Hydraulic Transformer

Abstract

The hydraulic transformer (1) includes a housing (2) having a high-pressure connection (3), a low-pressure connection (4), and an operating pressure connection (5), and a barrel member (19, 20) rotatably mounted within the housing (2), the barrel (19, 20) having a plurality of compression chambers whose volumes change in response to rotation of the barrel member (19, 20). A rear surface (24) of the barrel member (19, 20) has a plurality of barrel ports (27) communicating with each of the compression chambers. The hydraulic transformer (1) includes faceplates (28, 29) supported by the housing (2), the faceplates (28, 29) having a front surface (30) supporting the rear surface (24) of the barrel member (19, 20), a rear surface (31) facing the housing (2), a circumferential outer wall, and a central bore (49) surrounded by a circumferential inner wall. The faceplates (28, 29) are rotatable within a predetermined angle relative to the housing (2), and the front surface (30) is provided with three arc-shaped faceplate ports, and the barrel ports (27) move along the three arc-shaped faceplate ports in response to rotation of the barrel members (19, 20). The faceplate ports communicate with the high-pressure connection (3) through a first passage (35) in the faceplates (28, 29), the low-pressure connection (4) through a second passage (36) in the faceplates (28, 29), and the operating pressure connection (5) through a third passage (37) in the faceplates (28, 29), respectively. One of the first to third passages (35, 36, 37) has an opening at the back surface (31) of the face plate (28, 29), one of the first to third passages (35, 36, 37) has an opening at the outer circumferential wall of the face plate (28, 29), and one of the first to third passages (35, 36, 37) has an opening at the inner circumferential wall of the face plate (28, 29).

Description

[Technical Field]

[0001] The present invention relates to a hydraulic transformer comprising: a housing having a high-pressure connection, a low-pressure connection, and an operating pressure connection; and a barrel member rotatably mounted within the housing, the barrel member having a plurality of compression chambers whose volumes change in response to rotation of the barrel member, the rear surface of the barrel member having a plurality of barrel ports communicating with each of the compression chambers and a face plate supported by the housing. the faceplate having a front surface supporting the back surface of the barrel member, a back surface facing the housing, a circumferential outer wall, and a central hole surrounded by a circumferential inner wall, the faceplate being rotatable within a predetermined angle relative to the housing, wherein the front surface is provided with three arc-shaped faceplate ports, and the plurality of barrel ports move along the three arc-shaped faceplate ports in response to rotation of the barrel member, and the three arc-shaped faceplate ports respectively communicate with the high-pressure connection through a first passage in the faceplate, the low-pressure connection through a second passage in the faceplate, and the working pressure connection through a third passage in the faceplate. [Background technology]

[0002] Such a hydraulic transformer is disclosed in Dutch Patent Publication No. NL1019736. Known hydraulic transformers have advantages in terms of friction, but have a relatively narrow operating range. The high-pressure and low-pressure connections can be fluidly connected to high-pressure and low-pressure lines of a common pressure rail system, while the operating pressure connection can be fluidly connected to a load, such as a hydraulic cylinder or a motor. A general advantage of hydraulic transformers is that, unlike throttling, they operate in a non-dissipative manner. Energy can be recovered and supplied to other loads, for example by being stored in a hydropneumatic accumulator. Summary of the Invention [Problem to be solved by the invention]

[0003] SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved hydraulic transformer. [Means for solving the problem]

[0004] This object is achieved by a hydraulic transformer according to the present invention, which is characterized in that one of the first to third passages has an opening at the back surface of the face plate, one of the first to third passages has an opening at the outer circumferential wall of the face plate, and one of the first to third passages has an opening at the inner circumferential wall of the face plate.

[0005] An advantage of the hydraulic transformer according to the present invention is that the first to third passages have respective openings on different sides of the front faceplate, thereby providing the opportunity to rotate the faceplate through relatively large angles relative to the housing without risk of short circuiting between the respective openings, thereby providing the hydraulic transformer with a wide operating range.

[0006] In a particular embodiment, the hydraulic transformer comprises a main shaft through which the barrel member is rotatable relative to the housing, the main shaft being mounted within the housing and rotatable about a first axis of rotation, wherein the main shaft has a flange extending perpendicular to the first axis of rotation, and a plurality of pistons having individual spherical piston heads fixed to the flange at equal angular intervals around the first axis of rotation and having centerlines parallel to the first axis of rotation, wherein the barrel member comprises a plurality of independent sleeves within which the individual pistons are movable, thus forming the compression chambers, wherein a bearing surface of the barrel member opposite to a back surface of the barrel member supports a sleeve bottom of the sleeve, and wherein, in response to rotation of the main shaft and the barrel member comprising the sleeve, each of the pistons reaches a bottom dead centre and a top dead centre relative to the associated sleeve. The barrel member with the sleeve is rotatable about a second axis of rotation that intersects the first axis of rotation at an acute angle so as to move between a first center and a second center, and the barrel ports communicate with the individual compression chambers through barrel member passages in the barrel member and through holes in the bottom of the sleeve. In this embodiment, the hydraulic transformer operates according to the so-called "floating cup principle," which has minimal friction.

[0007] The central hole in the faceplate may be a through-hole, allowing it to be fluidly connected to adjacent channels through openings on both the front and back surfaces of the faceplate.

