A spline type carbon fiber pipe coupling for heavy machine tools

Abstract

The application provides a spline type carbon fiber pipe coupling for heavy machine tools, which comprises a carbon fiber pipe assembly, two piece involute tooth inner spline sleeves and a central inner cooling assembly; the carbon fiber pipe assembly comprises a carbon fiber shaft pipe and metal flanges embedded in two ends of the carbon fiber shaft pipe respectively, the carbon fiber shaft pipe and the metal flanges are integrally formed after mixed coupling and solidification, thereby forming a permanent coupling structure; one end of the involute tooth inner spline sleeve is provided with involute inner spline teeth, which are used for matched connection with outer splines of a machine tool spindle or a transmission shaft, and the other end is a flange connection part, which is detachably fastened and connected with an end surface of the metal flange of the corresponding end through high-strength hinge hole bolts; the central inner cooling assembly comprises an inner cooling pipe and two piece locking nuts. The application replaces the diaphragm connection with involute splines, cooperates with a pre-stretching central inner cooling structure, and realizes the integration and cooperation of high torsional stiffness, high speed adaptability and structural simplification.

Description

Technical Field

[0001] This invention relates to the field of heavy-duty machine tool transmission technology, and in particular to a splined carbon fiber tube coupling for heavy-duty machine tools. Background Technology

[0002] As the mother machines of industry, heavy-duty machine tools are experiencing rapid and continuous growth in demand in key sectors such as aerospace, defense science and technology, rail transportation, and shipbuilding. The technological level of their core functional components often determines the key performance indicators of machine tool products. In the main motion transmission chain of heavy-duty machine tools, the spindle coupling is a key functional component connecting the spindle motor and the spindle, and its performance directly affects the machining accuracy, cutting efficiency, and operational stability of the machine tool.

[0003] Currently, most carbon fiber tube couplings on the market adopt a diaphragm-type connection structure, where both ends of the carbon fiber tube are connected to the main shaft and drive shaft via metal diaphragm assemblies. While this type of diaphragm-type carbon fiber tube coupling has a certain degree of correction capability, it suffers from the following drawbacks: First, the torsional stiffness of the diaphragm connection structure is limited, and the diaphragm undergoes significant elastic deformation under high torque conditions, making it difficult to meet the stringent requirements of high-precision heavy-duty machine tools for transmission stiffness. Second, the diaphragm assembly is at risk of fatigue failure under long-term alternating loads, affecting the coupling's service life and reliability. Third, the axial dimension of the diaphragm coupling is large, making it difficult to arrange within the limited installation space of the ram in heavy-duty machine tools. Furthermore, the central cooling function of existing carbon fiber tube couplings typically requires an intermediate support on the internal cooling pipe, resulting in a complex structure, cumbersome manufacturing and assembly processes, and the intermediate support generates additional unbalanced mass during high-speed rotation, limiting the coupling's maximum operating speed. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a splined carbon fiber tube coupling for heavy-duty machine tools.

[0005] The specific technical solution is as follows: A splined carbon fiber tube coupling for heavy-duty machine tools includes a carbon fiber tube assembly, two involute toothed internal spline sleeves, and a central internal cooling assembly. The carbon fiber tube assembly includes a carbon fiber shaft tube and metal flanges embedded at both ends. The carbon fiber shaft tube and the metal flanges are integrally formed after mixing and curing to form a permanent coupling connection structure. One end of the involute toothed internal spline sleeve is provided with involute internal spline teeth for connecting with the external spline of the machine tool spindle or drive shaft. The other end is a flange connection part, which is detachably fastened to the end face of the corresponding metal flange by bolts through high-strength reamed holes. The central internal cooling assembly includes an internal cooling tube and two locking nuts. The internal cooling tube is coaxially inserted through the center of the carbon fiber tube assembly, and its two ends pass through the metal flanges at both ends. The locking nuts apply an axial pre-tension force to the internal cooling tube, so that the internal cooling tube remains axially tensioned without intermediate support.

[0006] Optionally, after the carbon fiber shaft tube and the metal flange are mixed, connected, cured, and demolded, a stop mounting structure is formed on the outer end face of the metal flange by CNC machining. The stop mounting structure cooperates with the stop of the flange connection part of the involute toothed inner spline sleeve to ensure the connection interface accuracy between the metal flange and the involute toothed inner spline sleeve.

[0007] Optionally, the tooth profile of the involute internal spline is an involute tooth profile with a pressure angle of 30°, and the involute internal spline is in a tooth flank centering fit with the external spline of the machine tool spindle or transmission shaft.

[0008] Optionally, the middle section of the carbon fiber shaft tube is a thin-walled circular tube structure with a uniform cross-section.

[0009] Optionally, the high-strength reamed hole bolt is a 12.9 grade reamed hole bolt, and the end face of the metal flange is provided with a number of reamed screw holes corresponding to the number of reamed hole bolts.

[0010] Optionally, an anti-loosening washer is provided between the locking nut and the outer end face of the metal flange, and the axial pre-tension force applied by the locking nut to the inner cooling pipe prevents the inner cooling pipe from axially loosening at the highest design speed of the coupling.

