JP3000538B2 - Work positioning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work positioning apparatus having a through hole serving as a positioning reference. More specifically, the present invention relates to a method of inserting a collet to be expanded and reduced in diameter into a through hole of the work in a reduced diameter state. The present invention relates to a work positioning apparatus for centering and positioning a work by expanding a collet and pressing and engaging the collet into a through hole of the work.

[0002]

2. Description of the Related Art Gears used in automobiles and machine tools are manufactured from raw materials through various processes such as gear cutting, shaving and heat treatment. Such gears may have defects such as tooth dents and tooth groove runout in the machining process. Therefore, in the final gear inspection process, a highly accurate master gear is meshed with the inspected gear positioned and held in a fixed position from a fixed direction, and the amount of swing of the master gear caused by the rotation of the inspected gear is used to determine the gear of the inspected gear. We perform dents on the tooth surface, presence or absence of tooth groove runout, and measurement of size.

[0003] The gear positioning at the time of the gear inspection is performed with reference to a through hole formed in the center of the gear. A conventional example of such a gear positioning device will be described with reference to FIGS.

A gear (hereinafter referred to as a work) (1) shown in FIG. 1 is cylindrical and has a through hole (2) at the center. The collet (21) of the positioning head (20) is inserted into the through hole (2) while the work (1) is temporarily held by the work holder (3) as shown in FIGS. Thereafter, as shown in FIGS. 6 and 10, the collet (21) is expanded in diameter by the positioning head (20), and the work (1) is positioned and held.

The work holder (3) has a work (1)
It has a substantially semicircular work receiving surface (4) that fits the outer diameter surface of.
The outer surface of the work (1) is held substantially concentrically with the work receiving surface (4). A positioning head (20) and a pressing pin (24) for expanding the collet (21) of the positioning head (20) are provided on both sides of the through hole (2) of the workpiece (1) held in place by the workpiece holder (3). They are arranged on a coaxial line so that they can approach and move away from each other.

[0006] The positioning head (20) is called a collet arbor, and a headstock (2) that moves back and forth in its axial direction.
Supported by 6). The positioning head (20) is composed of a draw bar (22), a flange shaft (23) fitted to the outer periphery of the draw bar (22) so as to be slidable in the axial direction, and a draw bar (22).
And a collet (21) fitted between the distal ends of the flange shaft (23).

As shown in FIG. 7, the collet (21) is a cylinder having a plurality of slits (28) at equal intervals in the circumferential direction and capable of increasing and decreasing the diameter. The inner surface of both ends of the collet (21) is a conical surface extending outward. The conical collet contact surface (m) formed on the outer periphery of the tip of the draw bar (22) and the conical collet contact surface (n) formed on the outer periphery of the tip of the flange shaft (23) are substantially V-shaped. The collet (21) is fitted between the collet contact surfaces (m) and (n) so as to face each other. When the collet contact surfaces (m) and (n) are separated from each other, the collet (21) is restored (reduced in diameter) by its own elasticity, and when the collet contact surfaces (m) and (n) are approached, the collet contact surfaces ( m) The inner surface of the cone of the collet (21) slides relative to (n), and the collet (21) expands in diameter.

When the collet (21) is sufficiently reduced in diameter,
That is, the outer diameter at the time of restoration is smaller than the inner diameter of the through hole (2) of the work (1). This collet (21) is the work (1)
The diameter can be expanded to an outer diameter slightly larger than the inner diameter of the through hole (2).

The flange shaft (23) is fixed to the headstock (26), and a spring (29) is compression-mounted between the flange shaft (23) and the base end of the draw bar (22). A ring member (30) for appropriately pressing the work (1) is fixedly arranged at the tip of the flange shaft (23).

The pressing pin (24) is supported by a tailstock (27) that moves back and forth in the axial direction. Press pin (24)
A cylindrical member (3) that appropriately presses the work (1)
1) is inserted so that it can slide in the axial direction. Cylindrical member (31)
Is connected to the tail stock (27) via a spring (32).

