Numerically controlled automatic feed honing machine and control method thereof

Abstract

The patent relates to the technical field of automatic honing machining, in particular to a numerical control automatic feeding honing machine and a control method thereof, which comprises a machine tool base assembly, a protective cover assembly, a pneumatic knocking system, a power system, a servo feeding system, a cooling system, a honing spindle assembly, a workpiece clamp and a control system, the honing spindle assembly is installed on the power system, the honing spindle assembly comprises a honing sleeve, a taper mandrel and a push rod, the pneumatic knocking system comprises a pneumatic cylinder and a proportional valve, the power system comprises a torque sensor assembly, and the servo feeding system comprises a force sensor; the patent precisely controls the knocking force through the pneumatic knocking system and the proportional valve, automatically adjusts the diameter of the honing sleeve, greatly reduces the labor intensity of workers, and solves the problem that the existing manual honing machine needs to take the workpiece out of the honing machine for measurement multiple times, repeatedly controls the honing feeding according to the measurement results, judges whether the workpiece is qualified, and seriously affects the machining efficiency of honing.

Description

Technical Field

[0001] This invention relates to the field of automatic honing technology, specifically a CNC automatic feed honing machine and its control method. Background Technology

[0002] Honing is a finishing process that uses an oilstone on a honing head to polish the inner surface of a workpiece. It is widely used in the machining of precision parts such as hydraulic components, internal combustion engine injectors, and cylinder liners. Honing is primarily accomplished by three basic elements: the rotational motion of the spindle, the reciprocating linear motion of the workpiece, and the radial pressure feed of the honing head. However, the spindle rotation is not matched with the reciprocating linear motion. Radial pressure feed still relies on manual tapping or manual feeding. Whether the workpiece is qualified after honing still requires repeated measurement with a pneumatic gauge and multiple honing cycles. During manual honing, the radial pressure feed is still controlled by the worker based on experience. To judge whether the workpiece is qualified, the workpiece needs to be removed from the honing machine multiple times for measurement. After measurement, the honing feed needs to be repeatedly controlled based on the results to achieve qualification. Manual honing severely affects the honing efficiency. Summary of the Invention

[0003] The present invention aims to provide a CNC automatic feed honing machine and its control method to solve the problem that existing manual honing machines require the workpiece to be removed from the honing machine multiple times for measurement, and the honing feed is repeatedly controlled based on the measurement results to determine whether the workpiece is qualified, which seriously affects the honing processing efficiency.

[0004] To achieve the above objectives, the basic solution of the present invention is as follows: a CNC automatic feed honing machine includes a machine tool base assembly, a protective cover assembly, a pneumatic striking system, a power system, a servo feed system, a cooling system, a honing spindle assembly, a workpiece fixture, and a control system, wherein the protective cover assembly, the pneumatic striking system, the power system, the servo feed system, the cooling system, the honing spindle assembly, the workpiece fixture, and the control system are all mounted on the machine tool base assembly; The honing spindle assembly is mounted on the power system, and the workpiece fixture is mounted on the servo feed system; the pneumatic striking system, the power system, and the honing spindle assembly are arranged coaxially; the honing spindle assembly includes a honing sleeve, a tapered mandrel, and a push rod, the tapered mandrel is connected to the push rod, and the honing sleeve is fitted over the outside of the tapered mandrel; The pneumatic striking system includes a cylinder and a proportional valve. The proportional valve is used to control the air pressure entering the cylinder. The cylinder is used to strike the push rod forward or backward to drive the tapered mandrel to move axially and control the change in the diameter of the honing sleeve. The power system includes a torque sensor assembly, which is used to collect the torque value T in real time during the honing process; The servo feed system includes a force sensor, which is used to collect the axial feed force during the honing process in real time. The control system includes a CNC system and a host computer. The CNC system is used to control the reciprocating motion of the servo feed system, the rotational motion of the power system, and the striking action of the pneumatic striking system. The host computer is used to collect the torque value T, axial feed force, and coordinate values ​​of the CNC system in real time and automatically determine whether the honing process is qualified.

[0005] Furthermore, the pneumatic striking system also includes an impact bracket, a first impact block, a cylinder impact head, a linear guide rail, a cylinder base, a second impact block, and a limiting block; the cylinder impact head is connected to the output end of the cylinder, and the cylinder is mounted on the machine tool base assembly via the cylinder base; the first impact block and the second impact block are respectively mounted on both sides of the impact bracket, and the first impact block has a central hole for the push rod to pass through; the limiting block is used to limit the extreme position of the push rod's backward movement.

[0006] Furthermore, the power system also includes a motor, a coupling, a small synchronous pulley, a synchronous belt, a shim block, a driven shaft, a bearing housing, and a power spindle assembly; the motor is connected to the input end of the torque sensor assembly via the coupling, and the small synchronous pulley is installed at the output end of the torque sensor assembly; the driven shaft is installed in the bearing housing, and one end of the driven shaft is connected to the small synchronous pulley; the small synchronous pulley is connected to the power spindle assembly via the synchronous belt; the driven shaft and the bearing housing constitute a driven support structure to eliminate the influence of the lateral force of the synchronous belt on the measurement accuracy of the torque sensor assembly.

