JPH0575514B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic tool changer, and more particularly, the present invention relates to an automatic tool changer.
unit and at least one second unit to which various tools can be attached;
The present invention relates to an automatic tool changer configured to releasably couple a unit to a first unit.

[Conventional technology]

The automatic tool changer with the above configuration uses a coupling device that connects the robot side unit and tool side unit in a separable manner, but the conventionally known coupling device is mainly of the configuration shown in Fig. 8. It was hot.

That is, a tapered hole 103 is formed in the side wall of a recess 102 provided in a unit 101 on the robot side,
A steel ball 104 is fitted into the tapered hole 103 so that its inner end can protrude into the depression 102, and a steel ball holder 105 is provided on the outside of the steel ball 104 so as to be movable up and down. The steel ball retainer 105 is constantly urged downward by a compression spring 107 provided in an upper chamber 106, and
When compressed air is supplied to the cylinder, it moves upward.

When the steel ball holder 105 descends to the position shown, its inner end surface presses the steel ball 104 inward,
The inner end of the steel ball 104 protrudes from the side wall of the recess 102. When the steel ball holder 105 rises, the steel ball 10
4 has been moved outward and does not protrude from the side wall of the recess 102.

The tool side unit 110 is provided with a substantially cylindrical engagement protrusion 111 at a position corresponding to the recess 102 of the robot side unit 101, and the steel ball 1 is inserted into a notch 112 formed near the tip of the engagement protrusion 111.
04 is inserted and engaged.

Note that 113 is an O-ring for sealing.

When combining and integrating both units 101 and 110, first supply compressed air from the port 108 to the chamber 109 below, raise the steel ball holder 105, and move the steel balls 104 outward. , robot side unit 101 and tool side unit 110
The opposite surfaces of the tool side unit 1 are brought into contact with each other.
The engaging protrusion 111 of 10 is connected to the robot side unit 10.
1 into the recess 102. Next, lower chamber 1
When the compressed air is discharged from 09, the steel ball holder 10
5 descends, the steel ball 104 is pushed inward and engages with the notch 112 of the engagement protrusion 111. In this way, both units 101 and 110 are combined and integrated. In the conventional coupling device, the steel balls 10
4 and the engaging protrusion 111, both units 1
01 and 110, so when a large tool weighing about 100 kg is attached, such as a spot welding unit, the engagement protrusion 111
A very large contact pressure is generated at the contact point between the steel ball 104 and the steel ball 104, and at the contact point between the steel ball holder 105 and the steel ball 104. As a result, the contact portion is depressed, and the steel ball 104 bites into the depression, which tends to cause malfunctions, particularly the inability to separate the two units 101 and 110.

Moreover, in this coupling device, both units 101,
110 is located far inside its outer periphery (closer to the center axis), it is extremely vulnerable to the moment acting at right angles to the engagement protrusion 111 of the tool side unit 110, and both units 101,
There is a problem that the 110 easily tilts or wobbles. The only way to solve this problem is to make the engaging protrusion 111 thicker, but this inevitably increases the overall size of the device, making it difficult for this type of device to be used in robots that require small size and light weight. A coupling device is also disclosed in Japanese Unexamined Patent Publication No. 63-30183.

The coupling mechanism between the first unit (carrying member) and the second unit (coupling flange) disclosed in this publication basically consists of a movable meshing device and a clasp device. Specifically, this coupling mechanism is made to swing by the vertical movement of a piston provided in the first unit, and the output end thereof moves in and out (lateral) directions due to the swinging. a crank lever, and is provided on the first unit and is connected to the inside and outside (laterally) by the output end of the crank lever.
The device is equipped with a meshing tooth that can be moved in the direction of the meshing tooth, and a meshing appendage that is provided on the second unit side and has a horizontal recess into which the outer end of the meshing tooth is inserted and removed, The second unit is connected to the first unit in a hanging manner by inserting the end into the horizontal recess.

However, in this coupling mechanism, as the number of connections and separations between the first unit and the second unit increases, the upper and lower surfaces of the meshing teeth and the upper and lower wall surfaces constituting the horizontal recesses of the meshing appendage wear out. As it is, the second unit becomes loose with respect to the first unit. Therefore, it has a fatal defect of poor positioning accuracy.

