JPH075992Y2 - Pressurizing robot - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure robot that moves a pressure cylinder that pressurizes a member to be pressed against a position-fixed member by a plurality of operating shafts. The present invention relates to a compact pressure robot in which an actuating shaft is not rotated by force.

2. Description of the Related Art (a) A pressurizing cylinder that is disposed at the tip end and pressurizes a member to be pressed against a position-fixed member, and (b) is connected in series and is relatively rotated and at any relative rotational position. The pressure cylinder is moved to a predetermined position such as a pressure position by being positioned by, while a rotation force is applied around the rotation center line of the relative rotation by the pressure reaction force of the pressure cylinder. A pressure robot having a plurality of operating axes is used, for example, in a spot welding robot that pressurizes a member to be welded to perform spot welding. In such a pressurizing robot, it is usual that the plurality of operating shafts are relatively rotated by an electric motor connected through a speed reducer.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, when the operating shaft is rotated by using the electric motor as described above, the electric motor projects laterally from the rotation plane of the operating shaft, so that the robot should be made compact. However, there is a problem in that an electric motor with a large torque must be used in order to prevent the actuating shaft from rotating due to the pressure reaction force.

Incidentally, Japanese Utility Model Laid-Open No. 61-9288 describes a robot which rotates an operating shaft by a cylinder.
If the operating shaft is rotated by using the brake cylinder with the position sensor described in Japanese Patent No. 2481, it is possible to position at any position while detecting the relative rotational position of the operating shaft. The protrusion disappears. However, in such a brake cylinder with a position sensor, the eccentric cam is rotated by the piston arranged in the direction perpendicular to the output rod to brake, and the rotary encoder is rotated by the guide rod provided parallel to the output rod. Since the position is detected by means of the robot, the size in the direction perpendicular to the output rod is large, and if it is used as a drive means for relatively rotating the operating shaft, the robot will rather be upsized. Not a thing. Also, since the eccentric cam is rotated to control, a high braking force is not always obtained only by applying a braking force to a part around the shaft center of the output rod. It is not always sufficient to prevent the rotation of the actuating shaft due to, and the output rod may be deformed when a large braking force is applied.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a compact pressurizing robot capable of favorably preventing the rotation of the operating shaft due to the pressurizing reaction force of the pressurizing cylinder. To do.

Means for Solving the Problems In order to achieve the above object, the present invention provides (a) a pressurizing cylinder that is disposed at a tip end and pressurizes a member to be pressed against a position-fixed member, and (b) serially. While being moved relative to the pressure cylinder and positioned at an arbitrary relative rotation position, the pressure cylinder is moved to a predetermined position,
In a pressurizing robot having a plurality of actuating shafts on which a rotational force is acted around the rotation center line of the relative rotation by the pressurizing reaction force of the pressurizing cylinder, (c) the output rod and the cylinder body are It is mounted so as to be capable of relative rotation about a center line parallel to the rotation center line across a plurality of operating shafts, and its operating shaft is relatively rotated by driving the output rod to project and retract. (C-1) A brake shoe concentrically arranged on the output rod so as not to move relative to the axial direction of the output rod, and a relative axial movement of the output rod concentric with the output rod. A piston that is arranged in the cylinder body so that it is possible, and a disc spring whose inner peripheral portion is arranged between the piston and the brake shoe and whose diameter can be reduced. A brake device that compresses the disc spring in the axial direction to reduce the diameter of the inner peripheral portion thereof, thereby crimping the brake shoe to the output rod and stopping the output rod from entering and exiting at an arbitrary position; 2) A large number of magnetic bodies embedded in the axial direction of the output rod at a predetermined constant pitch, and concentrically with the output rod, the magnetic rods are arranged in the cylinder body such that the output rod cannot move axially relative to each other. A drive means for relatively rotating the operating shaft of a brake cylinder with a position sensor having a position sensor having a sensor head that detects the amount of protrusion of the output rod based on the magnetic body by electromagnetic induction. It is characterized by being provided as.

In the pressurizing robot as described above, the output rod of the brake cylinder with the position sensor is ejected and pulled in to relatively rotate the operating shaft, while the position sensor detects the amount of protrusion of the output rod. Then, the brake device stops the movement of the output rod with respect to the cylinder body at a position where the output rod is protruded by a predetermined protrusion amount, whereby the operating shaft is positioned at the predetermined relative rotation position. As a result, the pressurizing cylinder is moved to a predetermined position such as the pressurizing position, and the pressurizing cylinder is operated at the pressurizing position to press the member to be pressed against the position-fixed member.

