CN108747585B - Machine tool spindle clamping force on-line monitoring system - Google Patents

Abstract

The invention discloses an online monitoring system for clamping force of a machine tool spindle, which comprises a spindle shell, wherein a pull rod is arranged in the spindle shell, and the online monitoring system is characterized in that: the utility model provides a be located the outside pull rod end of main shaft shell and be provided with a set of displacement and reduce the mechanism, displacement reduce the mechanism and include primary driven lever, secondary driven lever and be located a plurality of bracing pieces on primary driven lever and the secondary driven lever respectively, primary driven lever head end is fixed in pull rod tip side, and the end is connected secondary driven lever through the bracing piece, the end of secondary driven lever passes through the bracing piece setting on the up end of main shaft shell, be provided with a flexure strip between the front end of secondary driven lever and the up end of main shaft shell, one side of flexure strip is pasted and is fixed with piezoceramics film, and the opposite side is pasted and is fixed with giant magnetostrictive thin piece. The invention can ensure that the real-time recovery elasticity of the disc-shaped elastic sheet in the main shaft of the machine tool is monitored in the whole process in the working process of the machine tool, and the reliability of the main shaft clamping tool handle is improved.

Description

Online monitoring system for machine tool spindle clamping force

[Technical field]

The invention relates to the technical field of machine tools, and in particular to an online monitoring system for the clamping force of a machine tool spindle.

【Background technique】

There are generally two ways to clamp the spindle of a vertical machining center, one is thrust clamping and the other is tension clamping. Both clamping methods use the sliding fit of the wedge surface to achieve clamping. The spindle structure of tension clamping is relatively simple, which helps to stabilize the spindle assembly accuracy and ensure machining performance.

The tension clamping spindle has a pull rod inside, on which dozens of disc-shaped springs are arranged, relying on the recovery elastic force of the disc-shaped springs as the lifting and clamping force of the tool handle. For a machine tool spindle with this structure, the recovery elastic force of the disc-shaped springs tends to decrease during continuous use. Once the recovery elastic force of the disc-shaped springs drops to a certain value, the spindle will fail to clamp the tool handle, posing a hidden danger of processing accidents and causing a decrease in processing accuracy.

[Summary of the invention]

The purpose of the present invention is to solve the problems in the prior art and to propose an online monitoring system for the clamping force of a machine tool spindle, which can monitor the real-time recovery force of the disc-shaped spring in the spindle of the machine tool during operation, thereby improving the reliability of the spindle clamping tool holder.

To achieve the above-mentioned purpose, the present invention proposes an online monitoring system for the clamping force of a machine tool spindle, comprising a spindle housing, a pull rod is arranged in the spindle housing, a plurality of disc springs are mounted on the pull rod, the upper end of the pull rod passes through the spindle housing, and is fixedly connected to the output shaft of the knife cylinder through a connecting sleeve, and is characterized in that: a group of displacement reduction mechanisms are arranged at the pull rod end located outside the spindle housing, the displacement reduction mechanism comprises a primary driven rod, a secondary driven rod and a plurality of support rods respectively located on the primary driven rod and the secondary driven rod, the head end of the primary driven rod is fixed to the side of the pull rod end, the end is connected to the secondary driven rod through the support rod, the end of the secondary driven rod is arranged on the upper end surface of the spindle housing through the support rod, and the front end of the secondary driven rod A bending sheet is arranged between the upper end surface of the spindle housing, a piezoelectric ceramic film is pasted and fixed on one side of the bending sheet, and a giant magnetostrictive sheet is pasted and fixed on the other side. An eddy current coil with multiple turns is mounted on the combination of the bending sheet, the piezoelectric ceramic film and the giant magnetostrictive sheet; both ends of the wire of the eddy current coil are connected to a signal amplifier, and the signal amplifier is connected to the input end of the current stabilizer, the first filter and the controller in sequence; electrode wires are respectively led out from the two side surfaces of the piezoelectric ceramic film, and the electrode wires are connected to the input end of the transformer, the voltage stabilizer, the second filter and the controller in sequence; the output end of the controller is connected to the solenoid valve through a wire, and the solenoid valve is respectively connected to the air pump and the knife cylinder through an air guide tube.

