JPS63300862A - Grinding spindle - Google Patents

Abstract

PURPOSE:To permit the free high speed revolution and permit the replacement of tools by installing the captioned spindle onto the spindle of a machine tool and allowing the output shaft of an air motor in a casing to permit the mounting of a grinding tool. CONSTITUTION:The captioned spindle is equipped with a holder 6 installed in demountable ways onto a machine tool spindle shaft 11, casing 2 fixed onto the holder 6, air motor 3 fixed in the casing 2, and the output shaft 8 of the air motor 3 supported in rotatable ways onto the casing 2 by the bearings 9 and 10, and a grinding tool is installed on the output shaft 8. Therefore, the holder 6 has the same shape to the tool, and tools can be easily replaced in the machine tool. Further, the air motor 3 can be removed at high speed independently of the revolution of the spindle of the machine tool, and in case of a common tool, working can be carried out by the main spindle 11 as in the common case.

Description

DETAILED DESCRIPTION OF THE INVENTION Constriction light... The present invention relates to a grinding spindle that can be attached to a machine tool, specifically a machining center.

[Advanced] When finishing the groove of a cylindrical cam by using a machine such as a machining center, the rotation speed of the main shaft must be extremely high. For example, use a Borazon grindstone. Then, when the cutting speed is 2000 m/+*in and the diameter of the grindstone is 201, a rotation of about 32000 rpm is required.

One way to rotate a grinding wheel or grinding tool at such high speeds is to use a machining center with a high-speed spindle, but in this case, a machining center dedicated to high-speed rotation is used, and it is difficult to perform heavy cutting at low speeds. If you want to do this, there is a problem that the main shaft bearing is too weak to use.

There is also a method of using an attachment equipped with a mechanical speed increaser such as a gear or belt, but in this case, there are limits to the mechanical speed increaser, and in the case of a small diameter grinding wheel, lQOO
There was a problem that the rotational speed could not be increased beyond Orpm.

Furthermore, there is a method of using an attachment equipped with an electrical speed increaser such as a high-frequency motor, but in this case there are problems in that the device is expensive and the tool cannot be replaced by a machining center because it requires electrical wiring. be.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a grinding spindle that can freely rotate at a desired high speed and can be used in a machine tool, such as a machining center, in a state where it can be replaced with other tools. It is an object.

The present invention has achieved the above object by providing a holder that is removably attached to the main shaft of a machine tool, a casing that is fixed to the holder, a motor that is fixed within the casing, and a motor that is rotatably supported by the casing by a bearing. This was achieved by a grinding spindle characterized in that it has an output shaft of the air motor, and the output shaft is formed so that a grinding tool can be attached thereto.

The structure and operation of the present invention will be explained in detail based on the embodiment shown in the drawings.

1 to 4, the grinding spindle l includes a casing 2, an air motor 3 fixed in the casing 2, a presser member 4 that seals the air motor 3 to the casing 2, and the presser member 4. A holder 6 is fixed to the holder 6 by a bolt 5. The holding member 4 is fixed to the casing 2 with bolts 7.

The air motor 3 has an air motor casing 15 (for example, made of ceramic) fixed to the casing 2, and a rotor 16 rotatably supported by the air motor casing 15, and an output shaft 8 is fixed to the rotor 16. The output shaft 8
are the bearing 9 and the holding member 4 attached to the casing 2.
It is rotatably supported by a bearing 10 mounted on.

Vanes 17 made of ceramic, for example, are slidably attached to the rotor 16 .

The holder 6 can be removably attached to a main shaft 11 of a machine tool, for example, a machining center.

The holder 6 has a tapered surface portion 12 so that it can be accurately positioned and brought into close contact with the main shaft 11 of a machine tool, and the holder 6 is formed in the same manner as the tool holder or workpiece mounting pallet holder proposed by the applicant.

The output shaft 8 of the air motor 3 is formed similarly to a spindle shaft on which a tool of a machine tool is attached, and a grinding tool 13 or another tool can be fixed thereto.

A flow path 14 for compressed air for driving the rotor of the air motor 3 is formed in the holding member 4, and the flow path 14 is connected to a compressed air source via a flow path 10 provided in a coupler 18.

