JP2014151393A - Work assembly apparatus and work assembly method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work assembly technology which enables a piston fitted with a connection rod to be visually inspected and integrated into the bore of a cylinder block.SOLUTION: A work assembly apparatus 10 consists of a work support mechanism 20 that moves a piston 11 and retains it at a prescribed position, a non-contact type distance meter 30 that measures a distance to the outer peripheral surface of the piston 11, a distance meter moving mechanism 40 that supports this non-contact type distance meter 30 and orbitally moves it, an acceptability judgement part 42 that makes acceptability judgement by comparing distance information acquired from the non-contact type distance meter 30 with basic data, an integration mechanism 50 that integrates the piston 11 into the bore 13 of a cylinder block 12, and a control part 60 that collectively controls the work support mechanism 20, non-contact type distance meter 30, distance meter moving mechanism 40, and integration mechanism 50.

Description

  The present invention relates to a work assembling technique in which a work, in particular, a piston having a connecting rod and upper and lower piston rings is incorporated into a bore of a cylinder block.

A cylinder block of the internal combustion engine is provided with a piston insertion hole called a bore, and a piston is inserted into the bore.
The piston is fitted with upper and lower piston rings. The piston ring is a ring with a part cut away so that the diameter can be reduced / expanded. This missing part is called an abutment.

  If the upper and lower joints are aligned (the phases are matched), the fuel gas blows through, which is not preferable. Therefore, the piston ring is fitted to the piston so that the phases of the upper and lower joints differ by about 180 °.

  At the stage where the upper and lower piston rings are fitted to the piston, the mutual positions of the upper and lower joints are visually confirmed by the operator. However, as part of labor saving, automated confirmation is recommended. Various inspection systems that can be automated have been proposed (see, for example, Patent Document 1 (FIG. 1)).

In FIG. 1 of Patent Document 1, a work (for example, a piston) (W) is placed on a rotary table (4) (the numbers in parentheses indicate the reference numerals described in Patent Document 1. The same applies hereinafter), and the vertical axis around Take a picture with the camera (7).
As described above, the joints of the upper and lower piston rings can be recognized in an image and the phases of the upper and lower joints can be examined.

After confirming the joint, a connecting rod is attached to the piston via a piston pin, and is transported in this state and inserted into the bore of the cylinder block.
Vibration and force are applied to the piston because the piston pin is driven when the connecting rod is installed. As a result, the piston ring may idle. In addition, the piston ring may idle during transportation.
Therefore, it is desirable to confirm the upper and lower joints immediately before insertion into the bore.

However, immediately before the insertion into the bore, the connecting rod is attached to the piston, and the connecting rod swings freely, so that it cannot be placed on the rotary table (4) of FIG.
If the structure of the rotary table (4) is modified so that the connecting rod can be fixed to the rotary table (4) together with the piston, the rotary table (4) becomes complicated and the cost of the apparatus increases, and the piston and connecting rod are attached and detached. Becomes troublesome, work efficiency deteriorates, and productivity decreases.
Therefore, it can be said that the piston with the connecting rod is difficult to inspect with the technique of Patent Document 1.

  While there is a demand for automation of assembly, a work assembly technique that can inspect a work such as a piston with a connecting rod and incorporate it into an assembly such as a bore of a cylinder block is required.

JP 2011-194498 A

  It is an object of the present invention to provide a work assembling technique capable of inspecting a work such as a piston with a connecting rod and incorporating it into an assembly such as a bore of a cylinder block.

The invention according to claim 1 is a workpiece assembling apparatus that inspects the appearance of a columnar or cylindrical workpiece, and incorporates the workpiece that has passed the inspection into an assembly.
A non-contact type distance meter that emits a light beam to the outer peripheral surface of the workpiece held in a predetermined position, receives reflected light, and measures the distance to the outer peripheral surface;
A distance meter moving mechanism for supporting and moving the non-contact distance meter;
A control unit for controlling the distance meter moving mechanism to turn the non-contact distance meter around the center of the workpiece as a turning center;
A pass / fail determination unit that performs pass / fail determination by comparing reference data given in advance and distance information obtained from the non-contact distance meter;
It is characterized by comprising a built-in mechanism that is incorporated into the assembly, for a work that is determined to be acceptable by the acceptance / rejection determination unit.

