JPH0679569A - Work positioning device - Google Patents

Abstract

PURPOSE:To improve the work positioning accuracy and the service life of a collet in a device to center and position a work by expanding the diameter of the collet inserted to the through-hole of the work. CONSTITUTION:To the through-hole 2 of a work 1 held tentatively to a work holder 3, a center member 5 with the diameter almost same as the through-hole 2 is inserted so as to carry out a tentative centering of the work 1. A positioning head 6 provided at the opposite side of the center member 5 is advanced, and a draw bar 7 of the head 6 is centered to the center member 5 so as to push out the center member 5 from the through-hole 2, and a collet 9 in the diameter contracted condition is inserted in the through-hole 2 instead of the center member 5. The collet 9 is installed between the tips of the draw bar 7 and a flange shaft 8 in the condition to expand and contract its diameter freely. The diameter of the collet 5 inserted to the through-hole 2 is expanded by moving rearward the draw bar 7 with an air cylinder 10, so as to press and engage the collet 5 to the through-hole 2, and the work 1 is positioned and held.

Description

Detailed Description of the Invention

[0001]

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

[0002]

Gears used in automobiles and machine tools are manufactured from various materials through various processes such as gear cutting, shaving, and heat treatment. In such a gear, defects such as tooth flank dents and tooth groove runout may occur during the machining process. Therefore, in the final gear inspection process of manufacture, a highly accurate master gear is engaged from the fixed direction to the gear to be inspected that is positioned and held at a fixed position, and the amount of rocking of the master gear due to rotation of the gear to be inspected The dents on the tooth surface, the presence or absence of runout, and the size measurement are performed.

The gear positioning during 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. 6 to 10.

A gear (hereinafter referred to as a work) (1) shown in FIG. 1 is cylindrical and has a through hole (2) in the center. The work (1) is temporarily held by the work holder (3) as shown in FIGS. 7 and 8, and the collet (21) of the positioning head (20) is inserted into the through hole (2). Then, 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) on top.
Has a semi-circular work receiving surface (4) that fits the outer diameter surface of the.
The outer diameter surface of the work (1) is held substantially concentric 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 work (1) held in place by the work holder (3). They are arranged on the coaxial line so that they can approach and separate from each other.

The positioning head (20) is called a collet arbor and has a headstock (2
Supported by 6). The positioning head (20) includes a drawbar (22), a flange shaft (23) that is axially slidably fitted around the drawbar (22), and a drawbar (22).
And a collet (21) fitted between the tip ends of the flange shaft (23).

As shown in FIG. 7, the collet (21) is a cylinder which has a plurality of slits (28) at equal intervals in the circumferential direction and which can be expanded and contracted in diameter. Inner surfaces of both ends of the collet (21) are conical surfaces that spread 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 collets (21) are fitted between the collet contact surfaces (m) and (n) facing each other. When the collet contact surfaces (m) (n) are separated, the collet (21) is restored (reduced in diameter) by its own elasticity, and when both collet contact surfaces (m) (n) are brought close to each other, both collet contact surfaces (m) The inner surface of the cone of the collet (21) slides with respect to m) and (n), and the diameter of the collet (21) increases.

When the collet (21) is sufficiently reduced in diameter,
That is, the outer diameter when restored is smaller than the inner diameter of the through hole (2) of the work (1). This collet (21) is a work (1)
It is possible to expand to an outside diameter that is slightly larger than the inside diameter of the through hole (2).

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

The push pin (24) is supported by a tailstock (27) that moves back and forth in the axial direction. Push pin (24)
A cylindrical member (3
1) is inserted so that it can slide in the axial direction. Cylindrical members (31)
Is connected to the tailstock (27) via a spring (32).

Work (1) with the work positioning device
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 its work receiving surface (4).

In the state shown in FIG. 7, first, the headstock (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 headstock (26) is advanced until the collet (21) in the reduced diameter position is located in the through hole (2) of the work (1). ) Contacts the side surface of the work (1).

