JPH0379136B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to, for example, automatic assembly equipment,
The present invention relates to an alignment device that can automatically perform alignment with respect to a fitting hole when fitting a member into the fitting hole.

[Prior Art] Generally, in an automatic assembly device, in order to insert a member into a predetermined fitting hole, the member and the fitting hole must be aligned with each other, in other words,
It is necessary to perform centering so that their central axes are located on the same straight line.

In order to align the member and the fitting hole with each other in this manner, a compliance mechanism is conventionally employed as shown in FIGS. 7A to 7C. In this compliance mechanism, the pin a is connected to the attached member b.
Even if their central axes are slightly deviated from each other, they can be reliably fitted into the fitting hole c formed in the fitting hole c.

Here, in the conventional compliance mechanism, as shown in the figure, a pin a is inserted into an insertion hole e formed in a holder d, and is sucked by a suction pipe f connected to a vacuum pump (not shown). hand,
It is held by a holder d. This holder d is fixed to a movable plate g. Two elastic leaf springs h are fixed to the movable plate g via a presser plate i and a screw j so as to be parallel to each other.

Further, an intermediate plate k is fixed to the other end of the leaf spring h mentioned above by a presser plate l and a screw j. Furthermore, this intermediate plate k has the above-mentioned 2
Two other mutually parallel leaf springs m are fixed via a presser plate n and a screw j in a state extending along a direction orthogonal to the leaf spring h.

A mounting base o is fixed to the other ends of these other two leaf springs m by a presser plate n and a screw j, and further, this mounting base o is fixed to an arm q by a screw p. Here, arm q is
It is attached to a movable arm (not shown) of a robot or the like in an automatic assembly device.

In the conventional compliance mechanism configured in this way, the movable plate g is in a state where it is easily movable along the left-right direction (x-axis direction) in FIG. 7A due to the deflection of the leaf spring h, and the intermediate plate Due to the deflection of the leaf spring m, k is in a state where it is easy to move along the direction (y-axis direction) perpendicular to the plane of the paper. In this way, the holder d fixed to the movable plate g is placed on a horizontal plane (x-y plane).
You will be able to move in any direction within the space.

Here, such a compliance mechanism is
The pin a, which is attached to the robot hand of the automatic assembly device and is held under suction by the holder d, is transferred to a predetermined position by the movement of the robot hand, and inserted into the fitting hole c formed in the member to be attached b. It works to make it fit in. Here, if the center axis of the pin a to be inserted and the center axis of the fitting hole c to be inserted are slightly misaligned, as shown in FIG. 7B, the opening of the fitting hole c The lower edge of the pin a comes into contact with a chamfered portion r that is chamfered on the edge.

As the robot arm q further descends from this contact state, the downward force exerted by the robot arm q is divided at the contact portion between the lower edge of the pin a and the chamfer r, and the force is applied to the pin a as shown in the figure. A lateral component force will act. As a result, the movable plate g is deflected in the lateral direction while remaining parallel to the intermediate plate k, and in this way, the pin a is displaced from the 7th C while maintaining its initial attitude and parallel state. As shown in the figure, it will be fitted into the fitting hole c.

In addition, as a conventional example of a centering device used in an assembly robot as an automatic assembly device, a robot body and a finger device are connected via a plurality of leaf springs, and the deformability of these leaf springs and The one that utilizes resilience is the Special Publication Act of 1983
It is disclosed in Publication No. 34932. Further, a structure in which a coil spring is used instead of a leaf spring and the robot body and the finger device are connected to each other by these coil springs is disclosed in JP-A-57-168840, JP-A-62-103990, and
It is shown in the specification of USP3824674.

Further, the alignment device needs to have a configuration that allows mutual displacement between the robot and the finger device and restores the robot and the finger device. USP4609325 specification,
US Pat. No. 4,179,783 and US Pat. No. 4,098,001 disclose a structure in which a bearing means and an elastic member allow displacement of a robot and a finger device and restore the robot to its original state.

[Problems to be Solved by the Invention] However, although conventional compliance mechanisms can perform alignment operations with a simple configuration, they have the following problems. It is.