[0007] Furthermore, the power spindle assembly includes a lubricating oil connector, a hollow stepped shaft, a one-way thrust ball bearing, a ball bearing, a spindle housing, a spindle base, a transition sleeve, a bearing lock nut, and a timing pulley. The lubricating oil connector is threaded onto the spindle housing, which is connected to the spindle base. The hollow stepped shaft is supported within the spindle housing by one-way thrust ball bearings and ball bearings arranged at both ends. The transition sleeve is installed at the end of the hollow stepped shaft for connecting to the honing spindle assembly. The bearing lock nut is installed on the hollow stepped shaft and presses the bearing. The timing pulley is installed on the hollow stepped shaft.

[0008] Furthermore, the servo feed system also includes a motion module, a module connecting plate, a connecting block, a slider bracket, a linear guide rail, and a connecting plate; the motion module includes a main module and a sub-module, and the main module and the sub-module maintain synchronous movement; one end of the connecting block is connected to the module connecting plate, and the other end of the connecting block is connected to one end of the force sensor; the other end of the force sensor is connected to the slider bracket; the slider bracket is mounted on the linear guide rail, and the linear guide rail is mounted on the module connecting plate; the connecting plate connects the two slider brackets, and the workpiece fixture is mounted on the connecting plate.

[0009] Furthermore, the honing spindle assembly also includes a transmission sleeve, a limiting screw, a positioning pin, a transition sleeve, a large nut, a tightening nut, and a hexagonal thin nut; the push rod clearance is installed inside the transmission sleeve, the limiting screw is installed on the side wall of the transmission sleeve and extends into the straight groove of the push rod; the transition sleeve clearance is installed at the end of the transmission sleeve, the large nut connects the transition sleeve to the transmission sleeve and retains axial floating clearance; the honing sleeve is installed on the transition sleeve by the tightening nut and the hexagonal thin nut and remains in a floating state; the honing sleeve is a collet structure with no circumferential slots, which achieves radial expansion under the tension of the tapered mandrel, and the tapered mandrel recovers its original shape by its own elasticity when it retracts.

[0010] Furthermore, the cooling system comprises a bamboo-joint tube, a first ball valve, a cooling oil fixing seat, a straight connector, a first hydraulic hose, a tee connector, an oil receiving groove assembly, a second hydraulic hose, a third hydraulic hose, a second ball valve, a cooling oil pump, a filter assembly, and a cooling oil tank. The bamboo-joint tube is mounted on the first ball valve, and the first ball valve is mounted on the cooling oil fixing seat. The straight connector, the first hydraulic hose, and the tee connector are connected in sequence. The straight connector is connected to the cooling oil fixing seat, and the other two ends of the tee connector are connected to the second and third hydraulic hoses. The second hydraulic hose is connected to the cooling oil pump, and the second ball valve is mounted on the third hydraulic hose. The second ball valve is mounted on the cooling oil tank. The cooling oil pump is mounted on the cooling oil tank, and the filter assembly is mounted on the cooling oil tank. The oil receiving groove assembly is connected to the interior of the filter assembly. The oil receiving groove assembly, the cooling oil fixing seat, and the cooling oil tank are mounted on the machine tool base assembly.

[0011] A control method for a CNC automatic feed honing machine, characterized in that: it employs a CNC automatic feed honing machine as described in any one of claims 1-7, and includes the following steps: S1. Parameter acquisition: The torque value T during the honing process is acquired in real time through the torque sensor assembly, the axial feed forces F1 and F2 on both sides are acquired in real time through the force sensor, and the coordinate values ​​of the CNC system are acquired in real time through the host computer to obtain the axial length L of the honing sleeve in the workpiece. S2. Contact Area Calculation: Based on the radius r and axial length L of the honing sleeve, calculate the real-time contact area S between the honing sleeve and the workpiece's inner hole: S = πr 2 L; S3. Stress parameter calculation: Based on the collected torque value T and contact area S, calculate the torsional shear stress τ=T / S; based on the collected axial feed forces F1 and F2 and contact area S, calculate the axial circumferential pressure P=(F1+F2) / S. S4. Automatic feed adjustment: The real-time calculated torsional shear stress τ and axial circumferential pressure P are compared with the preset target values. The control system controls the pneumatic striking system to strike the push rod forward or backward, adjusting the diameter of the honing sleeve so that the torsional shear stress τ and axial circumferential pressure P are maintained within the set range. S5. Automatic qualification judgment: During the honing process, the fluctuation of torsional shear stress τ and axial circumferential pressure P with the honing reciprocating motion is monitored in real time. When the difference between the peak and valley of torsional shear stress τ and the difference between the peak and valley of axial circumferential pressure P are both less than their respective set thresholds, the workpiece is judged to be qualified for honing. S6. Processing complete: After passing the inspection, the control system controls the pneumatic striking system to strike backward to retract the honing sleeve, the servo feed system returns to the standby position, the power system stops rotating, and the processing is complete.

[0012] The beneficial effects of this patent are: (1) This patent realizes the fully automatic adjustment of the radial feed of the honing sleeve. The pneumatic striking system, combined with the proportional valve, precisely controls the striking force and automatically adjusts the diameter of the honing sleeve. There is no need for manual striking, which greatly reduces the labor intensity of workers and improves the processing efficiency and product consistency.

[0013] (2) This patent realizes closed-loop control of honing. By collecting torque, feed force and position coordinates in real time, it calculates torsional shear stress and axial circumferential pressure, and dynamically adjusts the honing feed accordingly to form a complete closed-loop control system, ensuring that the processing process is stable and controllable.

[0014] (3) This patent realizes the automatic judgment of honing qualification. Based on the correspondence between the fluctuation amplitude of torsional shear stress and axial circumferential pressure and the accuracy of the inner hole of the workpiece, the honing qualification is automatically judged by monitoring the difference between the peak and valley. There is no need to repeatedly disassemble the workpiece for measurement, avoiding the error caused by repeated clamping, and significantly improving the processing efficiency and processing accuracy.

