Abstract
An electrohydraulic actuation device is descried with an electric motor and a pump driven by the electric motor for the operation of a hydraulic unit with a positioning cylinder, a piston and a piston rod serving as actuation element and projecting from a housing, wherein the electric motor and the hydraulic unit are each housed in a housing part of the housing, wherein the housing part of the hydraulic unit is separated from and sealed off from the housing part for housing the electric motor, wherein the housing has at least in the area of the hydraulic unit a lateral enlargement in relation to the longitudinal axis X of the device, beyond the circumference of the positioning cylinder and at least along a height of a stroke of the piston.
Claims
1. Electrohydraulic actuation device with an electric motor and a pump driven by the electric motor for the operation of a hydraulic unit with a positioning cylinder, a piston and a piston rod serving as actuation element and projecting from a housing, wherein the electric motor and the hydraulic unit are each housed in a housing part of the housing, wherein the housing part of the hydraulic unit is separated from and sealed off from the housing part for housing the electric motor, wherein the housing has at least in the area of the hydraulic unit a lateral enlargement in relation to the longitudinal axis X of the device, beyond the circumference of the positioning cylinder and at least along a height of a stroke of the piston, for an integrated housing of electrical functional elements, sensors or control component parts directly in the hydraulic part of the housing laterally adjacent to the hydraulic unit, and that connections or receiving means for the functional elements are provided in the enlargement.
2. Device according to claim 1, the enlargement of the housing forms a lateral receiving area approximately rectangular in cross section for functional elements.
3. Device according to claim 1, wherein that the enlargement is provided with connection openings to an outside of the housing or directly to a terminal box for electrical connections.
4. Device according to claim 1, wherein the functional elements comprise at least a contact-free, magnetic-induction sensor, which is arranged and configured for position detection of the piston by means of at least a magnet mounted thereon.
5. Device according to claim 1, wherein the functional elements comprise at least an electric heating means which projects into the hydraulic oil of the hydraulic unit.
6. Device according to claim 1, wherein the enlargement is provided above and in continuation to a terminal box for electrical connections of the device.
7. Device according to claim 1, wherein the housing at the inside of a wall of the enlargement is provided with a recess for forming a receiving area for the electrical functional elements.
8. Device according to claim 1, wherein the electrical functional elements in the hydraulic part of the housing have an encapsulated constructional shape.
9. Device according to claim 3, wherein the connection or receiving means of the functional elements are provided in a partitioning bottom between the housing part of the hydraulic unit and the housing part of the electric motor.
Description
[0019] Further features, aspects and advantages of the present invention are described in more detail in the following by means of different embodiments of the invention with regard to the attached drawings and the Figures included therein, wherein
[0020] FIG. 1 shows a vertical sectional view of an electrohydraulic actuation device according to the prior art with a mechanical position sensor at the outside of the housing;
[0021] FIG. 2 shows a partial perspective view with housing parts, separate from one another, of an embodiment of an electrohydraulic actuation device according to the invention with integrated position sensor and heating element;
[0022] FIG. 3a shows a perspective view of an embodiment of an actuation device according to the invention with opened housing parts and a position sensor and a heating means;
[0023] FIG. 3b shows a vertical sectional view of an electrohydraulic actuation device of the embodiment of FIG. 3a;
[0024] FIG. 4a shows a perspective view of a further embodiment of an electrohydraulic actuation device according to the invention with opened housing parts and a heating means;
[0025] FIG. 4b shows a vertical sectional view of the electrohydraulic actuation device according to the embodiment of FIG. 4a with a section in the area of the heating means; and
[0026] FIG. 5 shows a partial perspective cross-sectional view of a further embodiment according to the invention of an electrohydraulic actuation device.
[0027] FIG. 1 shows an electrohydraulic actuation device 10 known from the prior art, with a housing 20, in the inside of which for one thing the hydraulic unit 3 is provided with the hydraulic pump 2 and for another thing an electric motor 1 provided in a lower housing part 22 is provided, which serves for the drive of the hydraulic pump 2. The actuation device 10 is driven by the electric motor, by means of the hydraulic oil in the upper housing part 21 with the pump 2 being put under pressure, so that a piston 5 inside a cylinder 4 moves against the force of a mechanical spring in the inside of the housing 20. Hereby, the piston rod 6 projecting outwards from the housing 20 serves as the actuation device. For detecting and controlling the position and location of the actuation device 10, so-called position sensors are used, as indicated in the example of FIG. 1 in the form of an outer mechanical switch 27. The mechanical switch 27 is linked to the outward-projecting part of the piston rod 6, so that respective end positions, like for example open and closed, of the actuation device 10 can be detected by the mechanical switch 27. In the lower housing part, which is separated and sealed off from the upper housing part 21 housing the hydraulic unit 3, there is a heating means 26 which serves to bring the device 10 to a required operating temperature when the device 10 is switched on. Hereby, it has proved disadvantageous that a relatively large amount of time is required until an operation temperature is reached by the heating 26. For another thing, the known form of the actuation device 10 has the disadvantage that the position detection must be mounted at the housing 20 from the outside, so that for one thing the risk of damage exists and for another, the exactness of the measurement of the position signals can be impaired.
