JP2008062350A - Workpiece seating sensor, locator using the same, and method of sensing seating of workpiece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a workpiece seating sensor having a similar function to that of a photoelectric-sensor-type workpiece seating sensor but with its cost reduced. <P>SOLUTION: A dog 38 is vertically movably supported at an upper end of a guide tube 37 having a head 34a of a proximity sensor 34 exposed at a lower end, a sensing plate 40 is vertically movably provided in the guide tube 37, and compression coil springs 41 and 42 oppositely working to each other are provided on and under the plate 40. A stroke S2 of the sensing plate 40 is set to be smaller than a stroke S1 of the dog 38. The dog 38 comes into contact with a workpiece, thereby causing the sensing plate 40 to displace while following the movement of the dog 38, and the seating of the workpiece on the dog 38 is indirectly detected by the proximity sensor 34. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a workpiece seating detection device that detects seating of a workpiece at a predetermined position in various production lines, a locating device using the workpiece, and a workpiece seating detection method, and in particular, according to the movement of a dog that contacts the workpiece. The present invention relates to a workpiece seating detection device in which seating is indirectly detected by a proximity sensor, a locating device using the workpiece seating detection device, and a workpiece seating detection method.

  As shown in FIG. 7, as a workpiece seating detection device used in this kind of workpiece seating detection technique, for example, in a car body assembly process, as shown in FIG. In addition to the proximity sensor 103 being attached so that the seating of the workpiece W1 or W2 is directly detected by the proximity sensor 103, as described in Patent Document 1, the workpiece seating surface 102 itself can appear and disappear. There is one in which a pin is arranged and a displacement of the pin accompanying the seating of the workpiece W1 or W2 is detected by, for example, a proximity sensor facing the other end of the pin.

  However, in the former direct detection method using the proximity sensor 103, the degree of freedom with respect to the difference between the shapes of the workpieces W1 and W2 is small and lacks versatility, and spattering during welding adheres to the detection surface of the proximity sensor 103, resulting in false detection. There is a risk of inviting. Further, in the latter pin combination method, as described in Patent Document 1, since the detectable region by the pin is extremely small, it is not possible to sufficiently cope with the difference in the work shape as described above.

  For this reason, for example, instead of the proximity sensor 103 shown in FIG. 7, a workpiece seating detection device 105 as shown in FIG. 8 is provided and the workpiece W1 or W2 is seated on the workpiece seating surface 102 on the locate pin 104 side simultaneously. The dog 106 on the seating detection device 105 side is also displaced by bringing the workpiece W1 or W2 into contact therewith, and the seating of the workpiece W1 or W2 is indirectly performed by the photoelectric sensor 107 having the inner bottom surface of the dog 106 as a reflection surface. Some have been proposed to detect.

The workpiece seating detection device 105 extrapolates a bottomed cylindrical dog 106 so as to be movable up and down in a guide tube 108 having a so-called light projecting / receiving unit-integrated photoelectric sensor 107 at the lower end. A return spring 109 is interposed between the set collar 110 and the dog 106 screwed on the outer periphery, and the irradiation light from the photoelectric sensor 107 is reflected with the inner bottom surface of the dog 106 as a reflecting surface. Then, when the dog 106 is lowered by a predetermined amount by the seating of the work W1 or W2 on the dog 106, the reflected light from the inner bottom surface of the dog 106 can be captured by the photoelectric sensor 107 for the first time. The seating of the workpiece W1 or W2 on the side workpiece seating surface 102 can be indirectly detected by the photoelectric sensor 107.
JP 2002-225759 A

  However, in the type using the above-described photoelectric sensor 107, the problems of the technology described in FIG. 7 and Patent Document 1 described above are eliminated, but the ultra-small type photoelectric sensor 107 is, for example, the proximity sensor 103. Compared to the above, it is expensive. In particular, it is necessary to attach the photoelectric sensor 107 to a large number of locating devices 104 that are used simultaneously in the body assembly equipment of an automobile. Therefore, the use of the photoelectric sensor 107 greatly increases the cost. That is not preferable.

