JP3044720B2 - Work positioning method using locate pin - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work positioning method suitable for use when a plurality of locating pins are fitted into a plurality of locating holes of a work to position the work. It is.

(Prior Art) In the case described above, for example, a floor main carried into a body assembly stage of a body assembly line by a transport device such as a shuttle bar is positioned on the stage by lowering the shuttle bar or raising the locate pin, Conventionally, in such a case, the locating pins 2 are fitted into the locating holes provided in the square portion of the floor main 1 as shown in FIG. 4 (a). Especially, four locating pins 2
Then, the floor main 1 is positioned.

However, since the floor main 1 is assembled from a plurality of parts, the location accuracy of the locate holes varies, and when positioning such a floor main, the rigidity of the gauge post that supports the locate pin is usually not so high. Therefore, even if the outer diameter of the locating pin is extremely close to the inner diameter of the locating hole, if a part of the conical tip of each locating pin is inserted into the locating hole, the conical tip surface of the locating hole becomes the inner peripheral surface of the locating hole. When the gauge post is deflected and the gauge post bends, the locate pins are slightly displaced on average, and each locate pin follows the location of the locate hole, so all the locate pins are fitted into the locate holes and the floor main is accurately positioned. Can be positioned.

(Problems to be Solved by the Invention) In recent years, in response to a demand for mixed production of a plurality of models, in order to position the floor mains of the plurality of models with a common locating pin, the locating pins are each supported by a wrist of a robot. In some cases, the location can be changed.In such a case, since the support rigidity of the locate pin is much higher than that of the gauge post, a small displacement of the locate pin following the location of the locate hole does not occur. It cannot fit into the locate hole.

For this reason, in the case described above, conventionally, the outer diameter of each locating pin is set to a degree that can correspond to the variation in the positional accuracy of the locating hole of the floor main, for example, the inner diameter of the locating hole −0.5 m.
m, or the number of locating pins was reduced to narrow the range of variations in the location of the locating hole as shown in FIGS. 4 (b) to (e). Decline was inevitable.

The present invention provides a work positioning method that advantageously solves the above-described problems.

(Means for Solving the Problems) According to a work positioning method of the present invention, a plurality of locating pins are fitted into a plurality of locating holes of a single elastically deformable work having positional accuracy variations, thereby positioning the work. In doing so, in the method according to claim 1, the locating pin is displaced with respect to a support member that supports the locating pin in a floating manner, and each of the locating pins is fitted into the locating pin hole. Then, the work is elastically deformed between the locating pins. 3. The method according to claim 2, wherein the locating pins are forcibly returned to their proper positions on the supporting member and then fixed to the supporting members. The method according to claim 2, wherein the locating pin is sufficiently smaller than the inner diameter of the locating hole. After fitting the locate pins reduced in outer diameter into the locate holes, the work is moved to the locate holes. While elastically deformed between the pins substantially equal as diameter the outer diameter of those locating pin to the inside diameter of the locator hole, it is characterized in that fixed in its expanded state.

According to this method, in the method according to the first aspect, particularly, for a work that can be elastically deformed, a guide cone or the like is provided at a tip of a locating pin or a locating hole of the work to achieve floating. After displacing the supported locate pin in accordance with the location of the locate hole and inserting it into the locate hole,
Since the locate pin is forcibly returned to the regular position on the support member while elastically deforming the work between the locate pins, even if the rigidity of the support member is high, each locate pin must be securely placed in the locate hole with uneven position accuracy. The work can be reliably positioned by being fitted, and since the locating pin returned to the normal position is fixed to the support member, the work can be accurately positioned even after the return.

According to the method of claim 2, particularly, for a work which can be elastically deformed, the diameter of the locate pin is reduced, and after the work is elastically deformed between the locate pins, the diameter of the locate pin is expanded. Even with the method, even if the rigidity of the support member is high, each locating pin can be securely fitted into the locating hole with uneven position accuracy to position the work reliably, and the locating pin with the increased diameter can be used in that state. Since the workpiece is fixed, the workpiece can be accurately positioned even after the diameter is increased.

Embodiment An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view showing a floor main positioning device in a vehicle body assembling stage of a vehicle body assembling line to which an embodiment of a work positioning method using a locating pin according to the present invention is applied. Then, the floor main 1 as a work carried into the stage is picked up from the shuttle bar 3 by raising the work base 4 having the locating pins 2 and then positioned on the stage so as to be positioned on the wrist. Cartesian positioning robots 5 supported by the robot
Is provided below the square portion of the loading position of the floor main 1 on the stage.

