WO2012045387A1

WO2012045387A1 - Electrohydraulic unit

Info

Publication number: WO2012045387A1
Application number: PCT/EP2011/004563
Authority: WO
Inventors: Thomas Gellner
Original assignee: Robert Bosch Gmbh
Priority date: 2010-10-09
Filing date: 2011-09-10
Publication date: 2012-04-12
Also published as: DE102010048111B4; DE102010048111A1; TW201241314A; TWI611102B

Abstract

The invention relates to an electrohydraulic unit having a hydraulic pump driven by an electric motor and a determination unit by means of which an actual value of a rotational speed or a stroke rate of the hydraulic pump can be determined, and having a closed-loop control unit by means of which the electric motor can be subjected to closed loop control on the basis of the actual value. According to the invention the determination unit is associated with the hydraulic pump.

Description

Electrohydraulic unit

description

The invention relates to an electro-hydraulic unit according to the preamble of claim 1.

Such an electro-hydraulic unit has an electric motor, via which a hydraulic pump is driven, and has the task of supplying a hydraulic consumer with pressure medium. As a rule, this must be done against a variable or load-influenced load. The hydraulic pump is coupled to a shaft of the electric motor. The pumped by the hydraulic pump pressure medium flow can be adjusted depending on the design of the hydraulic pump on their rotation or their stroke rate or stroke frequency. For a rotary working hydraulic pump, for example an axial piston pump, this is the speed of the drive shaft. For a translationally operating hydraulic pump, for example a translatory and cyclically operating hydraulic cylinder, it is the stroke rate of its piston. The speed or the number of strokes result from the speed of the electric motor. The

Electro-hydraulic unit is often referred to as a variable-speed pump unit (dvP). Particularly simple designed electro-hydraulic units have a

Constant pump, so that the pressure medium flow is adjusted substantially via the speed of the hydraulic pump or the electric motor.

To the dependent of the speed of the hydraulic pump pressure medium flow even with variable load or the occurrence of disturbances on the electric motor

adjust as needed, have conventional electro-hydraulic units, a determination unit for determining the speed of the electric motor and a l Control unit for controlling its speed in a closed-loop arrangement. From the determined speed of the electric motor is closed to the speed of the hydraulic pump, whose determination is carried out in this way indirectly. In conventional electro-hydraulic units, the determination unit is arranged on or in the electric motor.

The disadvantage of this is that the determination unit is arranged with high device, in particular shielding technical effort on or in the electric motor.

In contrast, the invention is based on the object to provide a more cost-effective determination of the pressure medium flow influencing speed.

This object is achieved by an electro-hydraulic unit having the features of patent claims 1 or 13.

Advantageous developments of the invention are described in the dependent claims 2 to 12. An electro-hydraulic unit, in particular for supplying a hydraulic

Consumer with a pressure medium or a pressure medium flow, has an electric motor, via which a hydraulic pump is driven. Furthermore, the electro-hydraulic unit has a determination unit, via which an actual value of a rotational speed or a stroke rate of the hydraulic pump can be determined. About a control unit of the electro-hydraulic unit, the electric motor in dependence of the actual value can be regulated. According to the invention

Assigned determination unit of the hydraulic pump, so that the speed can be determined directly on the hydraulic pump instead of conventional manner on the electric motor.

Compared to a conventional assignment of the determination unit to

Electric motor, the inventive assignment to the hydraulic pump has the advantage that the determination unit comparatively far from an electric or

Magnetic field of the electric motor is arranged and thus a shielding of the determination unit against the interfering fields is less complex or even obsolete. As a result, the electric motor is simpler, ie can be formed without a determination unit that a cheap standard electric motor can be used. Likewise, a standard control unit can be used. Electrohydraulic units according to the invention are therefore comparatively inexpensive.

The electric-hydraulic unit according to the invention is thus designed as a variable-speed pump unit (dvP) in which a regulation of the pressure medium flow in the

Essentially about the regulation of the electric motor takes place. The inventive

Assigning the determination unit to the hydraulic pump causes a Aufregelzeit the hydraulic pump is shortened until a control deviation of the pressure medium flow, so that the pressure medium flow rate of the hydraulic pump is highly dynamically controlled.

