DE102012000757A1 - Rolling bearing i.e. ball bearing, for use in dental hand instrument, has centering unit arranged on inner circumferential surface of outer bearing ring and/or at outer circumferential surface of inner bearing ring - Google Patents

Abstract

The bearing (10) has an outer bearing ring (14) and an inner bearing ring that is arranged between a set of rolling elements i.e. ball bearings (16). A sealing system comprises a sealing disk (20), and a support disk (22) that covers the sealing disk. The sealing disk and the support disk are arranged between two ball bearings. A centering unit of the sealing disk and/or the support disk is arranged on an inner circumferential surface of the outer bearing ring and/or at an outer circumferential surface of the inner bearing ring.

Description

Field of the invention

The invention relates to a rolling bearing with sealing system, in particular a ball bearing for high-speed applications with a sealing system and a device for ensuring a contact seal at a standstill of the ball bearing. Such a ball bearing is preferably used in dental hand instruments, so-called dental handpieces, which are rotationally driven by compressed air. In the operating state, the ball bearing is flowed through by the compressed air, wherein the flow of pressure, the touching seal from a contact surface (seal seat) lifts, d. H. opens and thus becomes a non-touching seal.

State of the art

Ball bearing with sealing system and contacting seals at standstill, which lift off the contact surface during operation, d. H. become non-contacting seals are difficult to assemble and very sensitive to vibration stresses. The sealing system comprises an elastic sealing washer and a support disc by which the sealing washer is axially supported and fixed. Important is a centric positioning of the annular sealing disc with respect to a contact surface, so that the sealing surface of the sealing washer rests over the entire circumference without gap formation on the contact surface or generates a defined circumferentially uniform gap. During assembly and due to the vibrations during operation, there is the possibility that the centric positioning of the sealing disc is not achieved or worsened. Eccentrically positioned gaskets can produce circumferentially varying gaps which interfere with the sealing action or cause increased wear at the contact point between the gasket and the abutment surface (eg, the inner ring). In addition, this worsens the desired reduction of the flow time due to the friction between the sealing washer and contact surface. Due to the vibration stress, the sealing system can be unintentionally dismantled, d. H. it may loosen the connection of the sealing system with the outer ring. The vibrations during operation can lead to an eccentric position of the sealing disc or to an increase of the eccentric position, which then leads to the aforementioned unfavorable conditions.

Furthermore, the sealing systems are typically centered and fixed in the outer ring of the ball bearing by means of a recess. In this case, the support disks and the gasket are fixed to the outer diameter in a groove on the outer ring in the radial direction. The centering of the sealing disk with respect to the contact surface (seal seat) with which the sealing gap or the overlap is formed depends on several concentricity and roundness tolerances.

An eccentric mounting of the sealing washer can lead to large gaps at the entire circumference or in areas around the circumference, and thus adversely affect the sealing effect. In addition, an eccentric mounting of the gasket on the entire circumference or in areas on the circumference can lead to excessive coverage, which cause large friction moments in the bearing and large wear of the gasket. This wear can lead to a loss of the sealing function.

When cleaning the device in which the ball bearing is operated, cleaning medium can penetrate into the ball bearing and remove the lubricant there or promote corrosion. Since the sealing system is typically arranged in the side facing away from the flow direction of the cleaning medium, the cleaning medium can freely penetrate into the bearing, since it is not retained by the sealing system.

By penetrating detergent lubricants are rinsed or discharged from the ball bearing and promotes corrosion. This can lead to a reduction in the life of the ball bearing, since the ball bearing is no longer sufficiently lubricated after the cleaning process during operation and thereby increases the wear of the bearing, which can lead to premature failure of the bearing.

Disclosure of the invention

It is the object of the invention to provide a rolling bearing, in particular a ball bearing, which has an improved sealing system and in particular is easy to install, ensures a better centering of the sealing washer and is insensitive to vibration and cleaning agents.

This object is achieved by a rolling bearing, in particular a ball bearing, with sealing system according to the features of claim 1.

Preferred embodiments and advantageous features of the invention are indicated in the dependent claims.

The rolling bearing, in particular ball bearing, with sealing system comprises an outer bearing ring and an inner bearing ring, between which Rolling, in particular bearing balls are arranged. The sealing system has an annular and elastic sealing disc and at least one sealing disk covering the annular support disk, said sealing disk and the support disk are arranged between the two bearing rings, and at resting rolling bearing a sealing surface of the sealing washer rests against a contact surface.

The invention is characterized in that means for centering the sealing disk and / or the support disk are provided on the inner peripheral surface of the outer bearing ring and / or on an outer peripheral surface of the inner bearing ring.

