JPH07237098A - Polishing method for inside of bent pipe and polishing device therefor - Google Patents

Abstract

PURPOSE:To prevent a nonpolished part from remaining in the middle part of the inside of a bent pipe by prescribedly positioning a polishing tool attached to the tip of a polishing spindle making rotary motion and annual variation motion in a work which is prescribedly held in a work holding part and has a fixed shape, and advancing and rotatively displacing the work holding part with the rotation and annual variation motion of the polishing spindle. CONSTITUTION:A polishing tool 2 is attached to the tip of a polishing spindle 1 making rotary motion and annual variation motion. The work holding part 3 can move forward and backward and rotate in the direction of the symmetrical axis A of the annual variation motion. A work W composed of a 1/4 circular pipe whose end faces are mutually perpendicular is held so that the pipe center of one end face W may coincide with the rotary center O1 of the work holding part 3. The plane direction of the one end face W1 of the work W is made to cross the symmetrical axis of the annual variation motion at right angles. The polishing tool 2 is inserted into the work W from the end face W1, and the work holding part 3 is advanced and rotatively displaced as the rotation and annual variation motion of the polishing spindle are made for polishing up to the inside middle position of the work W. Next the work W is similarly polished from the opposite end W2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method and a polishing apparatus for polishing an inner surface of a curved pipe such as an elbow pipe with a buff or the like, and in particular, both end faces form an angle of 90 degrees with each other. It is preferably used for polishing the inner surface of a four-arc tube.

[0002]

2. Description of the Related Art Conventionally, as a polishing device for an inner surface of a pipe, a device disclosed in Japanese Patent Application Laid-Open No. 1-264752 and a device disclosed in Japanese Patent Application Laid-Open No. 3-79259 proposed by the present applicant are known. . In these polishing devices, the main body of the polishing machine is equipped with a polishing main shaft for mounting a polishing tool at its front end and a polishing motor for driving the rotation of the polishing main body.In the former case, two main pivots for horizontal rotation and vertical rotation are used. It is installed on a slide base, and in the latter, it is supported by a mounting frame through a spherical bush fitted in a spindle holder so as to be swingable in the forward direction. An air cylinder attached to the front end holds the rear part of the main body of the polishing machine, which is located on the axis of the polishing main shaft, in a state of being eccentric from the axis of the drive shaft. The precession of the polishing spindle is integrated with the main body of the polishing machine (the rotating shaft of the rotating body rotates with a fixed inclination angle with respect to the immobile symmetric axis like a spinning mandrel). Has been done.

However, the former (Japanese Patent Laid-Open No. 1-264752).
In the device disclosed in Japanese Patent Publication No. 3), the sliding table having the polishing machine main body and the entire swing mechanism mounted thereon is moved forward, and in the latter (Japanese Patent Laid-Open No. 3-79259), the workpiece feeding table is installed in front of the polishing machine main body. The inner surface is polished by inserting a polishing tool such as a buff at the tip of the polishing spindle that rotates and precesses into the inside of the tubular work, and elastically pressing the rotating polishing tool while revolving around the tube. In this case, in the former device, only the straight pipe portion of the work can be ground internally, whereas in the latter device, the slider of the work feed table is provided with a work support plate rotatable about an axis orthogonal to its moving direction. With this configuration, the inner surface of the curved portion of a curved pipe such as an arc elbow can be polished by rotationally displacing the support plate while advancing the support plate.

[0004]

The inner surface of a circular arc tube is ground by an inner surface polishing device having a rotatable work supporting plate on the latter work feed table. Arranged so as to coincide with the circumference centered on the rotation axis, the end surface of one end side of the circular arc tube on which polishing should be started has a phase difference of 90 degrees with respect to the moving direction of the work feed base, The center of the side is aligned with the symmetry axis of the precession movement of the polishing spindle, and in this state the polishing spindle is rotationally driven and precessed, and at the same time the workpiece support plate is moved forward while rotationally displacing the polishing tool into the arc tube. It is done by letting.

However, in this inner surface polishing method, since the circular arc tube is rotationally displaced along the circumference centered on the rotation axis of the work support plate, when the tip of the polishing tool enters the circular arc tube to a certain extent, If the shaft part of the polishing tool that is moving in a differential manner interferes with the opening edge of the arc tube, and the arc tube is the most common 1/4 arc (90 °),
Before the tip of the polishing tool reaches the middle part of the arc tube, the polishing limit is reached, and even if the arc tube is polished in the same way with both ends reversed, an unpolished part will remain in the middle part of the inner surface. There were difficulties.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention has a simple device structure and leaves an unpolished portion in the middle portion even if the work is a curved pipe such as a quarter-arc pipe. It is an object of the present invention to provide an inner surface polishing method capable of surely polishing the entire inner surface and an inner surface polishing apparatus used therefor.

