JPH08180966A - Heat treating method and device for thin plate annular part - Google Patents

Abstract

PURPOSE: To uniformly heat a thin plate ringlike part by induction heating, and also quench the part without distortion. CONSTITUTION: An induction heating device 2 is constituted of a carrying device 5 for a part 4 and a pair of vertical platelike induction heating coils 6 facing the carrying path of the device 3, and a cooling device 3 is constituted of a pair of vertical cooling metallic molds 23 and 24 and the drive device of the cooling device 3. In this constitution, the cooling metallic molds 23 and 24 are provided on the downstream side of the induction heating coil 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment method and a heat treatment apparatus for thin plate annular parts such as drive wheels and side plates of thrust needle roller bearings.

[0002]

2. Description of the Related Art Generally, an electric heater, a heating means by a furnace (salt bath furnace) using a gas burner as a heat source, or an induction heating means is used as a heating means required for quenching an annular thin plate part. Is used. Thin annular parts with a plate thickness of 2 mm or less (eg φ85 × φ6
As the 0 × 1 ^t ) heating means, the former heating means can obtain uniform heating, but is inefficient in terms of energy, space, efficiency and the like. The latter heating means by induction heating can apply various induction heating methods in the case of a sufficiently thick annular part, but when the plate thickness is thin, there is a problem that temperature unevenness and distortion of each part of the part are likely to occur. .

Since the conventional induction heating method is a heating method involving heat transfer in the parts, the parts other than the heating part tend to be cooled easily in the case of the parts having a thin plate thickness as described above.
It was difficult to uniformly heat the entire part in a short time of about 2 to 3 seconds.

On the other hand, in order to obtain the required hardening hardness and strain improving effect, it is necessary to avoid the temperature drop after heating in the above-mentioned thin parts and move them to the cooling step in a short time within 2 to 4 seconds. There is.

Therefore, an object of the invention according to this application is to provide a heat treatment method capable of uniformly heating an annular component having a small plate thickness in a short time to obtain a required quenching hardness and a strain improving effect.

Further, according to the invention of this application, it is possible to uniformly heat an annular part having a small plate thickness in a short time, and moreover, after heating, move to a cooling device in a short time to improve required quenching hardness and strain. It is an object of the present invention to provide a heat treatment apparatus that can obtain the effect.

[0007]

In the invention relating to the heat treatment method, a thin plate annular component is induction-heated to a predetermined temperature by a pair of upper and lower flat plate induction heating coils, and then the component is placed between cooling molds. It was designed to be pressed at.

In the invention relating to the heat treatment apparatus,
In a heat treatment apparatus for a thin plate annular component comprising an induction heating device and a cooling device, the induction heating device is constituted by a component transporting device and a pair of upper and lower flat plate induction heating coils facing the transporting path, and the cooling device is moved up and down. The cooling die is composed of a pair of cooling dies and a driving device for the cooling dies, and the cooling dies are arranged so as to be faced to a component conveying path on the downstream side of the induction heating coil.

Since the above-mentioned component faces the flat plate-shaped induction heating coil and is subjected to induction heating, the entire component is uniformly heated. The heated part is restrained and cooled by a cooling die, and quenching and distortion improvement are performed at the same time.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, an induction heating device 2 and a cooling device 3 are provided inside a casing 1 of the device.

The induction heating device 2 is composed of a conveying device 5 for the component 4 and a pair of upper and lower flat plate induction heating coils 6 (see FIG. 3).

The transfer device 5 has a guide plate 9 having a transfer passage 7 penetrating the casing 1 and a semicircular guide wall 8.
And a transport table 11 rotatably provided along the inside of the guide wall 8. The rotary shaft 12 (see FIG. 2) of the transport table 11 is supported by the casing 1.

Four recesses 13 are formed at equal intervals on the outer peripheral edge of the carrying table 11, and the parts 4 are partially received in the recesses 13.

The guide plate 9 is provided with a recess 13 located at a position facing the entrance of the transfer passage 7 and its rotation direction (see FIG. 1).
The upper and lower surfaces of another recess 13 adjacent to (see arrow a) are covered. Further, the guide wall 8 and the guide arm 14 extending toward the cooling device 3 form a semi-circular portion of the transfer passage 7, which guides the component 4.

The carrying table 11 performs an intermittent operation aligned with the cooling device 3 and the like as described later.

As shown in FIG. 1, with reference to the position of the recess 13 facing the entrance of the transport passage 7, the rotation phase of the transport table 11 in the rotation direction is the first step, the second step ... The component 4 is received in the recess 13 in the first step, induction heating is applied to it in the second step, and it is transferred to the cooling device 3 in the third step. The distortion is improved at the same time.