According to a first preferred embodiment of the invention, a recess with a preferably cylindrical guide surface is provided on the inner peripheral surface of the outer bearing ring, on which the sealing disk and the support disk are radially guided and centered. The centric position of the gasket is achieved by a special form of the recess, which ensures low running tolerances to the inner ring board and a good guidance of the gasket on the outer diameter. Serves the preferably cylindrical guide surface whose axial length L is dimensioned so as to accommodate the gasket with the axial length L1 and at least half the support disk with the axial length L2. It is L - L1 ≤ 0.5L2. This guide surface is manufactured with minimal radial run tolerance on the track.

The support disk is secured by a securing element against axial displacement. The securing element preferably bears with its outer circumference in a groove on the inner peripheral surface of the outer bearing ring, wherein the groove has a bevelled peripheral surface. By the securing element, which is formed for example as a clamping ring, the sealing washer and the support disc are securely pressed against a shoulder as an axial stop. The bevelled peripheral surface of the groove preferably has a slope of 30 ° +/- 10 ° with respect to the axis of rotation of the bearing. As a result, the radial clamping forces of the clamping ring are transformed into sufficiently large axial clamping forces. A radially extending impact surface at the outlet of the bevel creates a positive connection, which holds the clamping ring securely in the groove even with strong vibrations.

This sealing system withstands great vibration stresses, with a very good centric positioning of the gasket is achievable and thus wear on the contacting gasket is minimized. In addition, this favors the desired reduction of the flow time due to the friction between the sealing washer and inner ring.

In addition, it is advantageous, in addition to the frictional connection by the axial clamping forces of the securing element, to produce a material connection between the sealing disk and the one supporting disk or the two supporting disks. For this purpose, adhesive may be introduced through holes in the backing discs (made, for example, by stamping) at one or more locations positioned as far as possible from the puncture to protect the bearing row from penetration by the adhesive. Also, a fixation of the sealing washer between the two support disks by means of one or more welding points (eg laser welding points) is a possibility for secure centering of the sealing disk.

According to another advantageous embodiment of the invention, a recess with a cylindrical guide surface is provided on the inner peripheral surface of the outer bearing ring, radially guided and centered on the support discs. In particular, the sealing system may comprise two support disks, wherein the sealing disk is arranged between the two support disks. On the other hand, the sealing disk is guided and centered on the outer circumferential surface of the inner bearing ring. The centering of the sealing washer of the ball bearing sealing system thus takes place directly on the mating surface (typically the inner ring board of the rolling bearing). The centering of the support disks is unchanged in the groove of the outer bearing ring.

In this embodiment of the invention, a positioning of the sealing disc with respect to the support plate is preferably carried out during assembly of the sealing system, wherein the radial position of the sealing disc is fixed relative to the support plate by suitable means. In particular, the radial position of the sealing washer with respect to the support disks is z. B. by adhesion (axial clamping) or material bond (laser welding or gluing) fixed. Thus, an optimal radial centering of the sealing washer is achieved to the counter surface and thus minimizes or optimizes the gap or the overlap.

The means for fixing the sealing disc with respect to the support disks can be designed in various ways. For example, a securing element in the form of a clamping ring or a resilient element can be used. However, the means for fixing the sealing disc with respect to the support disks may also comprise an adhesive connection. When using an adhesive connection at least one bore is provided in the first support disk, which up to the Gasket comes up. After mounting and positioning of the support disks and the sealing washer, the bore is filled with adhesive, thereby fixing the sealing washer with respect to the support disks.

In the presence of two support disks, both the first support disk and the sealing disk may have at least one concentric bore. These concentric holes are filled with adhesive, whereby a fixing of the sealing disks takes place with respect to the two support disks.

However, the means for fixing the sealing disc with respect to the support disks may just as well comprise a welded joint.

When using a welded joint, both the first support disk and the gasket are each provided with at least one concentric bore in the case of using two support plates, wherein the support disks are welded together in the region of the holes and thereby the gasket is fixed with respect to the support disks.

Another possibility of fixing is that a first support disk has at least one bead-shaped recess which engages in at least one associated bore of the sealing washer and extends up to the second support disk. The second support disk is welded in the region of the recess with the first support disk and thereby the sealing disk is fixed with respect to the two support disks.

The rolling bearing according to the invention is in operation in a dental handpiece of a gaseous medium, usually compressed air, flows through, wherein the sealing surface of the sealing disc is lifted by the flowing medium of its contact surface. This reduces the friction of the sealing system and allows the bearing to rotate at high speeds.

