The invention relates to a unitary case for an angular drive of a transmission unit having the individual features of the characterizing portion of claim 1. It also relates to a case for a transmission unit and a transmission unit.
Transmission units are available in many different configurations. They differ, for example, with regard to how the speed/torque conversion is realized, which can be purely mechanical or combined with other converting options, for example. Especially for the transmission units with purely mechanical power transmission or with a mechanical combined with another power transmission the requirement for a universally applicable transmission unit is increasing. In order to realize the output drive at a certain angle relative to the transmission input shaft, angular drives are used for such transmission units which are combined with a base transmission unit. With these, a certain angle can be realized between the transmission input shaft and the transmission output shaft. For varying requirements, i.e. varying output angles, varying drive torque transmission and tilting angles relative to the road, a separate, specially configured transmission case or a certain unitary case has to be provided which encompasses the angular drive accordingly. Due to the many different case variants that are possible and the low degree of standardization production is more complex and costs are high.
Therefore, the aim of the invention is to further develop a case for a plurality of angular drives for use in transmission units with mechanical or combined power transmission such that the overall transmission unit can be equipped with a standardized case for varying output drive variants and that the overall transmission unit will have a minimal overall length.
It should also be possible to develop the overall transmission unit for various application requirements by means of an easy modification of a base transmission unit. In particular, the possibility of creating a unitary case for realizing the most varied angular drives should be provided. The solution of the invention should also be characterized by minor constructive efforts.
The solution of the invention is characterized by the features of claims 1, 10 and 13. Advantageous embodiments are reflected in the sub-claims.
In accordance with the invention, a unitary case for a plurality of angular drives comprising at least one bevel gear step with a first bevel gear and a second bevel gear for realizing various angles between a transmission input shaft and a transmission output shaft, where the second bevel gear can be coupled to the transmission output shaft in an at least indirect rotation-proof manner, for a plurality of the theoretically possible angular outputs has a virtually constant multiplication i and a constant outside diameter of the individual bevel gears with identical outside dimensions. In the unitary case, bearing receiving devices are assigned to the transmission output shaft and/or the second bevel gear. Said devices are formed by the inside contour of the unitary case and/or by replaceable bearing support elements that are dimensioned for receiving the bearings of the transmission output shaft.
Most of the theoretically possible angular drives that can be placed in the unitary case can be defined by two limit positions of the intersecting points of the flank lines of the bevel gears. A first limit position for the angular drive with the largest theoretically possible or desired angle between the transmission input shaft and the transmission output shaft is characterized by the intersection located closest to the case and a second limit position for the angular drive with the smallest theoretically possible angle between the transmission input shaft and the transmission output shaft is characterized by the intersection of the flank lines located furthest away from the case. The limit positions preferably define a range between 90 and  less than 180xc2x0 for the angular drive.
Therefore, the individual angular drives differ merely with regard to the angle between the transmission input shaft and the transmission output shaft in installed condition, which also corresponds to the angle between the bisecting lines of the individual bevel gears and thus the entrance and exit of the angular drive. The solution of the invention allows that various angular outputs are encompassed by one single case. The output angle is determined only by the production method, especially by how the inside contour is formed by means of milling, cutting or the like, and by the configuration of the bearing receiving devices. Therefore, with regard to the dimensions of the transmission unit the customer does not depend on various angular outputs. Instead, a unitary case can be offered for a transmission unit consisting of a base transmission unit with various angular outputs.
The inside contour for any theoretically possible angle between the transmission input shaft and the transmission output shaft can be provided by means of metal cutting the inside wall of the case accordingly. When a corresponding bearing receiving device is used, it preferably has two bearing support elements that are assigned to the transmission output shaft, each for receiving at least one bearing, a first bearing support element and a second bearing support element.
The bearing support elements each form a running surface for the individual bearings. The first bearing support element serves to support the end area of the transmission output shaft in the case, while the second bearing support element serves to support the transmission output shaft in the area of the exit of the case.
According to an especially advantageous embodiment with a minimum number of components, at least one of the bearing support elements, the first and/or second bearing support element, forms a part of the outside wall of the case. Preferably, both bearing support elements are components of the case.
According to a further development, the second bearing support element is already provided with connections and/or lead-throughs for fuel lines and/or ducts for electric lines so that these can be additionally modified for a certain angular drive separate from the rest of the case.
