A hard metal assembly pinch roll

Abstract

The utility model relates to a kind of hard alloy assembly pinch roll, belong to steel rolling equipment technical field.The pinch roll includes roll ring, base and cover plate;The base and cover plate are all ladder shaft structure, and are divided into thick section and thin section;The base is coaxially arranged with cover plate and thin section is opposite, is fixedly connected by fastener, and two thin sections butt joint form the roll ring installation groove extending in circumference;The base and cover plate central through hole are equipped with inner hole;The roll ring is set in base and cover plate outer, and the inner hole of roll ring is equipped with the convex extending in circumference, the convex and the roll ring installation groove shape are matched and there is radial and axial interference fit.The utility model realizes the consideration of economy and durability by assembly structure, and reduces the instability of non-integral structure by structural design.

Description

Technical Field

[0001] This utility model relates to the field of steel rolling equipment technology, specifically to a cemented carbide assembled pinch roll. Background Technology

[0002] Pinch rolls are workpieces used in steel mill rolling lines to transport rolled steel bars. Currently, the most common pinch rolls have an overall ring structure, with guide grooves on the outer circular surface of the pinch roll, and R-keys for circumferential fixation are machined in the middle mounting hole of the pinch roll. The whole is mostly made of high-speed steel or hard alloy.

[0003] To increase the durability of pinch rolls and improve the steel throughput per shift, some pinch rolls are currently made of cemented carbide, such as utility model patent CN216027108U. Although cemented carbide has excellent physical properties such as heat resistance, hardness, and wear resistance, it has high density, poor toughness, and high cost. Pinch rolls made solely of cemented carbide have a significantly increased overall weight, which brings new performance problems to the shafts and motors used to drive the high-speed rotation of the pinch rolls in the original rolling mill stand. The risk of shaft breakage is relatively high, and the manufacturing cost is too high, making it impossible to achieve both economy and durability. Utility Model Content

[0004] To overcome the above problems, this utility model proposes a cemented carbide assembled pinch roller.

[0005] The technical solution adopted by this utility model is as follows: a cemented carbide assembled pinch roller includes a roller ring, a base, and a cover plate; the base and the cover plate are both stepped shaft structures, each divided into a coarse section and a fine section; the base and the cover plate are coaxially arranged and the fine sections are opposite each other, and are fixedly connected by fasteners, with the two fine sections joining to form a circumferentially extending roller ring mounting groove; the base and the cover plate are provided with an inner hole through the center; the roller ring is sleeved on the outside of the base and the cover plate, and the inner hole of the roller ring is provided with a circumferentially extending protrusion, the protrusion being adapted to the shape of the roller ring mounting groove and having a radial and axial interference fit.

[0006] Preferably, an axial gap is left between the end face of the base segment and the end face of the cover segment to provide space for deformation of the steel parts when the fasteners are pre-tightened.

[0007] Preferably, the axial clearance is greater than 0.5 mm before the fastener is tightened and less than 0.2 mm after the fastener is tightened, to ensure that the end face of the inner hole protrusion structure of the roller ring has an effective axial interference fit.

[0008] Preferably, the inner holes of the base and the cover plate are coaxially connected to form a mounting hole, and the inner wall of the mounting hole is provided with a keyway that extends axially and passes through the base and the cover plate to achieve reliable circumferential fixation with the drive shaft.

[0009] Preferably, the outer circumferential surface of the roller ring is provided with an annular groove with an arc-shaped cross-section and the arc of the cross-section matches the arc of the outer surface of the workpiece being clamped, thereby improving the stability of workpiece conveying; the minimum radial distance between the outer circumferential surface of the thick section of the base and the bottom surface of the annular groove is greater than 15mm, ensuring that the structural strength of the clamping roller remains reliable throughout the process from normal operation to scrap size.

[0010] Preferably, the hardness and wear resistance of the roller ring are higher than those of the base and the cover plate, while the toughness of the base and the cover plate is higher than that of the roller ring. The combination of two different materials makes the pinch roller both economical and durable.

[0011] Preferably, the fastener is a plurality of screws arranged circumferentially, the end face of the base is provided with a plurality of threaded holes circumferentially, and the end face of the narrow section of the cover plate is provided with a plurality of countersunk holes at corresponding positions. The threaded holes and countersunk holes are used to install the screws, thereby achieving reliable assembly of the base and the cover plate.

[0012] Preferably, the threaded hole is located between the outer peripheral surface and the inner hole surface of the base segment and the minimum distance from the outer surface of the segment is greater than 13mm, so as to avoid weakening the strength of the segment; the countersunk hole is coaxially arranged with the threaded hole.

[0013] Preferably, the radial width of the step between the thick and thin sections of the base or cover is greater than 18 mm to provide sufficient frictional contact area.

