JPH0729267B2 - Automatic tool changer - Google Patents

Description

TECHNICAL FIELD The present invention relates to an automatic tool changer which is used in a robot hand or the like and is capable of automatically changing tools.

[Prior Art] An arm of an industrial robot is equipped with an automatic tool changer for changing a tool for machining. This automatic tool changer is capable of aligning and connecting a tool plate with a tool integrated with a fixed plate connected to an arm of a robot.

FIG. 5 is a schematic view showing a structure for attaching and detaching the fixed plate 50 and the tool plate 51 which have been conventionally adopted.

In the case of the same figure (a), a mounting hole 52 is opened in the fixed plate 50, and a shaft 53 fitted in the mounting hole 52 is formed in the tool plate 51.
Is an example in which is provided. The mounting hole 52 and the shaft 53 have an axis parallel to the attachment / detachment direction of the fixed plate 50 and the tool plate 51, and by providing a plurality of sets, the position of the tool plate 51 with respect to the fixed plate 50 can be determined. Further, FIG. 9A shows that the tool plate 51 is fixed to the fixed plate 50 after the mounting hole 52 and the shaft 53 are aligned and then fitted.
These plates 50 and 51 are integrated by a mechanism for restraining to the side, that is, a claw 50c.

Further, FIG. 2B shows an example in which the tool plate 51 is inserted into the shank receiver 50a of the fixed plate 50, and the tool 54 is aligned and mounted on the fixed plate 50 by the pair of mounting holes 52 and the shaft 53.

[Problems to be Solved by the Invention]

Thus, in order to attach / detach the tool plate or the tool itself to / from the fixed plate on the robot hand side, the fitting between the mounting hole 52 and the shaft 53 is used. It is necessary to align each of them.

However, if the alignment is insufficient, a large load is applied to the mounting hole 52 and the shaft 53 due to the gravity of the robot at the time of fitting, and the fixed plate 50, the tool plate 51, and the tool 54 themselves may be damaged. As described above, in the conventional structure, the quality of alignment before coupling with the tool side has been an important issue.

On the other hand, in the automatic tool changer, various tools are used by being replaced, so that the fastening function with the tool side and the positioning function for positioning the tool after fastening are important. Among these functions, the positioning function aims to accurately perform three-dimensional coupling of the axial direction on the fixed side and the plane coordinates having the origin on this axis.

Further, the fastening function aims to fix the tool accurately positioned on the fixed side by the positioning function so that the tool does not move or fall off. Since a considerably large load is applied to these mechanical elements during processing, the positioning element is generally made to have a strong structure so that most of the loads can be received, and the fastening mechanism is loaded only in a certain direction. To do.

For example, as shown in FIG. 6 (a), the surface 50b and the surface 53c receive a load in the axially compressing direction, and the torque around the axis is 2
A shaft 53 of the book is inserted into the hole 52 to receive it. Therefore, only the force in the opposite direction of compressing the surfaces 50b and 53c of the axial load acts on the claw 50c of the fastening element. By doing so, the fastening mechanism can be simplified and downsized.

However, in such a structure, although it is preferable to reduce the size and weight of the automatic exchange device as a whole, the miniaturization is limited because each functional element is composed of a separate component.

Further, for example, JP-A-61-117087 and JP-A-61-118.
Japanese Patent Publication No. 8096 describes a configuration capable of solving such a problem. The former allows the lock pin to move back and forth in the direction of the lock hole by the taper shape of the actuator driven by the cylinder provided on the fixed plate side, and the latter has a structure in which the lock pin and the lock hole are tapered. .

With such a configuration, the fixed plate side and the tool plate side can be quickly coupled by absorbing the mutual positional deviation, and the overall size of the device can be reduced.

However, for example, in the case of an actuator with only a tapered shape as described in the former case, if the pressure of the hydraulic oil is released to the cylinder, the actuator will move and the lock pin will move out of the lock hole. It may move. For this reason, during machining work using a tool, there is a risk that the tool plate will sway and positioning will not be possible, or the tool plate may fall off the fixed plate.

The problem to be solved in the present invention is to enable the fastening of the tool side and the fixed side with high accuracy, and to hold and operate the tool plate even when the pressure of the hydraulic oil of the cylinder provided in the fixed plate is released. is there.

