Electro-hydraulic machine with integrated sensor

Abstract

An electro-hydraulic motor-pump unit, MPU, having a pump for conveying a hydraulic fluid in a hydraulic system, an electric motor coupled to the pump for driving, a control coupled to the electric motor and arranged for actuating and/or feedback-controlling the electric motor, and a housing, wherein at least one sensor is disposed in a sensor receiving means integrated in the housing and is electrically connected with the control. Additionally, the invention relates to a hydraulic system comprising hydraulic lines and connected to the hydraulic lines an MPU of the invention with at least one integrated pressure sensor.

Claims

1. An electro-hydraulic motor-pump unit, MPU, comprising: a pump for conveying a fluid; an electric motor coupled to the pump for driving; a control coupled to the electric motor and arranged for actuating the electric motor; a housing; and at least one sensor electrically connected to the control and disposed in a sensor receiving means integrated in the housing, wherein the housing has a pump housing part in which functional elements of the pump are received, a motor housing part in which functional elements of the electric motor are received, and a control housing part in which functional elements of the control are received, and wherein the sensor receiving means is a structural constituent of, and exclusive to, the pump housing part.

2. The MPU according to claim 1, wherein the at least one sensor is shielded from the outside by the housing.

3. The MPU according to claim 1, wherein the at least one sensor is a pressure sensor which is in pressure-sensory contact with fluid conveyed during operation of the MPU at a fluid port of the MPU.

4. The MPU according to claim 1, wherein the pump is an internal gear pump and the at least one sensor is a pressure sensor, wherein the at least one pressure sensor is in pres sure-sensory contact with the fluid in an axial pressure field of the pump.

5. The MPU according to claim 3, wherein the sensor receiving means in the housing is configured such that a pressure-capturing area of the pressure sensor can capture the pressure in the fluid directly or via an auxiliary bore.

6. The MPU according to claim 1, wherein the pump housing part has a motor-side pump flange for connection with the motor housing part.

7. The MPU according to claim 6, wherein an interior of the pump housing part is closed with a pump lid on a side of the pump located axially opposite to the motor-side pump flange.

8. The MPU according to claim 6, wherein a suction-side and a pressure-side fluid port are respectively located either at the pump housing part or at a pump lid.

9. The MPU according to claim 1, wherein the pump housing part forms one end of the housing of the MPU, and wherein the pump housing part on the motor side is axially closed with a pump-side motor flange of the motor housing part.

10. The MPU according to claim 1, wherein the sensor receiving means extends orthogonally to a longitudinal axis of the MPU defined by the electric motor and the pump.

11. The MPU according to claim 1, wherein the sensor receiving means extends coaxially to a longitudinal axis defined by the electric motor and the pump through the pump housing part.

12. The MPU according to claim 1, wherein the MPU has an electrical contact bridge for the at least one sensor, and wherein the contact bridge extends axially through the electric motor and connects electrical ports of the at least one sensor and associated electrical ports of the control.

13. The MPU according to claim 12, wherein the electrical contact bridge is formed of form-stable elements having integrated electrical conductor paths extending in a longitudinal direction of the MPU, which are overmold or potted with an electrically insulating plastic material and are L-shaped, such that the conductor paths on the pump side form first contacts for electrical ports of the at least one sensor and on the control side second contacts for electrical ports at the control.

14. The MPU according to claim 1, wherein the control has a data interface to a communication bus, and is arranged to supply fluid pressure captured on part of the at least one sensor to the communication bus.

15. The MPU according to claim 1, wherein the at least one sensor comprises at least two pressure sensors that are integrated in the housing of the MPU, wherein a first pressure sensor for capturing pressure in the fluid is in pressure-sensory connection at a first fluid port of the pump and a second pressure sensor for capturing the pressure in the fluid is in pressure-sensory connection at a second fluid port of the pump.

16. A hydraulic system comprising hydraulic lines, and connected to the hydraulic lines, an MPU according to claim 1 with at least one integrated pressure sensor.