In order to achieve the above object, the present invention is claimed.
The method for polishing the inner surface of the curved pipe according to item 1 is such that the precession while rotating
When the polishing tool 2 is attached to the tip of the polishing spindle 1 that moves.
Both move forward and backward along the symmetry axis A direction of this precession
Centered on an axis that is possible and orthogonal to its direction of movement
Then, the work holding part 3 which can be rotated is rotated by 90
Workpiece W consisting of a 1/4 circular arc tube that makes an angle of
W₁Is the center of rotation O of the work holder 3.₁Matches
So that the one end W of this work W is ₁Side of
The direction is orthogonal to the symmetry axis A of the precession and the end W
₁The arrangement is such that the center of the pipe is on the axis of symmetry A.
And the one end W₁Position the polishing tool 2 inside the opening of
The rotation of the polishing spindle 1 and precession
For polishing by sliding the polishing tool 2 onto the inner surface of the workpiece W
The work holder 3 is moved forward while being rotationally displaced.
The polishing tool 2 to a position approximately in the middle of the inner length of the work W.
It adopts a configuration characterized by making it enter with
It

According to a second aspect of the present invention, in the polishing method according to the first aspect, while the polishing tool 2 moves from the polishing start position to the intermediate point P of the inner length of the work W, the work holding part 3 is provided.
Is employed to rotationally displace within a range of 22 to 25 degrees.

On the other hand, in order to achieve the above-mentioned object, the polishing apparatus for the inner surface of the curved pipe according to claim 3 of the present invention has a fixed mounting frame 4 on which a polishing spindle 1 for mounting a polishing tool 2 at its front end and its rotation. A polishing machine main body 6 having a driving polishing motor 5 is held in a swingable state which allows the precession movement of the polishing main spindle 1, and is located at the rear of the polishing machine main body 6 on the axis of the polishing main spindle 1. And a swinging drive shaft 8 on the symmetry axis W of the precession and a rotation driving motor 9 for the swinging drive. An eccentric air cylinder 1 for holding the swing holding portion 7 at the front end of the shaft 9 in a state of being eccentric from the axis of the drive shaft.
0 is provided, while the main body 6 is provided in front of the main body 6.
A work feed base 11 that is movable in the perspective direction is installed to the work feed base 11, and a work holding unit 3 that is rotatable about an axis orthogonal to the moving direction is attached to the work feed base 11. The work feed base 1
The configuration is provided with an interlocking mechanism that rotationally displaces with the movement of 1.

According to a fourth aspect of the present invention, the interlocking mechanism in the polishing apparatus according to the third aspect is a guide rod 13 in which the one end 13a side is pivotally attached to the fixed portion 12d so as to be rotatable in the rotation surface direction of the work holding portion 3. The other end 13b side is pivotally attached to a position deviated from the rotation center O ₁ of the work holding portion 3.

According to a fifth aspect of the present invention, the interlocking mechanism in the polishing apparatus according to the third aspect is provided with a long hole 1 provided at one of the position deviated from the rotation center O ₁ of the work holding part 3 and the fixed part.
4a, 14b, guide pins 15a, 15 provided on the other side
It is configured by loosely fitting and engaging b.

According to a sixth aspect of the present invention, the interlocking mechanism in the polishing apparatus of the third aspect is such that the fixed rack 16 along the moving direction of the work feed base 11 and the work holding portion 3 are concentric with the rotation axis thereof. It is configured by meshing with the pinion gear 17 that is fixed.

[0013]

According to the polishing method of claim 1, the work holding portion 3 can be moved forward and backward along the symmetry axis A direction of the precession movement of the polishing spindle 1 and can be rotated about an axis orthogonal to the movement direction. In this work holding part 3, a work W consisting of a quarter-arc pipe whose both end surfaces form an angle of 90 degrees with each other is provided, and the pipe center at one end W ₁ is the rotation center O of the work holding part 3.
Hold it to match ₁ . Then, when polishing is started, an arrangement state in which the surface direction of the one end W ₁ of the work W is orthogonal to the symmetry axis A of the precession and the pipe center of the one end W ₁ is on the symmetry axis A. At one end W ₁
In order to position the polishing tool 2 inside the opening (see the solid line in FIG. 6), the polishing spindle 1 is rotationally driven and precessed to bring the polishing tool 2 into sliding contact with the inner surface of the work W while polishing. When the work holding part 3 is moved forward while being rotationally displaced, the work W is kept in a state where the axis of symmetry A of the precession movement of the polishing spindle 1 coincides with the center of the pipe on the one end W ₁ side which is the polishing start side. , The other end W ₂ side is rotationally displaced so as to approach the symmetry axis A (see the phantom line in FIG. 6).

Therefore, while the polishing spindle 1 is rotationally driven and precessed to bring the polishing tool 2 into sliding contact with the inner surface of the work W for polishing, the work holding portion 3 is moved forward while being rotationally displaced to perform the polishing. Without causing interference between the shaft portion 2b of the tool 2 and the opening edge of the workpiece W on the polishing start side, the tip 2a of the polishing tool 2 is advanced to a position beyond the intermediate point P of the workpiece W to perform internal polishing. be able to.
Then, after the inner surface is polished, the work W is fixed at both ends W ₁ , W ₂
By performing an operation similar to the above by substituting the arrangement in which is reversed, the entire inner surface of the work W can be polished completely.

