A fixture for machining of automobile wheel hub

Abstract

The application discloses a clamp for automobile hub machining and belongs to the technical field of automobile hub manufacturing tooling. The clamp comprises a main shaft base, a forming section, a positioning module and a locking module. The locking module comprises a center pull rod penetrating through the main shaft base along an axial direction and a driving source for driving the center pull rod to move axially. The front end of the center pull rod is detachably connected with the rear end of the forming section through a hanging mechanism, so that the forming section is pulled rearward under the action of the axial pulling force provided by the driving source, and the two end face toothed discs are forced to engage. The rear end face of the forming section and the front end face of the main shaft base further form a pair of conical surface pairs in radial interference fit. The clamp can realize quick die changing and micron-level repeated positioning accuracy, can long-term maintain the connection rigidity and precision stability equivalent to an integrated core die under the working conditions of bearing huge radial force, axial force and thermal load, and can effectively prevent external pollutants.

Description

Technical Field

[0001] This invention relates to the field of tooling technology for automobile wheel manufacturing, and more specifically, to a fixture for processing automobile wheels. Background Technology

[0002] In the casting and spinning process of automotive wheel hubs, the mandrel, which determines the shape of the wheel hub's inner cavity, is the core component of the entire fixture system. In traditional processes, the mandrel, as part of the fixture, is an integral structure, directly locked to the spinning machine spindle via flanges and multiple high-strength bolts. When changing to a different size wheel hub mold, operators must manually remove all bolts, use a crane to lift the lower mold and replace it with the new one, and then align the outer diameter of the mandrel using a dial indicator to ensure its coaxiality with the spinning machine spindle's rotation center and minimize end face runout. This process typically takes 1 to 2 hours, heavily relies on the operator's experience, and in multi-variety, small-batch production, frequent mold changes cause significant downtime losses.

[0003] Therefore, a new solution is needed to address this problem. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to solve the above problems by providing a fixture for automobile wheel hub processing that can achieve rapid mold change and micron-level repeatability positioning accuracy, while maintaining connection rigidity and accuracy stability comparable to an integrated core mold under conditions of huge radial force, axial force and thermal load, and effectively protecting against external contaminants.

[0005] This invention achieves the above objective through the following technical solution: a fixture for machining automobile wheel hubs, comprising: The spindle base is fixedly connected to the spindle of the spinning machine; The forming section is coaxially arranged with the spindle base and is used to directly contact and form the workpiece; The positioning module includes intermeshing end face gears respectively disposed on the front end face of the spindle base and the rear end face of the forming section, which are used to realize the angular positioning and axial positioning of the forming section; The locking module includes a central tie rod that passes through the spindle base axially, and a drive source that drives the central tie rod to move axially. The front end of the central tie rod is detachably connected to the rear end of the forming section through a hooking mechanism, so that the forming section is pulled back and tightened under the axial tension provided by the drive source, so that the two end face gears are forced to mesh. The rear end face of the forming section and the front end face of the spindle base also form a pair of radially interference-fit conical surfaces. The conical surfaces are configured such that when the forming section meshes with the end face gear of the spindle base under the axial tension of the central tie rod, the conical surfaces generate radial interference to resist the radial load generated during processing.

[0006] In some embodiments, the conical pair is located radially peripheral to the end face gear meshing area.

[0007] In some embodiments: the conical pair is a pair of short conical mating surfaces, the short conical mating surfaces include an outer cone and an inner conical hole, the outer cone is disposed on the rear end face of the forming section, and the inner conical hole is opened on the front end face of the spindle base.

[0008] In some embodiments, the mounting mechanism includes: The hook connector is located at the front end of the center tie rod; A blocking element is provided at the rear end of the forming section. The blocking element is provided with a hook groove that allows the hook joint to enter axially and restricts its radial disengagement. After the hook-on joint enters the hook-on slot, the spindle of the spinning machine drives the central tie rod to rotate relative to the forming section by a preset angle, so that the hook-on joint and the blocking member are axially locked. The drive source then pulls the central tie rod backward to apply a locking force.

