A polyurethane wheelset

Abstract

The utility model discloses a kind of polyurethane wheel sets, it is related to polyurethane wheel set technical field, including mandrel, connecting piece and polyurethane wheel piece, several polyurethane wheel pieces are installed on the outer wall of the mandrel, and are connected with the mandrel by the connecting piece, the outer wall of several polyurethane wheel pieces is all arc-shaped setting.Polyurethane wheel piece has three layers, including wheel core, modulus gradient transition layer and polyurethane layer, this setting mode changes stress transmission path, when wheel piece bears load, the pressure suffered by polyurethane layer is transmitted to wheel core after buffering by modulus gradient transition layer, so that the stress between polyurethane layer and modulus gradient transition layer is significantly smaller than the stress between polyurethane layer and metal wheel core of conventional structure wheel piece, and this stress optimization greatly prolongs the fatigue life of wheel piece, and in the process of shield machine tunneling, polyurethane layer shedding failure phenomenon is greatly reduced.

Description

Technical Field

[0001] This utility model relates to the field of polyurethane wheel assembly technology, and in particular to a polyurethane wheel assembly. Background Technology

[0002] Polyurethane wheel assemblies on tunnel boring machines (TBMs) are typically assembled by press-fitting wheel plates with a cylindrical steel mandrel using an interference fit. The wheel plates are made by casting polyurethane material onto the surface of a steel rim. During use, polyurethane wheel assemblies frequently experience failure due to the polyurethane layer peeling off from the steel rim surface. When this happens, the entire wheel assembly needs to be replaced, leading to project downtime. After tunneling a certain distance, the polyurethane layer on the wheel plates wears down, requiring replacement before resuming work. Because the wheel plates are press-fitted onto the mandrel using an interference fit, they cannot be disassembled. The steel rim is usually removed from the mandrel surface by machining. After press-fitting, the mandrel surface is prone to severe scratches, rendering it unusable and resulting in high maintenance costs. Utility Model Content

[0003] The purpose of this invention is to provide a polyurethane wheel assembly to solve the above-mentioned technical problems.

[0004] The technical solution adopted in this utility model is as follows: A polyurethane wheel assembly includes a spindle, a connector, and polyurethane wheel pieces. A plurality of the polyurethane wheel pieces are mounted on the outer wall of the spindle and connected to the spindle via the connector. The outer walls of the plurality of polyurethane wheel pieces are all arc-shaped.

[0005] Preferably, four polyurethane wheels are provided, with two polyurethane wheels on both sides arranged symmetrically and two polyurethane wheels in the middle arranged symmetrically.

[0006] As a further preferred embodiment, each of the polyurethane wheel pieces includes a wheel core, a modulus gradient transition layer, and a polyurethane layer. The wheel core is connected to the spindle, the modulus gradient transition layer is disposed on the outer wall of the wheel core, and the polyurethane layer is disposed on the outer wall of the modulus gradient transition layer.

[0007] As a further preferred embodiment, the outer wall of the wheel core is provided with a plurality of protrusions, and a groove is formed between two adjacent protrusions.

[0008] As a further preferred embodiment, a first flange is provided on the inner wall of the wheel core, and a second flange is provided on the outer wall of the spindle, with the first flange and the second flange engaging.

[0009] As a further preferred embodiment, the connector includes a stud and a nut, the stud connecting the first flange and the second flange, and the nut being disposed on the stud.

[0010] As a further preferred embodiment, the connection between the stud and the nut is pre-coated with thread-locking agent.

[0011] A method for manufacturing a polyurethane wheel set, comprising the aforementioned polyurethane wheel set, wherein the manufacturing method includes: Step 1: Gear core machining. Gutters and bosses are machined on the outer peripheral wall of the gear core. First, four grooves are machined on the outer peripheral wall of the gear core, namely two first grooves and two second grooves. The two first grooves are located between the two second grooves. Then, a third groove is milled between the two first grooves. Then, a fourth groove is milled between the first groove and the second groove. At this time, the third groove and the two fourth grooves are distributed in a triangle to form a boss. Then, following this groove milling method, several third grooves are milled between the two first grooves, and several fourth grooves are milled between the first groove and the second groove, thus forming several staggered bosses. Step 2: Use MC nylon to make a modulus gradient transition layer, and combine the modulus gradient transition layer with the wheel core to form a composite wheel core; Step 3: Surface pretreatment of composite wheel core; Step 4: Pour the polyurethane layer.