[0011] The work (1)
Are positioned in the following order: When the work (1) is supplied to the fixed position for positioning, the work holder (3)
Holds the work (1) on the work receiving surface (4).

In the state of FIG. 7, first, the head stock (26)
Moves forward. At this time, the collet (21) of the positioning head (20) is in a restored (reduced diameter) state. As shown in FIG. 9, the head stock (26) is advanced until the collet (21) in the reduced state is positioned in the through hole (2) of the work (1). ) Contacts the side of the work (1).

Next, the tail stock (27) moves forward,
The tip of the cylindrical member (31) presses the side surface of the work (1) with the elasticity of the spring (32). At this time, as shown in FIG. 9, the pressing pin (24) is at a position separated from the draw bar (22) of the positioning head (20).

In the state shown in FIG. 9, the pressing pin (24) moves forward, and the conical pointed portion (24 ') at the tip of the pressing pin (24) is moved to the draw bar (2).
2), it penetrates into a conical pin receiver (25) formed at the center of the tip surface, and the pressing pin (24) and the drawbar (22) are centered. The pressing pin (24) retreats the draw bar (22) against the spring force of the spring (29) from the time when the sharp portion (24 ') is fitted to the pin receiver (25). By this retreat, the collet contact surface (n) of the draw bar (22) approaches the collet contact surface (n) of the flange shaft (23), and the collet (21) is expanded in diameter, as shown in FIG.

[0015] The diameter of the collet (21) is increased to make the collet (21) larger.
Is pressed into engagement with the through hole (2) of the work (1), and the work (1) is centered on the positioning head (20). The expanded state of the collet (21) is maintained as it is,
The work (1) is positioned and held by the positioning head (20).

When the positioning and holding of the work (1) is completed, the master gear (33) for inspecting the work (1) approaches and meshes with the work (1) from a fixed direction as shown by a chain line in FIG. The work (1) rotates, and the master gear (33) rotates dependently by this rotation, and the work (1) is inspected for tooth dents and the like.

When the inspection is completed, the master gear (33) separates from the work (1). Next, the pressing pin (24) is retracted, and with this retraction, the draw bar (22) moves forward by the spring force of the spring (29), and the collet contact surface (m) (m) of the draw bar (22) and the flange shaft (23) n) is separated and the collet (21) is restored (reduced in diameter) to the original outer diameter. Thereafter, the tail stock (27) and the head stock (26) retreat in order, and the work (1) is again held by the work holder (3), and then is taken out.

[0018]

The outside diameter of the work (1) has a large dimensional tolerance, and the through hole (2) of the work (1) positioned and held on the work receiving surface (4) of the work holder (3).
And the center of the positioning head (20) may be large. Therefore, work holder (3)
The outer diameter of the collet (21) when it is inserted through the through hole (2) of the work (1) held in the step (1) is made sufficiently smaller than the inner diameter of the through hole (2) in anticipation of the above-mentioned misalignment. There is a need. In other words, the inner diameter of the through hole (2) and the collet (2
If the outer diameter of 1) is substantially the same, when the collet (21) is inserted into the through hole (2), the collet (21)
May collide with the edge of the through hole (2), so that the outer diameter of the collet (21) at the time of restoration (diameter reduction) must be sufficiently small.

For this reason, the collet (21) is required to have a large difference between the outer diameter at the time of diameter reduction and the outer diameter at the time of diameter expansion. There was a problem that the accuracy at the time was deteriorated and the positioning accuracy of the work (1) was deteriorated. Further, the collet (21) has a problem that the collet (21) is liable to be broken due to a large amount of deformation in the diameter reduction and expansion, and has a short life.

After the inspection of the work (1) is completed, the pressing pin (24) is retracted, and the draw bar (22) of the positioning head (20) is advanced by the spring force of the spring (29) to increase the diameter of the collet. (21) is restored (reduced diameter), but at this time, the draw bar (22) that has cut into the inner diameter of the collet (21) does not advance smoothly, and the collet (21) may not be reduced in diameter. Therefore, even after the inspection of the work (1) is completed, there is a possibility that the collet (21) whose diameter has been expanded on the work (1) does not come off by being pressed and engaged, and the operation of the next work inspection cannot be performed.