[0008] In one embodiment, the first passage has an opening at the rear surface of the faceplate, the second passage has an opening at the outer circumferential wall of the faceplate, and the third passage has an opening at the inner circumferential wall of the faceplate, such that the opening at the rear surface of the faceplate is fluidly connected to the high pressure connection, the opening at the outer circumferential wall of the faceplate is fluidly connected to the low pressure connection, and the opening at the inner circumferential wall of the faceplate is fluidly connected to the actuation pressure connection.

[0009] Preferably, the opening in the rear surface of the faceplate is aligned with the associated faceplate port and preferably has substantially the same shape and size as the associated faceplate port because this minimizes pressure field differences on opposite sides of the faceplate, which in turn minimizes friction between the faceplate and one of the barrel member and the housing. As a result, rotation of the faceplate relative to the housing requires a relatively low force.

[0010] In one embodiment, one of the first through third passages having an opening in the circumferential outer wall of the faceplate also has an opening in the rear surface of the faceplate that is aligned with the associated faceplate port and closed by the inner wall of the housing, and preferably has substantially the same shape and dimensions as the associated faceplate port. This minimizes the pressure field difference between the corresponding faceplate port on the front surface and the opening on the rear surface of the faceplate. Note that in an operating condition, no hydraulic fluid flows, or there is only minimal leakage, through the opening on the rear surface of the faceplate.

[0011] Similarly, in one embodiment, one of the first through third passages having an opening in the inner wall of the faceplate also has an opening in the rear surface of the faceplate that aligns with the associated faceplate port, is closed by the inner wall of the housing, and preferably has substantially the same shape and dimensions as the associated faceplate port. This minimizes the pressure field difference between the corresponding faceplate port on the front surface and the opening on the rear surface of the faceplate. Note that in an operating state, no hydraulic fluid flows, or there is only minimal leakage, through the opening on the rear surface of the faceplate.

[0012] The main shaft may be hollow, the interior space of which communicates with the central bore of the face plate through a central bore in the barrel member. Preferably, one of the central bore of the barrel member and the main shaft is provided with an inner sleeve having a spherical outer surface, and the other of the central bore of the barrel member and the main shaft is provided with an outer sleeve having a cylindrical inner surface that fits around the spherical outer surface of the inner sleeve. This allows the central bore to be fluidly connected to a channel even at a position away from the face plate facing away from its front surface. The cooperating inner and outer sleeves can form a sealed connection between the central bore of the barrel member and the interior space of the main shaft.

[0013] In one embodiment, the arc length of the faceplate port communicating with the high pressure connection is greater than the arc length of the faceplate port communicating with the low pressure connection and greater than the arc length of the faceplate port communicating with the working pressure connection, thereby providing an opportunity for a wide operating range.

[0014] The arc length of the faceplate port in communication with the actuation pressure connection may be less than the arc length of the faceplate port in communication with the low pressure connection.

[0015] In one embodiment, in the rotational direction around the second rotation axis, the faceplate ports are separated by individual sealing lands, wherein at least one of the seal lands has a flow-through area that is less than 5% of the flow-through area of ​​the first passage and a through-hole between the front and rear surfaces of the faceplate that widens from the front surface to the rear surface of the faceplate, wherein one of the seal lands preferably has multiple through-holes in the circumferential direction of the faceplate. In an operating state, the relatively small and widening through-holes generate a force on the faceplate that counteracts a pressure field acting on the corresponding seal land on the front surface of the faceplate. This minimizes friction between the faceplate and the housing, thus facilitating rotation of the faceplate. The flow-through area of ​​the through-hole at the front surface of the faceplate may be smaller than the flow-through area of ​​each of the barrel ports that pass through the through-hole.

[0016] The flow-through area at the rear surface of the faceplate may be formed by a pocket. Although the term flow cross-sectional area is used, it should be noted that in an operating condition, no hydraulic fluid flows through the flow cross-sectional area at the rear surface of the faceplate, or only very small leakage occurs. Although the term flow-through area is used, it should be noted that in an operating condition, no hydraulic fluid flows through the flow-through area at the rear surface of the faceplate, or only very small leakage occurs.

[0017] In certain embodiments, the flange comprising the piston is a first flange comprising a first piston, and the main shaft is provided with a second flange extending perpendicular to the first axis of rotation, wherein the hydraulic transformer is provided with a plurality of second pistons comprising individual spherical piston heads, the plurality of second pistons being fixed to the second flange at equal angular intervals around the first axis of rotation and having centerlines parallel to the first axis of rotation, and wherein the barrel member comprising the sleeve comprises a first sleeve. and the plurality of compression chambers are a plurality of first compression chambers, wherein the hydraulic transformer is provided with a plurality of independent second sleeves within which the individual second pistons are movable, wherein the hydraulic transformer is provided with a second barrel member, the second barrel member is rotatable relative to the housing, and is provided with a plurality of independent second sleeves within which the individual second pistons are movable, thus forming individual second compression chambers, wherein the first A bearing surface of the second barrel member opposite to the back surface of the second barrel member supports a sleeve bottom of the second sleeve, and the second barrel member (20) including the second sleeve is rotatable about a third rotation axis intersecting the first rotation axis at an acute angle such that each of the second pistons moves between bottom dead center and top dead center relative to the cooperating second sleeve in response to rotation of the main shaft and the second barrel member (20), and the back surface of the second barrel member is in contact with a barrel member passage in the second barrel member and the second sleeve. and a second barrel port communicating with each of the second compression chambers through a through hole in the bottom of the sleeve of the sleeve, wherein the face plate is a first face plate, and the hydraulic transformer is provided with a second face plate supported by the housing, and is provided with the front surface supporting the back surface of the second barrel member, a back surface facing the housing, a circumferential outer wall, and a central hole surrounded by a circumferential inner wall, and the second face plate is rotatable within a predetermined angle about the third rotation axis relative to the housing;wherein the faceplate port is a first faceplate port, and the front surface of the second faceplate is provided with three arc-shaped second faceplate ports, and the second barrel port moves along the three arc-shaped second faceplate ports in response to the rotation of the main shaft and the second barrel member including the second sleeve, and the second faceplate port is connected to the high pressure connection through a first passage in the second faceplate and to the high pressure connection through a second passage in the second faceplate. and communicates with the low pressure connection through a third passage in the second face plate and with the working pressure connection through a third passage in the second face plate, wherein one of the first to third passages in the second face plate has an opening at the back surface of the second face plate, one of the first to third passages in the second face plate has an opening at the outer circumferential wall of the second face plate, and one of the first to third passages in the second face plate has an opening at the inner circumferential wall of the second face plate. When the first piston and the second piston protrude in opposite directions from the first flange and the second flange, respectively, forces acting on the first piston and the second piston are canceled out via the main shaft.

