Centering fixture, machining tool and machining method for hollow shaft

Abstract

The present invention relates to the technical field of mechanical manufacturing, and disclosed are a centering fixture, machining tool and machining method for a hollow shaft. The centering fixture comprises a center rod; truncated-conical holes for matching tool centers are formed at two ends of the center rod; a first end of the center rod is provided with a truncated-conical boss for abutting against one end of the hollow shaft; a truncated-conical plug for abutting against the other end of the hollow shaft is movably fitted over a second end of the center rod; the truncated-conical plug and the center rod rotate synchronously; and a power pin for fitting a transmission rod of the tool centers is provided on the truncated-conical boss. The centering fixture for a hollow shaft provided by the present invention uses the friction force and clamping force between tool centers and a center rod of a centering fixture, and also increases a mechanical transmission mode by means of fitting of a power pin provided on the centering fixture and a transmission rod of the tool centers, thereby avoiding the problem of rotation delay of the hollow shaft during machining, and improving the finish machining effect of the hollow shaft.

Description

A centering fixture, machine tool, and machining method for hollow shafts.

[0001] This application claims priority to Chinese Patent Application No. 202410692068.4, filed on May 30, 2024, entitled "A centering fixture for hollow shafts, a machine tool and a machining method", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of mechanical manufacturing technology, and in particular to a centering fixture, machine tool and processing method for hollow shafts. Background Technology

[0003] The bogie, as the running gear of a monorail vehicle, bears the weight of the entire vehicle and its passengers, making it a critical component. Hollow shafts are mounted on the bogies, and running wheels are mounted on the hollow shafts, allowing the weight of the entire vehicle and its passengers to be transferred through the hollow shafts to the running wheels and ultimately to the track. The machining and assembly precision of the hollow shafts directly affects the vehicle's operational safety. During the precision machining of the hollow shafts, it is essential to ensure the concentricity of the precision turning and grinding processes to guarantee the overall machining accuracy of the hollow shafts.

[0004] In traditional finishing processes, centering fixtures are typically used to ensure concentricity during precision turning and grinding. Synchronous rotation between the centering fixture and the hollow shaft is achieved through friction between the fixture and the machine tool center. Friction transmission is then used between the machine tool center and the centering fixture, allowing the machine tool center to drive the hollow shaft. However, due to the relatively low friction between the machine tool center and the centering fixture, the transmission efficiency is low, resulting in sluggish rotation of the hollow shaft during machining, leading to poor finishing results.

[0005] Furthermore, since the centering fixture and the hollow shaft achieve synchronous rotation through friction, the synchronization between the hollow shaft and the centering fixture is poor.

[0006] Therefore, how to improve the finishing effect of hollow shafts while ensuring concentricity during the finishing process has become a technical problem that urgently needs to be solved by those skilled in the art.

[0007] Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide a centering fixture for hollow shafts, so as to improve the finishing effect of hollow shafts while ensuring the concentricity of hollow shafts during the finishing process.

[0009] Another object of the present invention is to provide a machine tool for machining hollow shafts with respect to the above-mentioned centering fixture.

[0010] Another object of the present invention is to provide a machining method for hollow shafts using the above-described centering fixture.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] A centering fixture for a hollow shaft, comprising:

[0013] The center rod has tapered holes at both ends for engaging with the machine tool center. The first end of the center rod has a tapered boss for pressing against one end of the hollow shaft. The second end of the center rod is movably fitted with a tapered plug for pressing against the other end of the hollow shaft. The tapered plug rotates synchronously with the center rod. The tapered boss has a power pin for engaging with the transmission rod of the machine tool center.

[0014] Optionally, in the above-mentioned centering fixture, the hollow shaft has a small-diameter end and a large-diameter end that are arranged opposite to each other. The tapered boss is used to press against the small-diameter end of the hollow shaft, and the tapered plug is used to press against the large-diameter end of the hollow shaft. The small-diameter end of the hollow shaft is provided with a keyway, and the side wall of the tapered boss is provided with a protrusion for cooperating with the keyway.

[0015] Optionally, in the above-mentioned centering fixture, the protrusion is provided with an extension extending out of the side wall of the tapered boss along the axial direction of the central rod, and a clearance space for inserting the hollow shaft is formed between the extension and the central rod.

[0016] Optionally, in the above-mentioned centering fixture, the central rod has a stepped shaft structure, and the outer diameter of the first end of the central rod is larger than the outer diameter of the second end of the central rod. The conical plug is slidably engaged with the second end of the central rod, and the second end of the central rod is provided with a locking mechanism for locking the conical plug from sliding.

[0017] Optionally, in the above-mentioned centering fixture, the locking mechanism includes a threaded portion disposed at the second end of the central rod and a fastener that engages with the threaded portion, the fastener being used to abut against the conical plug.

[0018] Optionally, in the above-mentioned centering fixture, both the fastener and the tapered plug are provided with a central hole for the second end of the central rod to pass through.

