BALL

Background of the invention The invention relates to a multidirectional driving ball according to the preamble of claim 1. The invention further relates to a method for rotating a spherical ball of a multidirectional driving ball to obtain a displacement between said spherical ball and a contact surface engaging a surface of said spherical ball in a contact point. Description of the Related Art

Multidirectional driving balls are known in the art as a spherical ball comprising means for being driven is several directions and is e.g. used for driving an object being transported on a conveyer or as drive "wheels" in various types of self- propelled vehicles. However, a known problem is that if the ball is driven by more than one driving rollers some of these rollers will be exposed to a more or less transversal motion of the ball in relation to the rotational direction of the rollers, which will reduce the efficiency of the driving ball and increase the wear of the ball and/or the rollers. This transversal motion is particularly a problem with multidirectional driving balls because this drive type will pick up dirt or foreign objects by the ball surface and transport it into the drive means of the driving ball where the transversal motion and e.g. grains of sand will produce a grinding effect which will rapidly accelerate the wear of the ball and/or the rollers. E.g. from US 5,261,526 it is known to use multidirectional driving balls as the drive means in a conveyer. Each driving ball can be rotated by e.g. three driving rollers and the problem regarding frictional wear from the transversal motion is solved as follows: "The internal friction in this system between the ball and the driving rollers is at a minimum, if ... the ball rotates on an axis in the horizontal plane " But even if the transversal motion is kept at a minimum the grinding effect will still rapidly wear the ball or the rollers.

Another way to solve this problem is disclosed in EP 0 952 945 Bl in which the spherical ball is driven by one or more omnidirectional wheels enabling that the rollers arranged on the wheels periphery at least to some degree will accept the transversal motion. However, the solution is both complex and expensive and it will not completely eliminate the grinding effect. An object of the invention is therefore to provide for a durable and cost-efficient multidirectional driving ball and an advantageous technique for rotating a spherical ball of a multidirectional driving ball.

The invention

The invention provides for a multidirectional driving ball comprising a hollow spherical ball part. The multidirectional driving ball is characterised in that the hollow spherical ball part comprises rotor magnets arranged inside the hollow spherical ball part to form a rotor of an electrical motor driving the rotation of the multidirectional driving ball.

Attaching magnets to the inside of hollow spherical ball part to make it act as a rotor of an electrical motor is advantageous in that it provides for a very efficient ball drive with very little loss. Furthermore, forming the hollow spherical ball part as the rotor of an electrical motor provides for a very simple and inexpensive multidirectional driving ball which can be made in very small diameters.

It should be noted that the term "the hollow spherical ball part comprises rotor magnets arranged inside the hollow spherical ball part" both includes that the magnets can attached to the inside surface of the spherical ball or integrated in the inside surface of the spherical ball e.g. by selectively magnetising areas of the inside surface of the ball - if it was made of a magnetisable material - or by building the magnets into the inside surface of the ball. In an aspect of the invention, said rotor magnets are permanent magnets.

It is difficult and complex to conduct an electrical current across the rotatable connection between the rotor and the stator and it is therefore advantageous to form the rotor magnets as permanent magnets.

In an aspect of the invention, a stator of said electrical motor is also arranged inside said hollow spherical ball part.

Also arranging the stator inside the hollow spherical ball part is advantageous in that the stator is well protected inside the ball part and in that it provides for a compact and inexpensive design.

In an aspect of the invention, said stator comprises at least two circular rows of stator magnets.

Providing the stator with at least two circular rows of stator magnets is advantageous in that it hereby is possible to tilt the rotational axis of the rotor in relation to the symmetry axis of the stator so that the rotational axis of the rotor is also tilted in relation to a contact surface - against which the multidirectional driving ball rolls - and hereby create a relative motion between the ball and the contact surface.

Furthermore, every motor is in principle also a generator and the faster the motor rotates the more Electromagnetic Force (EMF) it creates. The EMF increases with the speed, because of Faraday's law. So, if the motor has no load, it turns very quickly and speeds up until the EMF, plus the voltage drop due to losses, equal the supply voltage. The size of the EMF is among other determined by the overlapping area of the rotor ant the stator. When the spherical ball starts to rotate around a vertical axis this overlap is maximal - thus, the torque is also maximal but the highest possible rotational speed is relatively low. When the spherical ball - and thereby the rotor - is tilted the overlap becomes smaller. As the overlap becomes smaller the torque is also reduced but the highest possible rotational speed is increased. This is advantageous in that the present driving ball design hereby provides the most torque when it is needed - i.e. at start-up - and it enables the highest top speed when it is needed - i.e. when the ball is tilted the most to drive fast.

In an aspect of the invention, said stator magnets are individually engageably electro magnets.

Hereby is achieved an advantageous embodiment of the invention.

In an aspect of the invention, said hollow spherical ball part is connected to said stator by means of a ball joint.

Connecting the hollow spherical ball part with the stator through a ball joint is advantageous in that the ball joint allows the rotational axis of the hollow spherical ball part to. be tilted in relation to the centre axis of the stator whereby the hollow spherical ball part can rotate on the contact surface, thereby creating a relative motion between the contact surface and the hollow spherical ball part. In an aspect of the invention, a shaft part of said ball joint is rotatably connected to said hollow spherical ball part.

The shaft of the ball joint provide for a simple and efficient location for rotating connection between the stator and the hollow spherical ball part in that the shaft part in a simple and effective manner could be provided with one or more bearings allowing the relative rotation.

