RU2762223C2 - Docking device - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to a docking device for installing and securing replaceable tools and grips located in the storage magazine at the final link of the manipulator of an industrial robot. The device contains the connecting surfaces of the connecting elements facing each other with the centering elements in the form of fingers and holes for them, mirrored on them, while the end link of the manipulator and the tool and grip housings are equipped with connecting platforms made of non-magnetic material, two holes are made on the docking surface of the platform of the end link of the manipulator, in which electromagnets with a housing anchor are coaxially installed, ferromagnetic housings of which in the form of cups are provided with covers made integral with the cores of coils, installed inside the housings and equipped with bypass collars on the flat ends of the mentioned cores. The bottoms of the cups facing towards the fingers have central holes equipped with guide chamfers, which are centering elements for two ferromagnetic fingers equipped with flanges with diameters equal to the outer diameter of the electromagnet housings mounted on another platform, which are the housing anchors of the mentioned electromagnets. In this case, one of the fingers is cylindrical, the other finger, made with a cross-section in the form of a rhombus, has two longitudinal ribbons, which are parts of the original outer cylindrical finger forming, located in a plane passing through the large diagonal of the said rhombus, perpendicular to the line drawn through the centers of the fingers.

EFFECT: increase in the manufacturability and reliability of work.

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Description

The invention of the docking device relates to mechanical engineering, namely to industrial robots and manipulators designed to work with replaceable working bodies - tools and grips installed in tool stores or cassettes.

Known docking device (A.S. SU No. 1301697, IPC B25J 15/04), containing connecting disc-shaped elements fixed on the end link - the manipulator hand and on the body of the working body (gripper or tool), two landing elements in the form of pins (fingers ) with beveled grooves installed on one connecting element, mirrored to the base (landing) holes made on the other.

As a prototype, a device for changing gripping devices (grippers) was selected, the design of which is given in the book: Robotic systems in assembly production / Ed. E.V. Pashkova - K.: Vischa shk. Head publishing house, 1987. - P. 81, fig. 3.11, c. The device contains connecting elements in the form of flanges, the centering of which relative to each other is carried out with the help of fingers and holes for them located in a mirror image. Two pins are tapered for preliminary centering, and two are cylindrical for final centering. The flanges are fixed to each other using a central round electromagnet with a hole in the core for a round electrical connector or a compressed air connection.

The main disadvantage inherent in the docking devices for interchangeable tools or gripping bodies shown as an analogue and prototype is that in order to reliably mate the cylindrical fingers with the holes, it is necessary to either ensure that the center-to-center distances between the fingers and the holes are performed with high accuracy, which complicates the technological process and leads to an increase in time and material costs, or an increase in the guaranteed clearance in the "finger-hole" connection, which reduces the positioning accuracy of the tool or gripper.

In addition, in the design of the docking device, selected as a prototype, the center-to-center distance between the centering fingers diametrically installed in the body (magnetic circuit) of the electromagnet will change due to thermal deformation arising under the influence of heat generated during the operation of the electromagnet, which will lead to a decrease in the reliability of the docking, and since there is no anti-magnetic screen between the armature of the electromagnet included in the composition of, for example, the gripper, the magnetic flux will dissipate, causing, firstly, a decrease in the traction force, which determines the reliability of the docking (fixation), and secondly, the magnetization of the ferromagnetic parts of tools and grips (residual magnetism), which also negatively affects the reliability of the device and narrows the technological capabilities.

The goal achieved with the help of the proposed invention of the docking device is to improve manufacturability and reliability of operation by reducing the requirements for the accuracy of the relative position of the centering (locating) elements and reducing the losses of the magnetic flux created by the electromagnet, which determines the magnitude of the traction force, and, consequently, the reliability of fixation connecting elements relative to each other.

The achievement of this goal is ensured by the fact that in the docking device for installing and fixing replaceable tools and grippers located in the store on the end link of the industrial robot manipulator, containing facing one another the connecting surfaces of the connecting elements with mirrored centering elements in the form of fingers and holes for them, fixing connecting elements between themselves electromagnet and switching connectors on the mating surfaces for connecting tools and grips with energy sources, the following technical solutions were used:

- the end link of the manipulator and the bodies of tools and grippers are equipped with connecting platforms made of non-magnetic material;

- on the docking surface of the end link of the manipulator, two holes are made, in which electromagnets with a retractable armature are coaxially installed;

- the casings of the electromagnets are made in the form of cups with lids made of ferromagnetic material, the latter being made in one piece with the cores of the coils installed inside the casings;

- the cores of the coils have collars on their flat ends, shunting the magnetic flux;

- the bottoms of the cups facing the fingers have central holes with guide chamfers, which are centering elements for fingers of ferromagnetic material fixed on another platform, equipped with flanges with an outer diameter equal to the diameter of the electromagnet body;

- pins with flanges are retraction armatures of electromagnets;

- one of the fingers is cylindrical, and the other, made with a cross-section in the shape of a rhombus, has longitudinal ribbons, which are parts of the original outer cylindrical generatrix of the finger, located in a plane passing through the large diagonal of the said rhombus, perpendicular to the line passing through the centers of these two fingers ...

