EP2435721A1

EP2435721A1 - Shaft-hub connection having polygon profile

Info

Publication number: EP2435721A1
Application number: EP10725022A
Authority: EP
Inventors: Petar Gugic; Inge Klobasa
Original assignee: PIV Drives GmbH
Current assignee: PIV Drives GmbH
Priority date: 2009-05-30
Filing date: 2010-05-31
Publication date: 2012-04-04
Also published as: DE102009023449A1; WO2010139441A1

Abstract

The invention relates to a shaft-hub connection having a polygon profile with rounded corners, wherein at least two corners are present and wherein the corners are rounded with a small radius and are connected to a section having a large radius, wherein the neighboring radii merge tangentially and wherein in preferred embodiments the centers of the radii have the same distance, or in further embodiments have a different distance, to the center of the polygon.

Description

Shaft hub connection with polygonal profile

Description

The invention relates to a shaft-hub connection with a polygonal profile with rounded corners.

Shaft-hub connections are important technical means for transmitting torques. Particularly widespread shaft-hub connections are, for example shaft-hub combinations with actually unsuitable for a transmission of torque fits, in which for the torque transmissions mentioned the shaft-hub connection is provided with at least one key or has a wedge or square profile , Such compounds are known to be relatively difficult to produce in the required quality and precision.

Alternatively, pure press seats are possible for shaft-hub connections. Even with these, however, a high manufacturing precision is required. In addition, shaft-hub connections with interference fit have the disadvantage that the interconnected parts are no longer axially against each other.

Some of these disadvantages can be overcome by the use of

Polygonal profiles, as standardized with the standards DIN 3271 1 or DIN 32712.

In DIN 32711, a substantially triangular polygon profile is described, which is called "P3G" and is a uniform thickness.This polygon profile represents a special form of a trochoid and in particular has the following characteristic features: This profile has little or no notch effect. It is possible with him a higher torque transmission compared to other form-fitting shaft-hub connections. This is z. B. attributable to missing notch effects that occur at feather key or wedge profiles. Under torque center shaft and hub z. In addition, if such a polygonal profile and circular cross sections are provided on a component, they can be machined in the same clamping Connect shaft collar.

A disadvantage of this "P3G" profile, however, is that components connected to it are not longitudinally displaceable under load, that is to say under torque.

If a longitudinal displacement under torque is required, the substantially quadrangular polygonal profile "P4C" is proposed according to DIN 32712. This polygonal profile is not only composed of parts of a trochoid but also has circular arc sections.

A disadvantage of the shape of the polygon profile "P4C" is that a corresponding hub mount can not be made with loops, but rather the corresponding images must be cleared because of their disharmonic profile shape cost.

Object of the present invention is therefore to provide a shaft-hub connection, which has the positive characteristics of the known polygon shaft-hub connections, but in particular also with conventional grinding machines can be produced and in particular also has sandable hubs.

This object is achieved in that at a shaft hub connection with a polygonal profile and rounded corners a number of at least two corners is present and the corners with small Radius r1 are rounded and are connected to a section with a large radius R2, wherein adjacent radii tangentially merge into each other.

The choice of the two radii r1 and R2, which is adapted to the particular requirement, achieves the familiar shape of the trochoid, in that the geometric shape of a shaft-hub connection can be adapted to a specific application and, in particular, to the specific torque to be transmitted.

Likewise, an optimization of the material to be removed and the required installation space is possible.

The radius r1 is smaller than the radius rW of the shaft and the radius R2 is greater than this radius rW of the shaft.

In a particularly preferred embodiment, the shaft-hub connection has a profile with an odd number of corners, wherein the radii of diametrically opposite corners and portions between two corners may have the same center. This gives a so-called equal thickness, the particular z. B. can be easily checked for dimensional accuracy in its production.

But it is also within the scope of the invention, if in such a case the odd number of corners, the radii of diametrically opposite corners and sections between two corners have different centers, as long as the adjacent radii merge tangentially into each other.

Even with an even number of corners, the radii of mutually attributable corners or sections between two corners can lie with their centers on different circles. A significant advantage over the prior art is the fact that the intended profiles, which in very particularly preferred embodiments of the invention have a "corner" number ≥ 5, can transmit a higher torque with simultaneously lower specific pressures there is a possible under load axial displacement.

In addition, there is a defined gap between shaft and hub with suitable mating, with the hydraulic seal can be achieved if necessary. This gap is used both sealing and lubricating. For this purpose, the profiles of shaft and hub run in particular parallel to each other.

