IT202100032816A1 - Improved electrospindle - Google Patents

Description

IMPROVED ELECTROSPINDLE

The present invention concerns an improved electrospindle.

Field of invention

In particular, the present invention concerns the structure of said electrospindle designed to receive a plurality of of ventilation devices to cool the electric motor of said electrospindle.

Known technique

As ? known, a machine tool includes a machining head equipped with one or more? electrospindles.

An electrospindle includes a shaft having a longitudinal axis and an electric motor for rotating said shaft around said longitudinal axis.

Furthermore, an electrospindle has a first end portion? on which ? a respective tool and a second end portion can be positioned, opposite to said first end portion.

For machining a workpiece, the first end portion? can? be coupled directly to the tool or equipped with a support/tool holder that can be coupled with the tool.

The tool? chosen based on the work to be performed. For example, if it is necessary to make a hole, the tool can be a drill bit.

When is an electrospindle? In use, the electric motor causes the rotation of the shaft and the rotation of the shaft causes the rotation of the tool.

The temperature of the electric motor increases while processing a workpiece.

In particular, the temperature increases significantly when the workpiece is made with a hard material, such as marble, glass, stone, etc.

Consequentially ? It is advisable for the electric motor of the electrospindle to be cooled.

To this end, the electrospindle can be equipped with a unit? cooling or, alternatively, a ventilation device.

A first example of a known type electrospindle includes a unit cooling.

This unit? cooler includes a pumping device for pumping a liquid (such as water) into one or more? conducted inside the electrospindle.

A first disadvantage? given by the fact that ? Is it necessary to mount a unit? cooling inside the electrospindle, with the resulting times and costs.

A second disadvantage? given by the volume occupied by the unit? cooling positioned inside the electrospindle.

Therefore, liquid cooling of the electrospindle involves the presence of additional components to be inserted inside the machine tool.

A third disadvantage? given by necessity? to submit the unit? cooling to periodic maintenance operations, for example to control the temperature of the liquid.

A second example of a known type electrospindle includes a ventilation device.

Said ventilation device includes a single fan which? keyed onto the electrospindle shaft.

A disadvantage? given by the fact that the speed? rotation of the fan depends on the speed? of rotation of the shaft.

In other words, the speed? of fan rotation not ? independent of speed? of rotation of the shaft.

Consequently, when the electrospindle shaft does not rotate since? the electric motor? off, it would be necessary to continue to cool the electric motor because? the latter ? still hot and instead the electric motor can't? to have a cold. In particular, the most used and burdensome are those with low rpm. In such processes it would be necessary to cool the electric motor of the electrospindle, but, since? the fan runs at a low speed, the electric motor is not cooled.

A third example of a known type electrospindle includes a ventilation device.

As for the second example of a known type electrospindle, said ventilation device includes a single fan.

However, differently from the ventilation device present in the second example of an electrospindle of the type described above (in which the fan is keyed onto the shaft of the electrospindle), in said third example of an electrospindle of a known type, the fan is positioned on the second end portion? of the electrospindle.

A first disadvantage? due to the fact that said fan ? sized to guarantee cooling of the electric spindle motor in the worst situation, i.e. considering the electrospindle in use when the piece to be machined? made with a hard material (such as marble, glass, stone, etc.).

Furthermore, the ventilation device is arranged at least partially inside the electrospindle, along an axis parallel to the longitudinal axis of the electrospindle shaft, and the fan is positioned on an end wall? of the end portion? of the electrospindle.

Consequently, a second disadvantage? given by the fact that the volume occupied by said ventilation device inside the electrospindle, in axial terms, is significant because the ventilation device? designed to cool the electrospindle in the worst situation.

A further disadvantage due to the position of said fan? the difficulty? by an operator to access one or more? components of the electrospindle in the event of a malfunction/failure or maintenance.

For example for an operator? difficult to access the shaft bearings which need to be lubricated periodically.

Purpose of the invention

Purpose of the present invention? overcome said disadvantages by providing an improved electrospindle, having a simple structure and a low production cost.

Further purpose? provide an electrospindle sized to occupy less space than a known type electrospindle equipped with a ventilation device comprising a single fan.

Object of the invention

Therefore, the specific object of the present invention is an electrospindle comprising: a casing comprising a first end wall and a second end wall, opposite to said first end wall, a shaft having a longitudinal axis, arranged at least partially inside said casing, an electric motor for rotating said shaft around said longitudinal axis, arranged inside. inside of said casing, a plurality? of ducts, obtained in said casing, in which each duct of said plurality? of ducts has a respective first end? and a respective second end, opposite to said first end, in which each first end? ? arranged on said first end wall? of said casing, at least one ventilation device for at least one duct of said plurality? of ducts, what? that a respective jet of air is emitted in said at least one duct, in which each ventilation device is arranged on said second end wall? of said casing.

