Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
  • B23Q17/002—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring the holding action of work or tool holders
  • B23Q17/003—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring the holding action of work or tool holders by measuring a position
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B31/00—Chucks; Expansion mandrels; Adaptations thereof for remote control
  • B23B31/02—Chucks
  • B23B31/24—Chucks characterised by features relating primarily to remote control of the gripping means
  • B23B31/26—Chucks characterised by features relating primarily to remote control of the gripping means using mechanical transmission through the working-spindle
  • B23B31/261—Chucks characterised by features relating primarily to remote control of the gripping means using mechanical transmission through the working-spindle clamping the end of the toolholder shank

Definitions

• the present invention relates to a wholly new tool spindle that has built-in multiple functions to simplify and assure the function of the spindle of the tool even at very high speeds of rotation.
• the invention is distinguished by the features stated in the characterizing parts of the claims and will be described in more detail in the form of examples with reference to the drawings.
• Figs. 1-4 show schematically examples of the tool spindle according to the invention, whereby the spindle, due to the its rotational symmetry, is only shown as half a cross-section.
• Fig. 5 shows another design of the invention in section and
• Figs. 6 and 7 shows cross-sections through the spindle axle along lines VI and VII in Fig. 4 and Fig. 8 shows schematically the supply unit connected to the spindle according to the invention.
• the rotating spindle axle is designated with 1 and in the example shown in Fig. 1 is supported on two ball-bearings, indicated by 2, or alternatively on two fluid bearings 24 (Fig. 5).
• An axially displaceable pulling rod 3 extends in the centre of the spindle axle.
• a tool (not shown) can be attached firmly at the spindle axle 1 by being attached to the pulling rod 3 that is axially displaceable in the spindle axle.
• the pulling rod 3 extends into a unit 4 that is stationary in relation to the rotation of the spindle 1.
• Cooling of the tool A connection for a cooling agent, indicted by 5, to which a tube or hose is connected through which a cooling agent, for example, an emulsion is pumped under pressure through a central hole 6 in the pulling rod 3 is arranged centrally at the stationary unit 4.
• the cooling agent exits the pulling rod at the connection to the tool to cool the bits of the tool in a manner that is well known.
• the coolant is supplied, as stated, under pressure, which is why the coolant (fluid) will leak in the gap between the stationary unit 4 and the rotatable pulling rod 3 from the area with the fluid under pressure - the area before the inlet of the bore 6 - to a first outlet 8, which has a lower pressure than the pressure of the supplied coolant.
• This gap in forming a gap sealing, creates a pressure drop that constitutes a sealing function. As the gap is small, only an insignificant part of the total flow of the coolant will pass through the gap.
• the fluid in the gap will act as a dynamic fluid bearing and form a radially stabilising force on the rotating pulling rod 3. The fluid will also conduct away the heat of friction that is formed in the dynamic fluid bearing.
• unit 4 is equipped with a spool 9 into whose opening the end of the pulling rod 3 that is currently in unit 4 extends.
• the spool 9, which is stationary in relation to the axial displacement of the pulling rod 3, will generate different current flow depending on the axial position of the pulling rod in the spool 9.
• the signals carrying the information about the position of the pulling rod 3 are led in optical fibres to a unit outside of the spindle, for example, a computer or other control equipment, for example in the case that the actual data unit is situated in the spindle axle, for transformation to accessible information with the aid of er se known technology.
• spool 9 can in principle surround pulling rod 3 at any location, as long as the pulling rod at this location has a significant change of material.
• Fig. 1 shows a tool spindle from which it is evident that the pulling rod 3 is provided and integrated with a piston 11.
• the pulling rod 3 also has bores 12a, b, c distributed around the centre.
• the piston 11 is displaceable in a cylinder chamber 13 that is accommodated in the spindle axle 1.
• the pulling rod 3 is withdrawn in the spindle axle 1 , thereby firmly holding the tool (not shown).
• hydraulic fluid is supplied under pressure through an inlet 16 at unit 4 and led into at least one first bore 12a of the pulling rod 3, which opens adjacent to the inlet 16.
• the gas under pressure seeks a passage through a gap sealing also towards the left (as seen in the Figures) and out through an outlet 8'.
• the area pressurised via inlet 16 is limited as the fluid together with the gas (blocking air) exit unit 4 via outlet 8'.
• the hydraulic fluid is led via the bore 12a into the cylinder chamber 13 on the right-hand side of piston 11 (according to Fig. 1) and forces the piston to the left. The pulling rod 3 will thus be displaced to the left, allowing the removal of the tool.