The induction heating coil 6 is one in which a ring is formed by one flat conductor and both ends thereof are held by the electrodes 15, and the induction heating coil 6 is provided on the upper and lower guide plates 9 at the position of the second step. It faces the upper and lower surfaces of the hole 16 (see FIG. 3).

The width of the induction heating coil 6 is as shown in FIG.
As shown in FIG. 3, it is provided so as to be wider than the width of the component 4 and to cover the width. Further, as shown in FIG. 7B, the inner diameter of the component 4 may be set to a size slightly inside the inner diameter of the coil 6.

FIGS. 7A and 7B show that when a current in the same direction is applied to each coil 6, a magnetic flux Φ is generated and an induced current in the opposite direction flows in the component 4.

In order to suppress heat generation of the coil 6,
It is desirable to attach a cooling pipe 17 to the surface opposite to the component 4 and to cool it by flowing a refrigerant through it.

Next, as shown in FIGS. 2 and 3, the cooling device 3 includes a lower mold table 19 on a rotary shaft 18 supported by the casing 1 and an upper mold with a predetermined space above it. The table 21 is attached.

On the upper surface of the lower mold table 19, there are provided recessed circular recesses 22 at equal positions along the outer peripheral surface thereof, and the lower mold 23 is housed and fixed in the recess 22. It The upper surface of the lower die table 19 and the lower die 23
The upper surface of is at the same height as the transfer passage 7 of the induction heating device 2.

Further, the recess 22 and the lower mold 23 housed inside the recess 22 are positioned so as to coincide with the component 4 at the position of the third step of the induction heating device 2 described above, and in this case also, the intermittent action is performed. Thus, with the delivery position of the above-mentioned component 4 as the first step, it is rotated in the opposite direction (see arrow b) from the first to the fourth step (symbols 1 with parentheses in FIGS. 8A and 8B). 4 represents steps 1 to 4).

As shown in FIG. 2, the upper mold table 21 is provided with an upper mold 24 at a position facing the lower mold 23. Posts 2 provided on the upper surface of each upper mold 24
Reference numeral 5 denotes a cam follower 26 which penetrates the table 21 in a vertically movable manner and has a radial support shaft at its tip.
(See FIG. 5) is attached.

A cam device 27 is provided on the ceiling surface of the casing 1.
Are provided (see FIG. 2). As shown in FIG. 5, the cam device 27 includes a large circular arc fixed cam 28 having a C-shaped planar shape, and a small circular arc fixed cam 29 facing both ends of the large circular arc fixed cam 28 at predetermined intervals.
And a pair of first and second vertical movement cams 31 and 32 which are arranged in the space. These cams 28, 29, 31, 32 are arranged annularly as a whole. The vertical movement cams 31, 32 are actuators 33 such as air cylinders mounted on the upper surface of the casing 1,
It is moved up and down by 34.

Cam grooves 35 and 36 are formed on the inner peripheral surfaces of the large arc fixed cam 28 and the small arc fixed cam 29, respectively, and the cam follower 26 is fitted therein.
The cam groove 35 of the large circular arc fixed cam 28 has a small circular arc fixed cam 29.
Is formed at a position one step lower than the cam groove 36.

Further, the cams 37 and 38 having the same radius of curvature as the centers of curvature of the cam grooves 35 and 36 are formed in the vertical movement cams 31 and 32 (see FIG. 4). By the action of the actuators 33 and 34 of
It moves up and down between the lower cam groove 35 and the upper cam groove 36.

Further, the first vertical movement cam 31 has a first
It is provided above the upper mold 24 in the step, and the second vertical movement cam 32 is provided above the upper mold 24 in the fourth step.

The lower mold 23 and the upper mold 24 are shown in FIG.
, The cooling passages 39 and 40 through which the cooling medium passes.
The cooling passage 39 of the lower die 23 communicates with the passage 42 of the rotary shaft 18 via the passage 41 of the lower die table 19. The cooling passage 40 of the upper mold 24 communicates with the passage 42 of the rotary shaft 18 through a flexible hose 43.
A coolant such as water or liquid nitrogen is supplied to the passage 42 of the rotary shaft 18 from a portion of the cap 44 at the upper end thereof.

The unloading device 45 for the component 4 after the completion of quenching is
As shown in FIG. 1, the arm 46 facing the inner periphery of the lower mold 23 of the fourth step of the cooling device 3 and the lower mold 2
3, and an actuator 48 such as an air cylinder that moves in the direction of the carry-out passage 47 along the upper surface of 3.