[0014] Preferably, the right-angled concave corners of the base and cover plate, as well as the right-angled concave corners of the inner hole of the roller ring, are provided with chamfered structures to eliminate the risk of assembly interference.

[0015] This utility model adopts a workpiece combination design of two materials. The stepped shaft base and the cover plate are connected to form a roller ring mounting groove. Combined with the radial and axial interference fit design of the roller ring protrusion, the reliability of torque transmission is enhanced and the slippage between the base or cover plate and the roller ring is avoided. While ensuring the high wear resistance of the roller ring, the high toughness of the base / cover plate is used to reduce the risk of overall fracture. Ultimately, the comprehensive performance improvement of the pinch roller is achieved, which is lightweight, highly wear-resistant and fracture-resistant, while controlling the manufacturing cost. Attached Figure Description

[0016] Figure 1 This is a side view of a cemented carbide assembled pinch roller according to the present invention; Figure 2 This is a cross-sectional view of a cemented carbide assembled pinch roller according to the present invention.

[0017] Figure label: 1-Roller ring, 2-Base, 3-Cover plate, 4-Keyway, 11-Annular groove, 21-First inner hole, 22-Threaded hole, 31-Second inner hole, 32-Counterhead hole. Detailed Implementation

[0018] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0019] like Figure 1 and Figure 2 As shown, a cemented carbide assembly pinch roll includes a roll ring 1, a base 2, and a cover plate 3. Both the base 2 and the cover plate 3 are stepped shaft structures, divided into a thicker section with a larger outer diameter and a thinner section. The base 2 and the cover plate 3 are coaxial, with their thinner sections facing each other and fixedly connected by screws. The two thinner sections abut together to form a circumferentially extending roll ring mounting groove. The roll ring mounting groove is formed by the outer circumferential surface of the thinner section of the base 2, the end face of the thicker section, the outer circumferential surface of the thinner section of the cover plate 3, and the end face of the thicker section. A through-hole of the same diameter is provided in the center of both the base 2 and the cover plate 3. The roll ring 1 is fitted onto the base 2 and the cover plate 3, with a certain radial interference fit. The inner hole of the roll ring 1 has a circumferentially extending protrusion, the shape of which matches the roll ring mounting groove formed by the thinner sections. The end faces of the thinner sections of the base 2 and the cover plate 3 do not directly contact each other, leaving a certain gap. This gap allows for deformation space of the steel components to allow for screw tightening, preventing the steel components of the base 2 and the cover plate 3 from completely sticking together and losing the screw tightening effect. Before the screws are tightened, the gap width is 0.6mm. After the screws are tightened, the gap shrinks to less than 0.2mm, thereby creating an interference fit on the axial end face of the roller ring 1, which enhances the friction between the roller ring 1 and the base 2 and cover plate 3 during operation.

[0020] The base 2 has a first inner hole 21 in the center, and the cover plate 3 has a second inner hole 31 in the center. The diameters of the first inner hole 21 and the second inner hole 31 are the same. The inner holes of the base 2 and the cover plate 3 are connected to form a mounting hole. A keyway 4 is machined in the mounting hole, passing through the inner holes of the base 2 and the cover plate 3. The keyway 4 is used to axially fix the output shaft of the external drive device. The base 2 and the cover plate 3 are made of alloy steel, and the roller ring 1 is made of hard alloy. Hard alloy has greater hardness and better wear resistance than alloy steel, while alloy steel has better toughness. This effectively solves the problems of short service life of high-speed steel pinch rolls and easy breakage and high cost of hard alloy pinch rolls.

[0021] The outer circumferential surface of the roller ring 1 is provided with an annular groove 11. The cross-section of the annular groove 11 is arc-shaped, and the curvature of the cross-section of the annular groove 11 matches the curvature of the outer surface of the product being clamped. The maximum outer diameter of the outer circumferential surface of the roller ring 1 is 280-300mm, where 280mm is the required diameter for the scrapped roller. The scrapped roller diameter is the maximum outer diameter of the roller ring 1 when the clamping roller is worn to the point of scrapping. The diameter of the thin section of the base 2 and the thin section of the cover plate 3 is 185mm, and the diameter of the thick section is 225mm. The inner diameter of the base 2 and the cover plate 3 is 75mm. The lengths of the thick sections of the base 2 and the cover plate 3 are the same, both 20mm. This distance is the space for the force to be applied after the screws of the base 2 and the cover plate 3 are tightened. If it is too short, the base 2 will deform after the screws are tightened. The diameter of the thick section is designed based on the scrapped roller diameter. The design goal is that the minimum distance between the outer circumferential surface of the thick section and the bottom surface of the annular groove 11 after the clamping roller is worn to the point of scrapping is greater than 15mm, so that the clamping roller reaches the required strength level. The radius between the thick and thin sections of the base 2 or cover plate 3 is at least 18mm apart. This distance determines the contact area between the base 2 / cover plate 3 and the roller ring 1. If it is too small, it will result in insufficient friction. In this embodiment, it is 20mm.

