of materials reach the end of life)
Showed the same durability as the conventional one. Further, the material that has been quenched under the heat treatment conditions shown in Table 2 above is tempered at 200 ° C. for 2 hours, and then finished by grinding.
The durability test was carried out by incorporating it in a speed reducer. As a result, the same life as the external gear material processed by the conventional method was exhibited, and good characteristics were obtained.

Therefore, according to the quenching method as described above, it is possible to quench the entire material corresponding to the size and shape of the external gear S, and to obtain the same quenching quality as that of the conventional quenching method. Quenching treatment. In addition, the quenching method of this example is not a batch process that is conventionally performed, but it is possible to produce a small amount of a wide variety of products depending on the shape, dimensions, mass, material, etc. of the rolling member to be quenched, It is possible to shorten the lead time by carrying out the quenching treatment by putting it on a series of lines (inline).

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment.
Various modifications and changes can be made based on the technical idea of the present invention. For example, in the above-described embodiment, the case where the external gear used in the double-row internal meshing planetary gear mechanism is entirely quenched has been described, but the quenching method of the present invention does not quench the internal gear or the like. Of course, the present invention can also be applied to quenching of various thin disk-shaped or disk-shaped rolling members different from gears and various rolling members having complicated shapes.

[0038]

As described above, according to the present invention, the arrangement of the high frequency induction heating coil for the rolling member is set according to the shape and size of the rolling member made of bearing steel, and the rolling member is subjected to high frequency induction heating. Under the condition of facing the coil, while rotating the rolling member around its axis, a temperature rising pattern that makes the temperature distribution in the inner / outer radial direction and thickness direction of the rolling member uniform, and required quenching uniformly high-frequency induction heating to a temperature, which in the temperature distribution in the uniformly heated rolling member holds uniformly constant temperature heating subsequently after the tissue for good quenched structure is heated and maintained This is a method in which the rolling members are cooled and subjected to quenching treatment to obtain the required quenching hardness and quenching structure, so the placement of the high-frequency induction heating coil on the rolling members is set appropriately. In addition to high frequency induction heating and By adjusting the degree holding method properly, the whole over uniform quenching hardness and uniform quenched structure of the rolling members (less variation quenched hardness and quenched structure)
Can be obtained.

Further, according to the present invention, the type of rolling member
By appropriately changing the layout of the high frequency induction heating coil according to (shape and size), it is possible to quench the rolling members of various sizes and shapes. It is possible to provide a highly practical quenching device for rolling members that can immediately cope with the quenching treatment of various rolling members in response to the above requirement. Moreover, since the present invention is not a method of performing quenching treatment using a batch furnace as in the prior art but a method of utilizing a high frequency induction heating coil, the quenching treatment can be performed by placing it on a series of lines (inline). It is possible to shorten the lead time.

[Brief description of drawings]

FIG. 1 schematically shows the configuration of an external gear hardening device used to carry out the hardening method of the present invention,
1 (A) is an overall configuration diagram of an external gear quenching device, FIG.
FIG. 3B is a front view of a main part showing a state where the external gear material is arranged corresponding to the high frequency induction heating coil.

FIG. 2 is a perspective view of a high-frequency induction heating coil that is a component of the external gear quenching device of FIG.

3A and 3B are views showing an injection type cooling ring for cooling a heated external gear material, wherein FIG. 3A is a plan view of an upper cooling ring and FIG. 3B is an upper cooling ring. FIG. 3 is a cross-sectional view of a lower cooling ring.

FIG. 4 is a diagram showing a heating control method for heating and holding an external gear material at a quenching temperature.

FIG. 5 is a Weibull diagram showing the results of a thrust type rolling contact fatigue life test for an external gear (rolling member) that has been induction hardened by the quenching method of the present invention.

FIG. 6 is a cross-sectional view of a double-row internal meshing planetary gear mechanism that uses an external gear that is a type of rolling member.

7 is a sectional view taken along line XX in FIG.

FIG. 8 is a schematic configuration diagram of an external gear quenching device that has been conventionally used to implement a conventional quenching method for external gear materials.

FIG. 9 is a plan view of an external gear material that is a target of quenching processing.