In a further embodiment of the invention, the sealing system with lifting seal, d. H. with a sealing disc opening by an applied flow pressure, arranged on the flow direction of the gaseous medium side facing the rolling bearing.

In operation, the sealing disc is lifted by the compressed air in the dental handpiece of the contact surface (seal seat) on the inner ring of the ball bearing and thereby to the non-contacting seal.

In the absence of compressed air or at rest of the bearing, the sealing disc preferably moves back into the starting position due to its elastic properties and becomes a contacting seal, whereby the bearing is braked and particles are retained. The sealing washer is preferably made of an elastic Teflon material, optionally in combination with glass fiber or carbon fiber composite material. However, it is also possible to use other suitable elastic, for example rubber-like materials whose tribological properties (eg wear resistance and friction behavior) are matched to the application.

Also during the cleaning process of the dental handpiece, the sealing washer becomes a contacting seal and the seal provides effective protection against penetrating detergent.

• – Reversible Deformation durch Druckunterschied zwischen der Druckluft im Betriebszustand und dem Reinigungsmedien bei der Reinigung. In der Regel wird die Reinigung mit wesentlich geringerem Druck vorgenommen als die Druckluft, so dass die elastische Dichtungsscheibe beim Reinigungsprozess nicht von der Anlagefläche abhebt. Alternativ kann eine zweite, der ersten Anlagefläche gegenüberliegende Anlagefläche vorgesehen werden, gegen welche die Dichtungsscheibe während des Reinigungsprozesses gedrückt wird und das Lager somit abdichtet, wobei der Reinigungsprozess dabei einen deutlich größeren Druck aufweist, als die Druckluft während des Betriebs des Dentalhandstücks.
• – Reversible Deformation durch pH-Wert Einfluss. Die Dichtungsscheibe kann aus einem Material gefertigt sein, das bei einem bestimmten pH-Wert des Reinigungsmittels seine Form bzw. seine Elastizität ändert, so dass die Dichtungsscheibe beim Reinigungsprozess und Vorhandensein von Reinigungsmittel sicher an der Anlagefläche anliegt.
• – Reversible Deformation durch unterschiedliche chemische Zusammensetzungen der Druckluft im Vergleich zu den Reinigungsmedien. Die Dichtungsscheibe kann aus einem Material gefertigt sein, das bei einer bestimmten chemischen Zusammensetzung des Reinigungsmittels seine Form bzw. seine Elastizität ändert, so dass die Dichtungsscheibe beim Reinigungsprozess und Vorhandensein von Reinigungsmittel sicher an der Anlagefläche anliegt.
• – Reversible Deformation durch Temperaturunterschied. Die Dichtungsscheibe kann aus einem Material gefertigt sein, das bei einer bestimmten Temperatur des Reinigungsmittels seine Form bzw. seine Elastizität ändert, so dass die Dichtungsscheibe beim Reinigungsprozess und Vorhandensein von Reinigungsmittel sicher an der Anlagefläche anliegt.
• – Reversible Deformation durch Einsatz von Materialien mit Memory Effekt. Die Dichtungsscheibe kann aus einem Material mit Memory-Effekt gefertigt sein, so dass die Dichtungsscheibe bei Nichtanliegen von Druckluft sicher an der Anlagefläche anliegt.

The sealing disc is designed such that it always assumes its rest position at standstill of the bearing or in the absence of compressed air and fulfills the sealing function. This can be done by:

• - Reversible deformation due to pressure difference between the compressed air in the operating state and the cleaning media during cleaning. As a rule, the cleaning is performed with much lower pressure than the compressed air, so that the elastic sealing washer does not lift off the contact surface during the cleaning process. Alternatively, a second, the first contact surface opposite bearing surface can be provided, against which the sealing washer is pressed during the cleaning process and thus seals the bearing, the cleaning process thereby has a much greater pressure than the compressed air during operation of the dental handpiece.
• - Reversible deformation due to pH influence. The sealing disc may be made of a material that changes its shape or its elasticity at a certain pH of the cleaning agent, so that the sealing disc during the cleaning process and the presence of detergent safely rests against the contact surface.
• - Reversible deformation due to different chemical compositions of the compressed air compared to the cleaning media. The sealing washer can be made from a Be made of material that changes its shape or its elasticity at a certain chemical composition of the cleaning agent, so that the sealing washer during the cleaning process and the presence of detergent safely rests against the contact surface.
• - Reversible deformation due to temperature difference. The sealing disc may be made of a material which changes its shape or its elasticity at a certain temperature of the cleaning agent, so that the sealing disc rests securely against the contact surface during the cleaning process and presence of cleaning agent.
• - Reversible deformation through the use of materials with memory effect. The sealing disc can be made of a material with a memory effect, so that the sealing disc rests securely against the contact surface when no compressed air is present.

