JPS61235509A - Partial hardening device for annular steel parts - Google Patents

Abstract

PURPOSE:To maintain required partial hardening hardness and to provide substantial strength by partitioning the space of an annular part to an inside diameter side and outside diameter side, and providing means for injecting a cooling liquid for hardening from one of the inside diameter side and outside diameter side and injecting compressed air from the other. CONSTITUTION:The heated annular steel parts 10 is imposed on a rotary supporting base 22 and a cap member 26 is attached to the top end of a cooling water path 24. The circumferential edge 25 thereof is seated to the top end face of the part 10 by which the setting is completed. The cooling liquid is injected from ejection ports 23 of the cooling water path 24 to the inside diameter surface of the part 10 and the top and bottom end faces on the inside diameter side partitioned of the partition member consisting of the base 22 and the member 26 by which the part is quickly cooled. The compressed air ejection pipe 28 toward the outside diameter surface of the part 10. The inside diameter side of the annular steel parts 10 is thereby hardened to the required adequate hardness and the outside diameter side thereof is maintained at the hardness approximately equal to the tempered hardness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a partial hardening device for mm-shaped annular parts, and more specifically, the outer peripheral surface of a forklift mast roller bearing, which is in rolling contact with a mast rail, has a hardening hardness of approximately HB30. A steel annular part that is kept at the same hardness and the inner peripheral surface on which the rolling elements roll is hardened to an appropriate hardness of, for example, H, 60, or an outer ring of a roller bearing used in a conveyance device, etc. This invention relates to a method for quenching steel annular parts that require different hardness on inner and outer diameter surfaces.

For example, in a forklift mast roller bearing, the mast rail on which the outer ring rolls is made of general mechanical structural steel such as 545C. If the rail surface is hardened to about 460, the rail surface will be extremely worn, resulting in a significant decrease in durability, and the abrasion powder will scatter, significantly deteriorating the working environment. In addition, since such an outer ring has high hardness as a whole, it is easy to break when an impact load or large load is applied, and since the material is not resilient, the outer ring breaks into many pieces and scatters, causing injury to workers. Accidents that cause harm have occurred.

In order to prevent such risk of wear and damage, as shown in Figure 1, a carburized material is used for the outer ring 1, and after flameproofing is applied to the outer circumferential surface, the inner circumferential surface and both end surfaces are treated with flameproofing. The hardened layer 2 is formed by carburizing and quenching, but this is difficult because the flameproofing treatment is extremely troublesome and requires a lot of work time and a lot of energy, and the material is expensive. It has the disadvantage of significantly increasing costs. In addition, in order to provide the strength of the outer ring of the bearing, it is necessary to carburize it to a sufficiently deep depth, but this requires a significant amount of time and energy, and even then it is difficult to obtain a sufficient carburizing depth. However, it has the disadvantage that it tends to cause problems such as not being able to obtain sufficient strength.

This invention has different hardness on the inner and outer circumferential surfaces, and is capable of handling large loads.
When hardening steel annular parts, such as the outer ring of a mast roller bearing, which has sufficient strength to withstand high impact forces, an inexpensive material such as 355C is used to maintain the required partial hardness. The purpose of this invention is to exhibit sufficient strength and to greatly facilitate the quenching process, thereby significantly reducing the cost.

To explain an embodiment, a steel annular part 1 heated to a predetermined quenching temperature is placed in a quenching apparatus 20 as shown in FIG.
0 cents. The steel annular part IO is, for example, 355C.
After forming an inexpensive hardenable general structural steel material such as the following into a desired shape (the outer ring of a mast roller bearing shown in the figure) by turning or the like, it is heated to a predetermined hardening temperature using an electric furnace or the like.

On the other hand, the quenching device 20 includes a rotary support 22 having a stepped portion 21 on which the steel annular component 10 is placed and supported by an outer diameter guide, and a rotary support 22 that penetrates through the center of the rotation support 22 and supports the steel annular component 10 on the support 22. A cooling water channel 24 equipped with a large number of coolant jet holes 23 facing the inner diameter surface of the annular component 10, and a steel pipe removably attached to the upper end of the cooling water channel 24 and having a peripheral edge 25 on a rotating support 22. An annular structure comprising a lid member 26 that concentrically contacts the upper end surface of the annular component 10 and a large number of compressed air jet holes 27 that concentrically face the outer peripheral surface of the steel annular component 10 at regular intervals. The inner diameter edge 29 of the stepped portion 21 of the rotary support 22 is in close contact with the lower end surface of the steel annular component IO placed thereon, and the edge 29 and the lid member 26 are Peripheral part 25
As a result, the space on the inner and outer peripheries of the steel annular component lOO is partitioned into an inner diameter space 30 and an outer diameter space 40. That is, the rotating support 22 and the lid member 26 are partition members for partitioning the space.

Then, the steel annular component 10 heated to a predetermined temperature is placed on the rotating support 22, and the lid member 26 is attached to the upper end of the cooling water channel 24, so that the peripheral edge 25 is placed on the upper end surface of the component 10. Complete the set by seating it. (The rotation abutment may be rotated after the setting is completed.) Once the setting is completed, from the jet hole 23 of the cooling water channel 24 to the inner diameter surface of the steel annular component 10 and both upper and lower end surfaces of the inner diameter side partitioned by the partition member. On the other hand, a cooling liquid is injected to rapidly cool the steel annular part 10, and at the same time, compressed air is injected from the jet hole 27 of the compressed air jet pipe 28 to the outer diameter surface of the steel annular part 10, so that the inner diameter side of the steel annular part is cooled as required. In addition to being quenched to the appropriate hardness,
The outer diameter side is kept at almost the same hardness as the refining hardness.

