DE102014222771A1 - Gear and gear pairing with the gear - Google Patents

Abstract

With the gear geometry of spur gears, a distinction can be made between straight gears and helical gears in addition to other descriptive parameters. In the case of straight toothing, the teeth of the toothing extend parallel to the axis of rotation of the spur gear. In helical toothing, the teeth extend helically around the axis of rotation. The spur gearing has the advantage that no axial forces occur during operation. The helical gearing has the advantage that it operates particularly quietly in operation, but on the other hand generates axial forces as a result of the design. The invention has for its object to provide a gear and a gear pair with the gear, which or which allows a comfortable run with good operating characteristics. For this purpose, a gear 2a, b with at least a first and a second gear portion 3a, b, wherein the first and the second gear portion 3a, b in the axial direction to an axis of rotation R of the gear 2a, b are arranged adjacent to each other, wherein the first gear portion 3a, a first spur gear 4a and the second gear portion 3b carries a second spur gear 4b, wherein the first and the second spur gearing 4a, b have the same gear pitch p and the same pitch circle diameter, wherein the first and the second gear portion 3a, b in the direction of rotation to each other an offset V are arranged offset, proposed, wherein the first and the second gear portion 3a, b are offset by an offset between 0.1 · p and 0.9 · p to each other.

Description

The invention relates to a gear having at least a first and a second gear portion, wherein the first and the second gear portion are arranged in the axial direction to a rotational axis of the gear adjacent to each other, wherein the first gear portion carries a first spur gear and the second gear portion has a second spur toothing, wherein the first and the second sprocket teeth have the same gear pitch p and the same pitch diameter and wherein the first and the second gear portion are arranged offset in the circumferential direction to each other by an offset. The invention also relates to a gear pairing with this gear.

With the gear geometry of spur gears, a distinction can be made between straight gears and helical gears in addition to other descriptive parameters. In the case of straight toothing, the teeth of the toothing extend parallel to the axis of rotation of the spur gear. In helical toothing, the teeth extend helically around the axis of rotation. The spur gearing has the advantage that no axial forces occur during operation. The helical gearing has the advantage that it operates particularly quietly in operation, but on the other hand generates axial forces as a result of the design.

Against another technical background, namely the motivation of a quick and simple production, the document proposes DE 30 26 685 , which is probably the closest prior art, before a gear with a helical toothing, wherein the gear is composed of a plurality of lamellae, which are arranged axially adjacent to each other and which are slightly rotated in the circumferential direction to each other to represent a helical toothing. This makes it possible to produce a helical gear from a flat semi-finished, such as a sheet metal.

The invention has for its object to provide a gear and a gear pair with the gear, which or which allows a comfortable run with good operating characteristics.

This object is achieved by a gear with the features of claim 1 and by a gear pairing with the features of claim 6. Preferred or advantageous embodiments of the invention will become apparent from the dependent claims, the following description and the accompanying drawings.

An object of the invention is a gear, which is designed for a gear pair. The gear is designed as a spur gear and carries a circumferential toothing region. The gear has at least a first and a second gear portion. The first and second gear portions are arranged in the axial direction to a rotation axis of the gear adjacent to each other. In particular, it is provided that the first and the second gear portion are arranged immediately adjacent to each other and particularly preferably contact. Alternatively, a gear-free intermediate portion between the adjacent gear portions is arranged.

The first gear portion carries a first spur toothing, the second gear portion carries a second spur toothing. The spur gear teeth each have a plurality of teeth, wherein the teeth extend with the tooth tip and / or with the tooth base parallel to the axis of rotation. When Verzahnungsart can be any Verzahnungsart, particularly preferably the Verzahnungsart is designed as an involute. Preferably, the spur toothing extends in the axial extent over the entire width of the gear portion.

m:

Modul

d:

Teilkreisdurchmesser

z:

Zähnezahl

The first and the second spur gearing have the same gear pitch p and the same pitch circle diameter. Under the gear pitch p is understood in particular the arc length of the pitch circle of two adjacent teeth. Under the pitch diameter, in particular the pitch circle diameter of the gear is understood. Mathematically speaking, preferably: m = p / pi m = d / z

m:

module

d:

Pitch diameter

z:

number of teeth

The circumference of the gear in pitch circle diameter is preferably calculated by the product of gear pitch p and number of teeth z. At the same time, the circumference corresponds to the product of pitch circle diameter d and the number pi. Furthermore, it is preferably determined that the modulus m is the quotient of the gear pitch p and the number pi. Thus, the module m are equal to the first gear portion and the second gear portion.