The contact surface (typically the inner race of the bearing) for the sealing washer is larger in outer diameter than the bore of the sealing washer. There is thus a positive obstacle when introducing the sealing disc in the rolling bearing. When inserting the sealing disc, therefore, the elasticity of the sealing disc or the thermal expansion properties of the material of the sealing disc and of the counterpart with bearing surface (eg inner ring) are utilized. The sealing washer is heated and the inner ring cooled down. As a result, the sealing disk can be moved over the positive obstacle of the contact surface and mounted in the intended position.

The contact surface for the sealing disc can also be formed by a separate annular component which is mounted on the inner bearing ring after assembly of the sealing disc. As a result, the sealing disk can initially be mounted in the bearing without obstruction.

The application of another component on the inner ring board can be done by traction, material connection or positive locking. In this case, the further component can be designed so that the sealing effect is increased or the flow action is optimized (eg increased flow resistance) and a labyrinth seal is produced.

Brief description of the drawings

1 shows a section through a compressed air-operated dental handpiece with built-in rolling bearings according to the prior art.

2 shows a section through a first embodiment of the rolling bearing according to the invention with sealing system.

3 shows a section of 2 with dimension sizes.

4A shows a partial section of the rolling bearing according to 2 with adjoining sealing washer.

4B shows a partial section of the rolling bearing according to 2 with open sealing washer.

5 shows a partial section through a second embodiment of the rolling bearing according to the invention with sealing system and two support disks.

6A shows a partial section through the second embodiment of the rolling bearing according to the invention with glued sealing system.

6B shows a plan view of the bearings of 6A ,

7 shows a partial section through the second embodiment of the rolling bearing according to the invention with welded sealing system.

8A shows a partial section through the second embodiment of the rolling bearing according to the invention with a variant of the welded sealing system.

8B shows a plan view of the bearings of 8A ,

9 shows a section through a third embodiment of the rolling bearing according to the invention with upstream sealing system.

10 shows an enlarged partial section through the rolling bearing according to 9 with open sealing system.

11 shows an enlarged partial section through the rolling bearing according to 9 with closed sealing system.

12 shows an enlarged partial section through the rolling bearing according to 9 with a separate element as a contact surface for the sealing washer

13 shows a section through the third embodiment of the rolling bearing according to the invention during the sterilization process.

Description of preferred embodiments of the invention

In 1 is the front part of a dental hand instrument (dental handpiece) shown. The figure shows a sectional view of the front part of the dental handpiece with a head housing 1 in which a rotor shaft 2 by means of rolling bearings 8th . 10 is rotatably mounted. At the rotor shaft 2 is a rotor 4 attached in the form of a turbine wheel, which is driven by compressed air.

At the end of the rotor shaft 2 can be an appropriate tool 6 be attached. The two roller bearing 8th . 10 can be formed in accordance with the invention, as described below with reference to the 2 to 12 is described.

2 shows a sectional view of a roller bearing according to the invention 10 which has an inner bearing ring 12 and an outer bearing ring 14 comprises, each having running surfaces, between which rolling elements, in particular bearing balls 16 are arranged. The bearing balls 16 are in the usual way in a ball bearing cage 18 held and guided.

At least on one side of the rolling bearing 10 a sealing system is provided, which consists of an annular and made of elastic material sealing washer 20 exists between the inner peripheral surface of the outer race 14 and the outer peripheral surface of the inner race 12 is arranged.

The sealing washer 20 is from a first support disk 22 covered, with sealing washer 20 and support disk 22 by suitable means, in particular here a clamping ring 24 , axially braced and thus secured against displacement.

For the seal to perform its sealing function effectively, is a good centering of the gasket 20 necessary with regard to the contact surface. The centric positioning of the sealing washer 20 is made by a special form of a puncture 26 on the outer bearing ring 14 ensured and by low running tolerances to board the inner bearing ring 12 and a good guidance of the sealing washer 20 at the outside diameter.

For this purpose, the puncture 26 in the outer bearing ring 14 a preferably cylindrical guide surface 26a on, at which the outer diameter of the sealing washer 20 as well as the outer diameter of the support disk 22 be guided and centered.

How to get in 3 detects, the guide surface has an axial length L, which is dimensioned to the sealing disc 20 with an axial length L1 complete and the first support disk 22 at least partially received with an axial length L2. Thus, the sealing disc 20 and the support disk 22 through the guide surface 26a centered in their position.

