WO2008046423A1

WO2008046423A1 - Arrangement for transmitting torsional forces

Info

Publication number: WO2008046423A1
Application number: PCT/DK2007/000448
Authority: WO
Inventors: Claus Jesper Johansen; Thomas Kirk SØRENSEN; Jan Schenkel HØGH
Original assignee: Sauer-Danfoss Aps
Priority date: 2006-10-18
Filing date: 2007-10-17
Publication date: 2008-04-24
Also published as: DE102006050242A1

Abstract

The invention relates to an arrangement for transmitting torsional forces between a first part (11) which has an essentially planar, first bearing face, and a second part (12) which has an essentially planar, second bearing face (25) against which the first bearing face bears, wherein the two bearing faces are arranged essentially transversely with respect to a torsional axis and are connected to one another in a rotationally fixed fashion. In order to provide an arrangement which is of simple design and can be manufactured cost-effectively, the two parts (11, 12) are connected to one another in a rotationally fixed fashion by means of positively locking elements (41 - 44) which are held under prestress in, in each case, one positively locking element receptacle space of the first part (11) and in, in each case, one positively locking element receptacle space of the second part (12).

Description

Arrangement for transmitting torsional forces

The invention relates to an arrangement for transmitting torsional forces between a first part, which has a substantially planar first contact surface, and a second part, which has a substantially planar second contact surface, against which the first contact surface bears, wherein the two contact surfaces arranged substantially transversely to a torsion axis and rotatably connected to each other. The invention further relates to a hydraulic machine, in particular a gear machine or a rotary piston machine, the positive displacement type, with a previously described arrangement for transmitting torsional forces.

German Patent DE 26 14 471 C2 and US Pat. No. 3,289,602 belonging to the same patent family disclose a rotary piston machine with a displacer unit formed from an internally toothed fixed stator and an externally toothed rotor. The displacer unit is housed in a pump housing comprising a pump cover. The pump cover is fastened to the pump housing together with the stator and a control plate by means of screws.

The object of the invention is to provide an arrangement according to the preamble of claim 1, which is simple in construction and inexpensive to produce.

The object is in an arrangement for transmitting torsional forces between a first part, which has a substantially planar first Ania- gefläche, and a second part, which has a substantially flat second contact surface, against which the first contact surface, wherein the two Arranged contact surfaces substantially transverse to a torsion axis and rotatably connected to each other, characterized solves that the two parts are rotatably connected to each other by form-fitting elements which are received under bias in each case a positive locking element receiving space of the first part and in each case a positive locking element receiving space of the second part. The prestressed positive locking elements serve to transmit torsional forces between the first and the second housing part. The interlocking elements are advantageously dimensioned and designed such that the pretensioning of the interlocking elements is sufficient to transmit the torsional forces without the interlocking elements being deformed.

A preferred embodiment of the arrangement is characterized in that the positive-locking elements are formed by spring pins. The spring pins are resiliently biased biased arranged in the associated form-fitting element receiving spaces. The form-fitting element receiving spaces are blind holes or through-holes in the associated parts.

A further preferred exemplary embodiment of the arrangement is characterized in that the spring pins each have essentially the shape of a straight circular cylinder jacket with a slot extending in the longitudinal direction. Preferably, the spring pins are made in one piece.

A further preferred embodiment of the arrangement is characterized in that the positive-locking elements are biased in the radial direction. The spring pins have a larger diameter when not installed than in the installed, prestressed state.

A further preferred embodiment of the arrangement is characterized in that the positive-locking elements each have a continuous cavity in the axial direction. The cavities extend preferably parallel to the torsion axis. The continuous cavities serve to carry fasteners.

A further preferred embodiment of the arrangement is characterized in that the two parts are held by fasteners with their contact surfaces in abutment against each other. The fastening elements are, for example, fastening screws, by means of which the two parts are held together in the axial direction, that is to say parallel to the torsion axis.

A further preferred embodiment of the arrangement is characterized in that the fastening element comprise screws. The fastening elements preferably extend through through holes in one of the parts and are screwed into blind holes in the other part.

A further preferred exemplary embodiment of the arrangement is characterized in that at least one fastening element extends through a positive-locking element. This has the advantage that only one blind hole and / or through hole in the associated part is required for the fastening element and the associated positive-locking element.

A further preferred embodiment of the arrangement is characterized in that the at least one fastening element and the associated positive-locking element are partially arranged in a common through-hole. The through hole serves on the one hand for receiving one end of the associated positive-locking element. In addition, the through hole serves to pass through the associated fastening element.

A further preferred exemplary embodiment of the arrangement is characterized in that a plurality, in particular all fastening elements extend through in each case one positive-locking element. There- by a stable, space-saving attachment of the parts together.