The first and the second gear portion are arranged offset in the direction of rotation about the axis of rotation to each other by an offset. Figuratively speaking, starting from a uniform toothing, an axial section of the uniform toothing about the offset in the circumferential direction rotated to construct the first gear portion and the second gear portion.

In the context of the invention, it is determined that the offset between the first and the second gear section in the direction of rotation is selected between 0.1 · p and 0.9 · p. Preferably, the offset is between 0.3 × p and 0.7 × p. For a preferred embodiment, the offset is 0.5 * p.

It is an idea of the invention to propose a gear in which at least or exactly two gear sections are rotated relative to each other in the direction of rotation or offset. However, this should not be an "interpolating" rotation in order, for example-as described in the prior art-to simulate helical toothing over a lamella stack. Rather, the first and the second gear portion each form a spur toothing, wherein the first and the second gear portion are arranged in the circumferential direction by a step and thus significantly offset from each other. The step height is greater than 0.1 × p, preferably greater than 0.3 × p, and is in particular 0.5 × p.

In a mutual running of gears engaged usually takes place a change between a single engagement and a double engagement of the gears. There may even be a triple intervention. Considering a cross-section perpendicular to the axis of rotation, the two meshing gears only contact at one point in a single engagement, while in a double engagement, the two gears contact each other simultaneously at two points. Due to the constant change between the single engagement and the double engagement and possibly even the triple engagement, the stiffness behavior of the gear changes periodically. Thus, a single tooth of a gear is more heavily loaded in a single engagement and thus more deflected than two teeth of the gear during a double engagement. Due to the resulting behavioral stiffness jumps between the individual intervention and the double engagement, there is a Drehwegfehler of the gear, as this in the circumferential direction - figuratively speaking - in double engagement is less yielding than in the individual intervention. Thus results from the constant change between the single engagement and the double engagement a nonlinear behavior of the gear in the circumferential direction. In addition, due to the change between the individual intervention and the double intervention, noise emissions occur, it being known that straight toothings are louder in operation than helical toothings.

Due to the embodiment of the invention, a gear is divided into at least two gear portions, wherein the two gear portions are arranged offset in the direction of rotation to each other. As a result, the phases of the individual engagement and of the double engagement of the two gearwheel sections are also offset in the direction of rotation. As a result of this offset, the number of transitions between the individual engagement for double engagement and in the opposite direction arises at least or exactly twice as often as in the case of a conventional gear. If the toothed wheel has three toothed wheel portions with two different offsets, the transitions are even three times as frequent, etc. However, the force to be transmitted is also distributed over the at least or exactly two toothed wheel portions, so that the negative effects resulting from the change between individual engagement and double engagement, such as stiffness jumps and noise emissions, are less pronounced.

In an overall view, the division into at least or exactly two gear sections doubles or multiplies the number of transitions, but reduces their negative effects. Thus, a device is provided by the gear according to the invention, which shows in operation compared to conventional gears a better performance and a quieter running.

It is preferred that the gear has only gear portions of two offset groups. The gear portions of the one offset group has no offset or defines the 0 offset. The gear portions from the other offset group uniformly have a common offset.

It is particularly preferred that the axial width of all gear portions with offset and the axial width of all gear portions are added up without offset added. Equal distribution between a total area with offset and a total area without offset distributes the loads evenly. This training further promotes smoothness and overall performance.

In a preferred embodiment of the invention, the gear is formed in one piece and in particular made of a common semi-finished product. In an alternative implementation, the gear portions are formed separately and rigidly connected together. For example, the gear sections can be connected to one another in a material-locking manner and / or by means of positive and / or frictional connections, such as screw connections.

To emphasize the aspect of the load distribution on the at least or exactly two gear sections, it is preferred that the Gear portions of the same, in particular identical, material are formed or at least made of the same type of material. Under the same type of material material types such as metal, plastic understood.

In a possible constructive embodiment of the invention, the gear has exactly two gear sections. The two gear portions are particularly preferably arranged immediately adjacent and / or in the axial direction contacting each other. Preferably, the axial widths of the exactly two gear portions are the same to evenly distribute the load. It is also preferred in a development that the offset is 0.5 * p, so that there is a regular distribution of the transitions between the individual intervention and the double intervention in the circulation direction.

