PL241393B1 - Adaptive ball-and-socket joint - Google Patents

Abstract

The subject of the invention is an adaptive ball joint intended for use in robot joints, in particular in joints of walking robots, exoskeletons and humanoid robots operating in conditions of high stability of staying in a certain position and reducing resistance to movement during movement. An adaptive ball joint having an upper assembly and a lower assembly. The upper assembly includes a ball pin (1) ended with a ball in which a spring pin (7) is seated which ends with a spherical element (8). The lower unit includes a spindle (4), a cylindrical housing that has side holes (10). In the side holes (10) sliding rings (13) are slidably mounted, which, through a compression spring (14) and pressure screws (15), are slidingly connected to the ball. There is a conical hole (12) in the spindle (4), in which the spherical element (8) of the spring pin (7) is placed. The joint has the ability to pre-adjust the change in the value of play and resistance to movement. The design of the joint ensures the automatic return of the upper unit and the lower unit to the initial position.

Description

PL 241 393 B1

Description of the invention

The subject of the invention is an adaptive ball joint intended for use in joints of robots, in particular walking robots, exoskeletons and humanoid robots operating in conditions of high stability of staying in a certain position and reducing resistance to movement during movement. The invention is used in technical systems where high motion stability is required, especially in robotics, multi-legged robots, humanoid robots, measuring devices, manipulators and industrial robots.

A ball joint is known in the prior art, e.g. from Polish patent No. 211105, which has a spherical part, a fixed part and a protective-sealing unit, which is a cap cover with a two-stage seat with embedded sealing elements adjacent to the surface of the spherical part of the joint.

European patent no. EP 0481212 shows a ball joint having a spherical head, a joint pin and a ball connecting pin housed in a coupling holder with a vessel-shaped interior in which it can be pivoted. The ball joint is slide-mounted in a bearing attached to the coupling mount.

Another ball joint according to the patent no. 198014, is characterized in that it consists of two parts, the second part of which has a spherical opening snap-fitted to the first spherical part with a protruding neck having a hemispherical skirt slidable on the outer surface of the spherical opening, wherein the lumen diameter of the spherical opening is smaller than that of the sphere, and the ball with the extending neck is made of a single material.

From the US patent specification US 8714862 a ball joint is known having a disc spring in an annular recess in an axially loaded lower sliding seat. The disc spring is used to preload and compress the top seat down towards the spherical end of the head. Preloading prevents the axial or rotational movement of the ball pin until a minimum load is applied to exceed the preload and cause movement.

The articulation of US Patent No. 9291195 discloses a ball joint assembly in which the pin ball portion is housed within a cup-shaped bearing bushing and the shaft portion of the ball portion protrudes from the open interior through the open end of the housing for engagement with another member. The lower bearing is housed within the bearing bushing and includes an extension that extends into the bore of the bearing bushing that holds the lower bearing in a predetermined position within the bearing bush.

The universal ball joint according to US Patent No. 8353776 comprises a first rotary body and a second rotary body pivotally connected to each other. The first rotary body includes an elliptical head and a connecting portion. The head has a major axis and a minor axis perpendicular to the major axis. The second rotating body defines an elliptical ball seat rotatably engaged with the head of the first rotating body such that the head can rotate about a major axis or minor axis of the head.

The prior art ball joint according to US Patent No. 6,533,491 is characterized in that the lower bearing defines a lower bearing surface surrounding the spherical head on the bore side of the housing and an opposite upper movable bearing defines the upper bearing surface, the upper bearing being biased by a spring against the spherical head so as to be able to move towards the lower bearing when the spherical head or lower bearing is worn out.

Another ball joint according to US Patent No. 7083356 has a ball joint with an angular movement restriction system that allows free rotational movement of the ball pin, but at the same time limits the angular movement of the same ball-type pin in a predetermined direction. The restraint system of the preferred embodiment is used in steering or linkage rods where rotational movement with respect to its longitudinal axis is undesirable.

