DE8531919U1 - Balancing device for static balancing of grinding wheels - Google Patents

Description

Machine tools

.:;.:;:· factory

• : : : Adolf Waldrioh öoburg

"'" gmbh & Oo - ¹ - 863o Öoburg

Balancing device for static balancing of grinding wheels.

The invention relates to a balancing device for the static balancing of grinding wheels, with two balancing masses that are coaxial with the grinding spindle axis and are mounted on the spindle nose in the area of the grinding wheel holder, each of which can be rotated in the same or opposite direction relative to the grinding spindle by means of a gear drive that rotates with the grinding spindle and is driven by an electric motor, each with a gear ring and a pinion that meshes with the latter.

In such a known balancing device (GB-PS 9&THgr;2 &THgr;6&Bgr;) the two gear rings are provided at the rear end of the spindle. One gear ring is connected to the other via a rod arranged centrally in the grinding spindle.

a üJuchtmasse connected, while a concentric j

The gear wheel arranged on the rod connects the other gear ring with the second light mass. Furthermore, an electric servomotor is arranged centrally at the rear end of the grinding spindle, which is driven by a worm gear | _s

drives one of the gear rings. ijJIf this is the case, |

then the two balancing masses are driven in opposite directions.

i ben. Furthermore, in the drive train between the worm gear j

gears and the one gear ring also has a clutch ]

and a reversing gear. The connection is

to one snail, the other one drives

Worm via the reversing gear also the second tooth- _s

wreath in the same direction of rotation. The power supply to the |

electric actuator via slip rings, &udigr;&iacgr;&egr;&bgr;&egr; S

known balancing device has above all the $

3D Disadvantage that the ductile masses are arranged in the center of the spindle nose or in front of it and the hollow shaft is also

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2 -

the rod in the center of the grinding spindle. It is therefore not possible to accommodate an automatically acting clamping device in the center of the grinding spindle for clamping a clamping beam connected to the grinding wheel, as is described, for example, in DE-PS 3k 03 361. However, such an automatically acting clamping device is a basic requirement for a rapid grinding wheel change, which can preferably also be carried out with the aid of a grinding wheel changer.

ID can be carried out fully automatically. Therefore, only relatively small balancing masses can be accommodated in the spindle nose, so that the balancing capacity is relatively low. In addition, the known balancing device requires a relatively complicated and correspondingly expensive gear for driving the balancing masses in the same or opposite direction, which also requires a lot of space.

A hydraulically operating balancing device is also known (see brochure of the company LJalter Dittel GmbH, D-8910 Landsberg, ^I!(J .YDRO AUSt)JUCHTSYSTEM HBA 3DG1" or DE-PS 3k 03 361). Between the headstock and the grinding wheel holder there is a housing which concentrically surrounds the grinding spindle nose and is divided into three separate chambers in the circumferential direction. The housing has three concentric ring grooves on its rear side facing the headstock, each of which is assigned to one of the chambers. Each of the ring grooves has an opening in the area of the 3D chamber assigned to it which extends almost over the entire circumferential angle of the assigned chamber. Three stationary nozzle heads are provided for supplying a balancing fluid, each of which is connected to one of the

Ring grooves are assigned to the nozzle heads. Balancing fluid can be supplied to the chambers of the housing rotating with the grinding spindle via these nozzle heads in accordance with the vibration measuring devices. Balancing fluid only comes out of the respective nozzle head if the associated arc-shaped opening is in the area of the nozzle head when the housing _S rotates. When the grinding spindle stops, the chambers empty themselves automatically. This well-known balancing device has

&lgr;&pgr; ^ _5n y _nr -j;sil dsß the center of the spindle nose and also of the grinding spindle remain free of parts of the balancing device. However, since the cooling liquid is usually used as the balancing liquid and this only has a relatively low specific weight, this known balancing device has a low luminous capacity. Uninterrupted grinding operation is also not possible, because the chambers have to be emptied in the meantime. It is also a disadvantage that the chambers empty automatically when the machine is at a standstill.

Empty 2D, because it is therefore necessary to carry out a complete air compensation each time after starting up the grinding spindle.

