HYDRAULIC TRANSPORT DEVICE AND ELECTROHYDRAULIC CONTROL MODULE

Abstract

A hydraulic transport device for transporting a hydraulic medium. The device includes at least one externally toothed gear pump that is driven by an electric motor, and a control device attached to the pump. A passive rotational speed detection element is arranged in the pump and interacts with an active rotational speed detection element that is arranged in the control device to detect the rotational speed of the pump shaft.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hydraulic transport device for transporting a hydraulic medium including at least one pump driven by an electric motor, and a control device. The invention also relates to an electrohydraulic control module with such a hydraulic transport device.

2. Description of the Related Art

Such transport devices are needed for hydraulic controls of vehicle transmissions, among other things. The pumps generate a volumetric flow for different tasks in the hydraulic control, such as actuating adjusting cylinders that require a high pressure and/or volumetric flow, or supplying coolant and/or lubricating medium to specific components. In some of these hydraulic controls, the pumps are driven by means of an electric motor.

To ensure that the hydraulic control functions optimally, control of the speed of the pump and/or the electric motor driving the pump is frequently required; consequently, it is necessary to detect the speed. It is known to detect the pump speed directly as the speed of the electric motor, that is, to sense the speed directly on or in the electric motor that drives the pump. The detected speed signals may be processed and sent via a signal line and plug-in connections to a control device where they are processed further. The signal lines can also serve as control or power supply lines.

The disadvantage of that type of speed sensing is that additional installation space is required for the electric motor, which can cause substantial problems depending on the installation space requirements. Another disadvantage is that a device for detecting speed that is mounted on the electric motor requires additional housing parts and hence additional costs. The same holds true for transmitting the signal and contacting the line between the electric motor and the control device.

A method is known from German patent application DE 100 06 320 A1 for electrically connecting an electric motor and electronic module including at least one speed sensor that can be positioned on a support body to detect the speed of the electric motor.

An object of the present invention is to provide an economical hydraulic transport device requiring little installation space.

SUMMARY OF THE INVENTION

The object is achieved by a hydraulic transport device for transporting a hydraulic medium including at least one pump that is driven by an electric motor and a control device. A passive detection element, especially a speed detection element, is arranged in the pump, which then interacts with an active detection element, especially a speed detection element, that is arranged in the control device. According to another aspect of the invention, the active speed detection element is integrated in the control device. That has the advantage that the transmission of the speed signal by a signal line between the electric motor and control device can be completely discarded. Furthermore, no additional housing parts are required for the speed sensors. Alternatively, or in addition to the speed detection elements, other detection elements can be used, such as torque detection elements. The electric motor is preferably a BLDG (brushless direct current) electric motor that is provided with detection elements, especially sensors.

A preferred exemplary embodiment of the hydraulic transport device is characterized in that the pump is arranged between the electric motor and the control device. The pump is preferably designed as a gear pump, especially as an externally toothed gear pump.

Another preferred exemplary embodiment of the hydraulic transport device is characterized in that the pump includes a pump shaft with an end to which the passive speed detection element is attached. The other end of the pump shaft can, for example, be coupled to the electric motor by means of a coupling.

Another preferred exemplary embodiment of the hydraulic transport device is characterized in that the passive speed detection element includes a magnet that is non-rotatably connected to the pump shaft. The magnet interacts electromagnetically with the active speed detection elements.

Another preferred exemplary embodiment of the hydraulic transport device is characterized in that the pump shaft is arranged coaxially to a motor shaft of the electric motor. The pump shaft and the motor shaft preferably have a common axis of rotation.

Another preferred exemplary embodiment of the hydraulic transport device is characterized in that the active speed detection element is arranged in a control housing body. The control housing body is part of a housing of the control device.

Another preferred exemplary embodiment of the hydraulic transport device is characterized in that the control housing body includes a relatively thin housing wall that is arranged between the active and the passive speed detection element. When the pump is operating, the speed signals are transmitted through the housing wall. The transmitted speed signals can be directly processed further in the control device.

Another preferred exemplary embodiment of the hydraulic transport device is characterized in that the pump is arranged in a control plate arrangement that is positioned between the control housing body and the electric motor. A plurality of pumps can also be arranged in the control plate arrangement. A plurality of control plates are preferably arranged between the control housing body and the electric motor. A pump is preferably arranged in each control plate. It is particularly preferable for two control plates with one pump each to be arranged between the control housing body and the electric motor.

Another preferred exemplary embodiment of the hydraulic transport device is characterized in that the electric motor is mounted on the control plate arrangement. The electric motor is, for example, screwed onto the control plate arrangement.

Another preferred embodiment of the hydraulic transport device is characterized in that at least one tooth of a pump gear is the passive detection element. The advantage of sensing, especially speed sensing, using the teeth of the pump gear is that no additional passive detection element is required.

The present invention also relates to an electrohydraulic control module with the above-described hydraulic transport device. The electrohydraulic control module preferably serves to control a vehicle transmission. The hydraulic transport device serves to generate a hydraulic volumetric flow for various tasks in the hydraulic control of the vehicle transmission. The functioning of the hydraulic control can be optimized by sensing rotational speed with the speed sensing elements arranged according to the invention.

