WO2010121686A1

WO2010121686A1 - Device for measuring a set swept volume

Info

Publication number: WO2010121686A1
Application number: PCT/EP2010/001514
Authority: WO
Inventors: Werner Hörmann; Markus Schmid
Original assignee: Robert Bosch Gmbh
Priority date: 2009-04-21
Filing date: 2010-03-11
Publication date: 2010-10-28
Also published as: EP2422088A1; DE102009018298A1; CN102405350A; CN102405350B; KR20120018119A; JP2012524209A

Abstract

The invention relates to a device for measuring a set swept volume of a hydrostatic piston machine (1). The device has an actuating element (4) for generating an actuating movement, and a sensor (6) for measuring a position of the actuating element (4). A signal indicating the position of the actuating element (4) is generated by the sensor (6). The actuating element (4) interacts with the sensor (6) via a transmission device (5). According to the invention, the transmission device (5) has a groove (11) which extends along a plane which is parallel to the movement direction of the actuating element (4). A longitudinal axis of the groove (11) encloses a non-zero angle a with a projection of the movement direction into the plane of the groove (11). To transmit the movement of the actuating element (4), a transmission element (10) engages into the groove (11).

Description

Device for detecting a set stroke volume

The invention relates to a device for detecting a set stroke volume of a hydrostatic piston engine.

From DE 101 19 236 Cl a hydrostatic piston machine in Schrägachsenbauweise is known. The axial piston machine is designed adjustable. For adjusting the inclination angle of the cylinder drum axis against the drive shaft axis, an adjusting device is provided with an actuating piston. The adjusting piston is displaceably guided in the direction of its actuating piston axis and connected to the cylinder drum for adjustment. In order to detect the set swivel angle of the axial piston, a sensor is provided. The sensor is designed as a rotation angle sensor. To detect the position of the actuating piston and thus ultimately the set displacement or displacement volume of the axial piston machine, a lever arm is arranged on the shaft of the sensor. While one end of the lever arm is rotatably connected to the shaft, the end facing away from it is inserted into a recess of the actuating piston. A linear displacement of the actuating piston thus causes a rotation of the lever arm about the shaft axis. An adaptation of the maximum control piston travel to the adjustment range of the rotation angle sensor via a suitable selection of the length of the lever. However, this can lead to a considerable increase in the total installation space of the axial piston machine in the case of long travel ranges.

In particular, it is disadvantageous that the sensor unit formed laterally on the housing has a relatively large distance from the actual actuator housing with increasing reduction. This makes it difficult Installation situation and the exposed position of the sensor leads to a considerable risk of damage.

It is therefore the object of the invention to provide a device for detecting a set stroke volume, in which an adaptation between the maximum movement of the actuating piston and the detection range of the sensor is possible, wherein a compact design is achieved.

The invention achieves the aforementioned object with the features of claim 1.

According to claim 1, the device for detecting a set stroke volume or associated with this pivot angle of a hydrostatic piston engine has an actuating element for generating an actuating movement and a sensor for detecting a position of the actuating element. The sensor generates a signal indicative of the position of the control element, the control element being connected to the sensor via a signal

Translation device cooperates. According to the invention, this translation device now has a groove. This groove extends along a plane lying parallel to the direction of movement of the actuating element. The longitudinal axis of the closes. Groove with a projection of the direction of movement of the actuating element in the plane of the groove a non-0 angle. In the groove engages a transmission element for transmitting a movement of the actuating element on an actuating element of the sensor.

By a suitable selection of the angle, which includes the longitudinal axis of the groove with the projection of the direction of motion in the plane parallel to the direction of movement, the transmission ratio is set. Without this, a distance between the actuator and the sensor must be increased, this can be done by adjusting the maximum adjustment movement to the detection range of the sensor. Leave it to realize a compact machine. By the intervention of a transmission element in the groove is further ensured that regardless of a direction of movement always a restoring force is exerted on the transmission element.

In the dependent claims advantageous developments of the device according to the invention are given.

In particular, it is advantageous to use the sensor as

Form rotational angle sensor, wherein in a rotatable actuating element of the rotation angle sensor, the transmission element is arranged eccentrically. The insertion of the transmission element into the groove of the transmission device thus leads due to the eccentric arrangement in the actuating element to a rotary motion and thus to an immediate control of the sensor.

Furthermore, it is advantageous to the groove in a

To bring in an articulation piston, which has a flattened portion at least at its end remote from the actuator. The groove is then arranged in the region of this flattening. The Anlenkkolben serves to transfer the position of the actuating piston on the Übertragungselemeht and so ultimately on the sensor. By different Anlenkkolben may optionally, without a redesign of the actual control element is required to make an adjustment, for example, to different sensors. This reduces the cost and facilitates the adaptation to different generations of aggregates. Only the translation device needs to be adjusted by changing the angle. The flattening also allows the piston is secured in a simple manner against twisting.

For this purpose, a guide surface is preferably formed corresponding to the flattening in the receiving housing of the adjusting device. Furthermore, it is preferred that the groove is introduced into a Anlenkkolben and this Anlenkkolben has on its the actuator facing side a spring bearing. By forming the spring bearing to the

Anlenkkolben is a separate fixation of the actuating piston or the actuating element on the Anlenkkolben not required. Due to the spring force, the actuating element facing side of the Anlenkkolben is always held in contact with an end face of the actuating element.