In addition, the hardened part dimension t1. with respect to the thickness T at both ends.
t2 is a rotating support 2 which is a partition member as shown in FIG.
The diameter Di of the inner peripheral edge 29 of the step portion 21 of No. 2 and the lid member 2
The inner diameter D2 of the peripheral edge portion 25 of No. 6 can be arbitrarily determined by appropriately adjusting the inner diameter D2.

In the above example, the hardness distribution in the center section along the ■-■ line is Ht up to a depth of about 3 days on the track side, as shown in
c It has a hardness of 60 or more, and the hardness decreases as it reaches the outer diameter, and the refraction point is at the 7th fin position, and from there the outer peripheral surface (in this case, the ring body thickness is 1 lin) Until H30.

Note that the steel annular part is not limited to the shape shown in Figure 3, but can also have the shape shown in Figure 4 or other shapes.
It is also possible to harden the outer diameter side and maintain the hardness of the inner diameter side to be approximately the same as the tempered hardness, or to arbitrarily set the dimensions of the hardened portion relative to the thickness of both end surfaces. Further, as the material used, general structural carbon steel within the range of about 540C-360C, such as 555C and 545C, can be used.

Further, the hardening device 20 according to the present invention is not limited to the one illustrated in FIG. 2, and the design can be changed to another structure having the same function. For example, cooling liquids include water, oil,
Any other cooling liquid may be appropriately selected depending on the material used, the intended hardness, the quenching depth, etc., and the cooling rate may be similarly adjusted as appropriate.

According to the quenching apparatus of the present invention, as described above, the space on the inner and outer periphery of a steel annular part made of a general structural steel material that can be quenched and heated to a predetermined quenching temperature is divided by partition members that are in contact with both end surfaces of the part. The cooling liquid is divided into an inner diameter side and an outer diameter side, and the cooling liquid for quenching is injected toward the steel annular part from either the inner diameter side or the outer diameter side, and at the same time compressed air is injected from the other side. At the same time as the injected side is quenched, the other peripheral surface can be made to have almost the same hardness as the refining hardness, so that the quench hardened part is hardened at both ends as shown with dark hatching in Figure 3. deep, central (III-III
A steel annular part having a shallow concave hardened layer with a radius of curvature R was obtained.

Although the steel annular parts are made of general structural steel materials such as 355C, which are inexpensive due to the formation of the hardened layer in the above-mentioned state, they are not made by conventional carburizing and quenching, or by induction hardening. The quenching depth was sufficiently deep compared to those subjected to surface hardening treatment by, for example, the strength required for the outer ring of a bearing that also serves as a mast roller.

In particular, the quenched layer has a concave cross-sectional shape with a radius of curvature of approximately R as shown in Figure 3, and this quenched layer is continuous from the inner diameter side toward both end faces and is formed into a homogeneous hardened layer. The dimensions of the hardened portion of the surface portion are increased appropriately from the center portion relative to the thickness of the annular component, and for example, the effect of reinforcing the raceway surface of the outer ring of a bearing is significantly increased, increasing its rigidity and strength. In addition, the hardness of the outer diameter portion, which is almost equivalent to the tempered hardness, improves toughness and greatly improves resistance to large loads and high impact forces, and is highly effective in preventing wear of mating parts, such as mast rollers. Met.

Furthermore, according to the quenching apparatus of the present invention, the quenching coolant is injected toward the steel annular component from either the inner diameter side or the outer diameter side, and at the same time, compressed air is injected from the other side to inject the coolant. Since the injected side is hardened and at the same time the other peripheral surface is hardened to approximately the same hardness as the refining hardness, the hardening process only needs to be done once, making process control easy and allowing continuous production of homogeneous products. It has become easier.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional steel annular part, Fig. 2 is a diagram showing an example of the quenching device according to the present invention, and Fig. 3, 5, and 4 are examples of a steel annular part quenched by the same device. FIG. 5 is a cross-sectional view showing the hardness distribution of the same part. lO... Steel annular part, 20... Quenching device, 22
...Rotating support (partition member), 24...Cooling water channel (
cooling liquid injection means), 26...lid member (partition member),
28... Compressed air jet pipe, 30... Inner diameter side space, 4
0... Outer diameter side space Applicant: Osaka Bearing Manufacturing Co., Ltd. 118i'- Procedural amendment filed in 1985 Patent Application No. 198191 2, Title of invention 11 Partial quenching device for annular parts 3, ? Relationship with the 1i corrective case Patent applicant name Name Osaka Bearing Manufacturing Co., Ltd. Name Koyo Netsujiri Co., Ltd.

Claims (3)

[Claims] (1) A partition member that partitions the space between the inner and outer peripheries of the steel annular component into an inner diameter side and an outer diameter side in contact with both end surfaces of the component, and a steel annular component that is connected to either the inner diameter side or the outer diameter side. and a compressed air injection means that injects compressed air toward the steel annular part from the remaining inner diameter side and outer diameter side. Partial hardening equipment for steel annular parts. (2) Partial hardening of the steel annular part according to claim (1), wherein the diameter of the partition member is adjusted so that the hardening range of both end faces of the steel hardened part can be adjusted. Device. (3) Claim (1) or (2) characterized in that the cooling liquid is injected from the inner diameter side of the steel annular component and the compressed air is simultaneously injected onto the outer peripheral surface. Partial hardening equipment for steel annular parts.