[Means for Solving the Problems]

The present invention includes a fixed plate connected to an arm of a robot hand and the like, and a tool plate on which a tool is mounted, and the fixed plate includes a lock pin that advances and retreats in a direction orthogonal to the attachment / detachment direction to the tool plate, A cylinder for driving the actuator in which the lock pin abuts the peripheral surface in a direction orthogonal to the axis of the lock pin, and the tool plate is provided with a lock hole into which the lock pin is fitted. An automatic tool changer in which the copying lock pin is urged to be movable in the axial direction, and the lock pin and the lock hole are tapered fitting type, wherein the actuator has a taper portion whose front end side is tapered. , A straight part having the same outer diameter as the upper end of the tapered part and parallel to the axis of the actuator, and a continuous part from the upper end of the straight part. Each of the lock pins is capable of following a taper portion and a linear portion of a portion of the lock pin that abuts the peripheral surface of the actuator. With an outer shape, the outer diameter of the linear portion of the actuator is set such that when the lock pin hits the linear portion, the tip of the lock pin can be inserted into the lock hole by a certain incomplete depth. Characterize.

[Operation] By supplying and discharging the working fluid to and from the cylinder, the actuator advances and retracts in the axial direction, and at this time, the lock pin that abuts the peripheral surface of the actuator moves in the axial direction of the actuator while following the taper portion and the linear portion of the actuator. That is, as the actuator advances, the lock pin is pushed outward by the tapered portion and fits into the lock hole of the tool plate.

When the pressure of the working fluid in the cylinder is released, the actuator moves to the cylinder side because the actuator receives the acting force from the lock pin on the retracted side by the taper portion. On the other hand, the actuator is provided with a straight line portion connected to the taper portion at the tip thereof, and when the lock pin hits the straight line portion, the lock pin enters the lock hole to an incomplete depth. Therefore, when the lock pin hits the straight line portion, the acting force from the lock pin is present only in the central direction of the actuator, the component force for retracting the actuator is not generated, and the lock pin remains restrained in the lock hole. Therefore, the movement of the actuator is prevented unless the working fluid is supplied or discharged, and the lock pin can be prevented from coming off from the lock hole.

〔Example〕

FIG. 1 is a longitudinal sectional view of an essential part showing an outline of a fastening structure of an automatic tool changing device of the present invention, and FIG. 2 is a transverse sectional view.

In the figure, a fixed plate 1 is connected to the tip of an arm A of a robot hand, and a tool plate 2 is detachably attached to the fixed plate 1.

As shown in FIG. 2, the fixed plate 1 has a circular cross section and is provided with three lock pins 3 which can be moved forward and backward from the center in the radial direction. The tips of these lock pins 3 are formed in a tapered shape and are urged toward the center by elastic means, so that when the tool plate 2 is not attached, the tips do not project as shown in FIG. 2 (a). Is set to.
Further, a cylinder 4 for pushing out the lock pins 3 is formed inside the fixed plate 1, and the taper portion of the tip end of the actuator 5 thereof fits into the base end portions of the three lock pins 3. By the operation of this actuator 5,
The lock pin 3 is pushed outward as shown in FIGS. 1 (b) and 2 (b).

On the other hand, the tool plate 2 has a necessary tool 2a attached to one surface thereof, and has a concave sectional shape into which the fixed plate 1 is fitted. A lock hole 6 into which the lock pin 3 is fitted is provided on the peripheral wall 2b. The lock hole 6 is a taper hole matched with the taper portion of the lock pin 3, and the tool plate 2 is connected and held to the fixed plate 1 by the lock pin 3 and the lock hole 6 which are tapered.

After the fixed plate 1 is fitted into the tool plate 2, when the cylinder 4 is operated and the actuator 5 is lowered in the figure, this pushes the base end portion of the lock pin 3 and spreads it, and the lock pin 3 is extended. Insert the tip of the lock pin 3 into the lock hole 6 as shown in (b). At this time, since the lock pin 3 and the lock hole 6 are taper-fitted to each other, even if their axial centers are deviated, the lock pin 3 is positioned slightly above the lock hole 6, and the tip thereof is the opening of the lock hole 6. If included, the lock pin 3 advances while lifting the tool plate 2 as the fitting progresses, and the lock hole 6 correspondingly fits along the lock pin 3 in correspondence with this. Therefore, even if the alignment is not sufficient, the lock pin 3 and the lock hole 6
Joining with is easy. Also, the tool plate 2
The fixed plate 1 and the fixed plate 1 are attracted to each other by the taper fitting of the lock pin 3 and the lock hole 6, and the positioning and the connection can be surely performed at the same time without a mechanism for restraining in the attaching and detaching direction.

FIG. 3 is a vertical cross-sectional view showing a specific structure of the essential part of the present invention.