[Explanation of symbols]

5a, 5b External gear 20 Quenching equipment 39 Work holding jig 40 high frequency induction heating device 40a Semi-disc box-shaped main body 40b, 40c coil lead part 41 high frequency transformer 42 High Frequency Micro Motion 43 Coil / transformer moving device 44 Work vertical movement device 45 Work rotation drive 46 Work transfer device 47 rails 48 Upper cooling ring 49 Lower cooling ring 50 cooling ring cover 51 Cooling device 52 Cooling ring vertical movement device 53 Cooling oil tank 60 Work handling equipment 70,71 injection holes 72,73 groove External gear material

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsuyoshi Yamaguchi               Sumitomo, 6-1, Asahi-cho, Obu-shi, Aichi               Heavy Machinery Industry Co., Ltd. Nagoya Works (72) Inventor Tomoyuki Onuma               Sumitomo, 6-1, Asahi-cho, Obu-shi, Aichi               Heavy Machinery Industry Co., Ltd. Nagoya Works (72) Inventor Sai Kinoshita               No. 3007, Nakajima, Nakajima, Himeji City, Hyogo Prefecture               Chi Sanyo Special Steel Co., Ltd. (72) Inventor Jun Muramatsu               6102-5 Tana, Sagamihara City, Kanagawa Prefecture               Tsu 101                (56) Reference JP-A-4-331851 (JP, A)                 JP 63-28822 (JP, A)                 JP-A-50-139442 (JP, A)                 JP-A-4-318586 (JP, A)                 JP-A-3-72021 (JP, A)                 Japanese Patent Publication 4-68365 (JP, B2)                 Japanese Patent Publication Sho 48-33121 (JP, B1)

Claims (5)

(57) [Claims] 1. A step of: (a) setting an arrangement of a high-frequency induction heating coil with respect to the rolling member according to the shape and dimensions of the rolling member made of bearing steel; (b) setting the rolling member to the high-frequency wave. Under the state of being placed opposite to the induction heating coil, the rolling member is rotated around its axis, and a high frequency current is passed through the high frequency induction heating coil, so that the rolling member has inner and outer radial directions and a thickness direction. Magnetic transformation from room temperature to make the temperature distribution of
65 to 80 ° C / sec up to the point, and further exceeds the heating and holding temperature
Higher at required heating temperature up to 5-8 ° C / sec
After induction heating and cooling for 1 to 2 seconds, up to the heating and holding temperature
Is a heating pattern for heating at a heating rate of 1.5 to 3.5 ° C./second, and the step of uniformly high-frequency induction heating the rolling member to a required quenching temperature, (c) , The temperature distribution in the inner and outer diameter directions and the thickness direction of the rolling member heated uniformly is maintained in a uniform state, so that a good quenched structure can be obtained in the rolling member.
As described above, by sequentially performing a step of heating and holding at a constant temperature, and (d) immediately after that, a step of cooling the rolling member that has been heated and held to perform quenching treatment, the required quenching hardness is obtained. A method for quenching a rolling member, characterized in that a hardness and a quenching structure are obtained. 2. A heating frequency of a high frequency power source for supplying a high frequency current to the high frequency induction heating coil is set to 1 to 30 kHz, and an operation of intermittently or continuously varying the power supplied to the high frequency induction heating coil is repeated. Done,
The method for quenching a rolling member according to claim 1, wherein the surface temperature and the core temperature are set to be substantially equal to each other. 3. The required heating and holding temperature is controlled within a range of ± 5 ° C., and the heating and holding time is controlled within a range of ± 3 seconds of the required holding time. Or
The method for quenching a rolling member according to claim 2 . 4. A coolant having a required pressure and a required flow rate,
Than the cooling start temperature, which is the martensite wells transformation start temperature M
_It takes 7 to 10 seconds up to the temperature just above the _S point, and 15 to up to the temperature just below the M _f point which is the end temperature of martensitic transformation.
Any one of claims 1 to 3, characterized in that so as to quenching by injecting cooling surface in 25 seconds
Item 4. A method for quenching a rolling member according to item. Wherein said rolling member is quenched rolling member according to any one of claims 1 to 4, characterized in that a member which is constituted by bearing steel of a high carbon Method.