In an alternative structural embodiment of the invention, the gear has at least or exactly three of the gear sections. Two of the gear portions are not offset from each other and, in particular, define the 0 offset, while one of the gear portions has an offset from the other two gear portions. It is further preferred that the at least or exactly three gear portions are arranged with respect to their straight teeth mirror-symmetrical to a center plane of the gear. In particular, it is provided that, for example, axially on the outside two first gear portions and centrally between the two first gear portions, a second gear portion is arranged, which has an offset relative to the two first gear portions. Preferably, the two first gear portions, in particular their Geradverzahnungen, the same in the axial width. Furthermore, it is particularly preferred that the second gear portion, in particular the second straight toothing, have the same axial width as the sum of the axial widths of the first gear portions, in particular of the first straight toothings. With such a symmetrical structure is achieved that no axial forces are generated in the gear during operation.

Another object of the invention is formed by a gear pair having a first and a second gear, which mesh with each other. Each of the gears is designed according to one of the preceding claims. The two gears may be formed identically with respect to the gear portions, in particular to the Geradverzahnungen. However, it is also possible that the two gears have, for example, different pitch circle diameter. The gears mesh with each other with a toothed portion in a first pair of teeth and at the same time with each other a gear portion in a second gear pairing with each other. Optionally, the gears mesh with each other with a toothed portion in a third, fourth or further gear pairing.

It is particularly preferably provided that the profile overlap of the gear pairing is greater than 1 and preferably integer executed. For example, the profile overlap for each of the gear pairings is at least or exactly 2, in particular in an unloaded state of the gear pair.

By selecting the profile overlap greater than 1, the first pair of teeth can alternately assume a first single engaged state and a first double engaged state during operation. Likewise, the second gearing pair may alternately assume a second single engagement state and a second dual engagement state during operation. In the single-engagement state, the two gears contact each other in a cross-section perpendicular to the axes of rotation at exactly one point on a tooth. In the double engagement state, the two gears also contact, viewed in cross-section, in exactly two points, the two points being distributed over two different teeth.

In a preferred embodiment, the offset between the first and the second gear portion, in particular for each of the gears, is selected so that in a balancing state, the gear pair with the first gear pairing in the single engaged state and with the second gear pairing in the double engaged state or the first Gear pairing in the double engaged state and the second gear pairing is in the single engaged state. The offset is thus dimensioned such that the two gear pairings are arranged opposite in relation to the engaged state in the compensating state of the gear pair. Through this preferred embodiment it is achieved that the transitions between the single engaged state and the double engaged state of the two gear pairings are shifted in the direction of rotation to each other. This achieves the advantage already described above that the number of transitions from the single engaged state to the double engaged state or the opposite direction is indeed doubled or even multiplied, but the intensity of these transitions is reduced so that a smoother running of the gear pairing is achieved overall.

It is particularly preferably provided that the gear pairing the compensation state for a cumulative angle range of at least 180 degrees, preferably for a cumulative angular range of at least 270 degrees and in particular for a cumulative angular range of at least 355 degrees for at least one of the gears occupies. An accumulated angular range is to be understood as meaning the sum of all partial angle ranges in which the gear pairing assumes the compensating state. This close-to-product design is based on the consideration that due to not infinitely short transitions between the single engaged state to the double engaged state and in the opposite direction to operating conditions of the gear pair can occur, in which there is the same engaged state in both teeth pairings. Although it is preferred that the non-compensating state with respect to an accumulated angular range in the direction of rotation turns out to be as low as possible, taking into account the possible realization, however, the accumulated angular range for the compensating state can also assume the abovementioned values.

If one considers the gear pairing, in particular designed as an involute toothing, a first engagement line results for the first gear pairing and a second engagement line for the second gear pairing. The engagement line describes the line of engagement points between the two gears adjacent to a single engagement area. In this case, the first engagement line has two first double engagement areas and a first single engagement area, wherein the two first double engagement areas are arranged on both sides of the first single engagement area. In the same way, the second engagement line has two second double engagement areas and one second single engagement area. The offset between the gear portions is selected such that in one or the compensation state, the first double engagement region with the second single engagement region and / or the first single engagement region with the second double engagement region result in the same angular position of the gears to each other. This representation represents a supplement or an alternative to the illustration described above.

Functionally, it is preferred that the offset is selected such that the number of jump changes is doubled and the amplitude of the stiffness jumps is reduced and / or evenly distributed with respect to the direction of rotation of the gear. The gear pair can be formed with gears, which each have exactly two gear portions. In an alternative embodiment, the gear pairing can also be formed by gears, which have exactly three or more gear portions. However, it is preferred that the gear portions can be divided into two groups, namely in a first group without offset or with 0 offset and in a second group, which each have the same offset. For example, in three gear portions, the two outer gear portions of a common group and the inner gear portion of the other group are assigned. Thus, the two outer gear portions have no or the same offset.