An actuating hole 7 is formed in the fixed plate 1 coaxially with the cylinder 4, and the actuator 5 moves in this. Further, a holding hole 8 for the lock pin 3 is provided so as to extend in the radial direction around the actuation hole 7. This holding hole 8 is a guide part at the tip.
8a and a spring accommodating portion 8b having a larger diameter than that are arranged coaxially.

The lock pin 3 has a flange 3a that slides on the inner peripheral wall of the spring accommodating portion 8b at the base end side, and the tip end is a tapered taper portion 3b. The rear surface of the flange 3a is formed in a pointed shape of the conical surface 3c as shown in the drawing, so that the forward / backward movement orthogonal to the movement of the actuator 5 is smooth. A spring 8c whose one end abuts on the flange 3a is arranged in the spring housing portion 8b, and the lock pin 3 is biased toward the center side. By the biasing force of this spring 8c,
When the actuator 5 is at the position indicated by the alternate long and short dash line in FIG. 3, the lock pin 3 is retracted to the position indicated by the alternate long and short dash line in the figure, and its tip is housed in the holding hole.

The cylinder 4 is provided inside the fixed plate 1 and has ports 4a and 4b for supplying and discharging a working fluid. A piston 5a having the actuator 5 integrated therein is provided inside, and the actuator 5 is driven up and down in the drawing by supplying and discharging the working fluid.

On the peripheral surface of the actuator 5, a taper portion 5b, a straight portion 5c, and an additional tightening taper portion 5d are formed from the lower end. The inclination of the taper portion 5b and the additional tightening taper portion 5d is set to be substantially equal to the inclination of the conical surface on the back surface of the flange 3a.

Further, the lock hole 6 provided in the tool plate 2 is provided so as to match the position of the lock pin 3, and the fixed plate 1 and the tool plate 2 are positioned by utilizing the restraint by these. The lock hole 6 is formed as a taper hole that matches the inclination of the taper portion 3b of the lock pin 3.
Together with taper fitting.

In the above configuration, the fixed plate 1 and the tool plate 2
The connection with and is performed as follows. First, after roughly aligning the positions of the three lock pins 3 and the lock holes 6 of the tool plate 2, the fixing plate 1 is inserted into the tool plate 2 as shown in FIG. After that, the working fluid is sent from the port 4a using the external working oil supply system, and the actuator 5 is lowered. By this movement of the actuator 5, the taper portion 5b, the straight portion 5c, and the retightening taper portion 5d
The rear surface of the flange 3a hits in this order, and the lock pin 3 is pushed outward. The taper portion 3b at the tip of the lock pin 3 projects from the peripheral surface of the fixed plate 1 and fits into the lock hole 6 in the inner peripheral wall of the tool plate 2.

Here, as shown in FIGS. 4A and 4B, the axial center of the lock pin 3 in the initial stage of fitting with respect to the center of the lock hole 6 is
Even if they are laterally shifted from e and vertically shifted from E, the lock pin 3 can be finally fitted into the lock hole 6 exactly. That is, since the lock pin 3 and the lock hole 6 are taper-fitted, if the tip of the lock pin 3 is included in the opening portion of the lock hole 6 and the lock pin 6 is at a position where the lock pin 3 can be lifted, a tapered surface is formed. The lock hole 6 gradually fits into the lock pin 3 while being aligned. Therefore, even if the positions of the lock pin 3 and the lock hole 6 are not accurately aligned, they can be fitted smoothly and satisfactorily.

When the lock pin 3 is fitted into the lock hole 6, the positioning of the fixed plate 1 and the tool plate 2 is completed, and at the same time, these plates 1 and 2 are restrained to each other. That is, since the lock pin 3 and the lock hole 6 are tapered,
As the degree of fitting becomes stronger, the acting force that attracts the fixed plate 1 and the tool plate 2 acts in the connecting direction orthogonal to the taper axis. Therefore, even if the fitting shaft is not provided in the attachment / detachment direction of the fixed plate 1 and the tool plate 2,
These members are firmly connected by taper fitting,
Machining using 2a is also performed well.

Further, even if the working fluid supply system to the cylinder 4 fails and the pressure cannot be held by the working fluid, it can be kept fitted in the lock pin 3 and the lock hole 6.

