Integrated electro-hydraulic unit

Abstract

An integrated electro-hydraulic unit comprises a hydraulic machine having a shaft configured to rotate about an axis and a cylinder block. The cylinder block includes a distal section spaced from the axis. The distal section has an axial extension measured parallel to the axis. An electric machine has a stator and a rotor with an axial extension measured parallel to the axis. The axial extension of the rotor is greater than the axial extension of the distal section. A drive flange is located between the distal section and the rotor to define an interface. The rotor is secured to a rotor receiving section of the drive flange. The axial extension of the distal section is greater than the axial extension of the rotor.

Description

Field of invention

[0001] The present disclosure relates to an electric and hydraulic machine. In particular, the present disclosure relates to an integrated electro-hydraulic unit. Background of the invention

[0002] Electrically driven hydraulic pumps, commonly referred to as e-pumps, have spurred the development of effective cooling solutions for electric machines. Traditionally, electric machines are cooled using a fluid separate from the hydraulic pump's working fluid. In some cases, the electric machine is integrated with the hydraulic machine, known as an integrated electro-hydraulic unit, as a single design to improve power-to-weight ratio. However, conventional methods for cooling an electric machine become more challenging when configuring an integrated electro-hydraulic unit. Therefore, it may be more desirable to utilize the hydraulic machine's working fluid for cooling purposes.

[0003] In the prior art, cooling solutions can be divided into the following categories: solutions that use the working fluid after it has been pressurized by the pump, solutions that use the return flow of the working fluid, and solutions that use internal leakage flow.

[0004] While the cooling function is achieved, each solution has drawbacks. Solutions that utilize the working fluid after it has been pressurized by the pump affect the volumetric efficiency of the hydraulic machine. Volumetric efficiency is the ratio of the actual flow rate to the theoretical outlet flow rate. The volumetric efficiency decreases because a portion of the flow is used for cooling. Solutions that utilize the return flow impose constraints on the circuit design and the construction of the hydraulic machine (for example, in some hydraulic circuits, the return flow is not related to the flow of the hydraulic machine). Solutions that utilize internal leakage flow provide insufficient flow for proper cooling of the electrical machine and are more susceptible to contamination. Brief description of the invention

[0005] The present invention provides, in one aspect, an integrated electro-hydraulic unit comprising a hydraulic machine with a shaft and a cylinder block coupled to the shaft. The shaft is configured to rotate about a central axis. The cylinder block comprises a plurality of pistons within the cylinder block. The cylinder block is configured to rotate about the central axis to generate a stroke motion for each of the plurality of pistons. The cylinder block comprises a distal section spaced from the central axis. The distal section has an axial extension measured parallel to the central axis between a first and a second axial end of the distal section. The integrated electro-hydraulic unit comprises an electric machine comprising a stator and a rotor comprising a plurality of rotor plates.The rotor has an axial extension measured parallel to the central axis between the first and a second axial end of the rotor. The axial extension of the rotor is greater than the axial extension of the distal portion of the cylinder block. The integrated electro-hydraulic unit includes a drive flange located radially outside the cylinder block and radially inside the rotor to define an interface between the distal portion of the cylinder block and the rotor. The majority of stacked plates are secured to a rotor-receiving outer portion of the drive flange, and the distal portion of the cylinder block is secured to a cylinder-block-receiving inner portion of the drive flange. The axial extension of the distal portion of the cylinder block is greater than the axial extension of the rotor.