An object of the present invention is to improve the positioning accuracy of a work by sufficiently reducing the amount of deformation of a collet which is inserted into a through-hole of a work and expanded in diameter, and has high reliability, long life, and stable operation. An object of the present invention is to provide a work positioning device.

[0022]

SUMMARY OF THE INVENTION According to the present invention, there is provided a work holder for holding a work provided with a through hole serving as a reference for positioning at a fixed position, and a work holding tool provided on one side of the through hole of the work held by the work holder. , Are arranged so as to be able to approach and separate from the through hole of the work, are inserted while centering the work in the through hole of the work at the time of forward movement, and are held by the work holder and a center member for holding the work instead of the work holder. A draw bar, which is arranged on the other side of the through hole of the work so as to be able to approach and separate from the through hole of the work, is centered on a center member that holds the work at the time of forward movement, and pushes the center member out of the through hole of the work, and a draw bar. A flange shaft slidably mounted on the outer periphery of the shaft, and a fitting between the draw bar and the distal end of the flange shaft. And a positioning head having a collet whose diameter is increased and decreased by the relative movement of the positioning head, wherein the collet of the positioning head is inserted through the through hole of the work while the work is centered by the center member, and The above object is achieved by enlarging the diameter and positioning the work.

Further, in order to achieve the object of stabilizing the operation of expanding and reducing the diameter of the collet according to the present invention, the relative movement between the draw bar and the flange shaft for expanding and reducing the diameter of the collet of the positioning head is performed by an air cylinder. It is characterized by the following.

[0024]

In order to insert the center member into the through hole of the work and to align the center member, and to insert the collet with the reduced diameter of the positioning head into the through hole of the work in the centered state,
The maximum misalignment between the through hole of the work and the collet inserted therein can be reduced, and the difference between the inner diameter of the through hole of the work and the outer diameter of the reduced collet can be reduced. Therefore, a high-precision and long-life collet with a small amount of deformation due to diameter reduction and expansion can be applied.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. In the work positioning device shown in the embodiment of the same figure, the same or corresponding parts as those of the device of FIG.

The work positioning device shown in FIG. 1 has a center member (5) and a tail stock (11) at one side of a through hole (2) of a work (1) held at a fixed position by a work holder (3). ), And a positioning head (6) and a head stock (12) are arranged on one side opposite to the through hole (2). The center member (5) is supported by a tailstock (11) that moves back and forth in the axial direction. The positioning head (6) is supported by a headstock (12) that moves back and forth in the axial direction. The center member (5) and the positioning head (6) are arranged on a coaxial line so as to be able to approach and separate from each other.

The center member (5) is a column having an outer diameter slightly smaller than the inner diameter of the through hole (2) of the work (1), and has a conical tapered surface (13) formed on the outer periphery of the tip portion. A conical centering pin (14) protrudes from the center. The work center member (5) is centered on the work (1) by being inserted into the through hole (2) of the work (1), but the outer diameter of the center member (5) and the work (1) The dimensional tolerance with the inner diameter is
It is set to be tighter than the dimensional tolerance between the conventional work (1) outer diameter and the work holder (3).

On the outer periphery of the center member (5), a work (1)
A cylindrical member (15) that appropriately presses the side surface of is mounted slidably in the axial direction. The cylindrical member (15) is tailstock (1
It is connected to 1) via a spring (16).

The positioning head (6) includes a draw bar (7)
A flange shaft (8) is axially slidably fitted on the outer periphery of the collet, and a collet contact surface (m) (m) formed on the outer periphery of each end of the draw bar (7) and the flange shaft (8) and facing a substantially V-shape. A collet (9) is fitted between n). The collet (9) opens and closes the diameter of the collet (9) by the movement of the collet contact surfaces (m) and (n) toward and away from each other.

