Components for connecting the clamp holder to the shaft

Abstract

In a component (1) for connecting a shaft to a clamp holder (6) capable of receiving a rotor, the clamp holder can be inserted into a cup-shaped housing (2) and secured therein by fastening means (13). A housing base (3) of the housing (2) has connecting means (7) for connecting the housing (2) to the shaft so that they rotate together. The fastening means (13) has its base surface (17) located on the outer surface (12) of the housing (2) and can engage with the clamp holder (6) through a bore present in the housing (2). The fastening means (13) has at least one recess (18) in the base surface (17) so that it is aligned with the base surface (17) on the outer surface (12) only in a partial area.

Description

[Technical Field]

[0001] The present invention relates to a component for connecting a shaft to a clamping holder capable of receiving a rotor, the component having a cup-shaped thin-walled housing into which the clamping holder can be inserted and which can be fixed therein by fastening means. [Background technology]

[0002] Rotating test benches are used to measure the loads acting on rotating bodies. In these test benches, rotating bodies such as rotors are operated at and beyond their operating speed range. Furthermore, the rotors may be subjected to, for example, periodic rotational speed changes or temperature fluctuations. In this case, the rotors may be accelerated, for example, by fastening them to a thin elastic shaft via their shaft journals. For this reason, the rotors must be able to be easily fastened and unclamped to the spin shaft.

[0003] Known rotor clamp holders have centrifugal segments to compensate for the effects of centrifugal forces acting on the clamp of the rotor.

[0004] DE 15 52 197 C discloses a centrifugal chuck for high-speed tools, having a plurality of chuck jaws that together form a chuck jaw ring. This centrifugal chuck has flyweights formed with the chuck jaws, which are pivotable around a lever pivot point as a two-arm lever. The flyweights are arranged between two chuck jaw rings that are axially spaced apart from each other and each flyweight is integrally formed with one of the chuck jaws of the two chuck jaw rings. In this case, the chuck jaw rings project radially outward between their ends to form the lever pivot point.

[0005] US 2 830 822 A discloses a centrifugal chuck in which a plurality of weights are arranged around a rotor and move radially outward as a result of centrifugal force when the rotor rotates. The weights are further connected to a ring, which is connected to claws arranged on the rotor to allow radial movement. As a result of the radially outward movement of the weights as a result of centrifugal force, the parts of the ring connected to the weights are also moved outward, and the claws connected to the parts of the ring between them are attracted towards each other.

[0006] DE 42 20 136 C1 discloses a clamping system for a machine tool for clamping a rotatably oriented tool and / or workpiece, the system having a chuck or base body, a clamping mechanism, base jaws, and attachment jaws. In this case, the attachment jaws are at least partially made of fiber-reinforced plastic, while the chuck body, clamping mechanism, base jaws, and the joints between the base jaws and attachment jaws are made of metal. A centrifugal balance weight is disposed on the fiber-reinforced plastic joint between the clamping elements and is radially movable with the fiber-reinforced plastic joint but fixed in the tangential direction. As the rotational speed increases, and thus the centrifugal force increases outward, the fiber-reinforced plastic joint is displaced outward. Because the joint is made of high-rigidity carbon fiber, only slight expansion occurs, and the radial tension acting on the clamping block and workpiece increases outward due to the deformation of the fiber-reinforced plastic joint.

[0007] Furthermore, DE 198 34 739 C1 describes a clamping device in which a polygonal base body is elastically rounded. In this case, the area of ​​the base body located between the force application points is deformed so that the holder expands and a round shaft can be inserted. As soon as the radial force acting on the base body is reduced or removed, the base body returns to its original polygonal shape due to its elastic properties, and the shaft is fixed in the receptacle. EP 1 669 621 B1 develops from this teaching by inserting a centrifugal compensation weight into a cavity in the base body so that the centrifugal force generated pushes the centrifugal compensation weight outward. As a result, the area between the two points bends inward, increasing the clamping force acting on the shank.