  The invention according to claim 2 is characterized in that the control unit controls the distance meter moving mechanism so that the non-contact type distance meter makes one turn around the workpiece.

  In the invention according to claim 3, the acceptance / rejection determination unit develops the distance information obtained from the non-contact type distance meter into the image data in the Y direction perpendicular to the X direction, with the direction around the workpiece as the X direction. It is characterized in that pass / fail judgment is performed.

  In the invention according to claim 4, the pass / fail judgment unit develops the image data with the direction around the workpiece set as the X direction and the direction orthogonal to the X direction as the Y direction, and obtained from the non-contact distance meter. Is converted into image data expressed in the color value of the portion, and pass / fail judgment is performed.

  The invention according to claim 5 is characterized in that the non-contact distance meter is a line sensor in which the light emitted from the light emitting unit can be regarded as a substantially line.

The invention according to claim 6 uses the workpiece assembling apparatus according to any one of claims 1 to 5, wherein the workpiece is a piston with a connecting rod and upper and lower piston rings, and the assembly target is A bore of a cylinder block, and a work assembly method for assembling the piston into the bore,
A distance measuring step of measuring the distance to the upper and lower piston rings by at least one round of the piston with the non-contact distance meter;
In the pass / fail determination unit, a pass / fail determination step for performing pass / fail determination on the phase of the joint of the upper piston ring and the joint of the lower piston ring from the distance information;
A diameter reduction step of reducing the diameter of the upper and lower piston rings to the outer peripheral surface with the built-in mechanism for the piston determined to be acceptable,
The assembly mechanism comprises a piston insertion step of inserting the piston into the bore.

  In the invention according to claim 7, the built-in mechanism has a diameter reducing claw for reducing the diameter of the piston ring and a pressing means for extruding the piston. In the diameter reduction process, the outer diameter of the piston ring is bored by the diameter reducing claw. In the piston insertion step, the piston is inserted into the bore by the pressing means while maintaining the reduced diameter state with the reduced diameter claw.

In the invention according to claim 1, the non-contact distance meter is turned around the stationary workpiece by the distance meter moving mechanism. Since the workpiece is not rotated, it is possible to inspect even if the workpiece is a piston with a connecting rod.
The workpiece that has been determined to pass is assembled into an assembly by an assembling mechanism.
In other words, a series of operations from appearance inspection to assembly is unmanned and automated, and productivity can be improved.

  In the invention which concerns on Claim 2, a non-contact-type distance meter is rotated only 1 rotation around the workpiece | work. Since it is not necessary to turn the machine several times, the inspection time can be shortened and further improvement in productivity can be expected.

  In the invention according to claim 3, the acceptance / rejection determination unit develops the distance information obtained from the non-contact type distance meter into the image data in the Y direction perpendicular to the X direction, with the direction around the workpiece as the X direction. Pass / fail judgment. In the Y direction, for example, the distance from the end face of the workpiece to the inspection target part can be confirmed, and it is possible to concentrate on this inspection target part and make a pass / fail determination. By combining with claim 2, the efficiency of inspection and the improvement of reliability can be achieved.

  In the invention according to claim 4, the pass / fail determination unit converts the distance information obtained from the non-contact distance meter into image data expressed as a color numerical value of the portion, and determines pass / fail. Pass / fail judgment by color is possible, and the pass / fail judgment work becomes easy.

  In the invention which concerns on Claim 5, a non-contact type distance meter is a line sensor which can consider the light irradiated from a light emission part as a substantially line. The line sensor is less expensive than a three-dimensional camera and signal processing is easy. Therefore, the device cost can be reduced.