[0009] In some embodiments: it also includes an automatic media docking module, the automatic media docking module including at least one self-sealing quick-connect connector, the automatic media docking module including a male head embedded in the rear end face of the forming section and a female head embedded in the front end face of the spindle base; When the forming section is pulled to a position that fits against the spindle base, the male and female heads automatically connect and communicate. When the forming section is released and pulled out, the male and female heads automatically close.

[0010] In some embodiments, the front end face of the spindle base is provided with an overflow-proof cavity surrounding the self-sealing quick-change connector, for discharging leaked media from the connector to prevent it from entering the meshing area of ​​the end face gear plate.

[0011] In some embodiments: the locking module further includes a pressure closed-loop regulating device, the pressure closed-loop regulating device comprising: A tension sensor is used to detect the actual tension in the central tie rod in real time. A proportional pressure reducing valve is used to regulate the output pressure of the drive source; The controller is used to control the proportional pressure reducing valve to reduce the output pressure when the actual tension is greater than the preset tension value, and to control the proportional pressure reducing valve to increase the output pressure when the actual tension is less than the preset tension value, thereby maintaining the actual tension within the preset range.

[0012] In some embodiments: an unloading support ring is fitted on the outer circular surface of the spindle base near the spindle flange of the spinning machine. The inner ring of the unloading support ring is engaged with the outer circular surface of the spindle base, and its outer ring is used to fix it on the front end face of the spindle housing of the spinning machine so as to directly transmit part of the radial force generated during processing to the machine tool bed.

[0013] Compared with the prior art, the beneficial effects of the present invention are: Firstly, by using the hook-up mechanism at the front end of the central tie rod, hydraulic locking, and automatic media docking, rapid mold changing is achieved, significantly reducing downtime compared to traditional methods. Secondly, by innovatively introducing a radially interference-fit conical surface pair around the end face gear disk, force flow separation is achieved, where "axial / torque relies on the gear disk, and radial / bending moment relies on the conical surface." Under normal operating conditions, the end face gear disk only bears shear and axial tension and compression, while the radial force is rigidly resisted by the large-diameter conical surface pair, avoiding fretting wear and precision loss of the end face gear disk. Third, the coupling mechanism has a robust structure and a simple force flow path, which can withstand tens of tons of tension force to avoid failure of small parts; the pressure closed-loop adjustment device compensates for thermal expansion and contraction in real time, and works with hydraulic locks to prevent loosening, ensuring constant and safe locking force under normal working conditions. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0015] Figure 1 This is a schematic diagram of the overall structure according to some embodiments of this specification; Figure 2 These are partial structural cross-sectional schematic diagrams based on some embodiments of this specification, used to illustrate the connection between the spindle base and the forming section, as well as the positional relationship of the various internal components; Figure 3 This is a schematic diagram of the connection structure between the spindle base and the forming section according to some embodiments shown in this specification. Figure 1 The top cover of the unloading support ring is removed to reveal the internal structure of the conical pair and the load support ring. Figure 4 This is a schematic diagram of the connection structure between the spindle base and the forming section according to some embodiments shown in this specification. Figure 2 The removal of the unloading support ring and the tapered surface pair is used to demonstrate the connection between the forming section, the spindle base and the spindle flange. Figure 5This is a structural schematic diagram of the spindle base with the unloading support ring and conical surface pair removed according to some embodiments of this specification, used to show the positional relationship of the quick-change connector, anti-overflow cavity, humidity sensor and high-pressure air purging channel on the spindle base; Figure 6 This is a schematic diagram of the hydraulic locking and pressure closed-loop control system according to some embodiments of this specification.

[0016] Reference numerals: 1. Spindle base; 2. Forming section; 3. End face gear plate; 4. Conical pair; 41. Outer cone; 42. Inner cone hole; 5. Central tie rod; 6. Hanging joint; 7. Blocking component; 71. Hanging groove; 8. Drive source; 9. Quick-change joint; 10. Overflow prevention cavity; 11. Rotary joint; 12. Humidity sensor; 13. Thin-walled sleeve; 14. Unloading support ring; 20. High-pressure air purging channel; 25. Spindle flange. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. In this description, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention 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 the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0018] like Figures 1 to 6 As shown, one or more embodiments of this specification provide a fixture for machining automotive wheel hubs, the core of which is a quick-change mandrel, including a spindle base 1 and a forming section 2. The spindle base 1 is fixedly mounted on the spindle flange 25 of a spinning machine and is coaxial with the spindle of the spinning machine. A central through hole is machined inside the spindle base 1, through which a central tie rod 5 passes. The tail of the central tie rod 5 is connected to the piston rod of a drive source 8 (in this embodiment, a rotary hydraulic cylinder) mounted at the tail end of the spinning machine spindle, and can move axially with the piston rod and rotate synchronously with the spinning machine spindle. The forming section 2 is the forming part that directly contacts the aluminum alloy wheel hub, and its rear end face is opposite to the front end face of the spindle base 1.

