A press quench mandrel

Abstract

The utility model discloses a kind of pressure quenching mandrels, including mandrel body, elastic connecting piece and radial movement driving part, mandrel body includes multiple mandrel petals, the mandrel petals are circumferentially spliced into the cylindrical mandrel body, the first recess of inverted cone is provided at the top of mandrel body, the bottom of mandrel body is provided with the via hole communicated with the first recess;The elastic connecting piece is sleeved in the mandrel body, for multiple the mandrel petals are used for multiple the mandrel petals are tightly fixed;Radial movement driving part is arranged in the first recess, when radial movement driving part moves along the axial direction of mandrel body, it can simultaneously extrude all the radial movement of mandrel petals to change the external dimension of mandrel body, and the bottom end of radial movement driving part can be extended from the via hole and be connected with the pull rod of mould.This pressure quenching mandrel structure is simplified, and outer diameter size can be conveniently and accurately adjusted to adapt to different specifications workpieces.

Description

Technical Field

[0001] This utility model relates to the field of mechanical parts processing technology, specifically to a pressure-quenched mandrel. Background Technology

[0002] In the heat treatment process of mechanical manufacturing, pressure hardening is a key process to prevent deformation of parts. This process requires using a mandrel to hold the inner bore of the workpiece (such as a bearing ring, gear ring, etc.) in place, followed by cooling. Traditionally, mandrels that achieve expandable / contractable functionality typically employ one of the following two structural forms: One type is the wedge-linkage combination structure. This structure converts axial movement into radial expansion through a complex combination of multiple wedges, links, pins, and other parts. Its inherent drawbacks are: the large number of parts and complex assembly relationships lead to high manufacturing costs; assembly gaps and cumulative errors exist between multiple kinematic pairs, making it difficult to achieve highly consistent synchronous movement of each tightening point, making debugging difficult, and the accuracy decays significantly due to wear after long-term use.

[0003] The second type is the multi-lobed expansion sleeve outer mold structure. While this structure can provide uniform tightening force, the overall structure is bulky and the manufacturing process is complex. More importantly, its radial dimension is usually fixed or has a limited adjustment range, making it a dedicated design for specific shafts. When machining workpieces with different inner diameters, the entire mandrel mold must be replaced. This not only increases mold inventory costs but also leads to excessively long changeover times on the production line, severely restricting production efficiency and flexible production capabilities. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the technical problem to be solved by this utility model is to provide a new type of pressure quenching mandrel with a simplified structure, which can conveniently and accurately adjust the outer diameter to adapt to workpieces of different specifications.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a pressure-quenched mandrel, comprising: The mandrel body includes multiple mandrel segments, which are circumferentially spliced ​​to form a cylindrical mandrel body. The top of the mandrel body is provided with an inverted conical first groove, and the bottom of the mandrel body is provided with a through hole communicating with the first groove. An elastic connector is sleeved on the mandrel body and used to clamp and fix the multiple mandrel petals. A radial movement drive is disposed in the first groove. When the radial movement drive moves along the axial direction of the mandrel body, it can simultaneously squeeze all the mandrel petals radially, thereby changing the external dimensions of the mandrel body. The bottom end of the radial movement drive can extend out from the through hole and connect to the pull rod of the mold.

[0006] Furthermore, the elastic connector is a spring coil.

[0007] Furthermore, the radial movement drive includes a drive rod and an inverted conical extrusion block. The extrusion block is sleeved and fixed on the top of the drive rod. The drive rod passes through the first groove and the through hole in sequence and is connected to the pull rod of the mold. During the axial movement of the drive rod, the sidewall of the extrusion block drives the mandrel to move radially outward by extruding the inner wall of the mandrel.

[0008] Furthermore, the drive rod is a threaded rod, and the through hole is provided with an internal thread that mates with the external thread on the drive rod.

[0009] Furthermore, the bottom end of the drive rod is provided with a threaded hole, which can be threadedly connected to the pull rod of the mold.

[0010] Furthermore, the mandrel body is divided into a large head and a small head in the axial direction, and the outer diameter of the large head is larger than the outer diameter of the small head.

[0011] Furthermore, the outer wall of the mandrel body is provided with a plurality of limiting grooves spaced along the axial direction, and the elastic connector is disposed in the limiting grooves.

[0012] Furthermore, the outer wall of the mandrel body is provided with a plurality of oil grooves that extend axially at circumferential intervals.

[0013] The beneficial effects of this utility model are: The pressure-hardened mandrel described above has at least the following advantages: 1. This technical solution consists of only three core components, completely eliminating the numerous complex transmission components such as wedges and connecting rods found in traditional structures. This significant reduction in the number of parts directly leads to lower material, processing, and assembly costs, while simultaneously improving product reliability.

