Conical carburizing steel bearing outer ring quenching die and quenching process thereof

Abstract

The invention belongs to the technical field of bearing heat treatment, and relates to a conical carburizing steel bearing outer ring quenching mold and a quenching process thereof.The mold comprises a cone frustum body used for supporting the inner surface of a bearing outer ring, and a cylindrical frustum body integrated with the cone frustum body is arranged at the bottom of the cone frustum body; the cone frustum body comprises a straight platform part and a frustum part, the straight platform part is of a cylindrical structure, the straight platform part is connected with the small-diameter end of the frustum part, the outer diameter of the straight platform part is the same as that of the small-diameter end of the frustum part, the outer diameter of the frustum part is gradually increased from top to bottom, and the large-diameter end of the frustum part is connected with the cylindrical platform body; the outer diameter of the cylindrical table body is greater than that of the large-diameter end of the frustum part; a plurality of upper oil flowing grooves are formed in the outer ring surface of the cone frustum body, a plurality of lower oil flowing grooves are formed in the upper surface of the cylindrical frustum body, the upper oil flowing grooves and the lower oil flowing grooves are in one-to-one correspondence, and each group of corresponding upper oil flowing grooves and lower oil flowing grooves are communicated with each other. According to the quenching die, the straight table part is adopted for supporting the ferrule, and shrinkage and expansion deformation of the ferrule is strictly controlled.

Description

Technical Field

[0001] The invention belongs to the technical field of bearing heat treatment, and in particular relates to a quenching die for an outer ring of a conical carburized steel bearing and a quenching process thereof. Background Art

[0002] In recent years, with the development of my country's manufacturing industry, the shape of bearings has become more and more complex, the size has become larger and larger, the effective wall thickness has become thicker and thicker, and the angle design of steel cold-rolled tapered rings has become larger and larger. If the previous quenching die design method is used, it can no longer meet the requirements of heat treatment of carburized steel bearing rings and cannot guarantee the service life of steel cold-rolled tapered bearings. Therefore, it is necessary to design the quenching die for tapered carburized steel bearings during the heat treatment quenching process. Summary of the invention

[0003] In view of the defects of the above-mentioned prior art, the purpose of the present invention is to provide a quenching die for the outer ring of a conical carburizing steel bearing and a quenching process thereof, so as to overcome the problem of large-angle quenching taper of steel-type cold-rolled conical carburizing steel bearings.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present invention is as follows: a quenching die for the outer ring of a conical carburizing steel bearing comprises a truncated cone body for supporting the inner surface of the outer ring of the bearing, a cylindrical cone body integrated with the truncated cone body is arranged at the bottom of the truncated cone body; the truncated cone body comprises a straight cone part and a frustum part, the straight cone part is a cylindrical structure, the straight cone part is connected with the small diameter end of the frustum part, the outer diameter of the straight cone part is the same as the outer diameter of the small diameter end of the frustum part, the outer diameter of the frustum part gradually increases from top to bottom, the large diameter end of the frustum part is connected with the cylindrical cone body, and the outer diameter of the cylindrical cone body is greater than the outer diameter of the large diameter end of the frustum part; a plurality of upstream oil grooves are arranged on the outer annular surface of the truncated cone body, and a plurality of downstream oil grooves are arranged on the upper surface of the cylindrical cone body, the plurality of upstream oil grooves and the plurality of downstream oil grooves correspond to each other, and each group of corresponding upstream oil grooves and downstream oil grooves are interconnected.

[0005] Furthermore, the bottom of each group of corresponding upstream oil grooves and the bottom of the downstream oil grooves are perpendicular to each other.

[0006] Furthermore, a circle of oil flow annular grooves is arranged at the connection between the frustum body and the cylindrical body, and the oil flow annular grooves are connected to all the upstream oil grooves and downstream oil grooves.

[0007] Furthermore, the plurality of upstream oil grooves on the outer annular surface of the truncated cone are distributed along the generatrix direction, and the plurality of downstream oil grooves on the upper surface of the cylindrical cone are distributed radially, and the groove widths of the upstream oil grooves and the downstream oil grooves are consistent.

[0008] Furthermore, some of the upstream oil grooves are vertically grooved from top to bottom, and the bottoms of some of the upstream oil grooves are parallel to the axis of the frustum; some of the downstream oil grooves are horizontally grooved, and the bottoms of some of the downstream oil grooves are perpendicular to the axis of the cylindrical body.