[0006] In a further aspect, the present invention provides an integrated electro-hydraulic unit comprising a hydraulic machine with a shaft and a cylinder block coupled to the shaft. The shaft is configured to rotate about a central axis. The cylinder block comprises a plurality of pistons within the cylinder block. The cylinder block is configured to rotate about the central axis to generate a stroke motion for each of the plurality of pistons. The cylinder block comprises a distal section spaced from the central axis. The distal section has an axial extension measured parallel to the central axis between a first and a second axial end of the distal section. The integrated electro-hydraulic unit comprises an electric machine comprising a stator and a rotor comprising a plurality of rotor plates.The rotor has an axial extension measured parallel to the central axis between the first and a second axial end of the rotor. The integrated electro-hydraulic unit includes a drive flange located radially outside the cylinder block and radially inside the rotor to define an interface between the cylinder block and the rotor. The majority of stacked plates are secured to a rotor-receiving outer section of the drive flange, and the distal section of the cylinder block is secured to a cylinder-block-receiving inner section of the drive flange. The first end of the distal section of the cylinder block lies axially inside the axial extension of the rotor, and the second end of the distal section of the cylinder block lies axially outside the axial extension of the rotor, such that only a portion of the axial extension of the distal section of the cylinder block overlaps the axial extension of the rotor. Brief description of the drawings Fig. Figure 1 is a perspective view of an integrated electro-hydraulic unit. Fig. 2 is a longitudinal cross-section of the integrated electro-hydraulic unit along line 2-2 of Fig. 1. Fig. Figure 3 is a longitudinal cross-section of the integrated electro-hydraulic unit along line 3-3 of Fig. 1. Fig. Figure 4 is a perspective view of the integrated electro-hydraulic unit of Fig. 1, wherein a terminal end housing is removed and separated from a common enclosure. Fig. Figure 5 is an end view of an embodiment of a valve plate of the integrated electro-hydraulic unit, which includes a third channel. Fig. Figure 6 is an end view of an embodiment of the valve plate of the integrated electro-hydraulic unit, which includes a fourth channel. Fig. Figure 7 is an end view of an embodiment of the valve plate of the integrated electro-hydraulic unit, which includes an offset third channel. Fig. Figure 8A is an end view of an embodiment of the valve plate of the integrated electro-hydraulic unit, which includes the offset third channel. Fig. Figure 8B is an end view of an embodiment of the valve plate of the integrated electro-hydraulic unit, which includes the offset third channel and an offset fourth channel. Fig. Figure 9A is a perspective view of an embodiment of a plate for use with the valve plate of Fig. 8A or Fig. 8B. Fig. Figure 9B is a perspective view of an embodiment of a plate for use with the valve plate of Fig. 8A or Fig. 8B. Fig. Figure 10 is a perspective sectional view of the integrated electro-hydraulic unit of Fig. 2, in which a first and a second direction of rotation are specified. Fig. Figure 11 is a longitudinal cross-section of an alternative embodiment of the integrated electro-hydraulic unit along line 3-3 of Fig. Figure 1 shows additional electrical components and additional associated hydraulic units. Fig. Figure 12 is a diagram of the piston speed with a first rotational position line. Fig. Figure 13 is a schematic detailed end view of an embodiment of the valve plate, which includes the third channel and the fourth channel with check valves. Fig. Figure 14 is a perspective view of the connection end housing for the integrated electro-hydraulic unit. Fig. Figure 15 is a perspective view of an embodiment of an integrated electro-hydraulic unit. Fig. Figure 16 is a longitudinal cross-section of the integrated electro-hydraulic unit along line 16-16 of Fig. Figure 15, which shows an embodiment of an electric machine, a drive flange and a cylinder block. Fig. Figure 17 is a perspective view of the drive flange of Fig. 16. Fig. 18 is a longitudinal cross-section of the drive flange along line 18-18 of Fig. 17. Detailed description

[0007] Fig. Figures 1-4 represent an integrated electro-hydraulic unit 10 according to a design described in the present disclosure. The integrated electro-hydraulic unit 10 comprises an electric machine 14, a hydraulic machine 18, and an enclosure 22 as shown in the illustration. Fig. 2. The enclosure 22 comprises a radial enclosure 26, a swashplate end housing 30, and a terminal end housing 34. Fasteners 38 extend transversely to the end housings 30 and 34 and parallel to a common axis of rotation A1 of the electric motor 14 and the hydraulic motor 18. The fasteners 38 secure the swashplate end housing 30 and the terminal end housing 34 to one another with the radial enclosure 26 between them. Thus, the enclosure 22 forms a single divided internal cavity for the electric motor 14 and the hydraulic motor 18, as discussed in more detail below. The enclosure 22 is attached to the swashplate end housing 30 and the terminal end housing 34 by fasteners 42 using fasteners 46. The swashplate end housing 30 includes a recess 50 for an electrical connection and, in some embodiments, an outlet channel 54.In further embodiments, the outlet channel 54 is contained in the radial covering 26, as in . Fig. Figure 11 shows that the recess 50 for an electrical connection accommodates the cables 58 leading to the electric machine 14. The cables 58 are used to supply current to the electric machine 14. The terminal housing 34 includes a first opening 59 and a second opening 60, as shown in Figure 11. Fig. 3 is shown.

[0008] The integrated electro-hydraulic unit 10 integrates the electric machine 14 and the hydraulic machine 18 so that they can alternately convert mechanical force into hydraulic force, a process known as pumping. The electric machine 14 can be a motor with any suitable topology, including, but not limited to, induction, surface permanent magnet, internal permanent magnet, wound rotor, and switched reluctance. The hydraulic machine 18 can be an axial piston machine with a swashplate (as shown) or a swashplate pump based on the same principles but without a moving swashplate. The enclosure 22 is a common enclosure that surrounds the electric machine 14 and the hydraulic machine 18 together. As shown in Fig. As shown in Figure 2, the hydraulic machine 18 is nested inside the electric machine 14, such that the electric machine 14 surrounds the hydraulic machine 18. In the enclosure 22, there is a gap 158 between the terminal end housing 34 and next to the end of the electric machine 14, as shown in Figure 2. Fig. Figure 4 shows that a cooling pipe 118 is provided in the intermediate space 158. A cooling flow 62 of the working fluid processed by the hydraulic machine 18 exits from the cooling pipe 118 into the intermediate space 158. The cooling flow 62 enters a cooling passage 159, defined between the electric machine 14 and the hydraulic machine 18, and flows to an intermediate space 160 between the swashplate end housing and adjacent to the front of the electric machine 14, as shown in Figure 4. Fig. Figure 3 shows that the enclosure 22 fluidically seals the electric machine 14 and the hydraulic machine 18. In one embodiment, the first opening 59, the second opening 60, and the outlet channel 54 are the only points where the working fluid can enter and exit the enclosure 22.