In the invention according to claim 6, the non-contact distance meter is turned around the stationary piston by the distance meter moving mechanism. Since the piston is not rotated, the joint inspection of the piston ring is possible even when the connecting rod is attached.
The piston determined to pass is assembled into the cylinder block together with the connecting rod by the built-in mechanism.
In other words, in a piston with a connecting rod, a series of operations from phase inspection of the joint of the piston ring to assembly into the cylinder block is unmanned and automated, and productivity can be improved.

  In the invention according to claim 7, the outer diameter of the piston ring is reduced by the reduced diameter claw so as to be smaller than the inner diameter of the bore, and the piston is moved to the bore by the pressing means while maintaining the reduced diameter state by the reduced diameter claw. insert. There is no fear that the piston ring will be caught in the inlet of the bore, and the piston can be inserted into the bore more smoothly.

It is a perspective view of the workpiece | work assembly apparatus based on this invention. It is a basic lineblock diagram of a work support mechanism. It is a figure explaining a distance measurement process. FIG. 4 is a view taken in the direction of arrow 4 in FIG. 3. It is a figure explaining a pass / fail judgment process. It is another figure explaining a pass / fail determination process. It is sectional drawing of an incorporating mechanism. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 7. It is a 9-9 arrow line view of FIG. It is a figure explaining a diameter reducing process and a piston insertion process.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
In the embodiment, an example will be described in which “work” is a piston with a connecting rod and upper and lower piston rings, and “an assembly” is a cylinder block of an internal combustion engine. However, the workpiece is not limited to the piston, and the assembly target is not limited to the cylinder block.

  As shown in FIG. 1, the workpiece assembly apparatus 10 includes a workpiece support mechanism 20 that moves a piston 11 as a workpiece and holds it in a predetermined position, a non-contact distance meter 30 that measures a distance to the outer peripheral surface of the piston 11, A distance meter moving mechanism 40 that supports and moves the non-contact distance meter 30, a pass / fail determination unit 42 that performs pass / fail determination by comparing distance information obtained from the non-contact distance meter 30 with basic data, and a piston 11. The built-in mechanism 50 to be assembled into the bore 13 of the cylinder block 12, and the work support mechanism 20, the non-contact distance meter 30, the distance meter moving mechanism 40, and the control unit 60 that collectively controls the built-in mechanism 50.

  The non-contact distance meter 30 includes a light emitting unit 31 that emits laser light or infrared rays and a light receiving unit 32 that receives reflected light as one set, and a reflection surface (specifically, based on a change in the incident angle of reflected light. Measures the distance to the outer peripheral surface of the piston ring described later. A light sensor 31, a light receiver 32, a light emitter 31 </ b> B, a light receiver 32 </ b> B, a light emitter 31 </ b> C, and a light receiver 32 </ b> C provided with a plurality of sets in a row are called line sensors. By increasing the number of sets, distance information increases and the distance can be captured in a “line” shape.

  Another example of a line sensor (non-contact distance meter) is a single light-emitting unit that spreads laser light or infrared light in a band (line shape) by a light projection lens that can be spread in a band. A light receiving part, that is, a light receiving element (CMOS image sensor) is arranged in a clockwise or counterclockwise position as viewed from the light emitting part with the band (line) as an axis, and the reflected light is received as a light receiving element (CMOS). There is also a method in which light is incident on the surface of the image sensor and the distance to the reflecting surface is measured based on a change in the incident angle of the reflected light. This method can also capture distance information in a “line” shape.

  The non-contact type distance meter 30 may be a so-called three-dimensional camera, but is expensive and takes a long time for arithmetic processing because of much more processing information. On the other hand, if it comprises the light emission part 31 and the light-receiving part 32 like a present Example, it will become cheap and processing information will be little, and calculation time will become short.