As shown in FIG. 2, each of the positioning robots 5 moves the work base 4 on which the locate pins 2 are erected, in the vertical direction, that is, in the Z-axis direction (see FIG. (Indicated by middle arrow Z)
And the horizontal Y-axis direction (direction perpendicular to the paper plane in the figure) which is the direction in which the shuttle bar 3 extends and which is also the front-rear direction of the vehicle body to be assembled. It can be moved to any position in the horizontal X-axis direction (indicated by the arrow X in the figure) which is also the direction.

Each of the positioning robots 5 here supports the work base 4 in a floating manner via a floating mechanism 6 on a hand mounting table 5a as a wrist as shown in FIG. Mechanism 6
Urges the movable block 9 slidably fitted in the direction of arrow A in the rectangular parallelepiped concave portion 8 provided on the upper part of the casing 7 to return to the center position by a weak spring 10. The work base 4 is provided with a movable block having a configuration in which a plug 11 that can be fitted into the hole is movable forward and backward by an air cylinder 12 with respect to a frustoconical hole 9a provided in the center of the work base. 9 is fixed.

In such a floor main positioning device, the floor main 1 in which the locate hole 1a is displaced in the X-axis direction with respect to the normal locate hole position when the floor main is positioned at the regular position of the stage is described below. Position with.

That is, here, first, based on the operation of each positioning robot 5, each work base 4 is moved to the locating pin 2 at the Z-axis direction position below the path that does not interfere with the transport path of the floor main 1 by the shuttle bar 3. And, when the floor main 1 is located at the predetermined carry-in position, the regular center position of each of the locate holes 1a and the center position of the locate pin 2 are located at the X-axis and Y-axis direction positions where the center position is aligned vertically.
When the shuttle bar 3 carries the floor main 1 to the carry-in position, the work bases 4
After the upper surface on which the locating pin is erected contacts the lower surface of the floor main 1 provided with the locating hole 1a, the floor main 1 is lifted from the shuttle bar 3 and rises until it is located at a predetermined positioning position in the Z-axis direction. Let it.

When the work base 4 rises, the locate pin 2 naturally rises toward the locate hole 1a.
Since the floating mechanism 6 pulls the plug 11 out of the hole 9a to keep the movable block 9 in a floating state, when a part of the tapered tip of each locate pin 2 comes into contact with the inner peripheral surface of the locate hole 1a, the floating pin 6 The truncated cone-shaped tip surface is pressed by the inner peripheral surface of the locate hole 1a, and is slightly displaced in accordance with the position of the locate hole and fitted into the locate hole 1a. The upper surface of the work base 4 as shown and the lower surface of the floor main 1 provided with the locate hole 1a are brought into contact with each other, and the floor main 1 can be lifted by the work base 4.

Thereafter, the plug 11 is pushed into the hole 9a by the operation of the air cylinder 12, and the movable block 9 and the locating pin 2 are fixed to the hand mount 5a of the robot 5 by closely fitting them.

Here, the pushing of the plug 11 into the hole 9a is performed according to the location hole.
Since the center positions of the hole 9a and the plug 11 are also shifted from each other due to the position shift of 1a, the inner peripheral surface of the hole 9a is pressed laterally by the frusto-conical tip surface of the plug 11. This is performed by slightly moving the movable block 9, and the fine movement of the locating pin 2 and the locating hole 1a due to the small movement of the movable block 9 causes the floor main 1 to be elastically deformed in the X axis direction by a small amount, and the locating is performed. The hole 1a fits tightly with the locating pin 2.

According to such a procedure, the floor main 1 can be positioned with the four locating pins, and according to the above-described method, the locating pins can be surely fitted into the locating holes whose positional accuracy varies in the X-axis direction. In addition, the locate pin can be supported with high rigidity, and the floor main 1 can be accurately positioned.

FIG. 3 shows another embodiment of the present invention. In this embodiment, a work base 4 having a pin diameter changing mechanism 13 incorporated therein is fixed to a hand mount 5a of a robot 5.

