JP4611189B2 - Work positioning device - Google Patents

Description

  The present invention relates to a workpiece positioning apparatus, and more particularly to a workpiece positioning apparatus for accurately positioning a workpiece such as a cylinder head for an internal combustion engine when cutting the workpiece.

  In the machining line for cylinder heads made of aluminum alloy, the so-called multi-variety mixed-flow line type or multi-variety low-volume production type in which many types (multi-model or multi-type) of cylinder heads flow to a common line is the mainstream. The more versatile the machining equipment is so that it can handle various types of cylinder heads, the easier the positioning accuracy of the workpiece becomes (for example, see Patent Document 1). In this process, there are still many cases where processing is performed using a dedicated processing apparatus for each type.

For example, the finishing cutting process at the initial stage for the purpose of removing the sprue part and cast burr attached to the cylinder head rough material after casting is an example thereof, using a dedicated processing device prepared for each type, Processing is performed by positioning the outer shape portion of the cylinder head as a positioning reference.
JP 7-185981 A

  However, as long as it is a dedicated facility, when the workpiece shape is changed, it is necessary to modify the facility or purchase a new facility, which is not preferable because a large facility investment and a long preparation period are required.

  As a measure to solve these problems, the cylinder head coarse material is positioned with a predetermined jig, while a general-purpose industrial robot is equipped with a cutter unit for finishing cutting, and the above-mentioned gate is provided by this robot work. Although equipment has also been proposed to perform finish cutting for the purpose of removing parts and cast-off, when the workpiece shape is changed as in the above, it is necessary to perform setup change work such as correction of robot trajectory data. In addition, if the workpiece shape is significantly changed, the jig or the cutter unit needs to be remodeled, which requires a great investment in equipment and a long preparation period.

  On the other hand, a tilt-type work table (work table that can be turned upside down) to which a cylinder head to be machined is fixed, and at least one spindle that performs a predetermined cutting process on the cylinder head on the work table, If it is assumed that a machining center type cutting machine equipped with a cylinder head is used, the cylinder head conveyed by a predetermined conveying means is once received and positioned by a lifter table of a transfer carriage having a lifter function. The transfer carriage is moved to a position where the cylinder head facing the work table is moved, and the lifter table is lifted up at that position so that the cylinder head is seated on the work table and clamped by a clamper on the work table side. If you do, lift the lifter table In long as straightness of the trace it is guaranteed, and the from the work table abolished the locating pins, were found to be possible to simplify the structure of the work table while maintaining the versatility of the equipment.

  Therefore, the present invention is a general-purpose that can perform high-precision positioning for a plurality of types of workpieces typified by a cylinder head, for example, when employing a machining center type cutting device as described above and performing multi-product small-volume production. An object of the present invention is to provide a work positioning device with high performance.

The invention according to claim 1 is provided with a base and a pair of locate pins provided on the base, and by engaging the locate pin with any two holes of a workpiece having a plurality of holes. a device for positioning the workpiece, the pair of locating pins are both when has a separately positionable in a mutual approaching separation direction by the operation of the position adjustment actuator, each locator pin are each of conical The part opposite to the opposing surface is cut off with a surface parallel to the axis to form a semi-conical shape with a pair of positioning ridges, and each locating pin is engaged with a hole on the workpiece side. After performing the primary positioning, the positioning ridges are moved by moving the locating pins in directions away from each other. It is characterized by being adapted to perform the final positioning of the workpiece as a quasi.

In this case, it is desirable to employ, for example, an NC motor capable of numerical control as the position adjusting actuator.

More preferably, as described in claim 2, each of the locating pins can accommodate at least a plurality of types of workpieces having different hole positions and diameters, and the locating pin has a diameter larger than the diameter of the counterpart hole. On the other hand, it is assumed that the position adjusting actuator adjusts the position of the locating pin according to the type of the work.