[0015] (4) This patent has high detection accuracy. The power system adopts a driven shaft structure to eliminate the influence of belt lateral force on torque sensor. The servo feed system adopts linear guide rail to offset the interference of gravity on force sensor. The honing spindle assembly adopts a floating centering structure to ensure that the honing sleeve runout is minimal. Multiple designs work together to ensure the accuracy of detection data and provide a reliable basis for closed-loop control and qualification judgment. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is an exploded view of the protective cover assembly in an embodiment of the present invention; Figure 3 This is an exploded view of the pneumatic striking system in an embodiment of the present invention; Figure 4 This is an exploded view of the power system components in an embodiment of the present invention; Figure 5 This is an exploded view of the power spindle assembly in an embodiment of the present invention; Figure 6 This is an exploded view of the servo feed system in an embodiment of the present invention; Figure 7 This is a schematic diagram of the specific structure of the machine tool base assembly in an embodiment of the present invention; Figure 8 This is an exploded view of the cooling system in an embodiment of the present invention; Figure 9 This is an exploded view of the honing spindle assembly in an embodiment of the present invention; Figure 10 This is an exploded view of the workpiece fixture in an embodiment of the present invention; Figure 11 This is an exploded view of the needle valve body fixing clamp in an embodiment of the present invention. 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. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The reference numerals in the accompanying drawings include: 1. Protective cover assembly; 2. Pneumatic impact system; 3. Power system; 4. Servo feed system; 5. Machine tool base assembly; 6. Cooling system; 7. Honing spindle assembly; 8. Workpiece fixture; 9. Control system; 1-1. Protective cover top cover; 1-2. Side protective cover; 1-3. Slide rail; 1-4. Oil baffle; 2-1. Impact bracket; 2-2. First impact block; 2-3. Cylinder impact head; 2-4. Linear guide rail; 2-5. Cylinder base; 2-6. Cylinder; 2-7. Second impact block; 2-8. Limiting block. 8. Motor 3-1, Coupling 3-2, Torque Sensor Assembly 3-3, Small Synchronous Belt Pulley 3-4, Synchronous Belt 3-5, Raising Block 3-6, Driven Shaft 3-7, Bearing Housing 3-8, Power Spindle Assembly 3-9, Lubricating Oil Connector 3-9-1, Hollow Stepped Shaft 3-9-2, One-Way Thrust Ball Bearing 3-9-3, Ball Bearing 3-9-4, Bearing Cover 3-9-5, Transition Sleeve 3-9-6, Spindle Base 3-9-7, Spindle Housing 3-9-8, Bearing Lock Nut 3-9-9, etc. 3-9-10 Stepper pulley, 4-1 Motion module, 4-2 Module connecting plate, 4-3 Connecting block, 4-4 Force sensor, 4-5 Slider bracket, 4-6 Linear guide rail, 4-7 Connecting plate, 6-1 Bamboo tube, 6-2 First ball valve, 6-3 Cooling oil fixing seat, 6-4 Straight connector, 6-5 First hydraulic hose, 6-6 T-connector, 6-7 Oil receiving groove assembly, 6-8 Second hydraulic hose, 6-9 Third hydraulic hose, 6-10 Second ball valve, 6-11 Cooling oil pump, 6-12 Filter assembly. 2. Cooling oil tank 6-13, tightening nut 7-1, honing sleeve 7-2, hexagonal thin nut 7-3, large nut 7-4, transition sleeve 7-5, tapered mandrel 7-6, positioning pin 7-7, transmission sleeve 7-8, limit screw 7-9, push rod 7-10, knurled high head screw 8-1, adjusting pin 8-2, clamp body 8-3, outer ring 8-4, needle valve body fixing clamp 8-5, positioning pin 8-6, clamp body 8-5-1, positioning pin 8-5-2, needle valve body 8-5-3, pressure cap 8-5-4. Example

[0019] The basics are as follows: Figure 1 The image shows a CNC automatic feed honing machine, comprising a protective cover assembly 1, a pneumatic striking system 2, a power system 3, a servo feed system 4, a machine tool base assembly 5, a cooling system 6, a honing spindle assembly 7, a workpiece clamp 8, and a control system 9. The protective cover assembly 1, pneumatic striking system 2, power system 3, servo feed system 4, and cooling system 6 are all mounted on the machine tool base assembly 5 via screws; the honing spindle assembly 7 is mounted on the power system 3 via flat-end set screws, and the workpiece clamp 8 is mounted on the servo feed system 4 via screws.

[0020] Combination Figure 2As shown, the protective cover assembly 1 includes a protective cover top cover 1-1, side protective covers 1-2, slide rails 1-3, and oil baffles 1-4. The protective cover top cover 1-1 is installed on the top of the side protective covers 1-2 by screws. The two side slide rails 1-3 are installed on the front of the side protective covers 1-2 by screws. The oil baffles 1-4 are installed on the two side slide rails 1-3 by screws and can slide freely along the slide rails 1-3. During processing, the oil baffles 1-4 extend to prevent cooling oil from splashing; when loading and unloading materials, the oil baffles 1-4 are pushed open for easy operation.