[0009] Furthermore, the frustum body and the cylindrical body are coaxially arranged, and the frustum body and the cylindrical body are provided with interconnected hollow cavities.

[0010] Furthermore, a plurality of bosses are evenly distributed on the outer cylindrical surface of the cylindrical body, and the upper surfaces of the plurality of bosses are continued with the downstream oil groove.

[0011] Furthermore, the outer diameter of the straight table portion of the truncated cone is 0.5-1 mm larger than the inner diameter of the wide end surface of the bearing outer ring.

[0012] Furthermore, the outer diameter of the large diameter end of the frustum portion of the frustum body is 1-4 mm smaller than the inner diameter of the narrow end face of the bearing outer ring.

[0013] The quenching process of the above-mentioned conical carburizing steel bearing outer ring quenching mold is adopted. The outer ring of the bearing is heated to 815°C in a box furnace for austenitization and kept warm for 100 minutes. After being taken out of the furnace, the outer ring is clamped on the quenching mold and placed in quenching oil at 40-50°C for quenching, and then tempered at a tempering temperature of 155°C for 12 hours.

[0014] Furthermore, each furnace in the box-type furnace has a loading capacity of two pieces, and the large end faces of the two bearing outer rings are stacked.

[0015] The beneficial effects of the present invention are as follows: the quenching die of the present invention adopts a straight table portion to support the ferrule, and the shrinkage and expansion deformation of the ferrule is strictly controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional view of the quenching die of the present invention; Figure 2 A top view of the quenching die of the present invention; Figure 3 This is the product picture of the tapered outer ring; In the figure: 1, frustum body, 1.1 straight table part, 1.2 frustum part, 2, cylindrical table body, 3, upstream oil groove, 4, downstream oil groove, 5, oil flow ring groove, 6, hollow cavity, 7, wide end face of cone outer ring, 8, narrow end face of cone outer ring, 9, inner diameter chamfer of wide end face of cone outer ring. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0018] The original steel tapered carburized steel bearing (ring outer diameter size is consistent, inner diameter is tapered, the thickest part of the ring is 58mm, and the thinnest part is 25mm) has a small oil flow port in the quenching die design. At the same time, the oil flow port design is designed according to the outer raceway angle of the outer ring. The actual oil groove of the die is particularly narrow, and the oil flow is small, which cannot guarantee the quenching cooling capacity, resulting in a great difference in cooling at the thickest and thinnest parts of the tapered carburized steel bearing. At the same time, the die angle design is consistent with the ring angle combined with cooling, which makes it impossible to ensure the consistency of the outer diameter taper on both sides of the ring, and the hardness and hardened layer depth cannot be guaranteed, resulting in the heat treatment quality and service life of the steel cold-rolled tapered bearing cannot be guaranteed. For this reason, this patent optimizes the design of the original die.

[0019] See attached Figure 1-3 , a quenching die for the outer ring of a conical carburizing steel bearing comprises a truncated cone body 1 for supporting the inner surface of the outer ring of the bearing, the bottom of the truncated cone body 1 has a cylindrical cone body 2 which is integrated with the truncated cone body, the truncated cone body 1 and the cylindrical cone body 2 are coaxially arranged, the outer diameter of the truncated cone body 1 gradually increases from top to bottom, the large diameter end of the truncated cone body 1 is connected with the cylindrical cone body 2, and the outer diameter of the cylindrical cone body 2 is larger than the outer diameter of the large diameter end of the truncated cone body 1; the truncated cone body comprises a straight cone part 1.1 and a frustum part 1.2, the straight cone part 1.1 is a cylindrical structure, the straight cone part 1.1 is connected with the small diameter end of the frustum part 1.2, and the outer diameter of the straight cone part 1.1 is the same as the outer diameter of the small diameter end of the frustum part 1.2 The outer diameter of the frustum part 1.2 gradually increases from top to bottom, and the large diameter end of the frustum part 1.2 is connected with the cylindrical body 2, and the outer diameter of the cylindrical body 2 is larger than the outer diameter of the large diameter end of the frustum part 1.2; a plurality of upstream oil grooves 3 are arranged on the outer ring surface of the frustum body 1, and a plurality of downstream oil grooves 4 are arranged on the upper surface of the cylindrical body, and the plurality of upstream oil grooves 3 and the plurality of downstream oil grooves 4 correspond to each other, and each group of corresponding upstream oil grooves 3 and downstream oil grooves 4 are interconnected, and the bottom of each group of corresponding upstream oil grooves 3 and the bottom of downstream oil grooves 4 are perpendicular to each other, and a circle of oil flow annular grooves 5 are arranged at the connection between the frustum body 1 and the cylindrical body 2, and the oil flow annular grooves 5 connect all the upstream oil grooves 3 and the downstream oil grooves 4.