Advantageously according to the invention, said electrospindle can include a respective ventilation device for each duct, so? that a respective jet of air is emitted into a respective duct.

Again according to the invention, each duct of said plurality? of ducts can? have a respective axis, parallel to the longitudinal axis of the shaft, in which each ventilation device is? arranged along the axis of a respective duct.

Still according to the invention, said casing can have a first length and each duct can? have a second length equal to said first length, in which the second end? of each duct can? be placed on said second end wall? of said casing, and each ventilation device can? be positioned on a respective second extremity? of each duct.

Conveniently according to the invention, said casing can have a first length and each duct can? have a second length smaller than said first length and the second extremity? of each duct can? be arranged on the same plane within said casing.

Still according to the invention, said casing can comprising a first part and a second part, wherein said first part and said second part are removably coupled to each other, wherein said first part includes said first end wall? of said casing and said second part includes said second end wall? of said casing.

Advantageously according to the invention, the second length of each duct can be equal to the length of said first part of said casing.

Again according to the invention, said ducts can be four and said ventilation devices can be four.

Conveniently according to the invention, said second end wall? can? have a quadrangular shape, in which the second ends? of said ducts are arranged at the vertices of said quadrangular shape.

Again according to the invention, said quadrangular shape can be a rectangle or a square.

Still according to the invention, said tree can include inside a duct for the passage of a liquid, and in which said electrospindle can? comprise includes a rotary joint, arranged inside said casing, in which said rotary joint can? include an additional duct inside it and? connected to said shaft in such a way that said further duct is aligned and coaxial with said duct for the passage of said liquid.

Advantageously according to the invention, each duct can have a respective internal surface equipped with a respective plurality? of protrusions.

Still according to the invention, said electrospindle can comprising a respective sensor disposed on each ventilation device and configured to detect a malfunction of said ventilation device.

The subject of the invention is also a machining head including said electrospindle.

The subject of the invention is also a machine tool for processing pieces, comprising: a base, a work surface to support at least one piece, in which said work surface is? placed on said base, and a unit? of processing to work said piece, in which said unit? of processing includes at least said processing head.

List of attached figures

Will this invention come? now described by way of illustration but not by way of limitation, according to its preferred embodiments, with particular reference to the attached figures, in which:

figure 1? a side perspective view of a first embodiment of an electrospindle, according to the present invention;

figure 2? a front perspective view of the electrospindle in figure 1;

figure 3? a cross-sectional view of the electrospindle to show the electric motor including a stator and a rotor, as well as? a shaft arranged inside the rotor and integral with said rotor;

figure 4 shows the electrospindle of figure 1, in which a plurality? of components? was removed to show only a plurality? of ducts arranged inside the casing, each of which extends along the entire length of the casing and is connected to a respective ventilation device;

figure 5 shows a variant of the electrospindle of figure 4, in which each duct extends for a length shorter than the length of the casing;

figure 6? a rear perspective view of a second embodiment of the electrospindle, according to the invention;

figure 7? a rear view of the electrospindle in figure 6.

In the various figures the similar parts will be indicated with the same numerical references.

Detailed description of the invention

With reference to figures 1-4, a first embodiment of an electrospindle is described.

In the first embodiment described, a tool U ? mounted on said electrospindle.

This electrospindle includes:

- a casing 1, comprising a first end wall? 1A and a second end wall? 1B, opposite to said first end wall? 1A,

- a shaft 3 having a longitudinal axis A, arranged at least partially (i.e. partially or totally) inside said casing 1,

- an electric motor 2 to rotate said shaft 3 around said longitudinal axis A, arranged inside said casing 1, and

- a plurality? of ducts C1,C2,?CN arranged in said casing 1, in which each duct C1,C2,?CN of said plurality? of ducts C1,C2,?CN has a respective axis A1,A2,?AN, parallel to the longitudinal axis A of the shaft 3, as well as? does it have a respective first end? and a respective second end, opposite to said first end, in which said first end? ? arranged on said first end wall? 1A of said casing 1.

Furthermore, said electrospindle includes a plurality? of ventilation devices F1,F2,?FN to emit a respective jet of air.

In particular, said electrospindle includes a respective ventilation device F1,F2,?FN for each duct C1,C2,?CN.