In other words, in this conventional alignment device, if the center axis of pin a and the center axis of fitting hole c are parallel to each other but are simply shifted in the horizontal direction, compliance is reliably achieved. After absorbing this deviation, it is possible to allow the pin a to fit into the fitting hole c. However, if the center axis of the pin a and the center axis of the fitting hole c are diagonally misaligned, this conventional alignment device cannot handle the situation, and the holder d may be destroyed or the fitting operation may be difficult. A problem arises in that the process stops midway.

The alignment device described in such a conventional publication uses a spring that has directionality of displacement. For this reason, there is a restriction on the displacement direction of the finger device. Further, in the conventional alignment device, if an attempt is made to perform accurate alignment, the configuration becomes complicated.

In addition, the assembly work of goods by robots is carried out at high speed and with high precision within a unit of time.
It has its merits. Here, if such high-speed work is performed, a shift will occur in the assembly position of the object gripped by the finger device and the mating member. For this reason, the alignment device displaces the finger device relative to the robot arm to perform assembly work, and upon completion of this assembly work, the finger device is returned to its original position. . It is preferable that the time required for such a return operation of the finger device and for the finger device to come to rest is short. In particular, if this resting time takes a long time, a problem arises in that the next operation of the robot becomes unstable.

This invention has been made in view of the above-mentioned problems, and an object of the present invention is to reliably move the fitting member into the fitting portion even when the fitting member and the fitting portion are misaligned in an oblique direction. It is an object of the present invention to provide an alignment device having compliance that allows insertion.

[Means for Solving the Problems] In order to solve the above-mentioned problems and achieve the purpose, an alignment device according to the present invention includes a first shaft member extending and disposed along a predetermined axis. and a second shaft member disposed at a predetermined distance from the first shaft member along the predetermined axis of the first shaft member;
a plurality of support members disposed around the mutually opposing ends of the first and second shaft members so as to surround them; a first biasing member that biases the members so as to elastically press the first and second shaft members around opposing ends thereof; and a first biasing member that biases the first and second shaft members toward each other. a second biasing member that biases in a repulsive direction, and holds the second shaft member suspended from the first shaft member against the biasing force of the second biasing member. The present invention is characterized in that engaging portions are provided for the support member and the first and second shaft members, respectively.

[Function] In the alignment device configured as described above, compliance with respect to the tilt deviation with respect to the central axis, compliance with respect to deviation in a plane perpendicular to the central axis, and compliance with the direction of the central axis are determined. Each action is performed.

[Embodiment] Below, the configuration of an embodiment of the alignment device according to the present invention will be described in detail with reference to FIGS. 1 to 4B of the accompanying drawings.

FIG. 1 shows a state in which a hand portion 14 is attached to the tip of a robot arm 10, which constitutes a part of an automatic assembly device, via an alignment device 12 of this embodiment. The robot arm 10 is driven by a drive mechanism (not shown) to move freely in the left-right direction (x-axis direction), the direction perpendicular to the page (y-axis direction), and the vertical direction (z-axis direction) in the figure. It is something that

On the other hand, the hand portion 14 has a disc-shaped hand body 1.
6, and a holder 20 fixed to the lower surface of the hand main body 16 via a bolt 18. An insertion hole 24 is formed in the lower part of the holder 20, extending in the vertical direction, opening at the lower surface, and into which a pin 22 as a fitting member is inserted.

Here, a suction pipe 26 connected to a suction pump (not shown) is connected to the upper part of this insertion hole 24 so as to communicate therewith. By driving this suction pump, the inside of the insertion hole 24 is maintained in a negative pressure state, and the pin 22 is suctioned and held within the insertion hole 24 by this negative pressure.

Also, a fitting hole 28 into which this pin 22 is fitted
is formed on the substrate 30 as a member to be fitted. This substrate 30 is mounted horizontally on a base (not shown), and in this state, the fitting hole 28 is set to extend in the vertical direction. Note that a pin 22 is provided at the upper edge of this fitting hole 28.
In order to facilitate fitting, a tapered surface 32 is formed with a predetermined inclination with respect to the horizontal surface.

Here, the alignment device 12 of the above-mentioned embodiment
includes a compliance mechanism 34 disposed so as to have a central axis coaxial with the central axis of the robot arm 10. The alignment device 12 includes a disk-shaped mounting body 40 fixed to the lower end of the robot arm 10 via a bolt 38.