Preferably, the knife-beating cylinder is fixed to the upper end of the spindle housing through a support frame.

Preferably, the connection points between the primary driven rod, the secondary driven rod and the support rod of the displacement reduction mechanism are all flexible hinge structures.

Preferably, the controller is a PMC controller of a FANUC system.

Preferably, the piezoelectric ceramic film and the giant magnetostrictive film are both adhered to the bending sheet by using epoxy resin.

Beneficial effects of the present invention: The present invention monitors the elastic force of the disc spring on the pull rod in real time by setting a detection module associated with the movement of the spindle pull rod at the upper end of the spindle housing. On the basis of this main idea, a combination of piezoelectric ceramic film and giant magnetostrictive film is creatively adopted for detection. The two groups of collected signals based on different principles can corroborate each other, preventing malicious misjudgment of the normal operation of the spindle due to significant errors, thereby ensuring the reliability of the spindle operation.

The features and advantages of the present invention will be described in detail through embodiments in conjunction with the accompanying drawings.

【Brief Description of the Drawings】

Fig. 1 is a schematic diagram of the structure of the present invention;

FIG. 2 is an enlarged view of portion A in FIG. 1 .

In the figure: 1-spindle housing, 2-disc spring, 3-pull rod, 4-knife cylinder, 5-support frame, 6-signal amplifier, 7-transformer, 8-current stabilizer, 9-voltage stabilizer, 10-first filter, 11-second filter, 12-controller, 13-solenoid valve, 14-air pump, 15-primary driven rod, 16-secondary driven rod, 17-bending sheet, 18-piezoelectric ceramic film, 19-giant magnetostrictive sheet, 20-eddy current coil.

【Detailed ways】

Referring to Figures 1 and 2, the present invention is an online monitoring system for the clamping force of a machine tool spindle, comprising a spindle housing 1, a pull rod 3 is arranged inside the spindle housing 1, a plurality of disc springs 2 are mounted on the pull rod 3, the upper end of the pull rod 3 passes through the spindle housing 1, and is fixedly connected to the output shaft of a knife cylinder 4 through a connecting sleeve, and is characterized in that: a group of displacement reduction mechanisms are arranged at the end of the pull rod 3 located outside the spindle housing 1, the displacement reduction mechanism comprises a primary driven rod 15, a secondary driven rod 16 and a plurality of support rods respectively located on the primary driven rod 15 and the secondary driven rod 16, the head end of the primary driven rod 15 is fixed to the side of the end of the pull rod 3, the end of the secondary driven rod 16 is connected to the secondary driven rod 16 through the support rod, the end of the secondary driven rod 16 is arranged on the upper end surface of the spindle housing 1 through the support rod, and the front end of the secondary driven rod 16 is connected to the upper end of the spindle housing 1 A bending sheet 17 is arranged between the surfaces, a piezoelectric ceramic film 18 is pasted and fixed on one side of the bending sheet 17, and a giant magnetostrictive film 19 is pasted and fixed on the other side. An eddy current coil 20 with multiple turns is mounted on the combination of the bending sheet 17, the piezoelectric ceramic film 18 and the giant magnetostrictive film 19; the two ends of the wire of the eddy current coil 20 are connected to a signal amplifier 6, and the signal amplifier 6 is connected to the input end of the current stabilizer 8, the first filter 10 and the controller 12 in sequence. Electrode wires are respectively drawn out from the two sides of the piezoelectric ceramic film 18, and the electrode wires are connected to the input end of the transformer 7, the voltage stabilizer 9, the second filter 11 and the controller 12 in sequence. The output end of the controller 12 is connected to the electromagnetic valve 13 through a wire, and the electromagnetic valve 13 is respectively connected to the air pump 14 and the knife-beating cylinder 4 through an air guide tube. The knife-beating cylinder 4 is fixed to the upper end of the spindle housing 1 through a support frame 5. The connection between the primary driven rod 15 and the secondary driven rod 16 of the displacement reduction mechanism and the support rod is a flexible hinge structure. The controller 12 is a PMC controller of a FANUC system. The piezoelectric ceramic film 18 and the giant magnetostrictive film 19 are both adhered to the bending sheet 17 with epoxy resin.