European patent EP 1662158 discloses a ball joint having a seat with a housing housing the ball-shaped joint part and allowing its sliding movement. The holder of the housing is configured to inhibit mutual movement between the holder and the seat. The hinge comprises a frustoconical member in the holder and a congruent part of the cone in the seat. Further, the holder and the socket have grooved surfaces engaging each other for: securing the housing to the socket; preventing relative movement between the housing and the seat, and sealing the first peripheral contact surface between the housing and the seat.

PL 241 393 B1

There are also prior art solutions showing a pneumatic spring with a ball joint according to EP 1797346. This solution comprises a ball joint which has a spheroidal bearing element in the bearing shell. The bearing shell is adjustable on the spheroidal bearing element by means of a clamping element.

The prior art also discloses a ball joint described in Patent Application No. P.419462. This joint consists of a plastic shell and a metal ball pin, seated in the joint seat of the metal body. A resilient pressure ring adheres to the bottom of the bushing through a metal washer, compressed by a plug closing the joint seat, which, due to internal pressure stresses of the system, constantly presses against the bushing, eliminating play in the joint.

The known art ball joint described in patent no. EP 0075414A1, in which the head of the ball pin is mounted in a bearing ring in a seat. The bearing sleeve is surrounded by a compressed elastomeric sleeve that surrounds the bearing ring at the equatorial region of the head to press the ring against the head to apply a torque load. The torque load can be changed by changing the hardness of the elastomeric material of the sleeve.

Another known solution is a ball joint according to US Patent No. 3,951,557, in which a split plastic bearing is brought into contact with the ball by the action of a spring which is held in the bore by the cover plate.

Another known solution is a ball joint disclosed in US Patent No. 6,010,271 having only one hole through which all items are installed during assembly and through which the pin protrudes. These components include a compression spring, a polymer lower bearing, a spindle, and a metal upper bearing. The circumferential edges of the hole are rotated or rolled to hold components in place and compress the compression spring.

Also known in the art is a compression ball joint according to Patent No. EP 1866552 using a split top bearing shaped to provide a bearing surface for the top and side of the ball pin and to allow full engagement with the housing and the ball pin simultaneously.

In the light of the known art, the invention, which is an adaptive ball joint, solves the problem of building joints for multi-legged walking robots and building kinematic nodes cooperating with exoskeleton elements. More specifically, the invention solves the problem of constructing and operating adaptive ball joints for use in micromechanisms. Currently, there are no known solutions in the state of the art that would allow to adjust the resistance to movement and the play in a spherical joint. Moreover, in these solutions it is not possible to obtain a uniform pressure between the mating surfaces of the joint so as to ensure adequate stability of operation. In the solutions known from the state of the art, it is impossible to automatically return the working elements of the joint to the initial position after the load has ceased.

Accordingly, the Applicant has developed a solution that overcomes the shortcomings and imperfections of the prior art solutions.

The essence of the invention is an adaptive ball joint having an upper assembly including a ball pin terminated in a ball having a spherical surface which is movably mounted in a lower assembly containing the pin. The adaptive joint according to the invention is characterized in that the ball of the ball pin has a flat surface perpendicular to the axis of the ball pin on the pin side. The ball has a hole in the axis of the ball pin on the side of the flat surface, in which a spring pin ending with a spherical element is mounted. The lower unit has a cylindrical housing having side openings which on the side opposite to the ball pin has a cylindrical taper to which, on the inside, the pin is threadedly connected. The pin on the side of the ball pin has a conical hole in which a spherical element is placed, and sliding rings are slidably mounted in the side holes. The slip rings are slidingly connected to the spherical surface of the ball by means of a pressure spring and pressure screws.

Preferably, the slip ring has an insert, the insert having a concave surface.

It is particularly advantageous if the concave surface of the insert has a radius corresponding to the radius R of the sphere.

PL 241 393 B1

Preferably, a resilient pin, seated in the bore, is threadedly engaged with the ball of the ball pin.

Preferably, the side openings are at equal angular distances from the axis of the cylindrical housing.

Preferably there are at least three side openings.

Preferably, the axes of the side openings intersect at the center S of the joint rotation.

It is particularly advantageous if the axes of the side openings lie on a single straight plane π or lie on a single conical plane.