The speed or stroke rate can be determined for rotary hydraulic pumps in "revolutions per unit time", for translationally operating hydraulic pumps in "strokes per unit time". A control of the electric motor via a closed-loop, the control unit adjusts the actual value of the rotation or stroke rate with a setpoint.

In addition, in addition to the actual value of the number of revolutions or strokes, the control unit can receive further actual values of other process variables of the electrohydraulic unit or of the supplied hydraulic consumer, such as a position of an actuator or hydraulic cylinder, a pressure or a pressure medium flow, in order to obtain the setpoint value of the rotary or stroke number Determine stroke rate of the hydraulic pump. The desired value can additionally or alternatively also be determined by a secondary or higher-order control unit. In addition or as an alternative, the setpoint can be selected by an operator via a

Manual interface of the control unit be manually specified.

In a preferred embodiment, the determination unit has a

Magnetic field sensor and an at least partially magnetizable encoder, so that the number of revolutions or strokes can be determined by utilizing a "Hall effect." It is particularly advantageous that the rotational or stroke rate can be determined without contact via such a sensor.

In a preferred embodiment, the magnetic field sensor is fixed to the housing on or in a housing of the hydraulic pump while maintaining a proper distance and a proper orientation relative to the encoder. Especially is advantageous if the sensor and the encoder are at least partially disposed within the housing, so that relevant for the determination of the sections

Determination unit on the housing against an electric or magnetic field - for example, the electric motor - are shielded.

The encoder preferably has a non-magnetizable section or a

Recess on, so that when a relative movement of the encoder to the sensor

Magnetic field of the determination unit is changed at least once. In a preferred embodiment, the encoder is designed as a gear and connected to a rotating part of the hydraulic pump, so that the speed can be determined via the sensor. The type of rotating part depends on a type of pump and may for example be a shaft, a cylinder drum, an impeller or an internal or external gear or an associated part.

In an alternative preferred embodiment, the encoder may be formed as a rack and is connected to an approximately linearly moving part of the hydraulic pump, so that the stroke rate can be determined via the sensor. The type of linearly moving part depends on the type of pump and can, for example, a piston or a

Be piston rod or an associated part.

Preferably, the gear or the rack has a modulus of greater than 0.3 in order to allow sufficient measurement accuracy. In a particularly simple refinement of the encoder is designed as a stamped sheet and thus made very cheap.

In a particularly preferred and inexpensive development has the

Determining unit a DSM speed sensor of the applicant, due to its robustness and degree of protection especially for use within the housing of the

Hydraulic pump is suitable. It is also advantageous that a rotational or lifting direction and a standstill can be determined via this sensor. In a preferred development, a speed of the electric motor can be regulated via the control unit.

In a particularly simple and inexpensive development, the hydraulic pump is a fixed displacement pump, so that the pressure medium flow of the hydraulic pump via the rotational speed of the electric motor and thus the hydraulic pump is set. For such

electrohydraulic unit, the inventive determination of the speed of the hydraulic pump is particularly advantageous. If the hydraulic pump is coupled to the electric motor via a gear, it is possible to lower or translate a rotational speed of the electric motor.

An electro-hydraulic unit according to the invention has a hydraulic pump driven by an electric motor, in particular a constant-displacement pump, and a

Determination unit, which has a Hall sensor with a sensor. About the

Determination unit is an actual value of a speed of the hydraulic pump determinable. Furthermore, the electro-hydraulic unit has a control unit via the one speed of

Electric motor in response to the actual value of the speed of the hydraulic pump and a setpoint is adjustable. The Hall sensor and the encoder are arranged on a part associated with the hydraulic pump.

