COMPACT ELECTRIC LINEAR DRIVE FOR A GEAR RACK, IN PARTICULAR A HYDRAULIC VALVE, AND METHOD FOR MOUNTING THE SAME

Abstract

An electric linear drive for a gear rack including a stepping motor, a holding plate, a motor output gear, and a gearing. The holding plate, the stepping motor, the motor output gear, and the gearing form a drive unit that, together with a basic housing, form an overall housing. The overall housing has an opening for the insertion of the gear rack. Drive electronics are fixed to the holding plate such that electrical connections are present on the outside of the overall housing. The stepping motor has a rotor axis arranged parallel to the holding plate. During assembly, a rack belonging to a device to be driven can be pushed into a lateral opening of the overall housing, and the device to be driven can be connected to the overall housing. The electric linear drive is compact, allowing devices to be driven to be located close to one another.

Claims

1. A method of assembling an electric linear drive unit for a gear rack of a device to be driven, comprising: fastening a stepping motor to a flat holding plate, wherein the stepping motor has a rotor axle disposed parallel to the flat holding plate and perpendicular to the gear rack; attaching a gearing to the flat holding plate, wherein the gearing is engaged with a motor output gear wheel fastened to the rotor axle, and wherein the stepping motor, the gearing, and the flat holding plate form a drive unit; and assembling the flat holding plate with a basic housing to form an overall housing for the drive unit, wherein the stepping motor and the gearing are disposed within a volume defined by the basic housing, and wherein the overall housing has an opening to receive the gear rack for engagement with the gearing.

2. The method of claim 1 wherein the drive unit includes a counter-bearing plate, wherein the gearing includes a gear shaft, and wherein the attaching of the gearing to the flat holding plate includes mounting the gear shaft parallel to the rotor axle between the stepping motor and the counter-bearing plate.

3. The method of claim 2 wherein the gear shaft includes a first gear wheel and a second gear wheel, and wherein the method further comprises: meshing the first gear wheel with the motor output gear wheel.

4. The method of claim 3 further comprising: engaging the second gear wheel with the gear rack.

5. The method of claim 1 wherein the drive unit includes drive electronics and electrical connections for the drive electronics, and wherein the method further comprises: attaching the drive electronics to the flat holding plate, wherein the drive electronics are attached to the flat holding plate such that the electrical connections are arranged on an outside region of the overall housing.

6. The method of claim 1 wherein the assembling of the flat holding plate with the basic housing includes inserting the drive unit into the basic housing.

7. The method of claim 1 wherein, upon the assembling of the flat holding plate with the basic housing to form the overall housing, a level joint is formed between the flat holding plate and the basic housing, and wherein the method further comprises: introducing a joint sealing into the level joint to seal the overall housing.

8. The method of claim 1 wherein the drive unit includes a counter-bearing plate and a centering device, and wherein the assembling of the flat holding plate with the basic housing to form the overall housing includes assembling the flat holding plate with the basic housing so that the gear rack is positioned within the drive unit by the centering device and the counter-bearing plate.

9. An electric linear drive unit for a gear rack of a device to be driven, comprising: a flat holding plate; a stepping motor fastened to the flat holding plate, wherein the stepping motor includes a rotor axle and a motor output gear wheel fastened to the rotor axle, and wherein the rotor axle is positioned parallel to the flat holding plate and perpendicular to the gear rack; a gearing attached to the flat holding plate, wherein the gearing is engaged with the motor output gear wheel, and wherein the stepping motor, the gearing, and the flat holding plate form a drive unit; and a basic housing, wherein the stepping motor and the gearing are disposed within a volume defined by the basic housing; wherein the flat holding plate is assembled with the basic housing to form an overall housing, and wherein the overall housing has an opening to receive the gear rack for engagement with the gearing.

10. The electric linear drive unit of claim 9 further comprising: a counter-bearing plate, wherein the gearing includes a gear shaft, and wherein the gear shaft is mounted parallel to the rotor axle between the stepping motor and the counter-bearing plate.

11. The electric linear drive unit of claim 10 further comprising: a centering device, wherein the gear rack is positioned within the drive unit by the counter-bearing plate and the centering device.

12. The electric linear drive unit of claim 10 wherein the gear shaft includes a first gear wheel and a second gear wheel, wherein the first gear wheel is meshed with the motor output gear wheel, and wherein the second gear wheel is engaged with the gear rack.

13. The electric linear drive unit of claim 9 further comprising: drive electronics; and electrical connections for the drive electronics, wherein the drive electronics are attached to the flat holding plate, and wherein the electrical connections are arranged on an outside region of the overall housing.

14. The electric linear drive unit of claim 13 wherein the stepping motor includes a stator having a greatest diameter or cross-sectional width of less than 45 millimeters.

15. The electric linear drive unit of claim 14 wherein the stepping motor is arranged in a decentralized manner on the flat holding plate.

