Axial piston machine

Abstract

An axial piston machine may include a rotor rotatably mounted in a housing. A plurality of cylinders may be arranged in a ring around the rotor. A plurality of pistons may each be arranged within each of the plurality of cylinders and may be constructed and arranged to selectively translate within the plurality of cylinders. A plurality of inlet openings may be defined in a cylinder head and at least one outlet opening may be defined in the housing. The plurality of cylinders may be in operative communication with the plurality of inlet openings and the at least one outlet opening. An inlet channel may be defined in the cylinder head and may extend to each of the plurality of inlet openings. An outlet channel may be defined in the housing and may be in operative communication with the at least one outlet opening. A bypass channel may be defined in the housing and may extend from the cylinder head into one of the outlet channel or a swashplate space. A bypass valve may be connected to the cylinder head or may be integrated with the cylinder head. The bypass valve may be constructed and arranged to selectively apportion a working medium to the inlet channel and the bypass channel based on a switching position of the bypass valve.

Claims

1. An axial piston machine comprising: a housing; a cylinder head; a rotor rotatably mounted in the housing; a plurality of cylinders arranged in a ring around the rotor; a plurality of pistons each arranged within a respective one of the plurality of cylinders and configured to selectively translate therein; a plurality of inlet openings defined in the cylinder head, each of the plurality of inlet openings in operative communication with an associated one of the plurality of cylinders; a plurality of outlet openings defined in the housing, each of the plurality of outlet openings in operative communication with an associated one of the plurality of cylinders; an inlet channel defined in the cylinder head, the inlet channel selectively in fluid communication with the plurality of inlet openings; an outlet channel defined in the housing in operative communication with the plurality of outlet openings; a bypass channel defined at least partially within the housing extending from the cylinder head into the outlet channel; a bypass valve connected to the cylinder head; and wherein the bypass valve is structured and arranged to selectively apportion a working medium to the inlet channel and the bypass channel based on a switching position of the bypass valve.

2. The axial piston machine according to claim 1, wherein the bypass valve is secured to an outside surface of the cylinder head via a thermal decoupling material.

3. The axial piston machine according to claim 2, wherein the thermal decoupling material is an elastomer body.

4. The axial piston machine according to claim 1, further comprising a braking device disposed within the cylinder head, wherein: the braking device is structured and arranged to brake the rotor when actuated; and the braking device is actuatable via at least one of the working medium and a compressed air.

5. The axial piston machine according to claim 4, further comprising a braking channel defined in the cylinder head, wherein a first end of the braking channel is connected to the bypass valve and a second end of the braking channel is connected to the braking device such that the braking channel facilitates actuation of the braking device via the bypass valve.

6. The axial piston machine according to claim 4, further comprising a rotary valve disk connected in a torque-proof manner to the rotor, wherein: the rotary valve disk includes an opening; the braking device is structured and arranged to secure the rotor in a defined rotational position; and when the rotor is in the defined rotational position, the opening of the rotary valve disk is aligned with an inlet opening of the plurality of inlet openings that is in operative communication with a cylinder of the plurality of cylinders in which a piston of the plurality of pistons is disposed in an area of an upper dead point.

7. The axial piston machine according to claim 6, wherein: the braking device includes a pin structured and arranged to engage a recess defined on the rotary valve disk; and the pin engages the recess when the rotor is in the defined rotational position securing the rotor in the defined rotational position.

8. The axial piston machine according to claim 1, further comprising: a connecting channel extending between and connecting the inlet channel and the bypass channel; and an overpressure valve disposed within the connecting channel.

9. The axial piston machine according to claim 1, wherein the bypass channel is defined at right angles in relation to an external surface of at least one of the cylinder head and the housing.

10. A heat recovery system in a motor vehicle with the axial piston machine according to claim 1.

11. The axial piston machine according to claim 1, wherein the bypass valve is integrated within the cylinder head.

12. The axial piston machine according to claim 1, further comprising a starter channel defined in the cylinder head operatively connected to an output side of at least one of the plurality of cylinders, wherein the starter channel includes a valve disposed on an input side of at least one of the plurality of cylinders.

13. The axial piston machine according to claim 1, wherein: the bypass channel further extends through the cylinder head to the bypass valve; and the inlet channel is connected to the bypass valve such that the bypass valve is selectively in fluid communication with the plurality of inlet openings via the inlet channel.

14. The axial piston machine according to claim 1, wherein: the plurality of cylinders extend through a surface of the housing; and the cylinder head is arranged on and coupled to the surface of the housing.