Here, the aforementioned compliance mechanism 34
In the normal state, when no external force is acting on the holder 20, the central axis of the robot arm 10 and the central axis of the holder 20 are elastically aligned with each other along the vertical direction. In addition, when an external force in a horizontal plane is applied to the holder 20, it is set so that it can be allowed to shift softly in a horizontal plane within a predetermined range in response to this external force.

The configuration of the compliance mechanism 34 that characterizes this embodiment will be explained below.

That is, this compliance mechanism 34 is attached to a mounting body 40 fixed to the lower end of the robot arm 10.
A first shaft member 34a is provided on the lower surface of the robot arm 10 and is integrally formed so as to be coaxial with the central axis of the robot arm 10 and protrude downward. On the other hand, a second shaft member 34b is fixed to the upper surface of the hand body 16 via a bolt 38 so as to be coaxial with the central axis of the holder 20 and project upward. These first and second shaft members 34a, 34b
The mutually opposing ends of are opposed to each other so as to be spaced apart from each other by a predetermined distance.

Here, outer flange portions 34c and 34d are integrally formed at the lower end of the first shaft member 34a and the upper end of the second shaft member 34b, respectively.

Further, this compliance mechanism 34
A plurality of support pins 34e are provided so as to simultaneously surround the opposing ends of the second shaft members 34a and 34b.

Each support pin 34d is integrally provided with outer flanges 34f and 34g at its upper and lower ends, respectively. In detail, these support pins 34d
Each of the outer flange portions 34f, 34g is formed from a cylindrical body having a radius considerably smaller than the radius of the first and second shaft members 34a, 34b, and the number thereof is set to six. There is.

Further, as shown in FIG. 2, the outer peripheries of the outer flanges 34c and 34d at the ends of the first and second shaft members 34a and 34b are provided with support pins 34e corresponding to the number of support pins 34e. , multiple V grooves 34m at equal intervals
is formed so as to extend along the vertical direction. A corresponding support pin 34e is fitted and supported in each V-groove 34m. In this way, the relative position of the second shaft member 34b with respect to the first shaft member 34a is elastically defined. In addition, on the outer peripheral surface of each support pin 34d except for the outer flanges 34f and 34g,
Annular cut grooves 34h are respectively formed.

These support pins 34e are connected to both shaft members 34
an outer flange 3 integrally formed at the upper end of the support pin 34e in a state surrounding the support pins 34e and 34b.
4f is the outer flange portion 3 of the first shaft member 34a.
4c from above, and is also formed integrally with the lower end of the support pin 34e.
The outer flange portion 34d of the second shaft member 34b engages from above. In this way, the hand body 1
6 is suspended from the mounting body 40 of the compliance mechanism 34 so as to be swingable around the central axis.

In addition, as shown in FIG. 2, these support pins 3
4e surrounds both shaft members 34a and 34b, similarly to the above-mentioned embodiment, these support pins 34e are placed in the first groove 34h so as to surround these support pins 34e all at once.
A ring-shaped biasing member 34i that biases the second shaft members 34a, 34b so as to elastically press against the circumferential surfaces of mutually opposing ends thereof is housed. In this embodiment, the biasing member 34i is formed from a finely wound ring-shaped coil spring.

On the other hand, as shown in FIG.
On the lower surface of a and the upper surface of the second shaft member 34b,
Recesses 34j and 34k are formed to face each other. These recesses 34j, 34k
A coil spring 34l is disposed with its upper end and lower end housed in each of the coil springs 34l. This coil spring 34l is connected to the first and second shaft members 34.
a and 34b are provided to bias them in the direction of separating them from each other.

Moreover, as shown in FIG.
2, when the robot arm 10 moves laterally at high speed, its inertia causes the second shaft member 34b to
A locking mechanism 38 is provided to prevent lateral deviation of the shaft member 34a relative to the first shaft member 34a. This lock mechanism 38 is connected to the first shaft member 3
4a includes a pair of cylinder chambers 38a formed at symmetrical positions with a recess 34j between them.

A piston member 38b is housed in each cylinder chamber 38a so as to be able to protrude downward. here,
Each piston member 38b has a coil spring 38
The piston member 38 is biased upward by the biasing force of the coil spring 38c.
The retracted position of the piston member 38b is defined at the position where the stopper member 38d integrally formed so as to protrude upward from the upper end of the cylinder chamber 38a comes into contact with the upper surface of the cylinder chamber 38a and stops.

