JPH0785854B2 - Follow jig - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a follower jig for an assembling machine.

[Prior Art] Conventionally, when assembling a part A into a part B in an assembling machine, for example, the part A is grasped by a hand attached to a robot or the like, the part B is positioned by a jig or the like, and the part A is part B. Assemble to. This situation will be described with reference to FIG. FIG. 5 is a vertical cross-sectional view when the assembly direction is taken in the vertical direction along the drawing, (1) is a part A having a round shaft, and (2) is a part B to which the part A (1) is assembled.
There is a hole in it. (5) is the center line of the part A (1) and the part B (2) that are substantially parallel to the assembly direction. Part A
(1) is held by a hand (3) attached to a robot or the like (not shown), and the component B (2) is positioned by a jig (4). Part A (1) and Part B (2)
Are chamfered (1-a) and (2-a).
Now, the part A (1) is held by the hand (3) attached to the robot, etc., and the part B (2) is the center of the parts A (1) and B (2) by the jig (4). Since the line (5) is positioned so as to substantially coincide with each other, if the robot or the like is moved parallel to the direction of the center line (5), the part A
(1) will be assembled into the part B (2). The situation is illustrated in order in FIG. 6 and FIG. FIG. 6 shows that the robot or the like moves parallel to the center line (5) and the part A (1)
FIG. 7 is a vertical cross-sectional view when the assembly is started to be assembled into the component B (2), and FIG. 7 is a vertical cross-sectional view showing a state when the assembly is completed. The parts A (1) and B (2) are usually fit with or without clearance. 8 and 9 are enlarged longitudinal sectional views showing the fitting relationship between the parts A (1) and B (2) in FIG. FIG. 8 shows the case of a fit with a clearance, and there is a clearance (6) between the parts A (1) and B (2). FIG. 9 shows the case of a fit with no clearance, where there is no clearance between the parts A (1) and B (2), and there is a interference (7). Specifically, part A (1)
9 is larger than the hole diameter of the part B (2), and in the state of FIG. 9, the part A (1) is deformed in the direction of decreasing the diameter and the part B (2) is increased in the direction of increasing the diameter. It is transformed. Now, the hand (3) that holds the component A (1)
The robot and the like attached repeatedly move to the positions shown in FIG. 5 according to the assembly program. Normally, the repeatability of a robot is about ± 0.03mm for general industrial use. This means that the position accuracy of the component A (1) when sandwiching the component A (1) of the hand (3) cannot be further reduced. Further, the part B (2) is positioned by the outer shape,
Most simply, even if the component B (2) is integrally machined, the positional accuracy of the hole with respect to the outer shape is about ± 0.02 mm assuming general machining. Most of the parts handled by the assembling machine are not machined integrally, but rather, the combination of a plurality of parts is overwhelmingly common. Therefore, for example, when the component B (2) is a combination of a plurality of components, the positional accuracy of the hole with respect to the external shape of the component is expected to be worse than the above-described accuracy. After all, in general assembly work, the center line (5) shown in FIG.
Does not completely match the parts A (1) and B (2). This is a serious problem for assembly machines,
For example, assuming that the components shown in FIG. 5 including the robot and the like are completely rigid, it is a fit with a clearance between the parts A (1) and B (2), and
FIG. 8 shows the amount obtained by combining the positional accuracy of (1) and the part B (2), that is, the deviation between the center line (5) of the part A (1) and the center line (5) of the part B (2). Unless the clearance (6) is less than or equal to (6), the parts A (1) and B (2) cannot be assembled. The situation is shown in FIG. FIG. 10 is a vertical cross-sectional view showing a state where the center lines (5) of the parts A (1) and B (2) are displaced from each other. When the deviation (8) shown in FIG. 10 is the above-mentioned deviation and the mechanical system is a completely rigid body, it is impossible to push the part A (1) into the hole of the part B (2) from the state of FIG. Obviously it is impossible. Therefore, when performing the work as shown in FIG. 5 in the assembling machine, efforts are made to keep the width of positional accuracy of the parts A (1) and B (2) below the clearance (6) in FIG. Done. Moreover, in reality, even if the mechanical system is a completely rigid body, even if it falls into the situation shown in Fig. 10, the assembly work can be continued by bending somewhere in the mechanical system, resulting in assembly. Can
Even in that case, if the deviation (8) in FIG. 10 is extremely large, the assembly cannot be performed. At the maximum, the chamfer (1-a) of the part A (1) and the chamfer (2-a of the part B (2) are the same. ) And is the 10th
Only the amount of slippage that fits the figure and that can slide is allowed. The same applies to the press-fitting work shown in FIG.