When a workpiece W consisting of a quarter-arc pipe whose both end surfaces form an angle of 90 degrees with each other as described above is to be polished, the polishing tool 2 is moved from the polishing start position to the polishing start position. If the work holding portion 3 is set to be rotationally displaced within an angle range of 20 to 25 degrees while approaching the intermediate point P of the inner length of the workpiece W, the tip 2a of the polishing tool 2 comes near the intermediate point P. At this time, the symmetry axis A of the precession movement of the polishing spindle 1 does not largely deviate from the center of the pipe at that position, so that the pressing force of the polishing tool 2 against the inner surface of the pipe changes in the circumferential direction even near the intermediate point P. As a result, the inner surface of the tube becomes more uniform in polishing degree. On the other hand, the angle is 2
When it is set to be less than 0 degrees or more than 25 degrees, the pressing force of the polishing tool 2 greatly changes in the circumferential direction in the vicinity of the intermediate point P due to the deviation between the center of the pipe and the axis of symmetry A. The difference in the degree of polishing along the line significantly deteriorates the polishing quality.

In the polishing apparatus of claim 3, the polishing machine main body 6 is held by the fixed mounting frame 4 in a swingable state which allows the precession movement of the polishing spindle 1, so that the eccentric air cylinder 10 is provided. When the swinging drive shaft 8 is rotationally driven with the swinging holding portion 7 of the main body 6 being eccentric, the entire main body 6 swings, but the swinging holding portion 7 is positioned on the axis of the polishing spindle 1. Therefore, the swinging causes the polishing spindle 1 to perform a precession movement, and the tip 2a of the polishing tool 2 attached to the front end of the polishing spindle 1 circularly moves. The magnitude of this circular movement, that is, the diameter, is determined by the distance between the swinging holding portion 7 and the tip 2a of the polishing tool 2 with respect to the center of convergence of the precession and the eccentricity of the swinging holding portion 7. It can be arbitrarily set by adjusting with the air cylinder 10 for use.
Therefore, after the magnitude of the circular motion is appropriately set according to the inner diameter of the work W, the tip 2 of the polishing tool 2 is placed in the work W.
By positioning a and rotating the polishing main shaft and the swinging drive shaft, the polishing tool 2 rotates at high speed and slides along the inner circumference of the workpiece to achieve the required polishing action. At this time, since the swing holding portion 7 is held eccentrically by the air cylinder 10, the polishing tool 2 elastically presses the inner surface of the work W based on the air elasticity peculiar to the air cylinder. .

On the other hand, the work holding part 3 is attached to a work feed base 11 which is movable in the perspective direction with respect to the main body 6 of the sander so as to be rotatable about an axis perpendicular to the moving direction, and an interlocking mechanism. Due to the movement of the work feed base 11, the work feed base 11 is rotationally displaced. Therefore, when applying the polishing method as described in claim 1 and claim 2, by appropriately determining the relationship between the movement of the work feed base 11 and the rotational displacement of the work holding portion 3, the work feed base 11 can be obtained. In the process of moving to a fixed position, the work W is automatically rotationally displaced,
It can be set so that the inner surface polishing to the position beyond the intermediate point P is completed.

Explaining this with reference to FIG. 6, the work W, which is held by the work holding portion 3 and is made up of a quarter-arc tube, is
At the start of polishing, as shown by the solid line in the figure, the surface direction of one end W ₁ on the polishing start side is the symmetry axis A of the precession movement of the polishing spindle 1.
And the tip 2a of the polishing tool 2 is located inside the opening at one end W ₁ thereof. At this time, the tube center at the one end W ₁ is on the rotation axis of the work holding part 3, the symmetry axis A passes through the tube center, and the plane direction of the other end W ₂ is parallel to the symmetry axis A. ing. In this figure, the polishing main shaft 1 is shown on the symmetry axis A of the precession movement.

When polishing the inner surface of half of the entire length of the work W, the tip 2a of the polishing tool 2 extends from one end W _{1 of the} work W to the intermediate point P of the pipe axis B, but in the middle. Assuming that the axis of symmetry A coincides with the center of the pipe in order to make the degree of polishing in the circumferential direction constant at the point P, the work W at the end of polishing becomes the arrangement state shown by the phantom line (two-dot chain line) in the figure. It should be. This is because the work holding part 3 in the polishing start posture shown by the solid line in the figure
It means that it has moved forward along the axis of symmetry A by the straight line distance d between the tube center of one end W ₁ and the intermediate point P, and has been rotationally displaced by the angle θ ₂ . This angle θ ₂ is the center of curvature S _{1 of the} work W.
Is 1/2 of the opening angle θ ₁ between the center of the tube at one end W ₁ and the intermediate point P, and θ ₁ is 45 degrees, so 22.5
It becomes degree. That is, it may be set so as to be rotationally displaced by 22.5 degrees while the work holding unit 3 moves by the distance d. If the tip 2a of the polishing tool 2 only reaches the intermediate point P, the unpolished portion may remain on the outer arc side of the inner surface of the work at the intermediate point P position. Move it slightly ahead of the position of the virtual line.