Each ventilation device F1,F2,?FN ? placed on the second end wall? 1B of said casing 1, along the axis A1,A2,?AN, of a respective duct C1,C2,?CN or substantially the axis A1,A2,?AN, of a respective duct C1,C2,?CN, in such a way that the jet of air emitted by each ventilation device F1,F2,?FN enters a respective duct C1,C2,?CN.

In another embodiment of the present invention, said electrospindle can understand a plurality? of ventilation devices F1,F2,?FN for each duct C1,C2,?CN.

For example, said electrospindle can? include two or three ventilation devices F1,F2,?FN for each duct C1,C2,?CN.

In a further embodiment of the present invention, said electrospindle can comprise a respective ventilation device F1,F2,?FN for each duct of a plurality? of ducts C1,C2,?CN and no ventilation device F1,F2,?FN for further plurality? of ducts C1,C2,?CN.

For example, said electrospindle can? include respective ventilation devices F1,F2,?FN for some ducts C1,C2,?CN while no ventilation device for further ducts C1,C2,?CN. With particular reference to the casing 1, said casing 1 has a cavity? in which ? the electric motor 2 is housed.

With particular reference to the electric motor 2, said electric motor 2 includes a stator 21 and a rotor 22.

The rotor 22 ? placed inside said stator 21.

In particular, the stator 21 has a first surface or external surface 21A and a second surface or internal surface 21B.

The external surface 21A of the stator 21 contacts a portion of the casing 1.

In particular, the rotor 22 also has a first surface or external surface 22A and a second surface or internal surface 22B.

The internal surface 22B of the rotor 22 contacts at least partially the shaft 3.

With particular reference to tree 3, called tree 3? arranged at least partially inside the electric motor 2.

In particular, tree 3 is arranged inside the rotor 22 of the electric motor 2.

Tree 3 ? integral with the electric motor 2 (in particular with the rotor 22 of the electric motor 2), so? that the rotation of said electric motor 2 causes the rotation of said shaft 3.

The rotation of said shaft 3 causes the rotation of the tool U mounted on the electrospindle.

With particular reference to the C1,C2,?CN ducts, the first end? of each duct C1,C2,?CN ? one end? free, i.e. one end? facing the external environment.

In other words, each duct C1,C2,?CN has a respective opening towards the external environment.

There? allows a passage of a quantity? of air from the external environment in each duct C1, C2,?CN present in said casing 1.

With reference to the ventilation devices F1,F2,?FN, each ventilation device F1,F2,?FN includes at least one respective fan.

When is the electrospindle ? in use, the electric motor 2 overheats, particularly if the workpiece is ? a panel made of a hard material, such as marble, glass or stone.

When is the electrospindle ? in use, the heat expands from the electric motor 2 inside the casing 1.

In particular, the heat expands from the rotor 22 to the stator 21 and from the stator 21 inside the casing 1 up to the ducts C1,C2,?CN.

When the ventilation devices F1,F2,?FN are in use, a respective jet of air? directed in each of said ducts C1,C2,?CN to obtain a heat exchange between said ducts C1,C2,?CN and the electric motor 2, thus? that the electric motor 2 is cooled by means of said air jets.

Furthermore, advantageously, each duct C1,C2,?CN has an internal surface equipped with a respective plurality? of T1,T2,?TN protrusions to facilitate heat exchange.

In the first embodiment described, said casing 1 has a first length and each duct C1,C2,?CN has a respective second length equal to said first length.

In particular, the second end? of each duct C1,C2,?CN ? arranged on said second end wall? 1B of said casing 1 and each ventilation device F1,F2,?FN ? positioned at a respective second end? of each duct C1,C2,?CN.

Furthermore, in the first embodiment described, there are four said ducts C1, C2,?CN: a first duct C1, a second duct C2, a third duct C3, and a fourth duct C4.

Each of said ducts C1,C2,C3,C4 has a respective axis A1,A2,A3,A4.

In particular, the first duct C1 has a first axis A1, the second duct C2 has a second axis A2, the third duct C3 has a third axis A3, and the fourth duct C4 has a fourth axis A4.

As mentioned above, the first end? of each duct? one end? free.

In particular, the first duct C1 has an opening and a further opening, in which said opening is? facing the external environment.

The second duct C2 has an opening and a further opening, in which said opening is? facing the external environment.

The third duct C3 has an opening and a further opening, in which said opening is? facing the external environment.

The fourth duct C4 has an opening and a further opening, in which said opening is? facing the external environment.

Furthermore, as mentioned above, each duct includes an internal surface equipped with a respective plurality? of protrusions.