A lubrication path 20.21 is formed in the casing 2 and the holding member 4 to supply lubricating oil to the bearing 9.10.
The lubrication passages 20 and 21 are connected by an intermediate passage 22 formed in the air motor casing 15. The lubricating passage 21 of the holding member 4 is connected to a lubricating oil source via a flow passage 23 formed in the coupler 19. As the lubricating oil, a mixture of oil and air can be used.

The overflowing lubricating oil after lubrication of the bearings is returned to the tank through return channels 24,25.

A portion of the lubricating oil flowing from the tip of the casing 2 can also be used for cooling the grindstone 13 along the output shaft 8.

When using the above grinding spindle, the main shaft 11 of the machine tool does not rotate, and compressed air is supplied from the flow path 23 to rotate the rotor 16 of the air motor 3 at high speed. After rotating the rotor 16, the air passes through a space 26 formed in the air motor casing 15 and is discharged from a discharge passage 27. The output shaft 8 is rotated at a desired high speed by the drive of the air motor 3,
The grinding tool 13 performs desired grinding.

By removing the grinding spindle 1, attaching an ordinary tool to the main spindle 11, and driving the main spindle 11, low-speed machining can be performed as desired.

The operation of the grinding spindle l is effected, for example, by a control circuit shown in FIG.

The flow rate supplied to the air motor 3 in accordance with the rotational speed of the output shaft 8 and the input voltage of the proportional valve controller corresponding to the flow rate are set in advance in the controller.

Since the rotation speed of the output shaft under no load is proportional to the flow rate of the air motor 3, if the relationship between the rotation speed and the flow rate is set at one point, the other rotation speeds can be calculated.

A rotation speed instruction signal is input to the controller from an NC device of a machine tool, for example, a machining center.

When the controller starts driving, a signal is sent to the solenoid valve, which turns on the solenoid valve and opens the pneumatic circuit.

Further, the controller outputs a voltage corresponding to the rotation speed determined according to the rotation instruction signal from the NC device to the proportional controller.

The electrical signal from the proportional valve controller adjusts the opening degree of the proportional valve as a flow rate adjustment valve, and the amount of compressed air supplied from the air source via the solenoid valve is adjusted, and the adjusted amount of air is supplied to the air motor. be done. that time,
The amount of air supplied to the air motor is constantly detected by a flow meter, and the data is fed back to the controller by electrical signals.

The data from the flowmeter and the flow rate stored in the controller are compared and calculated, and the proportional valve controller is controlled according to the difference, and the proportional valve is adjusted so that the flow rate supplied to the air motor corresponds to the specified rotation speed. The rotational speed of the air motor is kept constant by maintaining a constant flow rate.

If the rotation of the air motor decreases due to an increase in load or other reasons during grinding, the flow rate of air flowing to the air motor will decrease, so the flow meter detects the decrease in flow rate, and the controller controls the proportional valve to increase the air flow rate. Make it.

Furthermore, if the air motor stops due to an increase in load, the pressure in the air circuit increases. In order to solve this problem caused by overload, a pressure switch is connected to the air flow path, and a detection signal from the pressure switch is sent to the controller, which causes an emergency stop of operation when the pressure in the air flow path increases beyond a predetermined pressure. let

According to the present invention, the grinding spindle has a holder having the same shape as the tool, and can be easily replaced with the tool at the machining center. It is only necessary to add a coupler connection for supplying compressed air to the machining center, and it does not require a particularly complex structure and can be used with existing equipment.

Since the grinding spindle according to the present invention is equipped with an air motor, high-speed rotation can be obtained independently of the rotation of the main shaft of the machining center. Moreover, when using an ordinary tool, it can be processed using the main spindle as usual.

By installing a proportional valve in the air circuit of the air motor and controlling it with a controller, it is possible to eliminate fluctuations in rotation speed due to changes in load.

[Brief explanation of drawings]

FIG. 1 is a front cross-sectional view of a grinding spindle according to the present invention, taken along line 1--1 in FIG. 2, and FIG.
-H cross-sectional view, Figure 3 is taken along line III-II in Figure 2.
4 is a sectional view taken along line TV-rV in FIG. 3, and FIG. 5 is an air control circuit diagram of the air motor.

Claims (1)

[Claims] A grinding spindle that is attached to a machine tool includes a holder that is removably attached to the main shaft of the machine tool, a casing that is fixed to the holder, an air motor that is fixed within the casing, and an air motor that is rotatably supported by the casing by a bearing. A grinding spindle comprising: an output shaft of the air motor; the output shaft is formed to be able to attach a grinding tool.