In the following, a prior art and an embodiment of an electro-hydraulic unit will be explained in more detail with reference to two schematic drawings. Show it:

Figure 1 shows a conventional electro-hydraulic unit with a determination unit within a housing of an electric motor; and

Figure 2 shows an embodiment of an electro-hydraulic unit according to the invention with a determination unit within a housing of the hydraulic pump.

Figure 1 shows a conventional electro-hydraulic unit 1 with a

Determination unit 16 within a housing 18 of an electric motor 6. The electro-hydraulic unit 1 has a drive controller 2 which is connected via a signal line 4 to the electric motor 6. The electric motor 6 is coupled via a shaft 8 with a hydraulic pump 10. The hydraulic pump 10 is connected to a suction line 12, via which a pressure medium at a low pressure can be sucked. Furthermore, the hydraulic pump 10 is connected to a pressure line 14 via which the pressure medium to a hydraulic consumer (not shown) against a load or a

Load pressure can be conveyed.

On the electric motor 6 is via the determination unit 16, a speed of the

Electric motor 6 determinable. The determination unit 16 is arranged within the housing 18 of the electric motor 6 and carefully shielded from an electric and magnetic field of the electric motor 6.

To form a "closed-loop" or a control loop, the

Determination unit 16 via a signal line 20 connected to the drive controller 2. Via the signal line 20, the specific actual value of the rotational speed is transferred to the drive controller 2. In the drive control unit 2, an adjustment of the actual value takes place with a desired value of the rotational speed and via control parameters a determination of a manipulated variable for adaptation of a drive power of the electric motor 6 takes place.

FIG. 2 shows an electrohydraulic unit 101 according to the invention with a housing 18 arranged inside a constant-axial piston pump 10

Determination unit 1 16. The electro-hydraulic unit 101 has a drive controller 102, which has a

Signal line 104 is connected to an asynchronous electric motor 06. This is non-rotatably coupled to the constant-axial piston pump 110 via a drive shaft 108. The constant-axial piston pump 10 is connected to a suction line 112, via which a pressure medium at a low pressure can be sucked. Furthermore, the constant-axial piston pump 1 10 is connected to a pressure line 1 14, via which the pressure medium to a hydraulic consumer (not shown) against a load or a load pressure can be conveyed.

Within the housing 1 18 of the constant-axial piston pump 1 10 is a

Determination unit 1 16 is arranged, which works on the basis of the "Hall" effect Hall sensor 1 16a and a Hall sensor 1 16b. The Hall sensor 1 16b is designed as a DSM speed sensor of the series 10 of the applicant.

The Hall sender 1 16a is formed as a ferromagnetic gear with 48 teeth with a module of 1, which is stamped from a 6mm thick St37 sheet. Hall sensor 1 16b has IP69K protection so that it is protected against dust, access by wire and high-pressure water. Its temperature resistance is given in a temperature interval between -40 ° C and 150 ° C. The Hall sensor 1 16b is attached via a clip (not shown) in a simple manner to the housing 1 18 of the constant-axial piston pump 10 and arranged relative to the Hall generator 116a so that a longitudinal axis of the Hall sensor 116b with a maximum deviation of 2 ° normal on a Partial circle of the gear cutting circular cylindrical surface is arranged.

Trained as a DSM speed sensor determination unit 1 16 has the following self-diagnostic functions: a standstill detection and detection of a wrong arrangement of the Hall sensor 1 16b relative to the Hall sender 1 16a.

Further operating parameters which are relevant for the function of the determination unit 16, in particular with regard to the arrangement of the Hall sensor 16b relative to the Hall sensor 16a, can be taken from the Applicant's data sheet RD95132.

Via the determination unit 116, a rotational speed of the constant-axial piston pump 110 can be determined. The determination unit 1 16 is shielded via the housing 1 18 of the constant-axial piston 110 against an electrical and magnetic field of the electric motor 106.