[0021] Combination Figure 3 As shown, the pneumatic impact system 2 includes an impact bracket 2-1, a first impact block 2-2, a cylinder impact head 2-3, a linear guide rail 2-4, a cylinder base 2-5, a cylinder 2-6, a second impact block 2-7, and a limiting block 2-8. The cylinder 2-6 is a double-headed cylinder. The cylinder impact head 2-3 is threadedly connected to the ends of the two piston rods of the cylinder 2-6. The cylinder 2-6 is mounted on the cylinder base 2-5 with screws. The cylinder base 2-5 is mounted on the machine tool base assembly 5 with screws. The first impact block 2-2 and the second impact block 2-7 are respectively mounted on the front and rear sides of the impact bracket 2-1 with screws. The first impact block 2-2 has a central hole. The linear guide rail 2-4 is mounted on the bottom of the impact bracket 2-1 to provide axial guidance for the impact bracket 2-1. The limiting block 2-8 is mounted on the cylinder base 2-5 to limit the extreme position of the impact bracket 2-1's backward movement.

[0022] The working principle of the pneumatic striking system 2 is as follows: the proportional valve adjusts the air pressure entering the cylinder 2-6 according to the signal output by the control system. The piston rod of the cylinder 2-6 extends or retracts, and strikes the second impact block 2-7 or the first impact block 2-2 through the cylinder impact head 2-3, which drives the impact bracket 2-1 to move forward or backward along the linear guide rail 2-4.

[0023] Combination Figure 4As shown, the power system 3 includes a motor 3-1, a coupling 3-2, a torque sensor assembly 3-3, a small synchronous pulley 3-4, a synchronous belt 3-5, a shim block 3-6, a driven shaft 3-7, a bearing housing 3-8, and a power spindle assembly 3-9. The motor 3-1, torque sensor assembly 3-3, power spindle assembly 3-9, bearing housing 3-8, and shim block 3-6 are all fixed to the base assembly 5 with screws. The output shaft of the motor 3-1 is connected to the input end of the torque sensor assembly 3-3 via the coupling 3-2. The torque is transmitted by keyway fitting and circumferential screw locking. The small synchronous pulley 3-4 is installed at the output end of the torque sensor assembly 3-3 by screws and keyways. The driven shaft 3-7 is installed in the bearing housing 3-8 by interference fit. The other end of the driven shaft 3-7 extends into the center hole of the small synchronous pulley 3-4 to provide rotational support for the small synchronous pulley 3-4. The cylinder 2-6 in the pneumatic striking system 2, the power spindle assembly 3-9 in the power system 3, and the honing spindle assembly 7 are arranged coaxially.

[0024] The innovation of this power system lies in the design of a driven support structure consisting of a driven shaft 3-7 and a bearing housing 3-8. The lateral force generated by the tensioning of the synchronous belt 3-5 is entirely borne by the driven shaft 3-7 and the bearing housing 3-8, and will not be transmitted to the torque sensor assembly 3-3. This eliminates the interference of the belt's lateral force on torque measurement, making the torque value detected by the torque sensor closer to the actual honing torque and significantly improving the accuracy of torque detection.

[0025] Combination Figure 5As shown, the power spindle assembly 3-9 includes a lubricating oil connector 3-9-1, a hollow stepped shaft 3-9-2, a one-way thrust ball bearing 3-9-3, a ball bearing 3-9-4, a bearing cap 3-9-5, a transition sleeve 3-9-6, a spindle base 3-9-7, a spindle housing 3-9-8, a bearing lock nut 3-9-9, and a synchronous pulley 3-9-10. The lubricating oil connector 3-9-1 is threaded onto the spindle housing 3-9-8 for injecting lubricating oil to lubricate the bearings. The spindle housing 3-9-8 is connected and fixed to the spindle base 3-9-7 by screws. The hollow stepped shaft 3-9-2 is installed inside the spindle housing 3-9-8, and its two ends are respectively connected by one-way thrust ball bearings 3-9-3, 3-9-4, 3-9-5, 3-9-6, 3-9-7, 3-9-8, 3-9-9, and 3-9-10. Supported by bearings 3-9-3 and 3-9-4, bearing caps 3-9-5 are mounted on both ends of the spindle housing 3-9-8 with screws for axial positioning of the bearing outer ring. Transition sleeve 3-9-6 is mounted on the left end of the hollow stepped shaft 3-9-2 with set screws for connecting the honing spindle assembly 7. The side of transition sleeve 3-9-6 is designed with an inclined plane. Bearing lock nut 3-9-9 is threaded onto the hollow stepped shaft 3-9-2 for pressing the bearing inner ring to achieve axial locking. Synchronous pulley 3-9-10 is mounted on the right end of the hollow stepped shaft 3-9-2 with side set screws. Small synchronous pulley 3-4 is connected to synchronous pulley 3-9-10 via synchronous belt 3-5.

[0026] Both ends of the power spindle assembly 3-9 adopt a combined support structure of one-way thrust ball bearing and ball bearing, which not only ensures the high rotational accuracy of the spindle, but also can withstand the bidirectional axial impact force from the pneumatic hammering system, meeting the working conditions of automatic feed honing.