The invention is based on the object of creating a balancing device for static balancing of grinding wheels of the type mentioned at the beginning, in which the center of the grinding spindle nose and the grinding spindle is free to accommodate a clamping device or the like and which also has a large balancing capacity. 30

This is achieved according to the invention in that each balancing mass consists of a balancing ring arranged concentrically to the grinding spindle axis with a mass center eccentric to the grinding spindle axis, that the two balancing rings are mounted in a housing concentrically surrounding the grinding spindles, that

I each balancing ring the gear ring is arranged directly

i is !and that to drive each üJucht ring at least one

§ own gear arranged on the housing, driving the pinion,

* 10 gear units are provided.

$ With the new balancing device, the light rings,

I the servomotors and also the gear transmissions all

?! in a housing concentrically surrounding the spindle nose

I 15. The parts of the alignment device therefore do not require any space in front of the spindle nose, in the center of the spindle or in the center of the grinding spindle, so that

I an automatic clamping device for clamping

| ^r and loosening the grinding wheel can be arranged.

f. 20 By arranging light rings that concentrically surround the spindle nose, the space available for the light rings, especially in the radial direction, is not limited by the dimensions of the spindle nose. Light rings of any size with a correspondingly high light capacity can therefore be used. By using at least one of each

j' Gear motor to drive each balancing ring and the entire structure of the actuator becomes simpler, because

\i clutches and a reversing gear are eliminated.

3Q above the above-described hydraulically operating I balancing device, the balancing device according to the invention has

I device above all the advantage of a significantly

higher balancing capacity. You can also continuously

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1D

grinding and balancing automatically, as the ^same air capacity is always available. Even when
When the grinding spindle is stopped, the previously formed bulge is retained, so that after starting
the grinding spindle can start grinding immediately
and no air compensation has to be carried out first. This is only necessary when starting up the grinding spindle if a grinding wheel adjustment has been carried out beforehand.

Advantageous embodiments of the invention are described in the
Subclaims are marked.

The invention is explained in more detail below using an embodiment shown in the drawing. It shows:

Figure 1 shows an axial section of the grinding spindle with the new alignment device,
Figure 2 shows a partial axial section of the balancing device etuia

in double size,

Figure 3 shows the front view of one of the light rings in different embodiments in direction II of Figure 2.
25

The grinding spindle 1 usually has a flange 2 and a short mounting cone 3 on its spindle nose 1a for receiving the mounting flange U of the grinding wheel 5. The
The mounting flange carries a clamping beam 6. In the center of the grinding spindle nose is a clamping bolt 6
collet 7 is arranged, which can be actuated by the pull rod &thetas; mounted axially displaceably in the center of the grinding spindle 1.

• I ·

• ·»

A housing 9 which concentrically surrounds the spindle nose is screwed to the flange 2 of the grinding spindle 1. The housing 9 is arranged between the headstock (not shown) and the grinding wheel 5 and its mounting flange k . In the housing 9, which can be composed of several parts, two balancing rings 1D, 11 are rotatably mounted concentrically to the grinding spindle axis A. The two balancing rings 10, 11 are expediently the same size and are mounted axially one behind the other in the housing 9. Each of the balancing rings 10, 11 carries a gear ring 12, 13 in the area of the opposite end faces 10a, 11a. The gear ring 12 meshes with a pinion ⁴ » which is driven by the gear motor 16. The pinion 15 of the gear motor 17, which is arranged diametrically opposite the gear motor 16, meshes with the other gear ring 13. A separate gear motor 15 or 17 is therefore provided for each of the two light-balancing rings 10, 11. A high gear ratio of approx. 1:900 and a short-circuit connection of the motor armature winding ensure that the drive of each light-balancing ring is locked in the state of the load compensation. In order to increase the holding torque of the locking during acceleration or deceleration processes, e.g. when starting up the grinding spindle or when stopping it, or when there are speed fluctuations, it can be useful to provide two gear motors per light-balancing ring.

In order to ensure that the balancing rings 10, 11 can be adjusted as easily as possible, they are mounted on ball bearings. In order to achieve the smallest possible bearing size, the balancing ring 10 has a truncated cone-shaped countersink 1Θ on its front side 10a facing away from the other balancing ring 11. The other balancing ring is mounted in the same way.

ring 11 is provided with a truncated cone-shaped recess 19. In addition, the light ring 11 has an annular groove 20 on its end face 11b facing the other light ring 1D. Several bearing balls are arranged in this annular groove 2D and also between the truncated cone-shaped recesses 18 and and the housing 9. These can optionally be made of low-friction plastic materials, such as polytetrafluoroethylene (PTFE = Teflon), instead of the usual alloy steel. If the light ring 10 is also provided with a groove corresponding to the groove 20, then both light rings 10, 11 are identical structures, which can reduce the manufacturing costs.