In an aspect of the invention, said rotor is arranged directly on the inside surface of said hollow spherical ball part.

Arranging the rotor magnets directly on the inside surface of the hollow spherical ball is advantageous in that no further means are needed for forming a rigid rotor part, thereby providing for a simple and inexpensive motor design.

In an aspect of the invention, an inside surface area and an outside surface area of said hollow spherical ball part has mutually different properties regarding hardness and/or roughness. In an aspect of the invention, said hollow spherical ball part further comprises an inflatable tyre arranged at an outside surface of said hollow spherical ball part.

Providing the outside surface of the spherical ball with an inflatable tyre is advantageous in that the inflatable tyre provides for better contact with the contact surface and because is will reduce the noise and vibrations emitting from the spherical ball.

In an aspect of the invention, said multidirectional driving ball further comprises a control unit adapted to engage at least one stator magnet of a first circular row of stator magnets of said at least two circular rows of stator magnets and at least one stator magnet of a second circular row of stator magnets of said at least two circular rows of stator magnets to tilt said rotor in relation to said stator.

Hereby is provides simple and inexpensive means for tilting the rotational axis of the spherical ball i.e. the rotor in relation to the stator. In an aspect of the invention, the outside diameter of said rotor is substantially equal to the inside diameter of said hollow spherical ball part.

The rotor design provides for efficient use of the available space inside the hollow spherical ball and furthermore the larger the rotor diameter is the higher torque the motor can produce. Thus, making the rotor as big as physically possible inside the spherical ball provides for the most efficient motor design.

The invention further provides for a method for rotating a hollow spherical ball part of a multidirectional driving ball to obtain a displacement between the spherical ball part and a contact surface engaging an outside surface of the spherical ball part. The method comprises the steps of:

• arranging a plurality of rotor magnets at the inside surface of the hollow spherical ball part to form a rotor of an electrical motor,

• placing a plurality of stator magnets inside the rotor to form a stator part of the electrical motor, and

• alternately engaging the rotor magnets and/or said stator magnets to drive a relative displacement between the rotor and the stator and thereby rotate the hollow spherical ball part.

Hereby is achieved an advantageous embodiments of the invention.

It should be noted that the term "arranging a plurality of rotor magnets at the inside surface" both includes that the magnets can attached to the inside surface of the spherical ball or integrated in the inside surface of the spherical ball e.g. by selectively magnetising areas of the inside surface of the ball - if it was made of a magnetisable material - or by building the magnets into the inside surface of the ball.

Even further the invention provides for a method for controlling the rotation of a hollow spherical ball part of a multidirectional driving ball and controlling the orientation of the rotational axis of the hollow spherical ball part to obtain a displacement between the spherical ball part and a contact surface engaging an outside surface of the spherical ball part. The method comprising the steps of:

• arranging a plurality of rotor magnets at the inside surface of the hollow spherical ball part to form a rotor of an electrical motor, and

• arranging at least two circular rows of stator magnets inside the rotor to form a stator part of the electrical motor, wherein the at least two circular rows are mutually axially displaced, and

• engaging one or more stator magnets of a first row of the at least two circular rows and engaging one or more stator magnets of a second row of the at least two circular rows magnets to drive the rotation of the hollow spherical ball part and to tilt the rotational axis of the hollow spherical ball part.

Rotating the hollow spherical ball part of a multidirectional driving ball by means of an electrical motor formed more or less integrally with the spherical ball - so at least the spherical ball forms the supporting structure of the rotor - is advantageous in that it provides for a simple and inexpensive multidirectional driving ball design.

Furthermore, by engaging stator magnets in more than one of the circular rows of stator magnets simultaneously will force the spherical ball to tilt in relation to the stator, hereby enabling that the rotational axis of the spherical ball is also tilted in relation to the contact surface against making the ball rotate against the contact surface.

In an aspect of the invention, said multidirectional driving ball is a multidirectional driving ball according to any of the preciously mentioned embodiments.

The invention further provides for a multidirectional driving ball. The multidirectional driving ball comprises a spherical ball adapted to rotate against a contact surface through a contact point on a surface of the spherical ball. The spherical ball comprises a contact plane being tangential with the spherical ball in the contact point. The multidirectional driving ball further comprises three or more support units each engaging a surface of the spherical ball, wherein at least two of the three or more support units are formed as drive units comprising drive means, wherein the drive means drives the drive units to rotate the spherical ball. The multidirectional driving ball is characterised in that the two or more drive units are adapted to rotate the spherical ball around a rotational axis which is tilted in relation to the contact plane.

In other words, if the multidirectional driving ball e.g. is used as a multidirectional drive ball of a vehicle i.e. having a contact point at the lowest point of the ball or if the multidirectional driving ball e.g. is used as a multidirectional drive ball in a horizontal conveyer, i.e. the multidirectional driving ball being flipped 180° so that it has the contact point at the highest point of the ball, the drive units are arranged to rotate the ball around a none-horizontal axis. This is advantageous in that by rotating the spherical ball around a rotational axis, which is tilted in relation to the contact plane, the contact circle on the spherical ball - i.e. the circle on the ball contacting the contact surface - will at all times be smaller than the great circle of the spherical ball whereby it can be ensured that the part of the ball surface, contacting the contact surface, is at all times different from the part of the ball surface contacting the support units or it can at least be ensured that these surface parts only rarely overlap; thus, the risk of dirt or harmful foreign objects, which are picked up by the ball surface at the contact point, is transported to the support units is greatly reduced and the functionality and the life of the support units or the spherical ball is increased accordingly.