[Problem to be solved by the invention]

This invention was made in view of the above-mentioned circumstances, and its purpose is to provide a tool that has a very large locking force and that can be operated by attaching a tool that weighs several hundred kilograms. There is no risk of tools falling or vibration during movement, or malfunctions when connecting and separating both units, and the automatic tool changer is highly rigid against external forces perpendicular to the central axes of both units. It is about providing.

Another object of the present invention is to provide an automatic tool changer in which the coupling device is not easily damaged even when a heavy tool is attached and operated, and is highly durable. It is an object of the present invention to provide a coupling device for an automatic tool changer that does not cause backlash between units and has excellent positioning accuracy.

[Means to solve the problem]

This invention comprises a first unit 2 connected to operating means of a robot and at least one second unit 3 to which various tools can be attached, and one second unit 3 is connected to the second unit 3 by means of a coupling device. 1
In the automatic tool changer configured to be separably connected to the unit 2, the coupling device rotates around a rotation axis provided in one of the units 2 and 3. The cam 15 and an engagement pin 46 provided on the other unit and capable of being engaged with the cam 15 when both the units 2 and 3 are in contact with each other.
and a cylinder 17 for driving the cam 15.
The cam 15 includes an engaging portion 15 formed in a curved surface such that the distance from the rotation axis gradually changes.
a, and its engaging portion 15a is at a distance from the rotation axis to the point of contact between the engaging pin 46 and the cam 15 when the contact surfaces of both units 2 and 3 are in contact with each other. It includes a portion equal to the distance from to the rotation axis and a portion larger than the distance, and by rotating the cam 15 and bringing the engaging portion 15a into contact with and pressing the engaging pin 46. , both units 2 and 3 are connected.

The cylinders 17 and the cams 15 are arranged in three cylinder accommodating chambers 12 arranged at equal intervals around the central axis of the one unit, and the engagement pins 46 are arranged in three cylinder housing chambers 12 arranged at equal intervals around the central axis of the one unit. There may be three arranged at equal intervals around the central axis.

Further, it is preferable that the cam 15 is made of a substantially fan-shaped plate, and that the engaging portion 15a thereof is provided in an arc-shaped portion.

The position of the rotating shaft of the cam 15 causes at least a portion of the force in the direction of separating the units 2 and 3 that are in contact to increase the pressing force of the cam 15 against the engagement pin 46. It is preferable to set the position so that it acts in the direction.

[Effect]

With the above structure, when each cam 15 is rotated toward each engagement pin 46 by the cylinder 17 with both units 2 and 3 in contact with each other, the engagement portion 15a of the cam 15 is rotated. , in a portion where the distance from the rotation axis is equal to the distance from the contact point of the engagement pin 46 and the cam 15 to the rotation axis when the contact surfaces of both units 2 and 3 are in contact with each other. It comes into contact with the engagement pin 46.

Furthermore, when the cam 15 is rotated, the engaging portion 1
5a presses the engagement pin 46 at a portion where the distance from the rotation axis is greater than the above distance, so both units 2 and 3 can be coupled and locked.

Moreover, since it has at least three coupling mechanisms, the weight of the tool acting on the coupling devices is
The weight is shared and supported by the at least three coupling mechanisms, and the weight supported by each coupling mechanism is reduced.

If the contact portions of the cam 15 and the engagement pin 46 are worn out due to an increase in the number of connections and separations between the first unit 2 and the second unit 3, the rotating shaft of the cam 15 will be damaged accordingly. The engaging portion 15a having a larger distance from the cam 15a comes to engage with the engaging pin 46, and the cam 15 and the engaging pin 46 are automatically connected to each other.
This means that the engagement function is reliably achieved regardless of the amount of wear.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

The figure shows an embodiment of an automatic tool changer according to the present invention. In FIG. 1, 1 is an automatic tool changer, 2 is a first unit attached to an operating means (not shown) such as a robot arm, and 3 is a second unit to which a spot welding gun 4 is attached. . A plurality of second units 3 each having various tools such as the spot welding gun 4 attached thereto are prepared and arranged on a shelf. During work, any one second unit 3
It is possible to select and combine and integrate the first unit 2 with the first unit 2 and have it perform a predetermined work using operating means such as a robot.