[0018] In the case of a hollow main shaft, its interior space may be in communication with the central hole of the second face plate, thereby in communication with both the first face plate and the central hole of the second face plate.

[0019] The first faceplate and the second faceplate may be mechanically connected to one another through an auxiliary shaft extending through the interior space of the main shaft, thereby allowing the first faceplate and the second faceplate to rotate synchronously. The auxiliary shaft may be a hollow shaft that also allows hydraulic fluid to flow through the auxiliary shaft.

[0020] When the main shaft is provided with the first flange and the second flange, the main shaft may be rotatably mounted to the housing via a bearing between the first flange and the second flange.

[0021] The invention will be explained herein below with reference to highly schematic drawings which show, by way of example, embodiments of the invention. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a perspective view of an embodiment of a hydraulic transformer according to the present invention. [Figure 2] FIG. 2 is a view similar to FIG. 1 showing the hydraulic transformer from a different side. [Figure 3] FIG. 3 is an enlarged cutaway view of the hydraulic transformer shown in FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view of the hydraulic transformer shown in FIG. [Figure 5] FIG. 5 is a view similar to FIG. 4, but showing a part of it enlarged. [Figure 6] 6 is a perspective cross-sectional view from the opposite side of the first barrel member shown in FIG. 1. FIG. [Figure 7] 7 is a front elevational view of the second faceplate of the hydraulic transformer shown in FIG. 1. FIG. [Figure 8] FIG. 8 is a perspective view of the second faceplate shown in FIG. 7, showing its rear surface. [Figure 9] FIG. 9 is a perspective view of a portion of the housing of the hydraulic transformer shown in FIG. 1, illustrating two different operating states. [Figure 10] FIG. 10 is an illustration of hydraulic fluid flow through the high pressure channel of the hydraulic transformer shown in FIG. [Figure 11]FIG. 11 is a view similar to FIG. 10 illustrating the flow of hydraulic fluid through the low pressure channel of the hydraulic transformer shown in FIG. [Figure 12] FIG. 12 is a view similar to FIG. 10 illustrating the flow of hydraulic fluid through the working pressure channels of the hydraulic transformer shown in FIG. [Figure 13] FIG. 13 is a schematic diagram of a hydraulic circuit in and around the hydraulic transformer of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] 1 and 2 show the exterior of an embodiment of a hydraulic transformer 1 according to the present invention. The hydraulic transformer 1 comprises a housing 2, which comprises a high-pressure connection 3, a low-pressure connection 4, and two working pressure connections 5. The housing 2 forms an assembly of separate elements to accommodate the components within the housing 2. The hydraulic transformer 1 may be part of a hydraulic circuit comprising a high-pressure line communicating with the high-pressure connection 3 and a low-pressure line communicating with the low-pressure connection 4. The working pressure connection 5 may communicate with a hydraulic cylinder or hydraulic motor that can be driven by the hydraulic transformer 1 by adjusting the hydraulic pressure at the working pressure connection 5. The direction of hydraulic fluid flow from and to the working pressure connection 5 is controlled by valves, which will be described below with reference to FIG. 13.

[0024] 3 to 5 show the inside of the hydraulic transformer 1. The hydraulic transformer 1 has a hollow main shaft 6 supported by the housing 2 through a pair of angular contact roller bearings 7. The main shaft 6 is rotatable around a first rotation axis 8 relative to the housing 2. The bearing 7 is disposed in the center of the housing 2 in the longitudinal direction of the first rotation axis 8. The bearing 7 has a fixed position in the longitudinal direction of the first rotation axis 8 of the housing 2 by a collar 9 and a sleeve 10 of the housing 2, and the outer circumferential edge of the bearing 7 is sandwiched between the collar 9 and the sleeve 10 of the housing 2.

[0025] The main shaft 6 is provided with a first flange 11 and a second flange 12, which extend perpendicular to the first axis of rotation 8 on either side of the bearing 7. The inner circumferential edge of the bearing 7 is sandwiched between the first flange 11 and the second flange 12. The second flange 12 is attached to the main shaft 6 as a separate element after the bearing 7 is positioned next to the first flange 11. A key 13 locks the second flange 12 to the main shaft 6 in the direction of rotation around the first axis of rotation 8. The second flange 12 has a toothed circumference used for rotational speed detection (see FIG. 3).

