JPH074762B2 - Table feeder - Google Patents

Description

The present invention relates to a table feeding device for reciprocating a table of a grinding machine, for example.

<< Prior art and its problems >> For example, a hydraulic cylinder is fixed to the lower surface of the table of the internal grinding machine, and the table is rapidly moved from the processing standby position to the processing position by driving the hydraulic cylinder (referred to as traverse motion). While the cylinder is held at this position, an eccentric cam mechanism provided at the other end of the reciprocating shaft protruding from the cylinder is rotationally driven to cause the grindstone to reciprocate (referred to as oscillation motion).

Further, the eccentric cam mechanism conventionally includes a slide ring fixed to the reciprocating shaft, an eccentric cam that slides in the front and rear in the moving direction, and a reciprocating shaft that drives the eccentric cam, inside the slide ring. The eccentric cam is eccentrically moved by rotationally driving the reciprocating shaft, and slidably contacts the inside of the slide ring to perform reciprocating motion according to the eccentric amount of the eccentric cam.

Further, the eccentric cam has a double ring shape, and the outer cam of the eccentric cam contacts the inner peripheral wall of the fried ring, thereby suppressing the component force in the lateral direction as much as possible and correcting it only along the axial direction of the reciprocating shaft. It is like this.

However, in the table feed device, since the hydraulic cylinder is used as the driving means for the traverse movement, it is difficult to cut at a low speed with respect to the work piece, which greatly limits the grinding work. .

Further, regarding the oscillation operation of the grinding wheel head table, when the oscillation operation is stopped, the eccentric position of the eccentric cam is not constant, and the table is not accurately positioned.

Therefore, for example, when trying to convert the oscillation stroke, it is necessary to return the eccentric cam to the reference position and then change the stroke, which is extremely time-consuming to adjust the eccentric stroke of the eccentric cam, and the work efficiency is significantly reduced. Is the reality.

As described above, it has been pointed out that the conventional table feeding device has a drawback that low-speed cutting is difficult and the table cannot be accurately positioned when the oscillation operation is stopped.

As a grindstone table feed device for low-speed cutting, a table in which a drive motor and a ball screw mechanism connected to the drive motor are attached to the traverse motion drive means has been proposed. I had the problem of not being able to do it.

Furthermore, in the conventional table feed device, when changing the eccentric stroke, the outer cam is set to the free state by loosening the adjustment screw with respect to the inner cam, and after rotating the outer cam at the desired angle, tighten the adjustment screw. The eccentric stroke was adjusted by.

In this way, there is a drawback that the work is complicated because it is done manually, and for example, in the oscillation operation of the table feed device, there is a mechanical acceleration limit (vibration limit), and if the eccentric stroke is set to a large value, On the other hand, the oscillation cycle, that is, the rotation speed of the eccentric cam is greatly limited. Therefore, in actual work, it is preferable to interlock the mutual relationship between the oscillation stroke and the oscillation cycle within the allowable range of the acceleration limit (vibration limit), but it is difficult to manually perform the stroke adjustment. The reality was that it made the work even more complicated.

<Purpose of the Invention> The present invention has been made in view of the above circumstances, and an object of the present invention is to enable both low-speed cutting and high-speed oscillation operation and to stop the oscillation operation. It is an object of the present invention to provide a table feeding device that can always position the table at an accurate position and can easily and reliably change the oscillation stroke to significantly improve the work efficiency.

<< Structure of the Invention >> In order to achieve the above object, the present invention converts the rotation of a motor for driving a table into a reciprocating motion of the table via a ball screw mechanism to move the table between a processing standby position and a processing position. A table feed device for performing a traverse motion at, converting the rotation of a reciprocating shaft drive motor into a reciprocating motion of a table through an eccentric cam, and performing an oscillation operation of the table at a table processing position, wherein the eccentric cam is A cam shaft eccentrically extended on the reciprocal axis, a cam plate rotatably supported by the cam shaft and having an outer periphery eccentric to the cam shaft, and a cam slidably contacting the outer periphery of the cam plate. A block, a slide ring for slidingly contacting the cam block and converting an eccentric rotational motion of the cam block into a reciprocating motion of the table, the cam shaft and a cam plate And a conversion mechanism for converting the rotation of the cam plate into the oscillation operation of the grindstone table via the cam block and the slide ring.The drive control means of the eccentric cam is for driving the reciprocating shaft. An encoder attached to the motor for reading a rotational position of the motor, an angle detector for detecting an eccentric angle which is an angle of a rotation direction of the cam plate with respect to the cam shaft in the eccentric cam, and the reciprocating shaft driving motor. And a control device for controlling the rotational drive of the eccentric cam according to a command from the control device in response to the output of the angle detector, and the clutch mechanism is operated to stop the eccentric cam at a constant angle. By connecting and disconnecting the cam shaft, the cam plate is rotated by a predetermined angle with respect to the cam shaft to adjust the eccentricity of the eccentric cam. Wherein the eccentricity is configured to vary the stroke of the oscillation operation by adjusting the.