[0028] An embodiment of an electrohydraulic actuation device 10 according to the invention is shown in the perspective partial view of FIG. 2 with opened housing 20. The actuation device 10 comprises here too a housing 20 consisting of at least an upper housing part 21 for housing the hydraulic unit 3 and a lower housing part 21. In FIG. 2, the upper housing part 21 is taken off from the lower housing part 22 and lifted, so that the inside of the actuation device 10 is recognizable for illustrating the invention. The lower housing part 22 serves to house an electric motor 1, which is separated from the upper housing part 21 filled with hydraulic oil by means of a sealed-off partitioning bottom 28. The housing 20 is provided with a lateral enlargement 23 in the shape such that beyond the outer circumference of the hydraulic unit 3 the housing 20 is laterally lengthened and widened around an approximately rectangular area above the terminal box 9. In this way, a receiving space results between the outer wall of the housing 20 and the outer circumference of the hydraulic unit 3, which consists of the piston-/cylinder unit and the hydraulic pump 2. With the lateral enlargement 23 formed in this way, electrical or other functional elements 7, 8 can be arranged and assembled directly in the hydraulic oil in the inside space of the upper housing part 21. For example, as an electrical functional element, a heating means 8 or a heating element in the form of a heating rod or the like can be assembled and mounted there. For another thing, a position sensor 7 can also be mounted at the place of the lateral enlargement 23, which radially slightly widens the housing 20 outwards. In the embodiment shown in FIG. 2, a heating means 8 and a contact-free, magnetic-induction sensor 7 in the form of a Reed switch are mounted, so that the functional elements 7, 8 allow both a warming-up of the hydraulic oil directly in the hydraulic oil itself and an exact position detection of the piston 5 and therefore of the piston rod 6 of the actuation device 10.
[0029] In this way, a kind of integrated technical additional function or a plurality of additional functions is provided in the electrohydraulic actuation device 10 according to the invention. The heating means 8 and/or the position sensor 7 can be housed and assembled as electrical functional elements 7, 8 in the housing area of the lateral enlargement 23 of the housing 20. The functional elements 7, 8 are therefore provided in a protected manner in the inside of the housing 20 and not vulnerable to manipulation or damage or influences from outside. By means of the proximate arrangement of a magnetic-induction sensor 7 at the piston provided with a permanent magnet (not shown in FIG. 2), of the hydraulic unit 3, a very exact position determination and an exact position signal for the control and monitoring of the actuation device 10 can also be achieved. In this embodiment of FIG. 2, in an inside wall of the housing 20 there is a kind of rectangular recess 25 which enlarges the mounting space for the electrical functional elements 7, 8 without excessively enlarging the outer dimensions of the device 10. The position sensor 7 and the heating means 8, here mounted in the enlargement 23 as examples of electrical functional elements 7, 8, are provided in an encapsulated constructional shape, that is, sealed off in relation to the hydraulic oil in the upper housing part 21. At the magnetic-induction sensor 7, for example an aluminium tube with screw side surfaces is provided, while at the heating means 8 an encapsulated tubular shape of for example stainless steel, copper or also aluminium can be present. With the housing 20 formed in this way with the lateral enlargement 23, a lateral receiving space for the functional elements 7, 8 is provided in the inside of the hydraulic area. Preferably, connection openings 24, for example in the form of holes provided with threads, are present in the enlargement, by means of which the electrical functional elements 7, 8 can be directly mounted and secured. The electrical connections are then outside of the hydraulic area, namely for example in an electric terminal box 9 positioned thereunder or in a dry area provided below a partitioning bottom 28 in which, in this example, a dry-running electric motor 1 (not shown in FIG. 2) is also housed.