As described above, when assembling two parts with the assembling machine in which the situation shown in FIG. 10 may occur, somewhere in the mechanical system always bends. The RCC (Remote Center Complianc) is a device that actively generates this deflection.
e) It is called a device. The RCC device will be described below with reference to FIGS. 7, 8 and 9 in combination with the latest parts supply technology overview published by the Industrial Technology Service Center Co., Ltd. FIG. 11 is a vertical cross-sectional view parallel to the assembly direction with the RCC device mounted between the hand (3) and the robot etc. of FIG. 5, and the pin (9) incorporated in the hole (10) is It is gripped and positioned by the hand side plate (12) and connected to the base (15) via the compliance unit (13) and the arm side plate (14). The base (15) is a base for mounting on a robot or the like. The compliance unit (13) is soft to the movement on the plane including the flexure (13-a) in FIG. 11 (strictly speaking, the attachment point of the compliance unit (13) to the arm side plate (14) is the center. Although it is a motion on a spherical surface, it can be realistically approximated to a plane.) It has a rigid property in the longitudinal direction at a right angle to it. First
FIG. 12 shows the force acting on the pin (9) when the pin (9) and the hole (10) shown in FIG. 7 are displaced, and the chamfer (11) on the hole (10) The contact force (16) acts on the contacting pin (9) at right angles to the chamfer (11), and the contact force (16)
Is decomposed into an axial force (17) and a horizontal force (18).

Since the compliance unit (13) in FIG. 11 is soft in the direction of flexure (13-a) and rigid in the longitudinal direction at a right angle to it, the robot etc. moves downward in the drawing from the state of FIG. When the state shown in Fig. 12 is reached, the horizontal force (1
The 8) allows the compliance unit (13) to perform flex assembly. FIG. 13 is a vertical cross-sectional view showing the state after the assembly is completed, and the compliance unit (13) in FIG. 13 is deflected by the displacement (19). After all, the RCC device is a device that elastically supports an object and translates when a force acts on the object according to a component force in a direction perpendicular to the assembly direction of the force. Actually, RC
C has another characteristic that when a moment acts on the object, the object makes a rotational motion around a certain point.In the present invention, since there is no relation with respect to that point, it is omitted, and only the translational motion is performed. Is a problem. One specific example of the compliance unit (13) is shown in FIG. First
Fig. 14 is a side view of the compliance unit (13) alone. In the side view of (22) and (23), the rubber (21) and metal shim (20) are laminated so that they are stiff in the vertical compression direction. In addition, it has a soft structure in the shearing direction to the left and right of the drawing. The base (22) and the base (23) are attached to the hand side plate (12) and the arm side plate (14) shown in FIG.

By attaching the RCC device described above to the hand (3) of FIG. 5, the misalignment between the pin (9) and the hole (10) is well absorbed, and the assembly becomes easy.

[Problems to be Solved by the Invention]