[0020] Based on the above technical solution, the optimized steel-type conical carburized steel bearing quenching die increases the oil groove depth and cancels the angle design, so that the quenching oil circulation of the quenching die is increased and the quenching cooling capacity is improved; the groove width of the upstream oil groove and the downstream oil groove through which the oil passes is increased to 45mm, and the oil flow is large, which further improves the quenching cooling capacity of the die and improves the cooling uniformity of the surface and core of the cold-rolled conical carburized steel bearing of the steel type. The axial width of the straight table portion 1.1 matches the axial width of the inner diameter chamfer of the wide end face of the conical outer ring. Before the heat treatment of the conical outer ring, the inner diameter chamfer of the wide end face is first processed into a cylindrical straight table surface. After the heat treatment, the cylindrical straight table surface is processed to form an arc chamfer.

[0021] Furthermore, the plurality of upstream oil grooves 3 on the outer annular surface of the frustum body 1 are distributed along the generatrix direction, and the plurality of downstream oil grooves 4 on the upper surface of the cylindrical body 2 are distributed radially, and the groove widths of the upstream oil grooves 3 and the downstream oil grooves 4 are consistent, both being 45 mm.

[0022] Furthermore, some of the upstream oil grooves 3 are vertically grooved from top to bottom, and the groove depths of some of the upstream oil grooves 3 located in the frustum part 1.2 gradually increase from top to bottom, and the groove bottoms of some of the upstream oil grooves 3 are parallel to the axis of the frustum body 1; some of the downstream oil grooves 4 are horizontally grooved, and the groove bottoms of some of the downstream oil grooves 4 are perpendicular to the axis of the cylindrical body 2.

[0023] Furthermore, the frustum body 1 and the cylindrical body 2 are provided with interconnected hollow cavities 6 .

[0024] Furthermore, four bosses 7 are evenly distributed on the outer cylindrical surface of the cylindrical body 2 , and the upper surface of the bosses 7 continues with the downstream oil groove 4 .

[0025] Furthermore, the outer diameter of the straight cone portion 1.1 of the truncated cone is 0.5-1 mm larger than the inner diameter of the wide end face of the bearing outer ring. The outer diameter of the large diameter end of the truncated cone portion 1.2 of the truncated cone is 1-4 mm smaller than the inner diameter of the narrow end face of the bearing outer ring.

[0026] Based on the above technical solution, by optimizing the die angle, the die diameter size at the thinnest part of the cone is smaller than the corresponding ring diameter size, and the die diameter size at the thickest part of the cone is larger than the corresponding ring diameter size. The outer diameter of the ring is made less than 0.5mm, thereby ensuring the uniformity of the carburized layer of the cold-rolled tapered bearing of steel and improving the heat treatment quality and service life. After the quenching of the outer ring, the allowance is removed by machining. The different diameter sizes of the wide end face and the narrow end face of the outer diameter of the ring lead to the taper of the outer diameter and the raceway. The removal amount is different during machining, and the depth of the carburized layer is uneven. When designing the mold, the size of the mold is based on the turning size of the outer ring. Therefore, the size of the cone die is smaller than the turning ring diameter size, and the thickest point is larger than the turning outer ring diameter size. Among them, the taper less than 0.5mm is the product requirement of the tapered outer ring. The larger the taper, the greater the impact on the outer diameter of the ring and the depth of the carburized layer of the outer raceway after machining. The outer diameter of the straight portion 1.1 is 0.5-1mm larger than the inner diameter of the wide end face of the bearing outer ring, which can not only support the outer ring and limit its shrinkage, but also prevent the outer diameter of the straight portion 1.1 from being too large and locking with the outer ring during heat treatment.