[0022] The base 2 has eight through-holes 22 with M12 threads circumferentially arranged on its end face. The radial position of the threaded holes 22 is between the outer surface of the thin section of the base 2 and the inner surface of the hole, and is biased towards the outer surface of the thin section. At the same time, the minimum radial distance between the threaded holes 22 and the outer surface of the thin section of the base 2 is not less than 13mm. The cover plate 3 has eight through-holes 32 corresponding to the threaded holes 22 of the base 2. Screws are screwed into the threaded holes 22 through the countersunk holes 32 to press and fix the base 2, cover plate 3 and roller ring 1. Due to process limitations, material residue or burrs often appear at the right angles of the steel parts because the tool cannot completely cut them. Therefore, in this embodiment, the right angle concave corners of the base 2 and cover plate 3 and the right angle concave corners of the roller ring 1 are further cleaned to prevent the roller ring 1 from not being fully installed due to incomplete cutting.

[0023] In this embodiment, the manufacturing and assembly process of the pinch roller includes the following steps: S1: Machining roller ring 1, base 2 and cover plate 3 respectively. The first inner hole 21 of base 2 and the second inner hole 31 of cover plate 3 are reserved with a diameter margin of 1mm and machined with a diameter of 74mm. Keyway 4 is not machined. S2: Apply glue to the outer side of the base 2 and the cover plate 3 and the inner side of the roller ring 1. Then, install the roller ring 1 on the outside of the base 2 through a hot assembly process. Install the cover plate 3 before the roller ring 1 cools down. Tighten the screws to 210 NM to give the roller ring 1 sufficient axial interference. S3: After assembly, the first inner hole 21 of the base 2 and the second inner hole 31 of the cover plate 3 are precision machined to a preset diameter of 75mm by internal grinding to ensure that there are no steps at the joint. After the inner hole is precision machined, the keyway 4 is machined.

[0024] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A cemented carbide assembly pinch roll, comprising a roll ring, a base, and a cover plate; the base and the cover plate are both stepped shaft structures, each divided into a coarse section and a fine section; the base and the cover plate are coaxially arranged with the fine sections opposite each other, and are fixedly connected by fasteners, with the two fine sections joined to form a circumferentially extending roll ring mounting groove; the base and the cover plate are provided with an inner hole through the center; the roll ring is sleeved on the outside of the base and the cover plate, and the inner hole of the roll ring is provided with a circumferentially extending protrusion, the protrusion being adapted to the shape of the roll ring mounting groove and having a radial and axial interference fit.

2. The cemented carbide assembly pinch roll according to claim 1, characterized in that, An axial gap is left between the end face of the base segment and the end face of the cover plate segment.

3. The cemented carbide assembly pinch roll according to claim 2, characterized in that, The axial clearance is greater than 0.5mm before the fastener is tightened, and less than 0.2mm after the fastener is tightened.

4. The cemented carbide assembly pinch roll according to claim 1, characterized in that, The inner holes of the base and the cover plate are coaxially connected to form a mounting hole, and the inner wall of the mounting hole is provided with a keyway that extends axially and passes through the base and the cover plate.

5. The cemented carbide assembly pinch roll according to claim 1, characterized in that, The outer circumferential surface of the roller ring is provided with an annular groove with an arc-shaped cross-section, and the arc of the cross-section matches the arc of the outer surface of the workpiece being clamped; the minimum radial distance between the outer circumferential surface of the thick section of the base and the bottom surface of the annular groove is greater than 15mm.

6. The cemented carbide assembly pinch roll according to claim 1, characterized in that, The roller ring has higher hardness and wear resistance than the base and the cover plate, while the base and the cover plate have higher toughness than the roller ring.

7. The cemented carbide assembly pinch roll according to claim 1, characterized in that, The fastener is a number of screws arranged circumferentially. The end face of the base is provided with a number of threaded holes circumferentially. The end face of the narrow section of the cover plate is provided with a number of countersunk holes at corresponding positions. The threaded holes and countersunk holes are used to install the screws.

8. The cemented carbide assembly pinch roll according to claim 7, characterized in that, The threaded hole is located between the outer peripheral surface and the inner surface of the base segment, and the minimum distance between the threaded hole and the outer surface of the segment is greater than 13mm; the countersunk hole is coaxial with the threaded hole.

9. The cemented carbide assembly pinch roll according to claim 1, characterized in that, The radial width of the step between the thick and thin sections of the base or cover plate is greater than 18 mm.

10. The cemented carbide assembly pinch roll according to claim 1, characterized in that, The base and cover plate have right-angle concave corners, as well as the right-angle concave corners of the inner hole of the roller ring, which are equipped with corner clearing structures.

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