• At least one second bore 12b which is not the same as previously named in connection with opening 16 and which is sealed off at the end adjacent to opening 16 (Fig. 2), is provided with one or more openings 14' distributed peripherally in a radial plane and always located in communication with an inlet 14 of unit 4 that is divided in a radial plane and axially separated from inlet 16 by a gap sealing 14". Hydraulic fluid under pressure is supplied to the inlet 14 (whereby inlet 16 naturally is not under pressure) and is led via the second bore 12b into the cylinder chamber 13 on the left-hand side of piston 11 (according to Fig. 2) forcing the piston 11 to the right, thereby displacing the pulling rod to the right for tightening the tool.
• the pulling rod 3 is held in this position by the pressurised hydraulic fluid continuously acting on the left-hand side of the piston.
• the hydraulic liquid will also leak in the gap sealings between unit 4 and the pulling rod 3 both to the right and to the left when seen in the figure.
• the pressurised fluid provided through inlet 14 is restricted to its left (Fig. 2) by a gap sealing as well as an outlet 18 or a channel with atmospheric pressure and to the right of the gap sealing by the gap sealing plus the inlet 16, which as already mentioned is now not under pressure.
• Pressurised air (blocking air) is also provided through an inlet 17 of unit 4 that is divided in a radial plane, which also prevents further leakage of hydraulic fluid to the left (in the figure) and that together with the leaking hydraulic fluid, exits unit 4 via outlet 18.
• an outlet 19 with a lower pressure is arranged to the left of inlet 17.
• Bore 12a is open at the inlet 17 and opens to the right of piston 11, while the second bore 12b is provided with openings 14', is sealed at the end adjacent to inlet 16, and opens in the cylinder chamber 13 on the left-hand side of the piston.
• Six channels 20b of these twelve channels have restrictions 21 at the connection with the cylinder chamber 13 for maintaining the pressure in the cylinder chamber and for controlling the desired amount of flow in the channels 20a, and they are, at the opposite ends to their restrictions, connected with the other six channels 20a, that are plugged tight 21 ' at the cylinder chamber 13. Instead, these latter six channels 20a open at the first bore 12a of the pulling rod 3, which is inactive under these conditions, to lead away the hydraulic fluid via the inlet 16 that is inactive while the tool is attached.
• the pressurised air inlet 17 of unit 4, shown in Fig. 3 divided in a radial plane, with continuous pressurised air switched on during use is connected to at least a third bore 12c of pulling rod 3, which is plugged tight at its right-hand end in the Figure.
• the pressurised air here referred to as scavenging air
• the flow of pressurised air will be automatically broken through the tool with cone and flange sealing channels 23.
• Fig. 5 shows the invention applied to a tool spindle 1 supported by a fluid bearing schematically shown and indicated by 24.
• this embodiment can be said to correspond to that described previously in connection with ball-bearings with the difference that the channels 20b do not open in the cylinder chamber 13 but are, for example, tightly plugged at this.
• Coolant water is introduced via unit 4 through an inlet 25 divided in a radial plane and into the bores 12d of pulling rod 3, which are tightly plugged at their right-hand ends in the figure, and led via these bores 12d into the cooling channels 26 equally distributed around the centre axis of the spindle axle 1.
• the ends of the outlets of the cooling channels are provided with restrictions 27 to obtain the desired level of flow in the channels and draining of cooling water from the spindle axis at the channels 26.
• the spindle is surrounded by an atmosphere under pressure, e.g. continuously supplied pressurised air, enclosed in a housing 33, i.e. air under pressure is thereby continuously introduced in gap sealing 29' between the pulling rod 3 and unit 4, which means that cooling water leaking in the gap is prevented from forcing its way out into the said gap but is instead collected in an outlet 28 for onward transport from unit 4.
• a secure function of the described spindle can be achieved through the supply of fluid for the respective function taking place through supply channels that are independent of one another, especially through the most sensitive sections, for example where flexible connections are required.
• Fig. 8 shows schematically the supply unit according to the invention, designated by F, for the functional supply of the tool spindle, which as according to that described previously, includes the spindle axle 1 and its ball-bearings 2 respective fluid bearings plus the gap sealings that are included.
• the receiving and processing system 9F for the current flow or optical signals from the spool 9 at the tool spindle, with the aid of which the axial position of the pulling rod 3 can be determined, is shown on the right in Fig. 8.
• a coolant fluid with a pressure of 10-140 bar is fed to the tool cooling system 5F, which consists of, when viewed in the direction of flow, a cut-off valve 501, a check valve 502 and a pressure monitor 503, which senses that the said pressure falls within predetermined limits. Coolant fluid fed to the tool spindle that has passed gap sealing is led away and is indicated symbolically with the arrow 504.
• Protective air or blocking air with a minimum pressure of 6 bar is fed to inlet 7 via a cut-off valve 701 in the blocking air pathway 7F plus a pressure monitor 702, a check valve 703, an accumulator 704 and a regulator 705, the latter of which adjusts the outgoing pressure to desired pressure.