[0019] A machine tool for machining hollow shafts includes a chuck and a machine tool center disposed on the chuck. The machine tool center is provided with a transmission rod for cooperating with a centering fixture, wherein the centering fixture is a centering fixture for hollow shafts as described in any of the preceding claims.

[0020] Optionally, in the above-mentioned machine tool, the transmission rod has an L-shaped structure, and one end of the transmission rod is fixed to the side wall of the machine tool tip, while the other end of the transmission rod is used to abut against the power pin of the centering fixture.

[0021] A method for machining hollow shafts, comprising the steps of:

[0022] Rough machining is performed on the blank round steel tube to form a rough hollow shaft. The rough hollow shaft includes a threaded end and a frame mating end. The threaded end is provided with a keyway, and an annular protrusion is provided between the threaded end and the frame mating end.

[0023] The finishing process involves using a centering fixture for hollow shafts as described in any of the preceding descriptions to form a finished hollow shaft, wherein the finishing process includes precision turning and precision grinding.

[0024] Optionally, in the above processing method, the roughing step specifically includes:

[0025] The first end of the blank round steel pipe is machined to form the frame mating end;

[0026] To machine the threaded end, the blank round steel tube is flipped over, and the second end of the blank round steel tube is machined to form the threaded end.

[0027] The keyway is formed by machining the threaded end of the blank round steel pipe.

[0028] Optionally, in the above processing method, a further step is included between the roughing step and the finishing step:

[0029] The coarse hollow shaft is transported to the finishing location using storage and transportation equipment.

[0030] Optionally, in the above processing method, the storage and transportation fixture includes at least one fixture frame, on which a first support portion for supporting the threaded end of the coarse hollow shaft and a second support portion for supporting the frame mating end of the coarse hollow shaft are respectively provided. Both the first support portion and the second support portion are respectively provided with a V-shaped notch that mates with the end of the coarse hollow shaft.

[0031] Optionally, in the above processing method, the tooling frame is provided with a forklift sleeve; and / or,

[0032] The tooling frame is equipped with a lifting hook; and / or,

[0033] The inner wall of the V-shaped notch is provided with an elastic gasket.

[0034] Optionally, in the above processing method, the tooling frame includes a first crossbeam and a second crossbeam arranged in parallel, there are multiple first support parts, and each of the first support parts is distributed at intervals on the first crossbeam, and the second support parts are arranged on the second crossbeam in a one-to-one correspondence with the first support parts.

[0035] Optionally, in the above processing method, an intermediate crossbeam is arranged parallel to the first crossbeam and the second crossbeam, and an elastic support member corresponding to the first support part is provided on the intermediate crossbeam. The elastic support member is provided with an annular groove that cooperates with the annular protrusion of the coarse hollow shaft.

[0036] Optionally, in the above processing method, the tooling frame further includes a support base for supporting the storage and transportation tooling. The support base has a first end and a second end that are disposed opposite to each other. The first end of the support base is provided with a connecting pin, and the second end of the support base is provided with a connecting sleeve for engaging with the connecting pin of the adjacent tooling frame.

[0037] The centering fixture for hollow shafts provided by this invention achieves automatic centering between the centering fixture and the hollow shaft by passing a central rod through the central through hole of the hollow shaft, with a tapered boss at the first end of the central rod pressing against one end of the hollow shaft, and a tapered plug fitted onto the second end of the central rod, pressing against the other end of the hollow shaft. When clamping the machine tool, only the position of the machine tool tip needs to be adjusted so that the machine tool tip presses against the tapered holes at both ends of the central rod. After starting the machine tool, the friction and clamping force between the tapered boss, tapered plug, and the hollow shaft achieve synchronous rotation of the centering fixture and the hollow shaft. Under the action of friction and clamping force, the machine tool tip and the central rod of the centering fixture simultaneously drive the power pin on the tapered boss to rotate through the transmission rod of the machine tool tip, thereby achieving the purpose of the machine tool tip driving the hollow shaft to rotate.

[0038] Compared to traditional centering fixtures that rely on frictional transmission, the centering fixture for hollow shafts provided by this invention not only utilizes the frictional and clamping forces between the machine tool center and the central rod of the centering fixture, but also adds a mechanical transmission method by having a power pin on the centering fixture cooperate with the transmission rod of the machine tool center. This avoids the problem of slow rotation of the hollow shaft during machining and improves the finishing effect of the hollow shaft. Furthermore, when using different lathes to perform finish turning and finish grinding on the hollow shaft, the same clamping method can be used, satisfying the concentricity and quick clamping requirements of finish turning and finish grinding on different machine tools. Simultaneously, it allows for machining of the entire area in a single clamping operation, improving machining efficiency and accuracy.