Optionally, in the side holes, there are rolling rings with a circumferential groove in which the balls are placed.

It is especially advantageous if the balls are embedded in the basket.

Preferably, a non-elastic pin is mounted in the bore, on which a spiral spring ending with a spherical element is mounted.

The design of the adaptive ball joint ensures that it can be turned in any direction. The joint according to the invention, in some solutions, has elastic elements which allow increasing the angle of deflection of the whole joint. Thanks to the elastic elements, after the load has ceased to act, it is possible for the joint to set itself back to its initial position.

According to the invention, the adaptive ball joint comprises two units, i.e., an upper unit and a lower unit. The top unit has a ball pin at the end of a ball that is limited in its lower part by a flat surface. An elastic pin ending with a spherical element is screwed into the threaded hole of the ball pin. The lower unit comprises a cylindrical housing which is threadedly engaged in the lower part with a mandrel having an internal conical bore. Slip rings, which can be equipped with inserts, are slidably mounted in the side openings of the housing, spaced at equal angular intervals along the circumference. The inserts have a concave surface with a radius R and they slide in contact with the spherical surface of the ball pin. In this case, the slip rings are pressed against the pressure springs, the pretension of which is regulated by pressure screws. The axes of the slip rings intersect at the center S of the joint rotation and lie in the π plane or lie on the cone surface when they are not horizontal. The spherical element of the elastic pin, threaded into the threaded hole of the ball pin, starts to contact the surface of the conical hole from a certain angle α of the joint deflection. This depends on the position of the pin with an internal conical bore in relation to the ball element and is defined as the height h. As a result of a further increase in the articulation angle α, the elastic pin begins to deform in the radial direction. However, after the forces driving the deformation of the elastic pin have ceased, it is possible to return the joint according to the invention to its initial position, i.e. that in which no deformation forces occurred. Moreover, for the height h> = hmax, the contact of the spherical spring element of the pin with the inner surface of the conical hole in the pin occurs for any angle α of the joint deflection. The operating principle of the adaptive ball joint according to the invention is also based on the fact that the joint has the possibility of presetting the change in the value of the play and the resistance to movement. This is done thanks to pressure screws and pressure springs. In order to change the resistance to movement, it is also possible to use rolling rings instead of slip rings.

The advantage of the inventive ball joint is its adaptability to changing operating conditions. The adaptive ball joint has the ability to adjust the play and resistance to movement in the connection of slip rings or rolling rings with the spherical surface of the ball pin, ensuring the rotation of the adaptive ball joint in any direction. Moreover, the advantage of the invention is the maintenance-free operation of the joint for sliding pairs of steel type (ball pin) - PTFE FRP (slip ring reinforced with a polymer glass fiber insert containing polytetrafluoroethylene) or rolling friction between the spherical surface of the adaptive ball pin and the rolling elements of the roller ring.

Accordingly, the technical problems resulting from the solutions disclosed in the prior art have been solved by the joint according to the invention.

The swivel and oscillating joint is shown in the examples and in the drawing where:

Fig. 1 is a front view of the adaptive ball and socket joint according to a first embodiment;

PL 241 393 B1

Fig. 2 shows an axial section of the adaptive ball joint of Fig. 1 along the line A-A;

Fig. 3 shows a cross-sectional view of the adaptive ball-joint of Fig. 1 along a line

B-B;

Fig. 4 is an isometric view of the adaptive slip ring ball joint with a quarter cutout;

Fig. 5 is a spatial view of the adaptive ball / socket joint housing with a quarter cutout;

Fig. 6 is a front view of the resilient pin;

Fig. 7 is a view of the adaptive ball-and-socket joint in a tilted position of the upper assembly;

Fig. 8 is a view of an adaptive ball joint with an elastically deformed spring pin in a tilted position of the upper assembly;

Fig. 9 is a front view of the adaptive ball and socket joint according to a second embodiment;

Fig. 10 shows an axial section of the adaptive ball / socket joint of Fig. 9 along the line C-C;

Fig. 11 is a cross-sectional view of the adaptive ball and socket joint of Fig. 9 along the line D-D;

Fig. 12 is a half view and half sectional view of the roller ring;

Fig. 13 shows a spatial view of a rolling ring;

Fig. 14 is a front view of the adaptive ball and socket joint according to a third embodiment;

Fig. 15 shows an axial section of the adaptive ball / socket joint of Fig. 14 along the line E-E;

Fig. 16 is a sectional view of the adaptive ball-joint according to the third embodiment in a tilted position of the top;

Fig. 17 shows a spatial view of the insert in a partial section;

Fig. 18 shows a 3D view of the insert in a 3D view.