In the invention described in claim 1, the workpiece having a plurality of holes to be positioned has a plurality of holes necessary for the original function of the workpiece on the same plane as described in claim 3. For example, a cylinder head for an internal combustion engine having a spark plug mounting hole or an injection nozzle body mounting hole is assumed. The spark plug mounting hole is a hole to which a spark plug is mounted in a cylinder head of a one-cylinder four-valve gasoline engine specification. Similarly, the injection nozzle body mounting hole is a direct injection diesel engine. This is the hole in the cylinder head where the body of the injection nozzle is installed. In this way, the cylinder head side positioning reference part is used as a spark plug mounting hole or injection nozzle body mounting hole, although the hole size and position are slightly different, the difference in engine type (cylinder head type or specifications) This is because the position is relatively constant regardless of the difference in the outer shape of the cylinder head.

  The workpiece positioning apparatus according to the invention described in claim 1 is assumed to be applied to, for example, the machining center type cutting apparatus described above. More specifically, a tilt-type work table to which a workpiece such as a cylinder head to be processed is fixed, and at least one main spindle that performs predetermined cutting on the work on the work table are provided. When it is premised on the use of a machining center type cutting apparatus, the workpiece conveyed by a predetermined conveying means is once received and positioned by a lifter table of a transfer carriage having a lifter function, and then the positioned workpiece is The transfer carriage is moved to a position facing the work table, and the lifter table is lifted up at that position to clamp the work on the work table while being clamped by the work table side clamper. A work positioning device according to claim 1 is used as a table. To.

When it is assumed that such a machining center type cutting apparatus is used, it is desirable that each locating pin is arranged in an upward posture on the base as described in claim 4 .

  Therefore, according to the first aspect of the present invention, when it is premised on the use of the machining center type cutting device described above, a cylinder head as a workpiece, for example, is attached to a cylinder block on a horizontal lifter table on the transfer carriage side. Is placed with the joint surface facing up, the locating pin having a substantially semi-conical shape engages with the spark plug mounting hole or the injection nozzle body mounting hole on the cylinder head side, and the cylinder head is conveyed at that stage. Therefore, relative positioning of the lifter table on the transfer carriage side and the cylinder head as the work is performed, and even if the transfer carriage moves, the relationship between the two remains unchanged.

  At this time, the primary positioning of the workpiece with respect to the lifter table is performed at the stage where each locating pin is engaged with the hole on the workpiece side, and then the locating pins are moved away from each other to make the positioning ridge line portion a reference. The final positioning of the workpiece is performed. That is, the positioning ridge line on the locate pin side and the spark plug mounting hole or the cylindrical surface on the injection nozzle body mounting hole side are in point contact, and relative positioning is performed by this point contact, enabling more accurate positioning. It becomes.

  Then, when the transfer carriage is moved to just below the work table on the cutting device side, and the lifter table is lifted up by the lifter function of the transfer carriage itself, the relative positioning state of the lifter table and the cylinder head as the workpiece is changed. Since the joint surface of the cylinder block with the cylinder block comes into close contact with the work table while maintaining the cylinder head, the clamp head attached to the work table side is clamped in this state. Is firmly clamped to the worktable. Since the locate pin loses its function when the cylinder head is clamped, only the lifter table of the transfer carriage is lowered.

  Since the relative positioning between the lifter table and the cylinder head is made in advance by the locate pin in the transfer process of the cylinder head, which is such a workpiece, the work table is only required if the lift-up path accuracy of the lifter table is guaranteed. The relative positioning accuracy between the cylinder head and the cylinder head is uniquely determined.

In addition, as described above, regardless of the difference in the engine type and the difference in the outer shape of the cylinder head, even if the position of the spark plug mounting hole or the injection nozzle body mounting hole serving as the positioning reference portion is substantially constant, It does not necessarily match completely. Therefore, in order to cope with a subtle difference in the position of the spark plug mounting hole or the injection nozzle body mounting hole for each engine type, the position of each locate pin is so-called, for example, by the operation of the position adjusting actuator as described in claim 2. Switch by NC control method. By doing so, positioning of various types of cylinder heads can be handled, and the versatility becomes extremely high.