[0014] 2. By using a single radial movement drive component moving axially, the inclined plane principle or direct drive can simultaneously and evenly compress all circumferentially distributed mandrel segments, achieving synchronous radial movement. This design fundamentally eliminates the asynchronous movement problems caused by fit clearances in traditional multi-component drives, ensuring the roundness and consistency of mandrel expansion, thereby guaranteeing workpiece machining accuracy. No repeated disassembly and adjustment are required during debugging, significantly improving debugging efficiency.

[0015] 3. Because the external dimensions of the mandrel body can be continuously and precisely adjusted through the axial displacement of the drive components, a single mandrel can cover a variety of workpiece specifications within a certain size range. This greatly reduces the number of spare mandrels on the production line, solves the drawbacks of "dedicated mandrels for dedicated purposes," and shortens changeover time, making it particularly suitable for flexible production needs with multiple varieties and small batches. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of this utility model, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0017] Figure 1 A schematic diagram of a pressure-quenched mandrel provided in an embodiment of the present invention; Figure 2 for Figure 1 An exploded view of the pressure-quenched mandrel shown. Figure 3 for Figure 1 Another angle view of the exploded view of the pressure-quenched mandrel shown. Figure label: 100, mandrel body; 110, mandrel petal; 120, first groove; 130, through hole; 140, limiting groove; 150, oil groove; 200, elastic connector; 300, radial movement drive; 310, drive rod; 320, extrusion block. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention; therefore, the invention is not limited to the specific embodiments disclosed below.

[0019] Please see Figures 1 to 3 This utility model provides a pressure quenching mandrel, including a mandrel body 100, an elastic connector 200 and a radial movement drive 300.

[0020] The mandrel body 100 is composed of multiple mandrel segments 110 circumferentially joined together to form a complete cylindrical structure. This segmented design is the basis for achieving size adjustment. At the top of the mandrel body 100, an inverted conical first groove 120 is machined; at its bottom, a through hole 130 communicating with the first groove 120 is provided.

[0021] The elastic connector 200 is tightly fitted onto the outside of the mandrel body 100, and uses its own elastic contraction force to keep the multiple independent mandrel segments 110 always taut towards the center, so that they can be tightly spliced ​​together to form a complete cylinder in the initial state. This ensures that the mandrel body 100 can maintain a certain basic size and roundness in the non-working state.

[0022] The radial movement drive 300 is disposed within the first groove 120 at the top. When it moves axially along the mandrel body 100, it simultaneously and uniformly compresses all the mandrel segments 110, forcing them to overcome the constraint force of the elastic connector 200 and synchronously move radially outward, thereby increasing the outer diameter of the mandrel body 100. After operation, when the radial movement drive 300 retracts, the rebound force of the elastic connector 200 immediately pulls the mandrel segments 110 back to their initial position, achieving contraction. Furthermore, the bottom end of the radial movement drive 300 can extend from the through hole 130 for connection with the mold's tie rod.

[0023] During operation, the pull rod of the mold moves, pulling or pushing the radial movement drive 300 axially. The drive compresses the mandrel flap 110, causing it to expand radially, thereby tightening the working inner hole to be machined. After the quenching process is completed, the pull rod moves in the opposite direction, the drive retracts, and the elastic connector 200 resets the mandrel flap 110, restoring the overall size of the mandrel and facilitating the removal of the workpiece.

[0024] Compared to the complex structures mentioned in the background art, such as the "wedge block linkage combination" or "multi-lobed expansion sleeve type outer mold," this pressure quenching mandrel consists of only three main parts, significantly reducing the number of parts and resulting in an extremely compact structure. This directly leads to a reduction in material costs as well as processing and assembly costs.

[0025] When the size of the mandrel body 100 needs to be changed, a single drive component can achieve synchronous and equal-diameter movement of all mandrel segments 110, completely avoiding the inconsistency in accuracy caused by the misalignment of multiple components in traditional structures. No repeated disassembly and assembly is required during debugging, greatly saving debugging time and labor costs.

[0026] In this embodiment, the elastic connector 200 is a spring coil, which provides a uniform radial clamping force.

[0027] In this embodiment, the radial movement drive 300 includes a drive rod 310 and an inverted conical extrusion block 320. The extrusion block 320 is fixedly fitted onto the top of the drive rod 310. The drive rod 310 passes sequentially from top to bottom through the first groove 120 and the bottom through hole 130, and its end is used to connect with the pull rod of the mold.

[0028] When the drive rod 310 is driven upward by the pull rod, the inverted conical extrusion block 320 moves upward into the inverted conical first groove 120. Due to the inclined plane effect, the sidewall of the extrusion block 320 generates a huge outward radial force on the inner wall of the mandrel petals 110 surrounding it, forcing all mandrel petals 110 to move outward radially in sync, thus achieving expansion.

[0029] The inclined plane mechanism amplifies the axial force, allowing a larger radial expansion force to be obtained with a smaller axial tension. In addition, the simultaneous driving of all circumferentially distributed mandrel segments 110 by an inverted cone ensures the roundness and consistency of the expansion, resulting in high machining accuracy.