According to the invention, L - L1 ≥ 0.5L2. This guide surface 26a in the outer bearing ring 14 is manufactured with minimum radial clearance tolerance.

To the sealing washer 20 and the first support disk 22 Safe against the axial stop in the groove 26 to press and thus fix the radial centering, is preferably a clamping ring 24 in a corresponding section of the puncture 26 arranged. The puncture 26 also has an inclined surface 26b on which a slope of 30 degrees +/- 10 degrees with respect to the axis of rotation of the bearing 10 having. This bevel 26b transforms the radial clamping forces of the clamping ring 24 in accordance with axial clamping forces for fixing the sealing washer 20 and the support disk 22 ,

A radially extending impact surface at the outlet of the inclined surface 26b creates a positive connection that the clamping ring 24 holds securely in the groove even with strong vibrations.

The 4a and 4b show the sealing system when the bearing or during operation of the bearing.

In 4A is the rolling bearing 10 shown at a standstill. D. h., The rolling bearing is not traversed by compressed air from the dental handpiece. This is the sealing surface 20a the sealing washer 20 elastic at a corresponding contact surface 28a on, by a puncture 28 on the inner bearing ring 12 is formed. The rolling bearing is thus protected against external influences or sealed against leakage of lubricant from the bearing interior.

4B shows the sealing system during operation of the rolling bearing 10 where the bearing is from an airflow 30 is flowed through, so that the sealing surface 20a the sealing washer 20 from the contact surface 28a is lifted and the seal opens.

Thus, the friction of the seal assembly is removed and the rolling bearing 10 can turn freely. Will the air flow 30 interrupted again, the seal assembly closes by the elastic design of the gasket 20 and the rotation of the rolling bearing 10 is due to the resulting friction between the gasket 20 and the contact surface 28a on the inner ring 12 braked.

The closing effect of the sealing washer 20 is also supported by the sudden negative pressure that occurs when the airflow is suddenly switched off 30 occurs.

The in the 2 to 4B Sealing arrangement shown can be additionally fixed by appropriate measures and means, for example by adhesive or one or more welds, as explained in the following drawings and description.

5 shows a further preferred embodiment of a rolling bearing according to the invention 10 which in turn has an inner bearing ring 12 and an outer bearing ring 14 includes, between those in a ball bearing cage 18 arranged bearing balls 16 to run.

The sealing system comprises in this embodiment, a first support disk 22 and a second support disk 23 between which the sealing washer 20 is arranged. This arrangement of support discs 22 . 23 and sealing washer 20 can also by a clamping ring 24 be fixed.

As a sealing surface 20a the sealing washer 20 Here essentially serves the inner peripheral surface of the sealing washer 20 , which at standstill of the ball bearing at a corresponding contact surface 12a directly on preferably slightly conical periphery of the inner bearing ring 12 is applied.

The outer bearing ring 14 also includes a puncture 26 with a cylindrical guide surface 26a at which the two support disks 22 and 23 guided on its outer circumference and are centered.

The centering of the intermediate sealing washer 20 takes place directly on the contact surface 12a on the inner bearing ring 12 , The positioning of the sealing washer 20 with respect to the two support disks 22 and 23 will be set during assembly. The radial position of the sealing washer with respect to the support disks is z. B. by adhesion (axial clamping) or material bond (laser welding or gluing) fixed.

During the assembly process, first the second support disk 23 inserted in the groove and on the cylindrical guide surface 26a centered.

Then the sealing washer follows 20 , with minimum gap or minimum coverage with respect to the contact surface 12a on the inner bearing ring 12 is introduced. Now the first support disk 22 again with guide on the cylindrical guide surface 26a brought in. With a clamping ring 24 that is on an inclined surface 26b at the puncture 26 supports and generates an axially acting clamping force, the sealing disc 20 and the two support disks 22 . 23 axially pressed against each other and fixed so non-positively to each other.

The fixation of the sealing washer 20 and both support disks 22 . 23 may also be by other means as described below.

The overlap or the gap between the sealing surface 20a and the contact surface 12a or mating surface is determined solely by the dimension and the roundness of the hole in the sealing washer 20 certainly. All other tolerances such. B. the radial run of the bore of the sealing washer 20 to the outer diameter of the sealing washer or the radial clearance between the recess 26 and the board of the inner bearing ring 12 do not enter. As a result, the sealing gap is kept within very narrow limits or the friction of the sealing system in the idle state of the bearing 10 kept very low.

In addition to the traction, the fixation of the sealing washer and the two support discs 22 . 23 also be produced by material adhesion.