• the line from regulator 705 connects with at least two supply channels 706 that are independent of one another, each having a pressure monitor, and connected to inlet 7 of the tool spindle.
• Pressure monitor 702 monitors that the correct pressure prevails in circuit 7F.
• the pressure drop is sensed by the pressure monitor 702 and the accumulator 704 in circuit 7F is automatically connected, at the same time as a signal that the supply of energy for the operation of the tool spindle is to be interrupted is emitted.
• the accumulator is emptied successively and has a capacity that allows removal of fluid from locations, where it is not desired, the whole time up to and following the stoppage of the spindle.
• circuit 16F For cooling the spindle - rotor 22 - coolant is supplied via circuit 16F with a pressure of, for example, 6 bar.
• This circuit includes, in the order of the direction of flow, a flow monitor 161 that senses that a sufficient level of flow exists in the circuit, a pressure monitor 162 according to that stated earlier, a check valve 163, an accumulator 164, a regulator 165 plus a check valve 166, before this circuit connects to or feeds two supply channels 167 that are independent of one another, each having a pressure monitor and connected to the inlets 14, 16 of the tool spindle. Accumulator 164 holds a certain amount of fluid with a pressure of 6-7 bar.
• This accumulator 164 acts in principle in the same way as accumulator 704 in the circuit 7F and thus is responsible for that the spindle - rotor 22 - is supplied with coolant fluid for as long as the spindle rotates.
• the regulator 165 adjusts the outgoing pressure to the desired pressure, for example, 6 bar.
• the coolant fluid exits the spindle via channel 31 (see also Fig. 5).
• the feed system 24F for supplying fluid to the fluid bearing 24 of the tool spindle is shown furthest to the left in Fig. 8.
• the fluid is supplied to the system with a pressure of, for example, 100 bar and flows through a pressure monitor 241 , a check valve 242, and accumulator 243, suitably a flow monitor 244, a check valve 245 to be then led to the spindle via at least two supply channels 246 that are independent of one another and include a respective pressure monitor 247.
• the different components have in principle a function that is equivalent to that previously described in connection with system 7F and 16F.
• the task of the flow monitor 244 is to register that the correct amount of fluid - flow - passes.
• Hydraulic circuit 14F is arranged for adjusting the hydraulic system, for the pressure-setting of the different sides of the piston 11 for attaching or removing the tool.
• a branched line, to which a regulator 141 and a check valve 142 is connected, is arranged after the accumulator 243 in circuit 24F and before the flow monitor 244, after which the branched line connects to a multi-way valve, a so-called four-two valve or cross-parallel valve 143.
• the regulator is adjusted to a pressure of, for example, 60 bar.
• the pressurised hydraulic fluid is led out via valve 143 through at least two supply channels 144 that are independent of one another and provided with pressure monitors, and in via the inlet 14 of the tool spindle for displacing the piston 11 to the right (see Fig.) and attaching the tool.
• the line 145 connected from the valve 143 to the inlet 16 of the tool spindle is not under pressure so that the hydraulic fluid can be led away.
• the valve 143 is turned so that pressure is released from the connection 144 and the line 145 is pressurised.
• a pressure monitor 146 is arranged in the line. The return of the said fluid is led away via line 147.
• branched line 707 Part of the branched line 707 connected to system 5F between check valve 502 and pressure monitor 503 extends from system 7F after its regulator 705 via check valve 708. Another part of the branched line 707 connects to system 24F upstream of its supply channels 247 via a check valve 708a. Branched line 707 also connects to valve 143 of system 14F via a check valve 709, and similarly via a check valve 710 to system 16F downstream of its check valve 166.
• the said pressure and flow monitors signal when the prevailing values lie outside of the intended limits and cut off the supply of energy to the spindle axle.
• the invention described here is not limited to exactly the design described as the tool spindle can naturally be given another construction.
• the spindle axle 1 can extend into and be accommodated by the stationary part 4, whereby the gap sealings will be located between this and the spindle axle 1.
• the pressures specified in connection with the described supply system are appropriate but are given only as examples and can naturally vary depending on different parameters. Parts 244-247 do not apply when ball-bearings are used and instead, the system have lubricant monitoring of the ball-bearings added to it.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Gripping On Spindles (AREA)
• Turning (AREA)
• Auxiliary Devices For Machine Tools (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20414961

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (2)

• 1999
  • 1999-03-23 SE SE9901048A patent/SE519282C2/sv not_active IP Right Cessation
• 2000
  • 2000-02-16 WO PCT/SE2000/000304 patent/WO2000056489A1/en active Application Filing
  • 2000-02-16 AU AU29568/00A patent/AU2956800A/en not_active Abandoned

Patent Citations (2)

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