There is no particular limitation on the mechanism for interlocking the movement of the work feed base 11 and the rotational displacement of the work holding portion 3 as described above, but a very simple structure ensures the interlocking and ensures the interlocking. -The interlocking mechanism of Claim 6 is mentioned. That is, in claim 4, the guide rod 13 is pivotally mounted at a position deviated from the rotation center O ₁ of the work holding part 3, and in claim 5, the guide rod 13 is also deviated from the rotation center O _{1 of the} work holding part 3 and the fixed part. Engage with each other through the elongated hole 14 and the guide pin 15, and in the sixth aspect, the fixed rack 16 and the pinion gear 17 of the work holding portion 3 mesh with each other. The work holding part 3 is automatically rotationally displaced. Further, in claim 4, the guide rod 13 is pivotally attached, in claim 5, the elongated hole 14 and the guide pin 15 are engaged with each other, and in claim 6, the diameter of the pinion gear 17 is used. The rotational displacement angle of the work holding part 3 with respect to can be set appropriately.

[0021]

1 to 3 show a polishing machine body 6 and a rocking device 18 in first to fourth embodiments of the present invention. Polisher body 6
Are side wall portions 19a of the U-shaped machine frame 19 having an upward U-shape in side view,
A cylindrical spindle holder 20 installed between 19a, a polishing motor 5 fixed to the lower surface of the bottom wall 19b of the machine frame 19, and an L-shaped arm 21 extending rearward from the base frame 19. I have it. The polishing spindle 1 is rotatably held by the spindle holder 20 via bearings 20a, 20a. The spindle 1 has a polishing tool 2 having a buff 2a at the front end thereof via the tool holder 1a. It is mounted and rotated by driving the polishing motor 5 via the pulleys 22a and 22b and the V belt 23c. A shaft-shaped swinging holding portion 7 is fixed to the tip of the L-shaped arm 21 so as to project rearward along the axis of the polishing spindle 1, and a roller 7a is rotatably attached to the tip thereof. ing.

Reference numeral 4 denotes a vertical plate-shaped mounting frame, and a spindle holder 20 horizontally penetrates through a bearing 4a fixedly mounted on the mounting frame. The main shaft holder 20 is pivotally supported by the bearing 4a via the spherical bush 24, so that the main body 6 is supported by the mounting frame 4 so as to be swingable in all directions.

The rocking device 18 includes a rocking drive shaft 14 horizontally arranged via a pair of bearings 25a, 25a fixed on a horizontal plate-shaped mounting frame 25, and the lower surface side of the mounting frame 25. Has a rotation driving motor 9 fixed via an L-shaped mounting bracket 25b, and the swing driving shaft 8 is rotated by driving the motor 9 via pulleys 22c and 22d and a timing belt 23b. It is done like this. A disk 26 is concentrically fixed to the front end of the drive shaft 8, and a pair of angle members fixedly opposed to each other are provided on the front surface of the disk 26 as shown in FIG. Two
A radial guide groove 27 formed between 7a and 27a,
An eccentric air cylinder 1 fixedly mounted via an L-shaped mounting piece 20a so that the rod 10a faces one side of the guide groove 27.
0, the U-shaped mounting piece 26b is movably held in the axial direction so as to face the air cylinder 10 with the guide groove 27 interposed therebetween, and the coil spring 28 urges the guide groove 27 to project into the guide groove 27. Push pin 2 biased to
9 is provided. Reference numeral 30 is a rotary joint for connecting a hose for supplying compressed air to the air cylinder 10.

The axis of the swing drive shaft 8 is the main body 6
It is set so as to pass through the center of swing by the spherical bush 24 of the air cylinder 10, and the roller 7a of the swing holding portion 7 of the main body 6 is fitted in the guide groove 27 so that the rod 10 of the air cylinder 10 can be fitted.
It is set so as to be sandwiched between a and the pressing pin 29. Therefore, when the air cylinder 10 is extended and driven, as shown in FIG.
When the roller 7a is pressed by 0a, the roller 7a is decentered from the axis of the swing drive shaft 8, and accordingly, the entire main body 6 tilts around the swing center point Q of the spherical bush 24.
Then, by rotating the swing drive shaft 8 in the eccentric state, the roller 7a makes a circular motion, so that the polishing main shaft 1 of the main body 6 precesses, and the polishing tool 2 attached to the tip thereof. The buff 2a goes around in a circle.

FIGS. 4 and 5 show the work feed base 11 according to the first embodiment installed in front of the main body 6 of the sander. The work feed base 11 is slidably supported in the front-rear direction by two guide rods 31, 31 arranged on the base frame 12 along the horizontal front-rear direction via ball bushings 11a, 11a, and also on one side. To the bracket 11c fixed to the
A rod 32a of a work feeding cylinder 32 having a base end fixed to a rear horizontal frame 12a of the base frame 12 is connected,
The work feed table 11 is configured to move back and forth by the operation of the cylinder 32. The work holder 3 is rotatably hindered on the work feed base 11 via the vertical support shaft 3a inserted into the bearing 11b. The position is set so that the axis of symmetry A of the precession of the polishing spindle 1 passes along the line.