Description

(1) Further advantages, features and details of the invention will result from the following description, in which exemplary embodiments of the invention will be described in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually per se or in arbitrary combination. Likewise, the hereinabove mentioned features and those specified hereinbelow may be employed each per se or in groups in arbitrary combination. Functionally similar or identical members or components are furnished in part with the same reference signs. The terms left, right, above and below used in the description of the embodiment examples relate to the drawings as oriented with the figure designation or reference signs in the normally legible way. The shown and described embodiment is not to be understood as exhaustive, but has an exemplary character for explaining the invention. The detailed description primarily is for the skilled person's information, so that known circuits, structures and methods are not shown or explained in detail in the description so as not to impede the understanding of the present description. Hereinafter the invention will be described by way of example with reference to the accompanying drawings. Therein are shown:

(2) FIG. 1 a schematic sectional representation of the integral arrangement of a pressure sensor in an MPU according to a first embodiment;

(3) FIG. 2 a schematic sectional representation of the integral arrangement of a pressure sensor in an MPU according to an alternative embodiment;

(4) FIG. 3 a perspective view of an MPU according to the first embodiment;

(5) FIG. 4 the perspective view of the MPU of FIG. 3 with the pump housing part omitted;

(6) FIG. 5 the perspective representation of the MPU of FIG. 4 with the motor housing part omitted;

(7) FIG. 6 a perspective view of the MPU of FIGS. 3-5 without electronic drive unit and without motor housing;

(8) FIG. 7 a sectional representation of the MPU of FIGS. 3-6;

(9) FIG. 8 a perspective representation of the MPU of FIG. 3 without electronic drive unit and thus with a view onto the interface between motor unit and electronic drive unit.

(10) In the hereinafter described embodiment examples the sensor integrated in an MPU is a pressure sensor. This, however, is not to be understood such that the integration of a sensor in an MPU as suggested herein is restricted to pressure sensors. Rather, also other sensors can be advantageously integrated in an MPU in the manner suggested herein.

(11) The FIGS. 1 and 2 respectively show a schematic sectional representation with an integral arrangement of a pressure sensor in an electro-hydraulic motor-pump unit, MPU 1, 2 according to a first and according to an alternative embodiment.

(12) The MPU 1 of FIG. 1 and the MPU 2 of FIG. 2 substantially consist of three functional units: a pump unit 100 with a pump 10 for conveying a hydraulic fluid in a hydraulic system HS; a drive unit 200 having an electric motor 20 and coupled to the pump unit 100 for driving the pump 10; and a control unit 300 having a control 30 and coupled to the drive unit 200 and arranged for actuating or feedback-controlling the electric motor 20.

(13) The control 30 is arranged for controlling (or feedback-controlling) the electric motor 20 and for energizing the pressure sensor 70 and for requesting a sensor signal supplied by the pressure sensor 70. The pressure sensor 70 can be, depending on the underlying physical principle, a piezoresistive or piezoelectric pressure sensor, a Hall element, a capacitive or inductive pressure sensor; basically, also other physical principles not mentioned herein or future ones are conceivable for the pressure measurement in a sensor to be integrated into the MPU.

(14) The pump 10, the electric motor 20 and the control 30 are housed by a housing 50 of the respective MPU 1, 2. As already explained at the outset, housing 50 here is understood to be the part of the MPU 1, 2 which protectively receives and holds the pump 10, the electric motor 20, the control 30 etc. of the MPU 1, 2. The feature housing 50 in connection with the present invention is not to be understood as restricted to the envelope of the MPU 1, 2 visible from outside. The feature housing 50 also comprises structures in the interior of the MPU 1, 2 which are integral to the constituents forming the envelope of the MPU or are connected thereto. Structures in the interior of the MPU 1, 2 may be, for example, inner walls, braces, etc., but also flange parts for connecting two functional units or two parts of a multipart functional unit. I. e., the housing 50 is formed by such parts of the MPU 1, 2 which receive, envelop or at least hold functional elements of the functional units 100, 200, 300 of the MPU.

(15) The housing 50 of the MPU 1, 2 consists of several housing parts 51, 52, 53 which together form the housing 50 of the MPU 1, 2. In the variants of the FIGS. 1 and 2, the housing parts are a pump housing 51 for receiving the functional components of the pump 10, a motor housing 52 for receiving the functional components of the electric motor 20 and a control housing 53 for receiving the components of the control 30.