<< Description of Embodiments >> Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment in which the present invention is applied to a table feeding device of a small internal grinding machine, FIG. 2 is a sectional view showing an eccentric cam mechanism which is a main part thereof, and FIG. 3 is the eccentric cam. FIG. 4 is an exploded perspective view showing the mechanism, and FIGS. 4 and 5 are a system block diagram and a flow chart diagram thereof for controlling the eccentric cam mechanism.

In the drawings, 1 is a table base, 2 is a grindstone table installed on the table base 1 so as to be slidable in the front-rear direction, a high frequency spindle motor 3 is fixed to the upper part of the table 2, and a grindstone at the tip thereof. The shaft 3a is opposed to a main spindle (not shown).

A servo motor 4 for driving the table is fixed to the lower surface of the table 2. A ball screw 6 having a lead of a predetermined angle is engraved on a rotary shaft 5 of the servo motor 4, and the ball screw 6 is fitted to a nut 7. The nut 7 which is fitted to the table base 1 side,
The rotation of the servomotor 4 causes the grindstone table 2 to perform a reciprocating motion called a traverse motion via the ball screw mechanism, thereby rapidly reciprocating the grindstone table 2 between the machining standby position and the machining position.

An encoder 8 is attached to the servo motor 4, and the encoder 8 reads the number of revolutions of the servo motor 4 to control the drive of the servo motor 4 in accordance with a command from a control device (not shown) so that the traverse motion is performed. It is accurate.

The nut 7 is held by a nut holder 7a, and the nut holder 7a is connected to an eccentric cam mechanism 10 described later via a connecting plate 9.

The eccentric cam mechanism 10 includes a reciprocating shaft 11 held on the table base 1 via a bearing 12, a servomotor 13 for driving the reciprocating shaft, and an encoder 14 for reading the rotation angle of the servomotor 13. 11 The upper end is connected to the eccentric cam mechanism 10, and the rotation of the servomotor 13 causes the connecting plate 9 to reciprocate through the eccentric cam mechanism 10, thereby causing the grinding head table 2 to reciprocate, that is, to perform oscillation operation. I am trying.

Next, the configuration of the eccentric cam mechanism 10 will be specifically described with reference to FIGS. 2 and 3.

First, a flange 11a is formed on the upper end of the reciprocating shaft 11, and a cam shaft 11b, which is eccentric by a predetermined amount, is integrally provided on the protruding end of the flange 11a.

A clutch plate 16 is interposed between the upper end of the cam shaft 11b and the cam plate 15 so that they can be connected and released freely.

On the other hand, the cam plate 15 is also configured to be freely connectable and releasable to the cam block 18 via the brake plate 17.

That is, the energization of the clutch 19 connects the cam shaft 11b and the cam plate 15 by the clutch plate 16, and when the energization of the clutch 19 is stopped, the connection between the cam shaft 11b and the cam plate 15 is released, and the cam plate 15 is a cam block by the brake plate 17
The torque of the clutch plate 19 is set to be larger than the torque of the brake plate 17 so as to connect with the brake plate 18.

Reference numeral 20 in the drawing denotes a slide ring reciprocally moved by the cam block 18, and this slide ring 20 transmits the reciprocating motion to the grindstone table 2 through the connecting plate 9.

The slide ring 20 has a rectangular shape, and guide rail portions 20a are formed on both sides of the slide ring 20.
Reciprocates in a straight line along the rollers provided in. In addition, a pair of cam floor blocks 21 and
2 is provided.

On the other hand, one bearing holding hole 18a is formed at the front end of the cam block 18, and two bearing holding holes 18a are formed at the rear end. The needle bearing 23 is inserted into the holding hole 18a, and the shaft 24 is inserted through the upper portion thereof. Then, by stopping the lower end with the E ring 25, the outer periphery of the needle bearing 23 is slightly rotatably held on the outer periphery of the cam block 18.

As a result, the outer peripheral portion of the needle bearing 23 comes into contact with the cam follower blocks 21 and 22 at three points.