The upper first unit 2 has a main body part 2a and a convex part 2.
As shown in FIGS. 2 and 3, the main body portion 2a has a substantially Y-shaped shape formed by cutting out two substantially fan-shaped portions from a flat cylindrical member. . Interface modules 5 and 6 are removably attached to the cutout portions of the main body portion 2a, respectively, so that the entire body portion has a substantially single cylindrical shape. Also,
The uncut fan-shaped part 7 has an electrical conduit 8 on the side for sending control electrical signals to the tool attached to the second unit 3, and four air ports 9 for supplying and discharging control air to the tool. An electrical connector (not shown) connected to the electrical conduit 8 and a joint (not shown) communicating with the air port 9 are provided on the lower surface. A flange 10 is provided on the upper edge of the notch side of the main body 2a, and the interface modules 5 and 6 are bolted to this flange 10.

The convex portion 2b is formed in a star shape and protrudes from the lower surface of the main body portion 2a. These convex portions 2b are mutually
It consists of three parts 11 extending along three radii of 120° and joined to each other in the center.

The inside of the first unit 2 is cut out in a star shape similar to the convex part 2b with a depth reaching from the upper end surface to near the lower end of the convex part 2b, and each part 11 of the convex part 2b is cut out.
Three cylinder accommodating chambers 12 are formed along. This cylinder accommodation chamber 12 is a space that accommodates an air cylinder for driving a cam, which will be described later. The upper opening of the cylinder storage chamber 12 is closed by a lid 13 made of a circular plate attached to the upper surface of the main body 2a.

A rectangular hole is formed at the tip 11a of each portion 11 of the convex portion 2b, and a window 14 is provided.
A substantially fan-shaped cam 15 is provided within the cam 4. This cam 15 is supported in a plane parallel to the central axis of the first unit 2 by a support pin 16 that passes through the tip 11a of the portion 11 from the outside in the lateral direction (horizontal direction) and spans within the window 14. (in a vertical plane) and is rotatable between the exterior and interior of portion 11 through window 14 .

Portion 1 where the cam 15 engages with an engagement pin described below
5a is an arcuate edge portion. For this reason, the support pin 16 is provided at a position close to the corner 15b of the cam 15 on the opposite side from the engaging portion 15a. Further, since the distance between the engaging portion 15a of the cam 15 and the rotation shaft, that is, the support pin 16 is set to be minimum at the outer portion and gradually increase toward the inner side, the position of the support pin 16 is is set to be shifted downward from a straight line that bisects the angle between both ends of the arc-shaped engagement portion 15a.

The three cams 15 are each driven by driving air cylinders 17 provided along the radial direction in the three cylinder housing chambers 12 described above.
Each cylinder 17 has a mounting base 19 fixed to both inner surfaces of the portion 11 via a support member 18.
The first unit 2 is supported by the first unit 2 and can be rotated up and down along the central axis of the first unit 2. Air is supplied to and discharged from the driving air cylinder 17 through connecting pipes 22 and 23 from air ports 20 and 21 provided on the side surface of the main body 2a.

The cam 15 and the cylinder 17 each form a coupling mechanism together with an engaging pin to be described later, and these three coupling mechanisms constitute the coupling device of the automatic tool changer of the present invention.

The air cylinders 17 are each arranged such that the piston rod 24 is parallel to the cam 15. A U-shaped joint 25 is fixed to the tip of the piston rod 24 with its two legs facing the cam 15, and the cam 15 is held between the two legs of the joint 25. The cam 15 is rotatably connected to the cam 15. The connection between the joint 25 and the cam 15 is achieved by a connecting pin 26 provided through both. The connecting pin 26 passes through the cam 15 at a position close to the engaging portion 15a.

With the above configuration, when the driving air cylinder 17 is operated to move the piston rod 24 in and out,
The movement is transmitted to the cam 15 by the U-shaped joint 25 and the connecting pin 26, so that the cylinder 17 allows the cam 15 to be rotated around the support pin 16.