Working process of the present invention:

In the working process of the online monitoring system for the clamping force of the main axis of a machine tool of the present invention, the controller 12 passes a high potential to the electromagnetic valve 13, the electromagnetic valve 13 is turned on, and the high-pressure gas in the air pump 14 enters the return chamber of the knife-beating cylinder 4, so that the output shaft of the knife-beating cylinder 4 contracts, and then the pull rod 3 moves up. The upward movement of the pull rod 3 generates pressure on the disc spring 2 and compresses it. Due to the upward movement of the pull rod 3, the end of the primary driven rod 15 is pressed down, and then the end of the secondary driven rod 16 is pressed down, generating bending pressure on the bending piece 17; the piezoelectric ceramic film 18 generates an electric charge under pressure. If the knife-beating cylinder 4 continuously switches the extension and contraction state of the output shaft, the pressure A continuous voltage can be generated at the electric ceramic film 18. At the same time, the giant magnetostrictive sheet 19 is subjected to constantly switched stretching and compression, and the magnetic field change will cause a continuous current to be generated in the eddy current coil 20. The two electrical signals pass through their respective processing circuits and enter the controller 12 for verification and comparison. The judgment is made by setting a difference threshold in the controller 12. If the deviation of the calculated pressure values of the two is less than the set threshold, the judgment signal is valid, and the effectiveness of the elastic force of the disc spring 2 is judged based on the valid signal to achieve online monitoring. If the disc spring 2 is judged to be invalid, the controller 12 resets the solenoid valve 13 to block the further operation of the knife cylinder 4.

The above embodiments are intended to illustrate the present invention, not to limit the present invention. Any solution that is a simple transformation of the present invention belongs to the protection scope of the present invention.

Claims (3)

1. The utility model provides a lathe main shaft clamping force on-line monitoring system, includes the main shaft shell, be provided with the pull rod in the main shaft shell, the cover is equipped with multi-disc dish reed on the pull rod, and the pull rod upper end passes the main shaft shell to through the output shaft fixed connection of connecting sleeve and tool driving jar, its characterized in that: the tie rod end outside the main shaft shell is provided with a group of displacement reduction mechanism, the displacement reduction mechanism comprises a primary driven rod, a secondary driven rod and a plurality of support rods respectively positioned on the primary driven rod and the secondary driven rod, the head end of the primary driven rod is fixed on the side surface of the end part of the tie rod, the tail end of the primary driven rod is connected with the secondary driven rod through the support rods, the tail end of the secondary driven rod is arranged on the upper end surface of the main shaft shell through the support rods, a bending piece is arranged between the front end of the secondary driven rod and the upper end face of the main shaft shell, one side of the bending piece is fixedly stuck with a piezoelectric ceramic film, the other side of the bending piece is fixedly stuck with a giant magnetostrictive film, and an eddy current coil with multiple turns is sleeved on the combination of the bending piece, the piezoelectric ceramic film and the giant magnetostrictive film; the two ends of a lead of the eddy current coil are connected to a signal amplifier, the signal amplifier is sequentially connected with a current stabilizer, a first filter and the input end of a controller, electrode wires are respectively led out from two side surfaces of the piezoelectric ceramic film, the electrode wires are sequentially connected with a transformer, the voltage stabilizer, a second filter and the input end of the controller, the output end of the controller is connected with an electromagnetic valve through a lead, and the electromagnetic valve is respectively connected with an air pump and a knife cylinder through an air duct; the tool beating cylinder is fixed at the upper end of the main shaft shell through a support frame; the joints of the primary driven rod, the secondary driven rod and the supporting rod of the displacement shrinking mechanism are flexible hinge structures.

2. The machine tool spindle clamping force on-line monitoring system of claim 1, wherein: the controller is a PMC controller of the FANUC system.

3. The machine tool spindle clamping force on-line monitoring system of claim 1, wherein: the piezoelectric ceramic film and the giant magnetostrictive thin sheet are adhered to the bending sheet by adopting epoxy resin.