  The present invention has been made paying attention to such a problem, and in particular, a workpiece seating detection device capable of reducing the cost while having the same function as the photoelectric sensor type workpiece seating detection device. It is to provide.

  The invention described in claim 1 is a workpiece seating detection device that indirectly detects seating of a workpiece on the dog by a proximity sensor in accordance with the movement of the dog when the dog abuts on the workpiece. In addition, a dog capable of approaching and separating from the detection surface is disposed on the front side of the detection surface of the proximity sensor, and detection that functions as a proximity body while following the movement of the dog between the detection surface and the dog. A member is arranged, and the displacement amount of the detection member that can approach and separate from the detection surface is set smaller than the displacement amount of the dog.

  In this case, as described in claim 6, instead of indirectly detecting the seating of the work on the dog by the proximity sensor in accordance with the movement of the dog when the dog abuts on the work, the seating reference A workpiece seating detection device that indirectly detects the seating / positioning state of the workpiece with respect to the seating reference member according to the movement of the dog by the dog abutting on the workpiece positioned by sitting on the member; In addition, as described in claim 7, the seating reference member may be disposed in proximity to the workpiece seating detection device itself.

  The invention described in claim 8 is based on the premise of using the workpiece seating detection device described in claim 6 or 7, and is inserted into a locating hole formed in the workpiece to position and support the workpiece. A locating device having a clamping function, a locating pin having a workpiece seating surface on the base side and functioning as a positioning reference portion, and a built-in locating pin that advances and retracts in a direction approaching and separating from the workpiece seating surface. A clamp arm that clamps a workpiece positioned by the locating pin by being driven between the workpiece seating surface, a linear motion actuator having a piston coupled to the clamp arm to drive the clamp arm forward and backward, and Item 6 or 7 is provided with the workpiece seating detection device, and the locate pin of the workpiece seating detection device is provided. Characterized in that it is intended to function as a seat reference member.

  Further, the invention according to claim 9 captures the technique according to claim 1 as a workpiece seating detection method, and a workpiece against the dog according to the movement of the dog when the dog abuts against the workpiece. As a workpiece seating detection method that indirectly detects the seating of a proximity sensor, a dog that can approach and separate from the detection surface is arranged on the front side of the detection surface of the proximity sensor, and the detection surface A detection member that functions as a proximity body while being displaced following the movement of the dog is arranged between the dog and the displacement amount of the detection member that can approach and separate from the detection surface is smaller than the displacement amount of the dog. It is characterized by detecting the seating of the workpiece in a state restricted to the above.

  Therefore, in at least the first and ninth aspects of the present invention, when a work is seated on the dog, the proximity sensor detects the seating of the work by using a detection member that displaces following the movement of the dog as a proximity body. Since the displacement amount of the detection member that can approach and separate from the detection surface is set to be smaller than the displacement amount of the dog, for example, the displacement amount of the dog when the workpiece is seated differs depending on the difference of the workpiece shape, etc. However, the proximity sensor can reliably detect the seating of the workpiece with the displacement of the proximity member that is displaced following the movement of the dog, and can easily cope with the detection of the seating of a plurality of types of workpieces.

  According to the first and ninth aspects of the invention, since the detection member that follows and displaces the movement of the dog when contacting the workpiece is used as the proximity body, the proximity sensor detects the workpiece sitting indirectly. Despite the use of proximity sensors, it is possible to handle multiple types of workpiece seating detection without being affected by differences in workpiece shapes, and to significantly reduce costs compared to conventional photoelectric sensor types. Is possible.

  FIG. 1 is a diagram showing a schematic structure of a locating device based on the combined use of a workpiece seating detection device according to the present invention, and shows an example of one used as a part of an automobile body assembly facility.

  As shown in FIGS. 1A and 1B, the locating device 1 is erected on a locator column 31 via a bracket 32, and a workpiece is placed on the side of the locating device 1 via an auxiliary bracket 33. A seating detection device (hereinafter simply referred to as “seat detection device”) 30 is attached.