Further, on the upper surface of the second shaft member 34b, a lock hole 38e into which the tip of the corresponding piston member 38b is fitted is formed at a position opposite to the tip of each piston member 38b. Here, a connecting pipe 38f connected to a pressurizing pump mechanism (not shown) is connected to a portion of each cylinder chamber 38a described above above the upper end of the piston member 38b.

Then, compressed air (pressurized air) is supplied from this pressurizing pump mechanism to the cylinder chamber 38 via the connecting pipe 38f.
each piston member 3 by being introduced into a
8b is pushed downward from the retracted position against the biasing force of the corresponding coil spring 38c, and biased to the lock position. In addition, in this lock position, the lower end of each piston member 38b is
It will fit into the corresponding lock hole 38e.
In this way, by activating the lock mechanism 38, the first and second shaft members 34a, 34
b are locked to each other in the lateral direction and move laterally in unison.

When the hand portion 14 is attached to the tip of the robot arm 10 via the alignment device 12 having the compliance mechanism 34 configured as described above, one fitting hole 28 formed in the substrate 30 , the insertion operation for inserting one pin 22 will be described below.

First, with the pin 22 held by the holder 20 under suction, the robot arm 10 is controlled to move by a control mechanism (not shown) so as to fit the pin 22 into the fitting hole 28 formed in the substrate 30.
That is, in this control mechanism, the fitting hole 2 is
8 on the x-y plane and the three-dimensional position of the robot arm 10, that is, the position information of the pin 22 to be inserted, are input, and the robot arm 10 is controlled based on these position information. The movement is controlled by the control operation of the mechanism.

Here, if this position information is accurate, the robot arm 10 is moved and driven according to the control contents of the control mechanism, and the fitting hole 28 is positioned according to the set value, the fitting hole 28 By moving the pin 22 directly above and then lowering it vertically, the pin 22 fits well into the fitting hole 28.
It will fit inside.

However, the positioning of the fitting hole 28 may not be accurate, resulting in a slight deviation from the set value in the If there is a slight deviation from the posture defined by, a deviation occurs in a so-called diagonal direction.

Here, on the robot arm 10 side, if the fitting hole 28 is formed with a diagonal deviation even though it is set accurately, the pin 2 that has been vertically lowered due to the lowering of the robot arm 10 may
2, as shown in FIGS. 1 and 3, its lower edge comes into contact with the tapered surface 32 of the fitting hole 28. Then, as the robot arm 10 further descends, the lower end edge of the pin 22 moves toward the tapered surface 3.
2 will receive a component force F directed in the horizontal direction.

Here, such horizontal component force F is expressed as pin 2.
2, this component force F is applied to the holder 2.
0, it acts on each second shaft member 34b of the compliance mechanism 34 via the hand main body 16. Therefore, when this component force F is not applied, the pair of upper and lower biasing members 34i elastically move the first and second shaft members 34a and 34b perpendicular to each other, as shown in FIG. 4A. From the axially aligned state, as shown in FIG. 4B, against the urging force of these urging members 34i,
By tilting the support pin 34e, the second shaft member 34b moves horizontally.

Further, in this compliance mechanism 34, the first and second shaft members 34a and 34b are set to be relatively swingable around the central axis, and as a result, such a fitting hole 28 Ya pin 2
Regarding the slope (α) from the central axis (z-axis) of 2,
Once it has compliance and is soft, the second shaft member 34b can tilt with respect to the first shaft member 34a. In this way, in this compliance mechanism 34, the fitting hole 2
8 and the pin 22 from the central axis are well absorbed, and the pin 22 is reliably fitted into the fitting hole 28.

In this way, the diagonal misalignment between the pin 22 and the fitting hole 28 is elastically absorbed by the misalignment and inclination of the first and second shaft members 34a and 34b in the compliance mechanism 34, and the pin 22 is The pins 2 are brought into the hole 28 so that their axes are aligned with each other, and as the robot arm 10 is lowered, the pins 2
2 will fit well into the fitting hole 28.