BRIEF DESCRIPTION OF THE DRAWING

Additional advantages, features, and details of the invention are described in the following description in which an exemplary embodiment is described in detail with reference to the drawing. Shown in the drawing are:

FIG. 1 shows a cross section of an embodiment of an electrohydraulic control module with an embodiment of a hydraulic transport device according to the invention, and

FIG. 2 shows a cross section of an embodiment of a pump of the hydraulic transport device shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a cross section of an electrohydraulic control module 1 with a hydraulic transport device 4 according to an exemplary embodiment of the invention. The hydraulic transport device 4 includes a first pump 6 and a second pump 8. The two pumps 6, 8 are driven by an electric motor 10. The electric motor 10 is connected via an electric connecting cable 11, 12 to an electric power supply.

The control module 1, or the transport device 4, also includes a control device 15 with a control housing body 16. A control plate arrangement 20 including a first control plate 21 and a second control plate 22 is arranged between the control housing body 16 and the electric motor 10. An intermediate plate 23 is arranged between the two control plates 21, 22. Screws 25 are used to fasten the electric motor 10 to the top control plate 21, as shown in FIG. 1, of the control plate arrangement 20.

The first pump 6 is integrated in the first control plate 21. The second pump 8 is integrated in the second control plate 22. The two pumps 6, 8 are both designed as externally toothed gear pumps and are driven by a motor shaft 28 of the electric motor 10. The free end of the motor shaft 28 is coupled by means of a coupling 29 to a common pump shaft 30 of the two pumps 6, 8.

The coupling 29 non-rotatably connects the free end of the motor shaft 28 to a top end of the pump shaft 30, as shown in FIG. 1. The motor shaft 28 and the pump shaft 30 have a common rotational axis 33 that extends in the vertical direction in FIG. 1. A bottom end of the common pump shaft 30, as shown in FIG. 1, can be coupled by means of another coupling 34 to a pump gear 35 of the second pump 8. A pump gear of the first pump 6 is permanently non-rotatably connected to the common pump shaft 30.

The second pump 8 includes a pump cover 38 that seals the second control plate 22 open at the bottom in FIG. 1. Below the coupling 34 of the second pump 8, the pump cover 38 includes a recess in which a passive, freely rotatable speed detection element 41 is arranged. The passive speed detection element 41 is non-rotatably connected to the bottom end of the common pump shaft 30, as shown in FIG. 1.

The passive speed detection element 41 is preferably designed as a magnet and is fixedly connected to the bottom end of the common pump shaft 30, as shown in FIG. 1. The passive speed detection element 41 interacts electromagnetically with an active speed element 42 that is indicated in FIG. 1 by a rectangle. The active speed detection element 42 is separated from the passive speed detection element 41 by a relatively thin housing wall of the control housing body 16 and by another relatively thin housing wall of the pump cover 38.

The two housing walls are designed to be thin enough for the speed signals to be transmitted from the passive speed detection element 41 to the active speed detection element 42 while the hydraulic transport device 4 is operating. The two speed detection elements 41, 42 together constitute a speed sensor device 40 with which the rotational speed of the common pump shaft 30, and hence the rotational speed of the motor shaft 28 of the electric motor 10, can be easily detected. The detected speed signals can be directly processed further in the control device 15.

FIG. 2 shows that the pump gear 35 for the second pump 8 is designed as an external gear with external teeth 54. The pump gear 35 meshes with another externally toothed gear 55 to transport hydraulic medium as an externally toothed gear pump. By using a correspondingly suitable active speed detection element, the rotational speed of the common pump shaft 30 can also be sensed by means of the teeth of the pump gears 35, 55. In this case, the passive speed detection element is constituted by at least one tooth, or all of the teeth, of at least one external gear of the externally toothed gear pump 8. An additional external passive sensor detection element can then be eliminated.

Claims

1. A hydraulic transport device for transporting a hydraulic medium, said device comprising: at least one rotary hydraulic pump having a pump housing and that is driven by an electric motor; a control device connected with the pump housing and including a control device housing; a passive rotational speed detection element arranged within the pump housing; and an active rotational speed detection element arranged within the control device for interaction with the passive rotational speed detection element for detecting a rotational speed of the hydraulic pump.

2. The hydraulic transport device according to claim 1, wherein the pump is arranged between the electric motor and the control device.

3. The hydraulic transport device according to claim 1, wherein the pump includes a pump shaft having an end that is attached to the passive rotational speed detection element.

4. The hydraulic transport device according to claim 3, wherein the passive rotational speed detection element includes a magnet that is non-rotatably connected to the pump shaft.

5. The hydraulic transport device according to claim 3, wherein the pump shaft is coaxial with a motor shaft of the electric motor.

6. The hydraulic transport device according to claim 1, wherein the active rotational speed detection element is arranged in the control device housing.

7. The hydraulic transport device according to claim 6, wherein the control device housing includes a housing wall that is arranged between the active and the passive rotational speed detection elements.

8. The hydraulic transport device according to claim 6 wherein the pump is arranged against a control plate that is positioned between the control device housing and the electric motor.

9. The hydraulic transport device according to claim 8, wherein the electric motor is mounted on the control plate.

10. The hydraulic transport device according to claim 1, wherein at least one tooth of a pump gear having a plurality of teeth is the passive rotational speed detection element.

11. The hydraulic transport device according to claim 7, wherein the control device housing wall has a thickness that allows the passage therethrough of magnetic flux between the active and passive rotational speed elements.