DE102015114889A1 - Internal clamping screw - Google Patents

Abstract

The present invention relates to an inner clamping screw (100) having an inner recess (103) for inserting a component (105) and at least two threaded tongues (107-1, ..., 107-4) with an outer thread (109) around the inner recess (103) are arranged for clamping the component (105). The external thread (109) is a buttress thread which has a load-bearing thread flank with a partial flank angle of more than 30 ° to 80 °.

Description

The present invention relates to an inner clamping screw with an inner recess for clamping and fixing an inserted component.

An inner clamping screw is a hollow screw with a cylindrical inner diameter and a metric outer thread on the outer diameter. The external thread is slotted axially, so that a plurality of threaded tongues arise, which have a radial elasticity. After introducing a cylindrical shaft corresponding diameter in the inner clamping screw, the external thread of the inner clamping screw is screwed into a hub member which is provided with a corresponding internal thread.

The publication DE 25 18 382 relates to a saw thread clamping sleeve with associated clamping body. With such a clamping unit workpieces are to be firmly recorded in their holes to edit them by over-turning, grinding or another type of production.

The publication DE 20 2005 003 812 U1 relates to a clamping sleeve for releasably supporting a tubular or rod-shaped component on a through-threaded hole having carrier, beam or tube.

The publication EP 0 251 016 A1 relates to a device for clamping a machine element in a part which is connected to the machine element, by means of a clamping sleeve.

The publication EP 1 856 418 B1 relates to a clamping sleeve for releasably supporting a longitudinally extended component of constant cross-section.

When tightening the screw connection, radial force components are produced on the threaded tongues via the flank angles of the external thread, which effect a fixation of the inserted shaft in the hub component. The inner clamping screw is typically well suited for fixing objects on cylindrical shafts under static axial loading or low torsional loading. For a torque transmission of toothed belt pulleys of a parallel kit with changing direction of rotation, however, the achieved clamping action of this inner clamping screw is too low.

It is therefore the object underlying the invention to improve the clamping action of an inner clamping screw.

This object is achieved by objects according to the independent claims. Advantageous embodiments are the subject of the dependent claims, the description and the figures.

According to a first aspect, the object is achieved by an inner clamping screw, with an inner recess for inserting a component and at least two threaded tongues with an external thread, which are arranged around the inner recess, for clamping the component. The external thread is a buttress thread, which has a load-bearing thread flank with a partial flank angle of over 30 ° to 80 °. As a result, the advantage is achieved that a high torque transmission is possible with a low tightening torque. This is achieved by the special shape of the saw thread, in which the thread flank contacting when tightening the screw has a flat contact surface. The partial flank angle of the supporting thread flank is for example preferably in the range of 50 ° to 70 °.

In an advantageous embodiment of the inner clamping screw, the external thread has a non-load thread flank with a partial flank angle of less than 5 °. As a result, for example, the technical advantage is achieved that the thread pitch remains small and thus a high degree of self-locking of the thread is achieved. The partial flank angle of the non-load thread flank is for example preferably in the range of 2 ° to 4 °.

In a further advantageous embodiment of the inner clamping screw, the external thread has a fine thread pitch. As a result, the technical advantage is achieved, for example, that when tightening the inner clamping screw clamping action can be increased slowly and well dosed and better self-locking is achieved with reversing torque transmission. The fine pitch is a pitch that is less than a pitch. Standard thread and their Regelgewindesteigungen are in the DIN 13-1 Are defined.

In a further advantageous embodiment of the inner clamping screw, the external thread has a sliding coating. As a result, for example, the technical advantage is achieved that the Gewindibibwert is reduced, so that a higher proportion of the tightening torque is used to generate the clamping force.

In a further advantageous embodiment of the inner clamping screw, the inner clamping screw comprises an even number of threaded tongues. As a result, for example, the technical advantage is achieved that the inner clamping screw manufacturing technology can be produced with little effort.