The work holding portion 3 has a horizontal rotary disc 32 having a vertical support shaft 3a fixed to the center of the lower surface thereof, and the rotary disc 33.
It is composed of a work receiving plate 34 which is bolted to the top. The work receiving plate 34 has a shape in which one corner of a rectangular plate is cut off, and three work positioning pieces 35a, 35 in the form of a vertical plate having a V-shaped recess fixedly provided on the upper surface side thereof.
On the b and 35c, a work W consisting of a quarter-arc tube whose both ends W ₁ and W ₂ form an angle of 90 degrees with each other, such as a 90-degree elbow, is placed, and a semi-arc shape is formed on the intermediate positioning piece 35b. By fixing the workpiece fixing piece 36 of the workpiece W with the bolts 36a, 36a, the pipe center of one end W ₁ of the workpiece W is on the rotation axis of the workpiece holding portion 3, and the tube axis is the polishing spindle 1. The precession is fixed in a state where it is flush with the symmetry axis A of the precession.

Further, a strip plate-shaped bracket 34a is provided on the work receiving plate 34 so as to project from the side portion facing the other end W _{2 of the} work W, while the guide rod 1 is provided on the front frame 12b of the machine frame 12.
3 is pivotally mounted at one end 13a via a pin 37a so as to be horizontally rotatable, and the other end 13b of the guide rod 13 and the bracket 34a are relatively rotatably connected via a pin 37b. Due to the connection between the work receiving plate 34 and the guide rod 13, the work holding portion 3 is rotationally displaced along with the forward and backward movement of the work feed base 11, but one end of the work W held as shown by the solid line in FIG. When the surface direction of W ₁ is in an arrangement posture orthogonal to the moving direction of the work feed base 11, the buff 2a of the polishing tool 2 mounted on the polishing spindle 1 is placed inside the opening on the one end W ₁ side of the work W. Positioned for placement. Therefore, the relationship between the movement of the work feed table 11 and the rotational displacement of the work holding portion 3 is as follows.
Depending on the connecting position of 4 and the guide rod 13, the work feed base 11
Is set so that the workpiece holder 3 is rotationally displaced by an angle of 22.5 degrees while moving by a linear distance between the center point of one end of the workpiece W and the midpoint of the tube axis.

In order to polish the inner surface of the work W with the above-described polishing apparatus, first, the work W is set in the work holding portion 3 at a position where the work feed base 11 is slightly retracted from the position shown by the solid line in FIG. After that, the work feed table 11
By advancing to the polishing start position shown by the solid line in FIG. 5, the buff 2a of the polishing tool 2 is arranged inside the opening on the one end W ₁ side of the work W. And the eccentric air cylinder 1
By setting 0, the circular movement outer diameter of the buff 2a accompanying the precession movement of the polishing spindle 1 is set to be slightly larger than the inner diameter of the work W, and
The polishing motor 5 and the rotation driving motor 9 are driven to rotationally drive and precess the polishing spindle 1, and in this state, the work feed table 11 is gradually advanced at a speed according to the desired polishing degree. As a result, the buff 2a, which rotates at a high speed, makes a circular motion while contacting with the inner circumference of the work W at a constant pressure and exerts a polishing action, but the work W has a polishing spindle 1 at the center of the pipe at one end W _1. Since the other end W ₂ side is rotationally displaced so as to approach the symmetry axis A while the symmetry axis A of the differential motion remains the same, the opening of the shaft portion 2b of the polishing tool 2 and one end W ₁ of the work W is opened. The buff 2a can be reasonably advanced to a position slightly beyond the intermediate portion of the work W without causing interference with the edge portion.

Thus, when the inner surface polishing of the work W to a little over half the length is completed, the work feed table 11 is retracted to the position where the buff 2a is separated from the work W, and the work W is removed.
Is replaced with an arrangement in which both ends W ₁ and W ₂ are reversed, and the unpolished portion on the opposite side is polished in the same manner as described above, whereby the entire inner surface of the work W is completely polished. It According to this polishing, since the center of the pipe at the polishing position of the work W does not largely deviate from the symmetry axis A of the precession movement of the polishing main shaft 1 from the start to the end of polishing, the circumference of the pressing force against the inner surface of the buff 2a against the pipe is reduced. Direction change is small,
In addition, the swing holding portion 7 is eccentrically held by the air cylinder 10 and elastically presses against the inner surface of the buff 2a work W based on the air elasticity peculiar to the air cylinder, so that the entire inner surface has a uniform degree of polishing. Therefore, high polishing quality can be secured.