[0009] Other configurations of the integrated electro-hydraulic unit 10 may include an additional integrated electro-hydraulic unit 20 with a separate enclosure from the integrated electro-hydraulic unit 10 and use a connector 24 to direct a cooling flow 62 to the additional integrated electro-hydraulic unit 20, as shown in Fig. Figure 11 shows that in further embodiments, several electro-hydraulic units can be stacked on a common shaft or in the same enclosure 22. The stacked electro-hydraulic units operate with a single inverter, thereby reducing the cooling requirements in stacked electro-hydraulic unit architectures.

[0010] As in Fig. As shown in Figure 2, the electric machine 14 comprises a rotor 66 and a stator 70 with one winding. The stator 70 is positioned closest to the radial outer casing 26 of the common casing 22. The rotor 66 is positioned radially inward from the stator 70 toward the axis A1. Both the rotor 66 and the stator 70 surround the hydraulic machine 18. As shown in Fig. As shown in Figure 2, the electric machine 14 and the hydraulic machine 18 are configured for immersion cooling with the cooling flow 62. In immersion cooling, the space between 158 and 160 within the enclosure 22, which houses the electric machine 14 and the hydraulic machine 18, is essentially filled with the working fluid, which continuously moves through the integrated electro-hydraulic unit 10 to form the cooling flow 62.

[0011] In certain embodiments as shown in Fig. 3. The hydraulic machine 18 can be an axial piston machine with a swashplate. The hydraulic machine 18 comprises a rotating working assembly 86 for working on the working fluid. The rotating assembly 86 comprises a cylinder block 74, a shaft 78, a drive flange 82, a swashplate 90, a plurality of pistons 94, a plurality of sliding blocks 98, a retaining plate 102, and a valve plate 92. The cylinder block 74 is rotatably supported by the shaft 78 about the axis A1 on bearings 80. The cylinder block 74 is rotatable about the axis A1 in a first direction of rotation R1. The cylinder block 74 has a first end 106 near the swashplate end housing 30 and a second end 146 near the connection end housing 34. The cylinder block 74 includes a cylinder block end 190 at the second end 146, as shown in Fig. Figure 4 shows that the cylinder block end 190 comprises a plurality of slots 192 positioned around the circumference of the axis A1. The drive flange 82 is positioned between the cylinder block 74 and the rotor 66 and rotatably couples the cylinder block 74 to the rotor 66. The swashplate 90 is positioned along the axis A1 and is in contact with the plurality of sliding pieces 98 towards the first end 106 of the cylinder block 74. The plurality of pistons 94 are received radially around the axis A1 in the cylinder block 74. The valve plate 92 is positioned along the axis A1 and between the cylinder block end 190 of the cylinder block 74 and the terminal end housing 34, as best shown in Figure 4. Fig. Figure 4 shows that the terminal end housing 34 has a projection 110 extending to the second end 146 of the cylinder block 74. The projection 110 contacts the valve plate 92 and includes the first opening 59, the second opening 60, and a third passage 114, all of which are connected to the valve plate 92, as shown in Figure 4. Fig. 3 and Fig. 16 is shown.

[0012] The terminal end housing 34 includes the cooling tube 118, which surrounds the axis A1. The cooling tube 118 can have any suitable geometry, including, but not limited to, linear segments, arc-shaped segments, or as shown in the figure. Fig. 14 The cooling tube 118 can have seven linear segments forming a heptagonal shape. The cooling tube 118 is connected to the projection 110 of the terminal end housing 34 by a connector 119, as shown in Fig. Figure 4 shows that in the illustrated embodiment, the connector 119 is a "T" connector. The cooling tube 118 comprises a wall or surface 154 with a plurality of recesses 150. The recesses 150 are distributed along the length of the cooling tube 118 (e.g., uniformly). As shown in Fig. As shown in Figure 14, the cooling tube 118 can have ten or more recesses 150 (e.g., twenty of the recesses 150). In some cases, the cooling tube 118 is secured to the terminal end housing 34 at one or more points (e.g., with a bracket or holder 122 and a fastening element 126, as shown in Figure 14). Fig. 14) and is in flow communication with the third passage 114 through the connecting piece 119, as shown in Fig. Figure 2 shows that the recesses 150 can be evenly distributed along the length of the cooling tube 118. The cooling tube 118 directs the cooling flow 62 into the space 158 through the majority of the recesses 150.