The interface module 5 is for supplying welding current to the welding gun 4, and has an electrical conduit 27 on the side surface, an electrical contact 28a on the bottom surface that supplies a large capacity current of about 100A, and a standard current of about 5A. Three electrical contacts 28b are provided for supplying the same. The other module 6 supplies cooling water to the welding gun 4, and is provided with a water port 29 on the side surface and two connection holes 30 on the bottom surface.

Note that 31 is a positioning pin provided on the lower surface of the main body portion 2a.

The second unit 3 has a substantially Y-shape similar to the first unit 2. Interface modules 32 and 33 are removably attached to the two substantially fan-shaped notches, respectively, so that the whole has a single cylindrical shape that is substantially the same as the first unit 2. These modules 32, 33 form a pair with modules 5, 6 attached to the first unit 2, and are arranged to overlap each other when both units 2, 3 are stacked.

The module 32 for supplying welding current has an electrical conduit 34 on its side and an electrical contact 35a for supplying a large current and three electrical contacts 35b for supplying a standard current on its top surface. Moreover, the module 33 for supplying cooling water is provided with two water ports 36 on the side surface and two joints 37 on the top surface. The electrical contacts 35a and 35b of the module 32 are located at positions corresponding to the electrical contacts 28a and 28b of the module 5 of the first unit 2, respectively, and are connected when both modules 32 and 5 are overlapped. The two joints 37 of the module 33 are also provided at positions corresponding to the two connection holes 30 of the module 6 of the first unit 2 so that they communicate when the modules 33 and 6 are overlapped. Note that both modules 32 and 33 are
Like the unit 2, it is bolted to a flange 38 provided at the lower part of the edge on the notch side.

The fan-shaped portion 39 of the second unit 3 has an electrical connector 40 and four couplings 41 that are respectively connected to electrical connectors and couplings (not shown) of the first unit 2 when both units 2 and 3 are overlapped. It is provided. This electrical connector 40 and joint 41
are connected to an electrical conduit 42 and four air ports 43 provided on the sides of the fan-shaped portion 39, respectively.

The center portion of the second unit 3 is cut out in a Y-shape to form a space 44 that is open upward and downward. The Y-shaped convex portion 2b of the first unit 2 fits into this space 44. A recess 45 recessed outward in the radial direction is formed at each of the three outer ends of the space 44, and an engaging pin extends from the outside of the second unit 3 in a parallel direction and spans the recess 45. 46
is provided. As shown in FIG. 5, this engaging pin 46 is provided at a position close to the upper end of the second unit 3, and is perpendicular to a plane containing the central axis of the second unit 3. When both units 2 and 3 are stacked, the inner wall surface 47 at each outer end of the space 44 has a first
The outer surface of the tip 11a of the convex portion 2b of the unit 2 contacts, and the outer end of the cam 15 fits into the recess 45.
The lower opening of the space 44 is closed by a lid 48 made of a circular plate attached to the lower end of the second unit 3. The spot welding gun 4 is attached via this lid 48.

Note that 49 is a positioning hole into which the positioning pin 31 of the first unit 2 is inserted;
is a joint connected to the air ports 20 and 21 of the first unit 2.

Next, the usage state of the automatic tool changer 1 configured as above will be explained.

Here, a case will be considered in which the second unit 3 to which the illustrated spot welding gun 4 is attached is selected from a plurality of second units 3 arranged on a rack with various tools attached thereto.

First, the first unit 2 attached to a robot arm or the like is moved above the second unit 3,
The two positioning pins 31 of the first unit 2 are
They are aligned with the two positioning holes 49 of the unit 3 and stopped.

Subsequently, when the first unit 2 is lowered and the positioning pin 31 is inserted into the positioning hole 49 of the second unit 3, and both units 2 and 3 are overlapped, the convex portion 2b of the first unit 2 becomes the second unit. 2 units 3
It fits into the space 44 of. At this time, each air cylinder 17 for driving the cam 15 has a piston rod 2.
Since air is supplied in the direction to retract the cam 4, most of the cam 15 is retracted inside the cylinder housing chamber 12, as shown in FIG. There is no problem.