15. The axial piston machine according to claim 14, wherein: the bypass channel extends to the outlet channel; a first portion of the bypass channel is disposed completely within and defined by the housing, the first portion of the bypass channel extending from the surface of the housing to the outlet channel; and a second portion of the bypass channel is disposed completely within and defined by the cylinder head, the second portion of the bypass channel connected to the first portion of the bypass channel in a region of the surface of the housing.

16. The axial piston machine according to claim 15, wherein the second portion of the bypass channel extends within the cylinder head from a surface of the cylinder head facing the housing to a side surface of the cylinder head on which the bypass valve is arranged.

17. The axial piston machine according to claim 15, wherein: the first portion of the bypass channel is disposed radially outside of the plurality of cylinders relative to the rotor; and the first portion of the bypass channel, at least partially, extends within the housing in an axial direction of the plurality of cylinders.

18. An axial piston machine comprising: a housing; a cylinder head coupled to a surface of the housing; a rotor rotatably mounted in the housing; a plurality of cylinders arranged within the housing in a ring around the rotor and extending through the surface of the housing; a plurality of pistons each arranged within a respective one of the plurality of cylinders and configured to selectively translate therein; a plurality of inlet openings defined in the cylinder head, each of the plurality of inlet openings in operative communication with an associated one of the plurality of cylinders; a plurality of outlet openings defined in the housing, each of the plurality of outlet openings in operative communication with an associated one of the plurality of cylinders; an inlet channel defined in the cylinder head, the inlet channel selectively in fluid communication with the plurality of inlet openings; an outlet channel defined in the housing in operative communication with the plurality of outlet openings; a bypass valve connected to the cylinder head; a bypass channel extending from the bypass valve to the outlet channel, the bypass channel disposed completely within the housing and the cylinder head; and wherein the bypass valve is structured and arranged to selectively apportion a working medium to the inlet channel and the bypass channel based on a switching position of the bypass valve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In a schematic representation, not to scale:

(2) FIG. 1 shows a sectional view through an axial piston machine according to a first embodiment;

(3) FIG. 2 shows a view as in FIG. 1 but with a bypass valve integrated in a cylinder head of the axial piston machine;

(4) FIG. 3 shows a view as in FIG. 1 but with a connecting channel between the bypass channel and an inlet channel;

(5) FIG. 4 shows a view according to the second alternative with a bypass channel opening into a swashplate space;

(6) FIG. 5 shows a view similar to FIG. 2 but with a starter channel.

DETAILED DESCRIPTION

(7) According to FIGS. 1 to 5, an axial piston machine 1 according to the invention which for example can be part of a heat recovery system 2 not explained in detail in a motor vehicle, comprises a rotor 4 mounted rotatably in a housing 3. Cylinders 5 are arranged in a ring around and parallel to the rotor 4 in the housing 3, in which pistons 6 are mounted in a translationally adjustable manner. Each piston 6 is firmly connected to a sliding foot 27 which in turn is coupled to a swashplate via a sliding block. Each cylinder 5 is assigned an inlet opening 8 in a cylinder head 7 and an outlet opening 9 in the housing 3. Towards the top the cylinder head 7 is terminated by means of a cover 10. According to the invention, an inlet channel 11 leading to the inlet opening 5 is now provided in the cylinder head 7 and an outlet channel 12 connected in a communicating manner to the outlet opening 9 is provided in the housing 3. Also provided is a bypass channel 13 which extends from the cylinder head 7 via the housing 3 as far as the outlet channel 12 (FIGS. 1 to 3 and 5) or as far as into a swashplate space 24 (cf. FIG. 4). Furthermore, a bypass valve 14 is provided according to the invention which is connected to the cylinder head 7 according to FIGS. 1 and 3, i.e. is fastened to the outside of this and which according to FIG. 2 is integrated in the cylinder head 7. The bypass valve 14 apportions an inflow of working medium to the inlet channel 11 and the bypass channel 13 depending on its switching position.

(8) By integrating the bypass channel 13 in the cylinder head 7 and the housing 3, this can be arranged in a manner optimized in terms of installation space, wherein at the same time further components such as for example lines and branches as would be necessary in external bypass channels known from the prior art can be omitted.

(9) If FIGS. 1, 3 and 4 are considered, it can be seen that the bypass valve 14 is fastened to the outside of the cylinder head 7 via a decoupling element 15. The decoupling element 15 is used in particular for thermal decoupling of the bypass valve 14 from the cylinder head 7 and can for example be configured as an elastomer element and/or a thermal decoupling material.