Consequently, the internal surface of the first duct C1 ? equipped with a plurality? of protrusions T1, the internal surface of the second duct C2 ? equipped with a plurality? of protrusions T2, the internal surface of the third duct C3 ? equipped with a plurality? of protrusions T3, and the internal surface of the fourth duct C4 ? equipped with a plurality? of T4 protrusions.

Since? the electrospindle has a ventilation device for each duct, there are four ventilation devices F1, F2,?FN: a first ventilation device F1, a second ventilation device F2, a third ventilation device F3, and a fourth ventilation device F4.

Said second end wall? 1B has a quadrangular or substantially quadrangular shape.

? preferable that the second extremities? of said ducts C1,C2,C3,C4 are arranged at the vertices of said quadrangular shape.

In particular, this quadrangular shape can? be a rectangle or a square.

In the embodiment described, called quadrangular shape? a rectangle.

In another embodiment of the present invention, the second ends? of said ducts C1,C2,C3,C4 can be arranged along the perimeter of said second end wall? 1B.

Returning to the casing 1, in the first embodiment described, said casing 1 comprises a first part 11 and a second part 12, in which said first part 11 and said second part 12 are coupled together in a removable manner.

Said first part 11 includes a first end wall and a second end wall, wherein said first end wall is ? the first end wall? 1A of casing 1.

Said second part 12 includes a first end wall and a second end wall, wherein said second end wall is ? the second end wall? 1B of casing 1.

In particular, each ventilation device F1,F2,F3,F4 occupies a respective portion of the volume of said second part 12.

Said first part 11 and said second part 12 are coupled to each other by means of coupling means. Said coupling means are coupling means of a known type.

In the first embodiment described, said coupling means comprise at least one hole (not shown) on the second end wall. of the first part 11 and at least one further hole (not shown) on the second end wall? of the second part 12 (i.e. on the second end wall of the casing 1), as well as? at least one connection element shaped to be inserted into a hole and into a further hole, so? to connect said first part 11 and said second part 12 to each other.

In the first embodiment described, said coupling means include four holes on the second end wall. of the first part 11 and four further holes on the second end wall? of the second part 12, as well as? four connection elements P1,P2,P3,P4.

In particular, each of said connection elements P1,P2,P3,P4? a pin.

With reference to the length of the ducts C1,C2,C3,C4 compared to the length of the casing 1, said casing 1 has a first length and each duct C1,C2,C3,C4 has a second length equal to said first length.

The second end? of each duct C1,C2,C3,C4? arranged on said second end wall? 1B of said casing 1, and each ventilation device F1,F2,F3,F4? positioned on a respective second extremity? of each duct C1,C2,C3,C4.

In particular, the first length of the envelope 1 ? given by the sum of the length of the first part 11 and the length of the second part 12 of the casing 1.

In a variant, shown in figure 5, said casing 1 has a first length and each duct C1,C2,C3,C4 has a second length shorter than said first length.

Each second end? of each duct C1,C2,C3,C4? inside the casing 1.

In particular, in this variant, the second extremities? of the ducts C1,C2,C3,C4 are arranged on the same plane inside said casing 1.

In particular, the second length of each duct C1,C2,C3,C4 ? equal to the length of the first part 11 of said casing 1.

Consequently, the second end wall? of said first part 11? arranged on said floor.

Figures 6 and 7 show a second embodiment of the electrospindle.

Differently from the first embodiment, the shaft 3 of the electrospindle includes inside a duct (not shown) for the passage of a liquid (such as water) to cool the tool U mounted on the electrospindle and/or the piece to be machined using said tool U.

In particular, said electrospindle includes a rotating joint (not shown) arranged inside said casing 1.

Said rotary joint includes a further duct inside it.

In particular, said rotary joint ? connected to said shaft 3 in such a way that said further duct is aligned and coaxial to the duct of shaft 3 for the passage of said liquid.

In particular, said rotary joint ? located inside the second part 12 of casing 1.

Furthermore, in an embodiment of the present invention, said electrospindle includes a respective sensor (not shown in the figures) arranged on each ventilation device F1,F2,?FN. By way of example, said sensor can? be selected between an encoder located on the motor of the ventilation device F1,F2,?FN, or a current meter.

Each sensor ? configured to detect a malfunction of the respective ventilation device F1,F2,?FN.

The present invention also refers to a machining head (not shown) comprising an electrospindle according to one of the embodiments described above.

The present invention also refers to a machine tool (not shown) for machining parts, comprising:

- a base,

- a work surface to support at least one piece, where said work surface is? placed on said base, ed

- a unit? of processing to work said piece, in which said unit? of processing includes at least one processing head mentioned above.