16. The electric linear drive unit of claim 15 wherein the drive electronics are arranged next to the stepping motor on the flat holding plate.

17. A method of operating an electric linear drive unit for a gear rack of a device to be driven, comprising: providing the electric linear drive unit including a flat holding plate, a stepping motor fastened to the flat holding plate, a gearing attached to the flat holding plate, and a basic housing, wherein the stepping motor includes a rotor axle positioned parallel to the flat holding plate and perpendicular to the gear rack, wherein the stepping motor, the gearing, and the flat holding plate form a drive unit, and wherein the flat holding plate is assembled with the basic housing to form an overall housing; inserting the gear rack through an opening of the overall housing for engagement with the gearing; and connecting the device to be driven to the overall housing.

18. The method of claim 17 wherein the device to be driven is a hydraulic valve device, and wherein the method further comprises: following the engagement of the gear rack with the gearing, driving the hydraulic valve device with the drive unit.

19. The method of claim 17 wherein the basic housing includes a flange seal, and wherein the connecting of the device to be driven to the overall housing includes connecting the device to be driven to the overall housing by the flange seal.

20. The method of claim 17 wherein the electric linear drive unit is one of a plurality of similar electric linear drive units, wherein each of the plurality of similar electric linear drive units includes a flat holding plate, wherein each of the plurality of similar electric linear drive units have a rectangular shape in a plane of the flat holding plate and a reduced height in a direction perpendicular to the plane of the flat holding plate, and wherein the method further comprises: positioning the plurality of similar electric linear drive units adjacent to one another in a slice-type manner.

20.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The foregoing and other objects, features and advantages will be apparent from the following description of particular embodiments of the present disclosure, as illustrated in the accompanying drawings, in which like reference characters refer to the same parts throughout the different views.

[0026] FIG. 1 shows a schematic exploded diagram of the components of an exemplary embodiment of a linear drive according to the present disclosure, prior to assembling,

[0027] FIG. 2 shows a partially sectional view from above of a linear drive according to the present disclosure, with a device to be driven,

[0028] FIG. 3 shows a cross section through the arrangement according to FIG. 1 inside the overall housing, with a view of the components arranged therein,

[0029] FIG. 4 shows mechanical components of a drive unit, in a schematic view, prior to assembling,

[0030] FIG. 5 shows a lateral view of the basic housing and mounted drive unit, prior to them being assembled,

[0031] FIG. 6 shows a finished, mounted drive unit, in a schematic, lateral, partially sectional view, and

[0032] FIG. 7 shows a further exemplary embodiment of a finished, mounted drive unit, in a schematic, partially sectional view, with a gear rack that is guided by a counter-bearing and provided with joint.

DETAILED DESCRIPTION

[0033] The disclosure of U.S. patent application Ser. No. 15/746,172 filed Jan. 19, 2018 entitled COMPACT ELECTRIC LINEAR DRIVE FOR A GEAR RACK, IN PARTICULAR A HYDRAULIC VALVE, AND METHOD FOR MOUNTING THE SAME is hereby incorporated herein by reference in its entirety.

[0034] FIG. 1, in the form of an exploded diagram, shows the essential parts of the linear drive 1 according to the present disclosure for a gear rack 3 and its action in combination with a device 2 to be driven, from which the gear rack 3 projects. The designations of the individual parts are retained in all figures. A stepping motor 4 having a stator 6, a rotor axle 5 and a motor output gear wheel 7, to be fastened thereto, can be fastened to a holding plate 8. Likewise, a gearing 9, which has a gear shaft 1 having a first gear wheel 11 and a second gear wheel 12 fastened thereto, can be attached to the holding plate 8. The gear shaft is mounted between the stepping motor 4 and a counter-bearing plate 13. Drive electronics 19 are additionally attached to the holding plate 8 or even integrated into the holding plate 8 (the holding plate 8 and the drive electronics 19 form a mechanical unit), specifically such that subsequently electrical connections 20 are arranged on the outside of an overall housing 16 that is produced following the assembling of the holding plate 8 and a basic housing 15. As far as the connections 20 are arranged on the outside of the basic housing 15, a suitable connection, not represented separately here, must be made between the drive electronics 19 and connections 20, this being achievable by usual techniques such as cables with plug-in connections, soldered connections and the like, prior to assembling. Clearly, in the case of data lines, a connection that can be operated with as little interference as possible should be provided.

[0035] The holding plate 8, together with the stepping motor 4, the gearing 9 and the drive electronics 19, forms a very compact drive unit 14, which can be inserted into the barrel-shaped basic housing 15, the holding plate 8 forming a kind of flat cover that realizes a level joint 23 with the basic housing 15. During assembling, a joint sealing 24, not represented, can be introduced into this level joint 23, for the purpose of tightly sealing the overall housing 16, composed of the basic housing 15 and the holding plate 8. The basic housing 15 has a lateral opening 17, through which the gear rack 3 of the device 2 to be driven is inserted into the inside of the overall housing 16 and there brought into engagement with the second gear wheel 12 of the gearing 9. A centering device 18 on the basic housing 15, together with a corresponding counter-piece on the device 2 to be driven, ensures exact positioning of the gear rack 3 which, in the present exemplary embodiment, is not carried or guided in the overall housing 16, but only in the device 2 to be driven. It is, however, also possible to provide, in the overall housing 16, a counter-bearing on the side of the gear rack 3 that is opposite the second gear wheel 12.