[0019] Please refer to the structural details of the positioning module and the radial support conical surface pair 4. Figures 1 to 5On the rear end face of the forming section 2 and the front end face of the spindle base 1, intermeshing end face gears 3 are machined. These end face gears 3 employ a 90° or 60° tooth profile angle, and the number of teeth is selected between 72 and 144 teeth depending on the flange diameter. (See reference...) Figures 3 to 4 On the radial periphery of the meshing ring of the end face gear disk 3, the rear end face of the forming section 2 is machined with an outer cone 41, and the front end face of the spindle base 1 is correspondingly machined with an inner cone hole 42, forming a pair of 1:10 short conical surfaces 4. Through a grinding process, it is ensured that under the rated axial tensile force applied by the central tie rod 5, the end face gear disk 3 is fully meshed while the outer cone 41 and the inner cone hole 42 produce a radial interference of 0.01mm to 0.03mm. This grinding process is achieved by precisely controlling the "axial pressing allowance". For example, when the taper is 1:10, to achieve a radial interference of 0.02mm, the forming section 2 needs to be additionally axially pressed into the base 1 by 0.2mm on the basis of the end face gear disk's contact reference. This interference fit forms a highly rigid radial stop at the mating surface, directly transmitting the radial force to the base and protecting the inner end face gear disk 3.

[0020] Please refer to the details of the locking module's mounting mechanism. Figure 2 The front end of the central tie rod 5 is machined with a T-shaped hook connector 6. A blocking element 7 is fixed to the center hole of the forming section 2 by threads. The blocking element 7 has a hook groove 71, which includes an opening and a transverse locking groove. The opening of the hook groove 71 matches the shape of the hook connector 6.

[0021] During mold changing, the spinning machine spindle first stops via C-axis orientation, aligning the position of the coupling 6 with the opening of the coupling groove 71. A robotic arm or gantry pushes the forming section 2 towards the base 1, and the coupling 6 extends axially into the opening of the coupling groove 71 until it contacts the inner wall of the forming section 2, at which point there is still a gap between the end gears. Subsequently, the spinning machine spindle servo motor drives the spindle to rotate by a preset angle (e.g., 60°), causing the base 1 and the central tie rod 5 to rotate together, causing the transverse flange of the coupling 6 to enter the transverse locking groove of the coupling groove 71, thus completing the axial coupling. Finally, the control system sends a signal, oil enters the rod chamber of the hydraulic cylinder, the piston rod retracts, and the central tie rod 5 applies an axial pulling force of up to tens of tons to the blocking component 7, firmly tightening the forming section 2. Under this pulling force, the end gear 3 is forced into full engagement, and the outer cone 41 is simultaneously pulled into the inner cone hole 42 to form an interference fit. Upon release, the hydraulic cylinder first experiences a slight depressurization but not complete loss of pressure. Then, oil enters the rodless chamber of the hydraulic cylinder, pushing the piston rod forward and smoothly ejecting the forming section 2 forward through the front end face of the coupling 6, completing the demolding. Subsequently, the spindle of the spinning machine rotates in the opposite direction by the same angle, causing the coupling 6 to rotate out to the ejectible position.