[0039] The technical features mentioned above, those to be mentioned below, and those shown individually in the accompanying drawings can be combined arbitrarily, provided that the combined technical features are not contradictory. All feasible combinations of features are the technical content explicitly described herein. Any one of the multiple sub-features contained in the same statement can be applied independently, without necessarily being applied together with other sub-features. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0041] Figure 1 is a schematic diagram of the centering fixture provided in an embodiment of the present invention;

[0042] Figure 2 is an exploded view of the centering fixture provided in an embodiment of the present invention;

[0043] Figure 3 is a schematic diagram of the machine tool provided in an embodiment of the present invention;

[0044] Figure 4 is a schematic flowchart of the processing method provided in an embodiment of the present invention;

[0045] Figure 5 is a flowchart illustrating the roughing steps provided in an embodiment of the present invention;

[0046] Figure 6 is a schematic diagram of the storage and transportation tooling provided in an embodiment of the present invention;

[0047] Figure 7 is a schematic diagram of the structure of the storage and transportation tooling provided in an embodiment of the present invention;

[0048] Figure 8 is a schematic diagram of the hollow shaft provided in an embodiment of the present invention.

[0049] Among them, 100 is the centering fixture, 101 is the center rod, 102 is the conical boss, 1021 is the power pin, 1022 is the protrusion, 1023 is the extension, 1024 is the clearance space, 103 is the conical plug, 104 is the locking mechanism, 1041 is the fastener, and 105 is the center hole.

[0050] 200 is the machining tool, 201 is the chuck, 202 is the machine tool center, and 2021 is the transmission rod;

[0051] 300 is a storage and transportation tool, 301 is the tool frame, 302 is the first support part, 303 is the second support part, 304 is a V-shaped notch, 3041 is an elastic gasket, 305 is a forklift sleeve, 306 is a hook, 307 is the first crossbeam, 308 is the second crossbeam, 309 is the intermediate crossbeam, 310 is an elastic support component, 3101 is an annular groove, 311 is a support base, 3111 is a connecting pin, and 3112 is a connecting sleeve.

[0052] 400 is a hollow shaft, 401 is the small diameter end, 4011 is a keyway, 4012 is a threaded end, 402 is the large diameter end, 4021 is the frame mating end, and 403 is an annular protrusion. Detailed Implementation

[0053] The core of this invention is to provide a centering fixture for hollow shafts, so as to improve the finishing effect of hollow shafts while ensuring the concentricity of hollow shafts during the finishing process.

[0054] Another key aspect of this invention is to provide a machine tool for machining hollow shafts that is compatible with the aforementioned centering fixture.

[0055] Another core aspect of this invention is to provide a machining method for hollow shafts using the aforementioned centering fixture.

[0056] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0057] Monorail, as an urban rail transit system, is gaining increasing attention worldwide due to its unique design and efficient transportation capabilities. Monorails use a single track to support and guide train operation, saving space compared to traditional double-track railway systems. Furthermore, the use of rubber tires on concrete tracks reduces operating noise and improves passenger comfort.

[0058] The bogie is a key rail vehicle component of a monorail train, responsible for supporting the car body, ensuring driving stability, and providing guidance. As one of the core components of a monorail train, the bogie is crucial for the safe operation of the entire train. Specifically, by mounting hollow axles onto the bogies and the running wheels onto the hollow axles, the weight of the entire vehicle and passengers is transferred through the hollow axles to the running wheels, and ultimately to the track. Therefore, the hollow axle is one of the important components for transferring the weight of the entire vehicle and passengers to the track, and its machining quality directly affects the stability and safety of the monorail train. The machining and assembly precision of the hollow axle directly affects its machining quality. During the precision machining of the hollow axle, it is necessary to ensure the concentricity of the precision turning and grinding processes to guarantee the overall machining accuracy of the hollow axle.

[0059] In traditional finishing processes, centering fixtures are typically used to ensure concentricity during precision turning and grinding. The friction between the centering fixture and the hollow shaft enables synchronous rotation, while the machine tool center drives the hollow shaft through friction transmission. However, the relatively low friction between the machine tool center and the centering fixture results in low transmission efficiency, leading to sluggish rotation of the hollow shaft during machining and poor finishing results. Furthermore, the reliance on friction to achieve synchronous rotation between the centering fixture and the hollow shaft results in poor synchronicity between them.

[0060] Based on this, as shown in Figures 1 and 2, this embodiment of the invention discloses a centering fixture 100 for a hollow shaft 400, including a center rod 101. It not only utilizes the friction and clamping force between the machine tool center 202 and the center rod 101 of the centering fixture 100, but also, through the cooperation of a power pin 1021 on the centering fixture 100 and the transmission rod 2021 of the machine tool center 202, it increases the mechanical transmission method, avoiding the problem of slow rotation of the hollow shaft 400 during machining, and improving the finishing effect of the hollow shaft 400. Furthermore, when using different lathes to perform finish turning and finish grinding on the hollow shaft 400, the same clamping method can be used, satisfying the concentricity and quick clamping requirements of finish turning and finish grinding on different machine tools. At the same time, it can achieve machining of the entire area in a single clamping, improving machining efficiency and accuracy.

[0061] The centering fixture 100 for hollow shaft 400 disclosed in the embodiments of the present invention will be explained and described in detail below with reference to Figures 1 and 2.

