ELECTROHYDRAULIC ACTUATING DEVICE WITH COOLING MODULES

Abstract

An electrohydraulic actuating device (10), having an electric motor (1) and having a pump (2) driven by said electric motor, for the operation of a hydraulic control cylinder (8) of a hydraulic unit (3) wherein the motor (1) and the hydraulic unit (3) are each accommodated in a housing part (21, 22) of a housing (20), and wherein the housing (20) is equipped, at least in sections, with outwardly pointing cooling fins (4), wherein the housing (20) has a cuboidal or rectangular cross-sectional shape with substantially straight wall sections (23) situated at least on two opposite sides, which wall sections are formed with planar depressions or cutouts (24) which are continuous in the longitudinal direction, and the cooling fins (4) are provided at least partially in the form of removable plate-like cooling modules (5) which, for the insertion and installation thereof, are adapted in terms of shape and depth to the depressions or cutouts (24) of the housing (20).

Claims

1. Electrohydraulic actuator (10) with an electrical engine (1) and pump (2) driven by this to operate a hydraulic positioning cylinder (8) of a hydraulic unit (3), where engine (1) and hydraulic unit (3) are each contained in a housing section (21, 22) of the housing (20) and where the housing (20) is installed with outwardly-pointing cooling fins (4), at least in sections, characterised in that the housing (20) has a cuboidal or rectangular cross-sectional form with essentially straight wall sections (23), at least on two opposite sides, which are formed with depressions or cut-outs (24) which are continuous in a lengthways direction, and that cooling fins (4) are installed at least partially in the form of detachable, plate-like cooling modules (5) the shape and depth of which are matched in inset and fitting to the depressions or cut-outs (24) in the housing (20).

2. Electrohydraulic actuator (10), as in claim 1, characterised in that the cooling modules (5) have a flat-backed housing side and parallel cooling fins (4) pointing parallel from the housing (20) which run continuously over the whole length of each housing section (21, 22).

3. Electrohydraulic actuator (10), according to claim 1, characterised in that the cooling fins (4) within a cooling module (5) are of different heights and/or directions.

4. Electrohydraulic actuator (10), according to claim 1, characterised in that the direction of fins (4) is coaxial to working direction x.

5. Electrohydraulic actuator (10), according to claim 1, characterised in that sections of housing (21, 22) are made as extrusion-moulded sections.

6. Electrohydraulic actuator (10), according to claim 1, characterised in that the cooling fins (4) form an externally open gap of cooling modules (5).

7. Electrohydraulic actuator (10), according to claim 1, characterised in that the cooling modules (5) are made as extrusion-moulded sections.

8. Electrohydraulic actuator (10), according to claim 1, characterised in that the cooling modules (5) are made from a different material from the housing (20).

9. Electrohydraulic actuator (10), according to claim 1, characterised in that sections of housing (21, 22) are sealed with end covers (6) which have a circumferential cross-sectional form essentially identical to the housing (20).

10. Electrohydraulic actuator (10), according to claim 1, characterised in that the flat surfaces of depressions or cut-outs (24) of housing (20) are installed with connections and/or slots for attaching components and add-on devices, in particular.

11. Electrohydraulic actuator (10), according to claim 1, characterised in that cooling modules (5) are installed in terms of the material and/or form and length of cooling fins (4) as variably interchangeable modules for the same actuator (10).

12. Electrohydraulic actuator (10), according to claim 1, characterised in that the depressions or cut-outs (24) are installed in a central area of the width of the housing (20), excluding an edge area, and that the form and orientation of cooling fins (4) are symmetrical with respect to a centre line Y for housing (20).

13. Electrohydraulic actuator (10), according to claim 1, characterised in that cooling modules (5) are shaped in an external, stomach-like curve.

14. Electrohydraulic actuator (10) according to claim 1, characterised in that a control/interface box (7) is installed for actuator (10) which is connected to the housing section (22) of engine (1) without projecting above the outer circumference of housing section (21) of hydraulic unit (3).