Advantages

Advantageously, the electrospindle which is the object of the invention is designed to cool the electric motor through a plurality? of ducts and a plurality? of ventilation devices, one for each duct.

An additional advantage? given by the fact that the structure of said electrospindle is designed to allow an operator to easily access one or more? components of the electrospindle compared to a known type electrospindle.

This invention? has been described by way of illustration, but not by way of limitation, according to its preferred embodiments, but? it is to be understood that variations and/or modifications may be made by experts in the field without thereby departing from the relevant scope of protection, as defined by the attached claims.

Claims (15)

1. An electrospindle including: - a casing (1) comprising a first end wall? (1A) and a second end wall? (1B), opposite to said first end wall? (1A), - a shaft (3) having a longitudinal axis (A), arranged at least partially inside said casing (1), - an electric motor (2) to rotate said shaft (3) around said longitudinal axis (A), arranged inside said casing (1), - a plurality? of ducts (C1,C2,?CN), obtained in said casing (1), in which each duct (C1,C2,?CN) of said plurality? of ducts (C1,C2,?CN) has a respective first end? and a respective second end, opposite to said first end, in which each first end? ? arranged on said first end wall? (1A) of said casing (1), - at least one ventilation device (F1,F2,?FN) for at least one duct of said plurality? of ducts (C1,C2,?CN), so? that a respective jet of air is emitted in said at least one duct (C1,C2,?CN), in which each ventilation device (F1,F2,?FN) is arranged on said second end wall? (1B) of said casing (1). 2. Electrospindle according to claim 1, comprising a respective ventilation device (F1,F2,?FN) for each duct (C1,C2,?CN), so? that a respective jet of air is emitted in a respective duct (C1,C2,?CN). 3. Electrospindle according to any of the previous claims, in which each duct (C1,C2,?CN) of said plurality? of ducts (C1,C2,?CN) has a respective axis (A1,A2,?AN), parallel to the longitudinal axis (A) of the shaft (3), in which each ventilation device (F1,F2,? FN) ? arranged along the axis (A1,A2,A3,A4) of a respective duct (C1,C2,?CN). 4. Electrospindle according to any of the previous claims, wherein said casing (1) has a first length and each duct (C1,C2,?CN) has a second length equal to said first length, wherein the second end? of each duct (C1,C2,?CN) ? arranged on said second end wall? (1B) of said casing (1), and each ventilation device (F1,F2,?FN) ? positioned on a respective second extremity? of each duct (C1,C2,?CN). 5. Electrospindle according to any one of claims 1-3, wherein said casing (1) has a first length and each duct (C1,C2,?CN) has a second length less than said first length and the second end? of each duct (C1,C2,?CN) ? arranged on the same plane inside said casing (1). 6. Electrospindle according to any of the previous claims, wherein said casing (1) includes a first part (11) and a second part (12), wherein said first part (11) and said second part (12) are coupled in removable from each other, in which said first part (11) includes said first end wall? (1A) of said casing (1) and said second part (12) includes said second end wall? (1B) of said casing (1). 7. Electrospindle according to claims 5 and 6, wherein the second length of each duct (C1,C2,?CN) is equal to the length of said first part (11) of said casing (1). 8. Electrospindle according to any one of the preceding claims, wherein said ducts (C1,C2,?CN) are four and said ventilation devices (F1,F2,?FN) are four. 9. Electrospindle according to any of the previous claims, wherein said second end wall? (1B) has a quadrangular shape, in which the second ends? of said ducts (C1,C2,?CN) are arranged at the vertices of said quadrangular shape. 10. Electrospindle according to the previous claim, wherein said quadrangular shape is? a rectangle or square. 11. Electrospindle according to any of the previous claims, wherein said shaft (3) includes inside it a duct for the passage of a liquid, e wherein said electrospindle comprises a rotary joint, arranged inside said casing (1), wherein said rotary joint comprises a further duct inside it and is? connected to said shaft (3) in such a way that said further duct is aligned and coaxial with said duct for the passage of said liquid. 12. Electrospindle according to any of the previous claims, in which each duct (C1,C2,?CN) has a respective internal surface equipped with a respective plurality? of protrusions (T1,T2,?TN). 13. Electrospindle according to any one of the previous claims, comprising a respective sensor arranged on each ventilation device (F1,F2,?FN) and configured to detect a malfunction of said ventilation device (F1,F2,?FN). 14. Machining head comprising an electrospindle according to any one of the preceding claims. 15. Machine tool for processing parts, including: - a base, - a work surface to support at least one piece, where said work surface is? placed on said base, ed - a unit? of processing to work said piece, in which said unit? of processing includes at least one processing head according to the previous claim.