It should be emphasised that the term "contact surface" is to be understood as the surface - external to the multidirectional driving ball - against which the ball rotates. I.e. if the multidirectional driving ball e.g. is used as a multidirectional drive ball of a vehicle e.g. a vacuuming robot, a hospital bed or the like the contact surface would be the underlying ground such as the floor and if the multidirectional driving ball e.g. is used as a multidirectional drive ball in a horizontal conveyer the contact surface would be the bottom face of a plate, a box or a similar object being transported by the conveyer. In an aspect of the invention, said two or more drive units are adapted to tilt said rotational axis of said spherical ball to a tilt angle of at least 20°, preferably at least 35° and most preferred at least 45° in relation to said contact plane.

The more the rotational axis of the spherical ball is tilted (in relation to the being parallel with the contact surface) the smaller the contact circle will get and the smaller the contact circle is, the shorter distance the ball will travel at a given rotational speed of the drive units, hereby reducing the efficiency of the ball. However, if the tilt angle is too little the risk of the area of the spherical ball surface, contacting the contact surface overlapping the area of the ball contacting the support units, is increased.

Thus, the present tilt angel ranges presents an advantageous relationship between efficiency and functionally. In an aspect of the invention, said multidirectional driving ball further comprise a control unit adapted to drive a first drive unit of said at least two drive units at a first rotational speed and a second drive unit of said at least two drive units at a second rotational speed, wherein said first rotational speed is different from said second rotational speed.

Tilting the rotational axis of the spherical ball in relation to the contact plane can be done in a number of ways but it is advantageous to do it by providing the control unit with means for controlling the rotational speed of the drive units so the one of the drive units runs faster than another drive unit in that this difference in rotational speed provides for a simple and efficient way of tilting the rotational axis of the spherical ball.

It should be noted that the term "said multidirectional driving ball further comprise a control unit" in no way is limited to the control unit physically being included in the multidirectional driving ball. This term also covers that the control unit is physically located external to the multidirectional driving ball or even that the control unit is integrated in a main control unit which also controls other functions of the apparatus in which the multidirectional driving ball is incorporated.

In an aspect of the invention, control unit further comprises means for controlling the difference between said first rotational speed and said second rotational speed.

Providing the control unit with means for controlling the difference in rotational speed between a first drive unit and a second drive unit, whether it being relative or absolute, is advantageous in that it provide for simple and inexpensive means for controlling the tilt angle of the rotational axis of the spherical ball. And controlling the tilt angle is advantageous in that it hereby is possible to control the size of the contact circle and thereby provide the multidirectional driving ball with adjustable gearing means. In an aspect of the invention, said drive units are fixed at substantially the same distance from said contact plane. Fixing the drive units at the same level is advantageous in that it is hereby possible to provide a more even and uniform support and drive of the spherical ball.

In an aspect of the invention, said three or more support units each comprises a roller, wherein said rollers have mutually fixed axis of rotation.

A roller only has one degree of freedom i.e. it can only rotate and if the axis of rotation of these rollers are mutually fixed it is possible to calculate and predict the tilt angle of the spherical ball at a given speed difference, at a given roller size difference or at a given positional difference between the two or more drive units. This is e.g. advantageous in that it can make it much simple to utilise the gearing effect of the tilted rotational axis.

In an aspect of the invention, a first drive unit roller of a first drive unit of said at least two drive units has a first drive unit roller diameter at the point of contact between said first drive unit roller and said spherical ball and a second drive unit roller of a second drive unit of said at least two drive units has a second drive unit roller diameter at the point of contact between said second drive unit roller and said spherical ball, wherein said first drive unit roller diameter is different from said second drive unit roller diameter.

A drive unit with a drive unit roller diameter different from the drive unit roller diameter of another drive unit entails that the two drive roller will have different periphery speeds at the same RPM (rotations per minute). This speed difference will entail a tilted rotational axis of the spherical ball - just as two rollers of identical diameter rotating at different speeds would - hereby providing simple means for tilting the rotational axis of the spherical ball. This embodiment is particularly advantageous if the gearing effect of controlling the tilt angle is not required.

In an aspect of the invention, a roller of said support units is arranged so that the rotational axis of said roller is tilted in relation to a roller plane perpendicular with said contact plane, intersecting the centre of said spherical ball and intersecting the contact point between said roller and said spherical ball.

If the rotational axis of the rollers of all the support units are arranged parallel with the roller plane and if they rotate at the same speed they will rotate the spherical ball around a rotational axis being tilted 90° in relation to the contact plane (for rollers of substantially the same diameter and placed at the same level). To reduce this tilt angle a speed difference has to be established but if one or more of the rollers rotate fasted than the remaining rollers they will at first only "push" at the remaining rollers.

However, by tilting the rollers rotational axis in relation to the roller plane a change in the rotational speed of one of the rollers will more easily "drag" the ball into a position where the rotational axis of the spherical ball is tilted.

Furthermore, if the multidirectional driving ball is used in a configuration in which it will have a preferred direction of motion e.g. in a conveyer, a vacuuming robot, a wheel chair etc. the angle of the rollers rotational axis can be arranged so that angle between the contact circle - defined by the rollers contact with the ball surface - will be more perpendicular to the rollers rotational axis when the rotational axis of the spherical ball is tilted to the desired angle and a state of equilibrium regarding load is substantially established. Thus, the transversal motion between the ball and the rollers can be significantly reduced when the multidirectional driving ball is travelling in a preferred direction. In an aspect of the invention, a first drive unit of said at least two drive units is fixed at a first distance from said contact plane and a second drive unit of said at least two drive units is fixed at a second distance from said contact plane, wherein said first distance is different from said second distance.