[0012] As a further preferred option, in step 2, the wheel core is first preheated to 120±10℃ and placed into the mold. Under inert gas protection, the caprolactam monomer is heated and melted, 0.2% of the catalyst NaOH is added, and the mixture is stirred and mixed evenly. The temperature is raised and vacuum is applied, and the mixture is kept at 110℃ for 15~20 minutes to reduce the moisture content to below 300ppm. Then the vacuum is stopped, 0.3% of the co-catalyst TDI is added, and the mixture is stirred and mixed evenly before being quickly poured into the mold. The mold temperature is maintained at 160℃~170℃ in an oven, and the polymerization reaction is carried out for 15~20 minutes. The polymerization reaction forms an MC nylon gradient transition layer.

[0013] As a further preferred option, step 3 includes the following steps: Step 301, Sandblasting: Use 60-mesh brown corundum and a sandblasting pressure of 0.6MPa to sandblast the outer surface of the composite wheel core to achieve a surface roughness Ra of 6.3~12.5μm. After sandblasting, use compressed air to blow away the dust on the sandblasted surface. Step 302, Apply primer: Apply polyurethane-specific primer, dry film thickness 20~30μm, pre-cur at 110℃ for 120 minutes.

[0014] The above technical solution has the following advantages or beneficial effects: (1) In this utility model, the polyurethane wheel has three layers, including a wheel core, a modulus gradient transition layer and a polyurethane layer. This arrangement changes the stress transmission path. When the wheel bears a load, the pressure on the polyurethane layer is buffered by the modulus gradient transition layer and then transmitted to the wheel core. This makes the stress between the polyurethane layer and the modulus gradient transition layer significantly less than the stress between the polyurethane layer and the metal wheel core of the conventional structure wheel. This stress optimization greatly extends the fatigue life of the wheel and significantly reduces the phenomenon of polyurethane layer falling off during the tunneling process of the shield machine.

[0015] (2) In this utility model, the wheel and the spindle are connected by nuts and double-ended studs, which makes it extremely convenient to replace the wheel after the tunnel boring machine has tunneled a certain distance. Unlike the traditional method, there is no need to use complex disassembly methods such as turning, which damage the spindle. This avoids the problem that the spindle cannot be reused due to surface scratches caused by disassembly. This not only saves the cost of replacing the spindle, but also reduces maintenance time and reduces the indirect costs caused by project shutdown.

[0016] (3) In this utility model, compared with the conventional solid spindle polyurethane wheel assembly structure, the structural weight of this utility model is reduced by about 44%. The lighter wheel assembly weight not only reduces the overall load of the tunnel boring machine, which is conducive to the efficient operation of the tunnel boring machine, but also makes maintenance and replacement operations easier. When maintenance personnel replace the wheel pieces, the operation difficulty and labor intensity are reduced, further improving maintenance efficiency and reducing the safety risks that may be caused by difficult maintenance operations.

[0017] (4) In this utility model, the extended service life of the wheel pieces, the reduced maintenance costs, and the ease of repair and replacement operations significantly improve the construction efficiency of the tunnel boring machine. It reduces downtime caused by wheel piece problems, enabling the tunnel boring machine to work more continuously and stably, accelerating the tunnel excavation speed, and providing a strong guarantee for the smooth progress of the project. Attached Figure Description

[0018] Figure 1 This is a cross-sectional schematic diagram of the polyurethane wheel assembly in this utility model; Figure 2 This is a schematic cross-sectional view of the polyurethane wheel in this utility model; Figure 3 This is a schematic diagram of the mandrel structure in this utility model; Figure 4 This is a diagram showing the usage state of the polyurethane wheel assembly in this utility model; Figure 5 This is a schematic diagram showing the distribution of the bosses on the outer wall of the wheel core in this invention.