That is, in FIG. 3, when the working pressure of the working fluid supplied from the port 4a decreases, the piston 5a moves upward when an external force acts. On the other hand, as shown in the figure, the conical surface 3c of the flange 3a is in contact with the retightening taper portion 5d, so that a component force for moving the actuator 5 upward acts. As a result, the actuator 5 begins to move upward, but when the apex 3d of the conical surface 3c of the flange 3a separates from the tightening taper portion 5d and hits the straight line portion 5c, the lock pin 3 moves only in the direction orthogonal to the axis line of the actuator 5. Give a pressing force to. Therefore, there is no component force to move the actuator 5 upwards, and the actuator 5 moves its linear portion 5c.
It is held at the position where the apex 3d of the conical surface 3c is abutted against.

Therefore, even if the working fluid supply system or the cylinder 4 itself breaks down, if the tapered portion 3b at the tip stops in the lock hole 6 when the apex 3d moves to the straight portion 5c, The fixed plate 1 and the tool plate 2 remain locked. Once locked in this way, the tool plate 2 is not separated from the fixed plate 1 unless the cylinder 4 is operated and released, and the tool plate 2 drops even if the working fluid supply system or the like fails during processing. You can work safely without accidents.

It should be noted that, instead of the tip of the lock pin 3 being tapered as shown in FIGS. 1 to 4, the lock pin 3 is provided as shown in FIG.
The tip of may have a spherical shape 13. Even in the case of the spherical shape 13, it is of course possible to make the outer diameter smaller than the diameter of the open end of the lock hole 6 so that the lock hole 6 can be sufficiently fitted into the lock hole 6.

If the tip of the lock pin is spherical,
As shown in the figure, the taper axis of the lock hole 6 is the lock pin 3
Even if it is formed with a slight inclination with respect to the shaft center due to a manufacturing error, a part of the spherical surface is always in line contact 13a with the tapered surface, so that the positioning function has excellent stability.

〔The invention's effect〕

According to the present invention, since the actuator is provided with the linear portion that moves the lock pin only to the incomplete depth on the tip side of the reinforced tightening taper portion that completely fits the lock pin into the lock hole, the lock pin is fixed to the fixing plate. When the cylinder is connected to the lock hole, even if pressure loss of the working fluid of the cylinder occurs, the lock is not released unless the actuator is driven. Therefore, even if the working fluid supply system fails during the working operation, the tool plate does not separate from the fixed plate, and the safe operation can be achieved.

[Brief description of drawings]

1 (a) is a schematic cross-sectional view showing a fixed plate and a tool plate before being combined, FIG. 1 (b) is a schematic cross-sectional view showing after combining, and FIG. 2 (a) is a schematic cross-sectional view before being combined. 2 (b) is a schematic cross-sectional view after coupling, FIG. 3 is a cross-sectional view of a main part showing a drive structure of a lock pin by an actuator, FIG.
The figure is a view for explaining the fitting state of the lock pin by the taper fitting type, FIG. 5 is a schematic sectional view when the lock pin having a spherical tip is locked in the tapered lock hole, and FIG. FIG. 6 is a schematic diagram of an example. 1: Fixed plate, 2: Tool plate 2a: Tool, 2b: Peripheral wall 3: Lock pin, 3a: Flange 3b: Tapered part, 3c: Conical surface 3d: Vertex 4: Cylinder, 4a, 4b: Port 5: Actuator, 5a : Piston 5b: Tapered part, 5c: Straight part 5d: Re-tightening taper part 6: Lock hole, 7: Actuating hole 8: Holding hole, 8a: Guide part 8b: Spring housing part 8c: Spring 13: Spherical shape

Claims (1)

[Claims] 1. A fixed plate connected to an arm or the like of a robot hand, and a tool plate on which a tool is mounted, wherein the fixed plate has a lock pin that moves back and forth in a direction orthogonal to a direction in which the tool plate is attached and detached. A cylinder for driving the actuator in which the lock pin abuts the peripheral surface in a direction orthogonal to the axis of the lock pin, the tool plate includes a lock hole into which the lock pin is fitted, and the outer shape of the actuator Is an automatic tool changer in which the lock pin is movably biased in the axial direction thereof and the lock pin and the lock hole are tapered fitting type, wherein the actuator has a taper with its tip side tapered. Section, a straight section having the same outer diameter as the upper end of the tapered section and parallel to the axis of the actuator, and the upper end of the straight section Each of the lock pins is capable of following the taper portion and the straight line portion of the portion of the lock pin that abuts the peripheral surface of the actuator. The outer diameter of the linear portion of the actuator is set so that the tip of the lock pin can be inserted into the lock hole by a certain incomplete depth when the lock pin hits the linear portion. Tool changer.