[0030] FIG. 3a and FIG. 3b each show, in a perspective view (exploded) and a vertical sectional view, a further embodiment of an electrohydraulic actuation device 10 according to the invention. Here too, the housing 20 is provided on a side with an enlargement 23, which serves to house electrical functional elements 7, 8, like for example a magnetic-induction sensor 7 or a heating element 8 or other kinds of functional elements or additional modules. The enlargement 23 is provided laterally and at least along the height of the travel of the piston 5, so that a magnetic-induction position sensor 7 can be housed in the enlargement 23 in the inside of the hydraulic area of the device 10. Parallel to the travel of the piston 5, the precise, exact position of the actuation device 10 is therefore detected by a position sensor 7 positioned on the inside in the form of the magnetic-induction sensor 7. The sensor 7 has at least two switch elements or Reed contacts, which cooperate with a permanent magnet 11 mounted at the piston 5. At the piston 5, there can be a single magnet 11. Alternatively, also a plurality can be provided, for example three magnets 11 mounted at a distance from one another at an outer area of the piston 5. In the latter case, also in the case of a displacement rotation position of the piston 5 the exact respective position of the actuation device is made possible by means of the detection with the proximately arranged sensor 7 in the lateral enlargement 23. As shown in FIG. 3b, the magnets 11 can be mounted at a radial outer edge of the piston 5 toward the cylinder 4. Alternatively, the magnets 11 or the magnet 11 can be mounted at a front-end lower surface of the piston 5. In the latter case, the magnets 11 are near enough to the sensor 7, which is provided directly adjacent to them, for an exact position detection of the piston; however, they do not interfere with the function of the piston 5 in the cylinder 4, namely in particular the sealing off by means of piston sealing rings etc. On reaching the level of a Reed contact of the sensor 7, the magnetic field of the magnet 11 actuates the switch, and a position signal for position determination of the actuation device 10 and of the piston 5 or of the piston rod 6 is transmitted to a control, for example in the inside of an electric terminal box 9.
[0031] Because the magnets 11 or the magnet 11 is/are arranged at the piston 5 at an outer edge area either at a front end or at the radial outside, these are very near to the detection area of the sensor 7, which can for example be a magnetic-induction sensor or Reed contact. The sensor can therefore very exactly determine the inside position of the piston 5 in relation to the cylinder 4 and the housing 20, in order, for example, to optimize the exact control of a brake thruster device. The position of an opened brake and of a closed brake can therefore be determined just as exactly, even in the case of changing external circumstances and so, with that, of a slight displacement of the end positions of the brake thruster device. Also, in this way, exact intermediate positions can be easily determined, or the optimized monitoring of the electrohydraulic brake thruster device for a so-called reserve stroke or remaining stroke, which in some cases of application of such actuation devices 1 is essential for example for the wear of the brakes, can be considerably improved in this way. As a sensor 7, also a plurality of sensors 7 can be mounted inside the lateral enlargement 23. The sensors 7 are connected to a control and can be either adjusted in their position and location in advance by the factory, or can also be positioned such that they are subsequently changeable in position and location. In any case, due to the housing in the lateral enlargement 23, they are securely housed directly in the inside of the hydraulic part of the housing 20, 21. An adjustability, assembly or positioning of the sensors 7 in the lateral enlargement 23 can be made possible by means of corresponding openings, for example by a plug or removable parts of the housing 20.
[0032] Also in this embodiment of the FIG. 3a and FIG. 3b, the housing 20 is substantially constructed of two housing parts 21, 22, wherein this is not limiting for the invention, and more than two housing parts or only one housing part 21 can be provided. The hydraulic part of the actuation device 10, namely the pump 2 and the piston-/cylinder unit 4, 5 is provided in an upper housing part 21. The pump 2 is driven by means of an electric motor 1 in a second part 22 of the housing 20 positioned therebelow, by means of the motor drive shaft engaging/acting through a partitioning bottom 28 by means of bearings and seals and driving the pump 2 for the generation of a hydraulic pressure in the hydraulic oil of the hydraulic unit 3.
[0033] Here too, the displacement of the piston 5 takes place against a (not shown) mechanical coil spring, so that after the ending of the actuation of the pump 2 a reset into the initial position takes place automatically as shown in FIG. 3b. With the detection of the exact position of the piston 5 in the inside of the hydraulic unit 3 by means of the magnetic-induction sensor 7 likewise arranged in the hydraulic oil, in this way a very exact determination of the operating conditions in the inside of the device 10 can be provided. The quality of the position signals is also independent of outside influences and manipulations. Also, no damage of the position sensor 7 from outside can take place, as this is housed in a closed inside area, namely the space of the lateral enlargement 23, directly in the upper housing part 21 of the housing 20 of the device 10.