[0008] Components are provided to connect the rotor held in the clamp holder to the shaft, transmitting weight forces from the rotor to the spin shaft and transmitting drive torque from the shaft to the rotor.

[0009] DE 195 21 755 C1 describes a connection system intended for repeatedly and fixedly connecting two components, in which one component is temporarily deformed during the connection process so that its effective circumferential contour corresponds to the corresponding effective circumferential contour of the other component with a predefined clearance, and after the positioning process of both components, a fixed contact pressure of the two effective circumferential contours acts by at least partial return deformation.

[0010] Furthermore, DE 196 24 048 A1 discloses a friction connection between two components.

[0011] DE 907 233 B describes a variable diameter tubular workpiece holder for machine tools, which has clamping surfaces that protrude beyond the diameter of the part to be received and extend only over a portion of its circumference, and which can be adjusted to the diameter of the workpiece by causing elastic deformation of the area of ​​the holder between them.

[0012] A problem with known components for receiving clamp holders is that forces are exerted on the clamp holder by the clamp, which can result in inaccurate measurements, especially in the case of clamp holders with centrifugal force compensation, which can affect the concentricity properties of the clamp holder. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] German Patent No. 1552197C [Patent Document 2] U.S. Patent No. 2,830,822A [Patent Document 3] German Patent No. 4220136C1 [Patent Document 4] German Patent No. 19834739C1 [Patent Document 5] European Patent No. 1669621B1 [Patent Document 6] German Patent No. 19521755C1 [Patent Document 7] German Patent No. 19624048A1 [Patent Document 8] German Patent No. 907233B Summary of the Invention [Problem to be solved by the invention]

[0014] SUMMARY OF THE INVENTION The present invention aims to provide an apparatus for receiving a rotor clamp holder in which the clamping of the rotor is not compromised by the clamp holder. [Means for solving the problem]

[0015] This object is achieved by the features of claim 1. Preferred embodiments are set forth in the dependent claims.

[0016] According to the present invention, this object is achieved by providing a component for connecting a shaft to a clamping holder capable of receiving a rotor, the component having a cup-shaped, thin-walled housing into which the clamping holder can be inserted and secured therein by fastening means, and a housing base of the housing having connecting means for connecting the housing to the shaft so as to rotate together with the housing, the fastening means having a base surface arranged on the outer surface of the housing and capable of engaging with the clamping holder through a bore present in the housing, and having at least one recess in the base surface so that the base surface rests only in a partial area on the outer surface, thus preventing deformation of the housing, particularly when the clamping holder is secured in the housing. An advantage of the present invention is that the clamping holder capable of receiving a rotor can be positioned in the cup-shaped housing in a defined manner, and furthermore, the method of fastening the clamping holder according to the present invention prevents forced deformation of the housing, which would likely also exert forces on the clamping holder and thereby affect the clamping or release process of the rotor. Furthermore, the concentricity properties of the clamping holder are not impaired. The component according to the present invention has proven particularly advantageous for clamping holders with centrifugal force compensation. The component according to the invention with this feature ensures, on the one hand, a stable connection of the clamp holder and a rigid transmission of forces and torques without play. On the other hand, the housing has a certain radial flexibility due to its thin-walled design, which does not affect the clamp holder, or more precisely its centrifugal force components, which compensate for the centrifugal forces. Furthermore, expansion of the clamp holder, for example due to the action of external forces on the clamp holder or the housing, is also possible.

[0017] In one embodiment, the fastening means comprises a clamping block and a screw, the clamping block having at least one recess in its base surface. A preferred fastening is achieved in that the screw is screwed through a corresponding bore in the outer surface of the clamping block or the housing into a corresponding bore in the clamping holder. In this case, the clamping block is pressed against the outer surface by the screw, and the base surface of the clamping block is stationary relative to the outer surface of the housing. Due to the fact that the fastening means, in particular the clamping block, has a recess in its base surface, two linear contacts in particular are created between the base surface of the clamping block and the outer side surface, which evenly distributes the forces acting on the housing and prevents deformation of the housing.