The outer diameter of the collet (9) when the diameter is reduced is set slightly smaller than the inner diameter of the through hole (2) of the work (1).
Also, the collet (9) can be expanded to an outer diameter slightly larger than the inner diameter of the through hole (2) of the work (1).

The flange shaft (8) is fixed to the headstock (12), and a ring member (17) for appropriately pressing the side surface of the work (1) is fixed to the tip of the flange shaft (8). The drawbar (7) is connected to a piston rod of an air cylinder (10) fixed to the headstock (12). The relative movement of the draw bar (7) and the flange shaft (8) before and after is performed by the air cylinder (10), and the diameter of the collet (9) is expanded and reduced.

As shown in FIG. 2, a conical centering hole (18) is formed at the center of the distal end surface of the draw bar (7). The centering pin (1) of the center member (5) is inserted into the centering hole (18).
The centering of the center member (5) and the positioning head (6) is performed by inserting 4).

The work positioning operation according to the above embodiment will be described.

As shown in FIG. 2, when the work (1) is temporarily held at a fixed position by the work holder (3), the tail stock (11) first moves forward. By this advance, as shown in FIG. 3, the tip of the cylindrical member (15) comes into contact with the side surface of the work (1) and stops, and the center member (5) further advances and the through-hole ( Stops after being inserted in 2). The cylindrical member (15) compresses the spring (16) to repress the work (1).

When there is a slight misalignment between the center of the through hole (2) of the work (1) held by the work holder (3) and the center of the center member (5), the center member (5) which moves forward The edge of the through hole (2) of the work (1) slides on the tapered surface (13) of the work (1), and the center of the through hole (2) moves to the center of the center member (5). When the outer periphery of the center member (5) is inserted into the through hole (2), the work (1) is held in a state where the work (1) is centered on the center member (5). The center member (5) replaces the work holder (3) with the work (1)
Is held in place.

Next, the head stock (12) moves forward.
At this time, the collet (9) of the positioning head (6) is in a reduced diameter state. When the head stock (12) advances, first, the centering hole (18) at the tip of the draw bar (7) of the positioning head (6) is inserted into the centering pin (14) of the center member (5). After the centering of the positioning head (6) with the positioning head (6) is performed, the draw bar (7) presses the center member (5).

Then, as shown in FIG. 4, the center member (5) is pushed out from the through hole (2) of the work (1) by the advance of the draw bar (7), and the diameter is reduced to the through hole (2) instead. Collet (9) is inserted. Before and after this insertion, the ring member (17) of the positioning head (6) becomes the work (1).
And the forward movement of the headstock (12) stops.

When the draw bar (7) is retracted by the air cylinder (10) in the state of FIG. 4, as shown in FIG. 5, the draw bar (7) and the collet contact surface (m) (n) of the flange shaft (8) ) Approaches and the collet (9) expands,
The outer periphery of the collet (9) is pressed into the through hole (2) of the work (1). At this stage, the work (1) is centered on the positioning head (6) and is positioned and held.

As described above, the through hole (2) of the work (1)
Before inserting the collet (9) into the center, the work (1) is centered with the center member (5), so that the through hole (2)
And collet (9) are inserted without misalignment. Therefore, even if the difference between the outer diameter of the collet (9) in the reduced diameter state and the inner diameter of the through hole (2) is set to be sufficiently small, the collet (9) is always smoothly and reliably inserted into the through hole (2). It is inserted. Also, by reducing the difference between the outer diameter of the collet (9) in the reduced diameter state and the inner diameter of the through hole (2), the amount of change when the collet (9) is reduced in diameter and when it is expanded can be reduced.
As a result, the accuracy of the collet (9) when the diameter of the collet (9) is reduced and the diameter of the collet (9) is improved, the positioning accuracy of the work (1) is improved, and the rate at which the collet (9) is broken is reduced.

Next, the state shown in FIG. 5 is maintained, and as shown by the chain line in FIG. 1, the master gear (33) for inspecting the work (1) approaches and meshes with the work (1) from a fixed direction. The work (1) is inspected for dents on the tooth surface. When this inspection is completed, the master gear (33) separates from the work (1).