(16) Basically, at least one housing part (pump housing 51, the motor housing 52 and the control housing 53) can be one- or multi-part. In the implementations of the FIGS. 1 and 2, the pump housing 51 is of two-part design and has a housing lid 51a and a pump housing part 51b.

(17) It should be noted that the pump housing 51 can have only the pump housing part 51b which then forms one end of the housing 50 of the MPU 1, 2. In this case, the pump housing part 51b can then be axially closed on the motor side with a pump-side motor flange of the motor housing 52.

(18) The pump housing part 51b defines in its interior the space for receiving the functional parts of the pump 10 for the conveyance of the hydraulic fluid and for the drivingly coupling to the electric motor 20. The pump 10 is coupled to the electric motor 20 via a drive shaft W led through a motor-side pump flange.

(19) In both implementations at least one pressure sensor 70 is integrated in the housing 50 of the MPU 1, 2 by the pressure sensor 70 being disposed in a sensor receiving means 80 integrated in the housing 50. This achieves that with a mounted MPU 1, 2 the pressure sensor 70 is not accessible through the housing 50 from outside and thus shielded from environmental influences. The sensor receiving means 80 is an integral constituent of the housing 50 of the MPU 1, 2. Thus, the pressure sensor 70 located in the sensor receiving means 80 is integrated in the housing 50 of the MPU 1, 2.

(20) In the embodiment of FIG. 1, the pressure sensor 70 is electrically connected with the control 30 via a contact bridge 90 through the motor unit 200. In the embodiment of FIG. 2, the pressure sensor 70 is electrically connected directly with the control 30 arranged adjacent to the pressure sensor 70.

(21) The pressure sensor 70 located in the sensor receiving means 80 is at a hydraulic port 41 of the MPU 1, 2 in pressure-sensory contact with the hydraulic fluid conveyed by means of the pump 10 during operation of the MPU 1, 2 in order to capture the hydraulic pressure present there in the hydraulic fluid. For capturing the pressure, the pressure sensor 70 has a pressure-capturing area 73 via which the pressure sensor 70 during operation of the MPU 1, 2 with the hydraulic fluid flowing through the pump 10 is in contact with the hydraulic fluid-containing interior of one of the hydraulic ports 40 of the MPU 1, 2 via an auxiliary bore 85 which connects the interior of the hydraulic port 41 with the sensor receiving means 80.

(22) Between pump lid 51a and pump housing part 51b or, if the pump housing consists of only the pump housing part 51b, between pump housing part 51b and the pressure sensor 70 there is disposed a seal not shown in the FIG. 1 to seal the sensor receiving means 80 against the hydraulic fluid.

(23) When the pump 10 is a displacement pump in the form of an internal gear pump, the pressure sensor 70 can be in pressure-sensory contact with an axial pressure field of the pump alternatively directly or via an auxiliary bore.

(24) In the schematic sectional representation of FIG. 1 an MPU-integral arrangement of a pressure sensor 70 according to the first embodiment is shown. Here the sensor receiving means 80 extends coaxially to a longitudinal axis LA of the MPU 1 defined by the electric motor 20 and the pump 10 through the pump housing part 51b. The sensor receiving means 80 extends axially as a through hole through the pump housing part 51b and is thus integrated in the pump housing part 51b.

(25) At a first open end 81 the sensor receiving means 80 is closed by means of the pump lid 51a. The pressure sensor 70 is inserted in the sensor receiving means 80 from the direction of the pump lid 51a similar to a cartridge in a cartridge chamber, such that its pressure-sensitive sensor area 73 is oriented in the direction of the pump lid. Alternatively, the pressure sensor 70 can also be screwed via corresponding threads at the sensor and at the sensor receiving means in the pump housing part 51b. At the pump lid 51a there are located two hydraulic ports 41, 42 of the pump 10. In the pump lid 51a there is provided an auxiliary bore 85 via which, during operation of the MPU 1, a pressure-sensory contact between a sensor area of the pressure sensor 70 with the hydraulic fluid at the hydraulic port 41 is established.

(26) A second open end 82 of the sensor receiving means 80 may be superimposed by a through hole in a pump-side motor flange to contact electrical ports of the sensor 70 located on this side. When the pump housing part 51b has a motor-side pump flange, the electrical ports of the pressure sensor 70 are contactable already on account of the sensor receiving means 80 in the form of the through hole.

