Drive device for displacing two linearly moveable components pertaining to a plastic injection moulding machine

• US 20040013764A1
• Filed: 04/30/2003
• Published: 01/22/2004
• Est. Priority Date: 11/14/2000
• Status: Active Grant

• Current Assignee: Bosch Rexroth AG (Robert Bosch GmbH)
• Original Assignee: Bosch Rexroth AG (Robert Bosch GmbH)
• Inventors: Dantlgraber, Jorg
• Granted Patent: US 6,913,456 B2
• Time in Patent Office: Days
• US Class Current: 425/574
• CPC Class Codes: B29C 2045/506 using a hydraulic transmission between drive motor and the axially movable screw
• CPC Class Codes: B29C 2045/5068 mechanical drive means in series with hydraulic drive means for axially movable screw
• CPC Class Codes: B29C 45/07 using movable injection units
• CPC Class Codes: B29C 45/5008 Drive means therefor

Abstract

A drive device which is intended for displacing two linearly movable components of a plastics injection-molding machine at least partly at successive times, in particular for displacing the injection unit for bringing the injection nozzle into contact with a mold and for displacing the injection mechanism for injecting polymer into the mold. With a known drive device, arranged downstream of an electric rotating motor are two clutches, by which rotational movements are transmitted on the basis of frictional engagement, and with which wear accordingly occurs. Each clutch is followed by a threaded drive, by which the rotational movement of the output element of a clutch is transformed into the linear movement of the machine component to be displaced. To make the known drive device for a plastics injection-molding machine less susceptible to wear and less costly in a first way the threaded drive is arranged between the electric motor and the two clutches and, for displacing the one movable component, the linearly movable drive output element of the threaded drive is able to be moved beyond the displacement distance necessary for displacing the other movable component. In a second way the electric motor is an electric linear motor with a linearly movable drive output element, arranged downstream of which in the force chains are the two clutches, and for displacing the one movable component, the drive output element is movable beyond the displacement distance necessary for displacing the other movable component.

Claims

1. A drive device for displacing two linearly movable components (10, 13) of a plastics injection-molding machine at least partly at successive times, in particular for displacing the injection unit (10) for bringing the injection nozzle (15) into contact with a mold and for displacing the injection mechanism (13) for injecting polymer into the mold, with an electric motor (45), by which the one movable component (13) can be displaced by means of a first clutch (55) and a threaded drive having a threaded spindle (51) and a spindle nut (50) and the other movable component (10) can be displaced by means of a second clutch (56), and with a blocking device (75, 95) at least for the one movable component (10, 13), characterized by the fact that the threaded drive (50, 51) is arranged between the electric motor (45) and the two clutches (55, 56) and, for displacing the one movable component (10, 13), the linearly movable drive output element (51) of the threaded drive can be moved beyond the displacement distance necessary for displacing the other movable component (13, 10).

3. The drive device as claimed in claim 1 or 2, characterized by the fact that the first component (10) can be displaced by the output drive element (51) in a first traveling range and the second component (13) can be displaced by the output drive element (51) in a second traveling range, which is completely separate from the first traveling range.

2. A drive device for displacing two linearly movable components (10, 13) of a plastics injection-molding machine at least partly at successive times, in particular for displacing the injection unit (10) for bringing the injection nozzle (15) into contact with a mold and for displacing the injection mechanism (13) for injecting polymer into the mold, with an electric motor (45), by which the one movable component (13) can be displaced by means of a first clutch (55), and the other movable component (10) can be displaced by means of a second clutch (56), and with a blocking device (75, 95) at least for the one movable component (10, 15), characterized by the fact that the electric motor is an electric linear motor with a linearly movable drive output element, arranged downstream of which in the force chains are the two clutches (55, 56), and that, for displacing the one movable component (10, 13), the drive output element can be moved beyond the displacement distance necessary for displacing the other movable component (13, 10).

4. The drive device as claimed in a preceding claim, characterized by the fact that in at least one force chain from the drive output element (51) to a displaceable component (10, 13) there is a hydraulic gear mechanism (60, 30;

80, 31) with a first piston-cylinder unit (60, 80), which has a first hydraulic piston (62, 82), bounding a first cylinder chamber (67, 87;

66, 86), and with a second piston-cylinder unit (30, 31), which is located closer to the displaceable component (10, 13) in the force chain and has a second hydraulic piston (32, 37), bounding a second cylinder chamber (36, 39;

35, 40), pressure medium being exchangeable between the first cylinder chamber (67, 87;

66, 86) and the second cylinder chamber (36, 39;

35, 40).

5. The drive device as claimed in claim 4, characterized by the fact that the piston-cylinder units (30, 31, 60, 80) are double-acting.

6. The drive device as claimed in claim 4 or 5, characterized by the fact that the second cylinder chamber (36, 39) can be shut off by a shut-off valve (75, 95) with respect to the first cylinder chamber (67, 87).

7. The drive device as claimed in claim 6, characterized by the fact that the shut-off valve (75, 95) is a seat valve, by which the second cylinder chamber (36, 39) can be shut off in a leak-free manner.

8. The drive device as claimed in one of claims 4 to 7, characterized by the fact that there is a second threaded drive (101, 102) with two drive elements (101, 102) in engagement with each other, of which the one drive element (101) can be driven in a rotating manner by a second electric motor (24) and of which one drive element (101) is arranged between the hydraulic gear mechanism (30, 60) and the displaceable component (13).

9. The drive device as claimed in claim 8, characterized by the fact that the displaceable component is the plasticizing screw (14) of an injection mechanism and that the plasticizing screw (14) can also be driven in a rotating manner by the second electric motor (24).

10. The drive device as claimed in a preceding claim, characterized by the fact that each clutch (55, 56) is electromagnetically operable.

11. The drive device as claimed in a preceding claim, characterized by the fact that a clutch (55, 56) comprises an input clutch disk (53, 54) and an output clutch disk (64, 84) which lies axially opposite the latter, can be entrained by the input clutch disk (53, 54) in the one direction of movement only when the clutch (55, 56) is operated and can be entrained by the input clutch disk (53, 54) in the opposite direction also by axial impingement.