[0036] FIG. 2, in a partially sectional and schematic view, shows the action of the drive unit 14 of the linear drive 1 according to the present disclosure in combination with the device 2 to be driven, in an assembled state. The electrical connections 20 attached to the outside of the overall housing 16 only have to have a voltage supply 21 and a connection 22 for a bus system for controlling the drive electronics 19 arranged in the overall housing 16.

[0037] FIG. 3 again illustrates the structure and the size ratios of the drive unit 14 in the assembled state. It can be seen that, following the installation of the stepping motor 4, the stator 6 of which has an external diameter D (or, in the case of, for instance, a square cross section, a corresponding cross-sectional width) that is significantly less than the width B or the length L of the approximately square holding plate 8, next to the stepping motor 4 and the gearing 9 sufficient space still remains for the drive electronics 19. The axial length of the stator is approximately twice as great as its diameter, or cross-sectional width. As absolute dimensions in the exemplary embodiment shown, there is a cross-sectional width of, for instance, 26 mm and a stator length of, for instance, 55 mm.

[0038] FIG. 4, like FIG. 1, shows the parts that belong to a drive unit according to the present disclosure.

[0039] FIG. 5 shows a lateral view of the relatively flat structural form of the entire linear drive 1 not yet illustrated in the preceding figures. It can be seen here that the basic housing 15 is in the shape of a barrel, and has a height H. The drive unit 14 which, as it were, is suspended on the holding plate 8, can be inserted into the barrel-shaped basic housing 15 from above, such that an overall housing 16 is produced and a level joint 23 is formed between the two housing parts 8, 15. The diameter D of the stator 6 of the stepping motor 4 is less than the height H of the overall housing 16 but, owing to a relatively long axial length, the stepping motor 4 in combination with the gearing 9, can nevertheless apply the toques required of such a linear drive 1. FIG. 5 also illustrates the difference in relation to other concepts in the prior art, in which stepping motors are fitted into flat housings. In the case of the present disclosure, the rotor axle 5 of the stepping motor 4 does not lie in the direction of least extent, namely the height H of the overall housing 16, but perpendicularly thereto. Moreover, the motor is not first fitted into a barrel-shaped housing and brought into engagement with a gear rack before the whole is closed by a cover. In the case of the present disclosure, a gear rack 3 can be inserted through a lateral opening 17 after the overall housing 16 has been closed. The gear rack 3 is brought into a correct position by a centering means 18. A flange 25 on the overall housing 16 allows the fastening of a device 2 to be driven.

[0040] FIG. 6 likewise shows in a lateral, partially sectional view, but from a different direction from that of FIG. 5, a linear drive 1 according to the present disclosure in an assembled state and with an indicated flange-mounted device 2 to be driven, such that the gear rack 3 thereof is in engagement with the second gear wheel 12 of the gearing 9. It becomes evident that the lateral arrangement of the stepping motor 4 not only creates space for drive electronics 19 on the holding plate 8, but also a large amount of space for the movement of the gear rack 3, such that a relatively large drive path can be realized. Also evident are the barrel-shaped form of the basic housing 15 and the level joint 23 between the basic housing 15 and the holding plate 8, with an indicated joint sealing 24. The type of the sealing, however, is of secondary importance, and may depend on the ambient and temperature conditions to be dealt with.

[0041] FIG. 7, in the same view as in FIG. 6, shows a further exemplary embodiment of the present disclosure, in which the gear rack 3 is provided with a joint 28, such as a ball joint, and guided by a counter-bearing 27 and pressed against the second gear wheel 12 of the gearing 9. This embodiment facilitates the assembling of the linear drive 1 according to the present disclosure with a device 2 to be driven, and allows certain tolerances in the alignment of these two parts, without limiting the precision of the guiding.

[0042] The linear drive according to the present disclosure may be very compact, in particular having dimensions of, for example, a height H of approximately 48 mm, and a length L and a width B each of approximately 120 mm. The linear drive according to the present disclosure is consequently particularly suitable for driving hydraulic valves that are disposed next to each other in a row. The drive is easy to exchange, even on an inner hydraulic valve of a row, and in the case of integrated drive electronics the amount of electrical supply leads can be kept small. However, the linear drive according to the present disclosure can also be used without difficulty for driving other devices, insofar as the latter have their own suitable built-in gear rack.

[0043] While various embodiments of the present disclosure have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the present disclosure, as defined by the appended claims.