DE2537758C2 - Turntable assembly for turntables - Google Patents

Description

The invention relates to turntable assemblies for turntables with a turntable which is on a base is rotatably supported by a bearing assembly, and a motor for generating a turntable operating speed of the turntable (e.g. 16 rpm, 33 rpm, 45 rpm and 78 rpm).

Usually the platter is supported by a solid / solid contact bearing arrangement, which bearing arrangement can be a bearing of the motor. Such designs are satisfactory in very many cases, however, require a considerable manufacturing cost to obtain high quality for modern ones Hi-Fi systems. In particular, problems arise when attempting to maintain a constant in an economical manner To achieve rotational speed that is substantially free of torque fluctuations, which cause a rumble, whine and rapid pitch fluctuations, and without being vertical Vibrations are transmitted through the bearing arrangement of any supports of the device.

The invention is based on the object of a bearing arrangement for a turntable to develop which prevents pitch disturbances due to torque fluctuations or through vertical vibrations Any supports for the device by the Bearing arrangement are transferred.

According to the invention, this object is achieved by the turntable arrangement solved for turntables with a turntable, as characterized in claim 1 Is.

For this purpose, the one according to the invention differs Turntable assembly of the above known arrangements in that the bearing arrangement hydrodynamic 1st and a fluid of high viscosity between the relatively rotatable parts of the Arrangement is located and has pumping grooves for supporting the turntable axially and radially, the grooves sized and directed and the fluid has a viscosity such that the platter is without solid / solid storage contact is stored at speeds below the turntable operating speed. Such The bearing arrangement generates pressure when it rotates, so that an overpressure film (e.g. made of oil, Mercury or fat or a combination thereof, for example mercury sealed with a the mercury floating fat layer) in order to maintain the storage separation. It it has been found that the torque fluctuations typical of conventional bearings are essentially the same are turned off.

A suitable form of such a storage arrangement is referred to as a spiral groove storage, in which at least one of its bearing elements contains grooves which are essentially in Archimedean spiral paths extend and generate the forces mentioned.

In operation, the turntable and the moving part of the motor float on film or on films of the fluid in order to avoid solid / solid contact and to enable the platter to move at a constant speed with essentially no bearing rumble, whine, or pitch fluctuations or vertical vibrations that are transmitted via the bearing from the support will.

For a turntable that is intended for private use, an oil or Grease of sufficient viscosity can be used to store the platter at a speed that is well below the turntable's lowest operating speed (16 rpm) and does not leak if the platter is reversed.

For a better understanding of the invention and how it can be carried out, for example Reference is made to the accompanying drawings and specifically shows:

Fig. 1 is a view in section through the center line an embodiment of the turntable assembly according to the invention;

F i g. 2 a part of a hydrodynamic bearing; FIG. 3 shows a preferred form of storage for the turntable arrangement according to FIG. 1;
FIg. 4 shows a detail of FIG. 3.
Fig. 1 shows a view in vertical section through the axis of rotation of a turntable arrangement with a circular, non-magnetic turntable 1, which is mounted for rotation in an approximately horizontal plane and on the top of which a centering pin 7 is attached, which is received by the central opening of a record. The turntable 1 is also provided with the journal part of a hydrodynamic bearing 2 in the form of a truncated cone on its underside, furthermore with a simple labyrinth arrangement 3 to keep the ingress of dust as low as possible, and with a thin electrically conductive cylinder 4, the rotates in the gap of a motor stator 5. An underframe 6 is used to attach the motor stator 5 and forms in its center the receiving part or the shell of the hydrodynamic bearing 2. This receiving part also has the shape of a truncated cone, but in this case the lower flat surface of the receiving part is designed with suitably curved recesses , as in Flg. 2 Shown in plan view are the effects of the hydrodynamic bearing

to enable. If necessary, this can be done To be provided in the Zapfenlell of the storage. In general, storage can be based on the principles and with the characteristics of well-known hydrodynamic spiral

Groove bearings, regardless of whether they have a flat, spherical or conical shape, are designed.

The recesses or grooves can be formed on both bearing parts, and can also be formed on the conical surface of at least one of the parts can be provided. In addition, the recesses or grooves Have hydrofoil shape.