[0022] Please refer to the automatic media docking module. Figure 1 and Figure 5 On the mating end faces of the spindle base 1 and the forming section 2, avoiding the area of ​​the gear plate and the conical surface, at least one pair of flush-end self-sealing quick-change connectors 9 are embedded. Each quick-change connector 9 includes a male and a female connector. When the two sections are hydraulically tightened and mated, the male and female connectors insert into each other and open their respective valve cores, thus opening the coolant passage. Around the quick-change connector 9, an annular anti-overflow cavity 10 is machined on the end face of the spindle base 1. If a minor leak occurs in the quick-change connector 9, the coolant will be confined within the anti-overflow cavity 10, preventing lateral diffusion to the end gear plate area. Furthermore, a humidity sensor 12 is installed within the anti-overflow cavity 10 to provide early warning and allow for timely replacement of the seals within the connector. Meanwhile, on the inner ring of the end face mating surface, a tangential high-pressure air purging channel 20 is opened on the spindle base 1. Several air holes are opened on the high-pressure air purging channel 20. When the mold is disengaged, high-pressure gas is ejected from the air holes to form an outward air curtain, preventing external aluminum chips and oil mist from intruding.

[0023] See Figure 2 A rotary joint 11 is coaxially mounted at the tail end of the central tie rod 5. The rotary joint 11 is common knowledge in the art. Its stationary housing and the rotating shaft core are connected by a high-precision mechanical seal (such as a silicon carbide-to-silicon carbide friction pair) or a gap seal to form a dynamic sealing cavity, which allows fluid (coolant or gas) to enter the rotating side from the stationary side without leakage or affecting the rotation of the shaft.

[0024] External supply of coolant is achieved through rotary joint 11. Specifically, a thin-walled sleeve 13 is coaxially fitted onto the central tie rod 5. The annular space between the sleeve and the central tie rod 5 is divided circumferentially into three independent axial channels by a partition: an inlet annular channel, a return annular channel, and a high-pressure gas annular channel. The front ends of the inlet and return annular channels are respectively connected to the interfaces of two self-sealing quick-change connectors 9 embedded in the front face of the spindle base 1 via flexible hoses. The rear ends of the two annular channels extend to the tail of the central tie rod 5 and are respectively connected to the corresponding channels on the rotating shaft of the rotary joint 11.

[0025] Thus, when the machine tool is working, the coolant enters the rotating annular inlet channel from the stationary external pipeline through the inlet of the rotary joint 11, flows forward to the quick-change joint 9, and circulates inside the forming section 2. After heat exchange, the coolant flows out from the forming section 2, flows backward back to the rotary joint 11 through the return annular channel, and is finally discharged from the outlet. When the central tie rod 5 moves axially in the annular channel, a flexible hose is used to achieve a space avoidance effect, ensuring a normal connection between the front end of the annular channel and the self-sealing quick-change joint 9 interface on the spindle base 1.

[0026] The front end of the high-pressure gas annular channel is connected to the high-pressure gas purging channel 20 via a hose. When the molding section 2 separates, the high-pressure gas enters the rotating high-pressure gas annular channel from the external pipeline through the liquid inlet of the rotary joint 11, and flows to the high-pressure gas purging channel 20 and is ejected through the air hole of the high-pressure gas purging channel 20.

[0027] Please refer to the pressure closed-loop control system. Figure 6 The hydraulic circuit consists of a hydraulic pump station, a proportional pressure reducing valve, a hydraulically controlled check valve, a pressure relay, a three-position four-way solenoid directional valve, and a relief valve. The hydraulic pump station includes an oil tank, a hydraulic pump, and a drive motor, providing a stable pressure oil source for the system. A force sensor (such as a strain gauge force sensor) is installed at the piston rod connection of the hydraulic cylinder or at the cylinder end cap to detect the actual axial tension acting on the central tie rod 5 in real time. The sensor signal is transmitted to a controller (such as a PLC). The controller receives the feedback signal from the force sensor, compares it in real time with an internally preset target tension value, and outputs a control signal to the proportional pressure reducing valve. This adjusts the current of the proportional pressure reducing valve, thereby precisely controlling the pressure in the rod chamber of the hydraulic cylinder.

[0028] Simultaneously, a three-position four-way solenoid directional valve controls the flow of pressurized oil, achieving three working positions: locked, released, and pressure-holding. A pilot-operated check valve is a bidirectional pilot-operated check valve used to close the hydraulic cylinder's working chamber in the neutral position of the directional valve or in case of accidental pressure loss. A pressure relay monitors the system pressure and sends an alarm signal to the controller when the pressure falls below a safe threshold. A relief valve is connected in parallel in the oil circuit as a mechanical overload protection, limiting the system's maximum pressure and preventing pressure exceedances under extreme thermal expansion.