[0013] In some embodiments, the valve plate 92 comprises a first channel 130, a second channel 134 and a third channel 138, as shown in Fig. Figure 5 is shown. The second channel 134 has a reduced cross-sectional area compared to the first channel 130 in order to accommodate the third channel 138.

[0014] The center of the third channel 138 is located within a first angular span Φ at the valve plate 92, passing a first rotational position line 142. The first rotational position line 142 corresponds to a bottom dead center, as shown in Fig. 5 and Fig. Figure 12 shows that the first angular span Φ is 25 degrees in some cases. By strategically positioning the third channel 138 on the valve plate 92, the speed of the majority of pistons 94 at this point is comparatively low compared to the maximum speed of the majority of pistons 94, as shown in Figure 12. Fig. Figure 12 illustrates this. The flow rate of the working fluid displaced by the plurality of pistons 94 is directly related to the velocity of the plurality of pistons 94. The low velocity of the plurality of pistons 94 within the first angular span Φ corresponds to a low flow rate of the working fluid used for the cooling flow 62. The low flow rate of the working fluid is desirable for the cooling flow 62 because it results in less disturbance of the overall fluid flow in the integrated electrohydraulic unit 10. As shown in Fig. As shown in Figure 5, the third channel 138 is positioned near bottom dead center (BDC), which corresponds to a region with a relatively low piston speed and thus a low flow rate of the working fluid used for the cooling flow 62. The valve plate 92 is connected to the cylinder block end 190 as shown in Figure 5. Fig. 4 used. The cylinder block end 190 comprises the plurality of slots 192 according to the above description, all slots having an identical shape.

[0015] The cylinder block 74 is configured to rotate clockwise around the axis A1 in the first direction of rotation R1, as shown in Fig. Figure 10 shows that during the movement in the first direction of rotation R1 of the cylinder block 74, each of the plurality of pistons 94 moves in a stroke from the second end 146 of the cylinder block, known as top dead center, to the first end 106 of the cylinder block 74, known as bottom dead center. As each of the plurality of pistons 94 moves from top dead center to bottom dead center in the first direction of rotation R1, each of the plurality of pistons 94 draws the working fluid through the first channel 130 and into the cylinder block 74. As each of the plurality of pistons 94 moves from bottom dead center to top dead center, each of the plurality of pistons 94 pushes the working fluid out of the cylinder block 74. A first portion of the pumped working fluid is forced out of the rotating working assembly 86 through the second channel 134.A second portion of the pumped working fluid, the cooling flow 62, is forced through the third channel 138 of the valve plate 92 from the rotating working unit 86, separately from the first portion at the second channel 134 (i.e., not mixed or connected to it). The working fluid received by the third channel 138 is used as the cooling flow 62 for the integrated electro-hydraulic unit 10. As briefly mentioned above, the cooling flow 62 through the third channel 138 is separate from the first channel 130 and the second channel 134, so the volumetric efficiency measured between the first channel 130 and the second channel 134 is not affected by the cooling flow 62.

[0016] After the cooling flow 62 has been forced through the third channel 138 at the valve plate 92, it flows through the connection end housing 34 and into the cooling pipe 118, as shown in Fig. Figure 2 shows that in some embodiments, however, the terminal end housing 34 does not direct the cooling flow 62 to the cooling tube 118. For example, the cooling tube 118 or the connector 119 may be inserted directly into the third channel 138. Before the cooling flow 62 exits the cooling tube 118, it may be filtered by a magnetic connector 162 or a mesh filter 166 to remove particles from the cooling flow 62, as shown in Figure 2. Fig. Figure 2 is shown. In some cases, the magnetic connector 162 or the mains filter 166 can be placed in the terminal end housing 34 for accessibility in case the components need to be replaced. Advantages of the magnetic connector 162 and the mains filter 166 include preventing blockage or clogging of the plurality of recesses 150. The cooling flow 62 is discharged from the cooling tube 118 through the multiple recesses 150 on the surface 154. The cooling flow 62 exits the plurality of recesses 150 and enters the space 158. The cooling flow 62 flows through the cooling passage 159 between the electric machine 14 and the hydraulic machine 18 and into the space 160. The cooling flow 62 is discharged from the outlet channel 54.In further embodiments, a similar cooling passage is formed in an integrated electro-hydraulic unit 10A, but it runs through an outlet channel 54A on the radial covering 26, as in . Fig. Figure 11 is shown. The cooling flow can also be used to cool additional electronic components 170, as shown in Fig. 11 is shown.

[0017] The additional electronic components 170 may include, among other things, an inverter and / or an electronic control system.

[0018] In addition to pumping, the integrated electro-hydraulic unit 10 can also convert hydraulic force into mechanical force. In other words, the hydraulic machine or "pump" has the capability to pump, but also the capability to drive a motor. The ability to switch between pumping and motor operation is made possible by reversing the direction of rotation of the electric machine 14. A unit capable of both pumping and motor operation is commonly referred to in the field as a two-quadrant unit.