[0026] A plurality of pistons 14 are fixed to each of the first flange 11 and the second flange 12 at equal angular intervals around the first axis of rotation 8, in this case fifteen pistons 14. The pistons 14 project away from each of the first flange 11 and second flange 12. The pistons 14 have centerlines extending parallel to the first axis of rotation 8. In this case, the pistons are fixed to each of the first flange 11 and second flange 12 by screws, although alternative fixing means are also contemplated.

[0027] Each of the pistons 14 cooperates with a respective sleeve 15 to form a compression chamber of variable volume. In this case, the hydraulic transformer 1 has 30 compression chambers. Each of the sleeves 15 has a sleeve bottom 16 with a central through-hole 17 and a circular-cylindrical sleeve jacket 18 (see FIG. 5 ). The sleeve jacket 18 extends from the sleeve bottom 16. Each piston 14 is sealed directly to the inner wall of the associated sleeve jacket 18 through its piston head, which has a spherical outer side.

[0028] The sleeve bottom 16 is supported by the bearing surfaces of the first barrel member 19 and the second barrel member 20. The sleeve 15 is slidable on the bearing surfaces of the first barrel member 19 and the second barrel member 20, which is known as the floating cup principle. The first barrel member 19 and the second barrel member 20 are mounted around the main shaft 6 by respective ball hinges 21 and connected to the main shaft 6 by a key 22 (see FIG. 5 ). Consequently, the first barrel member 19 and the second barrel member 20 rotate together with the main shaft 6 in an operating state. The first barrel member 19 and the second barrel member 20 are identical.

[0029] FIG. 6 shows the first barrel member 19 in more detail. The first barrel member 19 has a front surface 23 and a rear surface 24. The rear surface 24 faces the front surface 23 and the bearing surface. The front surface 23 faces toward the first flange 11, and the rear surface 24 faces away from the first flange 11. The first barrel member 19 is provided with an inner ring 25 and an outer ring 26 to hold the sleeve 15 in place during assembly. Each compression chamber communicates with a barrel port 27 on the rear surface 24 of the first barrel member 19 via a through-hole 17 in the sleeve bottom 16 and a barrel member passage. In this case, each of the barrel ports 27 has a pair of openings on the rear surface 24 of the first barrel member 19.

[0030] 3-5, the hydraulic transformer 1 includes a first faceplate 28 sandwiched between the housing 2 and the first barrel member 19 and a second faceplate 29 sandwiched between the housing 2 and the second barrel member 20. The first faceplate 28 and the second faceplate 29 are functionally identical but are mirror images of each other with respect to a plane perpendicular to the first rotation axis 8 and extending between the first faceplate 28 and the second faceplate 29. In the illustrated embodiment, the first faceplate 28 includes a front part 28a and a back part 28b that are fixed in position relative to each other. The first part 28a and the back part 28b may be made of different materials; however, alternatively, the first faceplate 28 may be a single member. Similarly, the second faceplate 29 includes a front part 29a and a back part 29b. Hereinafter, the first faceplate 28 and the second faceplate 29 will each be described as being a single piece.

[0031] Figure 7 shows the front side 30 of the second faceplate 29 facing the rear 24 of the second barrel member 20. Figure 8 shows the back side 31 of the second faceplate 29 facing the wall of the housing 2. The wall of the housing 2 supports the second faceplate 29, which in turn supports the second barrel member 20. Similarly, the opposite wall of the housing 2 supports the first faceplate 28, which in turn supports the first barrel member 20.

[0032] The housing 2 is configured such that the first face plate 28 and the second face plate 29 have an inclined orientation, thereby allowing the first barrel member 19 and the second barrel member 20 to rotate about second and third rotation axes 32 a, 32 b, respectively, such that the second and third rotation axes 32 a, 32 b are disposed at acute angles with respect to the first rotation axis 8. As a result, the first barrel member 19 and the second barrel member 20 rotate about their respective ball hinges 21 during rotation of the main shaft 6. The sleeve 15 rotates about their respective second and third rotation axes 32 a, 32 b. Consequently, the volume of the compression chamber changes in response to rotating the main shaft 6. The angles between the first rotation axis 8 and the second rotation axis 32a, and between the first rotation axis 8 and the third rotation axis 32b are in practice approximately 8 degrees, but may be smaller or larger.

[0033] The first barrel member 19 and the second barrel member 20 are respectively urged against the first face plate 28 and the second face plate 29 by springs 33 which are mounted in holes in the main shaft 6 and urge respective cheeks 34 against the first barrel member 19 and the second barrel member 20 (see FIG. 5).

[0034] During rotation of the first and second barrel members 19, 20, each sleeve 15 undergoes a combination of translational and orbital motion around the associated piston 14. Therefore, the exterior of each piston head is spherical. This spherical shape forms a seal line between the piston head and the sleeve jacket 18 that extends perpendicular to the centerline of the associated sleeve 15. The diameter of each piston 14 near the corresponding first or second flange 11, 12 is smaller than the diameter at the piston head to allow relative movement of the associated sleeve 15 around the piston 14. In operation, each piston 14 moves within the associated sleeve 15 between bottom and top dead centers. In the drawing of FIG. 5, the upper pistons 14 in the first barrel member 19 and the second barrel member 20 are at top dead center, and the lower pistons 14 in the first barrel member 19 and the second barrel member 20 are at bottom dead center.