  According to the first aspect of the present invention, after the primary positioning is performed by engaging the pair of locating pins having the pair of positioning ridge lines with the holes on the workpiece side, the locating pins are moved away from each other. As a result, the final positioning of the workpiece is performed based on each positioning ridge line as described above, enabling high-precision positioning regardless of the type or type of workpiece and greatly improving its positioning accuracy. In addition, the position of the locating pin itself can be adjusted, so it can be used for positioning of many types and types of workpieces, and it is not necessary to modify or newly install a positioning device when changing the shape of the workpiece, reducing capital investment. This has the effect of realizing a workpiece positioning device that is truly versatile.

  1 and the following drawings are views showing a more specific preferred embodiment of a cutting apparatus using a workpiece positioning device according to the present invention, in particular FIG. 1 is a plan view thereof, and FIG. 2 is a plan view of FIG. 3 is an enlarged explanatory view of the left side surface, and FIG. 3 is a cross-sectional view taken along line AA of FIG. The cutting device of the present embodiment, as described above, aims to cut and remove the sprue portion and cast flash that are unavoidably attached to the outer peripheral surface of the aluminum alloy cylinder head rough material after die casting. It shows an example applied to the finish cutting line.

  As shown in FIG. 1, the finish cutting process line is roughly divided and arranged side by side with a carry-in conveyor 1 having a front-packed storage function for carrying a cylinder head rough material (hereinafter referred to as a workpiece) W after casting. Two machining centers 2 and 3, a self-propelled multi-joint type handling robot 4 for supplying workpieces W carried by the carry-in conveyor 1 sequentially to the two machining centers 2 and 3, and two machining centers 2 , 3 and an unloading conveyor (belt conveyor) 5 for unloading workpieces. Each of the machining centers 2 and 3 has an independent booth structure surrounded by a booth plate 6 as shown in FIGS. Then, between each of the machining centers 2 and 3 and the robot path 7, a reciprocating movement is performed between the machining centers 2 and 3 and the workpiece W supplied from the handling robot 4 is received and supplied to the machining centers 2 and 3. A carriage 8 is provided for each.

  Each machining center 2, 3 includes a spindle head 10 having a spindle 9 on which a predetermined cutting tool T is mounted at the tip, a work base unit 11, an automatic tool changer (hereinafter referred to as a tool changer) 12, and the like. Since a plurality of cutting tools T are prepared in advance in the tool magazine 13 of the tool changer 12 as is well known, the spindle head 10 uses the degree of freedom of movement of three orthogonal axes to obtain a tool magazine. 13 has a function of exchanging tools autonomously. Since the machining centers 2 and 3 have the same structure, common parts are denoted by the same reference numerals.

  The work base unit 11 is provided with an index type work table 15 that can be rotated by 360 degrees when the NC motor 14 is started. After the work W is clamped by a plurality of clampers 16 as will be described later, The posture of the workpiece W can be arbitrarily changed. As shown in FIGS. 1 and 2, the work table 15 is formed in a substantially rectangular frame shape in which most of the center other than the part where the work W is seated has a hollow shape. W is firmly clamped.

  On the other hand, the transfer carriage 8 reciprocates along the rail 18 on the gantry 17 by the activation of the NC motor 23 and includes a lifter table 20 as a base that moves up and down by the expansion and contraction operation of the lift cylinder 19. ing. Then, as shown in FIG. 2, the transfer carriage 8 that has received the workpiece W on the lifter table 20 that is in the lowered state at the workpiece receiving position P1 travels to the workpiece delivery position P2, and the lifter table 20 is moved to that position. By lifting up, the work W is delivered to the work table 15 side.