[0018] Preferably, each clamping block has at least one through-hole for a screw, and the base surface of the clamping block is cut out in the area of ​​the through-hole. Depending on the application, one or more through-holes for the passage of a screw or screws are provided in one clamping block. A recess is particularly present in the area of ​​the base surface of the clamping block where the through-hole opens, and this recess has a diameter greater than the diameter of the through-hole. The recess can be milled, for example, so that there is a gap between the through-hole and the outer surface.

[0019] In one embodiment, the clamping block has a rectangular shape and is arranged on the outer surface so that its longitudinal axis is coaxial with the longitudinal axis of the housing. Although a rectangular shape of the clamping block has been found to be advantageous, other shapes are also possible, such as rounded or polygonal clamping blocks. A clamping block designed in this way has a corresponding recess in its base surface, so that the base surface is on the outer surface only in some areas.

[0020] It has been found to be advantageous for the recess in the base surface to extend along the longitudinal axis over the entire length of the clamping block and have a width greater than the diameter of the through-hole. Thus, the recess may extend over the entire length and / or width of the clamping block, depending on the design of the clamping block. The width of the recess may depend on the shape of the clamping block, and the base surface of the clamping block is preferably truncated at least in the region of the through-hole.

[0021] Depending on the rotor weight and / or the desired rotation speed, it may be advantageous for the clamping block to have multiple through-holes along the longitudinal axis, which allows for a secure, high-load-bearing connection between the component and the clamping holder. The fastening of the clamping holder on the component can be adapted to the type of rotor to be received by the clamping holder and / or the desired rotation speed, and in certain applications it may be sufficient for the component to have at least three fastening means arranged at a distance from each other on its outer surface. In certain applications, more than three fastening means arranged on the outer surface may also be provided accordingly.

[0022] The housing has a connecting means on its housing base for connecting the housing to the shaft so as to rotate together. The connecting means can be, for example, a receptacle or recess into which a corresponding connecting means on the shaft can be connected. The connecting means on the shaft can be fastened by a screw to a corresponding receptacle or recess on the housing base.

[0023] In one embodiment, the housing is a thin-walled cup that has a certain radial flexibility and therefore does not impair the centrifugal force compensation or the clamping process of the clamp holder. The shape of the thin-walled cup also has a sufficiently high torsional rigidity. In particular, it is advantageous for the wall thickness of the housing to be between 0.3 mm and 3 mm. This range of wall thickness has been shown to provide, firstly, sufficient stability and, secondly, sufficient flexibility.

[0024] To establish sufficient contact between the base surface of the clamping block and the exterior surface of the housing, in preferred embodiments, the base surface of the clamping block may be formed to be concave or flat.

[0025] The invention will be explained in more detail below with reference to embodiments shown in the drawings. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 12 is a perspective view of a cup-shaped component having an integral clamp holder. [Figure 2] 2 is a longitudinal section through the component according to FIG. 1; [Figure 3] FIG. 2 is an enlarged view of a clamp block. DETAILED DESCRIPTION OF THE INVENTION

[0027] Figure 1 is a perspective view of a cup-shaped component with an integrated clamp holder, Figure 2 is a longitudinal section of the component according to Figure 1, and Figure 3 is an enlarged view of the clamp block. The cup-shaped component 1 has a hollow cylindrical housing 2 with a housing base 3, which together with its outer surface 4 forms a space 5 for receiving a clamp holder 6. The clamp holder 6 can be inserted in a simple manner through the open side of the housing 2. The outer surface 4 of the housing 2 is thin-walled and can consist, for example, of a metal sheet, so that the component 1 is lightweight and can also have high torsional stiffness.