(10) If FIG. 2 is considered, a braking device 16 for braking the rotor 4 can be additionally seen which can be actuated by means of the working medium, i.e. via the bypass valve 14 or purely theoretically by means of compressed air. For this purpose a braking channel 17 is provided in the cylinder head 7 which is connected at one end to the bypass valve 14 and at the other end to the braking device 16 so that the braking device 16 can be actuated by means of the bypass valve 14. The braking device 16 is here configured in such a manner that it fixes the rotor 4 in a defined rotational position in which an opening 18 of a rotary valve disk 19 connected in a torque-proof manner to the rotor 4 is in alignment with an inlet opening 8 of a cylinder 5 wherein the piston 6 of this cylinder 5 is located in the area of an upper dead point. As a result, the rotor 4 can be stopped in a rotational angular position in which it can easily start running by application with vapour since the inlet aperture releases the working chamber and the piston 6 can be set in motion by gentle application of pressure. For this purpose the braking device 16 can comprise a pin 20 which in the defined rotational position engages in a recess arranged at the edge on the rotary valve disk 19 and thereby fixes the rotary valve disk 19 in the desired predefined rotational position. Naturally the braking device 16 can for example also comprise a brake shoe or a brake pad which acts on the rotary valve disk 19 or on another part rotating with the rotor 4. Purely theoretically a braking action can also be brought about without the braking device 16 if the bypass valve 14 specifically switches a counterpressure when the respective piston 6 in the outlet opening 9 of which air?? is blown in, rests at the lower dead point (cf. left piston in FIGS. 1 to 3). In this case, the rotary valve disk 19 would close the inlet opening 8 so that when working medium flows into the cylinder 5 via the outlet opening 9, an upward travel of the piston 6 and therefore a rotational movement of the rotor 4 would be braked.

(11) In the axial piston machine according to FIGS. 3 and 4, a connecting channel 21 is provided between the inlet channel 11 and the bypass channel 13 in which an overpressure valve 22 is arranged. This overpressure valve 22 opens as soon as a predefined limiting pressure of the working medium is exceeded whereupon the working medium blows out into the bypass channel 13 via the connecting channel 21. As a result, the axial piston machine 1 can be shut down until a subcritical pressure at which the overpressure valve 22 does not respond is present without the bypass valve 14 itself needing to be switched for this purpose. This enables a particularly rapid switching which is particularly advantageous in the so-called failsafe case.

(12) If the embodiment of the axial piston machine 1 according to FIG. 4 is observed, it can be seen that the bypass channel 13 opens into the swashplate space 24 and has a nozzle 25 at its end facing the swashplate space 24. This is directed towards an impact surface 26 of the sliding foot 27 connected to the piston 6 and thus serves as a starting aid whereby a vapour jet emerging therefrom presses the piston 6 downwards. When starting the axial piston machine 1, a translational starting impulse can be applied to the sliding foot 27 and a rotational starting impulse can be applied to the swashplate 23 via the nozzle 25.

(13) If the embodiment of the axial piston machine 1 according to FIG. 5 is considered, it can be seen that in this a starter channel 28 is provided in the cylinder head 7 which is connected to the cylinder 5 on the output side and has a valve 29 on the input side which can be configured separately from the bypass valve 14 or as part of the same. A translational starting impulse can be applied to the piston 6 via the starter channel 28. An overpressure valve 22 could be arranged in the bypass channel 13 in similar manner to FIGS. 3, 4.

(14) With the axial piston machine 1 according to the invention, not only an arrangement of the bypass channel 13 in the cylinder head 7 or in the housing 3 which is optimized in terms of installation space is possible but the bypass channel 13 enables a media guidance comparatively close to real operation without the axial piston machine 1 being actuated.

(15) Thus, for example, it is possible to separate lubricant contained in the working medium as is already provided in active operation. As a result, the axial piston machine 1 can be optimally lubricated when restarting, in particular lubrication of the swashplate 23 is possible. As a result of the bypass channel 13 being guided through the housing 3, a more rapid heating of the housing 3 can be achieved.

(16) If the bypass valve 14 is attached to the outside of the cylinder head 7 as shown according to FIGS. 1, 3 and 4, a comparatively high modularity or flexibility can be achieved since the axial piston machine 1 can be used purely theoretically even without the bypass valve 14. By integrating the same in the cylinder head 7, however an extremely compact design can be achieved.