15. Electrohydraulic actuator (10) according to claim 1, characterised in that sections of housing (21, 22) are aligned coaxially with working direction X and with each another.

Description

[0027] The invention will be described in more detail and better understood below, where a detailed description of preferred design features follows, with references made to the drawings, in which:

[0028] FIG. 1 shows a perspective view from above of a first design feature in the invention of an electrohydraulic actuator as assembled;

[0029] FIG. 2 shows an exploded perspective view from above of the first design feature in the invention with cooling modules removed;

[0030] FIG. 3 shows a perspective view from below of the first design feature of an electrohydraulic actuator in the invention;

[0031] FIG. 4 shows a perspective view from above of a second design feature of an electrohydraulic actuator in the invention as assembled;

[0032] FIG. 5 shows an exploded perspective view from above of the second design feature of the invention with the cooling modules removed; and

[0033] FIG. 6 shows a perspective view from below of the second design feature of an electro-hydraulic actuator, as assembled.

[0034] FIGS. 1 to 3 show different perspective views of a first design feature of an electrohydraulic actuator 10 in the invention. FIG. 1 shows actuator 10 in a perspective assembled view from above, FIG. 2 shows the same design feature with cooling modules 5 removed, and FIG. 3 shows a further perspective view of electrohydraulic operating device 10 of this first design feature, this time from below.

[0035] In the first design feature, electrohydraulic actuator 10 comprises a housing 20 in an essentially cuboidal/square cross-sectional form with a first housing section 21 for a hydraulic unit 3 in the upper area and a second housing section 22 below it for electrical engine 1. The two sections of housing 21, 22 of block-like housing 20 are arranged coaxially to one another and coaxially to working direction x of actuator 10. In particular but not necessarily, actuator 10 is what is known as an air-braked device which serves to make braking systems work on a fail-safe basis, such as in cranes or lifts, for example. Electrohydraulic actuator 10 The invention is characterised by a particular design of housing 20 in a block-like and/or cuboidal form, where at least two essentially straight wall sections 23 are installed on the outside of housing 20, in the present example merely on housing section 21 of hydraulic unit 3. Straight wall sections 23 of housing 20 are made from cut-outs and/or depressions 24 which extend in level form continuously over the whole length of upper housing section 21. These depressions and/or cut-outs 24 serve to take cooling modules 5 In the invention as the exploded presentation in FIG. 2 shows.

[0036] Cooling modules 5 have a multiplicity of cooling fins 4 on a plate-like cooling module 5, where the level rear is tailored to the shape and size of depression 24 on level wall section 23 of housing 20. Cooling fins 4 serve to cool sections of housing 21, 22 which, heat up due to the internal processes within actuator 10. Electrical engine 1, installed in lower housing section 22, drives a hydraulic pump 2 of hydraulic unit 3 which in turn is contained in upper housing section 21. Inside hydraulic unit 3, hydraulic pump is connected to a positioning cylinder 8 which is actuated via corresponding controls, valves and ducts inside hydraulic unit 3, as indicated in the figures, by working direction x. Positioning cylinder 8 has a bearing sleeve 9 at the upper end of actuator 10 to connect to the systems to be actuated, such as braking systems. On the underside, as can be seen, in FIG. 3, there is a foot attachment 11 with two flange-like projections and a through-hole through which actuator 10 is installed. Electrical engine 1 is housed in the lower narrower housing section 22 of housing 20, where housing section 22 is installed with cooling fins 4 at a dog-leg-projecting wall section of the housing. These cooling fins 4 ablate the waste heat from electrical engine 1 out from the housing to the ambient air. The lower housing section 22 of electrical engine 1 is closed off with a cover 6 downwards on the underside. On one side of electrical engine 1, an interface/control unit 7 is installed to which actuator 10 is connected electrically and hydraulically.