[0035] 7 and 8, the second faceplate 29 is provided with a high-pressure passage 35, a low-pressure passage 36, and an actuation pressure passage 37. The high-pressure passage 35 has eight through-holes and forms a high-pressure port at its front surface 30 and a high-pressure port at its rear surface 31. Each high-pressure port is partially circular and extends within an angle of approximately 160 degrees about the third axis of rotation 32b, although different arc lengths are contemplated. The low-pressure passage 36 has four through-holes and forms a low-pressure port at its front surface 30 and a low-pressure port at its rear surface 31. The low-pressure port is partially circular and has a length shorter than the high-pressure port at either the front surface 30 or the rear surface 31, as measured in the direction of rotation about the third axis of rotation 32b. The actuation pressure passage 37 has three through-holes and forms an actuation pressure port at its front surface 30 and a high-pressure port at its rear surface 31. The actuation pressure port is partially circular and has a length on both the front surface 30 and the rear surface 31 that is shorter than the length of the low pressure port when measured in a rotational direction about the third axis of rotation 32b.

[0036] In response to rotating the main shaft 6, the barrel ports 27 of the second barrel member 20 move along the high pressure port, the low pressure port, and the operating pressure port on the front surface 30 of the second faceplate 29. Similarly, in response to rotating the main shaft 6, the barrel ports 27 of the first barrel member 19 move along the high pressure port, the low pressure port, and the operating pressure port on the front surface 30 of the first faceplate 28.

[0037] The high pressure passages 35 of the first faceplate 28 and the second faceplate 29 communicate with the high pressure connection 3 of the housing 2, the low pressure passages 36 of the first faceplate 28 and the second faceplate 29 communicate with the low pressure connection 4 of the housing 2, and the operating pressure passages 37 of the first faceplate 28 and the second faceplate 29 communicate with the two operating pressure connections 5 of the housing 2.

[0038] The first faceplate 28 and the second faceplate 29 are rotatable by a predetermined angle α (e.g., 70 degrees) around the second rotation axis 32a and the third rotation axis 32b, respectively, relative to the housing 2. In the illustrated embodiment, the second faceplate 29 is rotatable by a servo actuator 38, while the first faceplate 28 is rotatable synchronously with the second faceplate 29 by a hollow auxiliary shaft 39 connecting the first faceplate 28 and the second faceplate 29 to each other via a pin 40 (see FIGS. 3 to 5).

[0039] Figure 9 shows the inner wall of the housing 2 that supports the rear surface 31 of the second faceplate 29. The inner wall is provided with a partially circular high-pressure port 41 that communicates with the high-pressure connection 3 of the housing 2. Figure 9 illustrates two extreme rotational positions of the second faceplate 29 when rotated about the third rotation axis 32b relative to the housing 2, using projections A of the high-pressure port of the high-pressure passage 35 on the rear surface 31 of the second faceplate 29, projections T of the low-pressure port of the low-pressure passage 37 on the rear surface 31 of the second faceplate 29, and projections B of the working pressure port of the working pressure passage 37 on the rear surface 31 of the second faceplate 29. Between the extreme positions, the high-pressure port 41 of the housing 2 communicates with the high-pressure port on the rear surface 31 of the second faceplate 29. It can be seen that the arc length of the high-pressure port 41 in the housing 2 is shorter than the arc length of the high-pressure port at the rear surface 31 of the second faceplate 29. This means that a portion of the high-pressure port at the rear surface 31 of the second faceplate 29 is always closed by the wall of the housing 2. To ensure sufficient flow area between the second barrel member 20 and the high-pressure port 41 in the housing 2, the second faceplate 29 may be provided with channels 42 between non-adjacent high-pressure passages 35 (see FIG. 7 ). The channels 42 are drilled from the outside in the circumferential direction of the second faceplate 29, while inserts 43 seal each channel 42. The first faceplate 28 and the wall of the housing 2 supporting the first faceplate 28 are similar to the second faceplate 29 and the wall of the housing 2 supporting the second faceplate 29.

[0040] The housing 2 is provided with a high pressure channel 44 through which high pressure ports at the rear surface 31 of each of the first and second faceplates 28, 29 communicate with the high pressure connection 3 of the housing 2. This is shown in Figure 10, which illustrates by dashed lines and arrows that hydraulic fluid can flow in the reverse direction through high pressure channel 44.

[0041] 7 and 8, the low-pressure channel 36 is formed by through-holes between the front surface 30 and the rear surface 31 of the second faceplate 29 and radial channels 45 drilled from the circumferential outside of the second faceplate 29 to the respective through-holes. In the assembled state, as shown in FIG. 9 by projection T, the through-holes are closed by the wall of the housing 2 at the rear surface 31 of the second faceplate 29. This causes the low-pressure channel 36 to form a 90-degree bend between the first faceplate 28 and the second faceplate 29. The low-pressure channel 36 communicates with the low-pressure connection 4 through a low-pressure channel 46 formed by the internal space of the housing 2. FIG. 11 shows, with dashed lines and arrows, the flow pattern of hydraulic fluid through the low-pressure channel 46, indicating that the hydraulic fluid can flow in the reverse direction.

[0042] 7 and 8 , the actuation pressure channel 37 is formed by through holes between the front surface 30 and the back surface 31 of the second faceplate 29 and radial holes 48 drilled through each through hole from the circumferential outer side of the second faceplate 29 to a central hole 49 of the second faceplate 29. The central hole 49 is a through hole. An insert 50 seals each radial hole 48 at the periphery of the second faceplate 29. In the assembled state, the through holes of the actuation pressure channel 37 are closed at the back surface 31 of the second faceplate 29 by the wall of the housing 2, as shown in FIG. 9 by projection B. This causes the actuation pressure channel 37 to form a 90-degree bend in the first faceplate 28 and the second faceplate 29.