The storage is filled with a suitable oil or fat so that a fluidic storage film is created, and the oil or fat is of high viscosity, so that the turntable! fully through the film at low speed (for example 7 rpm and in any case below 16 rpm) is stored and the fat or oil does not leak out, when the device is reversed.

An embodiment of the invention is described in connection with FIG. 3 and 4. In this embodiment, a bearing is provided which is intended for operation in only one direction at 30 to 50 U / mln and is fluidically stored at 7 U / min. The bearing is hydrodynamic with an axial bearing 12 and radial bearing 14. The axial bearing 12 is of the type with around the center (Fig. 4) and with inward pumping grooves 13. When using oil with a viscosity of 0.175 10 " ⁶ Re kp s / cm ² (2.5 χ 10- «Reyns. Ib. sec / in. ² ) the axial bearing dimensions can be as follows:

Number of grooves
Depth of the grooves

Slot angle Q
Groove / rib ratio
Outer radius of the grooves
Inner radius of the grooves

10 to 15

127 χ ΙΟ-Ίηΐη

(5x10- "inches)

74.5 °

25.4 mm (1 inch)

12.7 mm (0.5 inches).

Double the diameter. The length of the shaft 15 for receiving the two radial bearings is approximately three times the bearing diameter. These radial bearings are provided for a radial play between the shaft 15 and the bushings 18 of not more than 25.4 χ IvH mm (1 χ 10 " ³ ") and not less than 127χ 10 " ⁴ mm (5XlO ^-4 "). With this design, the optimal slot angle is 23.26 degrees and the axial slot length is 11.43 mm (0.45 "). The slot-to-rib width ratio is 1: 1.

The storage arrangement described above is suitable in those cases in which, after the oil Has been introduced into the bearing assembly, the turntable assembly does not incline excessively is subjected. However, if it is necessary to add the oil and then tilt the device, O-rings can be used 19 to be provided in the arrangement to along with some suitable during transport removable elements to serve as a seal.

30th

45

Theoretically, the grooves are equiangular spirals, but ^J5 is not absolutely necessary as circular arcs are sufficient.

With this design, the bearing should have a working distance of about 50 x 10 " ⁴ mm (about 2 x 10" * inches). The grooves are formed on the base of a cylindrical shaft 15 and cooperate with a low-friction plate 16 which is glued synthetic resin to a support plate 17 made of mild steel.

For the radial bearing of the turntable assembly, a number of mutilated bearing surfaces are provided just as inclination pillow bearings can be used, all of which have a certain storage stiffness result in an unloaded state. Although a purely radial load hardly occurs, the storage must be a Moment of 28.77 kg / cm (0.25 lb. inches) plus that withstand possible moment caused by the offset load of the main axial load.

Pivoting countersink bearings are likely not beneficial in terms of cost, but can be hydrodynamic Bearings with surface mutilations or regulated runout half-speed vortex oscillations suppress and seem appropriate; the herringbone groove shape is likely of the mutated storage areas be most effective and appropriate in the present context. Since a nominal thrust bearing diameter of 25.4 mm (1 ") and a length of 101.6 mm (4") are possible, a double wheel bearing arrangement is for this embodiment shown, although a single radial bearing would also be possible.

In the particular embodiment shown, the axial length of each individual radial bearing is 14 about half of the LagerdurCimessers and the Absland between the centers of the camps is about this

60

b5 For this 2 sheets of drawings

Claims (3)

Patent claims: J. Turntable assembly for turntables with a turntable, which is on a base by a Bearing arrangement is mounted, and a motor for generating a turntable operating speed of the Turntable, characterized in that the bearing arrangement (2) is hydrodynamic, whereby a fluid of high viscosity is located between the relatively rotatable parts of the bearing assembly and Has pump grooves for the axial and radial mounting of the turntable (1), which grooves are dimensioned and are directed that the fluid has such a viscosity that the turntable (1) without solid / solid bearing contact is stored at speeds that are below the operating speed of the turntable. 2. Arrangement according to claim 1, characterized in that the pump grooves are curved (F i g. 2). 3. Arrangement according to claim I or 2, characterized in that the bearing arrangement and their Fluids are such that the platter rests on the fluid at a speed below 16 rpm with no solid / solid bearing contact can be stored.