Further features, advantages and effects of the invention will become apparent from the following description of preferred embodiments of the invention and the accompanying figures. Showing:

1 a schematic three-dimensional representation of a gear pair with two gears as an embodiment of the invention;

2 a schematic, axial plan view of one of the gears in the 1 to describe the offset;

3 a schematic side plan view of the two gears to illustrate the various areas of engagement with the gears;

4 a schematic lateral plan view of both gears for illustrating the engagement line in the pairs of teeth;

5 a highly schematic representation of the shifted engagement lines in the two gear pairs in the gear pair in the 1 ;

6 a three-dimensional view of a second embodiment of the invention.

The 1 shows a schematic, three-dimensional representation of a gear pairing 1 with two gears 2a , b. The two gears 2a , b comb each other. The two gears 2a , b may be formed identically, alternatively, these have different pitch circle diameter to each other. However, the basic structure is with both gears 2a , b equal, so that the construction in the 1 by the gear 2a is explained, however, the corresponding areas of the gear 2 B are provided with the same reference numerals.

The gear 2a has a first and a second gear section 3a , b on. The two gear sections 3a , B are axially adjacent and in this embodiment immediately adjacent in the axial direction to a rotation axis R of the gear 2a arranged. The first gear section 3a has a first spur toothing 4a , the second gear section 3b has a second spur toothing 4b on. The spur toothing 4a , b extends over the full axial width of the gear sections 3a respectively. 3b , b Each of the spur gears 4a , b carries a plurality of teeth 5 , whose tooth back or tooth base are aligned parallel to the axis of rotation R.

The first and second spur gearing 4a , b are in the embodiment in the 1 are of identical design and thus can theoretically be formed from a common straight toothing by division and rotation of an output toothing by an offset V (FIG. 2 ) in the direction of rotation about the axis of rotation R are constructed. With regard to gear parameters, the spur gears have 4a , b the same gear pitch p and the same pitch circle diameter.

The first gear section 3a of the gear 2a forms with the second gear portion 3b of the second gear 2 B a first gear pairing 8th and the second gear section 3b of the first gear 2a with the first gear section 3a of the second gear 2 B a second gear pairing 9 ,

The 2 shows a schematic side view of the gear 2a , wherein the solid line of the first gear section 3a with the first straight toothing 4a and the dashed line the second gear portion 3b with the second spur toothing 4b is shown. The gear pitch p is the arc length in the pitch circle or pitch circle between two teeth 5 illustrated. The offset V between the first spur toothing 4a and the second spur toothing 4b or the first gear section 3a and the second gear portion 3b is selected in a range between 0.1 · p and 0.9 · p. Particularly preferably, the offset is exactly 0.5 × p, so that the teeth 5 the first and second gear portions 3a , b are distributed regularly in the circumferential direction about the rotation axis R.

In the 3 is a schematic side view of the two gears 2a , b at one of the gear sections 3a , b shown. It is shown that a leading edge of the teeth 5 in operation a single intervention area 6 and in the radial direction adjacent thereto a double engagement region 7 having. In a mutual run contact the gears 2a , b on two different teeth 5 in a double intervention area 7 After that, the contact goes into a single intervention in the single intervention area 6 above. In the 4 is one of the gearing pairings 8th or 9 shown in the mutual run, with an intervention line 10 is shown. The intervention line 10 connects the points of contact of the gear pairing 8th . 9 during the mutual process. Here, between the points A, B and D and E is a double intervention area 7 and between the points B and D, a single intervention area.

Like in the 5 shown is the offset V is chosen so that the engagement line 10 the first gear pairing 8th to the intervention line 10 the second gear pairing 9 is moved. This ensures that at a mutual drainage of the gears 2a , b at the same time the first gear pairing 8th in a single engagement state and the second gear pairing 9 is in a double engaged state, or the first intermesh pair is in a double engaged state and the second intermesh pair is in a single engaged state. This opposite arrangement is also referred to as a compensation state. Because of that the gear pairing 1 related to the gear 2a is located over a very large accumulated angle range in the compensating state, a very quiet and smooth running is achieved. It is provided in particular that the accumulated angular range is more than 355 degrees about the axis of rotation R of the first gear 2a extends.

By the offset V is achieved that the stiffness jumps, which results from a transition from the single engagement to the double engagement in one of the toothed pairs 8th . 9 Although doubled in number, due to the even load distribution on the two gear pairings 8th . 9 however the intensity is reduced. As a result, a uniform run is promoted overall.