[0043] The actuation pressure channel 37 communicates with the actuation pressure connection 5 through an actuation pressure channel 51, which is formed by the central bore 49 of the first and second face plates 28 and 29, the central bores of the first and second barrel members 19 and 20, and the interior space of the main shaft 6 (see FIG. 12). The actuation pressure channel 51 is sealed from the low-pressure channel 46, i.e., the interior space of the housing 2, by the inner sleeve 52 and cooperating outer sleeve 53 (see FIG. 5). The outer sleeve 53 is attached to the first and second barrel members 19 and 20, respectively. The outer sleeve 53 is slidable relative to the first and second barrel members 19 and 20 along the second rotation axis 32a and the third opening axis 32b. Each of the inner sleeves 52 is fixed to the main shaft 6 and has a spherical outer surface portion that contacts the inner cylindrical wall of the associated outer sleeve 53. The spherical outer surface portion may have a center point that coincides with the center point of the respective ball hinge 21. Figure 12 shows, by dashed lines and arrows, the flow pattern of hydraulic fluid through the actuation pressure passage 37 and the actuation pressure channel 51. Although not shown in Figure 12, the hydraulic fluid can also flow in the opposite direction.

[0044] 7 and 8, the high-pressure port at the front surface 30 of the second faceplate 29 and the high-pressure port at the back surface 31 of the second faceplate 29 are aligned and have substantially the same shape and size. Similarly, the low-pressure port at the front surface 30 of the second faceplate 29 and the low-pressure port at the back surface 31 of the second faceplate 29 are aligned and have substantially the same shape and size. Similarly, the actuation pressure port at the front surface 30 of the second faceplate 29 and the actuation pressure port at the back surface 31 of the second faceplate 29 are aligned and have substantially the same shape and size.

[0045] 7 shows that when the second faceplate 29 is viewed angularly about the third axis of rotation 32b, a series of small through-holes 54 are provided in the sealing lands between the high-pressure port and the low-pressure port, between the low-pressure port and the operating pressure port, and between the high-pressure port and the operating pressure port. The flow-through area of ​​each through-hole 54 at the front surface 30 of the second faceplate 29 is less than 5% of the flow-through area of ​​the first passageway 35 and is also smaller than the flow-through area of ​​each of the barrel ports 27 of the second barrel member 20 that move along the through-hole 54.

[0046] 8 shows that the through-holes 54 form pockets 55 at the rear surface 31 of the second faceplate 29, each having a larger cross-sectional area than the through-holes 54 at the front surface 30 of the second faceplate 29. In operation, the barrel ports 27 of the second barrel member 20 move along the through-holes 54, thus generating pressure fields at the front surface 30 of the second faceplate 29 between the high-pressure port and the low-pressure port, between the low-pressure port and the operating pressure port, and between the high-pressure port and the operating pressure port. Due to the presence of the through-holes 54 and the pockets 55, counter-balancing pressure fields are generated at the rear surface 31 of the second faceplate 29. This minimizes friction between the second faceplate 29 and the housing 2, thereby facilitating adjustment of the rotational position of the second faceplate 29 relative to the housing 2. Note that the first faceplate 28 is also provided with the through-hole 54 and the pocket 55 .

[0047] As previously described herein, the second faceplate 29 is rotatable by a servo actuator 38, which must overcome the torque loads of the first and second faceplates 28 and 29. Referring to FIG. 4 , the servo actuator 38 is connected to an electric servo motor 56, which in turn controls a control shaft 57 having ports communicating with the low-pressure channel 46 and the high-pressure channel 44, respectively. The hydraulic servo actuator 38 has a rotor and a stator, each with three ribs that form six displacement chambers. The pressure within these chambers is controlled by the rotational position of the control shaft 57. The actual rotational position of the second faceplate 29 relative to the housing 2 is determined by a position sensor 58.

[0048] The rotation angles of the first and second faceplates 28, 29 are defined by respective arcuate grooves 59 in their rear surfaces 31 (see FIGS. 5 and 8), into which pins 60 fit (see FIG. 4). The pins 60 may be bolts that are threaded into the housing 2.

[0049] Figure 13 illustrates the hydraulic circuit in and around the hydraulic transformer 1. The working pressure connection 5 is connected to a hydraulic cylinder that can be extended or retracted through a control valve 61, which is also shown in Figures 1-4 and 10-11. The high pressure connection 3 communicates with a high pressure line HP, and the low pressure connection 4 communicates with a low pressure line LP. The hydraulic transformer 1 also has two check valves 62 to avoid cavitation, which are also shown in Figures 1 and 11.

[0050] Figures 11 and 13 show that the low-pressure channel 46 is fluidly connected to a check valve 62 and a control valve 61. Figure 13 shows that the actuation pressure channel 51 is fluidly connected to the control valve 61. The control valve 61 can be operated to allow hydraulic fluid to flow from the actuation pressure channel 51 to the underside of the hydraulic cylinder and from the top of the hydraulic cylinder to the low-pressure channel 46 to extend the hydraulic cylinder. Similarly, the control valve 61 can be operated to allow hydraulic fluid to flow from the bottom of the hydraulic cylinder to the actuation pressure channel 51 and from the low-pressure channel 46 to the top of the hydraulic cylinder to retract the hydraulic cylinder.

