JPH05352U - Error absorbing tool holder for buff polishing - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] It is applied to automatic polishing equipment such as screws for injection molding machines and screws for extruders, and it is possible to automatically absorb the error of the polishing point of the work, and high precision polishing processing. And the tool life is extended. [Structure] A tool 2 is fitted to a male spline portion S of a tool holder shaft 3a and mounted on a movable spline flange 3b. The springs 3f and 3e are set so that the spline flange 3b can be supported in an equilibrium state at a substantially intermediate position (L ₁ ≈L ₂ ) in a free state. The tool 2 is the side surface 1a of the work groove,
When one side contact 2a is made with either bottom surface 1b, pressing force component P
_{The X} reaction force R is generated, the tool 2 moves by the amount δ, contacts both sides of the groove side surface and the bottom surface, reaches the equilibrium state, and continues the polishing work thereafter.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a buffing tool holder applied to an automatic polishing device for a cylindrical work having screw-shaped troughs such as a screw for an injection molding machine and a screw for an extruder.

[0002]

[Prior Art]

 FIG. 2 is a configuration diagram of a conventional automatic polishing device for a work such as a screw for an injection molding machine having a screw-shaped trough. In the figure, the device is a work drive unit that rotates a work 1 in a direction A via a chuck 9 by a servo motor 10, and a tool posture control robot 6 and a robot loading carriage 7 by a servo motor 11 via a ball screw 8. It has a feed drive unit for moving in the direction X.

A tool rotating head 4 is installed on the tip of the wrist of the robot arm, and an air cylinder 5 is configured to enable a pressing operation P of the buffing tool 2 against the work 1.

The buffing tool 2 is attached to the shaft end of a tool rotary head 4 via a tool holder 3.

FIG. 3 is an overall view of a conventional tool holder 3. The tool holder 3 comprises a holder shaft 3g, flanges 3h and 3i for holding the buffing tool 2, and a tightening nut 3j.

Next, the operation during the actual polishing work will be described. First, the robot 6 brings the buffing tool 2 closer to the polishing point of the work 1, and then the pushing operation is performed by the air cylinder 5, and at the same time the servo motor is operated. A command is given to 10 and 11, and the work drive part and the feed drive part are caused to perform a synchronous movement by linear interpolation, and the tool 2 is guided along the polishing point to perform automatic polishing work.

[0007]

[Problems to be solved by the device]

 By the way, there are the following problems in the polishing work by the conventional automatic buffing device as described above. Fig. 4 shows the relationship between the theoretical tool trajectory and the polishing point of the actual workpiece when polishing the thread groove corners. The tool feeds the theoretical tool trajectory 21 according to preset numerical data and drives the drive axis X and the workpiece rotation. Although guided by linear interpolation control between axes, the actual polishing point 22 of the workpiece is theoretical due to bending due to processing stress in the previous process, bending due to its own weight, changes due to thermal expansion during polishing work, and workpiece mounting error. An error D occurs between the tool path 21 and the tool path 21.

FIG. 5 shows a polishing state by the conventional tool holder 3, and shows a state where the buff polishing tool 2 contacts the work 1 by the pressing force P. 5A shows the case where the tip end surface of the tool 2 contacts the groove side surface 1a of the work 1, and FIG. 5B shows the case where the tool bottom surface 1b contacts the groove bottom surface 1b. At this time, due to the error D, gaps Tr and Ta are generated between the tool 2 and the groove bottom surface 1b and the groove side surface 1a of the work 1, respectively, resulting in unfinished polishing and rapid uneven wear of the tool and dropping of abrasive grains. However, it is often difficult to continue the polishing work thereafter.

For this reason, conventionally, a method has been adopted in which a tool having a weak flexibility and high flexibility, which sacrifices the polishing ability, is selected and the error is absorbed by the tool itself.

However, in order to remove local scratches, scratches, chatter marks, etc. generated in the previous step, it was necessary to reciprocate the tool many times over the entire area of the thread groove of the work to polish the work.

As a result, the polishing work time is inefficient over a long period of time, and the tool is contacted many times. Therefore, excessive polishing is performed to a point where there is no need, and the angle of ridge angle shown in FIG. The portion 1c tends to sag, which is an unfavorable problem in terms of maintaining the original shape accuracy, which is the original purpose of polishing.

The present invention intends to solve the above-mentioned problems and to provide the purpose of extending the life of the tool, improving the efficiency of the polishing work, and ensuring the polishing quality by inexpensive means.

[0013]

[Means for Solving the Problems]

 In order to achieve the above object, the error absorbing tool holder for buffing of the present invention rotates in an automatic polishing device for polishing a screw groove groove corner portion of a cylindrical work having a groove groove on the outer periphery. A spline part is provided on the holder shaft of a rotary tool holder that is attached to a tool feed drive device that is arranged in parallel with the workpiece and is configured to be slidable in the workpiece axis direction. The holding device that holds the tool for polishing is set so that it can slide in the axial direction and can be supported in an equilibrium state at the intermediate position of the entire movement stroke by a restoring means such as a spring. It is characterized in that the tool can be automatically moved to the optimum contact position when it is pressed into the valley groove.