The 6 Finally, in a schematic three-dimensional representation, a second embodiment of the invention of the gear pairing 1 , In the second embodiment of the invention, each of the gears 2a , b two first gear sections 3a and a second gear portion 3b on, wherein in each case the second gear section 3a axially between the first gear portions 3a is arranged. The axial width of the gear sections 3a , b is such that the sum of the axial widths of the first gear sections 3a the axial width of the second gear portion 3b equivalent. The first two gear sections 3a are each opposite to the second gear portion 3b rotated by the offset V in the direction of rotation. This embodiment is characterized by a particularly strong axial symmetry.

LIST OF REFERENCE NUMBERS

1

 gear pair

2a, b

 gears

3a, b

 gear sections

4a, b

 straight teeth

5

 teeth

6

 Single-meshing area

7

 Double contact area

8th

 first gear pairing

9

 second gear pairing

10

 contact line

p

 gear pitch

R

 axis of rotation

V

 offset

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 3026685 [0003]

Claims (10)

Gear ( 2a , b) having at least a first and a second gear portion ( 3a , b), wherein the first and the second gear section ( 3a , b) in the axial direction to a rotation axis (R) of the gear ( 2a , b) are arranged adjacent to each other, wherein the first gear portion ( 3a ) a first spur toothing ( 4a ) and the second gear section ( 3b ) a second spur toothing ( 4b ), wherein the first and the second spur toothing ( 4a , b) have the same gear pitch p and the same pitch diameter, wherein the first and the second gear portion ( 3a , b) are offset in the direction of rotation relative to each other by an offset (V), characterized in that the first and the second gear portion ( 3a , b) are offset by an offset between 0.1 · p and 0.9 · p offset from one another. Gear ( 2a , b) according to claim 1, characterized in that the gear ( 2a , b) is formed in one piece and / or that the gear sections ( 3a , b) are formed separately and rigidly connected to each other. Gear ( 2a , b) according to claim 1 or 2, characterized in that the gear sections ( 3a , b) are made of the same material or of the same type of material. Gear ( 2a , b) according to one of the preceding claims, characterized in that the gear ( 2a , b) exactly two gear sections ( 3a , b). Gear ( 2a , b) according to one of the preceding claims 1 to 3, characterized in that the gear ( 2a , b) at least or exactly three of the gear sections ( 3a , b), wherein the at least or exactly three gear sections ( 3a , b), in particular their straight toothing ( 4a , b) are arranged mirror-symmetrically to a median plane. Gear pairing ( 1 ) with a first and a second gear ( 2a , b), each of the gears ( 2a , b) according to any one of the preceding claims, wherein the gears ( 2a , b) each having a toothed section ( 3a . 3b ; 3a . 3a ) in a first gear pairing ( 8th ) and each with a gear section ( 3b . 3b ) in a second gear pairing ( 9 ) comb each other. Gear pairing ( 1 ) according to claim 6, characterized in that the first pair of teeth ( 8th ) can assume a first single engaged state and a first double engaged state and that the second toothed pairing ( 9 ) can assume a second single engagement state and a second dual engagement state, wherein the offset (V) between the first and the second gear portion ( 3a , b) is chosen so that the gear pairing ( 8th . 9 ) in a balancing state with the first gear pairing ( 8th ) in the single engagement state and with the second gearing pairing ( 9 ) is in the double engaged state or vice versa. Gear pairing ( 1 ) according to claim 7, characterized in that the compensating state for a cumulative angular range of at least 180 °, preferably for an accumulated angular range of at least 270 ° and in particular for an accumulated angular range of at least 355 ° occupied. Gear pairing ( 1 ) according to one of claims 6 to 8, characterized in that the first gear pairing ( 8th ) a first intervention line ( 10 ) and the second gear pairing ( 9 ) a second intervention line ( 10 ), wherein the first intervention line ( 10 ) two first dual intervention areas ( 7 ) and a first single intervention area ( 6 ) and wherein the second intervention line ( 10 ) two second dual intervention areas ( 7 ) and a second single intervention area ( 6 ), wherein the offset (V) is selected so that in one or the compensation state, the first double engagement region ( 7 ) with the second single intervention area ( 6 ) and / or the first single intervention area ( 6 ) with the second double intervention area ( 7 ) superimposed. Gear pairing ( 1 ) according to one of the preceding claims, characterized in that the offset (V) is selected such that the number of jump changes is doubled and the amplitude of the stiffness jumps is reduced and / or equally distributed with respect to the direction of rotation of the gear.

Images