The cooling device 3 is driven by the driving device 49 shown in FIG. 2, and its driving force is transmitted to the induction heating device 2 through the gears 51 and 52.
Are intermittently driven by a Geneva mechanism or a roller gear index mechanism.

Energization and interruption of the induction heating coil 6, the respective operations of the actuators 33 and 34 of the vertical movement cams 31 and 32 and the actuator 48 of the carry-out device 45 are aligned so as to be synchronized with the intermittent operation of the drive device 49. It is controlled by the device 53 (see FIG. 9). The inverter 54 shown in FIG. 9 supplies an alternating current to the induction heating coil 6.

The apparatus of the embodiment is constructed as described above,
Next, the operation will be described. Thin plate ring component 4
Is continuously supplied from the transfer passage 7 shown in FIG.
Transport table 1 temporarily stopped at the step position
It is sent to the recess 13 of 1. When the transport table 11 is rotated by one step, the component 4 is moved to the position of the second step, where the induction heating coil 6 is energized. Part 4
If the size is φ85 × φ60 × 1 ^{t, the} temperature required for quenching is 840 ° C by energizing for 2-3 seconds.
Reachs 900 ° C.

After the heating is completed, the component 4 is moved onto the lower mold table 19 of the cooling device 3 and placed on the lower mold 23 in the first step of the cooling device 3 in the third step.

At this time, the first vertical movement cam 3 of the cooling device 3
Since 1 is on the upper side, the space between the lower mold 23 and the upper mold 24 is open (see FIGS. 2 and 8 (a)), and the component 4 can move onto the lower mold 23 through the gap. it can. This state is the first step of the cooling device 3.

When the cooling device 3 shifts to the second step, the first vertical movement cam 31 moves downward and the cam groove 3 thereof is moved.
8 is flush with the cam groove 35 of the large arc fixed cam 28 (see FIG. 8B), and the component 4 is pressed between the lower die 23 and the upper die 24 to start cooling. Lower mold table 19
When the upper die table 21 rotates, the cam follower 26 moves to the cam groove 35 of the large arc fixing cam 28, and the lower die 23 and the upper die 24 intermittently perform the second step while pressing the component 4. The third step is sequentially performed to reach the fourth step.

In the fourth step, the cam follower 26
Moves to the cam groove 37 of the second vertical movement cam 32, the second
Since the vertical movement cam 32 moves to the upper position, the upper mold 24 releases the component 4.

At the same time, the actuator 48 of the carry-out device 45 is actuated, and the arm 46 sends the component 4 to the carry-out passage 47.

In the above cooling device 3, the time for cooling the component 4 by pressing it between the molds 23 and 24 is 8 to 12 seconds,
The press pressure is 100 kgf, and each die 23, 2
4 is cooled below 40 ° C.

As described above, the heating time (2 to 3 seconds) by the induction heating coil 6 is shorter than the cooling time (8 to 12 seconds) by the molds 23 and 24. The number of each mold 23, 24 is selected as an integer of the quotient obtained by (cooling time) / (heating time).

Further, the transport table 11 of the induction heating device 2
Pitch diameter D ₁ of the recess 13 and each mold 2 of the cooling device 3
Relationship between the pitch diameter D ₂ of 3,24, as shown in FIG. 10, n ₁ the number of recesses 13, the number of n ₂ of each mold 23, 24
Then, D ₁ = P ₁ n ₁ / π and D ₂ = P ₂ n ₂ / π.

The pitch P _{1 of the} recesses 13 and each mold 2
Since the pitches P ₂ of 3 and 24 are the same, D ₂ = P ₁ n
It becomes ₂ / π.

The pitch diameters of the gears 51 and 52 are determined so as to correspond to the above-mentioned D ₁ and D ₂ , respectively.

In the above-mentioned heat treatment apparatus, the results of actual measurement of how the radial temperature distribution of the component 4 differs depending on the relationship between the inner and outer diameters of the component 4 and the inner and outer diameters of the heating coil 6 are shown. 11 shows.

In FIG. 11, A is B in FIG.
Is the case of the same (b). C and D are comparative examples, and FIG.
This is the case of (c) and (d). According to this result, as shown in FIG. 7A, when the inner diameter of the component 4 coincides with the inner diameter of the heating coil 6 and the inner diameters of both parts are aligned, as shown in FIG. 4 is in a positional relationship that is slightly inward, the temperature distribution is excellent in uniformity, and is too close to the outside in FIG. 7C, or too close to the inside as in FIG. 7D. It can be seen that the uniformity is poor.

