JPS5846938B2 - Hand piece motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention comprises a rotor supported on both sides in ball bearings, the outer ring of the ball bearing being supported axially and radially within the motor casing by spring-elastic elements; The present invention relates to an ultra-small motor for driving a dental band piece that is fixed in the axial direction by a holding member.

It is known in the electric motor field to radially support the outer ring of a ball bearing in a so-called 0-IJ configuration (Swiss Patent No. 396,184).

The attached rubber band certainly cushions the radial rocking.

In case of axial shock loads, the bearing cannot deflect axially.

In such an installation, axial shocks are therefore transmitted directly to the housing via the outer ring.

This results in increased operating noise and damage to the bearings.

Axially supporting the ball bearing using an axial spring and preloading it to fix it axially within the motor casing
It is known from German Patent No. 1207482.

However, this solution does not dampen the radially acting oscillations.

An electric motor in which the outer ring of the bearing is rigidly fixed axially in an intermediate position between the resilient molded part and the metal sleeve by means of a disc which is rotated in each case is disclosed in French patent No. 1320919. It is known from the publication no.

This elastic molded part, together with the metal sleeve inserted therein and surrounding the outer ring of the bearing axially and radially, is on the one hand relatively expensive to manufacture.

On the other hand, this device does not introduce significant manufacturing tolerances, since the bearing is fixed axially almost firmly by a disk that is firmly fixed to the motor casing.

Manufacturing tolerances, which relate, for example, to the placement of the bearing on the rotor shaft or to the screwing into the housing for receiving the bearing, necessarily lead to different and high preload forces.

The object of the invention is to provide an ultra-compact motor of the type mentioned at the outset, which simplifies the production of the rotor support and which can be assembled with relatively large adjustment tolerances, while reducing the noise during operation and the service life of the bearings. The key is to avoid being burdened with declines.

This object is achieved according to the invention in that the bearing is designed as a collar bearing and has a collar part on its outer ring, which collar part has a shoulder part on the housing part in an intermediate position of the spring-elastic ring. is supported and is provided with one or more elastic elements, which are displaceable by fixing the outer ring axially within the motor casing with an adjustable preload.

Both bearings have a constant axial play in both directions within the range of the ring deflection, so that axial shocks, such as those that occur, for example, during poling or grinding, are better absorbed by the resilient ring and the casing. is not transmitted.

In contrast to known constructions in which special rubber moldings must be provided for bearing support, the present invention allows the use of simple commercially customary sealing rings, so-called O-rigs.

In other words, according to the proposal of the present invention, approximately two effects can be obtained.

This means, on the one hand, that the rotor can be relatively easily and nevertheless precisely assembled into the housing, allowing relatively large manufacturing tolerances and, on the other hand, however, allowing maintenance of comparable preload forces.

Additionally, the use of commercially available resilient O-rings eliminates the use of relatively expensive rubber moldings as provided in known motor constructions, which ultimately improves the motor performance. Manufacturing costs can also be reduced.

Next, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 shows a perspective view of a dental bandpiece with a grip part 1 of the bandpiece supporting a drilling tool.

An ultra-small motor 2 for driving a drilling tool is connected to this grip portion 1.

The electrical energy supply to this micromotor 2 takes place via a conduit hose 3 .

This conduit hose 3 is connected by means of a connection 4 to the end of the micromotor opposite the grip.

FIG. 2 shows a partially cutaway vertical cross-sectional view of the ultra-small motor 2. As shown in FIG.

In FIG. 2, the rotor 20 is supported in the motor casing 21 on both sides by collar bearings 22,23.

One of them, the collar bearing 22, receives the drive shaft 9 of the motor.

The shaft of the correspondingly formed grip part 1 of the band piece is pressed onto the drive shaft 9, which is surrounded by a sleeve (not shown in the drawings) connected to the housing.

The band piece is locked against axial slippage in the pressed-over position using a fastening device, which is likewise not shown.

Both flange bearings 22 and 23 are rubber elastic i24 and 25, so-called 0.
- The IJ valve is elastically supported within the motor casing 21.

0- IJ Sonfugu, 25 each have bearing 22 on one hand
.

The diameter of the outer ring of the collar bearing 23 is slightly smaller than the inner diameter corresponding to the casing part 34, so that a slight axial movement of the bearing is possible.

The axial preloading of the bearing takes place in this case by means of two mating discs 33 which are in contact with the outer end faces of the outer ring 28 of the collar bearing 22 .

This disk is fixed in the axial direction by a sleeve, which is not shown.

In order to adjust the axial preload, the disc 33 can be replaced by a turnbuckle 35 inserted into the casing 21.

This turnbuckle pushes towards the 0-IJ Sonfugu with its shoulder.

Such an embodiment is shown in dashed lines in FIG.

In other words, in this case, the axial preload of the collar bearing is
2 or via an axially displaceable turnbuckle 35 pressing on the shoulder 30.

Both O-IJ rings 24,25 accommodate axial and radial rocking in their locations and also accommodate changes in length due to thermal expansion.

Due to the elastic housing of the bearing in the above-described manner, the noise during operation of the motor is also significantly reduced.

This is because there is practically no positive connection between the bearing and the motor housing.

A significant advantage of the device according to the invention is that the manufacture and assembly of the motor is simplified, since the localized fit tolerances required for known motor supports no longer have to be observed, and therefore the replacement of the bearings is facilitated. This means that it is possible to do so.

In addition, the adjustment tolerances are increased by inserting the mating disc.

This significantly simplifies the adjustment of the rotor and thus reduces the cost of the motor.

In addition to the above-mentioned advantages, the rubber-elastic housing of the rotor reduces the impact load in the axial direction of the small collar bearing 23.
-It means that it is softened by the ring.

Furthermore, if the ball bearing is formed as a flange bearing, the 0-
This has the effect that the ring is easily prevented from falling apart.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, and FIG. 2 is a partially cutaway sectional view thereof. DESCRIPTION OF SYMBOLS 1...Grip part of band piece, 2...Super heavy W motor, 5...Motor casing, 20...Rotor,
21... Motor casing, 22, 23... Collar bearing, 24.25... Ring of collar bearing, 26, 27... Collar portion of collar bearing, 30.31... Shoulder of motor casing,
33...Mating disc, 35...Turnbuckle.

Claims (1)

[Claims] 1 Dental equipment having a rotor supported on ball bearings on both sides, supported axially and radially in the motor casing by the outer rings of the ball bearings or spring-elastic elements, and fixed axially by retaining elements. In the ultra-compact motor for driving a medical band piece, the bearings 22.23 are formed as collar bearings, and the collar portion 26,
27, and this collar part has spring elastic i24,2
The shoulders 30, 31 of the casing parts 21, 32 are supported in an intermediate position 5 and are provided with one or more elastic elements 33, 35, which adjust the outer ring. axially fixed in the motor casing 5 with a possible preload, the collar bearing 2 being fixed for the axial preload.
The shoulder 30 of the casing part 21 of 2 is the turnbuckle 35
An ultra-compact motor for driving a band piece for dentists, characterized in that the motor is formed as a.