[0034] As in the previous embodiment of FIG. 2, also in this embodiment of FIG. 3a, FIG. 3b the lateral enlargement 23 is provided in a rectangular shape and quasi engages the terminal box 9 for the electrical connections of the device 10. The enlargement 23 has as before and as can be seen from FIG. 3a an inner recess 25 at an inside wall, which enlarges the housing space for the electrical functional elements 7, 8 or other additional modules or component parts without an excessive increase in the outer dimensions of the device 10. The lateral enlargement 23, which provides a kind of radial additional space adjacent to the area of the hydraulic unit 3, is used in this embodiment for the housing of two electrical functional elements 7, 8, namely on the one side a magnetic-induction sensor 7 and on the other side a heating means 8 in the form of a heating rod projecting parallel to the sensor 7. Both are provided in encapsulated constructional form, so thus protected they can be used in the inside of the hydraulic oil for a long-term function.
[0035] The assembly and securing of the electrical functional elements 7, 8 takes place in this embodiment by means of connection openings 24, which are inserted in a partitioning bottom 28. Therefore, for example by means of threaded connections with inner threads and outer threads, the sensors 7 and heating means 8 can be easily assembled at the inside of the housing 20 and without extra securing means. Hereby, the electrical connections are positioned outside of the upper area of the first housing part 21 filled with hydraulic oil, namely either directly in the terminal box 9 for electrical connections or in an area of the lower housing part 22 for the electric motor 1, which in this embodiment is a dry-running electric motor 1. Alternatively, the connection openings 24 can also be provided such that the signal lines and connection component parts are directed outwardly from the housing 20, so that independently of the terminal box 9 a possibility for connection at outside control means etc. is rendered possible. As also in the previous embodiment, the first housing part 21 and the second housing part 22 are provided with outside cooling fins at the outer circumference. The assembly and securing of the housing parts 21, 22 takes place by means of accordingly-shaped flange parts and threaded connections, as can be seen in FIG. 3a in the exploded perspective view. At the partitioning bottom 28 between the upper housing part 21 and the lower housing part 22, corresponding seals can be provided in order to provide a sealed constructional shape of the hydraulic unit 3 in relation to the lower housing part 22 for the electric motor 1 and possible further electrical parts.
[0036] The lateral enlargement 23 is a kind of radial, local enlargement of the housing 20 in relation to the longitudinal axis X of the electrohydraulic actuation device 10. The lateral enlargement 23 in these embodiments is provided at a side corresponding to the side at which also the electrical terminal box 9 is provided. At the part of the enlargement 23 of the housing 20 in this embodiment, cooling fins of the housing 20 are likewise provided at the outside. The upper first housing part 21 for the hydraulic unit 3 and the lower housing part 22 in this embodiment are formed as a kind of cup shape with closed sides on all sides, wherein the assembly takes place by means of correspondingly shaped and matching assembly flanges and threaded connections. The housing parts 21, 22 can also be formed differently, and the housing 20 can also be constructed from more than two parts. In the embodiment shown, as can be seen from the sectional view in FIG. 3b, the electrical terminal box 9 is formed integrally with the lower housing part 22, for example by means of a casting part. The terminal box 9 can however also be made separately from the lower housing part 22 and then threadedly connected. The lateral enlargement 23 of the housing according to the invention for electrical functional elements 7, 8 or additional component parts, can be formed as shown, with a rectangular recess 25 at the inside wall of the housing 20, or without this recess 25. The shape and kind of electrical functional elements 7, 8 can be different, likewise the number of connection openings 24 provided for such functional elements. Also, according to requirement, only one functional element, for example an electric heater 8 or a position sensor 7, can be provided.