Another preferred exemplary embodiment of the arrangement is characterized in that at least one further part is held in contact with the first or the second part by the fastening elements. For this purpose, a further contact surface is provided on the first or the second part, at which a further contact surface of the further part comes to rest.

A further preferred embodiment of the arrangement is characterized in that at least one of the parts in the associated contact surface has at least one recess for a sealing element. The sealing element is used to seal a preferably surrounded by the sealing element recess to the environment.

A further preferred embodiment of the arrangement is characterized in that at least two positive locking elements are provided. Due to the at least two positive locking elements, a stable rotationally fixed connection of the two parts is made possible relative to each other.

A further preferred embodiment of the arrangement is characterized in that at least three interlocking elements are arranged distributed uniformly in the circumferential direction. This will ensure that the two parts maintain their relative position to each other in transmitting torsional forces.

The distribution of the form-locking elements in the circumferential direction does not have to be quite uniform. Due to the number of teeth, the hydraulic machine may have an odd number of screw holes. If fewer pins or positive locking elements are used it is not always possible to distribute them evenly over the circumference.

The above object is achieved in a hydraulic machine, in particular a gear machine or a rotary piston machine, the positive displacement type, by a previously described arrangement for transmitting torsional forces. The hydraulic machine serves to provide a torque and a rotational speed at an output shaft.

A preferred embodiment of the hydraulic machine is characterized in that the parts of housing parts of the hydraulic machine are formed. The parts are, for example, a housing base and a ring gear of a gear machine, which is also referred to as a stator.

A further preferred embodiment of the hydraulic machine is characterized in that one of the housing parts comprises an internally toothed stator. In the stationary internally toothed stator, an externally toothed rotor is rotatably arranged.

A further preferred embodiment of the hydraulic machine is characterized in that one of the housing parts comprises a fastening flange. The mounting flange is preferably for attaching the hydraulic machine to a functional device, such as a construction machine, which is driven by the hydraulic machine.

A further preferred embodiment of the hydraulic machine is characterized in that further housing parts are held by means of the fastening elements on one of the housing parts. The other housing parts are, for example, a control or channel plate or a housing cover. In particular, the invention relates to a hydraulic machine used, for example, as a drive motor on individual wheels of a construction machine. The invention is particularly directed to positive displacement hydraulic pumps and motors, preferably to gear machines having five intermeshing tooth elements.

In arrangements and machines of the type described above, there are usually high demands on the accuracy of fit of the parts to each other. In particular, slippage between mutually fixed parts must be avoided in order to preserve the life of the machine or arrangement. Therefore, torsional forces are transmitted between the parts in conventional machines and arrangements by friction. For this purpose, the two parts can be braced against each other by screw. However, the relatively high torsional forces and the relatively low coefficient of friction, for example about 0.1, of 5, mean that the threaded connections must be relatively large in size and dimensioned. Among other things, this leads to increased stresses being applied to the parts as a result of the screw connections. This can affect free spaces between moving and fixed parts. Free spaces are usually provided with tight tolerances because they have a direct influence on, for example, hydraulic losses in a hydraulic machine. The demands on the manufacturing tolerances are increased by the tension caused by the screw connections. This makes the production more expensive.

According to one essential aspect of the invention, the requirements for the manufacturing tolerances can be reduced by the prestressed positive locking elements. At the same time, a better control over the size of free spaces in the parts is made possible.

Further advantages, features and details of the invention will become apparent from the following description, in which reference is made to the Drawing various embodiments are described in detail. Show it:

Figure 1 is a perspective view of a hydraulic machine;

Figure 2 is a front view of the hydraulic machine of Figure 1;

Figure 3 is a perspective view of three parts of the hydraulic machine of Figures 1 and 2;

Figure 4 shows the hydraulic machine of Figures 1 to 3 in longitudinal section;

FIG. 5 shows a form-locking element in plan view;

FIG. 6 shows the positive-locking element from FIG. 5 in a side view and FIG

Figure 7 is a force-displacement diagram with two different spring characteristics.

In the figures 1 to 4, an arrangement 1 is shown in different views. In the arrangement 1 is a hydraulic machine, which is also referred to as a gear machine or rotary piston machine. The hydraulic machine, which may be designed as a hydraulic pump or hydraulic motor, comprises a housing 2 with two hydraulic connection points 3, 4. The hydraulic connection point 3 is, for example, a pressure connection point, via which the hydraulic machine 1 is pressurized supplied hydraulic medium, such as hydraulic oil, is supplied. The hydraulic medium is discharged via the hydraulic connection point 4, for example. The housing 2 is provided with a mounting flange 5 having a plurality of through holes for passing through fasteners. The mounting flange or mounting flange 5 serves to releasably secure the hydraulic machine 1, for example, to a construction machine. Through the mounting flange 5, an output shaft 6 projects out of the housing 2. By an arrow 8 is indicated that the output shaft 6 outputs a torque. The torque 8 is generated in the hydraulic machine 1, which is also referred to as a hydraulic motor, from hydraulic energy. In this case, the hydraulic medium drives displacement elements, such as gears, vanes, pistons, in the housing 2. An arrow 9 indicates that the torque 8 on the output shaft 6 counteracts a torque acting in the opposite direction of the housing 2.