  A pair of left and right locating pins 21 are provided on the upper surface of the lifter table 20 as shown in FIG. 4A. By engaging these locating pins 21 with existing mounting holes 22 on the workpiece W side, the lifter table 20 is lifted. The relative positioning of the table 20 and the workpiece W is performed. Each locating pin 21 is individually provided with an NC motor 25. By the operation of the NC motor 25, the locating pin 21 slides in the direction of arrow a, and its position can be arbitrarily adjusted.

  Further, each locating pin 21 is formed in a substantially semi-conical truncated cone shape by cutting out a part of the truncated cone shape as shown in FIG. 5 in addition to FIG. 4, and the cut portion is formed of the locating pin 21 itself. A pair of positioning ridge lines 24 are formed on each locate pin 21 by cutting with a plane parallel to the axis. Then, the workpiece W is positioned on the basis of the positioning ridge line portion 24 of the locate pin 21.

  Further, the mounting hole 22 on the workpiece W side is selected at a position where the position is almost constant regardless of the type of workpiece W (difference in engine or cylinder head type or specification). As shown in FIGS. 6 and 7, in the case of a gasoline engine specification of an in-line 4-cylinder type and a 4-valve type per cylinder, the spark plug attachment holes 22, 22. Used as an engagement site with the locate pin 21. Similarly, in the case of a direct-injection diesel engine, an injection nozzle body mounting hole that is set at substantially the same position as the spark plug mounting hole 22 is used as an engagement site with the locate pin 21.

  Here, as shown in FIG. 4B, the diameter of each locating pin 21 is formed sufficiently smaller than the diameter of the mounting hole 22 such as the other spark plug mounting hole or the injection nozzle body mounting hole. The position of each locate pin 21 can be finely adjusted by operating the NC motor 25 as described above.

  Therefore, according to the cutting apparatus configured as described above, as shown in FIG. 1 and FIG. If stored, the type of the work W in the front row on the carry-in conveyor 1 is detected by a sensor (not shown). For example, the type of the workpiece W is detected by photoelectrically detecting the appearance feature of the workpiece W. Each workpiece W stands by with its joint surface with the cylinder head facing upward. Then, the workpiece W after this type detection is gripped by the robot hand 26 and then transferred onto the lifter table 20 of the transfer carriage 8 waiting at the workpiece receiving position P1 on the one machining center 2 side, for example. .

  Prior to this, the NC motor 25 on the lifter table 20 is operated in response to the above type information, and the locate pin 21 is moved to a position set in advance for each type of the workpiece W to be positioned. As a result, when the workpiece W transported by the robot hand 26 is placed on the lifter table 20 of the transfer carriage 8, each locating pin 21 is moved to the workpiece as shown in FIGS. The W-side mounting hole 22 is smoothly engaged, and rough so-called primary positioning between them is performed. At this time, if each locating pin 21 and the mounting hole 22 are simply engaged, a gap may be formed between them, and there is a limit to improvement in positioning accuracy.

  Therefore, when the workpiece W is transferred onto the lifter table 20 and each locating pin 21 and the mounting hole 22 are engaged, and the robot hand 26 opens the workpiece W, each NC motor 25 is further operated to move the workpiece W by a predetermined amount. The locate pin 21 is moved in the direction of arrow C in FIG. 4B and FIG. As a result, a pair of positioning ridge line portions 24 for each locating pin 21 is brought into pressure contact with the inner cylindrical surface of the mounting hole 22 on the mating side to exert a secondary positioning function. The final positioning of the workpiece W is performed with point contact with the inner peripheral surface. This completed positioning state is shown in FIG.

  When the handling robot 4 finishes supplying the workpiece W to the transfer carriage 8 on the one machining center 2 side, the handling robot 4 grips the next workpiece W on the carry-in conveyor 1 and then moves on the robot track 7. Is moved to the other machining center 3 side, and the workpiece W is supplied to the transfer carriage 8 on the other machining center 3 side. Therefore, the other machining center 3 side operates in exactly the same manner as the other machining center 2 side. Will be repeated.