After the operation of fitting the pin 22 into the fitting hole 28 is completed, the drive of the suction pump (not shown) is stopped and the robot arm 10 is driven upward.
The holding state of the pin 22 in the holder 20 is released, and the hand portion 14 lifts up independently with the pin 22 released. Then, when the pin 22 is completely separated from the holder 20, the above-mentioned component force F no longer acts on the holder 20. As a result, the component force acting on the second shaft member 34b in the compliance mechanism 34 is eliminated, and the second shaft member 34b is From the biased state shown in the figure, the fourth
This results in a good return to the matching state shown in Figure A.

In this way, the alignment operation in the alignment device 12, in other words, the elastic deflection/return operation in the compliance mechanism 34 is completed.

On the other hand, since the above-mentioned coil spring 34l is provided, this compliance mechanism 34
will have compliance in the vertical direction (z-axis). Therefore, when the pin 22 is inserted into the innermost part of the fitting hole 28,
If the depth of the fitting hole 28 is shorter than the set value or if the pin 2
Even if the length of the coil spring 34l is long, deviations from these set values are reliably absorbed based on the elastic contraction of the coil spring 34l, and due to the so-called compliance regarding the z-axis, the robot arm 10
It will fit in well without applying any impact.

Further, as described above, the first and second shaft members 34a and 34b each have a V-groove 34m formed therein.
Since the support pin 34e is supported so as to be fitted into the first and second shaft members 34a, 34b,
The relative angular position at is elastically defined. As a result, compliance occurs when the angle in the horizontal plane (xy plane) is deviated. In this way, even if a deviation (θ) occurs around the z-axis,
The compliance corresponding to this deviation (θ) is
This compliance mechanism 34 can be fully utilized.

As detailed above, in the alignment device 12 in one embodiment, in addition to deviations in the x-axis, y-axis, and z-axis directions, deviations in the rotational direction around the z-axis (θ),
It deviates in response to the tilt (α) with respect to the z-axis with compliance, and when the component force based on the deviation in these diagonal directions is released, it reliably returns to the original aligned state. It is something that can be done.

It goes without saying that this invention is not limited to the configuration of the one embodiment described above, and can be modified in various ways without departing from the gist of the invention.

For example, in one embodiment described above, pin 2
2 has been described as being held in a vacuum-suctioned state in the insertion hole 24 formed in the holder 22, but
The mechanism is not limited to this, and may be a magnetic attraction using a magnet or a mechanical locking mechanism using a mechanical finger.

Further, in the compliance mechanism 34 of the above-described embodiment, a ring-shaped coil spring is used as the biasing member 34i. However, the present invention is not limited to such a configuration.
As shown in FIG. A as a first modification, a ring-shaped elastic rubber band 34n may be used.
In this case, compared to the case where a ring-shaped coil spring is used, each support pin 34c has a cut groove 34.
There is no need to form d.

Furthermore, as shown in a second modification example in FIG. 5B, by widening the width of this ring-shaped elastic rubber band 34n, it is possible to use only one elastic rubber band 34o instead of a pair of upper and lower elastic bands. Become.

Here, in the above-mentioned embodiment, the substrate 3
One fitting hole 28 is formed in the holder 2.
0, one pin 22 is inserted and held, and the case of a single shaft in which this pin 22 is fitted into the fitting hole 28 has been described. It is applicable not only to a two-shaft case in which two pins 22 inserted and held in a holder 20 are fitted into two fitting holes 28 formed in a substrate 30. It is possible.

That is, even in such a two-axis case, the sixth
As shown in Figure A, a line segment l ₁ connecting the centers of the two pins 22 and a line segment l ₂ connecting the centers of the two fitting holes 28
If they are deviated from each other while maintaining parallel states, the amount of deviation Δx along the x-axis direction and the amount of deviation Δy along the y-axis direction are different from each other when the respective pins 22 and The same value is obtained at the contact portion of the mating hole 28 with the tapered surface 32, and this can be ensured without rotation of the hand body 16 relative to the robot arm 10.

On the other hand, as shown in FIG. 6B, two pins 22
If the line segment _l1 connecting the centers of the two fitting holes 28 and the line segment _l2 connecting the centers of the two fitting holes 28 are deviated such that they intersect at a predetermined angle Δθ, The amount of deviation Δx and the amount of deviation Δy along the y-axis direction have different values at the contact portions between the respective pins 22 and the tapered surfaces 32 of the fitting holes 28, and the rotation of the hand body 16 with respect to the robot arm 10 is prevented. It will be accompanied. Even in such a case, the compliance mechanisms 34 and 36 in the alignment device 12 of this embodiment allow rotation of the hand body 16 relative to the robot arm 10 within a predetermined range, so that It can reliably deal with angular deviations.