Next, the tailstock (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 positioned away from the draw bar (22) of the positioning head (20).

In the state shown in FIG. 9, the pressing pin (24) advances, and the conical sharpened portion (24 ') at the tip of the pressing pin (24) moves to the drawbar (2).
2) It projects into a conical pin receiver (25) formed in the center of the tip surface of 2), and the pressing pin (24) and draw bar (22) are centered. The pressing pin (24) retracts the drawbar (22) against the spring force of the spring (29) from the time when the sharpened portion (24 ') is fitted into 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), the diameter of the collet (21) is expanded, and the state shown in FIG. 10 is obtained.

By expanding the diameter of the collet (21), the collet (21)
The outer periphery of the work is pressed into engagement with the through hole (2) of the work (1), and the work (1) is centered coaxially with 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, a master gear (33) for inspecting the work (1) approaches and meshes with the work (1) from a fixed direction, as shown by the chain line in FIG. The work (1) rotates, and this rotation causes the master gear (33) to rotate dependently, and the tooth surface dents and other marks on the work (1) are inspected.

When the inspection is completed, the master gear (33) separates from the work (1). Next, the pressing pin (24) retracts, and in this retracting, the draw bar (22) advances by the spring force of the spring (29), and the draw bar (22) and the flange shaft (23) collet contact surface (m) ( n) separates and the collet (21) restores (reduces) to the original outer diameter. After that, the tailstock (27) and the headstock (26) are retracted in order, the work (1) is held again by the work holder (3), and then taken out to the outside.

[0018]

The outer diameter of the work (1) has a large dimensional tolerance, and the through hole (2) of the work (1) positioned and held by the work receiving surface (4) of the work holder (3).
The amount of misalignment between the center of the and the center of the positioning head (20) may increase. Therefore, the work holder (3)
The outer diameter of the collet (21) when it is inserted into the through hole (2) of the work (1) held by is set sufficiently smaller than the inner diameter of the through hole (2) in anticipation of the misalignment. There is a need. That is, the inner diameter of the through hole (2) and the collet (2
If the outer diameters of 1) are about the same, when the collet (21) is inserted into the through hole (2), the collet (21) is misaligned as described above.
Since the edge of the collet may collide with the edge of the through hole (2), the outer diameter of the collet (21) at the time of restoration (reduction) should be sufficiently small.

Therefore, it is necessary for the collet (21) to have a large difference between the outer diameter when the diameter is reduced and the outer diameter when the diameter is increased, and the amount of deformation of the diameter reduction is increased, so that the diameter expansion is performed. However, there is a problem that the accuracy of positioning becomes poor and the positioning accuracy of the work (1) becomes poor. Further, the collet (21) has a problem that it is easily cracked due to a large amount of deformation due to 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 expand the diameter of the collet. Although (21) was restored (reduced in diameter), the draw bar (22) that had bitten into the inner diameter of the collet (21) did not move forward smoothly at this time, and the collet (21) sometimes did not reduce in diameter. Therefore, even after the inspection of the work (1) is completed, the collet (21) whose diameter has been expanded to the work (1) is pressed into engagement and does not separate, and there is a possibility that the operation of the next work inspection cannot be performed.

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

[0022]

According to the present invention, there is provided a work holder for holding a work having a through hole serving as a positioning reference in a fixed position, and one side of the through hole of the work held by the work holder. , Is arranged so as to be able to approach and separate from the through hole of the work, and is inserted while centering the work in the through hole of the work at the time of forward movement, and is held by the work holder and the center member that holds the work instead of the work holder. A drawbar and a drawbar that are arranged on one side of the through hole of the work so that they can approach and separate from the through hole of the work and are centered by a center member that holds the work during forward movement and push the center member out of the through hole of the work. Flange shaft mounted on the outer periphery of the drawbar so as to be slidable in the axial direction, and fitted between the drawbar and the tip of the flange shaft, and the axial direction of the drawbar and the flange shaft And a positioning head having a collet whose diameter is expanded and reduced by relative movement of the collet, the collet of the positioning head being inserted into the through hole of the work while the work is centered by the center member. The object is achieved by expanding the diameter of the workpiece and positioning the workpiece.