[0019] In the diagram: 1. Mandrel; 2. Connector; 201. Double-ended stud; 202. Nut; 3. Polyurethane wheel; 301. Wheel core; 302. Modulus gradient transition layer; 303. Polyurethane layer; 304. Boss; 305. First flange; 306. First groove; 307. Second groove; 308. Third groove; 309. Fourth groove; 4. Second flange; 5. Tunnel concrete segment. Detailed Implementation

[0020] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0021] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0023] Figure 1 This is a cross-sectional schematic diagram of the polyurethane wheel assembly in this utility model; Figure 2 This is a schematic cross-sectional view of the polyurethane wheel in this utility model; Figure 3 This is a schematic diagram of the mandrel structure in this utility model; Figure 4 This is a diagram showing the usage state of the polyurethane wheel assembly in this utility model; Figure 5 This is a schematic diagram showing the distribution of the bosses on the outer wall of the wheel core in this invention. Please refer to [link / reference]. Figures 1 to 5The diagram illustrates a preferred embodiment of a polyurethane wheel assembly, comprising a spindle 1, a connector 2, and polyurethane wheel pieces 3. A plurality of polyurethane wheel pieces 3 are mounted on the outer wall of the spindle 1 and connected to the spindle 1 via the connector 2. The outer walls of all the polyurethane wheel pieces 3 are arc-shaped. In this embodiment, the connector 2, unlike the traditional interference fit press-fit method, facilitates easy disassembly and replacement between the wheel pieces and the spindle 1. When the tunnel boring machine needs to replace the wheel pieces after excavating a certain distance, it eliminates the need for complex and damaging methods such as turning, as is common in traditional methods, greatly simplifying the maintenance process, reducing damage to the spindle 1, and thus saving significant maintenance costs. In this embodiment, the polyurethane wheel pieces 3 are sequentially distributed along the axial direction of the spindle 1, and the arc shape of the outer wall of the polyurethane wheel pieces 3 matches the arc shape of the tunnel concrete segment 5.

[0024] Furthermore, as a preferred embodiment, four polyurethane wheel pieces 3 are provided, with two polyurethane wheel pieces 3 symmetrically arranged on both sides and two polyurethane wheel pieces 3 symmetrically arranged in the middle. This layout helps to distribute the force and further improve the stability of the polyurethane wheel assembly.

[0025] Furthermore, as a preferred embodiment, each polyurethane wheel 3 includes a wheel core 301, a modulus gradient transition layer 302, and a polyurethane layer 303. The wheel core 301 is connected to the spindle 1, the modulus gradient transition layer 302 is disposed on the outer wall of the wheel core 301, and the polyurethane layer 303 is disposed on the outer wall of the modulus gradient transition layer 302. The arrangement of the wheel core 301, modulus gradient transition layer 302, and polyurethane layer 303 forms a three-layer structure, changing the force transmission mode of the wheel slab. When the wheel slab is under load, the pressure borne by the polyurethane layer 303 is first transmitted to the modulus gradient transition layer 302, and then from the modulus gradient transition layer 302 to the metal wheel core 301. Compared to conventional wheel slab structures, the stress between the polyurethane layer 303 and the modulus gradient transition layer 302 is significantly less than the stress between the polyurethane layer 303 and the wheel core 301, thereby significantly extending the fatigue life of the wheel slab, greatly reducing the phenomenon of polyurethane layer 303 detachment and failure during tunneling, and improving the service life and stability of the wheel assembly.

[0026] Furthermore, as a preferred embodiment, the outer wall of the wheel core 301 is provided with a plurality of protrusions 304, and a groove is formed between two adjacent protrusions 304. The protrusions 304 can hold the modulus gradient transition layer 302 in place, preventing relative displacement between the modulus gradient transition layer 302 and the wheel core 301 when the polyurethane wheel is under load. See also Figure 5As shown, firstly, four grooves are machined on the outer peripheral wall of the wheel core 301: two first grooves 306 and two second grooves 307. The two first grooves 306 are located between the two second grooves 307. Then, a third groove 308 is milled between the two first grooves 306. Next, a fourth groove 309 is milled between the first grooves 306 and the second grooves 307. At this point, the third groove 308 and the two fourth grooves 309 are arranged in a triangle to form a boss. Then, following this milling method, several third grooves 308 are milled between the two first grooves 306, and several fourth grooves 309 are milled between the first grooves 306 and the second grooves 307. This forms three rings of bosses 304, and adjacent rings of bosses 304 are staggered. For details, please refer to [reference needed]. Figure 5 As shown. The boss 304 formed in this way can effectively prevent the modulus gradient transition layer 302 from undergoing relative displacement along the circumferential direction and the axial direction.