[0019] Fig. Figure 13 shows an alternative embodiment of a valve plate 92A for use with the rotating group 86, which includes a fourth channel 174. The fourth channel 174 allows cooling when the shaft 78 and the cylinder block 74 rotate counterclockwise about the axis A1 in a second direction of rotation R2, which is also referred to as engine operation. As in Fig. 12 and Fig. As shown in Figure 13, the center of the fourth channel 174 is located within a second angular span ω on the valve plate 92A in front of a second rotational position line 144. The second rotational position line 144 corresponds to top dead center. The second angular span ω is 25 degrees in some cases. Fig. In the second direction of rotation R2, the shaft 78 and the cylinder block 74 are rotated counterclockwise around the axis A1. As each of the plurality of pistons 94 moves from top dead center to bottom dead center during one rotation of the cylinder block 74, each of the plurality of pistons 94 draws the working fluid through the second channel 134 and into the cylinder block 74. To prevent the working fluid from being drawn through the third channel 138A during engine operation, a check valve 178, which is in flow communication with the third channel 138A, prevents the flow, as shown in Fig. Figure 13 shows that as each of the plurality of pistons 94 moves from bottom dead center to top dead center in the second direction of rotation R2, each piston 94 forces the working fluid out of the cylinder block 74. A third portion of the working fluid is forced out of the rotating group 86 through the first channel 130. A fourth portion of the working fluid is forced out of the rotating group 86 through the fourth channel 174 of the valve plate 92A, separately from the third portion at the first channel 130 (i.e., not mixed or connected to it). The working fluid received by the fourth channel 174 is used as the cooling flow 62 for the integrated electro-hydraulic unit 10.As briefly mentioned above, the cooling flow 62 through the fourth channel 174 is separate from the first channel 130 and the second channel 134, so that the volumetric efficiency measured between the first channel 130 and the second channel 134 is not affected by the cooling flow 62. To prevent the working fluid from being drawn through the fourth channel 174 during pumping, a check valve 180, which is in flow communication with the fourth channel 174, prevents the flow, as shown in [reference]. Fig. 13 is shown.

[0020] In summary, by placing a third channel 138 on the valve plate 92 extending from bottom dead center to top dead center, the cooling flow 62 is permitted for the first direction of rotation R1 of the cylinder block 74. Accordingly, by placing a fourth channel 174 on the valve plate 92 extending from bottom dead center to top dead center, the cooling flow 62 is permitted for the second direction of rotation R2 of the cylinder block 74.

[0021] Fig. Figure 6 shows an alternative embodiment of a valve plate 92B for use with the rotating assembly 86, which includes a fourth channel 174B. The center of the fourth channel 174B is located within the second angular span ω on the valve plate in front of the second rotational position line 144, as shown in Fig. 6 and Fig. 12 is shown. In contrast to the fourth channel 174, the fourth channel 174B cannot provide the cooling flow 62 during motor operation, since it lies within the same radial extent from top dead center to bottom dead center as the third channel 138 of Fig. 6. Instead, the fourth channel 174B contributes to the cooling flow 62 in situations where a higher cooling capacity is required. As mentioned previously, the speed of the majority of pistons 94 within the first and second angular spans Φ, ω is low compared to the maximum speed of the majority of pistons 94 and thus corresponds to a lower working fluid flow rate. The low working fluid flow rate results in less disturbance of the overall fluid flow in the integrated electrohydraulic unit 10. Furthermore, the majority of pistons 94 displace the working fluid and generate pressure differentials within the cylinder block 74. The pressure differentials within the cylinder block 74 influence the tilting moments of the cylinder block 74.By inserting the center of the fourth channel 174B within the second angular span ω, the cylinder block 74 is balanced by counteracting the effect that the third channel 138 has on the pressure differences in the cylinder block 74. Thus, the effect of pressure on the tilting moments of the cylinder block 74 is weakened.

[0022] Fig. Figure 7 shows an alternative embodiment of a valve plate 92C for use with the rotating assembly 86, comprising a third channel 138C positioned radially offset (outwardly) from the pitch circle 182 of the first channel 130 and the second channel 134. The center of the third channel 138C is located within the first angular span Φ on the valve plate 92C past the first rotational position line 142, as shown in Fig. 7 and Fig. Figure 12 shows that the valve plate 92C operates with a different embodiment of the cylinder block end 190. The plate compatible with the valve plate 92C consists of slots in the shape of an overlap between the slots 190 and the third channel 138C. The majority of the slots are shaped differently from the majority of the slots 190 to accommodate the offset radial positioning of 138C. The alternative location for the third channel 138C allows the cooling flow 62 to be controlled more easily because the area of ​​the third channel 138C that communicates with the majority of the slots 192C of the cylinder block end 190C is reduced compared to the third channel 138C used in the cylinder block end 190. In other words, the overlap span between the slots 192C and the third channel 138C can be smaller compared to the overlap span of the cylinder block end 190 and the third channel 138.Furthermore, the pressures in the cylinder block 74 are constant because the slots have similar shapes.