Further, according to the present invention, in order to achieve the object of stabilizing the expansion and contraction operations of the collet, the relative movement of the draw bar and the flange shaft for expanding and contracting the collet of the positioning head is performed by the air cylinder. It is characterized by

[0024]

Since the center member is inserted into the through hole of the work for centering and the collet in the reduced diameter state of the positioning head is inserted into the through hole of the work in the centered state,
The maximum misalignment amount between the through hole of the work and the collet inserted therethrough 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 made small. Therefore, as the collet, a highly accurate and long-life collet with a small amount of deformation by diameter reduction and expansion can be applied.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIG.
It will be described with reference to FIG. The same or corresponding portions of the workpiece positioning apparatus shown in the embodiment of FIG. 6 as those of FIG. 6 are designated by the same reference numerals and description thereof will be omitted.

The work positioning device shown in FIG. 1 has a center member (5) and a tailstock (11) on one side of a through hole (2) of a work (1) held at a fixed position by a work holder (3). ) Is arranged, and a positioning head (6) and a headstock (12) are arranged on one side opposite to the through hole (2). The center member (5) is supported by the 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 that they can approach and separate from each other.

The center member (5) is a cylinder having an outer diameter slightly smaller than the inner diameter of the through hole (2) of the work (1), and a conical taper surface (13) is formed on the outer circumference of the tip end surface. A conical centering pin (14) is provided at the center of the projection. 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 tighter than the conventional dimensional tolerance between the outer diameter of the work (1) and the work holder (3).

The work (1) is attached to the outer periphery of the center member (5).
A cylindrical member (15) for appropriately pressing the side surface of the is mounted so as to be slidable in the axial direction. The cylindrical member (15) has a tailstock (1
It is connected to 1) via a spring (16).

The positioning head (6) has a drawbar (7).
A flange shaft (8) is axially slidably fitted on the outer periphery of the collet contact surface (m) (m) (which is formed on the outer periphery of the drawbar (7) and the front end of the flange shaft (8) and faces a substantially V shape. The collet (9) is fitted between n). The collet (9) opens and closes by expanding and contracting the diameter when the collet contact surfaces (m) and (n) move toward and away from each other.

The outer diameter of the collet (9) when the diameter is reduced is set to be slightly smaller than the inner diameter of the through hole (2) of the work (1).
Further, 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 the piston rod of the air cylinder (10) fixed to the headstock (12). The draw bar (7) and the flange shaft (8) are moved relative to each other in the front and rear by the air cylinder (10) to expand and contract the collet (9).

As shown in FIG. 2, a conical centering hole (18) is formed in the center of the front end surface of the draw bar (7). Align the centering pin (1) of the center member (5) with this centering hole (18).
The center member (5) and the positioning head (6) are centered by inserting the (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 in place by the work holder (3), the tailstock (11) first advances. With this forward movement, as shown in FIG. 3, the tip end of the cylindrical member (15) abuts against the side surface of the work (1) and stops, and the center member (5) further advances and the through hole ( Inserted in 2) and stop. The cylindrical member (15) compresses the spring (16) and elastically presses the work (1).

When there is some 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) is advanced. The edge of the through hole (2) of the work (1) slides on the tapered surface (13) of the workpiece (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 centered on the center member (5). The center member (5) replaces the work holder (3) and the work (1)
Hold in place.

Next, the headstock (12) advances.
At this time, the collet (9) of the positioning head (6) is in a reduced diameter state. When the headstock (12) advances, the centering hole (18) at the tip of the drawbar (7) of the positioning head (6) is first fitted into the centering pin (14) of the center member (5), and the centering member (5) is inserted. After the centering of (5) and 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 instead, the through hole (2) is reduced in diameter. The collet (9) is inserted. Before and after this insertion, the ring member (17) of the positioning head (6) is attached to the work (1).
The headstock (12) is stopped from being advanced by being pressed by the side surface of the.