In a further advantageous embodiment of the inner clamping screw, the inner clamping screw comprises a screw head with a hexagon socket, a hexalobular profile or an external hexagon profile. The external hexagonal profile, for example, achieves the technical advantage that the inner clamping screw can also be mounted on shafts that project beyond the screw head. The hexagon socket or hexalobular profile achieves, for example, the technical advantage that the inner clamping screw can be mounted more easily on short shaft ends which do not protrude into the screw head.

In a further advantageous embodiment of the inner clamping screw, the external thread is a conical thread. As a result, for example, the technical advantage is achieved that the increased clamping effect is achieved using a standardized thread geometry.

In a further advantageous embodiment of the inner clamping screw, the threaded tongues are separated by axial slots. As a result, for example, the technical advantage is achieved that the threaded tongues have a radial elasticity.

In a further advantageous embodiment of the inner clamping screw, the axial slots extend from the tip of the threaded tongues to the screw head. As a result, for example, the technical advantage is achieved that a high elasticity of the threaded tongues is realized.

In a further advantageous embodiment of the inner clamping screw, the inner recess has a cylindrical shape. Thereby, for example, the technical advantage is achieved that a hub component for transmitting torque, i. a clutch, a gear or a toothed pulley, can be mounted on a cylindrical shaft by the inner clamping screw.

In a further advantageous embodiment of the inner clamping screw, the inner clamping screw on a neck-shaped taper between the screw head and external thread. As a result, the technical advantage is achieved, for example, that with an external thread and various internal bores, the attachment of a hub component on different shaft diameters is made possible without the elasticity of the thread tongues changed significantly.

In a further advantageous embodiment of the inner clamping screw, the inner clamping screw has one or more cylindrical shoulders for centering in a hub component. The cylindrical shoulder is preferably arranged below the screw head or at the threaded end. As a result, for example, the technical advantage is achieved that the radial concentricity of a hub member on the shaft can be improved.

According to a second aspect, the object is achieved by an inner clamping screw, with an inner recess for inserting a component and at least two threaded tongues with an external thread, which are arranged around the inner recess, for clamping the component. The external thread is a tapered thread. As a result, the technical advantage is achieved that the increased clamping effect is achieved using a standardized thread geometry. The inner clamping screw can thereby also be formed without stopping the head support surface in an even shorter axial design. The further the inner clamping screw is screwed in, the higher the clamping effect on the component. The inner clamping screw according to the second aspect represents an alternative solution for the above-mentioned task.

In an advantageous embodiment of the inner clamping screw, the external thread is a saw thread, which has a load-bearing thread flank with a partial flank angle of more than 30 ° to 80 °. As a result, for example, the technical advantage is achieved that the clamping action of the inner clamping screw is further improved.

In a further advantageous embodiment of the inner clamping screw, the external thread has a non-load thread flank with a partial flank angle of less than 5 °. As a result, for example, the technical advantage is achieved that the thread pitch remains small and thus a high self-locking of the thread is achieved.

In a further advantageous embodiment of the inner clamping screw, the external thread has a fine thread pitch. As a result, for example, the technical advantage is achieved that when tightening the inner clamping screw clamping action can be increased slowly and well dosed and better self-locking is achieved with reversing torque transmission.

In a further advantageous embodiment of the inner clamping screw, the inner clamping screw comprises an even number of threaded tongues. As a result, for example, the technical advantage is also achieved that the inner clamping screw can be manufactured manufacturing technology with little effort.

In a further advantageous embodiment of the inner clamping screw, the Inner clamping screw has a neck-shaped taper between the screw head and the external thread. As a result, the technical advantage is achieved, for example, that with an external thread and various inner holes, the attachment of a hub component on different shaft diameters is made possible without changing the elasticity of the thread tongues significantly.

In a further advantageous embodiment of the inner clamping screw, the inner clamping screw has one or more cylindrical shoulders for centering in a hub component. As a result, for example, the technical advantage is achieved that the radial concentricity of a hub member on the shaft can be improved.