[0027] Combination Figure 6As shown, the servo feed system 4 includes a motion module 4-1, a module connecting plate 4-2, a connecting block 4-3, a force sensor 4-4, a slider bracket 4-5, a linear guide rail 4-6, and a connecting plate 4-7. The motion module 4-1 adopts a dual-module structure with synchronous drive to ensure smooth motion. The module connecting plate 4-2 is horizontally mounted on the slider of the motion module 4-1 with screws. One end of the connecting block 4-3 is fixedly connected to the module connecting plate 4-2 with screws, and the other end is connected to one end of the force sensor 4-4 with screws. The other end of the force sensor 4-4 is connected to the slider bracket 4-5 with screws. The slider bracket 4-5 is mounted on the slider of the linear guide rail 4-6 with screws. The linear guide rail 4-6 is fixed to the module connecting plate 4-2 with screws. The linear guide 4-6 is aligned with the feed direction of the motion module. The connecting plate 4-7 is connected between the left and right slider supports 4-5 by screws. The workpiece fixture 8 is mounted on the connecting plate 4-7. The linear guide 4-6 bears the entire weight of the connecting plate 4-7, the slider support 4-5, the workpiece, and the fixture. The force sensor 4-4 only bears the axial force in the feed direction, eliminating the influence of lateral forces such as gravity on the measurement accuracy of the force sensor. This ensures that the force value detected by the force sensor comes entirely from the honing feed direction, providing accurate force feedback data for closed-loop control.

[0028] Combination Figure 7 As shown, the machine tool base assembly 5 includes a mounting plate 5-1, a module mounting plate 5-2, and a profile frame 5-3. The mounting plate 5-1 and the module mounting plate 5-2 are respectively mounted on the top of the profile frame 5-3 by screws, providing a stable mounting platform for other components.

[0029] Combination Figure 8As shown, the cooling system 6 includes a bamboo-joint tube 6-1, a first ball valve 6-2, a cooling oil fixing seat 6-3, a straight connector 6-4, a first hydraulic hose 6-5, a tee connector 6-6, an oil receiving tank assembly 6-7, a second hydraulic hose 6-8, a third hydraulic hose 6-9, a second ball valve 6-10, a cooling oil pump 6-11, a filter assembly 6-12, and a cooling oil tank 6-13. The bamboo-joint tube 6-1 is threaded onto the first ball valve 6-2, and the first ball valve 6-2 is threaded onto... On the cooling oil mounting base 6-3, a straight connector 6-4, a first hydraulic hose 6-5, and a tee connector 6-6 are sequentially connected by threads. The straight connector 6-4 connects to the cooling oil mounting base 6-3, and the other two ends of the tee connector 6-6 connect to the second hydraulic hose 6-8 and the third hydraulic hose 6-9, respectively. The second hydraulic hose 6-8 connects to the outlet of the cooling oil pump 6-11, and the third hydraulic hose 6-9 is connected to the cooling oil tank 6-13 after a second ball valve 6-10 is installed on it, forming an overflow circuit. The cooling oil pump 6-11 and the filter assembly 6-12 are both mounted on the cooling oil tank 6-13 with screws. The oil receiving trough assembly 6-7 is inserted into the filter assembly 6-12 to collect the cooling oil dripping from the processing area and filter it before returning it to the oil tank. The oil receiving trough assembly 6-7, the cooling oil mounting base 6-3, and the cooling oil tank 6-13 are all fixed to the machine tool base assembly 5 with screws. The cooling system 6 can control the start and stop of the cooling oil pump 6-11 via the M code of the CNC system. The ball valve is used to adjust the flow rate of the coolant. Excess cooling oil is returned to the cooling oil tank 6-13 through the overflow circuit.

[0030] Combination Figure 9As shown, the honing spindle assembly 7 includes a tightening nut 7-1, a honing sleeve 7-2, a hexagonal thin nut 7-3, a large nut 7-4, a transition sleeve 7-5, a tapered mandrel 7-6, a locating pin 7-7, a transmission sleeve 7-8, a limiting screw 7-9, and a push rod 7-10. The push rod 7-10 is installed in the center hole of the transmission sleeve 7-8 with a clearance fit. The push rod 7-10 is fixedly connected to the power spindle assembly 3-9. One end of the push rod 7-10 passes through the hollow stepped shaft 3-9-2 and then through the center hole on the first impact block 2-2, rotatably connecting with the first impact block 2-2. The limiting screw 7-9 is installed in the threaded holes on both sides of the transmission sleeve 7-8. The head of the limiting screw 7-9 extends into the straight grooves on both sides of the push rod 7-10, allowing the push rod 7-10 to slide only axially and not... It can rotate circumferentially; the locating pin 7-7 is installed on the front end face of the transmission sleeve 7-8 by interference fit, the rear end of the tapered mandrel 7-6 is connected to the front end of the push rod 7-10 by thread, and the locating outer circle of the tapered mandrel 7-6 is matched with the locating hole at the front end of the push rod 7-10 to ensure the coaxiality of the two; the transition sleeve 7-5 passes through the tapered mandrel 7-6 and is installed at the front end of the transmission sleeve 7-8 with clearance, and the two notches at the rear end of the transition sleeve 7-5 are matched with the locating pin 7-7 with clearance to achieve circumferential positioning. The large nut 7-4 connects the transition sleeve 7-5 to the transmission sleeve 7-8 via its internal thread. However, the transition sleeve 7-5 is not completely clamped, leaving an axial clearance of approximately 0.05mm, allowing it to float. The honing sleeve 7-2 is installed at the front end of the transition sleeve 7-5 by tightening the nut 7-1 and the hexagonal thin nut 7-3. The hexagonal thin nut 7-3 is used for reverse locking, ensuring that a certain floating clearance is also maintained between the honing sleeve 7-2 and the transition sleeve 7-5. The honing sleeve 7-2 has a circumferentially non-grooved collet structure, similar to an elastic collet. Under the conical tension of the tapered mandrel 7-6, it can achieve radial uniform expansion. When the tapered mandrel 7-6 retracts, the honing sleeve 7-2 returns to its free state due to its own elasticity.