[0051] For example, if an external load acts on the hydraulic cylinder while it is retracting, the load may force hydraulic fluid to flow through the actuation pressure channel 51, resulting in compressed hydraulic fluid being transported to the high-pressure line HP via the high-pressure channel 44 and the high-pressure connection 3. This means that the energy for retracting the cylinder due to the external load is recovered and converted into hydraulic pressure in the high-pressure line HP. It should be noted that the high-pressure line HP and also the low-pressure line LP may be provided with a pressure accumulator.

[0052] The invention is not limited to the embodiments shown in the drawings and described above, which may be modified in various ways within the scope of the claims and their technical equivalents.

Claims

1. A hydraulic transformer (1) comprising: a housing (2) having a high-pressure connection (3), a low-pressure connection (4), and an operating pressure connection (5); and a barrel member (19, 20) rotatably mounted within the housing (2), the barrel member (19, 20) having a plurality of compression chambers whose volumes change in response to rotation of the barrel member (19, 20), wherein a rear surface (24) of the barrel member (19, 20) has a plurality of barrel ports (27) communicating with each of the compression chambers; The faceplates (28, 29) are supported by the housing (2), and each faceplate (28, 29) has a front surface (30) that supports the rear surface (24) of the barrel member (19, 20), a rear surface (31) that faces the housing (2), a circumferential outer wall, and a central hole (49) that is surrounded by a circumferential inner wall, and the faceplates (28, 29) are rotatable within a predetermined angle relative to the housing (2), and the front surface (30) has three arc-shaped faceplate ports. In response to the rotation of the barrel members (19, 20), the plurality of barrel ports (27) move along the three arc-shaped faceplate ports, and the three arc-shaped faceplate ports are respectively connected to the high pressure connection (3) through a first passage (35) in the faceplates (28, 29), the low pressure connection (4) through a second passage (36) in the faceplates (28, 29), and the working pressure connection ( 5), wherein one of the first to third passages (35, 36, 37) has an opening at the back surface (31) of the face plates (28, 29), one of the first to third passages (35, 36, 37) has an opening at the outer circumferential wall of the face plates (28, 29), and one of the first to third passages (35, 36, 37) has an opening at the inner circumferential wall of the face plates (28, 29).

2. The hydraulic transformer (1) comprises a main shaft (6) through which the barrel members (19, 20) are rotatable relative to the housing (2), the main shaft (6) is mounted within the housing (2) and is rotatable about a first rotation axis (8), the main shaft (6) has flanges (11, 12) extending perpendicular to the first rotation axis (8), and a plurality of pistons (14) each having an individual spherical piston head, the plurality of pistons (14) being fixed to the flanges (11, 12) at equal angular intervals around the first rotation axis (8) and having a centerline parallel to the first rotation axis (8), the barrel members (19, 20) having a plurality of independent sleeves (15) within which the individual pistons (14) are movable, and thus 2. The hydraulic transformer (1) according to claim 1, wherein the compression chambers are formed, and wherein a bearing surface of the barrel members (19, 20) opposite to a back surface (24) of the barrel members (19, 20) supports a sleeve bottom (16) of the sleeve (15), and wherein the barrel members (19, 20) equipped with the sleeve (15) are rotatable about a second rotation axis (32a, 32b) intersecting the first rotation axis (8) at an acute angle such that each of the pistons (14) moves between bottom dead center and top dead center relative to the associated sleeve (15) in response to rotation of the main shaft (6) and the barrel members (19, 20) equipped with the sleeve (15), and wherein the barrel ports (27) communicate with each of the compression chambers through barrel member passages in the barrel members (19, 20) and through holes (17) in the sleeve bottom (16).

3. 3. A hydraulic transformer (1) according to claim 1 or 2, wherein the central hole (49) in the face plates (28, 29) is a through hole.

4. 4. The hydraulic transformer (1) according to claim 1, wherein the first passage (35) has an opening at the back surface of the face plates (28, 29), the second passage (36) has an opening at the outer circumferential wall of the face plates (28, 29), and the third passage (37) has an opening at the inner circumferential wall of the face plates (28, 29).

5. 5. The hydraulic transformer (1) according to claim 1, wherein the openings in the rear surfaces (31) of the faceplates (28, 29) are aligned with the associated faceplate ports and preferably have substantially the same shape and dimensions as the associated faceplate ports.

6. 6. The hydraulic transformer (1) according to claim 1, wherein one of the first to third passages (35, 36, 37) having an opening in the circumferential outer wall of the faceplate (28, 29) also has an opening in the rear surface (31) of the faceplate (28, 29) that is aligned with the associated faceplate port and is closed by an inner wall of the housing (2), and preferably has substantially the same shape and dimensions as the associated faceplate port.

7. 7. The hydraulic transformer (1) according to claim 1, wherein one of the first to third passages (35, 36, 37) having an opening in the inner wall of the faceplate (28, 29) also has an opening in the back surface (31) of the faceplate (28, 29) that is aligned with the associated faceplate port and is closed by the inner wall of the housing (2), and preferably has substantially the same shape and dimensions as the associated faceplate port.