When the lower end surface of the main body 2a of the first unit 2 and the upper end surface of the second unit 3 come into complete contact, an electrical connector (not shown) provided on the fan-shaped portion 7 of the first unit 2 and an air joint are automatically connected. , are connected to an electrical connector 40 and an air joint 41 provided on the fan-shaped portion 39 of the second unit 3, respectively. Also, the first
Electrical contacts 28 of modules 5 and 6 of unit 2
a, 28b and the air connection hole 30 are also connected to the electrical contacts 35 of the modules 32, 33 of the second unit 3.
a, 35b and the air joint 37, respectively.

In this way, it becomes possible to transmit the control electrical signals and air signals, welding current and cooling water sent from the robot to the first unit 2 to the spot welding gun 4 via the second unit 3. .

When both units 2 and 3 come into contact as described above, the operation valves (not shown) are operated to supply air to each air cylinder 17 in the opposite direction, and the piston rods 24 are synchronously protruded. let
Then, the three cams 15 connected to each piston rod 24 rotate outward about the support pin 16, and as shown in FIG. It contacts the engagement pin 46 of No. 3.

As mentioned above, the distance between the engaging portion 15a of the cam 15 and the support pin 16 is minimum at a position close to the engaging pin 46, and gradually increases as the distance from the engaging pin 46 increases. As the rotation angle increases, the force pressing the engagement pin 46 increases. In this way, the connection between both units 2 and 3 can be locked and maintained.

In this embodiment, the relative positions of the engagement pin 46 and the support pin 16 and the dimension relationship of the cam 15 are set appropriately when the two units 2 and 3 are coupled, and the cam 1
The position where the engaging portion 15a of the cam 15 presses the engaging pin 46 and stops is set inside the center position where the bisector of the central angle of the cam 15 intersects the engaging portion 15a. When a force acts in a direction to separate both units 2, 3, the moment due to the force acts mostly in a direction to rotate the cam 15 outward. Therefore, since the force acts in a direction that strengthens the locking force of both units 2 and 3, there is an advantage that it is very difficult to separate them even in such a case.

In addition, in consideration of the case where the air supply is stopped due to an accident such as a power outage, a spring is built into the cylinder 17 to ensure that the piston rod 24 remains protruding even if the air runs out during connection. It is preferable to configure it so that

When separating both connected units 2 and 3,
Air may be supplied to the cylinder 17 in the opposite direction to the above. In this way, the cam 15 rotates in the opposite direction and separates from the engagement pin 46, so that it can be easily separated.

In the above embodiment, three coupling mechanisms constituted by the cam 15, the cylinder 17, and the engagement pin 46 are provided at equal intervals around the central axis of each unit 2, 3, so that the weight of the tool can be reduced. This has the effect that the load is borne equally by each coupling mechanism. but,
Of course, this number may be four or more, and in this case as well, it is preferable to arrange the units 2, 3 at equal intervals around the central axis.

Further, in the above embodiment, the cam 15 is formed from a substantially fan-shaped plate, but the cam 15 is not limited to this.
It can be implemented in various shapes such as a disk shape and a cylindrical shape. Furthermore, the engaging portion 15a is not limited to a convex shape. The point is that the engaging portion of the cam includes a portion whose distance from the rotation axis is equal to the distance between the engagement pin and the rotation axis of the cam at the time of coupling, and a portion that is larger than the distance. It is sufficient if the distance changes gradually.

〔Effect of the invention〕

This invention has the configuration described above, and in each coupling mechanism, the cam 15 is connected to the engaging portion 1.
Since the coupling force between the two units 2 and 3 is generated by the force of pressing the engagement pin 46 through the lever 5a, this mechanism is more effective than the conventional device in which the pin is directly pressed and locked using the moment generated by the lever. The force that connects and locks both units 2 and 3 is extremely large, and the weight of the tool is shared and supported by at least three coupling mechanisms, so a tool weighing several hundred kilograms can be mounted. Even when the unit is operated, there is no fear that the attached tool will fall or vibrate, and furthermore, it has the effect of being highly rigid even against external forces in a direction perpendicular to the central axes of both units 2 and 3.

Furthermore, since the force acting on each coupling mechanism is reduced, the coupling device is less likely to be damaged and has greater durability.