[0029] The resulting oil circulation path is as follows: The hydraulic pump in the hydraulic pump station draws oil from the oil tank, converts low-pressure oil into high-pressure oil, and outputs it to the system. An overflow valve is installed at the pump outlet to limit the maximum operating pressure of the entire system, providing mechanical overload protection.

[0030] High-pressure oil first enters the inlet of the proportional pressure reducing valve. Based on the electrical signal from the controller, the proportional pressure reducing valve precisely adjusts its outlet pressure to the required value (e.g., outputting extremely low pressure in the gentle pull position and full pressure in the locking position).

[0031] The precisely pressurized oil enters the inlet (P port) of the three-position four-way solenoid directional valve. This directional valve has three operating positions: Left position (locked position): Electromagnet a is energized, connecting port P to port A and port B to port T (oil tank). Pressure oil flows through port A, opening the left check valve of the hydraulic control check valve and entering the rod chamber (rear end of the piston) of the rotary hydraulic cylinder. This pushes the piston rod back, causing the central tie rod 5 to move backward, performing the tightening action. Simultaneously, oil in the rodless chamber flows back to the oil tank through port B.

[0032] Right position (released position): Electromagnet b is energized, connecting ports P and B, and ports A and T. Pressure oil flows through port B, opening the right-side check valve of the hydraulic control check valve, entering the rodless chamber (piston front end) of the rotary hydraulic cylinder, pushing the piston rod out, and causing the central pull rod 5 to move forward, performing the release and ejection actions. Simultaneously, oil in the rod chamber flows back to the oil tank through port A.

[0033] Neutral position (pressure holding / safety position): Electromagnets a and b are both de-energized, port P is closed, and ports A and B are both connected to port T. At this time, both the left and right check valves of the hydraulic control check valve are closed under the action of spring force, locking the oil in both the rod-side and rodless sides of the rotary hydraulic cylinder in both directions. The piston rod is fixed in its current position and cannot move. This ensures that the locking force can be stably maintained even if the system suddenly loses power or the pump station stops.

[0034] The piston rod of the rotary hydraulic cylinder moves linearly under the drive of pressurized oil, and drives the central tie rod 5 to move through a mechanical connection, thereby applying tension to the forming section 2. A tension sensor installed at the piston rod connection senses the magnitude of the axial force in real time and converts it into an electrical signal.

[0035] A pressure relay is connected in parallel in the oil inlet circuit to monitor the system pressure in real time. Once the pressure is detected to drop below a preset danger threshold due to leakage or other faults, the pressure relay will immediately send a switching signal to the controller, which will then execute safety procedures such as alarm and shutdown.

[0036] The closed-loop control circuit flow is as follows: The operator sets the required locking force target value in the controller (PLC). This value corresponds to a target oil pressure value through a mechanical conversion relationship, which serves as the reference for closed-loop control.

[0037] After spinning begins, the tension sensor installed on the piston rod of the hydraulic cylinder continuously and in real time measures the actual axial tension borne by the central tie rod 5 and converts this physical quantity into an electrical signal.

[0038] The tension sensor feeds back the real-time tension signal to the controller. The controller's internal program compares this signal with the preset target tension value in real time and calculates the deviation value (a positive value indicates that the current tension is too high, and a negative value indicates that it is too low).

[0039] The controller uses PID (proportional-integral-derivative) and other control algorithms to calculate the deviation based on its magnitude and direction, generates a corrected control signal, and outputs it to the amplifier of the proportional pressure reducing valve.

[0040] The proportional pressure reducing valve automatically adjusts its valve core opening according to the received control signal, thereby precisely changing its outlet oil pressure.

[0041] When thermal expansion causes the locking tension to rise abnormally, the sensor reports that the tension is too high, the controller output signal decreases, the proportional pressure reducing valve reduces the outlet pressure, causing the pressure in the rod chamber of the hydraulic cylinder to drop, and the tension subsequently falls back to the target value.