[0031] The pneumatic impact system 2 pushes the push rod 7-10 of the honing spindle assembly 7 forward or backward. When impacting forward, the push rod 7-10 moves forward, the tapered mandrel 7-6 moves forward with it, the honing sleeve 7-2 expands, and the values ​​of the torque sensor and force sensor both increase. When impacting backward, the push rod 7-10 moves backward, the tapered mandrel 7-6 moves backward, the honing sleeve 7-2 contracts, and the values ​​of torque and force both decrease. When the proportional valve air pressure is adjusted to a large value and the impact is continued backward, the push rod 7-10 can be completely disengaged from the honing sleeve 7-2, the impact bracket 2-1 is limited by the limiting block 2-8, and the workpiece can be removed after the honing sleeve 7-2 retracts freely.

[0032] The honing spindle assembly 7 adopts a double floating design: the honing sleeve 7-2 floats relative to the transition sleeve 7-5, and the transition sleeve 7-5 floats relative to the transmission sleeve 7-8. When the push rod 7-10 drives the tapered mandrel 7-6 forward, both the honing sleeve 7-2 and the transition sleeve 7-5 automatically align and contact with the tapered mandrel 7-6 under the action of the tapered surface, thus ensuring the coaxiality of the honing sleeve 7-2, the tapered mandrel 7-6, and the push rod 7-10; at the same time, the transmission sleeve 7-8 is coaxially installed with the power spindle assembly 3-9, thus ultimately ensuring that the runout of the honing sleeve 7-2 relative to the spindle is controlled within 0.04mm. This extremely small runout is the key to ensuring the quality of honing.

[0033] Combination Figure 10 As shown, the workpiece fixture 8 is a floating fixture, including a knurled high-head screw 8-1, an adjusting pin 8-2, a fixture body 8-3, an outer ring 8-4, a needle valve body fixing fixture 8-5, and a locating pin 8-6. The locating pin 8-6 is installed on the inner wall of the outer ring 8-4 with an interference fit. The adjusting pin 8-2 passes through corresponding holes on the fixture body 8-3 and the outer ring 8-4 with a clearance fit, allowing for fine-tuning of the position. The knurled high-head screw 8-1 is threaded onto the fixture body 8-3, and its end presses against the plane of the adjusting pin 8-2 for fixation. The outer wall of the needle valve body fixing fixture 8-5 has a spiral groove. During installation, the spiral groove is aligned with the locating pin 8-6, inserted, and rotated to complete the clamping. Figure 11 As shown, the needle valve body fixing fixture 8-5 includes a fixture body 8-5-1, a positioning pin 8-5-2, a needle valve body 8-5-3, and a pressure cap 8-5-4. The positioning pin 8-5-2 is interference-fitted onto the inner wall of the fixture body 8-5-1. The needle valve body 8-5-3 is inserted into the fixture body 8-5-1 with a gap. Rotation causes the positioning pin 8-5-2 to engage in the positioning groove of the needle valve body. The bottom plane of the needle valve body is flush with the inner end face of the fixture body 8-5-1. Then, the pressure cap 8-5-4 is screwed into the fixture body 8-5-1 through threads to press the needle valve body 8-5-3 and achieve fixation.

[0034] The core function of the workpiece fixture 8 is to ensure that the workpiece maintains a certain amount of floating in all six degrees of freedom. When clamping, the inner hole of the workpiece is inserted into the honing sleeve 7-2 by a small section to achieve automatic centering, ensuring that the inner hole of the workpiece and the honing spindle assembly 7 remain coaxial during the machining process, and avoiding the form and position errors caused by forced clamping.

[0035] The control system 9 includes a CNC system and a host computer. The CNC system is responsible for the precise reciprocating motion control of the servo feed system 4, the spindle speed control of the power system 3, the striking action control of the pneumatic striking system 2, and the start / stop control of the cooling system 6. The host computer is responsible for real-time acquisition of the torque value of the torque sensor assembly 3-3, the feed force value of the force sensor, and the coordinate position value of the CNC system, and performs real-time calculations and analysis.

[0036] The CNC automatic feed honing machine of the present invention has two processing modes: manual and automatic.

[0037] The working process in manual processing mode is as follows: The CNC system controls the servo feed system 4 to stop in the standby position, and the oil baffle 1-4 retracts. The needle valve body is manually inserted into the needle valve body fixing fixture 8-5. Then, the center hole of the needle valve body fixing fixture 8-5, containing the workpiece, is aligned with the honing sleeve 7-2. After inserting a short section, it is rotated to make the spiral groove lock the positioning pin 8-6, completing the workpiece clamping. The oil baffle 1-4 extends, the machine tool is started, and the tapered spindle (7-6) of the honing spindle assembly 7 begins to rotate. The servo feed system 4 drives the workpiece to perform reciprocating linear motion. The CNC system matches the spindle speed with the feed rate. The speed of the honing process creates a regular cross-hatching pattern on the inner surface of the hole. The operator sets the proportional valve pressure in the host computer and manually controls the number of cylinder strikes using the forward impact button on the control cabinet. Simultaneously, the operator observes the torsional shear stress τ and axial circumferential pressure P displayed on the host computer. Striking stops once the target values ​​are reached. Honing continues until the set number of reciprocating strikes is reached, at which point the machining process ends, power system 3 stops, and the servo system returns to standby. The operator presses the backward impact button to disengage the tapered mandrel from the honing sleeve, allowing the workpiece to be removed. The manual mode is primarily used for system data acquisition. By manually honing, empirical values ​​of torsional shear stress and axial circumferential pressure for workpieces of different specifications are accumulated, establishing a parameter database to provide calibration data for the automatic machining mode.