When the three coupling mechanisms are arranged at equal intervals around the central axes of both units 2 and 3, the coupling force can be increased with a small number of coupling mechanisms, and the weight of the tool can be reduced between both units 2 and 3. This results in an effect of reducing costs and equalizing the burden on each coupling mechanism.

Furthermore, when a force is applied in the direction of separating the units 2 and 3, the force acts in a direction that further deepens the engagement between the cam 15 and the engagement pin 46. Therefore, the advantage is that the more force is applied in the direction of separating the units 2, 3, the stronger the engagement becomes. In addition, since the cam 15 and the engagement pin 46 reliably perform their engagement function regardless of the amount of wear, no rattling occurs when the first unit 2 and the second unit 3 are connected. Positioning accuracy is excellent.

[Brief explanation of the drawing]

The figure shows an embodiment of an automatic tool changer according to the present invention, and FIG. 1 shows a first unit and a second unit.
FIG. 3 is a perspective view showing the unit in a separated state. FIG. 2 is a plan view of the first unit used in the same device, with the lid partially cut away. FIG. 3 is a partial cross-sectional explanatory diagram taken along line A-A in FIG. 2. FIG. 4 is a plan view showing the second unit used in the same device. FIG. 5 is a partial cross-sectional explanatory diagram taken along line BB in FIG. 4.
FIG. 6 is a partially sectional explanatory view showing a state immediately before the convex portion of the first unit is fitted into the space of the second unit and both units are coupled by the coupling device.
FIG. 7 is a partially sectional explanatory view showing a state in which both units are coupled and locked by the coupling device.
FIG. 8 is a partially sectional explanatory diagram showing an example of a conventional automatic tool changer. DESCRIPTION OF SYMBOLS 1... Automatic tool changer, 2... First unit, 2a... Main body, 2b... Convex part, 3... Second
Unit, 4... Spot welding gun, 5, 6...
Interface module, 7... sector-shaped part, 11... convex part, 11a... tip part, 1
2... Cylinder storage chamber, 14... Window, 15... Cam, 15a... Engaging portion, 15b... Corner, 16...
...Support pin, 17...Air cylinder, 18...Support member, 19...Mounting base, 20, 21...Air port, 22, 23...Connecting pipe, 24...Piston rod, 25...Joint, 26 ... Connection pin, 31 ... Positioning pin, 32, 33 ... Interface module, 39 ... Sector-shaped portion, 44 ... Space, 45 ... Recess, 46 ... Engagement pin, 47 ... Tip part inner wall surface, 49... positioning hole.

Claims (1)

[Scope of Claims] 1. A first unit 2 connected to operating means of a robot, and at least one second unit 3 to which various tools can be attached. in the automatic tool changer configured to be separably connected to the first unit 2; a cam 15 that rotates to the other unit; and an engagement pin 46 provided on the other unit that allows the cam 15 to engage with the units 2 and 3 in contact with each other.
and a cylinder 17 for driving the cam 15.
The cam 15 includes an engaging portion 15 formed in a curved surface such that the distance from the rotation axis gradually changes.
a, and its engaging portion 15a is at a distance from the rotation axis to the point of contact between the engaging pin 46 and the cam 15 when the contact surfaces of both units 2 and 3 are in contact with each other. It includes a portion equal to the distance from to the rotation axis and a portion larger than the distance, and by rotating the cam 15 and bringing the engaging portion 15a into contact with and pressing the engaging pin 46. , an automatic tool changer characterized in that both units 2 and 3 are combined. 2. The cylinder 17 and the cam 15 are arranged in three cylinder housing chambers 12 arranged at equal intervals around the central axis of the one unit, and the engagement pin 46 is located at the center of the other unit. 2. The automatic tool changer according to claim 1, wherein three automatic tool changers are provided at equal intervals around the axis. 3. The automatic tool changer according to claim 1 or 2, wherein the cam 15 is made of a substantially fan-shaped plate, and the engaging portion 15a thereof is provided in an arc-shaped portion. 4. The position of the rotation axis of the cam 15 is such that at least a portion of the force in the direction of separating the two units 2 and 3 that are in contact increases the pressing force of the engagement pin 46 by the cam 15. Claim 3 characterized in that the position is set so as to act on the
Automatic tool changer described in .