(27) In the embodiment of FIG. 1 the control housing 53 of the control unit 300 is connected preferably axially with the motor housing 52 at the motor housing 52 end opposing the pump unit 100 via a control-side motor flange or a motor-side control housing flange.

(28) For electrically connecting the pressure sensor 70 with the control 30 there are provided contact bridges 90 as fasteners which produce an electrical connection through the motor housing 52 between electrical contacts of the pressure sensor 70 and corresponding electrical contacts at a circuit board 31 of the control 30 in the control housing 53.

(29) In the schematic sectional representation of FIG. 2 an MPU-integral arrangement of a pressure sensor 70 according to an alternative embodiment is shown. Here the sensor receiving means 80 extends orthogonally to the longitudinal axis LA of the MPU 2 defined by the electric motor 20 and the pump 10 in the pump housing part 51b.

(30) The sensor receiving means 80 is integrated as a blind hole radially to the longitudinal axis of the MPU 2 in the pump housing part 51b such that in an assembled MPU 2 an open end 82 of the sensor receiving means 80 is closed by means of the control housing part 53 of the control 30. At the end 81 opposing the open end 82 the sensor receiving means 80 is connected with the interior of the hydraulic port 41 via the auxiliary bore 85. Here, too, the pressure sensor 70 can be screwed via corresponding threads at the sensor 70 and at the sensor receiving means 80 in the pump housing part 51b.

(31) In this embodiment too, for sealing the sensor receiving means 80 there is disposed a seal (not shown in FIG. 2) between pressure sensor 70 and pump housing part 51b to seal the sensor receiving means 80 against the hydraulic fluid.

(32) In this embodiment too, when the pump 10 is a displacement pump in the form of an internal gear pump, the pressure sensor 70 can be in pressure-sensory contact with an axial pressure field of the pump alternatively directly or via an auxiliary bore.

(33) The control housing 53 in this embodiment is connected, accordingly with reference to the longitudinal axis LA of the MPU 2 defined by the pump 10 and the electric motor 20, radially at the side at least with the pump housing part 51b and with the motor housing part 52.

(34) For the functional electrical connection of the electrical ports of the pressure sensor 70 with the control 30, in the second embodiment these can be in a direct electrical contact or likewise via intermediate fasteners in a preferably spring-loaded or plugged-in contact with contact points at a circuit board of the control 30.

(35) In the following, with reference to FIGS. 3 to 8 there is explained in detail a preferred embodiment example of an MPU 1 which substantially corresponds to the embodiment in FIG. 1.

(36) FIG. 3 shows a perspective view of the MPU 1. The MPU 1 consists of the pump unit 100 with a pump 10 for conveying a hydraulic fluid in a hydraulic system, a motor unit 200 coupled to the pump unit 100 for driving the pump 10, a control unit 300 coupled to the motor unit 200 and arranged for actuating the electric motor. All functional units are enveloped by a housing 50 of the MPU 1.

(37) The housing 50 is formed by several housing parts, namely the pump housing 51, the motor housing 52 and the control housing 53. The pump housing 51 is of a two-part design and consists of a pump lid 51a and a pump housing part 51b. At the pump lid 51a there are located two hydraulic ports 41, 42 of the pump unit 100.

(38) FIG. 4 shows the perspective view of the MPU 1 of FIG. 3 with the pump housing part 51b omitted. Compared to FIG. 3, in FIG. 4 there can now be recognized the two pressure sensors 71, 72 disposed in the housing 50, namely in the pump housing part 51b, shielded from the outside by the housing 50 and electrically connected with the control unit 300. By omitting the pump housing part 51b, one can readily see that the pump housing part 51b in its interior forms the space for receiving the functional parts of the pump 10 for conveying the hydraulic fluid and for the drivingly coupling to the electric motor 20.

(39) The pump is designed as an internal gear pump, in the pump housing part 51b there are thus substantially disposed: a driven pinion with external teeth, a gear ring with internal teeth engaged with the pinion and a sickle-shaped filler piece integrated fixed to the housing, which is formed symmetrically to a central plane between the pinion and the gear ring and forms gear chambers with the teeth of the pinion and the ring gear.

(40) The pump 10 is coupled to the electric motor 20 via a drive shaft led through the motor-side pump flange 51c (FIG. 6) for driving the pinion of the pump 10.