Exemplary performance 1

In a first embodiment, an adaptive ball joint (Figures 1, 2, 3 and 4) is shown which has an upper assembly and a lower assembly. The upper unit comprises a ball pin 1 terminating in a ball 2 which has a spherical surface 3. The ball pin 1 is seated in the lower unit, the ball pin 1 being movable in the lower unit. The ball 2 of the ball pin 1 has a flat surface perpendicular to the axis of the ball pin 1. On the side of the flat surface 5, the ball 2 has a hole 6 located in the axis of the ball pin 1. it ends with a spherical element 8. The spring pin 7 (Fig. 6) is made of the Ti6 14U-PE-UHMW titanium alloy. The lower unit comprises a pin 4 which is threaded into the cylindrical housing 9 (Fig. 5). The housing 9 on the portion where it joins the pin 4 has a cylindrical taper 11. The housing 9 above the cylindrical taper 11 is wider and has three side openings 10 62 mm in diameter. The axes of the side openings 10 intersect in the center S of the joint rotation and lie in one straight plane π. The holes 10 are spaced at equal angular distances in relation to the longitudinal axis of the cylindrical housing 9. Each hole 10 has a sliding ring 13 slideably mounted, which, through a compression spring 14 and a pressure screw 15, is slidingly connected to the spherical surface 3 of the ball 2. Each of the three of the slip rings 13, on the side of the ball 2, has an insert 17 which has a concave surface 16 (FIG. 17), the radius R of the concave surface 16 of the insert 17 corresponding to the radius of the sphere 2. The radius R is 57 mm. The inserts 17 are made of glass fiber containing polytetrafluoroethylene. The inserts 17, slip rings 13, compression spring 14 and pressure screws 15 provide adjustment of play and resistance to movement of the ball 2 of the ball pin 1. The pin 4 on the side of the ball pin 1 has a conical hole 12, the depth of which is 52 mm. In this embodiment, the spherical element 8, which ends with the spring pin 7, is halfway down the conical opening 12. The adaptive ball joint in the first embodiment, except for the insert 17, is made of steel.

In this embodiment, when a force is applied, the tilt angle α of the ball pin with respect to the longitudinal axis of the adaptive ball joint when the ball element 8 begins to touch the inner surface of the tapered opening 12 is ± 10 ° (Fig. 7). Keep applying strength

The PL 241 393 B1 causes an elastic deformation of the elastic pin 7, so that the deflection angle α of the ball pin 1 becomes ± 18 ° (Fig. 8).

It was verified that after the force had ceased, the upper and lower units automatically returned to their position when the ball element 8 first contacted the inner surface of the conical opening 12.

P roduction example 2

In the second embodiment, shown in Figs. 14, 15 and 16, an adaptive ball joint is shown as in the first embodiment, with the difference, however, that the spring pin 7 is replaced by a non-elastic pin 22 which is made of Ti6 14U titanium alloy. -PE-UHMW. A spiral spring 23 is mounted on the inelastic pin 22. A ball element 8 in the form of a metal mushroom is mounted on the other end of the spiral spring 22. In this embodiment, the element 8 is at its deepest point in the conical opening 12, which corresponds to hmax = 55 mm. The tilt angle α of the ball pin 1 relative to the longitudinal axis of the adaptive ball joint is in this embodiment ± 17 °.