In Figure 2 it can be seen that the mounting flange 5 is integrally connected to a first housing part 11. The first housing part 11 is a housing base body through which the output shaft 6 extends. On the first housing part 11, a second housing part 12, a third housing part 13 and a fourth housing part 14 are attached. The first housing part 11 has a substantially planar contact surface or mounting surface, which in a first mounting plane 21 on a substantially planar contact surface of the second housing part

12 is present.

The second housing part 12 has a further substantially planar contact surface on which in a second mounting plane 22, a substantially planar mounting surface or contact surface of the third housing part

13 is present. The third housing part 13 has a further substantially planar contact surface on which a substantially planar contact surface of the fourth housing part 14 rests in a third mounting plane 23. In the second housing part 12 is a sprocket with an internal toothing. The third housing part 13 is a Channel plate comprising a plurality of channels through which the hydraulic medium, which is also referred to as a hydraulic medium, from the hydraulic connection points 3, 4 passes to the housing parts 11, 12. The fourth housing part 14 is a housing cover, which is equipped with the hydraulic connection points 3, 4. The three mounting planes 21 to 23 are arranged parallel to each other.

In the first mounting plane 21, the reaction torque occurring during operation of the hydraulic machine 1 is transmitted. The additional mounting planes 22, 23 only have to be sealed against internal hydraulic pressure. The mounting plane 21, which is also referred to as a mounting surface, as well as the mounting planes 22, 23, which are also referred to as mounting surfaces, must also be sealed against the hydraulic pressure.

In FIG. 3, the essentially planar contact surface of the second housing part 12 is designated by 25. The flat Anlagef pool 25 is arranged in the assembled state of the hydraulic machine 1 in the first mounting plane 21. In the contact surface 25 a plurality of recesses is provided. A plurality of rollers 26, 27 serve to form an internal toothing on the second housing part 12. The internal toothing of the second housing part 12, which is also referred to as a ring gear, is in engagement with an external toothing of an inner gear 29. The inner gear 29 is also referred to as a rotor. Similarly, the ring gear 12 is also referred to as a stator. By different numbers of teeth between the rotor and stator is achieved that the rotor can rotate eccentrically in the stator. Normally, the rotor has one less tooth than the stator.

The stator 12 is, as will be described below, rotatably connected to the first housing part 11. The rotor 29 is coupled to the output shaft 6, for example, by a further toothing. By the engagement of the external toothing of the rotor 29 in the internal toothing of the Stators 12, a number of cavities is formed. During rotation of the rotor 29 relative to the stator 12, the volumes of the individual cavities increase and decrease cyclically. By a predetermined pressure gradient between the hydraulic connection points 3, 4, the rotor 29 is excited to rotate.

In addition, 25 through-holes 31, 32 are recessed in the contact surface. The through holes 31, 32 serve, as will be described below, for receiving form-fitting elements and for passing through fastening elements. By an arrow 34, the radius of a pitch circle is indicated, on which the through holes 31, 32 are arranged. By a further arrow 35, the force is indicated, which is exerted in the mounted state of the hydraulic machine 1 of the contact surface 25 of the second housing part 12 on the abutting contact surface of the first housing part 11. By a further arrow 36, the associated friction force is indicated. The frictional force acts in the tangential direction and is therefore also called a tangential force. According to an essential aspect of the present invention, the reaction torque is not transmitted by friction.

4, four positive locking elements 41 to 44 are indicated by dashed lines, which serve to transmit the torque or reaction torque between the two housing parts 11, 12. The positive-locking elements 41 to 44 are spring pins.

In Figures 5 and 6, the spring pin 41 is shown alone in different views. The spring pin 41 comprises a circular cylinder jacket-shaped pin body 65, which has a longitudinal slot 66. One end of the spring pin 41 is provided with a chamfer 67. In Figure 6 it can be seen that the spring pin 41 is C-shaped. In its interior, the spring pin 41 has a longitudinally continuous cavity 68. In the first housing part 11, a blind hole 45 for screwing in a fastening screw 51 to 54 is provided in each case. In extension of the blind hole 45 four through holes 46, 47 and 48 are provided in the housing parts 12, 13 respectively. In one part of the blind hole 45, one end of the positive locking element 42 is received. The other end of the interlocking element 42 is received in a part of the through hole 46 of the housing part 12. The two ends of the positive-locking element 42 are received under prestress in the associated holes 45, 46.