[0062] As shown in Figures 1 and 2, the first end of the center rod 101 is provided with a tapered boss 102 that presses against one end of the hollow shaft 400. The second end of the center rod 101 is movably fitted with a tapered plug 103 that presses against the other end of the hollow shaft 400, and the tapered plug 103 rotates synchronously with the center rod 101. Through the tapered structure design at both ends of the center rod 101, it can guide the center rod 101 towards the centerline of the hollow shaft 400, thereby realizing the automatic centering of the centering fixture 100 and the hollow shaft 400. At the same time, both ends of the center rod 101 are provided with tapered holes that cooperate with the machine tool center 202, and the tapered boss 102 is provided with a power pin 1021 that cooperates with the transmission rod 2021 of the machine tool center 202.

[0063] When clamping the machine tool, simply adjust the position of the machine tool center 202 so that it abuts against the tapered holes at both ends of the center rod 101. When performing finish turning and finish grinding on different lathes, the same clamping method can be used, satisfying the concentricity requirements and quick clamping of finish turning and finish grinding on different machine tools. Furthermore, it allows for machining of the entire area in a single clamping operation, improving machining efficiency and accuracy.

[0064] When the machine tool is started, the centering fixture 100 and the hollow shaft 400 rotate synchronously due to the friction and clamping force between the tapered boss 102 and the tapered plug 103 and the hollow shaft 400. Under the action of friction and clamping force, the machine tool tip 202 and the center rod 101 of the centering fixture 100 rotate simultaneously through the transmission rod 2021 of the machine tool tip 202, thereby achieving the purpose of the machine tool tip 202 driving the hollow shaft 400 to rotate. Based on the action of friction and clamping force between the machine tool tip 202 and the center rod 101 of the centering fixture 100, the mechanical transmission method is increased by the cooperation between the power pin 1021 set on the centering fixture 100 and the transmission rod 2021 of the machine tool tip 202. This solves the problem of slow rotation of the hollow shaft 400 during the machining process and improves the finishing effect of the hollow shaft 400.

[0065] Specifically, the tapered boss 102 can be integrally set on the first end of the center rod 101, or it can be fixed to the first end of the center rod 101 by welding. The power pin 1021 can be fixed to the side wall of the tapered boss 102 by welding. Of course, the power pin 1021 and the side wall of the tapered boss 102 can also be fixed by other detachable connection methods such as threaded engagement. At the same time, the tapered hole is set at the center position of the end face of the tapered boss 102 so that the first end of the center rod 101 can cooperate with the machine tool center 202. The tapered plug 103 can be threaded into the second end of the center rod 101 to press against the other end of the hollow shaft 400. The tapered hole is located at the center of the end face of the second end of the center rod 101. Simultaneously, a central hole 105 is provided at the center of the tapered plug 103 for the second end of the center rod 101 to pass through, facilitating the engagement of the second end of the center rod 101 with the machine tool center 202. This allows the machine tool centers 202 at both ends of the center rod 101 to press against the corresponding tapered holes on the center rod 101, thereby enabling the machining tool 200 to clamp the hollow shaft 400. Alternatively, the tapered plug 103 can be clearance-fitted with the second end of the center rod 101. When the tapered plug 103 presses against the hollow shaft 400, it can be secured with fasteners 1041.

[0066] As shown in Figures 1 and 2, in one specific embodiment, the center rod 101 has a stepped shaft structure, and the outer diameter of the first end of the center rod 101 is larger than the outer diameter of the second end of the center rod 101. The conical plug 103 is slidably engaged with the second end of the center rod 101, and a locking mechanism 104 is provided at the second end of the center rod 101 to prevent the conical plug 103 from sliding. Specifically, the locking mechanism 104 includes a threaded portion provided at the second end of the center rod 101 and a fastener 1041 that engages with the threaded portion. The fastener 1041 abuts against the conical plug 103 to prevent the conical plug 103 from sliding, thereby clamping the two ends of the hollow shaft 400 between the conical plug 103 and the conical boss 102. At the same time, in order to facilitate the engagement of the second end of the center rod 101 with the machine tool center 202, a central hole 105 is provided on both the fastener 1041 and the conical plug 103 for the second end of the center rod 101 to pass through. In this embodiment, the fastener 1041 can be, but is not limited to, a hexagonal flange nut. Of course, the locking mechanism 104 can also adopt an axial locking structure such as a snap ring, which will not be described in detail here.