W eel example 3

In a third embodiment, shown in Figs. 9, 10 and 11, an adaptive ball joint is shown, the structure of which is similar to that of the first embodiment, except that the slip rings 13 have been replaced by roller rings 18 (Fig. 12 and 13). The rolling rings have a groove 19 into which the balls 20 are placed. The balls 20 have a diameter of 5 mm. The balls 20 in the groove 19 are kept equidistant from each other by the cage 21.

Execution example 4

In the fourth embodiment, an adaptive ball joint is shown, the structure of which is similar to that of the first embodiment, with the difference, however, that the spring pin 7 has been replaced by an inelastic pin 22 (Figures 15 and 16) on which a spiral spring 23 is seated. 22 is made of steel and ends with a spherical element 8 in the form of a steel mushroom. In this embodiment, the spherical element 8 is at its shallowest position in the conical opening 12, which corresponds to a height hmin = 2 mm (Fig. 16). The swivel angle α of the joint in the position where the spherical element 8 meets the internal surface of the conical opening 12 is ± 10 °. As a result of the further action of the force, an elastic deformation of the spiral spring 23 takes place in the direction perpendicular to the longitudinal axis of the joint, which allows for a greater deflection angle α of the joint, equal in this example to ± 17 °.

Performance example 5

In a fifth embodiment, an adaptive ball joint is shown, the structure of which is similar to that of the first embodiment, but with the difference that the axes of the side holes 10 lie on a single conical plane.

List of symbols ball pin ball spherical surface pin flat surface spring hole spherical pin element

Case

Side openings

Cylindrical taper

Conical hole

Slip rings

Compression spring

Pressure screws

Concave surface

Inserts

Rolling rings

Claims (11)

PL 241 393 B1 19 Groove 20 balls 21 Shopping cart 22 Inelastic pin 23 Spiral spring. Patent claims 1. An adaptive ball joint having an upper assembly comprising a ball pin (1) terminating in a ball (2) having a spherical surface (3), is mounted movably in a lower assembly comprising a pin (4) characterized in that the ball (2) ball pin (1) of the upper assembly, on the side of the pin (4) has a flat surface (5) perpendicular to the axis of the ball pin (1) and the ball (2), on the side of the flat surface (5) has a ball pin ( 1), a hole (6) in which a spring pin (7) ends with a spherical element (8), and the lower unit has a cylindrical housing (9) having side holes (10), which on the side opposite to the ball pin (1) has a cylindrical narrowing (11) to which, from the inside, the pin (4) is threaded, the pin (4) on the side of the ball pin (1) has a conical hole (12) in which the spherical element (8) is placed , and in the side holes (10) there are slidably mounted rings sliding (13) which, through the pressure spring (14) and pressure screws (15), are slidingly connected with the spherical surface (3) of the ball (2). 2. Adaptive ball joint according to claim A device as claimed in claim 1, characterized in that the slip ring (13) has an insert (17), the insert (17) having a concave surface (16). 3. Adaptive ball joint according to claim The method of claim 2, characterized in that the concave surface (16) has a radius corresponding to the radius R of the sphere (2). 4. Adaptive ball joint according to claim The method of claim 1, characterized in that the spring pin (7), seated in the hole (6), is threadedly connected to the ball (2) of the ball pin (1). 5. Adaptive ball joint according to Claim A method as claimed in claim 1, characterized in that the side openings (10) are equally angularly spaced from the axis of the cylindrical housing (9). 6. The adaptive ball joint as recited in claim 6. The method of claim 1, characterized in that it has at least three side openings (10). 7. The adaptive ball joint as recited in claim 7. The joint as claimed in claim 1, characterized in that the axes of the side openings (10) intersect at the center S of the joint rotation. 8. The adaptive ball joint as recited in claim 8. The method of claim 7, characterized in that the axes of the side openings (10) lie on a single straight plane π or lie on a single conical plane. 9. The adaptive ball joint of claim 1. Roller rings (18) having a circumferential groove (19) in which the balls (20) are placed in the side openings (10). 10. Adaptive ball joint according to Claim The method of claim 9, characterized in that the balls (20) are seated in a basket (21). 11. The adaptive ball joint of claim 11. A spring (23) ending in a spherical element (8) is mounted in the bore (6).