6A shows a section through a rolling bearing 10 essentially according to 5 , in which case the first support disk 22 at least one hole 22a having. Through this hole 22a Adhesive is placed in one or more places, with the bore 22a as far away as possible from the puncture 26 of the outer ring 14 should be arranged to protect the bearing row from penetration of the adhesive. The adhesive penetrates through the hole 22a and or the plurality of holes and glued to the first support disk 22 with the sealing washer 20 ,

6B shows a plan view of the arrangement of 6A ,

To optimize the flow of adhesive, the sealing washer can also be used 20 with one or more holes 20b or other openings that are substantially concentric with the bore 22a the support disk 22 is arranged. This is in 6 indicated. As a result, the adhesive flow to the second support disk 23 improved and the sealing washer 20 also with the second support disk 23 bonded.

After curing, the adhesive is the sealing washer 20 with respect to the two support disks 22 . 23 fixed.

In 7 is a fixation of the sealing washer 20 between two support disks 22 . 23 by means of one or more spot welds 23a , z. B. laser welding points, resulting in a secure centering of the gasket 20 results. For this purpose, the first support discs 22 as well as the sealing washer 20 each corresponding holes 22a and 20b on. The two support disks 22 . 23 are welded together and the sealing washer 20 thereby fixed.

Through the holes 20b and 22a the weld joint is improved with or without the use of welding filler.

In the 8A and 8B Another possibility of welding is shown if the weld is the sealing washer 20 should not penetrate. In this case, the first support disk 22 with one or more bead-like depressions 22b provided by the hole 20b the sealing washer 20 passes through and thereby a direct contact or a minimum gap to the second support disk 23 generated. This will ensure a safe penetration of the welded joint 23a through the sealing washer 20 to the second support disk 23 allows. The two support disks 22 . 23 are welded together and the sealing washer 20 thereby fixed.

Preferably, for fixing the sealing washer 20 between the two support disks 22 . 23 the welding under application of an axial force, which clamps the three discs together. Also special surfaces of the discs on the contact surfaces with each other, z. As sandblasted surfaces or corrugations, can favor the fixation of the discs with each other. Likewise, further beads or a plate-shaped design of the support discs 22 . 23 advantageous for a secure fixation of the discs with each other.

9 shows a further embodiment of a rolling bearing according to the invention 110 which has an inner bearing ring 112 , an outer bearing ring 114 as well as bearing balls 116 includes, between treads of the two bearing rings 112 . 114 are arranged and from a ball cage 118 be held and guided.

The sealing system is essentially the same as in 5 illustrated and described sealing system and includes a sealing washer 120 between two support discs 122 . 123 is held.

The fixation of the support discs 122 . 123 and the sealing washer 120 done by a clamping ring 124 , In contrast to 5 has the rolling bearing 110 a puncture 128 on the inner bearing ring 112 on which a contact surface 128a for the sealing surface 120a the sealing washer 120 forms, similar to the sealing system according to 2 is described.

Will the storage system of a flow of air 130 flows through, so lifts the sealing surface 120a the flexible sealing washer 120 from the contact surface 128a From and the air flow can flow through the camp.

10 shows an enlarged view of the sealing system of 9 on average, here the sealing washer 120 in the open state, ie under the action of an air flow 130 is shown.

The bearing according to the invention is preferably arranged in a dental hand instrument, in particular a dental handpiece. The dental handpiece must be cleaned and sterilized on a regular basis, whereby in previously known sealing systems, which were arranged on the side facing away from the flow direction of the pressure medium, occurred again and again that the cleaning medium could penetrate into the bearing, since the sealing washer by the cleaning agent of their contact surface was lifted off.

In the in the 9 to 11 illustrated bearings 110 the sealing system according to the invention on the side facing in the flow direction of the pressure medium side of the rolling bearing 110 arranged.

In operation of the rolling bearing 110 becomes the sealing washer 120 by the compressed air from the contact surface 128a on the inner bearing ring 112 lifted and thus the non-touching seal.

If no compressed air is applied or the rolling bearing 110 stops, the sealing washer moves 120 preferably returns its elastic properties to its original position and lies with its sealing surface 120a at the contact surface 128a at.

The cleaning medium, which is also in the flow direction 130 on the rolling bearing 110 the sealing washer can 120 Do not open, as the cleaning agent will not apply the required pressure. As a result, penetration of detergent into the bearing is reliably prevented because the gasket 120 the bearing seals.

This condition of concern of the sealing washer 120 is in 11 shown.