[0014]

[Action]

 The error absorbing tool holder for buffing of the present invention has a spring, etc., which is built in the tool holder and equilibrium means built in.When the buffing tool is pressed against the thread groove corner of the workpiece, the tool holder It is configured so that it can move on the axis to absorb the error, and it automatically absorbs the error between the instruction tool path and the polishing point, and the tool comes into contact with the optimum position of the workpiece for high-precision polishing. In addition to making it possible in a short time, uneven wear of the tool and rapid drop of abrasive grains can be prevented, and the tool life can be extended.

[0015]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall view of an error absorbing tool holder of the present invention. In the figure, 1 is a cylindrical work having a screw-shaped trough such as a screw for an injection molding machine or a screw for an extruder, and 2 is a buffing tool, which is a spline flange fitted to the male spline portion S of the tool holder shaft 3a. It is attached to the outer circumference of 3b.

The tool holder shaft 3a mounted on a tool rotary head (not shown) has a male spline portion S for transmitting a rotational force.

The spline flange 3b has an inner periphery fitted to the outer periphery of the male spline portion S, and is configured to be movable on its axis. The spline flange 3b holds the buffing tool 2 together with the flange 3c by the tightening bolt 3d.

The springs 3f and 3e are in a free state in which the buffing tool 2 is not in contact with the work 1, and the spline flange 3b is in an equilibrium state at approximately the middle of its entire movement stroke, that is, at a position of L ₁ ≈L _2. The setting is built in so that it can be supported.

When performing a polishing operation, the buff polishing tool 2 is pressed by an unillustrated air cylinder (corresponding to the air cylinder 5 in FIG. 2) to bring the tool 2 into contact with the work 1. At this time, if there is an error between the position of the tool 2 and the polishing point of the work 1, the tool 2 makes one-side contact 2a with either the side surface 1a or the bottom surface 1b of the work groove. (In the case shown, it touches the side.)

At this time, a pressing component force P _x is generated, and finally a reaction force R that tries to move the tool 2 and the spline flange 3b on the tool holder shaft 3a is generated, and the buffing tool 2 is It moves by δ until it contacts the bottom surface or side surface (bottom surface in the figure) of the work groove, contacts both sides of the groove surface and the bottom surface, reaches the equilibrium state, and continues the subsequent polishing work.

Further, during the polishing work, an error D is generated between the theoretical tool locus 21 and the actual polishing point 22 of the work as shown in FIG. 4 due to bending of the work 1 or the like, but due to the groove corner of the work 1. By the centering action, it is possible to absorb the error within the movable range of the spline flange 3b while maintaining the contact on both sides.

In this embodiment, the spring is used as the restoring balance means, but a high-sensitivity error absorbing function is realized by avoiding the influence of the imbalance of the pressing force components on both sides of the contact surface due to the deflection of the spring. To achieve this, the same object can be achieved by controlling the air pressure using the tool holder shaft core as the supply hole as the restoring balancing means.

[0023]

[Effect of the device]

 According to the error absorbing tool holder for buffing of the present invention, the following effects can be obtained. (1) Since the error between the theoretical command tool path and the polishing point of the actual work can be automatically absorbed, even if the abrasive grain of the buffing tool falls off and wears and the outer diameter changes, the polishing point of the corner of the work can be reliably performed. The tool follows and the tool can be polished in a short time with high polishing ability. (2) It is possible to reliably remove scratches and scratches on the polishing point of the workpiece with one pass of the tool, enabling highly accurate polishing. (3) In addition, uneven wear of the tool due to one-sided contact and rapid drop-off of abrasive grains are eliminated, so that the tool life can be extended.

[Brief description of drawings]

FIG. 1 is an overall view of an error absorbing tool holder according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional automatic buffing device.

FIG. 3 is an overall view of a conventional tool holder.

FIG. 4 is a relationship diagram between a theoretical tool path and a polishing point of an actual work.

FIG. 5 is an explanatory view of a polishing state using a conventional tool holder,
(A) shows a state where the tool is in contact with the side surface of the work groove,
(B) is a sectional view showing a state in which the tool is in contact with the bottom surface of the work groove.

[Explanation of symbols]

 1 Work 2 Buff Polishing Tool 3 Tool Holder 3a Tool Holder Shaft 3b Spline Flange 3c Flange 3d Tightening Bolt 3e, 3f Spring S Male Spline Part

Claims (1)

[Claims for utility model registration] 1. An automatic polishing device for polishing a threaded groove corner portion of a cylindrical work having a threaded groove on the outer periphery thereof is arranged in parallel with the rotating work. A holding device for attaching a buffing tool is provided on a holder shaft of a rotary tool holder that is attached to a tool feed drive device and is configured to be slidable in the work axis direction, and holds a buffing tool on the spline shaft. It is set so that it can slide in the axial direction and can be supported in an equilibrium state at the intermediate position of the entire movement stroke by a restoring means such as a spring, and when the buffing tool is pressed against the groove of the workpiece during polishing, An error absorbing tool holder for buffing, characterized in that it can be automatically moved to the optimum contact position.