[0028] Connection means 7 are provided in the housing base 3, by means of which the component 1 can be connected to a rotary drive. This connection can be produced, for example, by screwing a flange connection of a shaft designed as a connection means and connected to the drive into a corresponding connection means 7 designed as a receptacle or recess in the housing base 3 so as to rotate together. Such a shaft can be, for example, a thin elastic spin shaft that is attached to a spin test stand to drive a rotor.

[0029] The clamp holder 6 shown as an example has a central recess 8 for the rotor or rotor journal. The illustrated clamp holder 6 is a centrifugal force-compensating clamp holder 6 in which centrifugal segments 9 expand outward, pressing clamping segments 11 inward via leaf springs 10 to clamp the rotor. The rotor can be unclamped by applying a force from the outside to the centrifugal segments 9 in the direction of the recess 8, which causes the clamping segments 11 to move outward via the leaf springs 10. This is merely one example of a clamp holder, as components according to the present invention are provided for clamp holders of several different designs, where interference with the unclamping or clamping process by components housing the clamp holder is to be prevented. This component is particularly suitable for centrifugal force-compensating clamp holders.

[0030] To secure the clamp holder 6 in the housing 2, fastening means 13 are arranged at a distance from each other on the outer surface 12. In the illustrated example, the fastening means 13 are arranged near the open cup end so that the center of gravity of the component 1 is at a small distance from the clamping plane. The fastening means 13 can comprise a screw 14 and a clamping block 15. The screw 14 protrudes through a through-hole 16 in the clamping block 15 and a corresponding bore in the housing, and engages with a corresponding bore in the clamp holder 6. For this purpose, depending on the design of the clamp holder 6, bores can be provided at different positions in the housing 2 and the clamp holder 6. Depending on the design of the clamp holder 6, the screw head can rest on the surface of the clamping block 15 or can be countersunk in the clamping block 15. In the illustrated embodiment, the clamp holder 6 has three distal segments 9 and three clamping segments 11, each of which can be provided with one fastening means 13 for fastening. This means that each segment 9, 11 is fastened specifically to the housing 2.

[0031] In the illustrated example, the clamping blocks 15 are rectangular in design, with their longitudinal axes coaxial with the longitudinal axis of the housing 2. Two through holes 16 are arranged along the longitudinal axis of each clamping block 15, through which two screws 14 protrude. Depending on the type of rotor or the desired rotation speed, a greater or lesser number of screws 14 can be used. Clamping blocks with only one bore are also possible. In the illustrated example, six clamping blocks 15 are arranged on the outer surface 12 of the housing 2, but depending on the clamp holder, a greater or lesser number of clamping blocks 15 can be used. Screws 14 of different lengths can be used to fasten the centrifugal segments 9 and / or clamping segments 11 to the housing 2. In the illustrated embodiment, for example, the centrifugal segments 9 are fastened with longer screws 14 than the clamping segments 11. However, this can vary depending on the design of the clamp holder 6.

[0032] The clamping block 15 has a base surface 17 on the outer surface 12 of the housing 2, which is provided with at least one recess 18, as shown in FIG. 3 . Depending on the configuration of the clamping block 15, i.e., depending on the number of through-holes 16 it has, it is possible for there to be only one recess 18 in the base surface 17. Preferably, the base surface 17 has such a recess 18 that, in the region where the through-hole 16 opens, there is a gap between the through-hole 16 and the outer surface 12. The recess 18 of the clamping block 15 can extend over the entire base surface 17 in the direction of its longitudinal axis, the width of the recess 18 corresponding at least to the diameter of the through-hole 16. The recess 18 advantageously has a constant height and / or depth.

[0033] To secure the clamping holder 6 to the component 1, the screw 14 is screwed into the clamping holder 6 accommodated in the housing 2 via the clamping block 15, thereby pressing the clamping block 15 against the outer surface 12 of the housing 2. The base surface 17 of the clamping block 15 is concave, particularly in the center, so that two linear contacts occur between the clamping block 15 and the outer surface 12, and the clamping block 15 rests on the outer surface 12 of the housing 2 only in certain areas. The clamping block 15 therefore contacts the outer surface 12 along its edges but not in the area of ​​the through-hole 16. As a result, the cup-shaped housing 2 is not forced to deform, which would otherwise apply binding forces to the clamping holder 6 and reduce the concentricity accuracy of the clamping holder 6. Furthermore, the component 1, together with the clamping holder 6, has a high area moment of inertia in all spatial directions, ensuring high rigidity and, consequently, a well-defined position of the clamping holder 6.