[0027] Of course, the number and number of bosses 304 on the wheel hub 301 can be set as needed, and are not limited to... Figure 5 As shown. In this embodiment, by setting the first groove 306, the second groove 307, the third groove 308 and the fourth groove 309, the modulus gradient transition layer 302 is prevented from rotating around the axis of the wheel core 301 under the load state of the wheel piece.

[0028] Furthermore, as a preferred embodiment, a first flange 305 is provided on the inner wall of the wheel core 301, and a second flange 4 is provided on the outer wall of the spindle 1. The first flange 305 and the second flange 4 are snapped together. The connecting component 2 includes a double-ended stud 201 and a nut 202. The double-ended stud 201 connects the first flange 305 and the second flange 4, and the nut 202 is provided on the double-ended stud 201. Thread locking agent is pre-applied to the connection between the double-ended stud 201 and the nut 202. The first flange 305 and the second flange 4 are first positioned by snapping together, and then locked and fixed by the double-ended stud 201 and the nut 202. The use of thread locking agent ensures the reliability of the connection between the wheel core and the spindle 1, preventing loosening during the operation of the tunnel boring machine.

[0029] The above description is only a preferred embodiment of the present utility model and does not limit the scope of protection and implementation of the present utility model. The present utility model also has the following manufacturing method based on the above embodiments.

[0030] A method for manufacturing a polyurethane wheel assembly, the method comprising: Step 1: Machining the wheel core 301. Grooves and bosses 304 are machined on the outer peripheral wall of the wheel core 301 to provide better conditions for subsequent bonding with the modulus gradient transition layer 302. During the machining process, the size and shape of the grooves and bosses 304 are precisely controlled to ensure a tight bond between the wheel core 301 and the modulus gradient transition layer 302.

[0031] Step 2: Use MC nylon to make a modulus gradient transition layer 302, and combine the modulus gradient transition layer 302 with the wheel core 301 to form a composite wheel core 301; Step 3: Surface pretreatment of composite wheel core 301; Step 4: Pour the polyurethane layer 303.

[0032] Furthermore, as a preferred embodiment, in step 2, the wheel core 301 is first preheated to 120±10℃ and placed into the mold. Under inert gas protection, the caprolactam monomer is heated and melted, 0.2% of the catalyst NaOH is added, and the mixture is stirred and mixed evenly. The temperature is raised and a vacuum is drawn, and the mixture is kept at 110℃ for 15~20 minutes to reduce the moisture content to below 300ppm. Then the vacuum is stopped, 0.3% of the co-catalyst TDI (toluene diisocyanate) is added, and the mixture is stirred and mixed evenly before being quickly poured into the mold. The mold temperature is kept at 160℃~170℃ in an oven, and a polymerization reaction is carried out for 15~20 minutes. The polymerization reaction forms an MC nylon gradient transition layer. This manufacturing method can precisely control the performance and quality of the modulus gradient transition layer 302, allowing it to better play its role in stress transition.

[0033] Furthermore, as a preferred embodiment, step 3 includes the following steps: Step 301, Sandblasting: Use 60-mesh brown corundum and a sandblasting pressure of 0.6MPa to sandblast the outer surface of the composite wheel core 301 to achieve a surface roughness Ra of 6.3~12.5μm. After sandblasting, use compressed air to blow away the dust on the sandblasted surface to increase the surface roughness and improve the adhesion of the base adhesive.

[0034] Step 302: Apply primer: Apply a polyurethane-specific primer with a dry film thickness of 20~30μm, pre-cur at 110℃ for 120 minutes to further enhance the adhesion between the wheel core 301 and the polyurethane layer 303.