  2 to 4 show details of the locating device 1, and the locating device 1 is roughly divided into seats that are inserted into the locating holes R of the panel-like workpiece W1 or W2 and serve as positioning reference portions for the workpiece W1 or W2. A locating pin 2 at the tip that functions as a reference member, a flat block-shaped post 3 to which the locating pin 2 is mounted, and a double-acting type actuator as a linear motion actuator that forms a flat block like the post 3 It comprises a clamp cylinder (air cylinder) 4. Note that this type of clamp cylinder (air cylinder) is sometimes referred to as a plate cylinder because of its shape.

  The locating pin 2 is integrally formed with a seating block 2b having a substantially rectangular tube shape in plan view on the base side of the pin portion 2a having a tapered tip, and the upper surface of the seating block 2b is concentric with the pin portion 2a. It functions as an annular workpiece seating surface 2c. On the other hand, the post 3 is formed by integrally extending a rectangular tube-shaped shaft portion 3b from a wide pedestal portion 3a. The post 3 has a circular guide hole 3c in the longitudinal direction along with the seating block 2b on the locating pin 2 side. Is formed. Then, after the seating block 2b on the locating pin 2 side is ruggedly fitted to the tip of the shaft portion 3b on the post 3 side, the locating pin has four bolts 5 screwed from the work seating surface 2c side of the seating block 2b. 2 is connected and fixed concentrically to the tip of the post 3.

  Further, the post 3 has its pedestal portion 3a seated on the rod side cover 9 of the clamp cylinder 4 and is concentric with the tip of the clamp cylinder 4 with two bolts 6 screwed from the pedestal portion 3a side. It is connected and fixed in a shape.

  Here, the clamp cylinder 4 seals both ends of a cylinder tube 7 in which a cylinder chamber having an oval cross-sectional shape is formed with a head-side cover 8 and a rod-side cover 9, and a bolt 10 causes a piston rod 11 to be The connected oval-shaped piston 12 is accommodated in the cylinder chamber and will be described in detail later.

  The pin portion 2a of the locating pin 2 is formed with a slit groove 13 penetrating in the diametrical direction. The slot groove 13 communicates with the internal space on the side of the seating block 2b. In addition, a pair of clamp arms 14 are inserted and arranged in a substantially bowl shape so as to straddle the inside of the seating block 2b and the shaft portion 3b on the post 3 side. These two pairs of clamp arms 14 are formed by superposing the substantially hook-shaped tip portions 14a with the directions of the substantially hook-shaped tip portions 14a being opposite to each other. The other end is connected to the piston rod 11 of the clamp cylinder 4 with a connecting pin 15 while facing the outside from the split groove 13. Further, a substantially U-shaped groove cam 16 formed on each clamp arm 14 is engaged with a fixing pin 17 horizontally mounted in the radial direction of the shaft portion 3 b on the post side 3.

  Therefore, if the clamp cylinder 4 is expanded and contracted, each clamp arm 14 performs a clamping and unclamping operation between the clamping position P1 indicated by a solid line and the unclamping position P2 indicated by a virtual line in FIG. In the clamped state, the workpiece W1 or W2 is clamped in a clamped state by the tip end portion 14a of each clamp arm 14 and the workpiece seating surface 2c on the seating block 2b side. In addition, when the clamp arm 14 is in an unclamped state as indicated by an imaginary line P2 in FIG. 1, it is set so that the hook-shaped tip portion 14a of each clamp arm 14 is entirely within the diameter of the pin portion 2a of the locate pin 2. Accordingly, the mutual engagement between the locate pin 2 and the locate hole R or the disengagement of the locate hole R from the locate pin 2 is performed without difficulty.

  That is, when the workpiece W1 or W2 is positioned and clamped using the locate pin 2 as a reference, the clamp arm 14 built in the locate pin 2 is in an unclamped state as indicated by a virtual line P2 in FIG. The clamp cylinder 4 is in an extended state unlike the state shown by the solid line in FIG. 1), and the peripheral portion of the locate hole R of the workpiece W1 or W2 is inserted while the pin portion 2a of the locate pin 2 is inserted into the locate hole R of the workpiece W1 or W2. The part is seated on the workpiece seating surface 2c.