[0037] In the invention, upper housing section 21 of hydraulic unit 3, whose external dimensions are broader, is installed in an essentially cuboidal, block-like shape with four-side walls, where at least two opposite side walls are designed essentially identical. In this example, two opposite walls, Sections 23 of upper housing section 21 have two cut-outs and/or depressions 24 which serve to take detachable cooling modules 5 as shown in the exploded view in FIG. 2. Depressions 24 for cooling modules 5 are made in a central area over approx. two thirds of the width of level wall section 23 of upper housing section 1.

[0038] In this design feature in FIGS. 1 to 3, depression 24 is installed with angled side walls in a kind of V-shape which match the corresponding shape of cooling module 5 with cooling fins 4. Cooling modules 5 are attached as detachable components to housing 20 of actuator 10. Cooling modules 5 with cooling fins 4 may be removed through it, where required, such as to fit add-on components to the housing. Detachable cooling modules 5 also have the advantage that they can be exchanged for different purposes and operating conditions, and they can also be replaced if cooling fins 4 are damaged. One considerable advantage of the modular construction of housing 20, however, is that the same housing 20 can be used for different variants and model types, as detachable cooling modules 5 and the constant, continuous cross-sectional form of the sections of housing enable different types of hydraulic units and engines to be used in the same housing.

[0039] Cooling modules 5 with their respective rows of right cooling fins and left cooling fins as in the first design feature are installed in a curved, projected form such that central cooling fins 4 in cooling module 5 are shorter than the lateral cooling fins 4 (cf. FIGS. 1 and 2). As well as detachable cooling modules 5, further cooling fins 4 are also installed in the other side walls and on lower housing section 22 installed for engine 1 which are formed in the housing walls, i.e. not as detachable cooling modules 5, but as fixed cooling fins 4. Alternatively, they may also be made as detachable modules; however, in the invention, sections of housing 21 and 22 are made out of extrusion-moulded sections, and thus have a continuous, constant cross-sectional form over their whole length: so, the same tool in the extrusion moulding device can be used for different size actuators 10 which reduces production costs considerably and enables a much broader range of variants of actuator 10. Altogether, the form of housing 20, as in the invention, with covers 6, and the flat side walls make for a very compact design. Actuators 10 are shown to be compact, block-like components, such as connections for sensors, switches, etc, which have no components, including connections for sensors, switches, etc. projecting problematically outwards. Even interface and control unit 7 is integrated with the compact design without problematically projecting further outwards than the broadest housing section 21.

[0040] FIGS. 4, 5 and 6 show different views of a second design feature of an actuator 10, as in the invention. In terms of its inner structure and components, namely hydraulic unit 3 and electrical engine 1, the second design feature is essentially identical to the first. The second design feature of the invention differs from the first in that the form of housing 20 and the position and form of cooling modules 5 are different.

[0041] Once again, housing 20 of electrohydraulic actuator 10 is made in a cuboidal or square cross-sectional shape, where sections of housing 21, 22 are made as extrusion-moulded sections. Here again, housing 20 is divided into an upper, broader, housing section 21 to accommodate hydraulic unit 3, including hydraulic pump 2 and positioning cylinder 9 and a second housing section 22 to accommodate electrical engine 1, which drives hydraulic pump 2 of hydraulic unit 3. As with the first design feature, the second design feature in the invention has continuous, constant cross-section forms of the respective sections of housing 21, 22 so it can be made using extrusion moulding. Cooling fins 4 for cooling modules 5 and fixed cooling fins on the fiat exterior to housing 20, as the outer surfaces of the wall sections of housing 20, remain continuously constant over the straddling of/respective sections of housing 21, 22. This is also the case with the two opposite flat wall sections 23 where the cut-outs and/or depressions 24 are installed to take cooling modules 5. As in the first design feature, in level wall section 23 of cut-outs/depressions 24, a series of connections and openings shown in FIG. 5 are installed in housing 20 in which connecting parts and different sensors and/or switches can be installed for actuator 10. The connections and fittings can also subsequently be used for maintenance purposes or to subsequently change add-on parts. In addition, cooling modules are installed as plate-like components with a flat rear to connect to the relevant depression and/or cut-out 24 and which are formed externally with a projecting row of cooling fins 4. Unlike with the first design feature, in this second design feature, cut-outs/depressions 24 are asymmetrical around centre line Y but are displaced unilaterally to housing 20. Correspondingly, cooling modules 5 are installed in a laterally-displaced position on the respective outer walls of housing 20. In this second design feature, cooling module 5 is not, in and of itself, symmetrical, but is installed as a conically-extending component, longer on one side and/or with higher cooling fins than on the other side. Correspondingly, cut-outs and/or depressions 24 in wall sections 23 are formed in such a way that they are shallower in the central area than on the edge of housing 20, as is clearly shown in FIGS. 5 and 6 in particular. In this second design feature, the form of housing 20 with the two sections of housing 21, 22 of actuator 10 is selected so as to give a compact component as a whole with smooth, level outer wall sections. The connecting components are integrated in compact housing 20 and covered partly by cooling modules 5 and/or contained in interface/control box 7 which is also installed as an integrated and essentially non-projecting component.