(41) For axial sealing, between the gear wheels and the pump housing part 51b on one side and the pump lid 51a on the other side there is disposed respectively one axial pressure plate (not shown) which is respectively pressed axially against pinion and gear ring by an axial pressure field generated between the axial pressure plate and the pump housing part 51b or pump lid 51a. The axial pressure plates have bores which are penetrated by a drive shaft for the pinion, and are thus disposed in a plane perpendicular to the axes of the gear wheels. An axial pressure field is formed either in a recess in the pump housing part 51b or pump lid 51a or on the side of the housing in the respective axial pressure plate and is, in comparison to the sickle (not shown), half-sickle-shaped, so that the axial pressure field respectively extends only on one side of the central plane of the sickle.

(42) Every axial pressure field is connected, for example, via a bore in the axial pressure plate with the suction chamber or pressure chamber of the pump 10, depending on the conveying direction of the pump. There is no connection between the two axial pressure fields at an axial pressure plate, i.e., depending on the conveying direction of the pump, in one axial pressure field of the axial pressure plates there is built up the high pressure generated by the pump and in the other axial pressure field the suction pressure.

(43) In the pump 10 having the form of an internal gear pump the pressure sensors 71, 72 are respectively in pressure-sensory contact with the conveyed hydraulic fluid at one of the two axial pressure fields of the pump on the side of the pump housing part. The pressure captured at the respective axial pressure field corresponds to the suction-side or the pressure-side pressure in the hydraulic fluid, respectively. Thus, in the embodiment example shown here, two pressure sensors 71, 72 are integrated in the housing 50 of the MPU 1. A first one of the pressure sensors 71 is arranged for capturing the pressure in the hydraulic fluid at a first one 41 of the hydraulic ports 40 and a second one of the pressure sensors 72 for capturing the pressure in the hydraulic fluid at a second one 42 of the hydraulic ports 40. The MPU 1 is designed as a multiquadrant machine and accordingly the pressure sensors 71, 72 capture, according to a current flow direction of the hydraulic fluid, the suction-side or the pressure-side hydraulic pressure, respectively.

(44) FIG. 5 shows the perspective representation of the MPU 1 of FIGS. 3 and 4, in comparison to FIG. 4 in addition also the motor housing part 52 being omitted. One can readily recognize here that the interior of the pump housing part 51b is closed with the pump lid 51a on the side of the pump unit 100 located axially opposite to the motor-side pump flange 51c (FIG. 6).

(45) FIG. 6 shows a perspective view of the electro-hydraulic motor-pump unit (MPU) of the FIGS. 3-5 without control unit 300 and without motor housing 52. In FIG. 6 one can readily recognize, in addition to the representations of FIGS. 3 to 5, that the pump housing part 51b has a motor-side pump flange 51c for the connection with the motor housing 52 in which the electric motor 20 is located.

(46) FIGS. 5 and 6 show the contract bridges 91, 92 for electrically connecting the pressure sensor 70 with the control unit 300. The contact bridges 91, 92 extend axially through the motor unit 200 and connect electrical ports 74, 75 of the pressure sensor 70 and associated electrical ports 32 of the control 30.

(47) The electrical contact bridges 91, 92 are elongate, form-stable elements with integrated electrical conductor paths 93. The conductor paths 93 were respectively punched out of contact plate, subsequently reshaped, and then overmold or potted with an electrically insulating plastic material.

(48) The conductor paths 93 have been formed in L-shaped manner in the shown embodiment, so that the conductor paths 93 have on the pump side first contacts 93a, 93b, 93c for associated electrical ports 73, 74, 75, 73, 74, 75 of one of the pressure sensors 71, 72 and on the control side second contacts 93a, 93b, 93c for electrical ports 32 at the control 30.

(49) By means of the electrical contact bridges 91, 92, i.e. the respective conductor paths 93, the pressure sensors 71, 72 are fed with the necessary electric power by the control 30 and the electrical pressure signal generated proportionally to the prevailing pressure at the hydraulic port 41, 42 by the respective pressure sensor 71, 72 associated therewith is requested by the control 30.