  When the workpiece W1 or W2 is seated and positioned with reference to the locate pin 2, the clamp cylinder 4 is contracted. As the clamp cylinder 4 contracts, each clamp arm 14 shifts from the unclamped state indicated by the phantom line P2 in FIG. 1 to the clamped state indicated by the solid line P1 in FIG. The shaped tip portion 14a gradually protrudes from the slit groove 13 to the outside of the pin portion 2a in the locate pin 2. Finally, the peripheral portion of the locate hole R in the counterpart panel W is clamped between the tip 14a of each clamp arm 14 and the workpiece seating surface 2c on the seating block 2b side, and the workpiece W1 or W2 is It is clamped firmly in the above-mentioned positioning state.

  Here, as shown in FIG. 1 and FIG. 2, a magnet (permanent magnet) 18 is embedded in the piston 12 of the crank cylinder 4 in advance, and at the position corresponding to the magnet 18 on the outside of the cylinder tube 7. As a magnetic force sensitive detection means, for example, two contact type or wireless point type switches 19 and 20 such as a reed switch are mounted side by side. These switches 19 and 20 are arranged so that the detection reference portions 19a and 20a are offset by a predetermined amount α in the moving direction of the piston 12.

  Then, when the magnet 18 is displaced together with the piston 12, the operation limit position of the piston 12, that is, whether the clamp cylinder 4 is in the contracted state or in the extended state, in other words, whether the clamp arm 14 is in the clamped state or not. Whether each is in a clamped state is individually detected by the respective switches 19 and 20. Note that reference numerals 21 and 22 in FIG. 2 indicate lead wires with connectors 21a and 22a attached for taking out signals from the switches 19 and 20, respectively.

  FIG. 5 shows details of the seating detection device 30. As shown in the figure, the seating detection device 30 is configured with a proximity sensor 34 as a main element, and an auxiliary bracket 33 is sandwiched between a base portion 37a of a guide tube 37 to be described later and a lock nut 35. The auxiliary bracket 33 is fixed.

  The proximity sensor 34 has a cylindrical head portion 34a with a tip end surface serving as a detection surface 34b, and a hollow thread so that the head portion 34a extends in the axial direction on the external thread of the head portion 34a. A guide tube 37 is screwed. The upper end of the guide tube 37 is covered with a bottomed cylindrical dog 38 in the form of a cap by an extrapolation method, and the dog 38 slides on the guide tube 37 via a bush 39. In other words, the dog 38 can move up and down with respect to the guide tube 37, so that the dog 38 can approach and separate from the detection surface 34 b of the proximity sensor 34.

  In addition, a detection plate 40 as a stepped disk-shaped detection member is inserted in the guide tube 37 so as to be movable up and down, and a compression coil as a projectile member that antagonizes each other above and below the detection plate 40. The springs 41 and 42 are interposed individually. More specifically, a relatively short compression coil spring 42 is interposed between the base portion 37 a of the guide tube 37 and the detection plate 40, and between the detection plate 40 and the inner bottom surface of the dog 38. Another compression coil spring 41 that is relatively long is interposed, and acts on the detection plate 40 so that the spring forces of both the compression coil springs 41 and 42 antagonize each other. Therefore, in the so-called no-load state where the workpiece W1 or W2 is not in contact with the dog 38, the state shown in FIG. 5 is self-maintained. On the other hand, when a downward external force is applied to the dog 38, the dog 38 moves as described later. The detection plate 40 is adapted to follow and be displaced. The spring constant of the lower compression coil spring 42 is set smaller than the spring constant of the upper compression coil spring 41.

  Here, the stroke S1, which is the displacement amount of the dog 38 with respect to the guide tube 37, is regulated by the inner bottom surface of the dog 38 coming into contact with the upper end surface of the guide tube 37, as shown in FIG. The stroke S2, which is the displacement amount of the detection plate 40 that is displaced following the movement of the dog 38, is regulated by contacting the detection surface 34b of the proximity sensor 34 as shown in FIG. The maximum stroke S2 is set to be significantly smaller than the maximum stroke S1 of the dog 38.