If two identical drive rollers, rotating at the same speed, are placed at different levels, the diameter of their contact circles will be different hereby providing simple and inexpensive means for tilting the rotational axis of the spherical ball. This embodiment is also particularly advantageous if the gearing effect of controlling the tilt angle is not required.

In an aspect of the invention, a first surface area and a second surface area of said spherical ball has mutually different properties regarding hardness and/or roughness. Arranging the drive units so they rotate the spherical ball around a rotational axis, which is none-parallel with the contact plane, enables that it is possible to maintain the part of the ball surface getting in contact with the contact surface different from the part of the ball surface getting in contact with the support units at all times, whereby the different surface parts of the ball can be optimised for their specific purpose. E.g. the part of the ball surface contacting the contact surface could e.g. be made of a hard and durable material and the part of the ball surface contacting the support units could be made of a material ensuring high friction between the drive units an the ball surface or the ball surfaces could in other ways be optimised to the specific use of the multidirectional driving ball.

In an aspect of the invention, said three or more support units are all formed as drive units comprising drive means.

Providing the multidirectional driving ball with at least three drive units is advantageous in that it enables a more even distribution of the drive loads and because it makes it much easier to control the actual tilt angle if the multidirectional driving ball comprises three drive units having rotational speeds which can be individually controlled. In an aspect of the invention, said three or more support units are distributed evenly around an axis perpendicular with said contact plane and going through the centre of said spherical ball.

Distributing the support units evenly is advantageous in that it provides for a more even load distribution and a more secure fixation of the spherical ball.

Even further the invention provides for a method for rotating a spherical ball of a multidirectional driving ball to obtain a displacement between the spherical ball and a contact surface engaging a surface of the spherical ball in a contact point. The method comprises the steps of:

• arranging two or more drive units comprising drive means so that they drive a rotation of the spherical ball, and · rotating the drive means of a first drive unit of the two or more drive units at a first rotational speed and rotating the drive means of a second drive unit of the two or more drive units at a second rotational speed, wherein the first rotational speed is different from the second rotational speed to tilt the rotational axis of the spherical ball in relation to a contact plane being tangential with the spherical ball in a contact point with the contact surface.

Rotating the spherical ball around a "none-horizontal" rotational axis is advantageous in that risk of the ball surface dragging dirt and unwanted foreign objects into the support units is significantly reduced, which furthermore is particularly advantageous in relation to multidirectional driving balls in that some of the two or more drive units will inherently see a transversal motion which will wear the drive units and/or the ball and even more when dirt, grains of sand or other is introduced in the frictional engagement between the drive units and the ball surface. In an aspect of the invention, the relative difference between said first rotational speed and said second rotational speed is adjusted to control the tilt angle of the rotational axis of said spherical ball in relation said contact plane.

Controlling the speed difference is advantageous in that it hereby is possible to provide the multidirectional driving ball with a gearing which could reduce or eliminate the need for gearing a the individual drive units and it provides the multidirectional driving balls with an increased speed range.

In an aspect of the invention, said multidirectional driving ball is a multidirectional driving ball according to any of the previously mentioned embodiments of a multidirectional driving ball.

Even further the invention provides for a method for adjusting the gearing of the » rotation of two or more drive units, driving a spherical ball of a multidirectional driving ball, in relation to a displacement of said multidirectional driving ball on a contact surface contacting said spherical ball, said method comprising the steps of:

• rotating the drive means of a first drive unit of said two or more drive units at a first rotational speed and rotating the drive means of a second drive unit of said two or more drive units at a second rotational speed, wherein said first rotational speed is different from said second rotational speed to tilt the rotational axis of said spherical ball in relation to a contact plane being tangential with said spherical ball in a contact point with said contact surface, and • changing the relative difference between said first rotational speed and said second rotational speed to adjust the tilt angle of the rotational axis of said spherical ball in relation said contact plane. The invention provides for a multidirectional driving ball comprising a hollow spherical ball part including an inside surface and an outside surface. The multidirectional driving ball is characterised in that the multidirectional driving ball further comprises three or more support units each engaging the inside surface of the spherical ball, wherein at least two of the three or more support units are drive units comprising drive means, wherein the drive means enables that the drive units rotate the spherical ball.

Placing the support units inside the spherical ball part is advantageous in that the units are well protected, in that the risk of the surface part of the ball contacting the contact surface at all times is different from the surface part of the ball contacting the support units and in that it enables an advantageous design of the multidirectional driving ball.

In an aspect of the invention, said two or more drive units are adapted to rotate said spherical ball part around a rotational axis which is tilted in relation to a contact plane, wherein said contact plane is tangential with said spherical ball part in a contact point between said spherical ball part and a contact surface against which said spherical ball part rotates. Providing the multidirectional driving ball with three or more support units - of which at least two are driven - is advantageous it make it possible to rotate the spherical ball part around a rotational axis, which is tilted in relation to a contact surface, against which the spherical ball part rotates, whereby only a part of the ball outside surface is in contact with the contact surface. This enables that the spherical ball part can be formed as a bowl i.e. it can comprise a none-spherical surface part enabling access to the inside of the hollow spherical ball part and that the support units can be arranged inside this bowl.

In an aspect of the invention, an inside surface area and an outside surface area of said spherical ball part has mutually different properties regarding hardness and/or roughness.