As described above, in the pressurizing robot of the present invention, since the brake cylinder with the position sensor is used as the driving means for the actuating shaft, the driving means does not protrude laterally from the rotating plane of the actuating shaft like an electric motor. Therefore, the pressurizing robot can be made compact. Further, in the above brake device, the disc spring is axially compressed by the piston arranged concentrically with the output rod, so that the brake shoe is pressed against the output rod to stop the output rod from entering and exiting at an arbitrary position. The position sensor detects the amount of protrusion of the output rod in which the magnetic material is embedded by the sensor head which is arranged concentrically with the output rod, and both are arranged concentrically with the output rod. The position sensor-equipped brake cylinder itself is small and compact, and has the advantage that it can be compactly arranged on the operating shaft of the pressurizing robot.

On the other hand, when the pressurizing cylinder presses the member to be fixed to the position-fixed member, the rotating force acts on the operating shaft by the pressurizing reaction force, but the position where the output rod is blocked by the brake device. The sensor-equipped brake cylinder serves as a tension rod to prevent the actuation shaft from rotating due to the pressure reaction force. In particular, in the above brake device, since the brake shoe arranged concentrically with the output rod is pressed against the output rod by the disc spring, a high braking force can be obtained as compared with the case of braking with the eccentric cam. As a result, the rotation of the operating shaft due to the pressurizing reaction force of the pressurizing cylinder can be satisfactorily prevented, and the output rod is not deformed even if a large braking force is applied to the brake shoe.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

1 and 2 are a front view and a right side view, respectively, of a spot welding robot 10 as a pressurizing robot according to an embodiment of the present invention. The robot 10 is a vertical multi-joint type 5-axis robot, and includes a turning shaft 12, a front-back shaft 14, a vertical shaft 16, an arm turning shaft 18, and a wrist bending shaft which are connected in series.
It is equipped with five working shafts 20 (hereinafter, working shafts 12, 14, 16, 18, 20 unless otherwise specified). The swivel shaft 12 is disposed on the base 22 so as to be rotatable around a substantially vertical center line l ₁ , and the front-rear shaft 14 has a substantially horizontal center line at the tip of the swivel shaft 12.
It is arranged so that it can rotate around l ₂ , and the vertical shaft 16 is its front and rear shafts.
14 is rotatably arranged around a center line l ₃ parallel to the center line l _2, and the arm swing shaft 18 is perpendicular to the center line l _{3 while} protruding from the end part of the vertical shaft 16. It is arranged so that it can be rotated around a center line l ₄ , and the wrist bending axis 20 is its arm turning axis.
It is arranged at the tip of 18 so as to be rotatable around a center line l ₅ orthogonal to the center line l ₄ .

The turning shaft 12, the arm turning shaft 18, and the wrist bending shaft 20 are connected by an electric motor 24, 26, 28 via a reduction gear (not shown),
In addition, the front and rear shafts 14 and the vertical shafts 16 are provided with brake cylinders with position sensors (hereinafter simply referred to as cylinders) 30 and 32, respectively.
Each of them is rotated within a predetermined operating range. The cylinders 30 and 32 have substantially the same configuration, and the brake devices 38 and 40 are integrally assembled to the tip end portions of the cylinder bodies 34 and 36 so that the output rods 42 and 44 can be stopped in an inaccessible position at arbitrary positions. In addition to the above, a position sensor 46 as shown in FIG. 3 is incorporated in the cylinder bodies 34 and 36, for example. The pivot shaft 12, the front-rear shaft 14, and the vertical shaft 16 correspond to a plurality of actuating shafts described in the scope of claims for utility model registration.

The position sensor 46 has a fixed pitch P on the output rod 42 (44).
A large number of magnetic bodies 48 are embedded in the output rod
A sensor head 54 in which a plurality of primary coils 50 and a plurality of secondary coils 52 are provided around the 42 (44) at predetermined intervals, respectively.
By placing an exciting current of a sin ω t, a cos ω t between the terminals A and B of the primary coil and between C and D, respectively, between the terminals E and F of the secondary coil 52, With respect to the movement amount X of the output rod 42 (44) due to electromagnetic induction, K sin (ω
The signal represented by t-2πX / P) is taken out. Therefore, this output signal K sin (ωt-2πX / P) and terminals A and B
The movement amount X is obtained from the phase difference from the exciting current a sin ω t that is applied between the output rod 42 and the output rod 42 based on the movement amount X.
The protrusion amount of (44) is detected. The above a, b and K are proportional constants.