Furthermore, the alignment device 12 of this embodiment is applicable not only to the two-axis fitting operation described above, but also to multi-axis fitting operations.

As described in detail above, in this embodiment, the alignment device 12 is capable of controlling deviations along the x-axis, y-axis, and z-axis, deviations (θ) in the rotational direction about the z-axis, and , have compliance with the tilt deviation (α) with respect to the z-axis, and will deviate softly in response to the deviation in the diagonal direction, and when the shear force based on this diagonal deviation is released, the , it is possible to return to the original, consistent state.

[Effects of the Invention] As detailed above, according to the present invention, the first shaft member extending and disposed along a predetermined axis;
A second shaft member disposed at a predetermined distance from the first shaft member along the predetermined axis of the first shaft member, and the first and second shaft members facing each other. A plurality of support members are disposed around the end portions so as to surround them, and are attached so as to surround these support members all at once, and these support members are attached to each other of the first and second shaft members. a first biasing member that biases the opposing ends so as to come into elastic pressure contact with each other; and a second biasing member that biases the first and second shaft members in a direction in which they repel each other. the supporting member and the first and second shaft members so as to suspend and hold the second shaft member on the first shaft member against the biasing force of the second biasing member. By means of an alignment device characterized in that an engaging portion is provided on each of the shaft members, compliance with respect to deviation in inclination with respect to the central axis, compliance with deviation in a plane perpendicular to the central axis, Each action is performed with respect to compliance in the direction of the central axis.

[Brief explanation of drawings]

Fig. 1 is a partially sectional front view showing the configuration of an embodiment of the alignment device according to the present invention; Fig. 2 is a sectional view taken along the - line in Fig. 1; The figure is a plan view showing a state of deviation in the x-y axis plane; FIG. 4A is a front view partially showing a state in which the first and second shaft members are aligned with each other;
FIG. 4B is a front view partially showing a state in which the first and second shaft members are shifted from each other in order to absorb the shift between the pin and the fitting hole; FIG. 5A is a first modification of one embodiment. Front view partially showing the configuration of the example; No. 5B
The figure is a front view partially showing the configuration of a second modification of one embodiment; Figure 6A is a top view showing the case where the misalignment is parallel in the case of two axes; Figure 6B is the case of two axes. FIG. 7A to FIG. 7C are front views showing the configuration and operation of a conventional alignment device. In the figure, 10... Robot arm, 12... Alignment device, 14... Hand section, 16... Hand body, 18... Bolt, 20... Holder, 22...
Pin, 24...Insertion hole, 26...Suction tube, 28...
...Fitting hole, 30... Board, 32... Tapered surface, 3
4... Compliance mechanism, 34a... First shaft member, 34b... Second shaft member, 34c; 34
d...Outer flange portion, 34e...Support pin, 3
4f; 34g...outer flange portion, 34h...cut groove, 34i...biasing member, 34j, 34k...
Recess, 34l...Coil spring, 34m...
V groove, 34n; 34o...Elastic rubber band, 36...
Bolt, 38...Lock mechanism, 38a...Cylinder chamber, 38b...Piston member, 38c...Coil spring, 38d...Stopper member, 38e
... Lock hole, 38f ... Connecting pipe.

Claims (1)

[Scope of Claims] 1. A first shaft member extending and disposed along a predetermined axis; and a first shaft member spaced apart from the first shaft member by a predetermined distance along the predetermined axis of the first shaft member. a second shaft member disposed in a manner similar to that of the first and second shaft members; a plurality of support members disposed around mutually opposing ends of the first and second shaft members so as to surround them; and these support members. a first biasing member that is attached to surround the first and second shaft members and urges the supporting members to come into elastic pressure contact around the opposing ends of the first and second shaft members; , a second biasing member that biases the first and second shaft members in directions that repel each other, and resists the biasing force of the second biasing member, and An alignment device characterized in that engaging portions are provided on the support member and the first and second shaft members, respectively, so as to suspend and hold the member on the first shaft member.