Between the totality of the claimed features of the invention and the expected technical results obtained using the proposed docking device, there is the following causal relationship.

First, making one of the centering pins with a diamond-shaped cross-section, i. E. rhombic, and its installation on the connecting platform relative to the other pin in such a way that the large diagonal of the rhombus is perpendicular to the line passing through the centers of these fingers, allows you to reduce the requirements for the accuracy of obtaining a given value of the center distance between material costs, while ensuring the necessary reliability of mating the fingers with the holes for them and the required positioning accuracy of the replaceable tool or gripper in the working area.

Secondly, the implementation of the connecting platforms from a non-magnetic material, for example, an aluminum alloy, i.e. imposing the functions of anti-magnetic shields on them, avoids the scattering of magnetic flux and magnetization (residual magnetism) of the ferromagnetic parts of the tool, the gripper and the end link of the robot manipulator, which reduces the amount of traction force, which determines the reliability of fixing the platforms to each other and performing the technological tasks assigned to them.

Thirdly, supplying the flat end surface of the electromagnet core with a shunt collar helps to increase the traction force in the end position of the armature inside the coil, and, consequently, to increase the reliability of fixing the platforms to each other and to achieve the required positioning accuracy of tools and grippers.

FIG. 1 shows a diagram of the relative location of the connecting platforms of the tools (grippers) and the end link of the manipulator; in fig. 2 is a section along a-A in Fig. one; in fig. 3 is a view along arrow B in FIG. 1, diagram for determining the size of the rhombic finger ribbon; in fig. 4 is a diagram for determining the error of installing replaceable tools (grippers) on the connecting platform of the end link of the manipulator.

The docking device contains connecting platforms 1 and 2 made of non-magnetic material, for example, an aluminum alloy (Fig. 1), which are constituent parts, respectively, of the end link 3 of the robot manipulator and bodies 4 of interchangeable tools (grippers).

On the docking surface of the platform of the end link of the manipulator, two holes 5 with a diameter D are made with a center-to-center distance L1, and centering pins 6 and 7 with a diameter of D _p with flanges 8 with a diameter of D _f = D are installed on the facing docking surface of another platform with an center-to-center distance L2 = L1 , the first of which is cylindrical, and the second is rhombic, i.e. having a cross-section in the shape of a rhombus, which are at the same time retraction anchors of electromagnets 9 fixed in the openings of the platform of the end link of the manipulator (Fig. 2), and the large diagonal of the rhombus is located in a plane perpendicular to the line drawn through the centers of these fingers (Fig. 3). In the same plane, there are two longitudinal, i.e. along the length of the finger, ribbons 10 with a width of 2e, which are parts of the original outer cylindrical generatrix of a rhombic finger with a diameter of D _p .

Each of the electromagnets with a retractable armature contains a housing 11 in the form of a cup with a diameter D _e = D forming a ferromagnetic stator and a cover 12 made integral with a core 13, the flat end of which is equipped with an annular shunt collar 14. The core is placed inside a coil 15 installed in the electromagnet housing.

In the bottom parts of the electromagnet cases facing towards the centering fingers, centering holes 16 with guide chamfers are made, the center-to-center distance between which is equal to the center-to-center distance L1 between the holes in the platform for installing and fixing the electromagnets.

To supply electrical energy to tools and grips, mating parts of the electrical connector 17 and the pneumatic connector 18 are installed in the connecting platforms.

The docking process proceeds as follows.

When moving the connecting platform 1 with the help of the manipulator towards the connecting platform 2 located opposite to each other until their mating surfaces are fully in contact with each other, the centering pins 6 and 7 are inserted into the corresponding centering holes 16 in the bottom parts of the housings 11 and into the holes of the coils 15 of the electromagnets 9, as well as connection of the contacts of the electrical connector 17 and the mating parts of the pneumatic connector 18. In this case, the ends of the fingers (anchors) are located with a minimum guaranteed clearance relative to the annular shunt collar 14 at the end of the core 13. Then an electric voltage is applied to the windings of the coils, causing the formation of a magnetic flux Ф, creating a traction force F, which carries out the final fixation between the connecting platforms.