  Therefore, according to the locating device 1 that uses such a seating detection device 30 as shown in FIG. 1, for example, a positioning clamp for a flat workpiece W1 of the A model and a positioning clamp for a workpiece W2 of the B model having the inclined portion Q are provided. Assuming that the locating device 1 is used in common, both of the two types of workpieces W1 and W2 immediately before the workpieces W1 and W2 are seated on the workpiece seating surface 2c of the locating pin 2 on the locating device 1 side. The height position of the workpiece W1 or W2 comes into contact with the dog 38 of the seating detection device 1 and descends by a predetermined amount, and the relative positional relationship with the locating device 1 is set in advance.

  On the locating device 1 side, the clamp arm 14 shown in FIG. 2 is in an unclamped state prior to the start of the sitting operation of the workpiece W1 or W2 on the locating pin 2.

  Then, as described above, for example, when the workpiece W1 starts the seating positioning operation with respect to the locating device 1, the dog 38 of the seating detection device 1 which is initially in an unloaded state as shown in FIG. When the work W1 comes into contact, the dog 38 is lowered as shown in FIG. 5B, and the detection plate 40 is also brought close to the detection surface 34b of the proximity sensor 34 so as to follow the movement of the dog 38. And descend. In this case, when the detection plate 40 approaches the detection surface 34b to a distance that can be detected by the proximity sensor 34, that is, when the distance formed between the detection surface 34b and the detection plate 40 becomes the operating distance, the proximity sensor 34 starts detecting the detection plate from this point. The seating of the workpiece W1 is detected by turning ON the 40 as a proximity body.

  Thereafter, the workpiece W1 is still lowered until it sits on the workpiece seating surface 2c of the locating pin 2 on the locating device 1 side and stops still, so that the dog 38 and the detection plate 40 that follows the dog 38 are shown in FIG. Still further, it is lowered by a predetermined amount, and in the state shown in FIG. 5C, the lowering operation of the dog 38 and the detection plate 40 is completed together with the seating operation of the workpiece W1 on the workpiece seating surface 2c, and then comes to rest. In this state, since the detection plate 40 abuts on the detection surface 34b of the proximity sensor 34 and is restrained at that position, the proximity sensor 34 keeps the ON state from the past using the detection plate 40 as a proximity body. At the same time, although the dog 38 can be lowered to the so-called bottom-out state with respect to the guide tube 37 as shown in FIG.

  Then, on the condition that the proximity sensor 34 detects the seating of the workpiece W1 on the workpiece seating surface 2c as described above, the clamp arm 14 is clamped based on the contraction operation of the clamp cylinder 4 of the locating device 1 shown in FIG. In operation, the workpiece W1 is firmly clamped against the workpiece seating surface 2c.

  Here, as described above, at the stage where the seating positioning of the work W1 of the A vehicle type with respect to the locating device 1 is completed, as shown in FIG. 6C, the dog 38 leaves the surplus stroke S3. It is possible to descend by the stroke S3.

  Then, as shown in FIG. 1, assuming that the B-type work W2 having the inclined portion Q is positioned and clamped by the common locating device 1 instead of the previous A-type work W1, the work W2 of the B-type. Has an inclined portion Q, and therefore, when the seating detection device 30 detects the seating of the workpiece W2, the dog 38 is pushed down more than the case of the workpiece W1 of the A vehicle type. In other words, the stroke of the dog 38 required for detecting the seating of the work W2 of the B vehicle type becomes larger than that of the work W1 of the A vehicle type.