According to a third aspect, the object is achieved by a hub component, having a recess with an internal thread for screwing in an inner clamping screw according to the first aspect. The internal thread is a saw thread, which has a load-bearing thread flank with a partial flank angle of over 30 ° to 80 °. In general, the internal thread is formed corresponding to the external thread of the inner clamping screw. This achieves the same technical advantages as the inner clamping screw according to the first aspect.

Embodiments of the invention are illustrated in the drawings and will be described in more detail below.

Show it:

1 a perspective view of an inner clamping screw;

2 a cross-sectional view of the inner clamping screw;

3 a cross-sectional view of an external thread; and

4 a perspective view and a cross-sectional view of the inner clamping screw with Zentrierabsatz.

1 shows a perspective view of an inner clamping screw 100 , The inner clamping screw 100 is for example made of steel. The inner clamping screw 100 includes a cylindrical inner recess 103 for inserting a cylindrical component 105 whose outer diameter is the inner diameter of the inner recess 103 equivalent. The cylindrical component 105 is a wave, for example.

In general, the interior recess 103 also have a different shape, so that even components with non-cylindrical cross-sections through the inner clamping screw 100 can be clamped and secured, such as in the cross section square or hexagonal components.

Next comprises the inner clamping screw 100 four quarter-circle-shaped thread tongues in cross-section 107-1 , ..., 107-4 , The thread tongues 107-1 , ..., 107-4 together have a cylindrical outer circumference, with an external thread 109 is provided. An even number of threaded tongues is advantageous in terms of production, in general, the number of threaded tongues 107 be arbitrary, such as two, three, five or six. The external thread 109 is a profiled notch, which is continuously helical around the cylindrical wall of the threaded tongues 107-1 , ..., 107-4 runs in a helix. The external thread 109 can be a right-hand or left-hand thread.

The thread tongues 107-1 , ..., 107-4 are around the cylindrical interior recess 103 arranged around. The thread tongues 107-1 , ..., 107-4 are longitudinally through an axial slot 117 separated, extending from the top of the threaded tongues 107-1 , ..., 107-4 to the screw head 113 extends. The screw head 113 is one-piece with the thread tongues 107-1 , ..., 107-4 connected.

The thread tongues 107-1 , ..., 107-4 have elasticity in the radial direction. Will the inner clamping screw 100 with the external thread 109 screwed into a hub member, which is provided with a corresponding internal thread, the threaded tongues 107-1 , ..., 107-4 pressed radially inward and thereby fix the component 105 in the interior recess 103 ,

2 shows a cross-sectional view of the inner clamping screw 100 , The cylindrical screw head 113 has a hexagon socket 115 as a screw head drive for turning the inner clamping screw 100 on. The component 105 gets into the cylindrical inner recess 103 plugged and through the thread tongues 107-1 , ..., 107-4 when screwing in the inner clamping screw 100 in the internal thread 121 a hub component 123 in a cylindrical recess 125 is arranged, fixed. The internal thread 121 of the hub component 123 is also a saw thread, which has a load-bearing thread flank with a corresponding partial flank angle of 60 ° and a non-load thread flank with a partial flank angle of 3 °.

Between the external thread 109 and the screw head 113 include the threaded tongues 107-1 , ..., 107-4 a neck-shaped rejuvenation 119 . which forms a threadless intermediate section. The neck-shaped rejuvenation 119 has a smaller diameter than the threaded tongues 107-1 , ..., 107-4 in the area of the external thread 109 on. Due to the smaller thickness in the area of the neck-shaped rejuvenation 119 can the elasticity of the thread tongues 107-1 , ..., 107-4 be improved.

3 shows a flank profile of the external thread 109 , The external thread 109 is a saw thread, which is a bearing thread flank 111-1 with a partial flank angle of 60 ° and a non-load thread flank 111-2 having a partial edge angle of 3 °. The partial flank angle is the angle between a radial coordinate axis perpendicular to the central axis of the screw and one of the two flank lines of the thread profile.