Thereafter, the tail stock (11) is retracted, and the draw bar (7) of the positioning head (6) is advanced by the air cylinder (10) to reduce the diameter of the collet (9). The drawbar (7) is forcibly advanced by the air cylinder (10), so even if the drawbar (7) bites into the inner diameter of the collet (9), the collapsing operation of the collet (9) is reduced by the spring force of the spring. More reliable than radial operation. Next, the head stock (12) retreats, and the positioning head (6) separates from the work (1).

The work to be positioned in the present invention is not limited to a gear, but it can be effectively applied to any work having a through hole serving as a positioning reference.

[0043]

According to the present invention, the center member is inserted into the through hole of the work, and the collet in the reduced diameter state of the positioning head is inserted into the through hole of the work in a state where the work is pre-centered and positioned. Therefore, the collet with almost no misalignment is inserted into the through hole of the work, and the difference between the inner diameter of the through hole of the work and the outer diameter of the reduced collet can be sufficiently reduced. As a result, As the collet of the positioning head, a high-precision and long-life collet with a small amount of deformation due to diameter reduction and expansion can be used, and a long-life work positioning device for positioning the work with high accuracy can be provided.

In addition, the diameter of the collet of the positioning head is increased,
By performing the opening and closing of the reduced diameter by the air cylinder, the opening and closing operation of the collet is ensured, and a highly reliable work positioning device can be provided.

[Brief description of the drawings]

FIG. 1 is a front view including a partial cross section of a main part showing an embodiment of the present invention.

FIG. 2 is a partially enlarged front view of the apparatus in FIG. 1 before a work positioning operation.

FIG. 3 is a partially enlarged front view of the apparatus of FIG. 1 when the workpiece is centered and held.

FIG. 4 is a partially enlarged front view of the apparatus of FIG. 1 immediately before positioning of a workpiece.

5 is a partially enlarged front view of the apparatus shown in FIG. 1 when positioning a workpiece.

FIG. 6 is a front view including a partial cross section of a main part of a conventional work positioning device.

FIG. 7 is a partially enlarged front view of the apparatus shown in FIG. 6 before a work positioning operation.

FIG. 8 is a side view of the work and its holder in FIG. 7;

9 is a partially enlarged front view of the apparatus of FIG. 6 immediately before positioning of a workpiece.

10 is a partially enlarged front view of the apparatus shown in FIG. 6 when positioning a workpiece.

[Explanation of symbols]

 1 Work 2 Through hole 3 Work holder 5 Center member 6 Positioning head 7 Drawbar 8 Flange shaft 9 Collet 10 Air cylinder

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23Q 3/18

Claims (2)

(57) [Claims] 1. A work holder for holding a work provided with a through hole serving as a positioning reference at a fixed position, and a work holding tool provided on one side of the through hole of the work held by the work holder.
A center member that is arranged so as to be able to approach and separate from the through hole of the work, is inserted while centering the work in the through hole of the work when moving forward, and holds the work in place of the work holder, and the work held by the work holder A drawbar, which is arranged on one side of the other through hole so as to be able to approach and separate from the through hole of the work, and which is centered with a center member for holding the work and pushes the center member out of the through hole of the work during forward movement; and A flange shaft that is slidably mounted on the outer periphery of the shaft, and is fitted between the drawbar and the tip of the flange shaft, and the outer diameter is increased and decreased by the relative movement in the axial direction between the drawbar and the flange shaft. The collet of the positioning head has a smaller outer diameter than the inner diameter of the through hole of the work. Insert the positioning head with the reduced diameter collet into the through hole of the work and push out the center member from the through hole.Instead of inserting the reduced diameter collet, expand the collet with the draw bar and the flange shaft. A work positioning device characterized by being pressed into engagement with a through hole of a work. 2. A driving source for a relative movement between a draw bar and a flange shaft for expanding and reducing the diameter of a collet of a positioning head is an air cylinder.
Work positioning device according to the above.