This is advantageous in that the outside surface hereby can be optimised to the contact with the given contact surface and the inside surface can be optimised in relation to the support units.

The invention further provides for a method for rotating a hollow spherical ball part of a multidirectional driving ball to obtain a displacement between the spherical ball part and a contact surface engaging the outside surface of the spherical ball part in a contact point. The method comprises the steps of:

• arranging two or more drive units comprising drive means so that they drive a rotation of said spherical ball part inside said hollow spherical ball part, and · rotating the drive means of a first drive unit of said two or more drive units at a first rotational speed and rotating the drive means of a second drive unit of said two or more drive units at a second rotational speed, wherein said first rotational speed is different from said second rotational speed to tilt the rotational axis of said spherical ball part in relation to a contact plane being tangential with said spherical ball part in said contact point.

Rotating the spherical ball around a "none-horizontal" rotational axis is advantageous in that risk of the ball surface dragging dirt and unwanted foreign objects into the support units is eliminated and arranging the support units inside the hollow spherical ball part is advantageous in that the units are well protected, in that the risk of the surface part of the ball contacting the contact surface at all times is different from the surface part of the ball contacting the support units and in that it enables an advantageous design of the multidirectional driving ball

Figures

The invention will be described in the following with reference to the figures in which illustrates a simplified embodiment of a multidirectional driving ball having a tilt angle of 90°, as seen from the side, illustrates a simplified embodiment of a multidirectional driving ball having a tilt angle of 80°, as seen from the side. illustrates a simplified embodiment of a multidirectional driving ball having a tilt angle of 70°, as seen from the side, fig. 4 illustrates a simplified embodiment of a multidirectional driving ball having a tilt angle of 60°, as seen from the side, fig. 5 illustrates a simplified embodiment of a multidirectional driving ball comprising three vertically displaced drive units, as seen from the side, fig. 6 illustrates a simplified embodiment of a multidirectional driving ball comprising three horizontally arranged drive units, as seen from the side, fig. 7 illustrates a simplified embodiment of a multidirectional driving ball comprising three vertically arranged drive units, as seen from the side, fig. 8 illustrates a simplified embodiment of a multidirectional driving ball used in a conveyer, as seen from the side, fig. 9 illustrates a simplified embodiment of a multidirectional driving ball comprising two vertically arranged drive units, as seen from the side, fig. 10 illustrates a simplified embodiment of a multidirectional driving ball comprising three drive units having different roller diameter, as seen from the side, fig. 1 1 illustrates a simplified embodiment of a multidirectional driving ball comprising three drive units arranged inside the hollow spherical ball, as seen in perspective, fig. 12 illustrates a cross section through a spherical ball comprising three drive units, as seen from the side, fig. 13 illustrates the same embodiment shown in fig. 12, as seen in perspective, illustrates a cross section through a spherical ball comprising two drive units, as seen from the side, illustrates a cross section through a spherical ball comprising three drive units arranged at different levels, as seen from the side, illustrates a cross section through a horizontal spherical ball comprising a rotor, as seen from the side, illustrates the same embodiment shown in fig. 16 with a tilted rotational axis, as seen from the side, illustrates a multidirectional driving ball with rotor and stator arranged inside the spherical ball, as seen in perspective, illustrates cross section through a multidirectional driving ball comprising a ball cover, as seen from the side, and fig. 20 illustrates cross section through a multidirectional driving ball comprising an inflatable tyre, as seen from the side.

Detailed description of the invention

Fig. 1 illustrates a simplified embodiment of a multidirectional driving ball 1 having a tilt angle a of 90°, as seen from the side.

In this embodiment of the invention the multidirectional driving ball 1 is arranged to rotate against a substantially flat contact surface 3 - such as a floor - beneath the multidirectional driving ball 1. This orientation of the multidirectional driving ball 1 is appropriate e.g. if the driving ball 1 is implemented in a fork lift, a pallet lifter, a hospital bed, a wheel chair, household robots, toys or similar equipment or vehicles where the multidirectional driving ball 1 is used for propelling a movement of the equipment or vehicle - in which it is incorporated - over the ground surface it contacts.

However, the advantages and functions of the multidirectional driving ball 1 are in no way limited to a specific orientation. As disclosed later the multidirectional driving ball 1 can just as well be used against a surface above the multidirectional driving ball 1 e.g. in a conveyer and systems, in which the multidirectional driving ball 1 is arranged to rotate against a vertical surface or a surface of any other orientation, is just as feasible. In this embodiment of the invention the multidirectional driving ball 1 comprises three support units 5 but in another embodiment of the invention the multidirectional driving ball 1 could comprise another number of support units 5 such as four, five, six or more. However, to properly stabilise the spherical ball 2 it need to be supported by at least three support units 5.

In this embodiment of the invention all the support units 5 are established as drive units 6 in that the rollers 1 1 of each of the support units 5 are connected to drive means (not shown in figs. 1-4) driving a rotation of the rollers 1 1 which by means of friction between the rollers 11 and the spherical ball 2 will lead to rotation of the spherical ball 2.

In this embodiment of the invention the drive units 6 are arranged in the same distance from the contact surface 3 and the drive units 6 are all identically. Furthermore, the drive units 6 all rotate at the same speed making the spherical ball 2 rotate around a rotational axis 8 being perpendicular to the contact surface 3 and contact plane i.e. the tilt angle a is 90° and in this embodiment the spherical ball 2 therefore rotates around a vertical axis.