[0023] Fig. Figure 8A shows an alternative embodiment of a valve plate 92D for use with the rotating assembly 86. The valve plate 92D includes a third channel 138D, which is offset radially inward from the pitch circle 182 of the first channel 130. The center of the third channel 138D is located within an angular span Φ of the second channel 134. The valve plate 92D operates with a different embodiment of the cylinder block end 190 for the cylinder block 74, as shown in Figure 8A. Fig. 9A is shown. A cylinder block end 190D has the majority of slots 192 around the axis A1, with one slot 193 being offset (inwards) from the pitch circle 182. The slot 193 is only connected to the third channel 138D. In contrast to Fig. The pressures in cylinder block 74 are not constant because slot 193 is only connected to the third channel 138D and slot 193 has a different size than the other slots 192. An advantage of the design of slot 193 is greater control over the working fluid added to the cooling flow 62.

[0024] Fig. Figure 8B shows an alternative embodiment of the valve plate 92E for use with the rotating group 86. The valve plate 92E comprises a third channel 138E and a fourth channel 174E within the angular span Φ of the second channel 134 and on a pitch circle 186 common with the third channel 138E. The valve plate 92E operates with a different embodiment of the cylinder block end 190 for the cylinder block 74, as shown in Fig. Figure 9B shows that a cylinder block end 190E has the majority of slots 192 positioned on the pitch circle 182. The cylinder block end 190E also has slot 193 and slot 194 positioned inwards from the pitch circle 182, as shown in Figure 9B. Fig. 9B is shown to match the pitch circle 186 of the third channel 138E and the fourth channel 174E. As in Fig. 8A the pressures in the cylinder block 74 are not constant, since the slots 193, 194 are only in flow communication with the third and fourth channels 138E, 174E.

[0025] Fig. 15 represents an alternative embodiment of an integrated electro-hydraulic unit 200. Fig. Figure 16 represents an alternative embodiment of a drive flange 201 in the integrated electro-hydraulic unit 200 (along line 16-16). The drive flange 201 is arranged radially from axis A1 between an electric machine 204 and a cylinder block 208. The drive flange 201 is configured to define an interface between the electric machine 204 and the cylinder block 208, so that power is transferred from the electric machine 204 to the cylinder block 208 and vice versa. The cylinder block 208 is compatible with the working group 86 as described above. The electric machine 204 comprises a stator 212 and a rotor 216. The rotor 216 is constructed from a plurality of stacked metal plates 220. The rotor 216 defines an axial extent S1, which is measured parallel to the axis A1 between a first axial end 224 and a second axial end 228.The cylinder block 208 has a different construction than the rotor 216. For example, the cylinder block 208 has a uniform or monolithic construction. The cylinder block 208 includes a distal section 232, which is radially spaced from the axis A1. The distal section 232 defines an axial extension S2, which is measured parallel to the axis A1 between a first axial end 236 and a second axial end 240 of the distal section 232. The axial extensions S1, S2 of the rotor 216 and the distal section 232 do not correspond in size and / or position (e.g., the axial extension S1 is larger than the axial extension S2). Thus, the drive flange 201 is provided as a radially interposed adapter configured to transmit rotation between the rotor 216 and the distal section 232.

[0026] As shown, at least one section of the axial extension S2 of the distal section 232 axially overlaps at least one section of the axial extension S1 of the rotor 216. Within the overlapping sections of the axial extensions S1 and S2, a radial reference line (not shown) extending from axis A1 intersects both the rotor 216 and the distal section 232 of the cylinder block 208. The axial extension S2 of the distal section 232 near the first axial end 236 of the distal section 232 extends outside the axial extension S1 near the first axial end 224 of the rotor 216. The center of the axial extension S2 of the distal section 232 is axially offset from the center of the axial extension S1 of the rotor 216. A small part of the axial extent S1 of the rotor 216 overlaps the axial extent S2 of the distal section 232.A large part of the axial extent S2 of the distal section 232 overlaps the axial extent S1 of the rotor 216.