[0027] The secondary quenching process of the outer ring is as follows: the outer ring of the bearing is turned with a processing allowance. After turning, the outer ring is heated to 815°C in a box furnace for austenitization. The holding time is 100 minutes. Each furnace is loaded with 2 pieces (the large end faces are stacked on each other). After taking out of the furnace, the two outer rings are placed on the above-mentioned mold using a fixture, followed by quenching in 40-50°C rapid quenching oil. The tempering temperature is: 155°C, and the time is 12 hours.

[0028] After several years of production practice, the optimized steel tapered carburized steel bearing quenching die has completely solved the problems of large-angle outer ring taper and the problem of the hardened layer being unable to meet the uniformity after machining. See Table 1 and Table 2.

[0029] Table 1. Dimensional changes of the outer ring after secondary quenching using the original quenching die Outer ring number The distance between the outer diameter of the wide end face after quenching and the finished product size / mm The distance between the outer diameter of the narrow end face after quenching and the finished product size / mm The allowance between the outer diameter of the lathe before quenching and the finished product size / mm 1# 2.0-2.4 3.0-3.6 2.2 2# 2.25-2.5 2.9-3.45 2.2 3# 2.1-2.2 3.0-3.4 2.2 4# 1.9-2.3 3.2-3.7 2.2 5# 2.12-2.45 3.24-3.80 2.2 6# 2.01-2.20 2.95-3.40 2.2 7# 2.0-2.10 2.8-3.30 2.2 8# 2.05-2.32 2.96-3.60 2.2 9# 1.96-2.10 3.0-3.65 2.2 10# 2.2-2.3 3.4-3.95 2.2 Table 2. Dimensional changes of the outer ring after secondary quenching using the quenching die of the present invention Outer ring number The distance between the outer diameter of the wide end face after quenching and the finished product size / mm The distance between the outer diameter of the narrow end face after quenching and the finished product size / mm The allowance between the outer diameter of the lathe before quenching and the finished product size / mm 1# 2.04-2.20 2.10-2.21 2.2 2# 2.10-2.20 2.2 -2.34 2.2 3# 2.07-2.13 2.06-2.13 2.2 4# 2.34-2.46 2.40-2.50 2.2 5# 2.12-2.21 2.0-2.10 2.2 6# 2.10-2.24 2.05-2.12 2.2 7# 2.0-2.16 2.05-2.12 2.2 8# 2.02-2.20 2.10-2.21 2.2 9# 1.96-2.02 2.14-2.23 2.2 10# 2.16-2.32 2.12-2.23 2.2 By using two kinds of dies, 10 outer rings with an outer diameter of 820 mm were subjected to secondary quenching and tempering size verification. Taking piece No. 1 of each test group as an example, the ring was quenched using the original die. The outer diameter allowance of the ring before quenching was 2.2 mm, and the outer diameter allowance of the wide end face of piece No. 1 after quenching was 2.0-2.4 mm, that is, the size was reduced by -0.2~0.2 mm (-0.2 means the size was reduced by 0.2 mm, 0.2 means the size was expanded by 0.2 mm, and the end points of the range value are the size changes at different circumferential positions. The outer diameter allowance of the narrow end face of part No. 1 after quenching is 3.0-3.6mm, that is, it shrinks by 0.8~1.4mm; the improved mold after the present application is used to quench the ring, and the turning outer diameter allowance of the ring before quenching is 2.2mm, and the outer diameter allowance of the wide end face of part No. 1 after quenching is 2.04-2.20mm, that is, it shrinks by -1.6~0mm, and the outer diameter allowance of the narrow end face of part No. 1 after quenching is 2.10-2.21mm, that is, it shrinks by -0.1~0.01mm.

[0030] It is concluded that by changing the root size (C size) of the large diameter end of the mold cone part, the outer ring is heated to austenitization and then cooled. Since the root size (C size) is 2.36mm smaller than the narrow end size of the outer ring, the outer ring is in a free quenching state when cooling without the constraint of the mold surface. Then, the wide end face of the outer ring is shaped during the quenching process through the straight table support (D) of the mold, thereby ensuring the consistency of the shrinkage and expansion of the outer diameter of the wide end face and the narrow end face. When the optimized mold quenches the ferrule, the shrinkage and expansion of the outer diameter of the wide end face and the narrow end face becomes smaller, which is more beneficial to the depth of the carburized layer and more uniform.