  An upper piston ring 14 and a lower piston ring 15 are fitted to the piston 11 and a connecting rod 16 is attached. An oil ring is fitted below the lower piston ring 15, but this oil ring is omitted. The skirt portion 17 is gripped by the work support mechanism 20.

Details of each mechanism will be described below.
As shown in FIG. 2, the work support mechanism 20 includes, for example, a first robot 21, a pair of gripping claws 22, 22 attached to the tip of the first robot 21 so as to be openable and closable, and the gripping claws 22, 22. The two screw shafts 23 are screwed into the base of the first screw shaft 23, and the first actuator 24 rotates the two screw shafts 23. The grip claw 22 has a V-shaped groove 25, and a cushion material 26 is provided in the V-shaped groove 25.

Both screw shafts 23 are provided with a left male screw portion 27L and a right male screw portion 27R on the same axis, and when rotated by the first actuator 24, the same speed and the same speed as indicated by arrows (1) and (1). The grip claws 22 and 22 move at the timing to grip the skirt portion 17.
Since the connecting rod 16 is attached to the piston 11 via the piston pin 18, the connecting rod 16 (large end portion) swings up and down in the drawing with the piston pin 18 as the swing center.

  As shown in FIG. 1, the piston 11 in which the upper piston ring 14 and the lower piston ring 15 are fitted and the connecting rod 16 is attached is picked up by a first robot 21 from a stocker (not shown), It is carried right above the bore 13 and held in that position.

  As shown in FIG. 3, the distance meter moving mechanism 40 causes the non-contact distance meter 30 to face the outer peripheral surface of the piston 11. The distance meter moving mechanism 40 is preferably a robot that can be moved three-dimensionally while turning the non-contact distance meter 30.

Then, as shown in FIG. 4, the distance meter moving mechanism 40 causes the non-contact distance meter 30 to circulate around the piston 11 (arrow (2)). Preferably, the non-contact distance meter 30 is turned around the center O of the piston 11 as the turning center. The upper piston ring 14 has one abutment 14a.
During the lap, as shown in FIG. 3, the distance to the piston rings 14 and 15 is measured by the non-contact distance meter 30.

  In the case of a so-called three-dimensional camera (non-contact type distance meter), a lens with a known focal point is brought close to the object (work) inside the camera, and the object up to the object is determined by the position where the focal point is located. This refers to a method of measuring the distance, but the distance to the piston rings 14 and 15 can be accurately measured without being affected by the material and color of the piston rings 14 and 15.

An image of the distance information will be described with reference to FIG.
As shown in FIG. 5, in the upper piston ring, the distance once increased near 90 °. This increasing period is considered the upper joint (FIG. 4, reference numeral 14a).
In the lower piston ring, the distance once increased near 270 °. This increase period is considered the lower joint.

  The image of distance information used for pass / fail judgment is specified, for example, by specifying the position with the height direction of the piston 11 in FIG. 3 as the Y direction and the direction around the piston 11 in FIG. 4 as the X direction. Where the distance of the ring joint 14a is increased, for example, it is expressed by increasing the brightness (0 to 255), or, for example, it is expressed in red when the distance is close, and gradually as the distance increases. It is also possible to use distance data which is expressed in green and is expressed by gradually changing from green to blue as the distance further increases. That is, any data that can express a period in which the distance once increases or decreases in the piston ring may be used.

The reference data used for the pass / fail determination is determined as a relative phase θ = 180 ° ± 10 °, and is input in advance to the pass / fail determination unit (FIG. 1, reference numeral 42).
FIG. 5 is an image diagram (corresponding to a display image) in the X direction, and the relative phase is 270 ° −90 ° = 180 °. Since the relative phase 180 ° falls within the reference data 180 ° ± 10 °, the pass / fail determination unit determines “pass”. If the relative phase is less than 170 ° or greater than 190 °, it is determined as “fail”.
The reference data is an example and can be changed to an appropriate value (range).