[0067] Furthermore, as shown in Figures 1 and 2, in order to ensure synchronous rotation between the hollow shaft 400 and the centering fixture 100 and improve the synchronicity between them, a protrusion 1022 that mates with the hollow shaft 400 is provided on the side wall of the tapered boss 102 at the first end of the center rod 101. For ease of understanding, as shown in Figure 8, the end with the smaller outer diameter of the hollow shaft 400 is defined as the small diameter end 401, and the end with the larger outer diameter is defined as the large diameter end 402. The tapered boss 102 is used to press against the small diameter end 401 of the hollow shaft 400, and the tapered plug 103 is used to press against the large diameter end 402 of the hollow shaft 400. A keyway 4011 is provided at the small diameter end 401 of the hollow shaft 400. When the tapered boss 102 presses against the small-diameter end 401 of the hollow shaft 400, the protrusion 1022 on the side wall of the tapered boss 102 engages with the keyway 4011 of the hollow shaft 400, realizing synchronous rotation between the hollow shaft 400 and the centering fixture 100. Based on the friction and clamping force between the tapered boss 102 and the tapered plug 103 and the hollow shaft 400, a mechanical transmission method is added, which improves the synchronicity between the hollow shaft 400 and the centering fixture 100, avoids the problem of slow rotation of the hollow shaft 400 during the machining process, and further improves the finishing effect of the hollow shaft 400.

[0068] As shown in Figure 1, in one specific embodiment, the protrusion 1022 is fixed to the side wall of the conical boss 102 by welding, and the protrusion 1022 has an extension 1023 extending out of the side wall of the conical boss 102 along the axial direction of the central rod 101. A clearance space 1024 for inserting the hollow shaft 400 is formed between the extension 1023 and the central rod 101. When the conical boss 102 presses against the small-diameter end 401 of the hollow shaft 400, the side wall of the small-diameter end 401 of the hollow shaft 400 extends into the clearance space 1024, and at the same time, the extension 1023 of the protrusion 1022 is inserted into the keyway 4011 of the small-diameter end 401 of the hollow shaft 400. When the transmission rod 2021 of the machine tool center 202 drives the power pin 1021 on the tapered boss 102 to rotate, the protrusion 1022 on the tapered boss 102 engages with the keyway 4011 of the hollow shaft 400, thereby driving the hollow shaft 400 to rotate synchronously.

[0069] As shown in Figure 3, this embodiment of the invention also discloses a machine tool 200 for processing hollow shafts 400, including a chuck 201 and a machine tool center 202 disposed on the chuck 201. The machine tool center 202 is provided with a transmission rod 2021 that cooperates with a centering fixture. This centering fixture is the centering fixture 100 for hollow shafts 400 disclosed in the above embodiment, and therefore possesses all the technical effects of the aforementioned centering fixture 100, which will not be elaborated upon further here.

[0070] For ease of understanding, the two machine tool centers 202 on the machine tool 200 are defined as a telescopic center and a transmission center, respectively. The telescopic center is used to press against the second end of the center rod 101 of the centering fixture 100, and the transmission center is mounted on the chuck 201 to press against the first end of the center rod 101 of the centering fixture 100. Meanwhile, a transmission rod 2021 is mounted on the side wall of the transmission center so that when the transmission center rotates, the transmission rod 2021 engages with the power pin 1021 at the first end of the center rod 101, thereby driving the centering fixture 100 to rotate. Specifically, the transmission rod 2021 adopts an L-shaped structure, and one end of the transmission rod 2021 is fixed to the side wall of the machine tool tip 202 by welding. Specifically, it can be welded to the side wall of the transmission tip. At the same time, the other end of the transmission rod 2021 abuts against the power pin 1021 of the centering fixture 100, so that the centering fixture 100 can be rotated through the transmission rod 2021 on the transmission tip. This solves the problem of slow rotation of the hollow shaft 400 during the machining process and improves the finishing effect of the hollow shaft 400.

[0071] As shown in Figure 4, this embodiment of the invention also discloses a machining method for a hollow shaft 400, including rough machining in S100 and finish machining in S101.

[0072] The processing method for hollow shaft 400 disclosed in the embodiments of the present invention will be explained and described in detail below with reference to Figures 4 to 8.

[0073] S100, rough machining;

[0074] A rough hollow shaft is formed by machining a blank round steel tube. As shown in Figure 8, the rough hollow shaft includes a threaded end 4012 and a frame mating end 4021. The threaded end 4012 has a keyway 4011, and an annular protrusion 403 is provided between the threaded end 4012 and the frame mating end 4021. It should be noted that the frame mating end 4021 is the end that mates with the bogie, and the threaded end 4012 is the end that mates with the traveling wheel.

[0075] Specifically, as shown in Figure 5, the rough machining process of S100 includes machining the frame mating end of S100a, machining the threaded end of S100b, and machining the keyway of S100c. These will be explained and described in detail below.

[0076] S100a, machining frame mating end;

[0077] The first end of the blank round steel pipe is machined using a conventional lathe and a three-jaw self-centering chuck to form the frame mating end 4021, with a certain amount of finishing allowance reserved.

[0078] S100b, for machining threaded ends;

[0079] The blank round steel tube is flipped over and clamped using a conventional lathe with a three-jaw self-centering chuck and an S100a machining arm to machine the area at the mating end of the frame. A threaded end 4012 is formed at the second end of the blank round steel tube. By adjusting the machining sequence of the threaded end 4012 and the mating end 4021, damage to the end threads during subsequent machining can be effectively avoided, thus preventing impact on later installation and use.

[0080] S100c, machined keyway;

[0081] The threaded end 4012 of the blank round steel pipe is machined using a CNC milling machine to form a keyway 4011.