Further, in FIGS. 2 and 3, a proximity switch 26 is provided on the lower surface side of the cam block 18, and a dock 27 is provided at a predetermined position of the cam plate 15 facing the proximity switch 26. The proximity switch 26 outputs a signal when the dock 27 is closest, that is, the proximity switch 26 detects one rotation of the cam plate 15.

Further, a stopper 28 is screwed and fixed to the tip of the cam shaft 11b, and is housed in a notched portion formed on the upper surface of the cam plate 15 in a fan shape of 90 degrees. This stopper 28 freely rotates within a range of 90 degrees in the fan-shaped notch of the cam plate 15 when the energization of the clutch 19 is stopped and the connection between the cam shaft 11b and the cam plate 15 is released. After the stopper 28 reaches the end of the notch, the rotation of the cam shaft 11b is transmitted to the cam plate 15.

With the above configuration, if the servomotor 4 for driving the table is driven and the grindstone table 2 is advanced to the most advanced position shown in FIG. 1, the servomotor 13 for driving the reciprocating shaft is driven. The cam plate 15 reciprocates according to the amount of eccentricity of the cam plate 15 with respect to the shaft 11, so that the grindstone table 2 performs a fine oscillation operation.

Next, the control means of the eccentric cam mechanism and its control device will be described with reference to the system block diagram of FIG. 4 and the flow chart of FIG.

First, in this embodiment, the control of the table drive motor 4 for performing the traverse motion of the grindstone table 2 and the control of the reciprocating shaft drive motor 13 for oscillating the grindstone table 2 are controlled by the control device 29. Is done.

The control device 29 is composed of a programmable controller and a microcomputer controlled by the controller, and controls the start and stop of driving of the table driving motor and the reciprocating shaft driving motor 13.

Further, in this embodiment, the eccentric cam or cam plate 15
An angle detector 30 for detecting the rotation angle is provided, and timing control is performed so as to stop the eccentric cam, that is, the cam plate 15 at a constant angle when the oscillation operation is stopped.

The control device 29 is provided with an operation panel 31,
Each item related to the feed of the grindstone table 2, that is, a traverse amount and a traverse speed of the grindstone table 2, an oscillation stroke during an oscillation operation, an oscillation cycle, and the like are set on the operation panel 31. The numeric values required for each item are operated with the ten keys, and the data of each of these items is displayed on the CRT display 32.

Further, when changing the oscillation stroke of the grindstone table 2, the energization of the clutch 19 is stopped, the cam shaft 11b and the cam plate 15 are released, and the servo motor 13 for driving the reciprocating shaft is rotated at a predetermined low angle. Let camshaft 11
When the amount of eccentricity between b and the cam plate 15 reaches a predetermined value, the clutch 19 is energized to connect the cam shaft 11b and the cam plate 15. At this time, in the eccentric cam, a table showing the data of the interrelationship between the eccentric angle and the eccentric angle, which is the angle in the direction of rotation of the cam plate 15 with respect to the cam shaft 11b, is input in the control device 29 in advance, The cam shaft 11b is rotated by an angle to obtain an eccentric stroke.

Therefore, as shown in the flow chart of FIG.
First, according to a command from the control device 29, the servo motor 13 is driven to start the oscillation operation of the grindstone table 2, and the encoder 14 reads the number of rotations of the servo motor 13 to perform the oscillation operation for a predetermined time. The driving of the servomotor 13 is stopped by the command of the control device 29, and the oscillation operation is stopped.The timing command for this stop is the signal of the angle detector 30 for stopping the cam plate 15 at a constant angle. Based on this, the controller 29 issues a timing command to stop the cam plate 15 at a constant angle.

Regarding the operation of changing the oscillation stroke of the eccentric cam, it is necessary to first return the cam plate 15 to the original position.

First, the angular position of the dock 27 at the time of a fixed angle stop from the set oscillation stroke is calculated from the output of the angle detector 30. Next, the dock 27 is fixedly stopped at an angular position about 5 ° before the angular position at which the proximity switch 26 is turned on. Then, the power supply to the clutch 19 is stopped, and the reciprocating shaft 11, that is, the cam shaft 11b is rotated at a low speed (about 1 rpm).
Let At this time, the stopper 28 hits the notched end of the cam plate 15, the cam plate 15 rotates together with the cam shaft 11b, and when the dock 27 reaches the angular position where the proximity switch 26 is turned on, the rotation of the servo motor is stopped. Stop.

After setting the cam plate 15 at the origin position in this way, according to the table of the eccentric angle-eccentric stroke, the cam shaft 11b and the reciprocating shaft 11 are rotated by the drive of the servomotor 13 by the eccentric angle to obtain a desired stroke, and then, By operating the operation panel 31, the clutch 19 is energized, the cam shaft 11b and the cam plate 15 are connected, and a desired eccentric stroke can be obtained.