  FIG. 6 is an image diagram (corresponding to a display image) in the Y direction, and the piston outline 44 is shown on the display 43. Arrow 45 indicates the general plane, arrow 46 indicates the position of the upper piston ring, and arrow 47 indicates the position of the lower piston ring. The upper ring 14a of the piston ring is displayed and can be confirmed.

Next, details of the built-in mechanism 50 will be described.
As shown in FIG. 7, the built-in mechanism 50 includes a second robot 51, a thick cylindrical main body 52 supported by the second robot 51, and a contraction that is movably attached to the lower portion of the main body 52. Diameter claws 53, 53, a claw moving mechanism 54 for moving these reduced diameter claws 53, 53, a bracket 55 extending upward from the upper surface of the main body 52, and a rod 56 supported by the bracket 55 extending downward. It consists of a pressing means 57 and a pressing pad 58 provided at the tip (lower end in the figure) of the rod 56.

  As shown in FIG. 8, a T-shaped groove 59 is provided in the main body portion 52. The upper part of the reduced diameter claw 53 is a T cross section 61. The T cross section 61 is fitted into the T-shaped groove 59. As a result, the reduced diameter claw 53 can move in the drawing front and back direction without falling.

As shown in FIG. 9, the claw moving mechanism 54 rotates, for example, a donut-shaped rotating plate 62, an oblique cam hole (or cam groove) 63 provided in the rotating plate 62, and the rotating plate 62 by a certain angle. The second actuator 64 is included.
A headed pin 65 extending from the reduced diameter claw 53 fits into the cam hole 62. When the rotating plate 62 is rotated clockwise in the drawing, the headed pin 65 is pushed by the cam hole 63. As described with reference to FIG. 8, the reduced diameter claw 53 is guided by the T-shaped groove 59 and moves toward the center.
As a result, in FIG. 9, the four reduced diameter claws 53 are simultaneously moved to the center of rotation and become a reduced diameter state.
As shown in FIG. 7, the rotating plate 62 is rotatably held by the main body portion 52, so there is no fear that it will come off the main body portion 52.

Next, the operation of the built-in mechanism 50 having the above configuration will be described.
In FIG. 10A, the diameter of the upper and lower piston rings 14 and 15 is reduced by the diameter-reducing claws 53 and 53 as indicated by arrows (3) and (3). The outer diameters of the piston rings 14 and 15 after the diameter reduction are smaller than the inner diameter of the bore 13, and a gap t corresponding to half of the difference between the outer diameter and the inner diameter is secured.

  Next, the gripping claws 22 and 22 are opened by arrows (4) and (4), and returned to the standby position. Thus, the piston 11 is transferred to the built-in mechanism 50. Since the gripping claws 22, 22, 22 do not get in the way, the piston 11 can be lowered together with the built-in mechanism 50.

As shown in FIG. 10 (b), the diameter-reducing claws 53 and 53 are lightly applied to the upper surface of the cylinder block 12 while the connecting rod 16 is inserted into the bore 13.
As shown in FIG. 10 (c), the piston 11 is pushed down through the pressing pad 58 by the pressing means 57 and the piston 11 is inserted into the bore 13. At this time, since the piston rings 14 and 15 are guided by the diameter-reducing claws 53 and 53 having a smaller diameter than the bore 13, the piston rings 14 and 15 are smoothly inserted into the bore 13. That is, there is no concern that the piston rings 14 and 15 are caught by the inlet of the bore 13.

  As described above, the distance measuring step is performed in FIGS. 3 and 4, the pass / fail determining step is performed in FIG. 5, the diameter reducing step is performed in FIG. 10 (a), and the piston is inserted in FIG. 10 (c). A process is performed. Since these processes are all unmanned and automated, it is possible to save labor and improve productivity.