The contact plane is defined as the plane being tangential with the outer surface 19 of the spherical ball 2 in the spherical ball's contact point 4 with the contact surface 3. For a substantially flat contact surface 3 the contact plane with be coinciding with the contact surface.

When the tilt angle a of the spherical ball's rotational axis 8 is 90° the contact circles 16 of the support units 5 will coincide and the spherical ball 2 will only spin in the same place.

It should be emphasized that the explanations regarding how the tilted rotational axis 8 is obtained as disclosed in relations with figs. 1-5 applies mutatis mutandis for multidirectional driving balls 1 having the support units 5 placed inside the ball 1 as disclosed in figs. 1 1-15 and to some degree also the embodiments disclosed in figs. 16-20.

Fig. 2 illustrates a simplified embodiment of a multidirectional driving ball 1 having a tilt angle a of 80°, as seen from the side.

In this embodiment a difference is established between the rotational speeds of the three drive units 6 whereby the rotational axis 8 of the spherical ball 2 is tilted to 80°. In principle, as soon as the rotational axis 8 of the spherical ball 2 differs from 90° the ball 2 will start moving in relation to the contact surface 3 in that the rotation of the ball 2 will form an endless circle of contact points between the ball surface 19 and the contact surface 3 illustrated by the contact circle 17. The diameter of the contact circle 17 will change in accordance with the tilt angle a of the rotational axis 8 of the spherical ball 2 hereby providing the multidirectional driving ball 1 with a gearing which can be adjusted stepless by adjusting the difference between the rotational speeds of the drive units 6.

In this embodiment the drive units are shown without their drive means which preferably is electrical motors.

Most common electrical motors suitable for use in relation with the drive units 6 of a multidirectional driving ball 1 usually have a specific speed range at which they produce the most torque in relation to the consumed power. At a given desired travel speed of the multidirectional driving ball 1 in relation to a contact surface 3, it is therefore possible to run the electrical motors at or close to this torque peak by carefully controlling the individual rotational speed of the drive units 6 to establish the right relationship between the actual speeds of the motors and the mutual differences in rotational speed to provide for the least power consuming operation of the multidirectional driving ball 1 no matter the desired speed.

Another great advantage of this gearing effect is that the speed range of the multidirectional driving ball 1 is greatly increased hereby enabling implementation in more connections and that the nominal size of the motors can be reduced, hereby making the motors less expensive and enabling a more compact design of the multidirectional driving ball 1.

A further advantage of this multidirectional driving ball 1 is that when the dri ve units 6 are stopped and the spherical ball 2 is therefore not rotating the spherical ball 2 is locked for rotation in practically any direction. Thus, if the multidirectional driving ball 1 is build into a vehicle or a conveyer the multidirectional driving ball 1 inherently comprises a brake and no further brakes are necessary.

Fig. 3 illustrates a simplified embodiment of a multidirectional driving ball 1 having a tilt angle a of 70°, as seen from the side. As long as the tilt angle a of the rotational axis 8 of the spherical ball 2 is maintained between 90° and approximately 22.5° the contact circles 16 between the support units 5 and the ball surface will never overlap the contact circle 17 between the contact surface 3 and the ball surface 3 - given that the support units 5 are arranged in an angle of 45° in relation to a plane through the centre of the ball 2 and parallel with the contact plane. Thus, the risk of dirt or harmful foreign objects being picked up by the ball surface at the contact point 4 with the contact surface 3 and transported to the support units 5 is thereby completely eliminated and if the tilt angle a is further reduced the risk of transporting e.g. grains of sand into support units 5 is greatly reduced in that the contact circle 17 between the contact surface 3 and the ball surface 3 will only overlap the contact circles 16 between the support units 5 and the ball surface briefly when the multidirectional driving ball 1 changes direction. Fig. 4 illustrates a simplified embodiment of a multidirectional driving ball 1 having a tilt angle a of 60°, as seen from the side.

Comparing this figure with figure 2 clarifies the gearing effect, in that tilting the rotational axis 8 of the spherical ball 2 20°, from 80° in fig. 2 to 60° in fig. 4, makes the ^" diameter of the contact circle 17 between the contact surface 3 and the ball surface about four times bigger. Thus, merely by adjusting the mutual rotational speeds of the drive units 6 it is possible to make the multidirectional driving ball 1 run four times faster with increasing the top speed of any of the drive units 6. Because the contact circles 16 between the support units 5 and the ball surface never or only rarely overlaps the contact circle 17 between the contact surface 3 and the ball surface 3 the spherical ball 2 is in this embodiment of the invention provided with a first surface area 14 which in this embodiment is an upper hemisphere of the ball 2 and a second surface area 15 which in this embodiment is a lower hemisphere of the ball 2. In this embodiment the first surface area 14 is formed as a hard e.g. metal surface to ensure the ball durability whereas the second surface area 15 is formed as a relatively soft rubber surface to reduce noise emission and dampen vibrations. However in another embodiment the properties of the two surface areas 14, 15 could be formed differently e.g. to adapt to the specific use of the multidirectional driving ball 1.

If the ball 2 is provided with different surface areas 14,15 it could also be advantageous to be able to track the exact orientation of the spherical ball 2. The multidirectional driving ball 1 could therefore also be provide with one or more sensors detecting this orientation of the spherical ball 2 and the control unit (not shown) could comprise means for calibrating the orientation of the ball 2.

Fig. 5 illustrates a simplified embodiment of a multidirectional driving ball 1 comprising three vertically displaced drive units 6, as seen from the side.