[0034] A further advantage of the present invention is, inter alia, that a high torsional stiffness is achieved by the geometry of component 1, even though component 1 also has radial flexibility due to its thin-walled design which does not adversely affect clamp holder 6 but rather allows a certain radial movement of clamp holder 8. As a result, the effect of centrifugal forces on clamp holder 8 is not adversely affected and the rotor and / or rotor journal is reliably clamped.

[0035] The component 1 according to the invention is elastic in the radial direction, whereas the clamp holder 6 can be rigidly connected in all required spatial / angular directions by the fastening means 13 according to the invention. In particular, it has been shown that the component 1 advantageously allows the following movements of the clamp holder 8: The center of gravity of the centrifugal segment 9 is pushed outwards by the centrifugal force, so that the clamping force increases with increasing rotational speed. For unclamping, the component 1 and thus the clamp holder 8 are deformed by an external force, releasing the internal clamp and allowing the clamped rotor to be removed. After the clamping process, the component 1 can be deformed to its original shape again and has high concentricity. [Explanation of symbols]

[0036] 1. Components 2. Housing 3 Housing Base 4 External surface 5 Space 6 Clamp holder 9 Centrifugal Segment 10 Leaf springs 11 Clamp Segments

Claims

1. A component (1) for connecting a shaft to a clamping holder (6) capable of receiving a rotor, said component comprising: a cup-shaped thin-walled housing (2) into which the clamp holder (6) can be inserted and fixed therein by a fastening means (13); A housing base (3) of the housing (2) has a connecting means (7) for connecting the housing (2) to the shaft so as to rotate together with the housing (2), The fastening means (13) has its base surface (17) arranged on the outer surface (12) of the housing (2) and is engageable with the clamp holder (6) by a bore present in the housing (2), and has at least one recess (18) in the base surface (17) so that the base surface (17) rests on the outer surface (12) only in a partial area.

2. Component (1) according to claim 1, characterized in that the fastening means (13) comprise a clamping block (15) and a screw (14), the clamping block (15) having the at least one recess (18) in a base surface (17).

3. 3. The component (1) according to claim 2, characterized in that each clamping block (15) has at least one through hole (16) for the screw (14), said through hole (16) opening into said recess (18) in said base surface (17).

4. Component (1) according to claim 3, characterized in that said recesses (18) each have a diameter greater than the diameter of said through-holes (16).

5. Component (1) according to claim 2, characterized in that the clamping block (15) has a rectangular shape and is arranged on the outer surface (12) so that its longitudinal axis is coaxial with the longitudinal axis of the housing (2).

6. 4. The component (1) according to claim 3, characterized in that the recess (18) in the base surface (17) extends along the longitudinal axis over the entire length of the clamping block (15) and has a width greater than the diameter of the through hole (16).

7. Component (1) according to claim 3, characterized in that a plurality of through holes (16) are present in the clamping block (15) along its longitudinal axis.

8. Component (1) according to any one of claims 1 to 7, characterized in that the connection means (7) are recesses capable of connecting corresponding connection means of the shaft.

9. A component (1) described in any one of claims 1 to 8, characterized in that the wall of the housing extending cylindrically from the housing base (3) has a thickness of 0.3 mm to 3 mm.

10. Component (1) according to any one of claims 1 to 9, characterized in that the component (1) comprises at least three fastening means (13) arranged at a distance from each other on the outer surface (12).

11. Component (1) according to claim 2, characterized in that the base surface (17) of the clamping block (15) is concave or flat in shape.

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