Here, in the polishing apparatus of the first embodiment,
For setting the pivoting position between the work receiving plate 34 and the guide rod 13
The method will be described with reference to FIG. That is, the work
When polishing half of the total length of W, the buff 2a is the work
One end of W W₁To approach the midpoint P of the tube axis B
At this intermediate point P, the degree of polishing in the circumferential direction is
If the axis of symmetry A is made to coincide with the center of the tube in order to make it constant,
If so, the arrangement shown by the solid line in the figure was at the start of polishing.
Work W is shown by phantom line (two-dot chain line) at the end of polishing
It should be in the arranged state. This is the work receiving part 3 times
Turning center O₁Is O ₂To the intermediate point P of the pipe axis B of the workpiece W
O₁Respectively to one end of the work W₁Face direction
Is the angle θ₂It has changed only. In other words, the work receiving
The cage 3 has a rotation center O before movement.₁And the axis B of the workpiece W
Forward along the axis of symmetry A by a straight line distance d from the intermediate point P of
In the process of₂Only rotational displacement is required. S₁，
S ₂Is the center of curvature of the workpiece W before and after displacement, and the workpiece W
Center of curvature S of₁Center of rotation O at₁And the intermediate point P
Opening angle θ₁Is 45 degrees, the angle θ₂Is θ ₁of
It becomes 1/2, which is 22.5 degrees.

In order to rotate and displace the work holding portion 3 by 22.5 degrees with the movement of the distance d due to the pivotal connection with the guide rod 13, the guide rod 13 rotates about the fixed point F. The pivot point is such that the distance to the rotation center O ₁ before the movement of the work holding part 3 is equal to the distance to the rotation center O ₂ after the movement, and the parallax angle between both rotation centers O ₁ and O ₂ is It is necessary to set the point C ₀ to be 22.5 degrees (θ ₂ ). The distance L from the point C ₀ to the rotation center point O ₁ (O ₂ ) is, when the radius of curvature of the tube axis B of the work W is r,
Since the distance d = 2r × sin θ _2, it is as follows. L = (d / 2) × [1 / sin (θ ₂ /2)]=r×sin(22.5°)/sin(11.25°)≈1.96r

There is no restriction on the position of the fixed point F which pivotally attaches the one end 13a of the guide rod 13, and therefore the arrangement of the guide rod 13 need not be parallel to the symmetry axis A of the precession.
The length can also be set arbitrarily. However, when the center of rotation of the work receiving portion 3 moves from O ₁ to O ₂ , the pivot point causes a movement to return slightly away from the axis of symmetry A. The part 3 cannot move back and forth.

However, as in the second embodiment shown in FIG. 8, the point C _0, which is the pivot point of the first embodiment, is provided through the elongated hole 14a provided in the bracket 34a for the work receiving plate 34.
According to the structure in which it is rotatably connected to the fixed guide pin 15a provided at the position, the connecting point can be moved along the elongated hole 14a, so that the work receiving portion 3 is the same as in the first embodiment. It can be set so as to be rotationally displaced by 22.5 degrees with the movement of the distance d. Note that, contrary to the second embodiment, the fixed side may have a long hole, and the guide hole fixed to the work receiving plate 34 side may be engaged with the long hole.

On the other hand, the point at which the parallax angle with respect to both the rotation centers O ₁ and O ₂ before and after the movement of the work receiving portion 3 is 22.5 degrees is that the point C ₀ and one end W before and after the displacement of the work W.
There are innumerable points including the intersection C _{1 in} the plane direction of ₁ , but these are all on the circumference C indicated by the broken line in the figure like points C _{0 to} C ₄ in FIG. 7, for example. The circumference C is a radius distant from both the rotation centers O ₁ and O _{2 by a} radius of curvature r of the pipe axis B of the work W, that is, a center of curvature S ₂ of the work W after rotational displacement. It is the circumference of r (the radius of curvature r of the tube axis B of the work W). If the work receiving portion 3 is rotatably held at the fixed point on the circumference C, the work receiving portion is rotationally displaced by 22.5 degrees while the work receiving portion 3 moves by the distance d. At fixed points other than the point C ₀ , the distance to the rotation center O ₁ before the movement is different from the distance to the rotation center O ₂ after the movement, so in order to cope with this distance change, for example, the third embodiment of FIG. As in the example, the engaging structure of the elongated hole and the guide pin may be adopted.

That is, in this third embodiment, the fixed guide pin 15b provided at the position of point C ₂ in FIG. 7 has the elongated hole 14b provided in the bracket 34a of the work receiving plate 34.
8 and the engaging position of the guide pin 15b on the base end side of the elongated hole 14b in the state before the movement of the work receiving portion 3 shown by the solid line in FIG. Along with this, it moves to the tip side of the elongated hole 14b, and the work receiving plate 34 is rotationally displaced with it, and this rotational displacement reaches 22.5 degrees, and the arrangement state shown by the imaginary line in the figure is obtained. The position of the guide pin 15b is not limited to the point C ₂ , but may be any position on the circumference C indicated by the broken line in FIG. 7, and the two rotation centers O ₁ and O ₂ before and after the movement of the work receiving portion 3 from that position. The length and the forming position of the long hole 41 may be set according to the difference in distance. Contrary to the example, it is also possible to adopt a structure in which the fixed side has a long hole and a guide pin fixed to the work receiving plate 34 side is engaged with this long hole.