  As described above, the position of the substantially semi-conical truncated pin 21 is adjusted according to the type of the workpiece W, and after each locate pin 21 and the mounting hole 22 on the workpiece W are engaged, the positioning pin 21 is further attached to the mounting hole. The locating pin 21 is moved in the radial direction and the locating ridge line portion 24 on the locating pin 21 side is brought into pressure contact with the inner peripheral surface of the mounting hole 22 to bring them into point contact with each other. Although it is assumed to be used, any type of workpiece W can be reliably and accurately positioned.

  When the final positioning of the workpiece W on the lifter table 20 is completed, the transfer carriage 8 travels from the workpiece receiving position P1 to the workpiece delivery position P2 and stops as shown in FIGS. . The workpiece delivery position P2 is set in advance so as to be a position immediately below the work table 15 in the work base unit 11, and at the same time, the work table 15 stands by in a horizontal state with the workpiece seating surface facing downward.

  When the transfer carriage 8 is positioned at the workpiece transfer position P2 as described above, the lift cylinder 19 attached to the transfer carriage 8 is extended as shown in FIG. 10 in addition to FIG. The work W positioned above is pushed up together with the lifter table 20. When the workpiece W is pushed up, the upper surface of the workpiece W, that is, the portion to be a joint surface with the cylinder head is seated on the workpiece table 15, so that a plurality of clampers 16 attached to the workpiece table 15 side in that state are left. To clamp the work W so as to be pressed against the seating surface on the work table 15 side. When the workpiece W is clamped on the workpiece table 15 side, the lift cylinder 19 is contracted and the lifter table 20 is lowered, and the entire transfer carriage 8 is moved to the original workpiece receiving position P1 and temporarily stands by. Thereafter, the same operation as described above is repeated.

  In this way, the workpiece W previously positioned on the lifter table 20 with the movable locate pin 21 is clamped to the workpiece table 15 side in the positioning state, and then the positioning by the locate pin 21 is released. Thus, regardless of the type of the workpiece W, the workpiece W can be transferred to the workpiece table 15 side and clamped while the positioning accuracy by the locate pin 21 is maintained. Even when the work table 15 is not provided with positioning means such as a locating pin other than the clamper 16 in order to cope with various types of workpieces W, the positioning accuracy of the locating pin 21 on the lifter table 20 side is all determined. Although depending on the accuracy, high-accuracy positioning can be performed regardless of the type of the workpiece W as described above.

  When the workpiece W is positioned and clamped to the workpiece table 15, the workpiece table 15 is appropriately indexed and rotated as shown in FIGS. 11A and 11B in addition to FIGS. 11 (A and B in FIGS. 11A and 11B show a state in which the workpiece W is inverted by 180 degrees with respect to each other), the spindle 9 is connected to the tool changer 12 according to the machining position or the type of the workpiece W. The cutting tool T performs finish cutting processing such as cutting of the sprue portion attached to the workpiece W and removal of the cast-off while performing automatic replacement of the tool T. In this case, since the work W can be rotated 360 degrees together with the work table 15, the work table 15 has a so-called hollow shape and a flat shape. The six surfaces of the workpiece W can be cut without re-working. Further, machining position information and the like corresponding to the type of workpiece W are stored and set in advance in the control devices of the machining centers 2 and 3 together with the type information of the tool T to be previously selected. Called sequentially accordingly.