As described above, the cam plate 15 always returns to the eccentric center position when the oscillation operation is stopped, which enables accurate positioning of the grindstone table 2 and the operation panel when changing the oscillation stroke of the cam plate 15. By operating, the oscillation stroke can be adjusted automatically, and the adjustment work of the oscillation stroke becomes significantly easier than before. In addition, the danger of oscillation stroke and oscillation cycle Combinations can be avoided, i.e. interlocked.

In this embodiment, the table driving servomotor 4 is fixed to the lower surface of the grindstone table 2 and the ball screw 6 is used.
Although the nut 7 to be fitted with is set on the table base 1 side, the nut may be fixed to the lower surface of the table and the servo motor 4 for driving the table may be set on the table base 1 side. Of course, those skilled in the art may appropriately perform the above.

<< Advantages of the Invention >> As described above, in the table feed device according to the present invention, the servomotor and the ball screw mechanism are used to drive the traverse movement of the table, and the eccentric cam mechanism is used for the oscillation operation of the table. Therefore, it is possible to perform both low-speed cutting processing and high-speed oscillation processing in an inner surface grinding machine or the like, and the versatility of grinding processing can be greatly improved.

Further, when performing the oscillation operation by the conventional eccentric cam mechanism, it was impossible to accurately position the grindstone table when the oscillation operation was stopped, but according to the present invention, the reciprocating shaft is stopped at a constant angle. The table can always be positioned at an accurate position when the oscillation operation is stopped. In addition, the clutch mechanism that connects and disconnects the eccentric cam is used to easily and reliably change the oscillation stroke of the eccentric cam. Since it is designed to be performed, it is extremely practical in that accurate positioning of the table and adjustment work of the oscillation stroke can be remarkably simplified, and is particularly suitable for an inner surface grinding machine or the like. .

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment in which the table feeding device according to the present invention is applied to a small-sized inner surface grinding machine, FIG. 2 is a vertical cross-sectional view showing a main part, and FIG. 3 is an exploded perspective view showing the same main part. 4 and 5 are system block diagrams accompanying the control of the eccentric cam mechanism used in the present invention, and FIG. 5 is a flow chart diagram thereof. 1 …… Table base 2 …… Whetstone table 4 …… Table driving servo motor 6 …… Ball screw 7 …… Nut 8 …… Encoder 10 …… Eccentric cam mechanism 11 …… Reciprocating shaft 11b …… Cam shaft 13 …… Reciprocating Servomotor for axis drive 14 …… Encoder 15 …… Cam plate 16 …… Clutch plate 17 …… Brake plate 18 …… Cam block 19 …… Clutch 20 …… Slide ring 26 …… Proximity switch 27 …… Dock 28 …… Stopper 29 …… Control device 30 …… Angle detector 31 …… Operating panel 32 …… CRT display

Claims (1)

[Claims] 1. A rotation of a table driving motor is converted into a reciprocating motion of a table via a ball screw mechanism, the table is traversed between a processing standby position and a processing position, and a rotation of a reciprocating shaft driving motor is performed. Is a table feed device for converting the reciprocating motion of the table through an eccentric cam and performing an oscillation operation of the table at a table processing position, wherein the eccentric cam is a cam shaft eccentrically extended on the reciprocating axis, A cam plate rotatably supported by the cam shaft and having an outer periphery eccentrically formed with respect to the cam shaft, a cam block slidably contacting the outer periphery of the cam plate, and the cam block slidably contacting the cam block. A slide ring that converts eccentric rotary motion into reciprocating motion of the table, a clutch mechanism that connects and disconnects the cam shaft and the cam plate, and the cam Of the eccentric cam drive control means is attached to a reciprocating shaft drive motor and reads the rotational position of the reciprocating shaft drive motor. An encoder, an angle detector that detects an eccentric angle that is an angle in a rotation direction of the cam plate with respect to the cam shaft in the eccentric cam, and a control device that controls rotational drive of the reciprocating shaft drive motor, By the command of the control device according to the output of the angle detector, the eccentric cam is stopped at a constant angle, the clutch mechanism is operated, and the cam plate and the cam shaft are connected and released, thereby The cam plate is rotated by a predetermined angle with respect to the cam shaft to adjust the eccentricity of the eccentric cam, and the eccentricity is adjusted to adjust the eccentricity. Table feed apparatus, characterized in that the stroke of Deployment operation is configured to vary.