[0082] After the S100 rough machining is completed, a rough hollow shaft is formed. At this time, the key parts of the hollow shaft 400 need to be finished by S101 to ensure the assembly accuracy of the hollow shaft 400.

[0083] S101, precision machining;

[0084] In the finishing process, a centering fixture is used to form the hollow shaft finished product. This centering fixture is the centering fixture 100 for the hollow shaft 400 disclosed in the above embodiment, and therefore possesses all the technical effects of the aforementioned centering fixture 100, which will not be repeated here. To meet the high dimensional accuracy requirements of the hollow shaft 400, in this embodiment, the finishing process includes precision turning and precision grinding. The specific steps include:

[0085] Step A: After removing the fastener 1041 and conical plug 103 from the centering fixture 100, insert the hollow shaft 400 into the center rod 101. The keyway 4011 on the hollow shaft 400 mates with the extension 1023 of the protrusion 1022. After inserting the conical plug 103, tighten the fastener 1041 to complete the installation.

[0086] Step B involves clamping the coarse hollow shaft by engaging the transmission center on the chuck 201 of the machine tool 200 with the telescopic center on the tailstock of the machine tool 200, and then performing finish machining on the coarse hollow shaft.

[0087] Step C: Using the same clamping method, the rough hollow shaft is precision ground to ensure that the finished hollow shaft meets the design requirements.

[0088] It should be noted that different machine tools are required for the aforementioned precision turning and precision grinding processes. Specifically, a CNC lathe can be used for precision turning of the rough hollow shaft, while a grinding machine can be used for precision grinding. By employing the centering fixture 100 disclosed in this embodiment of the invention, the same clamping method can be used when performing precision turning and precision grinding of the hollow shaft 400 on different machine tools. This satisfies the concentricity and quick clamping requirements of precision turning and precision grinding on different machine tools, and allows for machining of the entire area in a single clamping operation, thereby improving machining efficiency and accuracy.

[0089] Furthermore, a step transport of the rough hollow shaft is included between the S100 rough machining and S101 finish machining. To improve space utilization and transport efficiency, as shown in Figures 6 and 7, the rough hollow shaft is transported to the finish machining location via a storage and transport fixture 300.

[0090] Further, as shown in Figure 6, the storage and transportation fixture 300 includes at least one fixture frame 301, and the fixture frame 301 is respectively provided with a first support portion 302 for supporting the threaded end 4012 of the hollow shaft and a second support portion 303 for supporting the frame mating end 4021 of the hollow shaft. Meanwhile, both the first support portion 302 and the second support portion 303 are respectively provided with V-shaped notches 304 that mate with the end of the hollow shaft, so that the threaded end 4012 and the frame mating end 4021 of the hollow shaft are respectively supported within the V-shaped notches 304 of the first support portion 302 and the second support portion 303, thereby protecting the threaded end 4012 and the frame mating end 4021 of the hollow shaft through the sidewalls of the V-shaped notches 304.

[0091] Furthermore, to reduce the impact of vibrations generated during transportation on the end of the hollow shaft, an elastic gasket 3041 is provided on the inner wall of the V-shaped notch 304 to better protect the end of the hollow shaft and prevent damage during storage or transportation, which could affect subsequent installation and use. In this embodiment, the elastic gasket 3041 can be, but is not limited to, a nylon gasket. Of course, the first support portion 302 and the second support portion 303 can also be directly made of elastic material.

[0092] As shown in Figure 6, in one specific embodiment, the tooling frame 301 includes a first crossbeam 307 and a second crossbeam 308 arranged in parallel, and the two ends of the first crossbeam 307 and the second crossbeam 308 are connected by longitudinal beams to form a frame system. Meanwhile, there are multiple first support parts 302, and each first support part 302 is spaced apart on the first crossbeam 307. Second support parts 303 are arranged on the second crossbeam 308 in a one-to-one correspondence with the first support parts 302, so that multiple thick hollow shafts can be placed on one tooling frame 301. When it is necessary to transport thick hollow shafts, multiple thick hollow shafts can be transported simultaneously through the storage and transportation tooling 300, improving transportation efficiency.

[0093] Further, as shown in Figures 6 and 7, to ensure the stability of the transport of the hollow shaft, an intermediate crossbeam 309 is arranged parallel to the first crossbeam 307 and the second crossbeam 308. An elastic support member 310, corresponding one-to-one with the first support portion 302, is provided on the intermediate crossbeam 309. Simultaneously, an annular groove 3101, adapted to the annular protrusion 403 of the hollow shaft, is formed on the elastic support member 310. When both ends of the hollow shaft are supported within the V-shaped notches 304 of the first support portion 302 and the second support portion 303 respectively, the annular protrusion 403 of the hollow shaft inserts into the annular groove 3101 of the elastic support member 310, thereby limiting the axial movement of the hollow shaft and ensuring the stability of its transport. In this embodiment, the elastic support member 310 may be made of, but is not limited to, nylon material to reduce the impact of vibration on the hollow shaft.