Here, the pin diameter changing mechanism 13 has four levers 15 (only two are shown in the figure) which are arranged radially with respect to the center pin C of the locate pin and each pivotally support the work base 4 via the pin 14. Four claws 16 each having a fan-shaped cross section and projecting upward from the upper surface of the work base 4 are connected to their levers 15.
3a and 3b so that the tips of the claws are closed as shown in FIGS. 3 (a) and 3 (b) and opened as shown in FIGS. 3 (c) and 3 (d). , And a central projection 17a and four arms 1 arranged in the work base 4.
Lever drive member 17 having 7b (only two are shown in the figure)
When the lever driving member 17 is raised based on the operation of the air cylinder 18, the central projection 17 a is moved to each lever as shown in FIG. 3 (b). The lower end of the lever 15 is urged radially outward from the center axis C to move each lever 15 as shown in FIG.
As shown in FIG. 3 (c), when the tips of the claws 16 are swung so as to close each other, and the lever driving member 17 is lowered based on the reverse operation of the air cylinder 18, the arm portion 17 as shown in FIG.
b urges the lower ends of the levers 15 toward the central axis C, and the levers 15 are opened as shown in FIG. A cylindrical surface around the axis C is roughly formed and rocked so as to function as a locate pin.

In the floor main positioning device including the pin diameter changing mechanism 13, the four claws 16 are closed to form a generally frustoconical surface on the side surfaces of the claws, thereby reducing the outer diameter of the locate pin. It has the same effect as the diameter,
When the work base 4 is lifted, these claws 16 can be securely inserted into the misaligned locate holes 19, and then the four claws 16 are opened to locate on the side of the claws. A substantially cylindrical surface having an outer diameter substantially equal to the inner diameter of the hole is formed, and the same operation as when the outer diameter of the locating pin is expanded is performed. In this state, the lever driving member 17 is operated by the air cylinder 18.
, The pawl 16 can be fixed in an open state, and the four pawls 16 can be closely fitted in the locate hole 1a to accurately position the floor main 1.

When the claw 16 is opened, the locate hole 1a is slightly moved, so that the floor main 1 is slightly elastically deformed in the direction opposite to the direction in which the locate hole is displaced.

As described above, the present invention has been described based on the illustrated examples. However, the present invention is not limited to the above-described examples, and the number of the locate holes and the locate pins to be inserted therein can be appropriately changed as necessary. However, the present invention can be applied to anything other than the floor main.

(Effect of the Invention) Thus, according to the work positioning method of the present invention, even if the position accuracy of the plurality of locate holes of the work varies with respect to the elastically deformable work, the locate pins can be securely fitted respectively. After that, the work can be accurately positioned.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a floor main positioning device in a vehicle body assembly stage of a vehicle body assembly line to which an embodiment of a work positioning method using a locating pin according to the present invention is applied. FIG. 3 (a) and 3 (b) are a plan view and a vertical sectional view showing a pin diameter changing mechanism of the floor main positioning device, and FIGS. 3 (c) and 3 (d). 4 (a) and 4 (b) are plan and longitudinal sectional views showing the pin diameter changing mechanism in an operation state different from those shown in FIGS. 4 (a) and 4 (b). FIGS. 4 (a) to 4 (e) show a conventional work positioning method using a locate pin. FIG. DESCRIPTION OF SYMBOLS 1 ... Floor main, 1a ... Locating hole 2 ... Locating pin 3, 3 Shuttle bar 4 ... Work base, 5 ... Positioning robot 6 ... Floating mechanism 7 ... Fixed block, 8 ... Casing 9 ... Movable block, 10 ... Spring 11 ... Plug, 12 ... Air cylinder 13 ... Pin diameter changing mechanism, 15 ... Lever 16 ... Claw, 17 ... Lever drive member 18 ... Air cylinder

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-265792 (JP, A) JP-A-62-292337 (JP, A) JP-A-62-74542 (JP, A) 65634 (JP, U) Fully open 61-141039 (JP, U) Fully open 61-20243 (JP, U) Fully open 63-116244 (JP, U) Fully open 61-190380 (JP, U) 63-7431 (JP, U) 51-42146 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23Q 3/18

Claims (2)

(57) [Claims] When a plurality of locating pins are fitted into a plurality of locating holes of a single elastically deformable work having a variation in position accuracy to position the work, the locating pin is supported by floating. After being displaced with respect to the supporting member to be fitted into the respective locating pin holes, the locating pins are forcibly returned to their proper positions on the supporting member while the work is elastically deformed between the locating pins. A work positioning method using a locating pin. 2. A method for positioning a plurality of locating pins in a plurality of locating holes of a single elastically deformable work, the plurality of locating holes having variations in positional accuracy, wherein the locating holes are sufficiently smaller than the inner diameter of the locating hole. After fitting the locate pins reduced in outer diameter into the locate holes, the work is elastically deformed between the locate pins, and the outer diameters of the locate pins are expanded to be substantially equal to the inner diameter of the locate holes. A work positioning method using a locate pin, wherein the work is fixed in an expanded state.