Furthermore, the shaft-hub connection described here has a definable backlash, which facilitates their technical use.

In a further preferred embodiment, however, not all of the shaft and hub opposite portions extend parallel to each other. Rather, it is provided that two different radii are provided in at least one of two sections lying on the hub and shaft. As a result, an axially extending channel is generated in this area, the need also z. B. for the passage of hydraulic oil, etc. can be used by the profile is not parallel to a corresponding corner or a corresponding portion at a corner or in a lying between these sections.

The inventively provided profiles can be produced with conventional numerically controlled machine tools. The circular tool paths to be created are much easier to describe and define than is possible with the equations given in the prior art for polygon profiles "P3G" or "P4C". This is due in particular to the fact that the previous polygonal profiles are only generated as trochoidal. Under a trochoid, the curve is closed understand that describes a point inside or outside a circle that rolls on a base curve, in particular a fixed circle.

In the previously known and used polygon profiles such curves were determined in particular by the kinematics of mechanically controlled polygon grinding machines. It is always expressly pointed out in the standard DIN standards that the present invention provided easier use of two tangentially merging radii to define the curve can be used only as an aid to a graphical representation, but not for an actual execution ,

The now proposed shaft-hub connection, even with a larger number of "corners" that are to be described and generated by simple geometrical relationships and related to each other, thus overcomes a technical prejudice to be evaluated opinion that suitable polygon profiles only by geometrically complex trochoid equations are to be described.

Incidentally, in the standard literature, only up to four "corners" are proposed for polygonal profiles, which is related to the above-described complex fabrication It should be pointed out once again that in the known polygonal profiles, not only specific tools for their manufacture are sometimes produced but may even be specific components for the machine tool with which the polygon profile is to be made.

In order to ensure the manufacturability of a polygonal profile according to the invention, it is proposed, at a given with decimal places accuracy of a numerically controlled machine tool, the

To limit quotients of the number of vertices and 360 ° to values which can be represented exactly with these decimal places and thus to polygons that can be easily produced with the processing machine in the desired quality. In order for the angles over which the circular arcs described by the radii extend to be an integer and thus a profile to be produced particularly easily, in a particularly preferred embodiment of the invention, it is proposed in particular that the envisaged corner number of the profile has an (integral) divider of 360 represents. - Such a divider then has no decimal places.

Manufacturing technology, it is possible to apply the described polygon in an external grinding on the shaft. It is essential that the radius of the "corners" passes tangentially into the radially configured section between two "corners".

Due to the tangential transition, an outer contour profile is achieved overall on the shaft, which has no concave but only convex sections. At the same time only concave sections are present at the hub. This ensures both good manufacturability and measurability, which is necessary for high-quality production.

But it is also possible to choose a number of "corners", which gives a quotient of 360 °, a value of the intended numerically controlled processing machine, which is determined in the processing accuracy by representable by her decimal places, with their decimal places still exactly can be represented.

In an embodiment with an odd number of corners, as described above, in conjunction with equal radii centers of diametrically opposite radii, a uniform thickness is obtained. This special shaft and hub profile thus has a particularly easily measurable shape: put the shaft z. B. in a caliper between two parallel surfaces, their distance from each other is always the same, regardless of the angular position of the shaft between the surfaces. The same applies to the Hub profile, the two buttons z. B. an internal micrometer is determined by these are set to a maximum value of their distance.

Further advantages and features of the invention will become apparent from the following description of exemplary embodiments. It shows

Figure 1 is a section through a shaft-hub connection with five rounded "corners";

Figure 2 is a section through a shaft with two rounded "corners" Figure 3 is a section through a shaft with three rounded "corners",

FIG. 4 shows a section through a further shaft for a shaft-hub

Connection with three rounded "corners",

5 shows a section through a shaft-hub connection with four rounded "corners"; [0027] FIG. 6 shows a section through a shaft-hub connection with five rounded "corners".

FIG. 7 shows a section through an embodiment of a shaft with five rounded "corners"

Figure 8 shows a section through a hub with nine rounded "corners" Figure 9 shows the longitudinal section through a shaft and a conical disk pair with a shaft-hub connection.

FIG. 1 shows a section through a shaft-hub connection. Such is used when torque has to be transmitted between shaft and hub.