The determination unit 1 16 is connected to the transfer of the specific actual value of the speed of the constant-axial piston pump 1 10 to the drive controller 102 via a signal line 120 with this. In the drive controller 102, the adjustment of the actual value with a nominal value of the rotational speed and control parameter via a determination of a manipulated variable for adapting a drive power of the asynchronous electric motor 106th

The setpoint value can be transferred via a manual operator interface (not shown) by an operator via a signal line 122 to the control unit 102 be and / or by a secondary or higher-level control unit (not shown) in dependence on actual values of process and / or operating parameters of the

electro-hydraulic unit or the hydraulic consumer (not shown) via a signal line 124 passed.

The design of the hydraulic pump of the electro-hydraulic unit is not limited to the shown constant-axial piston pump 1 10 in swash plate design. It can be used as a rotary hydraulic pump, for example as an external or internal gear,

Toothed ring, screw, vane or radial piston pump, or be designed as a translatory and cyclically operating hydraulic cylinder.

The hydraulic pump may be adjustable or constant.

Disclosed is an electro-hydraulic unit with a driven by an electric motor hydraulic pump and with a determination unit, via which an actual value of a speed or a stroke rate of the hydraulic pump can be determined, and with a control unit via which the electric motor in dependence of the actual value can be controlled. According to the invention, the determination unit is assigned to the hydraulic pump.

LIST OF REFERENCES

1 electrohydraulic unit

2 drive controller

4 signal line

6 electric motor

8 wave

10 hydraulic pump

12 suction line

14 pressure line

16 Determination unit

18 housing

20 signal line

101 Electrohydraulic unit

102 drive controller

104 signal line

106 asynchronous electric motor

108 drive shaft

1 10 Constant axial piston pump

1 12 suction line

1 4 pressure line

1 16 Determination unit

1 18 housing

116a Hall transmitter

1 16b Hall sensor

120 signal line

122 signal line

124 signal line

Claims

Electrohydraulic unit with a by a electric motor (106) driven hydraulic pump (1 10), and with a determination unit (1 16) via which an actual value of a speed or a stroke rate of the hydraulic pump (110) can be determined, and with a control unit (102) via in that the electric motor (106) can be regulated as a function of the actual value, characterized in that the determination unit (1 16) is associated with the hydraulic pump (110).

Electrohydraulic unit according to claim 1, wherein the determination unit (116) has a magnetic field sensor (1 16b) and an at least partially magnetizable encoder (1 16a).

Electrohydraulic unit according to claim 2, wherein the magnetic field sensor (116b) is fixed to the housing at or in the hydraulic pump (110).

Electrohydraulic unit according to claim 2, wherein the encoder (1 16a) has a non-magnetizable portion or a recess.

Electrohydraulic unit according to claim 2, wherein the encoder (1 6a) is designed as a gear and with a rotating part (108) of the hydraulic pump (1 10) is connected.

Electrohydraulic unit according to claim 2, wherein the encoder (1 16a) is designed as a rack and is connected to a substantially linearly moving part of the hydraulic pump (1 10).

Electrohydraulic unit according to claim 5 or 6, wherein the gear or the rack has a modulus greater than 0.3.

Electrohydraulic unit according to claim 2, wherein the encoder (116a) is formed as a stamped sheet metal. Electrohydraulic unit according to claim 1, wherein the determining unit (1 16) comprises a DSM speed sensor (1 16b).

Electrohydraulic unit according to claim 1, wherein a speed of the electric motor (106) is controllable via the control unit (102).

Electrohydraulic unit according to claim 1, wherein the hydraulic pump (1 10) is a fixed displacement pump.

Electrohydraulic unit according to claim 1, wherein the hydraulic pump (1 10) is coupled via a transmission with the electric motor (106).

Electrohydraulic unit with a hydraulic pump (110) driven by an electric motor (106), and with a determination unit (16) having a Hall sensor (116b) with an encoder (116a), an actual value being determined via the determination unit (116) Speed of the hydraulic pump (1 10) can be determined, and with a control unit (102), via which a rotational speed of the electric motor (106) in dependence of the actual value and a desired value can be regulated, characterized in that the encoder (1 16a) and the Hall sensor (116b) are arranged on a part of the hydraulic pump (1 10).