(50) By the electrical linking of the pressure sensors 71, 72 to the control 30 being effected through the motor housing 52 and therefore therein, the electrical linking of the pressure sensors 71, 72 is protected, like the pressure sensors 71, 72 themselves, by the housing 50 from environmental influences and likewise is not visible from outside.

(51) FIG. 7 shows a sectional representation through the MPU of the FIGS. 3-6. In FIG. 7 one can readily recognize that the housing 50 the MPU 1 has the pump housing part 51b in which functional parts of the pump 10 are held and housed, and in particular that the sensor receiving means 80 is structural constituent of the pump housing part 51b. The sensor receiving means 80 extends coaxially to the longitudinal axis LA defined by the motor unit 200 and the pump unit 100 as a through hole through the pump housing part 51b.

(52) The pressure sensor 70 is at one of the hydraulic ports 41, 42 of the MPU 1 via an auxiliary bore not shown in FIG. 7 in pressure-sensory contact with the hydraulic fluid conveyed during operation of the MPU 1. The sensor receiving means 80 is configured in the pump housing part 51b such that a pressure-capturing area of the pressure sensor 70 can capture the pressure in the hydraulic fluid via the not shown auxiliary bore at one of the fluid ports 41, 42.

(53) At a first open end 81 the sensor receiving means 80 is closed by means of the pump lid 51a. The pressure sensor 70 is inserted in the sensor receiving means 80 from the direction of the pump lid 51a such that its pressure-sensitive sensor area 73 is oriented in the direction of the pump lid 51b.

(54) The pressure sensor 70 and the sensor receiving means 80 have form-fittingly cooperating elements, for example a circumferential protrusion at the pressure sensor 70 and a respective circumferential edge at the sensor receiving means 80. Protrusion and edge are matched to each other such that the pressure sensor 70 inserted in the sensor receiving means 80 is fixed like a cartridge in a cartridge chamber. For sealing the sensor receiving means 80 against the hydraulic fluid an o-ring seal not shown in detail in FIG. 7 is provided.

(55) At the pump lid 51a there are located the hydraulic ports 40 of the pump 10. The hydraulic ports 40 and the sensor receiving means 80 can be designed such that the sensor area 73 of the pressure sensor 70 during operation of the MPU 1 is in direct contact with the hydraulic fluid at the associated hydraulic port 40. In the embodiment of FIGS. 3 to 8, in the pump lid there is provided an auxiliary bore not shown in FIG. 7, via which the sensor area 73 of the pressure sensor 70 during operation of the MPU 1 is in contact with the hydraulic fluid at the associated hydraulic port 40. By the pressure sensor 70 being subjected to the pressure in the hydraulic fluid during operation of the MPU 1, the pressure sensor 70 is additionally securely fixed in the sensor receiving means 80.

(56) By the pump housing part 51b in this embodiment having the motor-side pump flange 51c, the electrical ports of the pressure sensor 70 are contactable by the contact bridges 91, 92 already on account of the sensor receiving means 80 in the form of the through hole. Alternatively, the second open end 82 of the sensor receiving means 80 could be brought into congruence with a through hole in a pump-side motor flange, so that the electrical ports of the pressure sensor 70 located on this side again are contactable by means of the contact bridges 91, 92.

(57) The control housing 53 of the control unit 300 having control 30 is connected axially with the motor housing 52 at the motor housing 52 end opposing the pump unit 100 via a control-side motor flange 52c (FIG. 8). Alternatively, the connection could also be established via a motor-side control housing flange.

(58) FIG. 8 shows a perspective representation of FIG. 3 without electronic drive unit and view onto the interface between motor unit and electronic drive unit. Besides the already explained housing parts of pump lids 51a, pump housing part 51b, motor housing part 52, in FIG. 8 due to omitting the control unit 300 one can readily recognize the control-side motor housing flange 52c. In the motor housing flange 52c there are located first through openings through which electrical ports 21, 22, 23 of the windings of the electric motor 20 are led, and second through openings through which the control-side second contacts 93a, 93b, 93c of the contact bridges for electrical ports 32 at the control 30.

(59) Finally, it should be noted that the control unit 300 has a data interface not represented in the Figures for linking to a communication bus, for example a CAN bus or field bus or the like, and is arranged, besides other communication purposes, for providing hydraulic pressures captured on the part of the two pressure sensors 71, 72 to the communication bus.