A very specific application example is shown in FIG. 9 for this purpose. In this one recognizes the longitudinal section through a shaft of a bevel gear. This has a fixed conical disk 1, which is made in one piece with the shaft 2. Furthermore, one recognizes a displaceable on the shaft 2 cone pulley 3. The shaft 2 has a polygonal ground section 4, on which the displaceable conical disk 3 is seated with a hub portion 5. This is shown in the figure 1 in section along the line II according to FIG. It can be seen that provided with a central bore 6 shaft 2 in its polygonal ground section 4, the dimensionally accurate in its inner contour also polygonal ground hub portion 5 of the movable conical disk 3 is seated.

About the polygonal shape, it is possible to transmit from the shaft 2 torques on the sliding cone pulley 3 or from the conical disk 3 to the shaft second

It should be mentioned here that instead of a conical disk gear as shown here with a displaceable conical disk 3, a conventional gear transmission is possible, in which instead of a displaceable conical disk 3 would then provide a sliding gear.

In the example shown here, the polygonal profile of the ground section 4 has an odd number of "corners" 7. In the example shown here, this number is 5. These "corners" are - as in the other examples shown here evenly around the circumference of the shaft distributed.

These "corners" are each rounded off with a small radius r1 and are each connected to sections 8. These sections 8 are likewise produced with a constant radius R2 It is essential that two mutually adjacent radii r1 and R2 merge tangentially into one another.

Due to the odd number of "corners" are over the center of the shaft 2 diametrically each have a "corner" 7, which is rounded with a small radius r1, and a section 8, which lies between two "corners" 7 and the Radius R2 has.

In the specific embodiment shown here, the radii r1 and R2 have the same center. This achieves a "same thickness", as discussed below. It should be mentioned here that the radius r1 is considerably smaller than the nominal radius of the shaft 2 and the radius R2 is considerably larger than this nominal radius of the shaft.

2 shows the section through a shaft with a polygon profile with two rounded "corners." This too consists of several sections in which circular arc sections with a radius of curvature r1 at transition lines 9 transition tangentially into circular arc sections 8 having a large radius of curvature The resulting profile resembles an oval, but it is not, because a "real oval" does not consist of only four circular arc sections.

In the example shown here, one recognizes further that the shaft has a circumference of, for example, 70 mm, while the circle on which the radii r1 have their center has a diameter of about 36 mm.

Another example of a polygonal profile can be seen in Figure 3, where there are three rounded "corners" 7. These, too, transition tangentially into arc sections 8 at transition lines 9. The three "corners" 7 are evenly distributed over the circumference of the profile and have between them an angle of 120 °.

The radius M with which the "corners" 7 are rounded is chosen to be 8 mm in the example shown here, which results in a radius for an inscribed circle to be inscribed in the polygonal profile which just barely touches the sections 8 in its middle point. of 32 mm and the radius of a circumference, which just touches the "corners" 7 at its center, of 37 mm.

This is in the case that the radius of section 8 is on the same

Center is located, as the radius of the diametrically opposite "corner" 7, so that the profile achieved is a uniform thickness. But it is also possible to place the center of the radii r1 and R2 on different circular lines. This is shown for example in FIG. 4. Here, too, 7 circular arcs with a radius r1 of 8 mm are provided for the "corners" with a circumference diameter of 37 mm.The choice of a different radius R2 results in "flatter" sections 8, which in turn tangentially into the transition lines 9 rounded off "corners" 7. In the example shown here then results in an inscribed circle with an inner diameter of only 28 mm.

5 shows a shaft-hub connection with four rounded "corners" 7. These are in turn connected by radii sections 8. While the "corners" 7 are rounded with a radius r1, the sections 8 have a circular arc-like course a radius R2. The shaft has a minimum diameter of 36.06 mm and a maximum diameter of 38 mm. However, the radius r1 is considerably less than the resulting minimum shaft radius r, while the radius R2 is considerably larger than the maximum shaft radius rW which is calculated therefrom.

6 shows the section through a shaft-hub connection with five rounded "corners" 7 distributed uniformly around the circumference In the example shown here, the radius of curvature r1 is set at 7.5 mm The radius of the diametrically opposite section 8 is set at 27.472 mm, resulting in a circumference with a diameter of 36 mm and an inscribed circle with a diameter of 33.944 mm The two radii r1 and R2 have the same center point, which is 10.5 mm from the shaft center 10 The number of "corners" 7 in this particularly preferred embodiment is five with an even divisor of 360. Thus, the angle in the circumferential direction on the shaft between two adjacent "corners" is 72 °, an amount without a decimal point Produce particularly well and accurately with a conventional numerically controlled machine tool. In the figure 7 is the schematic diagram of a shaft-hub connection is shown, which is comparable to the shaft-hub connection in Figure 6. Again, there are five "corners" 7 which, in the example shown here, have a radius of curvature r1 of 7 mm These rounded corners pass over circular arcs 8 having a radius R2 of 26.44 mm The resulting shaft thus has a minimum diameter of 32 mm and a maximum diameter of 34 mm However, in the example shown here, a single section 1 1 with a different radius R3 of 50 mm is used in the example shown here, with a combination of this corresponding shaft with a hub , which works exclusively with sections 8, which have a radius R2 of 26.44 mm, results in the region of section 1 1 an axially extending channel section 12, which can be used, for example, for the passage of hydraulic or lubricating oil Section 1 1 while the portion of the wave profile is not parallel to the corresponding portion of the hub profile, w ie in the other embodiments described herein. Of course, it is also possible, instead of the radius R3 of a section 8, to select the radius r1 of a "corner" 7 such that the channel 12 forms in the region of this "corner" 7 of a shaft and the corresponding "corner" of a hub.