In addition, this invention is suitable for the technique of incorporating the workpiece | work which is difficult to rotate like a piston with a connecting rod to an assembly like a cylinder block. If a workpiece | work exhibits a column shape or a cylindrical shape, a kind will be arbitrary.
The assembly target may be a housing, a case, or a body, and is not limited to a cylinder block.

  The present invention is suitable for assembling a piston having a connecting rod and upper and lower piston rings into a bore of a cylinder block of an internal combustion engine.

  DESCRIPTION OF SYMBOLS 10 ... Work assembly apparatus, 11 ... Piston, 12 ... Cylinder block, 13 ... Bore, 14 ... Upper piston ring, 14a ... Upper joint, 15 ... Lower piston ring, 16 ... Connecting rod, 20 ... Work support mechanism, 30 ... Non-contact distance meter, 31, 31B, 31C ... Light emitting unit, 32, 32B, 32C ... Light receiving unit, 40 ... Distance meter moving mechanism, 42 ... Pass / fail judgment unit, 50 ... Built-in mechanism, 53 ... Reduced diameter claw, 57 ... Pressing means, 60 ... Control unit.

Claims (7)

A work assembly device that inspects the appearance of a columnar or cylindrical work and incorporates the work that has passed the inspection into an assembly,
A non-contact type distance meter that emits a light beam to the outer peripheral surface of the workpiece held in a predetermined position, receives reflected light, and measures the distance to the outer peripheral surface;
A distance meter moving mechanism for supporting and moving the non-contact distance meter;
A control unit for controlling the distance meter moving mechanism to turn the non-contact distance meter around the center of the workpiece as a turning center;
A pass / fail determination unit that performs pass / fail determination by comparing reference data given in advance and distance information obtained from the non-contact distance meter;
A work assembling apparatus comprising a built-in mechanism for assembling the work to be assembled with respect to the work determined as acceptable by the acceptance / rejection determination unit.   2. The workpiece assembly apparatus according to claim 1, wherein the control unit controls the distance meter moving mechanism so that the non-contact distance meter makes one turn around the workpiece.   The pass / fail determination unit sets the direction around the workpiece as an X direction, and develops the distance information obtained from the non-contact distance meter into image data in the Y direction perpendicular to the X direction to determine pass / fail. The work assembly apparatus according to claim 1 or 2, wherein   The pass / fail judgment unit develops the image data with the direction around the workpiece as the X direction and the direction perpendicular to the X direction as the Y direction, and the distance information obtained from the non-contact type distance meter 3. The work assembling apparatus according to claim 1, wherein the acceptance / rejection determination is performed by converting the image data into a color numerical value.   5. The workpiece assembly apparatus according to claim 1, wherein the non-contact distance meter is a line sensor in which light emitted from the light emitting unit can be regarded as a substantially line. The workpiece assembly apparatus according to any one of claims 1 to 5, wherein the workpiece is a piston with a connecting rod and upper and lower piston rings, and the assembly target is a bore of a cylinder block, A work assembly method for assembling the piston in a bore,
A distance measuring step of measuring the distance to the upper and lower piston rings by at least one round of the piston with the non-contact distance meter;
In the pass / fail determination unit, a pass / fail determination step for performing pass / fail determination on the phase of the joint of the upper piston ring and the joint of the lower piston ring from the distance information;
A diameter reduction step of reducing the diameter of the upper and lower piston rings to the outer peripheral surface with the built-in mechanism for the piston determined to be acceptable,
A workpiece assembly method comprising: a piston insertion step of inserting the piston into the bore by the built-in mechanism. The built-in mechanism has a diameter reducing claw for reducing the diameter of the piston ring, and a pressing means for pushing out the piston,
In the diameter reducing step, the diameter of the piston ring is reduced by the diameter reducing claw so as to be smaller than the inner diameter of the bore,
The workpiece assembling method according to claim 6, wherein, in the piston insertion step, the piston is inserted into the bore by the pressing means while maintaining a reduced diameter state with the reduced diameter claw.

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