The RCC device has an excellent mechanism and can be applied to many assembling machines, but in the case of special assembling, problems may occur. The horizontal force (1
When 8) is very small, it is difficult to apply with conventional RCC device. In the structure shown in Fig. 14, when the rigidity in the compression direction is increased, the rigidity in the shear direction is also inevitably increased.For example, press-fitting a perforated part on the shaft to strictly control the press-fitting depth If the directional force (18) is several tens of grams and the force input is several kilograms, the compliance unit (1
Design and production of 3) will be difficult. This is because, in order to strictly control the press-fitting depth, the compliance unit (1
It must be given to the rubber (21) of 3), otherwise the press-fitting depth will change too much with respect to the change in the press-fitting force. Rubber (21) of the compliance unit (13) at that time
This is because the spring constant in the shearing direction of the laminated part must be in units of grams / mm. In the present general materials (including rubber), no one has such characteristics. In reality, there is a compromise to some extent, and in many cases, the adoption of RCC devices is postponed. Further, considering that most of the RCC devices are mounted on a robot or the like, it is disadvantageous to make the spring constant in the breaking direction of the compliance unit (13) low. This is because the robot or the like usually moves in the direction perpendicular to the assembly direction before moving to the actual assembly work (the parts must be transported from the supply device to the assembly position), and the acceleration motion Must exist. When acceleration is applied to the component, inertial force naturally acts, and if the direction of acceleration is the shearing direction of the compliance unit (13), the hand side plate (12) and pin (9) in FIG. 11 act as inertial force. It will translate in the direction you do. In terms of results,
The hand side plate (12) and the pin (9) vibrate, and if the vibration is severe, not only the assembling work is impossible, but also the pin (9) is dropped. If the operation of the robot or the like is delayed to avoid it, the productivity will decrease. There is another problem. FIG. 15 is a top view showing a displaced state of the RCC device, and FIG. 11 is seen from the assembly direction. The pin (9) and the arm side plate (14) are shown with a dotted line. Since the compliance unit (13) is soft in the shearing direction, when the base (23) is fixed and a shearing force is applied to the base (22) in FIG. That is, in the state shown in FIG. 13, the compliance unit (13) is bent to the right in the drawing, but the left one of the two compliance units (13) is bent to the front in the vertical direction of the drawing, and the right one is drawn to the drawing. It means that it can bend vertically to the other side of the paper. FIG. 15 is a top view showing the displacement state of the RCC device, the hand side plate (12).
Is rotating (24) around the center of the pin (9). This narrows the range of use of RCC devices. For example, if an RCC device is used to assemble a clock hand into a watch, if the hands are assembled by rotating as described above, the hour hand points at 12:00, but the minute hand
It means that there is a risk that a watch like 10 minutes will be produced.

[Means for Solving the Problems]

As means for solving the above-mentioned problems, a coupling having a torque transmission function, a base for mounting the coupling with one end as a fixed end when viewed along the torque transmission shaft of the coupling, and the coupling In a tracing jig constituted by a jig attached to the free end with the opposite side when viewed along the torque transmission shaft of the fixed end as the free end, the base and the jig are The present invention provides a tracing jig having a surface parallel to a plane orthogonal to an axis and facing each other with a slight clearance therebetween.

[Action]

Unlike the conventional RCC device, the present invention is not mounted between a robot or the like and a hand, but is separately arranged and used. A coupling that has a torque transmission function is a mechanical element that has the function of connecting a drive shaft and a driven shaft and transmitting torque. It can transmit torque by absorbing the drive shaft, driven shaft, eccentricity, and axial displacement that should be connected. It is a feature, and by its nature, it is soft in the direction perpendicular to the rotation axis of the coupling and in the axial direction, and it is extremely resistant to torsion moments. This state is specifically shown in Fig. 16, (25) is a coupling (26).
Is a drive shaft connected to the end of the coupling, the rotating direction is (30), and (27) is the driven shaft rotated direction (31). The center line (28) of the drive shaft is offset from the center line (29) of the driven shaft by the amount of eccentricity (43). Now, one end of the coupling is fixed to the base as a fixed end, and the component is positioned by the jig attached to the free end opposite to the fixed end of the coupling. Parts are grasped by a hand attached to a robot or the like and assembled into parts positioned by the jig. For simplification of explanation, the jig (4) shown in FIG. 5 is a jig constituting the present invention. When the part falls into the situation of Fig. 10, the force shown in Fig. 12 acts on the part. In Fig. 12, only the force acting on the pin (9) is shown, but the force of the hole (10) It must also exert a force on the open parts, which have the same magnitude but opposite directions. Therefore, the component B (2) is subjected to a force having the same magnitude as the horizontal force (18) shown in FIG. Part B
Since (2) is positioned by the jig (4) and the jig (4) is fixed to the free end of the coupling, a force in the direction opposite to the horizontal force (18) acts on the coupling. The assembly can be performed by bending it in the direction perpendicular to the assembling direction and in the left direction of the drawing in FIG. Further, since the coupling is for torque transmission and the fixed end is fixed to the base, the free end of the coupling does not rotate with respect to the base, and any force acts on the jig (4). However, if it is within the torque load capacity range of the coupling,
The jig (4) and the base never rotate relative to each other.