[0031] Use the straight table support (D) to prevent the outer ring from bursting upward when the mold is under pressure, which makes it impossible to control the product size. At the same time, shrink the mold base size (C size) by 1-4mm to shrink the outer diameter of the narrow end face. Avoid the problem of different expansion and contraction caused by the angle problem of the ring during carburizing caused by the conventional design of the original mold, which causes the outer diameter of the narrow end face to penetrate, and the outer diameter of the wide end face cannot penetrate due to the width problem.

[0032] It should be noted that the parts not described in detail in the present invention are prior art.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0035] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0037] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0038] The above examples are only the best embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or associated with the contents disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. Quenching die for outer ring of conical carburized steel bearing, characterized by: It comprises a frustum body for supporting the inner surface of the outer ring of the bearing, wherein a cylindrical body integrated with the frustum body is arranged at the bottom of the frustum body; the frustum body comprises a straight table portion and a frustum portion, wherein the straight table portion is a cylindrical structure, the straight table portion is connected with the small diameter end of the frustum portion, the outer diameter of the straight table portion is the same as the outer diameter of the small diameter end of the frustum portion, the outer diameter of the frustum portion gradually increases from top to bottom, the large diameter end of the frustum portion is connected with the cylindrical body, and the outer diameter of the cylindrical body is greater than the outer diameter of the large diameter end of the frustum portion; a plurality of upstream oil grooves are arranged on the outer annular surface of the frustum body, and a plurality of downstream oil grooves are arranged on the upper surface of the cylindrical body, the plurality of upstream oil grooves and the plurality of downstream oil grooves correspond to each other, and each group of corresponding upstream oil grooves and downstream oil grooves are interconnected.

2. The cone-type carburized steel bearing outer ring quenching die according to claim 1, characterized in that: The bottom of each group of corresponding upstream oil grooves and the bottom of the downstream oil grooves are perpendicular to each other; a circle of oil flow annular grooves is arranged at the joint of the frustum body and the cylindrical body, and the oil flow annular grooves connect all the upstream oil grooves and the downstream oil grooves.

3. The conical carburizing steel bearing outer ring quenching die according to claim 1, characterized in that: The plurality of upstream oil grooves on the outer ring surface of the truncated cone are distributed along the generatrix direction, and the plurality of downstream oil grooves on the upper surface of the cylindrical cone are distributed radially, and the widths of the upstream oil grooves and the downstream oil grooves are consistent.

4. The quenching die for the outer ring of a conical carburizing steel bearing according to any one of claims 1 to 3, characterized in that: Some of the upstream oil grooves are vertically grooved from top to bottom, and the groove bottoms of some of the upstream oil grooves are parallel to the axis of the frustum; some of the downstream oil grooves are horizontally grooved, and the groove bottoms of some of the downstream oil grooves are perpendicular to the axis of the cylindrical body.

5. The conical carburizing steel bearing outer ring quenching die according to claim 1, characterized in that: The frustum body and the cylindrical body are coaxially arranged, and the frustum body and the cylindrical body are provided with interconnected hollow cavities.

6. The conical carburizing steel bearing outer ring quenching die according to claim 1, characterized in that: A plurality of bosses are evenly distributed on the outer cylindrical surface of the cylindrical body, and the upper surfaces of the plurality of bosses are continued with the downstream oil groove.

7. The cone-type carburized steel bearing outer ring quenching die according to claim 1, characterized in that: The outer diameter of the straight table portion of the truncated cone is 0.5-1 mm larger than the inner diameter of the wide end surface of the bearing outer ring.

8. The cone-type carburized steel bearing outer ring quenching die according to claim 1, characterized in that: The outer diameter of the large diameter end of the frustum part of the frustum body is 1-4 mm smaller than the inner diameter of the narrow end face of the bearing outer ring.

9. A quenching process using a quenching die for a conical carburizing steel bearing outer ring as claimed in any one of claims 1 to 8, characterized in that: The outer ring of the bearing is heated to 815°C in a box furnace for austenitization, and the holding time is 100 minutes. After being taken out of the furnace, the outer ring is clamped on the quenching mold, put into the quenching oil at 40-50°C for quenching, and then tempered at a tempering temperature of 155°C for 12 hours.

10. The quenching process according to claim 9, characterized in that: Each furnace in the box-type furnace is loaded with two pieces, and the large end faces of the two bearing outer rings are stacked on top of each other.

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