8. The hydraulic transformer (1) according to any one of claims 1 to 7 and claim 2, wherein the main shaft (6) is a hollow main shaft, and an internal space of the hollow main shaft is in communication with the central hole (49) of the face plates (28, 29) through a central hole in the barrel members (19, 20), and preferably, one of the central hole of the barrel members (19, 20) and the main shaft (6) is provided with an inner sleeve (52) having a spherical outer surface portion, and the other of the central hole of the barrel members (19, 20) and the main shaft (6) is provided with an outer sleeve (53) having a cylindrical inner surface that fits around the spherical outer surface portion of the inner sleeve (52).

9. 9. The hydraulic transformer (1) according to claim 1, wherein the arc length of the faceplate port communicating with the high pressure connection (3) is greater than the arc length of the faceplate port communicating with the low pressure connection (4) and is also greater than the arc length of the faceplate port communicating with the working pressure connection (5).

10. 10. The hydraulic transformer (1) according to claim 9, wherein the arc length of the faceplate port communicating with the working pressure connection (5) is smaller than the arc length of the faceplate port communicating with the low pressure connection (4).

11. 11. The hydraulic transformer (1) according to claim 1, wherein, in a rotational direction around the second rotation axis (32a, 32b), the faceplate ports are separated by individual seal lands, and wherein at least one of the seal lands is provided with a through hole (54) between the front surface (30) and the rear surface (31) of the faceplate (28, 29), the through hole having a flow-through area that is less than 5% of the flow-through area of ​​the first passage (35) and extending from the front surface toward the rear surface of the faceplate.

12. 12. The hydraulic transformer (1) according to claim 11, wherein the flow-through area at the rear surface (31) of the faceplate (28, 29) is formed by a pocket.

13. The flange with the piston is a first flange (11) with a first piston (14), and the main shaft (6) is provided with a second flange (12) extending perpendicular to the first rotation axis (8), wherein the hydraulic transformer (1) is provided with a plurality of second pistons (14) with individual spherical piston heads, the plurality of second pistons (14) are fixed to the second flange (12) at equal angular intervals around the first rotation axis (8) and have centerlines parallel to the first rotation axis (8), wherein the barrel member with the sleeve is a first barrel member (19) with a first sleeve, and the plurality of compression chambers are a plurality of first compression chambers, wherein the hydraulic transformer The hydraulic transformer (1) is provided with a plurality of independent second sleeves (15) within which the individual second pistons (14) are movable, wherein the hydraulic transformer (1) is provided with a second barrel member (20) that is rotatable relative to the housing (2) and a plurality of independent second sleeves (15) within which the individual second pistons (14) are movable, thus forming individual second compression chambers, wherein a bearing surface of the second barrel member (20) opposite to a back surface (24) of the second barrel member (20) supports a sleeve bottom (16) of the second sleeve (15), wherein the main shaft (6) and the second sleeve (15) are connected to each other. The second barrel member (20) including the second sleeve (15) is rotatable about a third rotation axis (32b) intersecting the first rotation axis (8) at an acute angle, such that each of the second pistons (14) moves between bottom dead center and top dead center relative to the associated second sleeve (15) in response to rotation of the second barrel member (20) including the second sleeve (15), wherein the back surface (24) of the second barrel member (20) includes second barrel ports (27) communicating with the respective second compression chambers through barrel member passages in the second barrel member (20) and through holes (17) in the sleeve bottom (16) of the second sleeve (15), wherein:The face plate is a first face plate (28), and the hydraulic transformer (1) is provided with a second face plate (29) supported by the housing (2), and the front face (30) supports the back face (24) of the second barrel member (20), a back face (31) facing the housing (2), a circumferential outer wall, and a central hole (49) surrounded by a circumferential inner wall, and the second face plate (29) is provided with the third circumferential wall (49) and the front face (30) supports the back face (24) of the second barrel member (20), a back face (31) facing the housing (2), a circumferential outer wall, and a central hole (49) surrounded by a circumferential inner wall, and the second face plate (29) is provided with the third circumferential wall (49) and the second circumferential wall (49) and the second circumferential wall (49) are ... The faceplate port is rotatable within a predetermined angle around a rotation axis (32b), wherein the faceplate port is a first faceplate port, and the front surface (30) of the second faceplate is provided with three arc-shaped second faceplate ports, and the second barrel port (27) moves along the three arc-shaped second faceplate ports in response to the rotation of the main shaft (6) and the second barrel member (20) including the second sleeve (15), wherein The second faceplate port communicates with the high pressure connection (3) through a first passage in the second faceplate (29), with the low pressure connection (4) through a second passage in the second faceplate (29), and with the working pressure connection (5) through a third passage in the second faceplate (29), respectively, wherein one of the first passage to the third passage (35, 36, 37) in the second faceplate (29) is connected to the second faceplate (29).

13. The hydraulic transformer (1) according to claim 1 or 2, wherein one of the first to third passages (35, 36, 37) in the second face plate (29) has an opening at the back surface (31) of the second face plate (29), one of the first to third passages (35, 36, 37) in the second face plate (29) has an opening at the outer wall of the second face plate (29) in the circumferential direction, and one of the first to third passages (35, 36, 37) in the second face plate (29) has an opening at the inner wall of the second face plate (29) in the circumferential direction.

14. The hydraulic transformer (1) according to any one of claims 8 to 13, wherein the internal space of the main shaft (6) communicates with the central hole (49) of the second face plate (29).

15. 15. The hydraulic transformer (1) according to claim 14, wherein the first face plate and the second face plate (28, 29) are mechanically connected to each other through an auxiliary shaft (39) extending through the internal space of the main shaft (6), and wherein preferably the auxiliary shaft (39) is a hollow shaft.

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