Alternatively, it may be provided that the pressure of the sterilization medium is significantly greater than the pressure of the flow 130 the compressed air during operation of the dental handpiece, causing the sealing disc 120 is pressed against a second contact surface and thus seals the bearing ( 13 ).

The installation of the sealing washer 120 can be easier if the contact surface 132a for the sealing surface 120a the sealing washer 120 through a separate component 132 is formed as it is in 12 is shown.

The separate component 132 can on the inner bearing ring 112 ' be arranged after the gasket 120 is mounted. The separate element 132 can on the inner ring 112 ' be arranged and fixed by frictional connection, material connection or positive connection.

In this case, the additional element 132 be formed in its shape so that the sealing effect with respect to the sealing washer 120 is increased, for. B. by an extended contact surface between the sealing washer 120 and the additional component 132 ,

The additional element 132 but can also be optimized in its shape, so that the flow effect of the pressure medium is influenced, for. B. the flow resistance is increased and lifting the sealing washer 120 from the seal seat only when a certain minimum pressure is exceeded.

The connection between the inner ring 112 ' and the element 132 can be done for example by pressing or shrinking (adhesion) or by laser welding or gluing (fabric bond) and alternatively by screwing or a snap-in connection (positive connection).

13 shows a section through the third embodiment of the rolling bearing according to the invention 10 during the sterilization process. In 13 are the same components with the same reference numerals as in 9 and the general description of 9 ,

During a high-pressure cleaning process, a cleaning medium penetrates under high pressure in the flow direction 134 into the warehouse. The pressure of the cleaning medium is significantly higher than the pressure of the compressed air flowing through the bearing during operation of the bearing. The pressure of the cleaning medium causes the sealing washer 120 deformed beyond its intended during operation of the bearing opening position and lays down to a second contact surface 128b at. The second contact surface is the first contact surface 128a in the flow direction 134 across from. As a result, a cleaning medium acting on the bearing under high pressure does not penetrate into the interior of the rolling bearing 110 penetrate, as the sealing washer 120 together with the second contact surface 128b the bearing seals.

LIST OF REFERENCE NUMBERS

1

Dental handpiece (head housing)

2

rotor shaft

4

Rotor (turbine wheel)

6

Tool

8th

roller bearing

10, 110

roller bearing

12, 112, 112 '

inner bearing ring

12a

contact surface

14, 114

outer bearing ring

16, 116

bearing balls

18, 118

ball cage

20, 120

sealing washer

20a, 120a

sealing surface

20b

drilling

22, 122

support disc

22a

drilling

22b

deepening

23

support disc

23a

welded joint

24, 124

clamping ring

26, 126

Puncture (outer ring)

26a, 126a

guide surface

26b, 126b

sloping surface

28, 128

Puncture (inner ring)

28a, 128a

contact surface

128b

contact surface

30, 130

airflow

132

element

132a

contact surface

134

Cleaner power

Claims (20)