  On the other hand, as shown in FIG. 6C, as described above, the dog 38 still has the surplus stroke S3 when the seating detection of the workpiece W1 of the A vehicle type is completed. Therefore, compared with the stroke of the dog 38 necessary for detecting the seating of the workpiece W1 of the A model, the increment of the stroke of the dog 38 required for detecting the seating of the workpiece W2 of the B model is even within the range of the surplus stroke S3. For example, the same behavior as in the case of FIG. 6 can be easily coped with not only the work W2 of the B vehicle type but also the seating detection of the work of other vehicle types.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows specific embodiment of this invention, (A) is schematic explanatory drawing of the locating apparatus used together with the workpiece seating detection apparatus, (B) is a right view of the same figure (A). Explanatory sectional explanatory drawing of the locating apparatus shown in FIG. The left view of FIG. The top view of FIG. The expanded sectional view which shows the detail of the workpiece | work seating detection apparatus shown in FIG. Process explanatory drawing which shows the action | operation of the workpiece | work seating detection apparatus shown in FIG. Explanatory drawing which shows an example of the conventional workpiece seating detection apparatus. Cross-sectional explanatory drawing which shows another example of the conventional workpiece seating detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Locating device 2 ... Locating pin (seating reference member)
2c ... Workpiece seating surface 4 ... Clamp cylinder (Direct acting actuator)
DESCRIPTION OF SYMBOLS 14 ... Clamp arm 30 ... Work seating detection apparatus 34 ... Proximity sensor 34a ... Head part 34b ... Detection surface 37 ... Guide tube 38 ... Dog 40 ... Detection plate (detection member)
41. Compression coil spring (elastic body)
42 ... Compression coil spring (elastic body)
R ... Locate hole W1 ... Panel-like workpiece W2 ... Panel-like workpiece

Claims (9)

A workpiece seating detection device that detects the seating of a workpiece on the dog indirectly with a proximity sensor in accordance with the movement of the dog by contacting the workpiece,
A detection member that functions as a proximity member while disposing a dog that can be moved toward and away from the detection surface on the front side of the detection surface of the proximity sensor and following the movement of the dog between the detection surface and the dog. And place
A workpiece seating detection device, wherein a displacement amount of a detection member capable of approaching and separating from the detection surface is set smaller than a displacement amount of a dog.   2. The workpiece seating detection device according to claim 1, wherein elastic bodies that antagonize each other are interposed between the proximity sensor and the detection member and between the detection member and the dog.   3. The workpiece seating detection device according to claim 2, wherein a spring constant of an elastic body interposed between the proximity sensor and the detection member is set smaller than a spring constant of the other elastic body. .   The workpiece seating detection device according to any one of claims 1 to 3, wherein a displacement amount of the detection member is regulated by contact between the detection member and a detection surface of the proximity sensor.   The dog is slidably inserted and supported in the guide tube that faces the head of the proximity sensor that has the detection surface at the tip, and the detection member is accommodated and arranged in the space formed by the guide tube and the dog together with the elastic body. The workpiece seating detection device according to claim 2, wherein the workpiece seating detection device is provided.   Instead of indirectly detecting the seating of the workpiece on the dog by the proximity sensor according to the movement of the dog when the dog abuts the workpiece, the dog is positioned on the workpiece positioned by sitting on the seating reference member. The contact sensor indirectly detects the seating / positioning state of the workpiece with respect to the seating reference member in accordance with the movement of the dog. The workpiece seating detection device described.   The work seating detection apparatus according to claim 6, wherein the seating reference member is disposed in proximity to the work seating detection apparatus itself. A locating device having a function of clamping a workpiece while positioning and supporting the workpiece by being inserted into a locating hole formed in the workpiece,
A locate pin having a workpiece seating surface on the base side and functioning as a positioning reference part;
A clamp arm built in the locate pin and clamped between the workpiece seating surface and the workpiece positioned by the locate pin by being driven forward and backward in a direction approaching and separating from the workpiece seating surface;
A direct acting actuator having a piston connected to the clamp arm to drive the clamp arm forward and backward;
The workpiece seating detection device according to claim 6 or 7,
With
The locating device, wherein the locating pin functions as a seating reference member of the workpiece seating detecting device. A workpiece seating detection method in which the proximity of the workpiece to the dog is indirectly detected by the proximity sensor according to the movement of the dog when the dog abuts the workpiece,
A detection member that functions as a proximity member while disposing a dog that can be moved toward and away from the detection surface on the front side of the detection surface of the proximity sensor and following the movement of the dog between the detection surface and the dog. And place
A workpiece seating detection method, wherein seating of a workpiece is detected in a state in which a displacement amount of a detection member capable of approaching and separating from the detection surface is restricted to be smaller than a displacement amount of a dog.

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