In this embodiment of the invention as well as the embodiments disclosed in all the other figures the axis of rotation 10 of rollers 11 of all the support units 5 are fixed in relation to each other. However, in relation to the embodiments disclosed in figs. 1-4 the axis of rotation 10 of rollers 1 1 of all the support units 5 are in this embodiment tilted to a tilt angle β of about 35° in relation to a to a plane perpendicular with the contact plane, intersecting the centre of the spherical ball 2 and intersecting the contact point between said roller 11 and surface of the spherical ball 2.

Fig. 6 illustrates a simplified embodiment of a multidirectional driving ball 1 comprising three horizontally arranged drive units 6, as seen from the side.

In this embodiment of the invention the drive units 6 comprises drive means 7 in the form of electrical motors arranged with their rotational axis substantially parallel with the contact plane and thereby the contact surface 3. This particular design provides the multidirectional driving ball 1 with a very small built-in height. To ensure proper contact between the rollers 1 1 and the ball surface the rollers are in this embodiment cone shaped. The gradient of the cone could advantageously be dependent on the drive unit's 6 angle in relation to the contact plane and thereby the contact surface 3.

Fig. 7 illustrates a simplified embodiment of a multidirectional driving ball 1 comprising three vertically arranged drive units 6, as seen from the side. By arranging the drive units 6 so that their axes of rotation are substantially perpendicular with the contact surface 3 a very narrow multidirectional driving ball 1 design is ensured.

Fig. 8 illustrates a simplified embodiment of a multidirectional driving ball 1 used in a conveyer, as seen from the side.

In relation to the embodiments shown in the other figures the multidirectional driving ball 1 is in this embodiment flipped upside down so that the contact point 4 of the spherical ball 2 is at the top of the ball 2 which extents up through a top plate 33 of the conveyer to propel a displaceable object 32 placed on the conveyer.

In this embodiment the drive units 5 are arranged in a crossed configuration and the drive means 7 of all the drive units 6 are connected to a control unit 9. The control unit 9 at least comprises means for individually controlling the rotational speed of the drive means so that a desired travel speed of the displaceable object 32 on the conveyer can be obtained by the control unit 9 defining the appropriate speed difference between the drive units 6 and feeding the appropriate speed control signal or similar to the drive means 7. In another embodiment of the invention the control unit 9 could also or instead comprise means for controlling the multidirectional driving ball 1 base on a torque measurement. When knowing the roller 1 1 diameter the torque is substantially directly proportional with the current.

Fig. 9 illustrates a simplified embodiment of a multidirectional driving ball 1 comprising two vertically arranged drive units 6, as seen from the side.

In this embodiment of the invention one of the support units 5 are formed as a non- driven roller 1 1 while the other two support units 5 are formed as drive units 6.

By forming the non-driven support units 5 as a roller 1 1 having only one degree of freedom - i.e. it can only rotate - it is possible to tilt the rotational axis 8 of the spherical ball 2 by establishing difference in the rotational speed between the drive units 6 even though there is only two of them.

However in another embodiment the rollers 11 could be mounted on some sort of rotary joint allowing that the orientation of the rotational axis 10 of the roller 1 1 could be adjusted by force or freely.

Fig. 10 illustrates a simplified embodiment of a multidirectional driving ball 1 comprising three drive units 6 having different roller diameter, as seen from the side.

In this embodiment of the invention the multidirectional driving ball 1 comprises a first drive unit roller 12 having a first drive unit roller diameter and a second drive unit roller 13 having a second drive unit roller diameter, and the first drive unit roller diameter is larger than the second drive unit roller diameter so that when the rollers 12,13 rotate at the same rotational speed they will describe contact circles 16 of different diameters on the ball surface, thus tilting the rotational axis 8 of the spherical ball 2. Fig. 1 1 illustrates a simplified embodiment of a multidirectional driving ball 1 comprising three drive units 6 arranged inside the hollow spherical ball 2, as seen in perspective.

In this embodiment of the invention the spherical ball 2 is formed as a hollow bowl and the support units 5, which in this case are three drive units 6, are placed inside the ball 2 so that the rollers 11 of the drive units 6 contacts the inside surface 18 of the ball 2.

To ensure that the control unit (not shown) at all time or at least occasionally knows the exact orientation of the spherical ball 2 - e.g. to ensure that support units 5 at all times runs against the inside surface 18 of the ball - the multidirectional driving ball 1 could further be provided with one or more sensors detecting this orientation of the spherical ball i.e. to detect the actual position of the opening in the "bowl".

Fig. 12 illustrates a cross section through a spherical ball 2 comprising three drive units 6, as seen from the side. Fig. 13 illustrates the same embodiment shown in fig. 12, as seen in perspective.

Fig. 14 illustrates a cross section through a spherical ball 2 comprising two drive units 6, as seen from the side. Fig. 15 illustrates a cross section through a spherical ball 2 comprising three drive units 6 arranged at different levels, as seen from the side.

Fig. 16 illustrates a cross section through a horizontal spherical ball 1 comprising a rotor 21, as seen from the side. Only the front half of the ball 2 is removed to provide a better look at the inside of the multidirectional driving ball 1. In this embodiment of the invention a number of rotor magnets 20 is attached to the inside surface 18 of ball 2 to form a rotor of an electrical motor 22. Preferably the rotor magnets 20 are permanent magnets but in principle the rotor magnets 20 could be electro magnets.