Further, the brake device 38 (40) is provided with a front side pressure chamber 58a, 58b by a switching valve 56 as shown in FIG. 4, for example.
Pressure air is supplied to the pistons 62a, 62
b is retracted against the urging force of the spring 64, the compressed state of the disc springs 66a, 66b is released, and the inner diameter of the disc springs 66a, 66b is expanded, so that the brake shoe 68 for the output rod 42 (44).
Release the crimped state of a and 68b, and then output rod 42 (44)
While allowing free movement of the piston 62a, the switching valve 56 supplies pressure air from the air source 60 to the rear pressure chamber 70.
62b is moved forward, the disc springs 66a, 66b are axially compressed, and the inner diameter thereof is reduced, so that the brake shoes 68a, 68b are crimped to the output rod 42 (44) and the output rod 42 (44). Configured to prevent the free movement of.

The cylinder body 34 of the one cylinder 30 includes a pin 76 parallel to the rotation center line l ₂ between the pair of side plates 72 and 74 of the swivel shaft 12.
The output rod 42 is mounted so as to be capable of relative rotation about the pin 80, and the output rod 42 is relatively rotated about a pin 80 parallel to the rotation center line l _{2 on} a protrusion 78 protruding from the front-rear shaft 14 at its tip. It is possible to install. Therefore, when the output rod 42 of the cylinder 30 is driven to protrude and retract, the front-rear shaft 14 rotates with respect to the swivel shaft 12 along the rotation center line l ₂
On the other hand, the position sensor 46 detects the amount of protrusion of the output rod 42 while being rotated relative to the surroundings. When the cylinder is stopped, the cylinder 30 serves as a tension rod and a triangular shape having the pins 76, 80 and the rotation center line l ₂ at the apex is positioned undeformable, and the front-rear shaft 14 is rotated by a predetermined relative rotation. Positioned in the moving position. The protrusion stroke of the output rod 42 is set to a dimension that allows the front-rear shaft 14 to relatively rotate within a predetermined operation range.

Further, the cylinder body 36 of the other cylinder 32 is mounted between the pair of side plates 72, 74 of the swivel shaft 12 so as to be relatively rotatable about a pin 82 parallel to the rotation center lines l ₂ , l _3. Cage,
The output rod 44 has a pin 8 parallel to the rotation center lines l ₂ and l ₃ on the projection 84 protruding from the vertical shaft 16 at the tip thereof.
It is attached so that it can rotate about 6 parts. Therefore, in the state where the relative rotational position of the front-rear shaft 14 with respect to the turning shaft 12 is positioned by the cylinder 30,
When the output rod 44 of the cylinder 32 is driven to protrude and retract, the vertical shaft 16 is relatively rotated with respect to the front-rear shaft 14 around the rotation center line l ₃ , while the position sensor 46 causes the output rod 44 of the output rod 44 to rotate. When the protrusion amount is detected and the output device 44 is protruded by a predetermined protrusion amount, and the brake device 40 stops the movement in and out of the cylinder body 36, the cylinder 32 serves as a tension rod and the pin 82. , 86 and the triangular shape having the rotation center line l ₃ as its apex are positioned so that they cannot be deformed, and the vertical shaft 16 is positioned at a predetermined relative rotation position. The protrusion stroke of the output rod 44 is set to a dimension that allows the vertical shaft 16 to relatively rotate within a predetermined operating range. For ease of understanding, the state in which the relative rotational position of the front-rear shaft 14 with respect to the turning shaft 12 is positioned by the cylinder 30 has been described, but the cylinders 30 and 32 are normally operated simultaneously. Further, the cylinder body 36 of the cylinder 32 may be attached to the front-rear shaft 14 without any problem.

On the other hand, the wrist bending shaft 20 has a stud gun 88 for welding.
Are attached in a posture orthogonal to the rotation center line l ₅ . The stud gun 88 is a reciprocating type pressure cylinder 90 having an upper electrode 94 attached to the tip of an output rod 92, and is fixed to the wrist bending shaft 20 at the rear end of the pressure cylinder 90. , The upper electrode 94 is the energizing cable 9
It is connected to the + terminal of a welding transformer (not shown) through 6, current-carrying bars 98, 100 and current-carrying cable 102. The current-carrying bars 98, 100 are connected by a connecting member 104 so as to be relatively rotatable around a center line parallel to the rotation center lines l ₂ , l _3, and at both ends thereof, the rotation center lines l ₂ , l _{3 are also the same.} And the vertical shaft 16 and
It is attached to the swivel shaft 12.

A pair of works 110, 112 to be welded are positioned and placed on a positioning jig 114, and a lower electrode 116 is fixedly provided at the welding position of the works 110, 112. This lower electrode 116 is a power cable 1
It is connected via 18 to the minus terminal of the welding transformer.