[0027] Fig. Figure 17 represents only the drive flange 201. The drive flange 201 includes a rotor receiving section 244 configured to support the rotor 216. The rotor receiving section 244 has a length corresponding to the axial extent S1 of the rotor 216. The rotor receiving section 244 is located radially outside and may be formed by a cylindrical outer surface of the drive flange 201. The drive flange 201 includes a first keyway 248 and a second keyway 252, which are diametrically opposed to each other. As shown, both the first and second keyways 248, 252 intersect the rotor receiving section 244, such that they are configured to interact with an interior of the rotor 216. The first keyway 248 and the second keyway 252 are diametrically opposite each other, so that the keyways 248 and 252 are arranged symmetrically around the axis A1.In other designs, the drive flange 201 includes more than two keyways arranged symmetrically around the axis A1. The symmetry of the keyways 248 and 252 ensures that the drive flange 201 is balanced, thus maintaining the equilibrium of the working group 86. The majority of stacked metal plates 220 of the rotor 216 include corresponding keyways (not shown). The drive flange 201 includes a stepped projection 256 that extends radially outward and is positioned axially between a first axial end 266 and the rotor receiving section 244 of the drive flange 201. The drive flange 201 includes a groove 264 positioned at a second axial end 268 of the drive flange 201. The groove 264, which extends circumferentially around the axis A1, is formed immediately adjacent to the rotor receiving section 244. The groove 264 is configured to accommodate a split ring 272 as shown in . Fig. 16 to accommodate the axial holding of the rotor 216.

[0028] The rotor 216 is attached to the rotor mounting section 244 of the drive flange 201 by sliding the majority of stacked metal plates 220 onto the rotor mounting section 244 in such a way that the first axial end 224 of the rotor 216 abuts the recessed projection 256 and the second axial end 228 of the rotor 216 is axially restricted against removal by the split ring 272. A first and a second key (not shown) are inserted into the first keyway 248, the second keyway 252 and the keyways (not shown) so that the rotor 216 and the drive flange 201 are rotatably coupled.

[0029] Fig. 17 and Fig. Figure 18 represents the drive flange 201, which includes a cylinder block receiving inner section 276 configured to receive the distal section 232 of the cylinder block 208. The portion of the cylinder block 208 that provides the distal section 232 is in Fig. Figure 18 added in dashed lines. The cylinder block receiving inner section 276 has a length corresponding to the axial extent S2 of the distal section 232 of the cylinder block 208. In other designs, the length of the cylinder block receiving inner section 276 is equal to the axial extent S2 of the distal section 232 of the cylinder block 208 ± 5%, so that a large portion of the axial extent S2 overlaps the inner section 276. In the design shown, the cylinder block receiving inner section 276 is defined by an area with a locally greater wall thickness and is the only inner section of the drive flange 201 configured to support the distal section 232 of the cylinder block 208. The cylinder block receiving inner section 276 comprises shrink-fit interfaces F at a first axial end 278 and a second axial end 280 of the cylinder block receiving inner section 276.The distal section 232 is coupled to the cylinder block receiving inner section 276 via a tight fit. A diameter D1 of the shrink-fit interface F is configured to be slightly smaller than a diameter D2 of the distal section 232, as shown in . Fig. Figure 18 is exaggerated. To install the drive flange 201 with the cylinder block 208 via the tight fit, the distal section 232 is cooled to reduce the diameter D2, and the drive flange 201 is heated to increase the diameter D1. The changes in diameters D1 and D2 allow the cylinder block 208 to fit into the drive flange 201. When the cylinder block 208 and the drive flange 201 reach temperature equilibrium, the diameter D1 returns to a slightly smaller size than the diameter D2, so that the cylinder block 208 and the drive flange 201 are held together by a tight fit. In further designs, the distal section 232 of the cylinder block is press-fitted into the cylinder block receiving inner section 276 of the drive flange 201.The second axial end 240 of the distal section 232 of the cylinder block 208 comprises surfaces with rounded edges that are in contact with the shrink-fit interfaces F of the cylinder block receiving inner section 276.

[0030] The cylinder block receiving inner section 276 further comprises a circumferential pocket 284. The pocket 284 is configured to receive adhesive for securing the distal section 232 of the cylinder block 208 to the cylinder block receiving inner section 276. The pocket 284 has a diameter D3 that is larger than D1 and is located axially between the shrink-fit interface F. In other designs, the diameter D3 is at least 0.10 millimeters larger than the diameter D1 of the shrink-fit interface F to allow space for the adhesive. The diameter D3 relative to the diameter D1 (i.e., the depth of the pocket 284) is described in Fig.Figure 18 is exaggerated for illustrative purposes. The adhesive is applied before the tight fit between the drive flange 201 and the cylinder block 208. In other designs, the adhesive is applied after the tight fit is complete by injecting the adhesive through recesses 288. The recesses 288 are diametrically opposed to each other, so that they are symmetrical about axis A1 to maintain the balance of the working group 86. The recesses 288 are configured to align with recesses 292 on the distal section 232. In other designs, fasteners 296 extend through the recesses 288 and 292 to couple the drive flange 201 to the cylinder block 208 without the use of adhesive. In other designs, the fastening means 296 couple the drive flange 201 to the cylinder block 208 in addition to bonding the drive flange 201 and the cylinder block 208.

[0031] Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope of protection and concept of one or more independent aspects of the invention as described.