In the above-mentioned first to third embodiments, the structure in which the work holding part 3 is rotationally displaced by the guide rod 13 or the fixing pins 39, 40 has been exemplified, but in the present invention, the work holding part 3 is moved forward and backward. Various other means can be adopted for rotating and displacing. For example, as in the fourth embodiment shown in FIG. 9, the rack 16 is arranged parallel to the axis of symmetry A of the precession movement of the polishing spindle 1, and the work holding portion 3 is provided with a pinion gear 17 concentric with the rotation axis thereof. It can be configured to be fixed, and by the engagement of the rack 16 and the pinion gear 17, the work holding portion 3 can be rotationally displaced along with the forward and backward movement. In this case, since the rotation amount of the work holding portion 3 due to the front-back movement is determined by the diameter of the pinion gear 17, for example, in order to rotationally displace the work holding portion 3 by 22.5 degrees while moving the work holding portion 3 by the distance d, the pinion gear 17 is set. The diameter may be set such that 1/16 of the circumference is d.

In each of the above examples, the polishing
The tip 2a of the tool 2 is one end W of the work W ₁More inside tube axis B
The explanation was made assuming that the approach point P was entered, but the actual polishing
Then, if you just enter the middle point P, you will reach the middle point P position.
There is a risk of leaving an unpolished part on the outer arc side of the inner surface of the workpiece.
Therefore, the work holding unit 3 is actually positioned at the position of the imaginary line in the figure.
It is better to move it a little further forward. Also, a grinder
The tip 2a of the tool 2 is one end W of the work W₁More inside tube axis B
The rotational displacement of the work holding portion 3 during the approach to the intermediate point P is an angle.
22.5 degrees (1/16 rotation) is ideal, but
The diameter of the W, the buff 2a of the polishing tool 2 and the shaft 2b
Due to the diameter difference, etc., the rotational displacement is within an angle range of 20 to 25 degrees.
You can choose.

In the present invention, the eccentric air cylinder 10 of the rocking device 18 is rotatably mounted in the plane including the axis of the rocking drive shaft 8, and the rod 10 of the air cylinder 10 is attached.
Alternatively, a may be pivotally connected to the swinging holding portion 7 of the polishing machine body 6. Further, the polishing machine main body 6 of the embodiment is held by the mounting frame 4 via the spherical bushes 24 so as to be swingable in all directions. The polishing machine main body 6 is pivotally supported horizontally and vertically. Even if it is held by the mounting frame by means of and, the precession movement of the polishing spindle 1 becomes possible. Further, in the polishing apparatus of the present invention, the type of the polishing tool 2, the shape of the work feed base 11 and the back-and-forth moving means, the structure of the work holding portion 3,
The design of the detailed structure of the work holding unit 3 such as the holding unit for the work W can be changed in addition to the embodiment.

[0039]

According to the polishing method of the first aspect of the present invention, the work holding part is held in the work holding part in a specific arrangement state, and the rotary driving and The polishing tool held at the tip of the precessing polishing spindle slides on the inner surface of the work piece while polishing, while the work holding part is moved forward while being rotationally displaced. The inner surface can be polished by causing the tip of the polishing tool to enter a position beyond the intermediate point in the work without causing interference with the opening edge of
After this inner surface polishing, the work is replaced with the arrangement in which both ends are reversed, and the same operation as described above is performed, whereby the entire inner surface of the work can be completely and uniformly ground.

According to the second aspect of the invention, in the polishing method of the first aspect, while the polishing tool is moving from the polishing start position to the midpoint of the inner length of the work, the work holding portion is moved to the angle of 2.
Since it is rotationally displaced in the range of 0 to 25 degrees, the circumferential change of the pressing force of the polishing tool against the inner surface of the pipe is small even in the vicinity of the intermediate point in the work, so that the polishing degree of the entire inner surface of the pipe can be made more uniform. Therefore, there is an advantage that a high polishing quality can be secured.

According to the invention of claim 3, as a polishing apparatus to which the polishing methods of claims 1 and 2 can be preferably applied, the polishing tool is structurally simple, and the tip of the polishing tool by precession movement of the polishing spindle is The size of the circular motion can be set freely according to the workpiece inner diameter, and the workpiece is automatically rotationally displaced by the required amount in the process of moving the workpiece feed table to the fixed position, and thus to the position beyond the midpoint in the workpiece. Are provided which can complete the internal polishing of.

According to the fourth to sixth aspects of the invention, as the polishing apparatus of the third aspect, the rotational displacement operation associated with the back-and-forth movement of the work holding portion can be automatically performed by an extremely simple structure, and the rotation thereof can be performed. Provided is one that can reliably and stably maintain the set value of the displacement.

[Brief description of drawings]

FIG. 1 is a side view showing a polishing machine body and a rocking device of a polishing apparatus according to first to fourth embodiments of the present invention.

FIG. 2 is a sectional view taken along the line II-II of FIG.