[0011] Optionally, both ends of the internal cooling pipe are provided with external thread sections that mate with the locking nut.

[0012] Optionally, the metal flange is made of steel.

[0013] Optionally, the metal flange connection portion has 6 to 8 bolts with reamed holes evenly distributed along its circumference.

[0014] Optionally, the coupling is integrally installed inside the slide of the heavy-duty machine tool, and the two ends of the coupling are respectively connected to the main spindle and the drive shaft of the heavy-duty machine tool through the involute toothed internal spline sleeve. The central internal cooling assembly provides a central gas-liquid transmission channel for the main spindle of the heavy-duty machine tool.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention replaces conventional diaphragm connections with involute spline connections at both ends of the carbon fiber tube assembly. The involute spline's uniform tooth contact, high load-bearing capacity, and self-centering properties, combined with the lightweight and high-rigidity characteristics of the carbon fiber tube, significantly improve the overall torsional stiffness of the coupling. Simultaneously, the axial sliding capability of the spline fit simplifies installation, making it particularly suitable for high-speed, high-rigidity applications in high-precision heavy-duty machine tools. The central internal cooling assembly employs a pre-tensioned structure with locking nuts at both ends, eliminating the intermediate support, simplifying the assembly process, and removing the additional unbalanced mass introduced by the intermediate support, thus improving the coupling's high-speed operational stability and reliability. The internal spline sleeve and carbon fiber tube assembly are detachably connected using high-strength reamed bolts. After spline tooth wear, individual maintenance and replacement are possible without replacing the entire coupling, reducing the total life-cycle cost. Attached Figure Description

[0016] Figure 1 This is an axial cross-sectional view of the splined carbon fiber tube coupling for heavy-duty machine tools according to an embodiment of the present invention.

[0017] In the diagram: 1. Involute toothed internal spline sleeve; 2. Metal flange; 3. Carbon fiber shaft tube; 4. Internal cooling tube; 5. Bolt for reamed hole; 6. Locking nut. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0020] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0023] like Figure 1 As shown in this embodiment, a splined carbon fiber tube coupling for heavy-duty machine tools includes a carbon fiber tube assembly, two involute toothed internal spline sleeves 1, and a central internal cooling assembly. The carbon fiber tube assembly includes a carbon fiber shaft tube 3 and metal flanges 2 embedded at both ends. The carbon fiber shaft tube 3 and the metal flanges 2 are integrally formed after mixing, connecting, and curing to form a permanent coupling connection structure. After demolding, the outer end face of the metal flanges 2 is machined with a stop to ensure the accuracy of the connection interface, and evenly distributed reamed screw holes are machined on the end face of the metal flanges 2. The metal flanges 2 are preferably made of steel. The middle section of the carbon fiber shaft tube 3 is a thin-walled circular tube structure with a uniform cross-section, forming a lightweight transmission structure as a whole.

[0024] like Figure 1 As shown, there are two involute toothed internal spline sleeves 1, respectively located at both ends of the coupling. One end of the involute toothed internal spline sleeve 1 is provided with involute internal spline teeth, used for mating with the external spline on the spindle or drive shaft of a heavy machine tool. The spline tooth profile adopts a 30° pressure angle involute tooth profile, with a module preferably of 3mm, and the number of teeth is determined according to the required torque. Compared with rectangular splines, 30° involute splines have the characteristics of self-centering, uniform tooth surface contact, and high load-bearing capacity. Its tooth flank centering mating method allows the coupling to automatically compensate for small radial deviations during high-speed rotation, ensuring transmission accuracy. The other end of the involute toothed internal spline sleeve 1 is a flange connection part. The end face of the flange connection part is provided with a stop groove that mates with the stop mounting structure of the metal flange 2. A detachable fastening connection is formed with the end face of the metal flange 2 through 12.9 grade high-strength reamed bolts 5. Figure 1As shown, the smooth shank of the bolt 5 for reamed holes bears the shear load, while the threaded section only provides axial preload, thus ensuring high rigidity and fatigue resistance of the connection. Six to eight bolts 5 for reamed holes are evenly distributed circumferentially along the flange connection, the specific number determined by the transmitted torque. This detachable connection method allows the involute toothed internal spline sleeve 1 to be individually disassembled and replaced after long-term wear of the spline teeth 11, without the need to scrap the entire coupling.

[0025] like Figure 1 As shown, the central internal cooling assembly includes an internal cooling tube 4 and two locking nuts 6. The internal cooling tube 4 is coaxially inserted through the center of the carbon fiber tube assembly, with its two ends passing through the central through-holes of the metal flanges 2 at both ends. Each end of the internal cooling tube 4 has an external thread section that mates with the internal threads of the locking nuts 6. Because the internal cooling tube 4 is in a pre-tensioned state, it has sufficient rigidity and self-supporting capacity, eliminating the need for any intermediate support components inside the carbon fiber tube assembly. The metal flanges 2 at both ends provide radial positioning at the ends of the internal cooling tube 4, while the gap between the central through-hole of the metal flange 2 and the outer wall of the internal cooling tube 4 prevents the pre-tensioned state of the internal cooling tube 4 from being constrained by the metal flanges 2. This pre-tensioned structure eliminates the additional unbalanced mass caused by intermediate supports, simplifies the assembly process, and improves the operational stability of the coupling under high-speed rotation.