Then, in the spot welding robot 10 configured as described above, first, the respective operating axes, that is, the swivel axis 12, the front-rear axis 14, the vertical axis 16, the arm swivel axis 18, and the wrist bending axis 20 are the electric motors 2.
By rotating the stud gun 88 by a predetermined rotation amount by the 4, 26, 28 and the cylinders 30, 32, respectively, the work 110, 11 can be moved right above the predetermined welding position of the stud gun 88.
Position it so that it is almost perpendicular to 2. In this state, the turning positions of the turning shaft 12, the arm turning shaft 18, and the wrist bending shaft 20 are positioned by the braking action of the electric motors 24, 26, and 28, and the turning positions of the front-rear shaft 14 and the vertical shaft 16 are respectively set. The cylinders 30 and 32 are positioned by the brake devices 38 and 40.

Next, the upper cylinder 94 is projected by the pressurizing cylinder 90 of the stud gun 88, and the pair of works 110 and 112 is clamped between the lower cylinder 116 and the work. The works 110 and 112 correspond to members to be pressed, and the lower electrode 116 corresponds to a member for fixing the position. Then, when a welding current is output from the welding transformer in that state, the welding current is applied to the energizing cable 102,
Upper electrode 94 via current-carrying bars 100, 98 and current-carrying cable 96
Is supplied to the negative terminal of the welding transformer through the workpieces 110, 112, the lower electrode 116, and the energizing cable 118,
At this time, these works 110 and 112 are welded based on the heat generated by the electric resistance between the works 110 and 112.

The pressure applied by the pressurizing cylinder 90 is usually several hundred kgf, and 700 kg depending on the welding conditions such as the plate thickness and material of the workpieces 110 and 112.
In some cases, a pressure of about f may be required. Therefore, due to the pressure reaction force, a force is applied to the wrist bending shaft 20 in the direction opposite to the pressure direction, and a rotational force is applied to the front-rear shaft 14 and the vertical shaft 16. 14, Since the rotation position of the vertical shaft 16 is firmly positioned by the cylinders 30 and 32, the rotation of the front and rear shaft 14 and the vertical shaft 16 due to the pressure reaction force,
Further, welding defects due to escape and displacement of the pressure cylinder 90 are prevented.

Then, when the welding work is completed in this way, the supply of the welding current is stopped, the output rod 92 of the pressurizing cylinder 90 is drawn in, and the pressurization state of the works 110, 112 is released.
Thereafter, the electric motors 24, 26, 28 and the cylinders 30, 32 rotate the respective operating shafts 12, 14, 16, 18, 20 by a predetermined amount of rotation, whereby the stud gun 88
Is moved to another welding position, and the welding operation described above is repeated.

Here, in the spot welding robot 10 of the present embodiment, the front and rear shafts 14 and the vertical shafts 16 which are rotated around the rotation center lines l ₂ and l _{3 which} are parallel to each other are rotated by the cylinders 30 and 32, respectively. Therefore, all the driving means including the electric motors 24, 26, 28 for rotating the other operating shafts 12, 18, 20 can be located in a substantially common plane, and The dimensions of the vertical axis 14 and the vertical shaft 16 in the direction perpendicular to the plane of rotation are shortened, and the robot 10 is made compact. In the cylinders 30 and 32, the brake devices 38 and 40 and the position sensor 46 are arranged concentrically with the output rods 42 and 44, so that the cylinders 30 and 32 themselves are configured to be small and compact. There is an advantage that it can be compactly arranged between 12,14 and between 12,16.

In addition, the brake devices 38 and 40 stop the output rods 42 and 44 from moving in and out, so that the front and rear shafts 14 and the vertical shafts 16
Since the rotation position of the pressure cylinder 90 is positioned, the rotation of the front-rear shaft 14 and the vertical shaft 16 due to the pressure reaction force of the pressure cylinder 90 is favorably prevented. The brake devices 38, 40 are configured so that the brake shoes 68a, 68b arranged concentrically with the output rods 42, 44 are crimped to the output rods 42, 44 by the disc springs 66a, 66b. As compared with the case of performing the above, a higher braking force can be obtained, and the rotation of the front-rear shaft 14 and the vertical shaft 16 due to the pressurizing reaction force of the pressurizing cylinder 90 can be prevented more effectively, and the brake shoes 68a, 68b can be made larger. There is no fear that the output rods 42, 44 will be deformed even if a braking force is applied.

Particularly, in this embodiment, the cylinder bodies 34, 36 of the cylinders 30, 32 are
Is disposed between the pair of side plates 72, 74 of the swivel shaft 12, so that the reaction force under pressure can be well received and the robot 10 can be made more compact.