[0042] When cooling contraction causes an abnormal drop in locking tension, the sensor reports that the tension is too low, the controller outputs an increased signal, the proportional pressure reducing valve increases the outlet pressure, causing the pressure in the rod chamber of the hydraulic cylinder to rise, and the tension subsequently recovers to the target value.

[0043] The aforementioned "detection-feedback-comparison-adjustment" process continuously cycles at millisecond intervals, forming a dynamic closed-loop negative feedback control system that ensures that the locking force can be stably and actively compensated and maintained within the set range under normal thermal conditions.

[0044] Please see Figure 3 An unloading support ring 14 is installed on the outer circular surface of the spindle base 1 near the flange end. The inner ring of the unloading support ring 14 is fitted onto the outer circular precision journal of the base 1, and a high-precision needle roller bearing is used as the rolling element. Its outer ring is fixedly installed on the front end face of the spinning machine spindle housing. When the overhanging forming section 2 is subjected to radial extrusion force, part of the force flow path is transmitted directly to the machine bed with excellent rigidity through the forming section 2, the tapered pair 4, the spindle base 1, and the unloading support ring 14. This significantly reduces the load transmitted to the main bearing inside the spinning machine spindle and reduces the bending deformation of the spindle.

[0045] Working principle: When changing the mold, the robotic arm holds the new forming section 2, aligns the opening of the mounting groove 71 of the blocking member 7 with the mounting head 6, and slowly pushes it in. After the mounting head 6 enters the mounting groove 71 of the blocking member 7 axially, there is still a gap between the forming section 2 and the end face gear plate 3 of the main shaft base 1.

[0046] Subsequently, the servo motor of the spinning machine spindle executes a pre-set rotational action, causing the coupling 6 and the blocking component 7 to complete the rotational engagement. The hydraulic system is activated, the proportional pressure reducing valve outputs pressure, the hydraulic cylinder pulls back, and a set tension is applied through the central tie rod 5, driving the forming section 2 further towards the spindle base 1 and tightly tightening the forming section 2. During this process, the two end face gear discs 3 are forced into full meshing, achieving precise axial and angular positioning. At the same time, the outer cone 41 is pulled into the inner cone hole 42, generating radial interference and forming rigid radial support. Simultaneously, the quick-change coupling 9 automatically engages.

[0047] Spinning begins, with immense spinning pressure acting on forming section 2. Axial force and rotational torque are transmitted through the end face gear 3; radial extrusion force and overturning moment are mainly transmitted through the outer large-diameter conical joint 4; the constant locking force provided by the central tie rod 5 ensures that the above positioning surfaces are always tightly fitted. The controller monitors the tension sensor values ​​in real time and adjusts the hydraulic pressure to compensate for thermal effects. The unloading support ring 14 bypasses part of the radial force to the bed.

[0048] When processing is complete and mold changing is required, the controller instructs the hydraulic system to slightly depressurize, then the hydraulic cylinder pushes forward, and the central tie rod 5 smoothly ejects the forming section 2. At the moment of disengagement, the self-sealing quick-change connector 9 automatically closes, and high-pressure gas is ejected from the nozzle of the high-pressure air purging channel 20 to clean the mating surface and form an airflow barrier. Subsequently, the servo motor of the spinning machine spindle rotates in the opposite direction to unlock the coupling 6.

[0049] It should be clarified that: the toothed disc 3 (rat tooth disc), as a precision indexing and positioning element, has tooth profile design, meshing principle, and automatic centering characteristics that are common knowledge in the field; the large-tapered conical surface and end face double-contact positioning principle adopted by the HSK tool holder interface is common knowledge in the field; the principle of pressure holding and anti-loosening achieved by the hydraulic control check valve and pressure relay in the hydraulic locking circuit is common knowledge in the field; and the method of forming a closed-loop control by the proportional pressure reducing valve and force sensor is common knowledge in the field. The specific structure, model selection, and control logic of the above common knowledge will not be elaborated here.