[0094] Furthermore, in order to improve space utilization, as shown in Figures 6 and 7, the tooling frame 301 also includes a support base 311 for supporting the storage and transportation tooling 300, and the support base 311 has two opposite ends. For ease of understanding, the two ends of the support base 311 are defined as the first end and the second end, respectively. A connecting pin 3111 is provided at the first end of the support base 311, i.e., the top end of the support base 311, and a connecting sleeve 3112 that cooperates with the connecting pin 3111 of the adjacent tooling frame 301 is provided at the second end of the support base 311, i.e., the bottom end of the support base 311. As shown in Figure 7, when there are two or more tooling frames 301, they can be stacked. The connecting pin 3111 at the first end of the support base 311 of the lower tooling frame 301 is inserted into the connecting sleeve 3112 at the second end of the support base 311 of the upper tooling frame 301 to connect and fix adjacent tooling frames 301. This vertical stacking of tooling frames 301 reduces the space occupied by the storage and transportation tooling 300, improving space utilization.

[0095] Furthermore, as shown in Figures 6 and 7, in order to facilitate the handling and transportation of the storage and transportation tooling 300, a forklift sleeve 305 is provided on the tooling frame 301. Specifically, the forklift sleeve 305 can be set at the bottom of the first crossbeam 307 and the second crossbeam 308, and two forklift sleeves 305 are respectively set on the first crossbeam 307 and the second crossbeam 308. At the same time, the forklift sleeves 305 of the first crossbeam 307 and the second crossbeam 308 are set one-to-one to ensure that the forklift can be inserted into the forklift sleeves 305 of the first crossbeam 307 and the second crossbeam 308, thereby transporting the storage and transportation tooling 300 smoothly. Of course, hooks 306 can also be installed on the tooling frame 301 to lift and move the storage and transportation tooling 300 using lifting equipment. Specifically, hooks 306 can be installed on one side of the support base 311. To ensure the stability of the lifting, four hooks 306 are used and symmetrically distributed on the support bases 311 at the four corners of the tooling frame 301 to form a four-point force system, thereby ensuring that the storage and transportation tooling 300 is lifted smoothly by the lifting equipment. It should be noted that hooks 306 and forklift sleeves 305 can also be installed on the tooling frame 301 at the same time, and can be flexibly selected according to the actual situation when moving the storage and transportation tooling 300.

[0096] It should be noted that, unless otherwise specified, the storage and transportation fixtures 300 in the above embodiments are all made of metal and are connected and fixed by welding. For non-metallic parts, they can be fixed by adhesive or bolt connection.

[0097] The terms "first" and "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units may include steps or units not listed, but rather steps or units not listed.

[0098] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A centering tool for a hollow shaft, characterized in that, The center rod (101) is provided with a tapered hole at both ends for cooperating with a machine center (202), and a first end of the center rod (101) is provided with a tapered boss (102) for tightly pressing one end of the hollow shaft (400), and a second end of the center rod (101) is movably sleeved with a tapered plug (103) for tightly pressing the other end of the hollow shaft (400), the tapered plug (103) rotates synchronously with the center rod (101), and the tapered boss (102) is provided with a power pin (1021) for cooperating with a transmission rod (2021) of the machine center (202). The hollow shaft (400) has a small-diameter end (401) and a large-diameter end (402) arranged oppositely, the tapered boss (102) is used for tightly pressing the small-diameter end (401) of the hollow shaft (400), the tapered plug (103) is used for tightly pressing the large-diameter end (402) of the hollow shaft (400), and the small-diameter end (401) of the hollow shaft (400) is provided with a key groove (4011), and the side wall of the tapered boss (102) is provided with a protrusion (1022) for cooperating with the key groove (4011).

2. The centering fixture according to claim 1, characterized in that, The protrusion (1022) is provided with an extension (1023) protruding from the side wall of the tapered boss (102) in the axial direction of the center rod (101), and the extension (1023) and the center rod (101) form an avoidance space (1024) for inserting the hollow shaft (400).

3. The centering tool of claim 2, wherein, The center rod (101) is in a stepped shaft structure, the outer diameter of the first end of the center rod (101) is greater than the outer diameter of the second end of the center rod (101), the tapered plug (103) is in sliding cooperation with the second end of the center rod (101), and the second end of the center rod (101) is provided with a locking mechanism (104) for locking the sliding of the tapered plug (103).

4. The centering tool of claim 1, wherein, The locking mechanism (104) includes a threaded portion provided on the second end of the center rod (101) and a fastener (1041) cooperating with the threaded portion, and the fastener (1041) is used for abutting against the tapered plug (103).

5. The centering tool of claim 4, wherein, The fastener (1041) and the tapered plug (103) are respectively provided with a center hole (105) for the second end of the center rod (101) to pass through.