Each of the two grinding rings 10, 11 must have a mass center that is eccentric with respect to the grinding spindle axis A. In order to achieve this, each of the two grinding rings 10, 11 has several axially parallel holes 22 in one half of the ring, as can be seen from Figures 2 and 3 on the right. The mass of one half of the ring is reduced by these holes 22, whereby the mass center C of the grinding ring is moved away from the spindle axis A by the distance e.

If one provides a single large recess 23 instead of the axial bores 22, as shown in Figure 3 leftB and indicated in Figure 2 with dotted lines, then the mass center C1 takes an even greater distance el from the spindle axis A

and you can thereby increase the QJucht capacity even further.

-B-

The gear units 16, 17 are supplied with electrical energy at the rear end of the grinding spindle via sliding contacts (not shown). The power supply is controlled by a known electronic control device which receives electrical signals from a vibration sensor arranged on the headstock.

The balancing device works as follows:

When the grinding spindle is running, gear motors 16, 17 are initially driven at ¹ :1 in accordance with the electronic control device so that both air rings 10, 11 are rotated at the same speed and in the same direction of rotation relative to the grinding spindle 1 until the unbalance of the entire system reaches a minimum. The drive can initially be fast and then slow shortly before the minimum is reached. The centers of mass of the two air rings 10, 11 retain the same angle of rotation. The two air rings 10, 11 are then driven in opposite directions and at the same speed by the gear motors 16, 17. This increases or decreases the angle of rotation between the two mass centers of the two balance rings 10, 11. If the mass centers approach each other, the mass center resulting from both mass centers moves radially outwards relative to the grinding spindle axis A and vice versa, if the two mass centers move further away, it moves radially inwards. The two balance rings 16, 17 are driven in opposite directions until λ balance is achieved. Here, too , it is possible to start the gear motors 16, 17 quickly and shortly before reaching the

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-time of the balancing adjustment. When the balancing adjustment is achieved, the gear motors 16, 17 are stopped and a short circuit is made in the motor armature winding. Due to the high transmission ratio between the gear motors 16, 17 and the two balancing rings 1D, 11, these are locked in relation to the grinding spindle.

Claims (1)

- 10 - Expectations 1. Balancing device for the static balancing of grinding wheels, with air masses which are coaxial with the grinding spindle axis and mounted on the spindle nose in the area of the grinding wheel holder, each of which can be rotated in the same or opposite direction relative to the grinding spindle by means of a gear drive which rotates with the grinding spindle and is driven by an electric motor, each with a gear rim and a pinion meshing with it , characterized in that each air mass consists of a balancing ring (10, 11) arranged concentrically with the grinding spindle axis (A) with a mass center (C; CD) which is eccentric with respect to the grinding spindle axis (A), that the two air mass rings (10, 11) are mounted in a housing (9) which concentrically surrounds the grinding spindle nose (1a), that the gear rim (12, 13) is arranged directly on each air mass ring (10, 11) and that for driving each light ring (10, 11) at least one separate, arranged on the housing (9), the pinion (1U, 15) driving gear noto:- (16, 17) is provided. 2. Device according to claim 1, characterized in that both üjucht rings (10, 11) have the same size. and are mounted axially one behind the other in the housing (9). 3. Device according to claim 2, characterized in that the gear rings (12, 13) are arranged in the region of the mutually opposite end faces (10a, 11a) of the light rings (10, 11). k. Device according to claim 1, characterized in that each air ring (10, 11) has one or more recesses (22; 23) on one half of the ring to achieve an eccentric mass center (C; CD). 5. Device according to claim 4, characterized in that the recesses are axially parallel bores (22). Device according to claim 1, characterized in that each U-ring has a truncated cone-shaped countersink (18, 19) on its end face (10a, 11a) facing away from the other U-ring (1D, 11), and that at least one U-ring (19) has an annular groove (20) on its end face (11b) facing the other U-ring (1S), bearing balls (21) being arranged between the truncated cone-shaped countersinks (18, 19) and the inside of the housing and also in the annular groove (20).