The rotor magnets 20 are arranged in a single circular row inside the ball 2 but in another embodiment the rotor magnets could be arranged in two, three or more circular rows being mutually displaced in the axial direction of the rotor 21 on the inside surface 18 of the ball 2.

Inside the rotor 21 is arranged a stator 23 of the electrical motor 22 in that a number of stator magnets 24 are arranged in two circular rows 25 being mutually displaced in the axial direction of the stator 23. In another embodiment the stator could comprise three, four or more circular rows 25.

In this embodiment the spherical ball 2 does not rotate and the tilt angle a of the spherical ball's rotational axis is therefore 90°. To prevent the ball from rotating when this is not desired the multidirectional driving ball 1 could advantageously further comprise a dedicated brake. In one embodiment of the invention this brake could be designed as one or more lock pins engaging between the stator part and the spherical ball and the lock pins could either be driven by the ball rotation or by a dedicated drive source such as one or more solenoids. The force of the motor could e.g. be used to fix the lock pins during standstill by creating a counter force.

Fig. 17 illustrates the same embodiment shown in fig. 16 with a tilted rotational axis 8, as seen from the side. In this embodiment of the invention the stator magnets 23 are electro magnets and by activating the electro magnets in the right order at the right frequency it is possible to drive a rotation of the rotor 21 in relation the stator 23 as it is well known from electrical motors known in the art. However, by engaging some of the electro magnets in both of the circular rows 25 of stator magnets 24 simultaneously or in the right order it is possible to also control the tilt angle a between the stator 23 and the rotor 21 and thereby between the spherical ball 2 and the contact surface 3 to enable that the spherical ball 2 starts rolling against the contact surface 3. To ensure that the control unit (not shown) at all time or at least occasionally knows the exact orientation of the spherical ball 2 - e.g. to ensure a desired position of the rotor 21 in relation to the stator 23 at standstill - the multidirectional driving ball 1 could further be provided with one or more sensors detecting this orientation of the spherical ball i.e. to detect the actual position of the opening in the "bowl".

Fig. 18 illustrates a multidirectional driving ball 1 with rotor 21 and stator 23 arranged inside the spherical ball 2, as seen in perspective.

Fig. 19 illustrates cross section through a multidirectional driving ball 1 comprising a ball cover 34, as seen from the side.

In this embodiment of the invention the rotor 21 is connected to the stator 23 by means of a ball joint 26 enabling that the tilt angle a between the stator 23 and the rotor 21 and thereby between the spherical ball 2 and the contact surface 3 can be changed but at the same time ensuring that the air gap between the rotor magnets 20 and the stator magnets 24 are maintained substantially constant at all times.

In another embodiment of the invention the rotor 21 could be connected to the stator 23 by means of some kind of arrangement at least comprising a universal joint, a universal coupling, a U joint, a Cardan joint, a Hardy-Spicer joint, a Hooke's joint or any other kind of joint or coupling substantially allowing the spherical ball 2 to 'bend' in any direction while still allowing rotary motion hereby allowing the tilt angle a between the stator 23 and the rotor 21 to be changed but at the same time ensuring that the air gap between the rotor magnets 20 and the stator magnets 24 are maintained substantially constant at all times.

To ensure a substantially frictionless rotation between the stator 23 and the rotor 21 the spherical ball 2 further comprises a bearing housing 31 in which a couple of bearings 29 are provided to ensure free rotation towards the shaft part 27 of the ball joint 26.

To protect the electronic and mechanical equipment inside the ball 2 the top opening of the ball 2 is provided with a flexible cover 30 e.g. making the multidirectional driving ball 1 substantially wash and water tight.

And to further protect the flexible cover 30 and electronic and mechanical equipment inside the ball 2 from external mechanical impact and other the multidirectional driving ball 1 is further provided with a substantially rigid ball cover 34. Fig. 20 illustrates cross section through a multidirectional driving ball 1 comprising an inflatable tyre 28, as seen from the side.

When the ball drive i.e. the electrical motor 22 is placed inside the spherical ball 2 the outside surface 19 of the ball 20 can be optimized to the specific use of the multidirectional driving ball 1.

In this case the specific use requires that the noise emission and vibrations are kept at a minimum and for that reason the outside surface 19 of the ball 2 is enclosed in an inflatable tyre 28. The inflatable tyre 28 surface will also ensure excellent traction towards most any contact surface.

The invention has been exemplified above with reference to specific examples of designs and embodiments of multidirectional driving balls 1 , support units 5, drive units 6 etc. However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims.

List

1. Multidirectional driving ball

2. Spherical ball

3. Contact surface

4. Contact point

5. Support unit

6. Drive unit

7. Drive means

8. Rotational axis of spherical ball

9. Control unit

10. Axis of rotation of roller

1 1. Roller

12. First drive unit roller

13. Second drive unit roller

14. . First surface area

15. Second surface area

16. Contact circle of support unit

17. Contact circle of spherical ball

18. Inside surface of spherical ball

19. Outside surface of spherical ball

20. Rotor magnet

21. Rotor

22. Electrical motor

23. Stator

24. Stator magnet

25. Circular row of stator magnets

26. Ball joint

27. Shaft part

28. Inflatable tyre 29. Bearing

30. Flexible cover

31 Bearing housing

32. Displaceable object

33. Top plate of conveyer

34. Ball cover

Dl . First distance from contact plane

D2. Second distance from contact plane

D3. Third distance from contact plane

D4. Outside diameter of rotor

D5. Inside diameter of spherical ball a. Tilt angle of spherical ball β· Tilt angle of roller