Next, another embodiment of the present invention will be described. In the following embodiments, parts that are substantially the same as those in the first embodiment will be designated by the same reference numerals and description thereof will be omitted.

The embodiment shown in the front view of FIG. 5 and the right side view of FIG. 6 is different from the first embodiment in that the front-rear shaft 14 is composed of two side plates 120 and 122, and between them. In cylinder 3
By arranging 0, the cylinder 30 is prevented from protruding to the right in FIG. 1 and the robot 10 is made more compact. The cylinder body 34 includes side plates 120, 122.
Is relatively rotatably mounted around a pin 124 parallel to the rotation center line l _2, and the output rod 42 is rotatably mounted on the swivel shaft 12 around a pin 126 also parallel to the rotation center line l _2. Has been. Incidentally, 128 and 130 are covers for the electric motors 26, 28 and the cylinder 32, respectively.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention can be implemented in other modes.

For example, in the above-described embodiment, the case where the present invention is applied to the robot 10 for spot welding has been described, but the present invention is also applied to other pressurizing robots such as a clamp device for pressurizing and clamping a work on a position fixing member. Can be applied similarly.
It can also be applied to other types of robots such as horizontal articulated robots.

Further, in each of the above-described embodiments, two cylinders 30 and 32 are used, but it is possible to provide one cylinder or three or more cylinders depending on the configuration of the robot.

Further, the brake device 38 (40) shown in FIG. 4 is merely an example, and if the movement of the output rod 42 (44) can be stopped at an arbitrary position, for example, one having only one piston It is also possible to employ a brake device having a configuration.

Further, in the above-mentioned embodiment, the current-carrying bars 98 and 100 are used to supply the welding current to the stud gun 88, but it goes without saying that the means for supplying the welding current can be changed appropriately.

Although not illustrated one by one, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a front view of a spot welding robot according to an embodiment of the present invention. FIG. 2 is a right side view of the robot shown in FIG. FIG. 3 is a diagram illustrating an example of a position sensor of a brake cylinder with a position sensor in the robot of FIG. FIG. 4 is a sectional view showing an example of a brake device for a brake cylinder with a position sensor in the robot shown in FIG. FIG. 5 is a partially cutaway front view of another embodiment of the present invention. FIG. 6 is a right side view of the embodiment shown in FIG. 10: Robot (pressurizing robot) 12,14,16: Actuating axis 30,32: Brake cylinder with position sensor 34,36: Cylinder body 38,40: Brake device 42,44: Output rod, 46: Position sensor, 48 : Magnetic material, 54: Sensor head, 62a, 62b: Piston, 66a, 66b: Disc spring, 68a,
68b: brake shoe, 90: pressure cylinder, 110, 112: workpiece (object to be pressure member), 116: lower electrode (stationary member) l _2, l _3: pivot axis

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takanori Nakamura 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Yoshitaka Sakamoto 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (56) References Japanese Unexamined Patent Publication No. 60-62481 (JP, A) Actual development No. 61-9288 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A pressure cylinder, which is disposed at a tip portion and pressurizes a member to be pressed against a position-fixed member, is connected in series to be relatively rotated, and is positioned at an arbitrary relative rotation position. Thereby moving the pressurizing cylinder to a predetermined position, and a plurality of actuating shafts on which rotational force is applied about the rotation center line of the relative rotation by the pressurizing reaction force of the pressurizing cylinder. In a pressure robot, an output rod and a cylinder body are mounted rotatably relative to each other around a center line parallel to the rotation center line, straddling the plurality of operating shafts, and the output rod is ejected and retracted. Thereby rotating the actuating shaft relative to each other, and concentrically with the output rod, the brake shoe disposed on the cylinder body so as to be relatively immovable in the axial direction of the output rod; A piston arranged in the cylinder body concentrically with the force rod so as to be relatively movable in the axial direction of the output rod;
An inner peripheral portion disposed between the piston and the brake shoe is provided with a disc spring whose diameter can be reduced, and the disc spring is axially compressed by the piston to reduce the inner peripheral portion. A brake device that presses the brake shoe onto the output rod to stop the output rod from entering and exiting at an arbitrary position, and a large number of magnetic bodies embedded in the axial direction of the output rod at a predetermined constant pitch. And a sensor head that is disposed concentrically with the output rod in the cylinder body such that the output rod cannot move relative to the axial direction, and that detects the amount of protrusion of the output rod based on the magnetic body by an electromagnetic induction action. A pressurizing robot comprising a position sensor equipped with a brake cylinder with a position sensor as a drive means for relatively rotating the operating shaft.