6. The centering tool of claim 5, wherein, The center rod (101) is provided with a tapered hole at both ends for cooperating with a machine center (202), and a first end of the center rod (101) is provided with a tapered boss (102) for tightly pressing one end of the hollow shaft (400), and a second end of the center rod (101) is movably sleeved with a tapered plug (103) for tightly pressing the other end of the hollow shaft (400), the tapered plug (103) rotates synchronously with the center rod (101), and the tapered boss (102) is provided with a power pin (1021) for cooperating with a transmission rod (2021) of the machine center (202).

7. A machine tool for machining a hollow shaft, characterized in that The transmission rod (2021) is in an L-shaped structure, one end of the transmission rod (2021) is fixed to the side wall of the machine center (202), and the other end of the transmission rod (2021) is used for abutting against the power pin (1021) of the centering tool (100).

8. The machine tool according to claim 7, characterized in that The center rod (101) is provided with a tapered hole at both ends for cooperating with a machine center (202), and a first end of the center rod (101) is provided with a tapered boss (102) for tightly pressing one end of the hollow shaft (400), and a second end of the center rod (101) is movably sleeved with a tapered plug (103) for tightly pressing the other end of the hollow shaft (400), the tapered plug (103) rotates synchronously with the center rod (101), and the tapered boss (102) is provided with a power pin (1021) for cooperating with a transmission rod (2021) of the machine center (202).

9. A method for machining a hollow shaft, characterized in that The transmission rod (2021) is in an L-shaped structure, one end of the transmission rod (2021) is fixed to the side wall of the machine center (202), and the other end of the transmission rod (2021) is used for abutting against the power pin (1021) of the centering tool (100). The center rod (101) is provided with a tapered hole at both ends for cooperating with a machine center (202), and a first end of the center rod (101) is provided with a tapered boss (102) for tightly pressing one end of the hollow shaft (400), and a second end of the center rod (101) is movably sleeved with a tapered plug (103) for tightly pressing the other end of the hollow shaft (400), the tapered plug (103) rotates synchronously with the center rod (101), and the tapered boss (102) is provided with a power pin (1021) for cooperating with a transmission rod (2021) of the machine center (202). The transmission rod (2021) is in an L-shaped structure, one end of the transmission rod (2021) is fixed to the side wall of the machine center (202), and the other end of the transmission rod (2021) is used for abutting against the power pin (1021) of the centering tool (100). Coarsely machining a blank round steel pipe to form a rough hollow shaft, the rough hollow shaft comprising a threaded end (4012) and a frame matching end (4021), the threaded end (4012) being provided with a key groove (4011), and the threaded end (4012) and the frame matching end (4021) being provided with an annular protrusion (403) therebetween; Finely machining the rough hollow shaft to form a finished hollow shaft, the fine machining comprising fine turning and fine grinding.

10. The method of claim 9, wherein, The step of coarsely machining specifically comprises: Machining the frame matching end, machining the first end of the blank round steel pipe to form the frame matching end (4021); Machining the threaded end, turning over the blank round steel pipe and machining the second end of the blank round steel pipe to form the threaded end (4012); Machining the key groove, machining the threaded end (4012) of the blank round steel pipe to form the key groove (4011).

11. The method of claim 9, wherein, The step of coarsely machining and the step of finely machining further comprise a step of: Transporting the rough hollow shaft, transporting the rough hollow shaft to the position for fine machining by a storage and transportation tool (300). The storage and transportation tool (300) comprises at least one tool rack body (301), the tool rack body (301) being respectively provided with a first supporting part (302) for supporting the threaded end (4012) of the rough hollow shaft and a second supporting part (303) for supporting the frame matching end (4021) of the rough hollow shaft, and the first supporting part (302) and the second supporting part (303) are respectively provided with a V-shaped notch (304) matched with the end of the rough hollow shaft.

12. The method of claim 11, wherein, The tool rack body (301) is provided with a forklift sleeve (305); and / or, 13. The method of claim 12, wherein, The tool rack body (301) is provided with a lifting hook (306); and / or, The inner wall of the V-shaped notch (304) is provided with an elastic gasket (3041). The tool rack body (301) comprises a first cross beam (307) and a second cross beam (308) arranged in parallel, the first supporting part (302) is a plurality of, and each first supporting part (302) is distributed on the first cross beam (307), and the second supporting part (303) is arranged on the second cross beam (308) corresponding to the first supporting part (302).

14. The method of claim 12, wherein, The first cross beam (307) and the second cross beam (308) are provided with an intermediate cross beam (309) arranged in parallel therebetween, the intermediate cross beam (309) is provided with an elastic supporting part (310) corresponding to the first supporting part (302), and the elastic supporting part (310) is provided with an annular groove (3101) matched with the annular protrusion (403) of the rough hollow shaft.

15. The method of claim 14, wherein, ​ 16. The method of claim 14, wherein The tooling frame (301) also includes a support base (311) for supporting the storage and transportation tooling (300). The support base (311) has a first end and a second end that are disposed opposite to each other. The first end of the support base (311) is provided with a connecting pin (3111), and the second end of the support base (311) is provided with a connecting sleeve (3112) for cooperating with the connecting pin (3111) of the adjacent tooling frame (301).

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