The interlocking elements or spring pins 41 to 44 serve to transmit the reaction torque occurring during operation of the hydraulic machine 1 between the housing parts 11 and 12. Through the cavities in the spring pins 41 to 44, a screw 51 to 54 is guided in each case. The screws 51 to 54 each have a shaft 60 whose outside diameter is slightly smaller than the inside diameter of the associated spring pin 41 to 44. The screws 51 to 54 each have a head 61, which rests against the housing cover 14. The shaft 60 is provided at its free end 62 with a thread which is screwed into a complementarily formed thread in the associated blind hole in the housing part 11.

FIG. 7 shows in a diagram the spring force F over the spring travel f for different spring characteristics 71, 72. The dashed lines spring characteristic 71 belongs to a solid, non-resilient pin, as it can be used to the two housing parts 11, 12 rotatably connected to each other. The spring characteristic 72 belongs to a resiliently biased and installed in the prestressed spring pin, as it is indicated in Figure 4 with 41 to 44.

FIG. 7 shows that the spring pin has the advantage, in comparison with a solid or non-resilient pin, that the prestressed spring pin with the spring characteristic curve 72 causes much less movement of the parts 11, 12. lative to each other as a massive pen. The two housing parts 11, 12 of the hydraulic machine 1 shown in Figure 4 are rotatably connected by a total of nine spring pins together, of which only four are shown.

Claims

claims

An arrangement for transmitting torsional forces between a first part (11) having a substantially planar first abutment surface and a second part (12) having a substantially planar second abutment surface (25) against which the first one Bearing surface abuts, wherein the two contact surfaces arranged substantially transversely to a torsion axis and rotatably connected to each other, characterized in that the two parts (11, 12) by positive locking elements (41- 44), the under bias in each one Formschlusselementaufnah- meraum the first part (11) and in each case a positive locking element receiving space of the second part (12) are received, rotatably connected to each other.

2. Arrangement according to claim 1, characterized in that the positive-locking elements (41-44) are formed by spring pins.

3. Arrangement according to claim 2, characterized in that the spring pins (41-44) each have substantially the shape of a straight circular cylinder jacket having a longitudinally extending slot.

4. Arrangement according to one of the preceding claims, character- ized in that the positive-locking elements (41-44) are biased in the radial direction.

5. Arrangement according to one of the preceding claims, characterized in that the positive-locking elements (41-44) each have an axially continuous cavity (68).

6. Arrangement according to one of the preceding claims, characterized in that the two parts are held by fastening elements (51-54) with their contact surfaces in abutment against each other.

7. Arrangement according to claim 6, characterized in that the fastening elements (51-54) comprise screws.

8. Arrangement according to claim 6 or 7, characterized in that at least one fastening element (51-54) by a form-fitting

5 element (41-44) extends therethrough.

9. Arrangement according to claim 8, characterized in that the at least one fastening element (51-54) and the associated positive-locking element (41-44) are partially arranged in a common through hole. 0

10. Arrangement according to one of claims 6 to 9, characterized in that a plurality, in particular all fastening elements (51-54) extend through in each case a positive-locking element (41-44) therethrough.

11. Arrangement according to one of claims 6 to 10, characterized marked 5 records that at least one further part (13,41) held by the fastening elements (51-52) in contact with the first or the second part (11, 12) is.

12. Arrangement according to one of the preceding claims, characterized in that at least one of the parts (11-14) in the zugehö ri- o gene contact surface has at least one recess for a sealing element.

13. Arrangement according to one of the preceding claims, characterized in that at least two positive locking elements (41-44) are provided. 5

14. Arrangement according to one of the preceding claims, characterized in that at least three positive locking elements (41-44) are arranged in the circumferential direction in particular evenly distributed.

15. Hydraulic machine, in particular gear machine or rotary piston machine, the positive displacement type, with an arrangement for transmitting torsional forces according to one of the preceding claims.

16. Hydraulic machine according to claim 15, characterized in that the parts (11-14) are formed by housing parts of the hydraulic machine.

17. Hydraulic machine according to claim 16, characterized in that one of the housing parts (12) comprises an internally toothed stator.

18. Hydraulic machine according to claim 16 or 17, characterized in that one of the housing parts (11) comprises a fastening flange (5).

19. Hydraulic machine according to one of claims 16 to 18, characterized in that further housing parts (13,14) by means of the fastening elements (51, 54) are held on one of the housing parts.