[0038] The automatic processing mode works as follows: The CNC system controls the servo feed system 4 to stop in the standby position, and the oil baffle 1-4 retracts; the workpiece is manually clamped, and the clamping method is the same as in manual mode; the oil baffle 1-4 extends, the machine tool is started, the spindle rotates, and the servo feed system 4 drives the workpiece to reciprocate; at the same time, the host computer sends the preset parameters to the CNC system, first adjusting the proportional valve pressure to the set value, and the CNC system controls the pneumatic striking system 2 to automatically strike the push rod 7-10, adjusting the torsional shear stress τ and the axial circumferential pressure P to the preset target range, forming a gap between the honing sleeve 7-2 and the tapered mandrel 7-6. The self-locking mechanism uses a Morse taper; after reaching the target value, it enters the normal honing stage, with the taper mandrel (7-6) rotating continuously and the workpiece reciprocating continuously; during the processing, the host computer monitors the line graphs of torsional shear stress τ and axial circumferential pressure P in real time. When the peak-to-trough difference of τ and the peak-to-trough difference of P both shrink to their respective set threshold ranges, the workpiece is deemed to be qualified; after qualification, the processing ends automatically, the power system 3 stops, the servo feed system 4 returns to the standby position, and the pneumatic striking system 2 strikes backward to retract the honing sleeve 7-2, allowing the workpiece to be removed.

[0039] The control method for the CNC automatic feed honing machine of the present invention specifically includes the following steps: S1. Parameter acquisition: The torque value T during the honing process is acquired in real time through the torque sensor assembly 3-3, the axial feed forces F1 and F2 on both sides are acquired in real time through the force sensor 4-4, and the coordinate values ​​of the CNC system are acquired in real time through the host computer to obtain the axial length L of the honing sleeve 7-2 in the workpiece. S2. Contact Area Calculation: Based on the radius r and axial length L of the honing sleeve 7-2, calculate the real-time contact area S = πr between the honing sleeve 7-2 and the inner hole of the workpiece. 2 L; S3. Stress parameter calculation: Based on the collected torque value T and contact area S, calculate the torsional shear stress τ=T / S; based on the collected axial feed forces F1 and F2 and contact area S, calculate the axial circumferential pressure P=(F1+F2) / S. S4. Automatic feed adjustment: The real-time calculated torsional shear stress τ and axial circumferential pressure P are compared with the preset target values. The control system 9 controls the pneumatic striking system 2 to strike the push rod 7-10 forward or backward, and adjusts the diameter of the honing sleeve 7-2 so that the torsional shear stress τ and axial circumferential pressure P are maintained within the set range. S5. Automatic qualification judgment: During the honing process, the fluctuation of torsional shear stress τ and axial circumferential pressure P with the honing reciprocating motion is monitored in real time. When the difference between the peak and valley of torsional shear stress τ and the difference between the peak and valley of axial circumferential pressure P are both less than their respective set thresholds, the workpiece is judged to be qualified for honing. S6. Processing complete: After passing the inspection, the control system 9 controls the pneumatic striking system 2 to strike backward, causing the honing sleeve 7-2 to retract. The servo feed system 4 returns to the standby position, the power system 3 stops rotating, and the processing is complete.

[0040] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0041] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A CNC automatic feed honing machine, characterized in that: The machine tool includes a machine tool base assembly, a protective cover assembly, a pneumatic hammering system, a power system, a servo feed system, a cooling system, a honing spindle assembly, a workpiece fixture, and a control system, all of which are mounted on the machine tool base assembly. The honing spindle assembly is mounted on the power system, and the workpiece fixture is mounted on the servo feed system; the pneumatic striking system, the power system, and the honing spindle assembly are arranged coaxially; the honing spindle assembly includes a honing sleeve, a tapered mandrel, and a push rod, the tapered mandrel is connected to the push rod, and the honing sleeve is fitted over the outside of the tapered mandrel; The pneumatic striking system includes a cylinder and a proportional valve. The proportional valve is used to control the air pressure entering the cylinder. The cylinder is used to strike the push rod forward or backward to drive the tapered mandrel to move axially and control the change in the diameter of the honing sleeve. The power system includes a torque sensor assembly, which is used to collect the torque value T during the honing process in real time. The servo feed system includes a force sensor, which is used to collect the axial feed force during the honing process in real time. The control system includes a CNC system and a host computer. The CNC system is used to control the reciprocating motion of the servo feed system, the rotational motion of the power system, and the striking action of the pneumatic striking system. The host computer is used to collect the torque value T, axial feed force, and coordinate values ​​of the CNC system in real time and automatically determine whether the honing process is qualified.

2. The CNC automatic feed honing machine according to claim 1, characterized in that: The pneumatic striking system further includes an impact bracket, a first impact block, a cylinder impact head, a linear guide rail, a cylinder base, a second impact block, and a limiting block; the cylinder impact head is connected to the output end of the cylinder, and the cylinder is mounted on the machine tool base assembly via the cylinder base; the first impact block and the second impact block are respectively mounted on both sides of the impact bracket, and the first impact block has a central hole for the push rod to pass through; the limiting block is used to limit the extreme position of the push rod's backward movement.