Further standardization is achieved by disposing a second heat exchanger on the second support element.
The bearing support elements can be mounted on the inside wall of the case in various different ways, for example by means of mounting elements. The bearing support elements preferably have uniform outside dimensions, especially in the surface areas contacting the inside wall of the case or interacting with indentations or projections on the inside wall of the case. This offers the advantage that the unitary case without the bearing support elements is also configured uniformly for all theoretically possible angular drives, and only the actual support surfaces for the bearings on the bearing support elements will vary.
The case for a transmission unit comprising a base transmission unit and an angular drive with a base transmission case that is assigned to the base transmission unit is equipped with a unitary case that is assigned to the angular drive as defined in any of the claims 1 to 10.
If, according to a special embodiment of the base transmission unit, a plurality of channels for supplying fuel and/or lubricant and/or coolant is disposed in the base transmission case, respective complementary connecting channels in the unitary case are assigned to the channels for supplying fuel and/or lubricant and/or coolant forming channels that extend through the transmission unit for supplying fuel and/or lubricant and/or coolant when the base transmission case and the unitary case are joined.
The transmission unit can be a mechanical transmission unit, which means that the speed/torque conversion is achieved solely by means of mechanical transmission elements. It is conceivable, however, that the transmission unit has a combined power transmission. The following embodiments are conceivable, for example:
a) mechanical-hydrodynamic combination transmission
b) mechanical-hydrostatic combination transmission
c) mechanical-electric combination transmission comprising a base transmission disposed between the transmission input shaft and the transmission output shaft and an angular drive that is connected with the output drive of the base transmission in an at least indirect rotation-proof manner.
The angular drive comprises at least one bevel gear step with a first bevel gear and a second bevel gear, where the second bevel gear can be coupled with the transmission output shaft in an at least indirect rotation-proof manner.
The first bevel gear can be connected with the mechanical transmission part in various ways. The following are conceivable methods:
a) coupling with an output drive shaft of the mechanical transmission part
b) coupling with a transmission element of the mechanical transmission part.
The rotation-proof connection can be non-positive and/or positive locking. An embodiment is preferably used where the mechanical transmission part comprises a planetary gear step and where the rotation-proof connection of the first bevel gear is realized with the internal gear acting as a transmission element. Again, the connection can be non-positive and/or positive and/or material-locking. Preferably, however, the first bevel gear and the transmission element of the planetary gear step are configured as an integral unit.
The first bevel gear of the angular drive and a transmission element of the base transmission unit forming the output drive of the base transmission unit are preferably connected in a direct rotation-proof manner and disposed spatially close together.
If the base transmission unit comprises at least one planetary gear set with at least one internal gear, a sun wheel, planetary wheels and a bridge or a spur gear set the output drive of the base transmission unit is formed by an element of the planetary gear set or the spur gear set. According to an especially preferred embodiment, the first bevel gear of the bevel gear step can be coupled with the internal gear of the planetary gear step so as to be rotation-proof.
If the first bevel gear is coupled with an internal gear of the mechanical transmission part in a rotation-proof manner, and if the case has the above described form the first bevel gear can have an especially large diameter, which results in an especially short and compact overall size. The second bevel gear coupled with the output drive shaft is preferably installed and removed via the flanging of the overall angular drive. The angular drive elements are positioned separately from the standardized positioning of the output drive, i.e. the transmission output shaft, which is why the bearings do not have to be readjusted when the angular drive is flangemounted. The cooling devices that are otherwise flange-mounted to the cover of a base transmission with no angular drive can be mounted in the end area of the angular drive. The necessary connecting lines will then not have to be produced with flexible hoses. They can enter the case in the form of channels.
The individual elements of the bevel gear step can be configured with a straight tooth system or a helical tooth system. Preferably, tooth systems are used where the individual tooth element has a constant tooth height. For the configuration with a helical tooth system an involute tooth system is preferably used. The helical tooth system allows an especially quiet operation.
The solution of the invention allows that all angles and output drive torques are covered by one single angular drive case. Due to the diameter-emphasized construction the angular drive is highly compact and short. Maintenance and the assembly and disassembly of the bearing wheels and gears are very easy.