Specifically, 85φ × 60φ × 1.0 (m
For the ring-shaped parts made of carburized steel in (m), induction heating was performed at 850 ° C. by energizing for 2 seconds (frequency 10 KHz), and heat treatment was performed for 2 seconds from the completion of heating to the start of restraint cooling by the cooling die. As a result of actually measuring the hardness and the warpage, the hardness is HV850-890 and the warpage is 0.02 m.
m or less (0.22 to 0.37 for conventional products
mm), and sufficient quenching and distortion improvement were achieved.

[0047]

EFFECTS OF THE INVENTION Since the invention of the heat treatment method and the heat treatment apparatus according to the present application is as described above, the thin plate ring-shaped component can be uniformly heated, and at the same time, constrained cooling is performed by the cooling die after heating. Therefore, coupled with the fact that uniform heating is possible, quenching with less distortion can be performed.

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view of an embodiment.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a partially exploded perspective view of the embodiment.

FIG. 5 is a partially transverse plan view of the same as above.

FIG. 6 is a partially transverse front view of the above.

7A to 7D are explanatory views of induction heating coils.

FIG. 8A is a development view of the operation explanation of the cam device. FIG. 8B is a development view of the operation explanation of the cam device.

FIG. 9 is a block diagram of control relationships.

FIG. 10 is an explanatory diagram of a pitch diameter

[Figure 11] Temperature distribution measurement chart

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 2 Induction heating device 3 Cooling device 4 Parts 5 Conveying device 6 Induction heating coil 7 Conveying passage 8 Guide wall 9 Guide plate 11 Conveying table 12 Rotating shaft 13 Recess 14 Guide arm 15 Electrode 16 Hole 17 Cooling pipe 18 Rotating shaft 19 Lower mold table 21 Upper mold table 22 Recess 23 Lower mold 24 Upper mold 25 Post 26 Cam follower 27 Cam device 28 Large arc fixing cam 29 Small arc fixing cam 31 1st up / down moving cam 32 2nd up / down Dynamic cam 33, 34 Actuator 35, 36, 37, 38 Cam groove 39, 40 Cooling passage 41, 42 Passage 43 Flexible hose 44 Cap 45 Discharge device 46 Arm 47 Discharge passage 48 Actuator 49 Drive device 51, 52 Gear 53 Alignment Device 54 Inverter

Claims (5)

[Claims] 1. A heat treatment method for a thin plate annular component, which comprises inductively heating a thin plate annular component to a predetermined temperature by a pair of upper and lower flat plate induction heating coils and then pressing the component between cooling dies. 2. A heat treatment device for a thin plate annular component comprising an induction heating device and a cooling device, wherein the induction heating device comprises a component transporting device and a pair of upper and lower flat plate induction heating coils facing the transporting path. A heat treatment for thin plate annular parts, characterized in that the cooling device is composed of a pair of upper and lower cooling dies and a driving device for the cooling dies, and the cooling dies are faced to a component conveying path on the downstream side of the induction heating coil. apparatus. 3. The transfer device has a parts transfer table that rotates along the inside of a transfer path, and recesses for holding parts are provided at regular intervals on the periphery of the table, and the cooling device has a lower mold and an upper part. A die transport table and an upper die up-and-down device are provided, and the component delivery table, the lower die and upper die delivery tables, and an intermittent operation alignment device for the upper die are provided. The heat treatment apparatus for a thin plate annular component according to claim 2. 4. The upper mold driving device described above, wherein the upper and lower posts are integrally provided on the upper surface of each upper mold, and the posts are vertically movably penetrated through the upper mold conveying table, and the upper end of each post is moved. When the cam follower attached to is fitted into the cam groove of the cam device, the upper cam groove and the lower cam groove are partially formed in the cam groove, and the cam follower fits into the upper cam groove. 4. The upper die is raised to receive the component, and when the cam follower fits in the lower cam groove, the component is pressed between the two dies.
The heat treatment apparatus for a ring-shaped thin plate part according to. 5. The above-mentioned cam device includes a large arc fixed cam,
It is composed of a pair of vertical moving cams arranged at both ends thereof and a small circular arc fixed cam arranged between each vertical moving cam device, and a cam groove on the inner peripheral surface of the small circular arc fixing cam on the inner peripheral surface of the large circular arc fixing cam. A lower position cam groove is formed, and the vertically moving cam device is provided so as to be vertically movable so that the cam groove selectively matches the heights of the large arc fixed cam and the small arc fixed cam. The heat treatment apparatus for a thin plate annular component according to claim 4.