3. A CNC automatic feed honing machine according to claim 1, characterized in that: The power system also includes a motor, coupling, small synchronous pulley, synchronous belt, shim block, driven shaft, bearing housing, and power spindle assembly; the motor is connected to the input end of the torque sensor assembly via the coupling, and the small synchronous pulley is installed at the output end of the torque sensor assembly; the driven shaft is installed in the bearing housing, and one end of the driven shaft is connected to the small synchronous pulley; the small synchronous pulley is connected to the power spindle assembly via the synchronous belt; the driven shaft and the bearing housing form a driven support structure to eliminate the influence of the lateral force of the synchronous belt on the measurement accuracy of the torque sensor assembly.

4. A CNC automatic feed honing machine according to claim 3, characterized in that: The power spindle assembly includes a lubricating oil connector, a hollow stepped shaft, a one-way thrust ball bearing, a ball bearing, a spindle housing, a spindle base, a transition sleeve, a bearing lock nut, and a timing pulley. The lubricating oil connector is threaded onto the spindle housing, which is connected to the spindle base. The hollow stepped shaft is supported within the spindle housing by one-way thrust ball bearings and ball bearings arranged at both ends. The transition sleeve is installed at the end of the hollow stepped shaft for connecting to the honing spindle assembly. The bearing lock nut is installed on the hollow stepped shaft and presses the bearing. The timing pulley is installed on the hollow stepped shaft.

5. A CNC automatic feed honing machine according to claim 1, characterized in that: The servo feed system further includes a motion module, a module connecting plate, a connecting block, a slider bracket, a linear guide rail, and a connecting plate; the motion module includes a main module and a sub-module, and the main module and the sub-module maintain synchronous movement; one end of the connecting block is connected to the module connecting plate, and the other end of the connecting block is connected to one end of a force sensor; the other end of the force sensor is connected to the slider bracket; the slider bracket is mounted on the linear guide rail, and the linear guide rail is mounted on the module connecting plate; the connecting plate connects the two slider brackets, and the workpiece fixture is mounted on the connecting plate.

6. A CNC automatic feed honing machine according to claim 1, characterized in that: The honing spindle assembly also includes a transmission sleeve, a limiting screw, a locating pin, a transition sleeve, a large nut, a tightening nut, and a hexagonal thin nut. The push rod clearance is installed inside the transmission sleeve, and the limiting screw is installed on the side wall of the transmission sleeve and extends into the straight groove of the push rod. The transition sleeve clearance is installed at the end of the transmission sleeve, and the large nut connects the transition sleeve to the transmission sleeve and retains axial floating clearance. The honing sleeve is installed on the transition sleeve by the tightening nut and the hexagonal thin nut and remains in a floating state. The honing sleeve is a collet structure without circumferential slots, which achieves radial expansion under the tension of the tapered mandrel, and the tapered mandrel returns to its original shape by its own elasticity when it retracts.

7. A CNC automatic feed honing machine according to claim 1, characterized in that: The cooling system comprises a bamboo-joint tube, a first ball valve, a cooling oil fixing seat, a straight connector, a first hydraulic hose, a tee connector, an oil receiving groove assembly, a second hydraulic hose, a third hydraulic hose, a second ball valve, a cooling oil pump, a filter assembly, and a cooling oil tank. The bamboo-joint tube is mounted on the first ball valve, which is mounted on the cooling oil fixing seat. The straight connector, the first hydraulic hose, and the tee connector are connected sequentially. The straight connector is connected to the cooling oil fixing seat, and the other two ends of the tee connector are connected to the second and third hydraulic hoses. The second hydraulic hose is connected to the cooling oil pump, and the second ball valve is mounted on the third hydraulic hose. The second ball valve is mounted on the cooling oil tank. The cooling oil pump is mounted on the cooling oil tank, and the filter assembly is mounted on the cooling oil tank. The oil receiving groove assembly is connected to the interior of the filter assembly. The oil receiving groove assembly, the cooling oil fixing seat, and the cooling oil tank are mounted on the machine tool base assembly.

8. A control method for a CNC automatic feed honing machine, characterized in that: The CNC automatic feed honing machine according to any one of claims 1-7 includes the following steps: S1. Parameter acquisition: The torque value T during the honing process is acquired in real time through the torque sensor assembly, the axial feed forces F1 and F2 on both sides are acquired in real time through the force sensor, and the coordinate values ​​of the CNC system are acquired in real time through the host computer to obtain the axial length L of the honing sleeve in the workpiece. S2. Contact Area Calculation: Based on the radius r and axial length L of the honing sleeve, calculate the real-time contact area S between the honing sleeve and the workpiece's inner hole: S = πr 2 L; S3. Stress parameter calculation: Based on the collected torque value T and contact area S, calculate the torsional shear stress τ=T / S; based on the collected axial feed forces F1 and F2 and contact area S, calculate the axial circumferential pressure P=(F1+F2) / S. S4. Automatic feed adjustment: The real-time calculated torsional shear stress τ and axial circumferential pressure P are compared with the preset target values. The control system controls the pneumatic striking system to strike the push rod forward or backward, adjusting the diameter of the honing sleeve so that the torsional shear stress τ and axial circumferential pressure P are maintained within the set range. S5. Automatic qualification judgment: During the honing process, the fluctuation of torsional shear stress τ and axial circumferential pressure P with the honing reciprocating motion is monitored in real time. When the difference between the peak and valley of torsional shear stress τ and the difference between the peak and valley of axial circumferential pressure P are both less than their respective set thresholds, the workpiece is judged to be qualified for honing. S6. Processing complete: After passing the inspection, the control system controls the pneumatic striking system to strike backward to retract the honing sleeve, the servo feed system returns to the standby position, the power system stops rotating, and the processing is complete.

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