〔Example〕

Preferred embodiments of the present invention are shown in FIGS. 1, 2, 3, and 4.
This will be described using the figure. The assembly work in which the present invention is most effective is the assembly of the hands of the timepiece into the timepiece. Assembled from Fig. 4 with the hands and watch, viewed from the right angle,
In (32), the axis (32-b) into which the needle is to be press-fitted is a minute axis concentric with the axis (32), and (32-c) is a second axis concentric with the axis (32). (33) is the watch body, (34) is the hands, (35) is the hole of the hands and the center line of the shaft (32). FIG. 2 is a cross-sectional view showing the relationship between the hands, hands, and timepiece as viewed in the same direction as in FIG. As mentioned above, the assembly is easy if the center line (35) is aligned with the hole (34-a) and the axis (32), but this is not the case. Therefore, the combined amount of the positioning accuracy of the hand (34) (finally, the positioning accuracy of the hole (34-a)) and the positioning accuracy of the watch body (33) is greater than the width of the chamfer (32-a). The condition that the needle (34) can be pressed into the shaft (32) is that the mechanical system bends with a small force that does not hinder the assembly. However, despite the fact that the watch body (33) is a composite of many parts, it must be positioned by the outer shape, and the positional accuracy of the shaft (32) with respect to the outer shape is not very good. The needle (34) is positioned as shown in Fig. 2. In Fig. 2, the needle (34) is guided through the hole (34-a) by the pin (37), and the pin (37) is attached to the hand (36). It can be moved vertically in the drawing. It cannot rotate. The hole (38) is concentric with the outer diameter of the pin (37). A chamfer (38-a) is attached to the mouth of the hole (38) and a chamfer (37-a) is attached to the outer diameter. There is. There is a clearance (37-b) between the pin (37) and the needle (34). The clearance (37-b) is necessary when the needle (34) is picked up by the hand (38). Further, the tip of the pin (37) is provided with a chamfer (37-a) so that the pin (37) can be easily fitted in the hole of the needle (34).
Therefore, the positional accuracy of the hole (34-a) of the needle (34) is the sum of the clearance (37-b) and the repeatability accuracy of the robot or the like, which is not very good. After all, the combined amount of the positional accuracy of the shaft (32) and the positional accuracy of the hole (34-a) is the shaft (32).
The width of the chamfer (32-a) may be larger, and some assembly is required for assembly. The hole (38) concentric with the pin (37) is made slightly larger than the minute axis (32-b), and the chamfer (38-a) is opened at the mouth of the hole (38). The mechanism of assembly is the pin (3
7) fits on the minute axis (32-b) by chamfering (38-a), and the pin (37) and the center of the axis (32) are substantially aligned. Next, the band (36) is lowered by the movement of a robot or the like, and the pin (37) can slide, so that the pin (37) hits the tip shaft (32) and is caught in the hand (36), and the needle (34). ) Hole (34-a) is chamfered on the shaft (32) (32
-A) and the needle (34) chamfers the shaft (32) (32-
When the hand (36) is lowered further by slipping a), the needle (34) is pressed into the shaft (32). FIG. 3 is a cross-sectional view showing this state, and the dotted line shows the state in which the needle (34) is press-fitted. Now, in the mechanism of this assembling work, it becomes necessary to bend somewhere in the mechanical system in order for the pin (37) to follow the split axis (32-b). Conventional RCC
When the device is adopted, the horizontal direction of the pin (37) is at most several tens of grams, which fits the above-mentioned problems of the conventional technology. Then RC on the side of the watch body (33)
Why not install a C device? This is also a problem with the conventional technology, that is, the problem of press-fitting depth control, and the watch body (33).
It won't work unless you take steps to prevent it from rotating.

Therefore, the present invention is applied. FIG. 1 is a sectional view showing the most basic constitution of the present invention. (39) is a coupling, (40) is a base for fixing one end of the coupling (39), and (41) is a jig for positioning parts. The jig (41) is for positioning the timepiece body (33) with its outer shape. The coupling (39) connects the base (40) and the jig (41) in a posture capable of transmitting torque in the vertical direction in FIG. 1 (the same posture as shown in FIG. 12), and its center line is (4
2). Due to the nature of the coupling, the end of the jig (41) of the coupling (39) can bend in the plane perpendicular to the center line (42) when a force is applied to the end. Therefore, the jig (41) can also be displaced in the plane perpendicular to the center line (42). A small clearance (not shown) is provided between the base (40) and the jig (41) so that frictional resistance is not added to the displacement of the jig (41). The coupling can be slightly displaced in the direction along the center line (42). Now, when transitioning from the state shown in FIG. 2 to the state shown in FIG. 3, FIG. 12 should pass through the state as seen upside down. At that time, the horizontal force (18) shown in Fig. 12 should act on the shaft (32), and the horizontal force (18) acts on the watch body (33) and is transmitted to the jig (41). , The coupling (39) can be flexibly assembled. When the coupling (39) begins to flex, the axial force (17) shown in FIG. 12 is small, so the clearance between the base (40) and the jig (41) still exists, and the needle (34) When the coupling (39) starts to be pressed into the shaft (32), the coupling (39) will move to the center line (4
The clearance is removed along with 2), and the jig (41) and the base (40) receive the force input. Also,
Due to the nature of the coupling, the jig (41) does not rotate around the center line (42) even if the coupling (39) is displaced perpendicularly or parallel to the center line (42), and the base (40) The angle around the center line (42) of the jig (41) does not change.