[0026] like Figure 1 As shown, the coupling in this embodiment is integrally installed within the ram of a heavy-duty gantry machining center. One end of the coupling is connected to the external spline of the machine tool spindle via an involute toothed internal spline sleeve 1, and the other end is connected to the external spline of the drive shaft via another involute toothed internal spline sleeve 1. During installation, the axial sliding capability of the involute spline is utilized to push the coupling axially into the ram cavity, allowing the involute toothed internal spline sleeves 1 at both ends to mesh with the external splines of the spindle and drive shaft, respectively, eliminating the need for complex axial alignment adjustments required for diaphragm couplings. During operation, the spindle motor transmits torque to the coupling via the drive shaft, which then transmits it to the spindle via the carbon fiber shaft tube 3. Simultaneously, the central internal cooling assembly supplies coolant or compressed air to the spindle through the internal cooling channel of the internal cooling pipe 4. Under high-speed rotation conditions, the lightweight and high-rigidity characteristics of the carbon fiber tube assembly, combined with the high centering accuracy of the involute spline, enable the coupling to maintain stable operation, meeting the high rigidity and high-speed requirements of high-precision heavy machine tools for the main drive system.

[0027] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A splined carbon fiber tube coupling for heavy-duty machine tools, characterized in that, The system includes a carbon fiber tube assembly, two involute toothed internal spline sleeves, and a central internal cooling assembly. The carbon fiber tube assembly comprises a carbon fiber shaft and metal flanges embedded at both ends. The carbon fiber shaft and the metal flanges are integrally formed after being mixed, connected, and cured to form a permanent coupling connection structure. One end of the involute toothed internal spline sleeve is provided with involute internal spline teeth for connecting with the external spline of a machine tool spindle or drive shaft. The other end is a flange connection part, which is detachably fastened to the end face of the corresponding metal flange by bolts through high-strength reamed holes. The central internal cooling assembly includes an internal cooling tube and two locking nuts. The internal cooling tube is coaxially inserted through the center of the carbon fiber tube assembly, with its two ends passing through the metal flanges at both ends. The locking nuts apply an axial pre-tension force to the internal cooling tube, keeping it axially tensioned without intermediate support.

2. The splined carbon fiber tube coupling for heavy-duty machine tools according to claim 1, characterized in that, After the carbon fiber shaft tube and the metal flange are mixed, connected, cured, and demolded, a stop installation structure is formed on the outer end face of the metal flange by CNC machining. The stop installation structure cooperates with the stop of the flange connection part of the involute toothed inner spline sleeve to ensure the connection interface accuracy between the metal flange and the involute toothed inner spline sleeve.

3. The splined carbon fiber tube coupling for heavy-duty machine tools according to claim 2, characterized in that, The involute internal spline tooth profile is a 30° pressure angle involute tooth profile, and the involute internal spline tooth and the external spline of the machine tool spindle or transmission shaft are tooth flank centering fit.

4. The splined carbon fiber tube coupling for heavy-duty machine tools according to claim 1, characterized in that, The middle section of the carbon fiber shaft tube is a thin-walled circular tube structure with a uniform cross-section.

5. The splined carbon fiber tube coupling for heavy-duty machine tools according to claim 1, characterized in that, The high-strength reamed bolt is a grade 12.9 reamed bolt, and the end face of the metal flange is provided with a number of reamed bolt holes corresponding to the number of reamed bolts.

6. The splined carbon fiber tube coupling for heavy-duty machine tools according to claim 1, characterized in that, An anti-loosening washer is provided between the locking nut and the outer end face of the metal flange. The axial pre-tension force applied by the locking nut to the inner cooling pipe prevents the inner cooling pipe from axially loosening at the highest design speed of the coupling.

7. The splined carbon fiber tube coupling for heavy-duty machine tools according to claim 6, characterized in that, The internal cooling pipe has external threaded sections at both ends that mate with the locking nut.

8. The splined carbon fiber tube coupling for heavy-duty machine tools according to claim 1, characterized in that, The metal flange is a steel component.

9. The splined carbon fiber tube coupling for heavy-duty machine tools according to claim 1, characterized in that, The metal flange has 6 to 8 bolts with reamed holes evenly distributed along the circumference of the connecting part.

10. The splined carbon fiber tube coupling for heavy-duty machine tools according to claim 1, characterized in that, The coupling is installed as a whole in the slide of the heavy machine tool. The two ends of the coupling are respectively connected to the main spindle and the drive shaft of the heavy machine tool through the involute toothed internal spline sleeve. The central internal cooling assembly provides a central gas-liquid transmission channel for the main spindle of the heavy machine tool.

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