  When the cutting of the work W is completed, the work table 15 returns to the original horizontal state as shown in FIG. 10, while the drop lifter 27 waiting just below the work table 15 is operated as shown in FIG. To do. That is, the lift operation of the lift cylinder 28 of the drop lifter 27 raises the table 29 to a position where the work W can be received, and in this state, the clamper 16 on the work table 15 side performs an unclamping operation. W is transferred to the table 29 of the drop lifter 27. Further, when the table 29 is lowered, the machined workpiece W stands by at its lowered position, and the transfer carriage 8 advances to the workpiece delivery position P2 when machining the next workpiece W as shown in FIG. As a result, it is pushed out to the carry-out conveyor 5 side by the lifter table 20 of the transfer carriage 8, and finally transferred to the carry-out conveyor 5 so as to slide down the inclined chute 51 and carried out to the subsequent process. The operation similar to the above is repeated.

  As described above, according to the present embodiment, the locating pin 21 is provided on the transfer carriage 8 having a lifter function for transferring the work W to the work base unit 11 on the machining center 2 or 3 side, and the locating pin 21 is actively used. In addition to being able to adjust the position and exhibiting the primary positioning function and the secondary positioning function, the locating pin 21 has versatility so that it can handle various types of workpieces W. The work table 15 on the work base unit 11 side only needs to have a clamping function capable of dealing with at least various types of works W, and the work base unit 11 and the machining centers 2 and 3 themselves are highly versatile. It will be possible to cope with the form without difficulty.

  In the above embodiment, an example is shown in which tool exchange is performed directly between the spindle 9 and the tool magazine 13 without using a tool exchange arm. If necessary, a tool changing arm may be used when changing the tool.

Plane explanatory drawing which shows the whole structure of the cutting device provided with the workpiece | work positioning device which concerns on this invention. FIG. 2 is an explanatory side view on the left side of FIG. 1. Cross-sectional explanatory drawing which follows the AA line of FIG. (A) is an enlarged explanatory view showing the interrelationship between the work and the transfer carriage, (B) is an enlarged view of the main part when FIG. FIG. 5 is an enlarged explanatory view of the locate pin shown in FIG. The perspective view which shows the structure of a cylinder head as an example of a workpiece to be processed. FIG. 7 is an explanatory plan view of the cylinder head shown in FIG. 6. Explanatory drawing which shows the mutual relationship between a transfer trolley | bogie and the work table of the work base unit side. Explanatory drawing which shows the mutual relationship between a transfer trolley | bogie and the work table of the work base unit side. Explanatory drawing which shows the mutual relationship between a transfer trolley | bogie and the work table of the work base unit side. (A), (B) is explanatory drawing which shows the relationship between the spindle head and work table in process.

Explanation of symbols

8 ... Transfer truck 19 ... Lift cylinder 20 ... Lifter table (base)
21 ... Locate pin 22 ... Mounting hole (ignition plug mounting hole or injection nozzle body mounting hole)
24 ... Positioning ridge line part 25 ... NC motor (actuator for position adjustment)
W ... Work (rough cylinder head)

Claims (4)

A device including a base and a pair of locate pins provided on the base, and positioning the work by engaging the locate pin with any two holes of the work having a plurality of holes. ,
The pair of locating pins are both when has a separately positionable in a mutual approaching separation direction by the operation of the position adjustment actuator,
Each of the locating pins is formed as a substantially semi-conical shape having a pair of positioning ridge lines by excising a portion of the conical shape opposite to the surface opposite to each other with a surface parallel to the axis.
After each positioning pin is engaged with the hole on the workpiece side for primary positioning, the positioning pins are moved away from each other so that the workpiece is finally positioned with reference to the positioning ridge line portion. A workpiece positioning device characterized by that. Each of the above locate pins is compatible with at least a plurality of types of workpieces having different hole positions and diameters,
While forming the diameter of the locate pin smaller than the diameter of the counterpart hole,
2. The work positioning apparatus according to claim 1, wherein the position adjusting actuator adjusts the position of the locate pin in accordance with the type of the work. The workpiece positioning apparatus according to claim 2, wherein the workpiece to be positioned has a plurality of holes on the same plane necessary for the original function of the workpiece. 4. The work positioning apparatus according to claim 3 , wherein each locating pin is arranged in an upward posture on the base .

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