FIG. 3 is a schematic side view for explaining the operating principle of the precession movement of the polishing spindle in the polishing apparatus.

FIG. 4 is a side view of a work feed table in the polishing apparatus according to the first embodiment of the present invention.

FIG. 5 is a plan view of the work feed base.

FIG. 6 is a schematic plan view explaining the principle of the work feeding operation by the work feeding base.

FIG. 7 is a schematic plan view illustrating the rotational displacement operation of the work holding unit in the polishing apparatus of the present invention.

FIG. 8 is a side view of a work feed table in the polishing apparatus according to the second embodiment of the present invention.

FIG. 9 is a side view of a work feed table in the polishing apparatus of the third embodiment.

FIG. 10 is a schematic diagram for explaining the rotational displacement operation of the work feed base in the polishing apparatus of the fourth embodiment.

[Explanation of symbols]

1 Grinding Spindle 2 Grinding Tool 2a Buff (Tip) 3 Work Holding Part 4 Mounting Frame 5 Grinding Motor 6 Grinding Machine Main Body 7 Swing Holding Part 8 Swing Drive Shaft 9 Swing Motor 10 Eccentric Air Cylinder 11 Work Feed Base 12 Base frame 12b front frame (fixed part) 13 guide rod 13a one end 13b other end 14a slot 14b long hole 15a guide pin 15b guide pin 16 rack 17 pinion gear a precession tube axis of symmetry axis B work O ₁ before movement Pipe center O ₂ Pipe center after movement P Intermediate point of workpiece pipe axis S ₁ Center of curvature of workpiece before movement S ₂ Center of curvature of workpiece after movement W Work W ₁ One end W ₂ Other end d Moving distance r Radius of curvature of tube axis θ ₁ Opening angle at the center of curvature from one end of the workpiece to the midpoint θ ₂ Rotational displacement angle

Claims (6)

[Claims] 1. A polishing tool is attached to the tip of a polishing main shaft which carries out a precession motion while being rotationally driven, and is capable of advancing and retreating along the direction of the axis of symmetry of this precession motion, and is orthogonal to the moving direction thereof. Holds a workpiece consisting of a 1/4 circular arc tube whose both end surfaces form an angle of 90 degrees to each other in a workpiece holder that can rotate about an axis so that the center of the pipe at one end coincides with the center of rotation of the workpiece holder. Then, in a disposition state in which the surface direction of the one end of the work is orthogonal to the symmetry axis of the precession and the tube center of the one end is on the symmetry axis,
Positioning the polishing tool inside the opening at the one end, rotationally driving and precessing the polishing spindle to bring the polishing tool into sliding contact with the inner surface of the workpiece for polishing, while rotating the workpiece holding portion while moving forward. A polishing method for an inner surface of a curved pipe, characterized in that the polishing tool is advanced to a position approximately in the middle of the inner length of the work. 2. The work holding part is moved at an angle of 20 to 20 while the polishing tool moves from the polishing start position to the midpoint of the inner length of the work.
The method for polishing an inner surface of a curved pipe according to claim 1, wherein the inner surface of the curved pipe is rotationally displaced within a range of 25 degrees. 3. A swinging state in which a main body of a polishing machine having a fixed mounting frame, a polishing spindle having a polishing tool mounted on a front end thereof, and a polishing motor for rotationally driving the polishing spindle allows precession of the polishing spindle. And has a swinging holding portion located on the axis of the polishing main shaft at the rear of the polishing machine main body, and at the rear of the polishing machine main body, there is a swinging drive shaft on the axis of symmetry of the precession and its swinging shaft. A rotary drive motor is installed, and an eccentric air cylinder that holds the swing holding portion in a state of being eccentric from the axis of the drive shaft is provided at the front end of the swing drive shaft. A work feed table that is movable in the perspective direction with respect to the main body is installed in the front, and a work holding section that is rotatable about an axis perpendicular to the moving direction is attached to the work feed table, and the work holding table is held. Part of the work A polishing device for the inner surface of a curved pipe, which is equipped with an interlocking mechanism that rotationally displaces as the feed table moves. 4. An interlocking mechanism for rotatively displacing the work holding part in accordance with the movement of the work feed table, the other end of a guide rod pivotally attached at one end side to the fixed part so as to be rotatable in the rotation surface direction of the work holding part. The polishing device for the inner surface of the curved pipe according to claim 3, wherein the polishing device is configured by pivotally connecting the side and a position deviated from the rotation center of the work holding portion. 5. An interlocking mechanism for rotationally displacing the work holding part according to the movement of the work feed base is provided at a position deviated from the center of rotation of the work holding part and a long hole provided on one side of the fixed part and on the other side. The guide pin is formed by loosely fitting the guide pin.
A polishing device for the inner surface of the curved pipe described. 6. An interlocking mechanism for rotatively displacing the work holding unit according to the movement of the work feed base is fixed to a fixed rack along the moving direction of the work feed base and concentric with the rotation shaft of the work holding unit. The polishing device for the inner surface of a curved pipe according to claim 3, wherein the polishing device is configured by meshing with a pinion gear.