[0042] In the second design feature, actuator 10, as in the invention, is also characterised by a larger multiplicity of variants in the essentially constant outer form of sections of housing 21, 22. Different types of actuators and different sizes and/or lengths of such actuators 10 may be made with one-and-the-same extrusion moulding tool, as the form and design of housing sections 21, 22 are adapted specifically to this type of production.

[0043] Not least, the design of actuator 10, with its compact cuboidal housing 20, is optimised specifically to ablate heat from units inside. As far as both electrical engine 1 and hydraulic unit 3 are concerned, however, in the broad area, arranged with cooling fins 4, particularly with cooling modules 5, the fixed, fitted cooling fins 4 also ablate heat and cool the actuating device considerably better than the previous version.

[0044] In an alternative design feature of the invention, cooling modules 5 are attached to housing 20 using spacers. This enables the add-on equipment and components fitted behind the cooling modules to be covered by frontally-positioned cooling modules 5. The inner contour of the actuator housing is thus covered continuously from the outside and can be fully used for cooling purposes through the cooling modules and the internally-installed cooling fins. The spacers between the housing and/or the depression in the housing and the cooling modules are preferably installed in a form and using a material which is a good heat conductor.

[0045] In a further alternative design feature of the invention, a fan unit is installed to assist the cooling effect. The fan unit (not shown in the figures) is integrated in housing section 22 of engine 1, for example, and has ventilation openings which point in the direction of the cooling fins 4. The fan unit may also be inserted as a separate module between housing section 22 of engine 1 and housing section 21 of hydraulic unit 3, where it preferably has the same cross-sectional form and external contours as the other sections of housing. In a further aspect of the invention, cooling modules 5 with cooling fins 4 may have am external, plate-like cover such that the gap installed between cooling fins 4 is sealed externally. This guides the cooling air in a kind of forced flow, preferably assisted by a fan from a fan unit.

[0046] In a further advantageous design feature of the invention, cooling fins 4 of cooling modules 5 are installed such that they are flush with the adjacent outer walls of the respective sections of housing 21, 22: thus, there are no projecting cooling fins on the outside of housing 20. An alternative in this invention is that, rather than cooling fins 4 being flush, they project slightly in relation to the adjacent wall sections of housing 20.

[0047] In a further design feature of the invention, heat-conducting equipment is installed between cooling modules 5 and housing 20. Heat-conducting foils or a heat-conducting paste is applied at the points where cooling modules S connect to housing 20, for example.

[0048] The invention is not limited to the characteristics of the design features shown and includes further derivations and modifications within the scope of the appended claims.

[0049] The form and design of detachable and/or connectable cooling modules 5 may differ from those in the examples shown. Cooling modules 5 may be connected to housing 20 in different ways, preferably via detachable connections including bolts, or the like.

[0050] The external cuboidal fount of housing 20 of actuator 10, as in the invention may also vary, as long as it is of essentially cuboidal or block-shaped construction. The edge areas may or may not be slightly bevelled. The constructions presented in the design features above may, however, also vary in terms of the position and arrangement of cooling fins and cooling modules.