The presence of flanges 8 and an annular shunt collar 14 on the core on the centering pins (anchors) contributes to an increase in the traction force F at the end of the insertion of the fingers into the coils, and, consequently, to an increase in the reliability of platform joining (Pashkov E.V., Osinsky Yu.A., Chetverkin A .A. Electro-pneumoautomatics in production processes: Textbook. - Sevastopol: Publishing house of Sev GTU, 1997. - S. 252-254; L.A. Kazakov Electromagnetic devices REA: Handbook. - M .: Radio and communication, 1991 . - 352 p.).

With a constant value of the center-to-center distance L1 between the centering holes 16 and diameters of constant size D _{0, the} high accuracy of which is achieved using relatively simple and low-cost technological processing processes (deployment and external grinding), the high reliability of the mating of the fingers with the holes for them mainly depends on the accuracy of the center-to-center distances between the grips, which requires more expensive technological equipment and processing tools, which leads to an increase in material costs.

Making one of the centering fingers rhombic significantly reduces material costs, since in this case the accuracy of the center-to-center distance between the fingers can be significantly reduced without reducing the reliability of mating the fingers with the holes.

The width of the ribbons of the cross-section of the rhombic finger (Fig. 4) is determined as follows (Korsakov B.C. Fundamentals of designing devices in mechanical engineering. - M .: Mechanical engineering, 1965. - S. 59-62).

From triangles okn and omn

R ₀ ² - (c + e) ² = (R ₀ -Δ) ² -e ² ,

where

e = (2R ₀ Δ-Δ ² -c ² ) / 2c.

Replacing 2R ₀ = D ₀ and taking Δ ² = 0, since this quantity is of the second order of smallness, we obtain

2e = (D ₀ Δ ') / 2c-c,

where Δ '= 2Δ is the diametral clearance.

In turn,

2с = δ + δ'-2Δ ₁ ,

where δ is the tolerance for the center-to-center distance L1 between the centering holes;

δ '- tolerance for the center-to-center distance L2 between centering pins;

2Δ ₁ - diametrical clearance in the connection of the cylindrical pin with the hole.

The last expression makes sense under the condition

δ + δ ^' > 2Δ ₁ ,

the use of which makes it possible to determine the condition for justifying the value of the tolerance for the center-to-center distance L2, which will ensure the required positioning (basing) accuracy of the tool (gripper):

δ'≥2Δ ₁ -δ.

The displacement of the platform of the replaceable tool (gripper) from its middle position in the directions perpendicular to the axis of the cylindrical pin (Fig. 4) is determined by the minimum radial clearance Δ ₁ , the tolerance for the diameter of the mating hole δ ₁ and the tolerance for the diameter of the finger δ ₁ '.

The smallest displacement is Δ ₁ , and the largest is

Δ ₁ + δ ₁ '/ 2 + δ _1/2 .

The offset value is used to determine the error in setting the tool (gripper) for certain sizes (diameters) of fingers and holes for them.

The largest possible skew angle α of the tool platform (at its small values)

sin α≈α = (Δ ₁ + δ _1/2 + δ _1/2 + Δ + δ _2/2 + δ ₂ '/ 2) / L1,

where L1 is the center-to-center distance between the centering holes;

Δ is the minimum radial clearance at the junction of the rhombic pin with the hole;

δ ₂ - tolerance for the diameter of the hole for the rhombic pin;

δ ₂ '- diameter tolerance (by ribbons) of a rhombic pin.

Claims (1)

A docking device for installing and fixing replaceable tools and grips located in the store on the end link of an industrial robot manipulator, including facing one another connecting surfaces of connecting elements with mirrored centering elements in the form of fingers and holes for them, fixing the connecting elements between themselves an electromagnet and switching connectors on the docking surfaces for connecting tools and grips with energy sources, characterized in that the end link of the manipulator and the bodies of tools and grips are equipped with connecting platforms made of non-magnetic material, two holes are made on the docking surface of the platform of the end link of the manipulator, in which electromagnets are coaxially installed with a retractable armature, the ferromagnetic cases of which in the form of cups are equipped with lids made in one piece with the cores of the coils installed inside the cases and equipped with shunt collars on the p the flat ends of the said cores, the bottoms of the cups facing the fingers, have central holes provided with guide chamfers, which are centering elements for two ferromagnetic fingers, equipped with flanges with diameters equal to the outer diameter of the electromagnet casings fixed on another platform, which are the retraction anchors of the said electromagnets, one made of fingers is cylindrical, the other finger, made with a cross-section in the shape of a rhombus, has two longitudinal ribbons, which are parts of the original outer cylindrical generatrix of the finger, located in a plane passing through the large diagonal of said rhombus, perpendicular to the line drawn through the centers of the fingers.

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