A hub is shown in Figure 8 with nine "corners" 7. These are evenly distributed around the hub at an angle of 40 ° between them The hub has a nominal diameter of 36 mm and the nine "corners" 7 are one Radius r1 of 7.5 mm rounded. The sections 8 between two adjacent corners 7 have a radius R2 of 28, 18 mm. Also in this example, the radii r1 of the "corners" 7 with the radius R2 of a respective diametrically opposite section 8, which lies between two "corners" 7, the same center. In the embodiment of a hub with nine "corners" shown here, this therefore has an effective diameter of 35.68 mm. In the above embodiments, both the waves in their polygonal section and the precisely fitting in their inner contour also ground polygonal hub portions.

About the said polygonal shape, it is possible from the waves 2

To transmit torques to the slidable hubs or vice versa.

In the embodiments in which the radii r1 and R2 each have the same center, you get with the shaft and hub profiles easily nachmessbare forms: If you put the shaft z. B. in a caliper between two parallel surfaces, so their distance from each other is always the same, regardless of the angular position of the shaft between the surfaces. The same applies to the hub profile, the two buttons z. B. an internal micrometer is determined by these are set to a maximum value of their distance. This is called "equal thickness".

Manufacturing technology, it is possible to apply the polygons described above in a Außenschleifvorgang on the waves. As mentioned, it is essential that the radii of the "corners" pass tangentially into the radially configured sections between two "corners". Due to the tangential transition, an outer contour profile is achieved overall on the shafts, which does not have any concave but only convex sections. This ensures the desired good manufacturability and measurability.

In particularly preferred embodiments, the number of "vertices" is not only odd and> 5. In particularly preferred embodiments it is also a divisor of 360. Thus, the angle on the wave between two adjacent "corners" is an even amount. For example, with five "corners" 72 °, with nine "corners" 40 ° etc.

But it is also possible to choose a number of "corners", which gives a quotient of 360 ° a value that provided by the intended for the production of the shaft-hub connection numerically controlled machine tool is determined in the processing accuracy by representable by her decimal places can still be accurately represented with their decimal places.

A significant advantage of the invention is that, in particular in polygonal shaft-hub connections, which has a "corner" number of ≥ 4, in particular ≥ 5, the shaft and the hub are mutually displaceable even under load and at the same time between shaft and hub a sufficiently tight seat is present, with the hydraulic sealing is achieved if necessary.

Claims

Patent claims

Shaft hub connection with a polygonal profile with rounded corners, characterized in that it has corners (7) which are rounded with a small radius (M) and with large radii (R2, R3) are connected, wherein adjacent radii (M, R2, M, R3) merge tangentially.

2. shaft-hub connection according to claim 1, characterized in that the number of corners (7) ≥ 2, in particular ≥ 5.

3. shaft-hub connection according to one or more of the preceding claims, characterized in that at an odd number of corners (7) the radii (M, R2) of diametrically opposite corners (7) and sections (8) between two Corners (7) have the same center.

4. shaft-hub connection according to one or more of the preceding claims, characterized in that at a given with decimal places accuracy of a numerically controlled machine tool, it has a number of corners (7), so that the quotient of number of corners (7) and 360 ° with the decimal places of the processing machine is exactly displayed.

5. Shaft-hub connection according to one or more of the preceding claims, characterized in that the number of corners (7) is a divisor of 360.

6. shaft-hub connection according to one or more of the preceding claims, characterized in that the profiles of the shaft and the hub are parallel to each other.

Shaft hub connection according to one or more of the preceding claims, characterized in that wave and hub profiles at least at a corner (7) or in a section (8) are not parallel to a corresponding corner or a corresponding portion.