When the drawbar (7) is retracted by the air cylinder (10) in the state of FIG. 4, as shown in FIG. 5, the collet contact surfaces (m) (n) of the drawbar (7) and the flange shaft (8) (n) ) Approached, collet (9) expanded in diameter,
The outer circumference of the collet (9) is pressed and engaged with the through hole (2) of the work (1). At this stage, the work (1) is centered on the positioning head (6) and positioned and held.

As described above, the through hole (2) of the work (1)
Before inserting the collet (9) into the center of the work (1) with the center member (5), the through hole (2)
And the collet (9) will be 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 a sufficiently small value, the collet (9) in the through hole (2) will always be smooth and secure. 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 between when the collet (9) is reduced and when it is expanded can be reduced.
As a result, the accuracy of the collet (9) when the diameter is reduced and when it is expanded is improved, the positioning accuracy of the work (1) is improved, and the rate at which the collet (9) is cracked 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) is brought into close contact with the work (1) from a fixed direction, Inspection of the dents on the tooth surface of the work (1) is performed. When this inspection is completed, the master gear (33) separates from the work (1).

Thereafter, the tailstock (11) is retracted and the drawbar (7) of the positioning head (6) is advanced by the air cylinder (10) to reduce the diameter of the collet (9). Since the drawbar (7) is forcibly advanced by the air cylinder (10), even if the drawbar (7) bites strongly into the inner diameter of the collet (9), the collet (9) contracts due to the spring force of the spring. More reliable than diameter operation. Next, the headstock (12) retracts and the positioning head (6) separates from the work (1).

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

[0043]

According to the present invention, the center member is inserted into the through hole of the work, the work is temporarily centered and positioned, and the collet in the reduced diameter state of the positioning head is inserted into the through hole of the work. 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, and as a result, As the collet of the positioning head, a highly accurate and long-life collet having a small amount of deformation due to diameter reduction and expansion can be used, and a long-life workpiece positioning device for highly accurately positioning a workpiece can be provided.

Further, the diameter expansion of the collet of the positioning head,
Since the collet is opened and closed with the air cylinder, the collet opening and closing operation is ensured, and a highly reliable work positioning device can be provided.

[Brief description of drawings]

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

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

FIG. 3 is a partially enlarged front view of the apparatus shown in FIG.

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

FIG. 5 is a partially enlarged front view of the apparatus of 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 the work positioning operation.

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

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

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

Claims (2)

[Claims] 1. A work holder for holding a work having a through hole serving as a positioning reference at a fixed position, and one side of the through hole of the work held by the work holder,
It is arranged so that it can move toward and away from the through hole of the work, and is inserted while centering the work in the through hole of the work when moving forward, and the center member that holds the work instead of the work holder, and the work held by the work holder A drawbar and a drawbar that are arranged on one side of the through hole of the work piece so as to be able to approach and separate from the through hole of the work, and are centered with the center member that holds the work and push the center member out of the through hole of the work when moving forward. The outer diameter of the flange shaft is slidably mounted on the outer periphery of the shaft, and it is fitted between the drawbar and the tip of the flange shaft, and the outer diameter expands and contracts due to the relative axial movement of the drawbar and the flange shaft. The positioning head has a collet, and the outer diameter of the positioning head when the collet diameter is reduced is smaller than the inner diameter of the through hole of the workpiece. Insert the positioning head with the collet in the reduced diameter state into the through hole of the work piece, push the center member out from the through hole, and instead with the collet in the reduced diameter state, expand the collet with the drawbar and flange shaft. A work positioning device characterized by being press-engaged with a through hole of a work. 2. The air cylinder is used as a drive source for relative movement between the draw bar and the flange shaft for expanding and contracting the collet of the positioning head.
The work positioning device described.