〔The invention's effect〕

Since the present invention is configured as described above, it has the following effects.

When the horizontal force (18) shown in Fig. 12 is small,
Can be used in place of the RCC device. It can be used in place of an RCC device in a two part assembly where the parts must not rotate relative to each other. When it is used for press-fitting work, the press-fitting force is ultimately received by the jig and base, which are rigid, so the press-fitting depth can be strictly controlled. Since it is not attached to a robot or the like, it is not affected by acceleration or vibration of the robot or the like, and the robot or the like can be operated at high speed, resulting in high productivity.

[Brief description of drawings]

Fig. 1 Longitudinal section of the embodiment (33) …… Watch body, (34) …… Hand (39) …… Coupling, (40) …… Base (41) …… Jig, (42) …… Center line Fig. 2 Longitudinal section showing the relationship between needle (34) and hand (34) …… Needle, (36) …… Hand (37) …… Pin, (37-a) …… Chamfer (37) -B) ... clearance, (38) ... hole (38-a) ... chamfer Fig. 3 Longitudinal sectional view showing before and after press-fitting of needle (34) Fig. 4 Relationship between needle (34) and clock Vertical sectional view (32) …… axis, (32−a) …… chamfer (32−b) …… minute axis, (32−c) …… second axis (33) …… watch body, (34) ...... Needle (34-a) ...... Hole, (35) ...... Center line Fig. 5 Vertical cross-sectional view before assembly of two parts (1) ...... Part A, (1-a) ...... Chamfer (2) ...... Part B, (2-a) …… Chamfer (3) …… Hand, (4) …… Jig, (5) …… Center line Fig. 6 Vertical sectional view just before assembly of two parts (5) …… Center line Fig. 7 Vertical sectional view just after assembly of two parts (5) …… Center line Fig. 8 Vertical sectional view showing fitting state (6) …… Clearance Fig. 9 Longitudinal section showing fitting condition (7) …… Night interference Fig.10 Longitudinal section immediately before assembly of two parts (5) …… Center line, (8) …… Displacement Fig.11 Addition of RCC device Vertical cross-sectional view of the hand part and parts that were removed (9) …… Pin, (10) …… Hole, (11) …… Chamfer (12) …… Hand side plate (13) …… Compliance unit (13- a) …… Deflection (14) …… Arm side plate, (15) …… Base Fig. 12 Longitudinal section showing the force acting on the pin (9) (16) …… Contact force, (17) …… Axial direction Force (18) …… Horizontal force Fig. 13 Longitudinal section showing displacement state of RCC device (19) …… Displacement Fig. 14 Comply Side view of ans unit (13) (20) …… Metal shim, (21) …… Rubber (22) …… Base, (23) …… Base Fig. 15 Top view showing displacement of RCC device (9) ...... Pin, (12) …… Hand side plate (13) …… Compliance unit (14) …… Arm side plate, (24) …… Rotation Fig. 16 Vertical section of coupling (25) …… Coupling , (26) …… Drive shaft (27) …… driven shaft, (28) …… center line (29) …… center line, (30) …… rotation (31) …… rotation, (43) …… eccentricity

Claims (1)

[Claims] Claim: What is claimed is: 1. A coupling having a torque transmitting function, a base on which the coupling is mounted with one end of the coupling as viewed along a torque transmitting shaft as a fixed end, and torque transmitting at the fixed end of the coupling. In a tracing jig constituted by a jig attached to the free end with the opposite side when viewed along the axis as a free end, the base and the jig are planes orthogonal to the axis of the coupling. A tracing jig having parallel surfaces and facing each other with a slight clearance.