The saw thread is due to its asymmetrical profile for generating high radial clamping forces. Due to the large partial flank angle of 60 °, the axial preload force when tightening the inner clamping screw 100 converted to a larger proportion in radial clamping forces than a standard thread with partial flank angle 30 °.

This allows the principle of the inner clamping screw 100 be optimized so far that the highest possible torque transmission is possible with the lowest possible tightening torque. This is achieved by the special shape of the saw thread, in which when tightening the inner clamping screw 100 in contact standing thread flank 111-1 represents a flat as possible contact surface.

To maintain the self-locking of the thread, the pitch angle of the external thread 109 kept small, preferably a fine thread pitch is provided. The fine pitch is a pitch that is less than a pitch. The when tightening the inner clamping screw 100 non-contacting thread flank 111-2 has a steep flank drop with a partial flank angle of 3 °.

In another embodiment, on the outer diameter of the inner clamping screw a conical pipe thread (eg R-thread, see DIN EN 10226 ), while at the inner diameter of a hub, not shown, a cylindrical pipe thread (G-thread, see DIN EN 10226 ). The cone geometry of the external thread 109 causes a similar clamping force enhancing effect as the enlarged partial flank angle 111-1 at the saw thread. With a similar clamping effect standardized thread geometries can be used in this case.

This inner clamping screw can otherwise the same features as the inner clamping screw shown 100 exhibit. This internal clamping screw with the conical pipe thread represents an alternative solution for the task to improve the clamping action of an inner clamping screw.

Regardless of the chosen thread geometry, a sliding coating of the external thread can be used in all cases 109 to be provided. For example, the external thread 109 have a thread coating with a wax, polytetrafluoroethylene (PTFE) or molybdenum disulfide (MoS ₂ ) coating.

4 shows a perspective view and a cross-sectional view of the inner clamping screw 100 with a cylindrical heel 127 , The cylindrical paragraph 127 is equipped with a fitting tolerance for centering in a hub member and is in a corresponding diameter in the recess 125 of the hub component 123 introduced. In general, several such cylindrical paragraphs 127 in the inner clamping screw 100 be provided. The cylindrical heel 127 causes the radial runout of a hub member on the shaft is improved.

The principle of the inner clamping screw 100 represents an easy to install alternative to conventional cone-clamping elements as a shaft-hub connection. In particular, the small radial space requirement, which allows small-sized shaft-hub connections is advantageous. Due to the optimized thread profile, a high proportion of the tightening torque can be used for torque transmission.

All of the features explained and shown in connection with individual embodiments of the invention may be provided in different combinations in the article according to the invention in order to simultaneously realize their advantageous effects.

The scope of the present invention is given by the claims and is not limited by the features illustrated in the specification or shown in the figures.

LIST OF REFERENCE NUMBERS

100

 Internal clamping screw

103

 indoor recess

105

 component

107

 thread tongues

109

 external thread

111

 thread flank

113

 screw head

115

 Allen Profile

117

 slot

119

 neck-shaped rejuvenation

121

 inner thread

123

 hub component

125

 recess

127

 cylindrical heel

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 2518382 [0003]
• DE 202005003812 U1 [0004]
• EP 0251016 A1 [0005]
• EP 1856418 B1 [0006]

Cited non-patent literature

• DIN 13-1 [0012]
• DIN EN 10226 [0047]
• DIN EN 10226 [0047]

Claims (20)