[0035] In this embodiment, the polyurethane wheel assembly includes four polyurethane wheel pieces 3, with the two outer polyurethane wheel pieces 3 being identical and symmetrically installed, and the two inner polyurethane wheel pieces 3 being identical and symmetrically installed. The outer contour of the polyurethane layer 303 is designed to be arc-shaped, matching the curvature of the tunnel concrete segment 5. The mandrel 1 is provided with the same number of second flanges 4 as the polyurethane wheel pieces 3. The first flanges 305 of the polyurethane wheel pieces 3 are installed on the second flanges 4 of the mandrel 1. One end of the double-ended stud 201 is coated with thread-locking agent and inserted into the threaded hole of the second flange 4. The first flange 305 is then locked with a nut 202. The diameter d2 of the central hole of the first flange 305 of the two middle polyurethane wheel pieces 3 is larger than the diameter d1 of the second flanges 4 at both ends of the mandrel 1 so that the two middle polyurethane wheel pieces 3 can be smoothly installed.

[0036] When the wheel assembly is under load, each polyurethane wheel slab 3 experiences radial pressure at its contact point with the tunnel concrete segment 5. The polyurethane layer 303 transfers the pressure to the modulus gradient transition layer 302, which then transfers the pressure to the wheel core 301, ultimately acting on the spindle 1. The elastic modulus of polyurethane material is in the tens of MPa range. In this embodiment, the elastic modulus of MC nylon is in the range of approximately 2000 MPa, and the elastic modulus of the steel wheel core 301 is greater than 200 GPa. Therefore, compared with the conventional polyurethane wheel structure in which the polyurethane layer 303 is directly cast onto the surface of the metal wheel core 301, the stress at the bonding surface between the polyurethane layer 303 and the modulus gradient transition layer 302 in this invention is significantly reduced: when a set of polyurethane wheelsets is subjected to a radial load of 32 tons, the stress at the bonding surface of the polyurethane layer 303 in the conventional structure is 14.6 MPa, while the stress at the bonding surface of the polyurethane layer 303 in this invention is 12.5 MPa, a decrease of approximately 14.4%, thereby greatly extending the fatigue life of the polyurethane wheel 3.

[0037] The above description is only a preferred embodiment of the present utility model and does not limit the implementation method and protection scope of the present utility model. Those skilled in the art should realize that all solutions obtained by equivalent substitutions and obvious changes made based on the description and illustrations of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A polyurethane wheel assembly, characterized in that, It includes a spindle, a connector, and polyurethane wheels. Several polyurethane wheels are mounted on the outer wall of the spindle and connected to the spindle through the connector. The outer walls of the several polyurethane wheels are all arc-shaped.

2. The polyurethane wheel assembly as described in claim 1, characterized in that, The polyurethane wheel is provided in four parts, with two polyurethane wheel pieces located on both sides symmetrically arranged, and two polyurethane wheel pieces located in the middle symmetrically arranged.

3. The polyurethane wheel assembly as described in claim 1, characterized in that, Each of the polyurethane wheel pieces includes a wheel core, a modulus gradient transition layer, and a polyurethane layer. The wheel core is connected to the spindle. The modulus gradient transition layer is disposed on the outer wall of the wheel core, and the polyurethane layer is disposed on the outer wall of the modulus gradient transition layer.

4. The polyurethane wheel assembly as described in claim 3, characterized in that, The outer wall of the wheel core is provided with several protrusions, and a groove is formed between two adjacent protrusions.

5. The polyurethane wheel assembly as described in claim 4, characterized in that, A first flange is provided on the inner wall of the wheel core, and a second flange is provided on the outer wall of the spindle. The first flange and the second flange are engaged.

6. The polyurethane wheel assembly as described in claim 5, characterized in that, The connector includes a stud and a nut. The stud connects the first flange and the second flange, and the nut is provided on the stud.

7. The polyurethane wheel assembly as described in claim 6, characterized in that, The connection between the double-ended stud and the nut is pre-coated with thread-locking agent.

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