[0037] In FIG. 4a and FIG. 4b in corresponding views, namely a perspective view with exploded view of housing parts 21, 22 (FIG. 4a) and a vertical sectional view (FIG. 4b), a further embodiment of the invention is shown. The section of the FIG. 4b is here carried out in the area of a heating means 8, so that the piston rod is not visible here. Substantially this further embodiment corresponds to the above-mentioned embodiment of FIG. 3a, FIG. 3b, with the difference that here, only a heating means 8 in the form of a heating rod projecting into the hydraulic oil is provided. The heating means 8 is here also mounted in a lateral enlargement 23 at the housing 20, namely the upper housing part 21. The heating means 8 extends along approximately half the height of the above housing part 21 and thus effects a relatively fast warming-up of the hydraulic oil during a start of operation of the electrohydraulic device 10. The heating means 8 is directly threadedly connected to a receiving opening 24 in the form of a connection opening provided with an inner thread at a partitioning bottom 28, and the electrical connections for the heat resistance of the heating means 8 are guided downwards into the area of the electrical terminal box 9 (see FIG. 4b). Otherwise, this further embodiment also substantially corresponds to the above-mentioned embodiments of the invention. An electric motor 1, preferably as a dry-running electric motor, is housed in a lower area of a housing part 22, and by means of driving the pump 2 in the hydraulic area of the hydraulic unit 3, the hydraulic oil is pressurized, so that the piston 5 is displaced upwards against the force of a coil spring (see movement arrow, FIG. 4b). The lateral radial enlargement 23 is here also realized accordingly shaped in a kind of rectangular convexity of the housing at least at the upper housing part 21 and at the flanges of the two housing parts 21, 22. Thus, a receiving area, provided lateral of the piston 5, is provided for the also optional additional modules, like for example electrical functional elements 7, 8 which are constructed in advance integrated in the hydraulic oil at this position. In this embodiment too, damage and impairment of the functional elements 7, 8 from the outside is effectively prevented in this way. A fast warming-up of the hydraulic oil is achieved by means of the heating means 8 projecting directly into the hydraulic part.
[0038] In a perspective partial cross-sectional view in FIG. 5, a further embodiment of an electrohydraulic actuation device 10 according to the invention is shown, wherein here, only the upper hydraulic part of the device 10 is shown with the hydraulic housing part 21 opened in cross section and the elements lying inside it. Regarding the basic construction and the elements of the device 10, this embodiment does not differ substantially from the above-mentioned embodiments of FIG. 2 to FIG. 4b, except that at the piston 5 in the cylinder 4 of the piston-/cylinder unit, here the permanent magnet 11 is not mounted laterally at a radial outside of the piston 5, but instead at a front end of the piston 5 facing downwards. Alternatively, the axially aligned magnet 11 can also be mounted at the upper front end of the piston 5. A substantially circular permanent magnet is inserted in a deepening or recess and bore of the piston 5. The magnet 11 is positioned in a lateral edge area of the front end of the piston 5, so that it is positioned spatially very near to the sensor 7 provided laterally in the enlargement 23. Here too, a magnetic-induction sensor 7 or another sensor can be provided, which is configured for the position detection of the piston 5 in the inside of the cylinder 4.
[0039] In the embodiment shown in FIG. 5, a so-called Reed contact is mounted as sensor 7, which can detect very exactly in each case the end positions of the piston 5, that is, for example, an upper end position and a lower end position. In the case of the application of the electrohydraulic actuation device 10 as a brake thruster device, these would be the positions brake opened and brake closed. By means of the arranging of the magnets 11 or of the single magnet 11 at the front end of the piston 5, the sealing functions and the embodiment of the piston 5 are substantially unchanged in relation to conventional such pistons 5. Only at the front end, an extra magnet 11 is provided in the form of one magnet or of a plurality of magnets 11 mounted at respective distances from one another in the outside area of the front end of the piston 5. In the embodiment of the device 10 according to the invention shown in FIG. 5, furthermore in the area of the lateral enlargement 23 at the upper end of the housing 20, 21, in this example a plug 13 is provided, by means of which an access to the sensor 7 is made possible, for example for a replacement of the sensor or an adjustment and correction of the position of the sensor 7. This plug 13 is also partly provided in the above-mentioned embodiments of the invention, but not further described there. Furthermore, at the piston rod 6 and at the partitioning bottom 28 between the hydraulic part and the dry-running electric motor positioned therebelow, in each case one bearing or a plurality of bearings 12 or a bearing unit is provided. In addition, at these areas also seals are provided which ensure a sealing of the hydraulic part 21 of the housing 20.
[0040] The heating means 8 can be an electrically driven heating rod which is provided in encapsulated constructional shape, in order to be able to effect the warming of the oil in the hydraulic oil directly. In other respects, this embodiment corresponds substantially to the previous two embodiments, and a renewed description of the corresponding components and parts which are provided with same reference signs is therefore omitted in order to avoid repetition.
[0041] According to the invention, only one functional element 7, 8 can be provided in the lateral enlargement 23 of the housing 20 with correspondingly one receiving opening 24. Alternatively, a plurality of functional elements 7, 8, also more than two, can be mounted and assembled in the lateral space of the enlargement 23. Not-used receiving openings 24 can be closed with sealing plugs. Instead of a dry-running electric motor 1, also a wet-runner can be used as motor 1. The possibilities for use, the flexibility and the variability of the electrohydraulic actuation device 10 are thereby considerably increased by means of the invention.