[0030] In practical implementation, the drive rod 310 can be designed as a threaded rod, and an internal thread is provided in the through hole 130 to match it. By rotating the pull rod of the mold (or the drive rod 310 itself), the rotational motion is converted into the precise axial linear motion of the drive rod 310 through the transmission of the threaded pair.

[0031] Threaded drives have a self-locking function, maintaining their current position without external force. This ensures the mandrel remains highly stable under tension, preventing it from retracting due to internal workpiece pressure and guaranteeing the safety and stability of the machining process. Threaded drives allow for precise adjustments down to the micrometer level, facilitating accurate control of the mandrel's expansion dimensions.

[0032] In practical implementation, by reasonably setting the inclination angle of the conical surface and the pitch of the thread, the radial movement of the mandrel can be precisely controlled. For example, by setting the included angle to 70° and with a pitch of 0.2mm, a precise feed of 0.05mm is achieved for each rotation of the mandrel. In this embodiment, the drive rod 310 is connected to the pull rod by providing a threaded hole at the bottom end of the drive rod 310, into which the pull rod of the mold can be directly screwed for connection. This method facilitates quick and detachable connection.

[0033] As a preferred embodiment, the mandrel body 100 is designed in the axial direction as two sections with different diameters: a large head and a small head, with the outer diameter of the large head being larger than that of the small head.

[0034] This structural design allows a single mandrel to simultaneously correspond to sections of different diameters on a workpiece, expanding the range of workpieces to which a single mandrel is applicable, reducing the need for stockpiling mandrels of different specifications in production, and achieving "one shaft for multiple uses".

[0035] In addition, in this embodiment, multiple limiting grooves 140 are spaced axially on the outer wall of the mandrel body 100. The elastic connector 200 (spring ring) is installed within these limiting grooves 140. The limiting grooves 140 provide axial positioning for the spring ring. This effectively prevents the spring ring from axially shifting or even falling off during mandrel expansion, contraction, or equipment vibration, ensuring operational reliability. It also ensures that the elastic force is applied along a predetermined position, resulting in more uniform force distribution on the mandrel petals 110 and more accurate resetting.

[0036] Furthermore, in this embodiment, a plurality of oil grooves 150 extending axially are machined at circumferential intervals on the circumferential outer wall of the mandrel body 100. During pressure quenching, quenching oil or cooling medium can flow through these grooves.

[0037] The oil tank 150 provides a flow channel for the cooling medium, allowing the medium to contact the inner wall of the workpiece more fully, carrying away heat and ensuring the uniformity and efficiency of quenching and cooling, thereby improving the heat treatment quality of the workpiece.

[0038] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A pressure-quenched mandrel, characterized in that, include: The mandrel body includes multiple mandrel segments, which are circumferentially spliced ​​to form a cylindrical mandrel body. The top of the mandrel body is provided with an inverted conical first groove, and the bottom of the mandrel body is provided with a through hole communicating with the first groove. An elastic connector is sleeved on the mandrel body and is used to clamp and fix the multiple mandrel segments together. A radial movement drive is disposed in the first groove. When the radial movement drive moves along the axial direction of the mandrel body, it can simultaneously squeeze all the mandrel petals radially, thereby changing the external dimensions of the mandrel body. The bottom end of the radial movement drive can extend out from the through hole and connect to the pull rod of the mold.

2. The pressure-quenched mandrel according to claim 1, characterized in that, The elastic connector is a spring coil.

3. The pressure-quenched mandrel according to claim 1, characterized in that, The radial movement drive includes a drive rod and an inverted conical extrusion block. The extrusion block is sleeved and fixed on the top of the drive rod. The drive rod passes through the first groove and the through hole in sequence and is connected to the pull rod of the mold. During the axial movement of the drive rod, the side wall of the extrusion block drives the mandrel to move radially outward by extruding the inner wall of the mandrel.

4. The pressure-quenched mandrel according to claim 3, characterized in that, The drive rod is a threaded rod, and the through hole is provided with an internal thread that mates with the external thread on the drive rod.

5. The pressure-quenched mandrel according to claim 3, characterized in that, The bottom end of the drive rod is provided with a threaded hole, which can be threadedly connected to the pull rod of the mold.

6. The pressure-quenched mandrel according to claim 1, characterized in that, The mandrel body is divided into a large head and a small head in the axial direction, and the outer diameter of the large head is larger than the outer diameter of the small head.

7. The pressure-quenched mandrel according to claim 1, characterized in that, The outer wall of the mandrel body is provided with multiple limiting grooves spaced along the axial direction, and the elastic connector is disposed in the limiting grooves.

8. The pressure-quenched mandrel according to claim 1, characterized in that, The outer wall of the mandrel body is provided with multiple oil grooves that extend axially at intervals along its circumference.

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