[0050] The aforementioned parameters, such as tooth profile angle, number of teeth, taper, interference fit, locking tension, and temperature compensation threshold, can all be conventionally optimized and adjusted according to the actual size and load of the spun workpiece, and can be determined by those skilled in the art without creative effort. The self-centering principle of the end face gear disk 3 is common knowledge in the field. The core protection scope of this application lies in the clearly defined spatial layout and definite mechanical connection relationship of each component. This layout does not depend on ideal working conditions and can achieve the aforementioned functions under normal use.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fixture for machining automobile wheel hubs, characterized in that, include: The spindle base is fixedly connected to the spindle of the spinning machine; The forming section is coaxially arranged with the spindle base and is used to directly contact and form the workpiece; The positioning module includes intermeshing end face gears respectively disposed on the front end face of the spindle base and the rear end face of the forming section, which are used to realize the angular positioning and axial positioning of the forming section; The locking module includes a central tie rod that passes through the spindle base axially, and a drive source that drives the central tie rod to move axially. The front end of the central tie rod is detachably connected to the rear end of the forming section through a hooking mechanism, so that the forming section is pulled back and tightened under the axial tension provided by the drive source, so that the two end face gears are forced to mesh. The rear end face of the forming section and the front end face of the spindle base also form a pair of radially interference-fit conical surfaces. The conical surfaces are configured such that when the forming section meshes with the end face gear of the spindle base under the axial tension of the central tie rod, the conical surfaces generate radial interference to resist the radial load generated during processing.

2. The fixture for machining automobile wheel hubs according to claim 1, characterized in that: The conical pair is located radially outside the meshing area of ​​the end face gear disk.

3. A fixture for machining automobile wheel hubs according to claim 2, characterized in that: The conical surface pair consists of a pair of short conical mating surfaces, each including an outer cone and an inner conical hole. The outer cone is located on the rear end face of the forming section, and the inner conical hole is located on the front end face of the spindle base.

4. A fixture for machining automobile wheel hubs according to claim 1, characterized in that: The mounting mechanism includes: The hook connector is located at the front end of the center tie rod; A blocking element is provided at the rear end of the forming section. The blocking element is provided with a hook groove that allows the hook joint to enter axially and restricts its radial disengagement. After the hook-on joint enters the hook-on slot, the spindle of the spinning machine drives the central tie rod to rotate relative to the forming section by a preset angle, so that the hook-on joint and the blocking member are axially locked. The drive source then pulls the central tie rod backward to apply a locking force.

5. A fixture for machining automobile wheel hubs according to claim 4, characterized in that: The locking module is driven by a hydraulic cylinder located at the tail end of the spinning machine spindle. The hydraulic circuit of the hydraulic cylinder is equipped with a hydraulically controlled check valve and a pressure relay to maintain the locking force when pressure is lost.

6. A fixture for machining automobile wheel hubs according to claim 1, characterized in that: It also includes an automatic media docking module, which includes at least one self-sealing quick-connect connector, which includes a male head embedded in the rear end face of the forming section and a female head embedded in the front end face of the spindle base. When the forming section is pulled to a position that fits against the spindle base, the male and female heads automatically connect and communicate. When the forming section is released and pulled out, the male and female heads automatically close.

7. A fixture for machining automobile wheel hubs according to claim 6, characterized in that: The front end face of the spindle base is provided with an overflow prevention cavity surrounding the quick-change connector, which is used to discharge the leaked medium from the quick-change connector to prevent it from entering the meshing area of ​​the end face gear plate.

8. A fixture for machining automobile wheel hubs according to claim 1, characterized in that: The locking module further includes a pressure closed-loop regulating device, which includes: A tension sensor is used to detect the actual tension in the central tie rod in real time. A proportional pressure reducing valve is used to regulate the output pressure of the drive source; The controller is used to control the proportional pressure reducing valve to reduce the output pressure when the actual tension is greater than the preset tension value, and to control the proportional pressure reducing valve to increase the output pressure when the actual tension is less than the preset tension value, thereby maintaining the actual tension within the preset range.

9. A fixture for machining automobile wheel hubs according to claim 1, characterized in that: An unloading support ring is fitted on the outer circular surface of the spindle base near the spindle flange of the spinning machine. The inner ring of the unloading support ring mates with the outer circular surface of the spindle base, and its outer ring is used to fix it on the front end face of the spindle housing of the spinning machine so as to directly transmit part of the radial force generated during processing to the machine tool bed.

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