Claims

[1] Integrated electro-hydraulic unit comprising: a hydraulic machine comprising a shaft and a cylinder block coupled to the shaft, the shaft configured to rotate about a central axis, the cylinder block having a plurality of pistons within the cylinder block, the cylinder block configured to rotate about the central axis to produce a reciprocating motion of each of the plurality of pistons, the cylinder block having a distal portion spaced from the central axis, the distal portion having an axial extent measured parallel to the central axis between a first and a second axial end of the distal portion; an electric machine comprising a stator and a rotor comprising a plurality of rotor plates, the rotor having an axial extent measured parallel to the central axis between the first and a second axial end of the rotor, the axial extent of the rotor being greater than the axial extent of the distal portion of the cylinder block; and a drive flange located radially outward of the cylinder block and radially inward of the rotor to define an interface between the distal portion of the cylinder block and the rotor, wherein the plurality of stacked plates are secured to a rotor receiving outer portion of the drive flange and the distal portion of the cylinder block is secured to a cylinder block receiving inner portion of the drive flange, and wherein the axial extent of the distal portion of the cylinder block extends outside the axial extent of the rotor. [2] Integrated electro-hydraulic unit according to claim 1, wherein the cylinder block receiving inner portion of the drive flange is defined by a region with a locally greater wall thickness, the cylinder block receiving inner portion having an axial length corresponding to the axial extent of the distal portion of the cylinder block. [3] The integrated electro-hydraulic unit of claim 1, wherein the axial extent of the distal portion of the cylinder block and the axial extent of the rotor have axially overlapping portions, wherein a radial reference line extending from the central axis intersects both the distal portion of the cylinder block and the rotor. [4] The integrated electro-hydraulic unit according to claim 1, wherein the drive flange further comprises a first keyway and a second keyway, the first and second keyways being formed to intersect the rotor receiving portion, the first keyway and the second keyway being diametrically opposed to each other around the central axis. [5] The integrated electro-hydraulic unit of claim 1, wherein the drive flange further comprises a stepped projection projecting radially outward, and wherein the first axial end of the rotor abuts the stepped projection. [6] The integrated electro-hydraulic unit of claim 1, wherein the drive flange further comprises a circumferential groove formed in the rotor receiving outer portion about the central axis, the circumferential groove receiving a split ring for abutting the second axial end of the rotor. [7] The integrated electro-hydraulic unit of claim 1, wherein the drive flange further comprises a circumferential pocket formed in the cylinder block receiving inner portion. [8] The integrated electro-hydraulic unit of claim 7, wherein the distal portion of the cylinder block is secured to the cylinder block receiving inner portion by adhesive in the circumferential pocket. [9] The integrated electro-hydraulic unit of claim 1, wherein the drive flange further comprises a recess positioned to intersect the distal portion of the cylinder block, the integrated electro-hydraulic unit further comprising a fastener extending radially inward through the recess and into contact with the distal portion of the cylinder block. [10] The integrated electro-hydraulic unit of claim 1, wherein the drive flange is coupled to the distal portion of the cylinder block via an interference fit. [11] Integrated electro-hydraulic unit according to claim 1, wherein the cylinder block has a monolithic construction. [12] Integrated electro-hydraulic unit comprising: a hydraulic machine comprising a shaft and a cylinder block coupled to the shaft, the shaft configured to rotate about a central axis, the cylinder block having a plurality of pistons within the cylinder block, the cylinder block configured to rotate about the central axis to produce a reciprocating motion of each of the plurality of pistons, the cylinder block having a distal portion spaced from the central axis, the distal portion having an axial extent measured parallel to the central axis between a first and a second axial end of the distal portion; an electric machine comprising a stator and a rotor comprising a plurality of rotor plates, the rotor having an axial extent measured parallel to the central axis between the first and a second axial end of the rotor; and a drive flange located radially outside the cylinder block and radially inside the rotor to define an interface between the cylinder block and the rotor, wherein the plurality of stacked plates are secured to a rotor receiving outer portion of the drive flange and the distal portion of the cylinder block is secured to a cylinder block receiving inner portion of the drive flange, and wherein the first end of the distal portion of the cylinder block lies axially within the axial extent of the rotor and the second end of the distal portion of the cylinder block lies axially outside the axial extent of the rotor, such that only a portion of the axial extent of the distal portion of the cylinder block overlies the axial extent of the rotor. [13] Integrated electro-hydraulic unit according to claim 12, wherein the axial extent of the rotor is greater than the axial extent of the distal portion of the cylinder block. [14] The integrated electro-hydraulic unit of claim 12, wherein a center of axial extent of the rotor is axially offset from a center of axial extent of the distal portion of the cylinder block. [15] An integrated electro-hydraulic unit according to claim 12, wherein a small part of the axial extent of the rotor overlaps the axial extent of the distal portion of the cylinder block. [16] An integrated electro-hydraulic unit according to claim 12, wherein a majority of the axial extent of the distal portion of the cylinder block overlaps the axial extent of the rotor.

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