Rolling bearings, in particular ball bearings, with a sealing system and an outer bearing ring ( 14 ) and an inner bearing ring ( 12 ), between which rolling elements, in particular bearing balls ( 16 ), wherein the sealing system is an annular sealing disc ( 20 . 120 ) and at least one sealing disc covering the first support disk ( 22 . 122 ), wherein the sealing disc and the first support disc are arranged between the two bearing rings, and with a stationary rolling bearing a sealing surface ( 20a . 120a ) of the sealing disc ( 20 . 120 ) on a contact surface ( 12a . 28a . 128a ) is applied, characterized in that on the inner peripheral surface of the outer bearing ring ( 14 ) and / or on an outer circumferential surface of the inner bearing ring ( 12 ) Means for centering the sealing disc ( 20 . 120 ) and / or the at least one support disk ( 22 . 122 ) are provided. Rolling bearing according to claim 1, characterized in that on the inner peripheral surface of the outer bearing ring ( 14 ) a puncture ( 26 ) with a cylindrical guide surface ( 26a ) is provided, on which the sealing disc ( 20 ) and the first support disk ( 22 ) are guided radially and centered. Rolling bearing according to claim 2, characterized in that the cylindrical guide surface ( 26a ), has an axial length L which is dimensioned so that it the sealing disc ( 20 ) with an axial Length L1 and at least a portion of the first support disk ( 22 ) with an axial length L2, where L - L1 ≥ 0.5L2. Rolling bearing according to one of claims 1 to 3, characterized in that on the inner peripheral surface of the outer bearing ring ( 14 ) a puncture ( 26 ) with a cylindrical guide surface ( 26a ) is provided, on which the first support disk ( 22 ) and a second support disk ( 23 ) are radially guided and centered, wherein the sealing disc ( 20 ) on the outer peripheral surface of the inner race ( 12 ) is guided and centered. Rolling bearing according to one of claims 1 to 4, characterized in that the sealing disc ( 20 ) between the first and a second support disk ( 22 . 23 ) is arranged. Rolling bearing according to one of claims 1 to 5, characterized in that a positioning of the sealing disc ( 20 ) with respect to the at least one support disk ( 22 . 23 ) takes place during assembly of the sealing system, wherein the radial position of the sealing disc ( 20 ) with respect to the at least one support disk ( 22 . 23 ) is fixed by suitable means. Rolling bearing according to claim 6, characterized in that the means for fixing the sealing disc ( 20 ) with respect to the at least one support disk ( 22 . 23 ) a fuse element ( 24 ). Rolling bearing according to claim 7, characterized in that the securing element ( 24 ) with its outer circumference in a puncture ( 26 ) on the inner peripheral surface of the outer race ( 14 ), whereby the puncture ( 26 ) an inclined surface ( 26b ) having. Rolling bearing according to claim 8, characterized in that the oblique surface ( 26b ) of the puncture ( 26 ) has a slope of 30 ° +/- 10 ° with respect to the axis of rotation of the bearing. Rolling bearing according to one of claims 1 to 9, characterized in that the means for fixing the sealing disc ( 20 ) with respect to the at least one support disk ( 22 . 23 ) comprise an adhesive bond. Rolling bearing according to claim 10, characterized in that the first support disk ( 22 ) at least one bore ( 22a ), which up to the sealing disc ( 20 ), and into the hole ( 22a ) Adhesive is introduced, thereby fixing the sealing disc ( 20 ) with respect to the first support disk ( 22 ) he follows. Rolling bearing according to claim 10, characterized in that both the first support disc ( 22 ) as well as the sealing disc ( 20 ) at least one concentric bore ( 20b . 22a ), and in these concentric holes ( 20b . 22a ) Adhesive is introduced, thereby fixing the sealing disc ( 20 ) with respect to the first and second support disk ( 22 . 23 ) he follows. Rolling bearing according to one of claims 1 to 9, characterized in that the means for fixing the sealing disc ( 20 ) with respect to the at least one support disk ( 22 . 23 ) a welded connection ( 23a ). Rolling bearing according to claim 13, characterized in that the first support disk ( 22 ) at least one bore ( 22a ), which up to the sealing disc ( 20 ), and the sealing disc ( 20 ) in the area of the bore ( 22a ) with the first support disk ( 22 ) welded and thereby with respect to the first support disc ( 22 ) is fixed. Rolling bearing according to claim 13, characterized in that both the first support disc ( 22 ) as well as the sealing disc ( 20 ) at least one concentric bore ( 20b . 22a ), and the support discs ( 22 . 23 ) welded in the region of the holes and the sealing disc ( 20 ) thereby with respect to the support discs ( 22 . 23 ) is fixed. Rolling bearing according to claim 13, characterized in that a first support disk ( 22 ) has at least one bead-shaped recess which in at least one associated bore ( 20b ) of the sealing disc ( 20 ) engages and up to the second support disc ( 23 ), the support discs ( 22 . 23 ) in the area of the depression ( 22b ) are welded together and the sealing disc ( 20 ) is thereby fixed with respect to the two support disks. Rolling bearing according to one of claims 1 to 16, characterized in that the rolling bearing ( 10 . 110 ) is flowed through during operation of a medium, wherein the sealing surface ( 20a . 120a ) of the sealing disc ( 20 . 120 ) by the flowing medium from its bearing surface ( 12a . 28a . 128a ) is lifted, wherein the sealing system is arranged on the flow direction of the medium-facing side of the rolling bearing. Rolling bearing according to claim 17, characterized in that the contact surface ( 132a ) for the sealing disc ( 120 ) by a separate annular component ( 132 ) is formed, which after mounting the gasket ( 120 ) on the inner bearing ring ( 112 ) is mounted. Rolling bearing according to one of claims 1 to 18, characterized in that in the case of an impinging on the sealing system of the rolling bearing fluid ( 134 ) whose pressure is significantly greater than the pressure of the medium flowing through during operation of the rolling bearing ( 130 ), the sealing surface ( 120a ) of the sealing disc ( 120 ) from its first contact surface ( 128a ) and to a second contact surface ( 128b ) is pressed and so the interior of the bearing against the impinging fluid ( 134 ) seals. Dental Hand Instrument ( 1 ), which at least one rolling bearing ( 10 . 110 ) according to one or more of claims 1 to 18.

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