Inner clamping screw ( 100 ), with: an interior recess ( 103 ) for inserting a component ( 105 ); and at least two threaded tongues ( 107-1 , ..., 107-4 ) with an external thread ( 109 ) around the inner recess ( 103 ) are arranged, for clamping the component ( 105 ); characterized in that the external thread ( 109 ) is a saw thread, which has a load-bearing thread flank ( 111-1 ) having a partial flank angle of about 30 ° to 80 °. Inner clamping screw ( 100 ) according to claim 1, characterized in that the external thread ( 109 ) a non-load thread flank ( 111-2 ) having a partial flank angle of less than 5 °. Inner clamping screw ( 100 ) according to one of the preceding claims, characterized in that the external thread ( 109 ) has a fine pitch. Inner clamping screw ( 100 ) according to one of the preceding claims, characterized in that the external thread ( 109 ) has a lubricious coating. Inner clamping screw ( 100 ) according to one of the preceding claims, characterized in that the inner clamping screw ( 100 ) an even number of threaded tongues ( 107-1 , ..., 107-4 ). Inner clamping screw ( 100 ) according to one of the preceding claims, characterized in that the inner clamping screw ( 100 ) a screw head ( 113 ) with a hexagon profile ( 115 ), a hexalobular profile or an external hexagon profile. Inner clamping screw ( 100 ) according to one of the preceding claims, characterized in that the external thread ( 109 ) is a tapered thread. Inner clamping screw ( 100 ) according to one of the preceding claims, characterized in that the threaded tongues ( 107-1 , ..., 107-4 ) through axial slots ( 117 ) are separated. Inner clamping screw ( 100 ) according to claim 8, characterized in that the axial slots ( 117 ) from the tip of the threaded tongues ( 107-1 , ..., 107-4 ) to the screw head ( 113 ). Inner clamping screw ( 100 ) according to one of the preceding claims, characterized in that the inner recess ( 103 ) has a cylindrical shape. Inner clamping screw ( 100 ) according to one of the preceding claims, characterized in that the inner clamping screw ( 119 ) a neck-shaped rejuvenation ( 119 ) between screw head ( 113 ) and external thread ( 109 ) having. Inner clamping screw ( 100 ) according to one of the preceding claims, characterized in that the inner clamping screw ( 100 ) one or more cylindrical paragraphs ( 127 ) for centering in a hub component ( 123 ) having. Inner clamping screw ( 100 ), with: an interior recess ( 103 ) for inserting a component ( 105 ); at least two threaded tongues ( 107-1 , ..., 107-4 ) with an external thread ( 109 ) around the inner recess ( 103 ) are arranged, for clamping the component ( 105 ); characterized in that the external thread ( 109 ) is a tapered thread. Inner clamping screw ( 100 ) according to claim 13, characterized in that the external thread ( 109 ) is a saw thread, which has a load-bearing thread flank ( 111-1 ) having a partial flank angle of about 30 ° to 80 °. Inner clamping screw ( 100 ) according to claim 13 or 14, characterized in that the external thread ( 109 ) a non-load thread flank ( 111-2 ) having a partial flank angle of less than 5 °. Inner clamping screw ( 100 ) according to one of claims 13 to 15, characterized in that the external thread ( 109 ) has a fine pitch. Inner clamping screw ( 100 ) according to one of claims 13 to 16, characterized in that the inner clamping screw ( 100 ) an even number of threaded tongues ( 107-1 , ..., 107-4 ). Inner clamping screw ( 100 ) according to one of claims 13 to 17, characterized in that the inner clamping screw ( 100 ) a neck-shaped rejuvenation ( 119 ) between the screw head ( 113 ) and the external thread ( 109 ) having. Inner clamping screw ( 100 ) according to one of claims 13 to 18, characterized in that the inner clamping screw ( 100 ) one or more cylindrical paragraphs ( 127 ) for centering in a hub component ( 123 ) having. Hub component ( 123 ), With: a recess ( 125 ) with an internal thread ( 121 ) for screwing in an inner clamping screw ( 100 ) according to any one of claims 1 to 12; characterized in that the internal thread ( 121 ) is a saw thread, which has a load-bearing thread flank ( 111-1 ) having a partial flank angle of about 30 ° to 80 °.

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