According to a further preferred embodiment, the connecting piston and the adjusting element are connected to each other secured against rotation. Such a rotation lock between the adjusting element and the connecting piston makes it possible, in particular, to use an anti-twist device, which is formed between the connecting piston and the housing, at the same time as a security against rotation for the actuating element. The adjusting element itself can therefore be designed, for example, as a rotationally symmetrical actuating piston, which simplifies the production and thus ultimately reduces the costs. The transmission element is preferably a ball stud. The ball-head-shaped end of the ball stud engages in the groove. Such a design of the ball stud and the guide on the ball-head side, the reliability is further increased because jamming in the groove is reliably avoided. In particular, play in the spherical head design component tolerances, as they inevitably arise in manufacturing plays a minor role. In addition, the positioning in the actuator is irrelevant.

Preferably, the device according to the invention is an integral part of a hydrostatic piston machine. As a result, the hydrostatic piston engine is already capable of the set To detect the swivel angle or the set stroke volume.

A preferred embodiment is shown in the drawing 5. and will be explained in more detail in the following description. Show it:

Fig.l a partial section through an axial piston machine in

Schrägachsenbauweise with the device according to the invention for detecting a pivot angle;

Fig. 2 is a partial section through a part of a

Adjusting device of the axial piston machine according to FIG. Ir 5

Fig. 3 is a section along the line III-III of Fig. 2;

4 is an enlarged view of the Anlenkkolbens0 to explain the position of the groove. and

Fig. 5 is a perspective view of the Anlenkkolbens. 5 The following comments are from one

Axial piston machine in bent-axis design. The illustrated examples relate to a double pump, it being self-explanatory that the invention can also be applied to other hydrostatic piston machines 0 in which an actuating movement must be translated for detection by a swivel angle sensor or a displacement sensor. In the following, only the term of the swivel angle will be used. In the axial piston machine 1, a cylinder drum 2 is arranged, in which a plurality of pistons are arranged in cylinder bores in a generally known manner. Due to the set angle of the cylinder drum axis relative to an input or output shaft axis, ie the pivot angle, the displacement changes. This can be used to change the set intake or displacement volume. For adjustment, a driver 3 is arranged in a control element in a housing-side mounting of the cylinder drum 2. The adjusting element is preferably designed as a control piston 4. The actuating piston 4 can be positioned between a first and second end position. This position corresponds to the set delivery volume in the case of an axial piston pump. To capture the

Position of the actuating piston 4 and thus the set pivot angle and thus the set stroke volume, a device according to the invention for detecting the pivot angle 5 is provided.

For better clarity, only a first overview of the device 5 is given in FIG. 1, the details of which are given below with reference to the other figures.

The device 5 comprises a sensor 6. The sensor 6 is designed in the illustrated embodiment as a rotary potentiometer. For detecting the pivoting angle, therefore, a linear movement or a set position of the actuating piston must be translated into an associated angular position of the shaft of the sensor 6.

In order to keep the actuating piston 4 at any time in a defined starting position, a spring 8 is provided, which acts on the actuating piston 4 in the direction of a first end position. In the illustrated embodiment, the spring 8 engages a Anlenkkolben 7, which is held by the spring 8 in contact with the actuating piston 4. By means of the Anlenkkolbens 7, a linear movement of the actuating piston 4 is transmitted to the actuating element 9. To avoid a relative rotation between the Anlenkkolben 7 and the actuating piston 4, a dowel pin is provided in the embodiment of FIG. The dowel pin engages in the mutually facing end faces of the actuating piston 4 and the Anlenkkolbens 7. The actuating element 9 is an intermediate piece, which is adapted to the respective mounting situation of the sensor 6 and transmits a movement of a transmission element 10 to the shaft of the sensor 6. The transmission element 10 is arranged eccentrically to the axis of the shaft of the sensor 6 as a rotational movement in the actuating element 9. The axis of the transmission element 10 and the actuating element 9 are parallel to one another and in particular are perpendicular to the direction of movement of the actuating piston 4.

In the Anlenkkolben 7 a groove 11 is introduced. The groove 11 extends along a plane which is parallel to the direction of movement of the actuating piston 4. The plane is also perpendicular to the axis of the shaft of the sensor 6. In the plane, the groove 11 is formed, wherein the groove extends obliquely to the direction of movement of the actuating piston 4. That a projection of the direction of movement or the

Stellkolbenachse on the plane includes with the longitudinal axis of the groove a 0 different angle. About the size of the angle can be doing the

Gear ratio of the transmission element 10 and the Anlenkkolben 7 having translation device set.

Fig. 2 shows once again the device for detecting the pivot angle in an enlarged view. It can be seen that the articulation piston 7 has a flattened region 12. Otherwise, the Anlenkkolben 7 is characterized by a sequence of circular cross sections, wherein at the end remote from the sensor 6, a spring bearing 13 is formed by a radial extension. At this spring bearing 13, the already explained with reference to FIG. 1 spring 8 is supported. The opposite end of the spring 8 is supported on the housing side. The groove 11 is inserted in the flattened region 12 of the Anlenkkolbens 7. The flattened region 12 forms an area on the articulation piston 7 which runs parallel to the plane of the groove 11 and in particular parallel to the direction of movement represented by the arrow in FIG. 2. The position of the plane is indicated in FIG. 2 by the dot-dash line 18. In the groove 11 engages the transmission element 10, which has a ball head 14 at its end engaging in the groove 11 end. The diameter of the ball head 14 is approximately equal to the width of the groove 11.

The sensor 6 is adjusted by rotating a shaft 15. For transmitting a movement of the transmission element 10 on the shaft 15, an actuating element 9 is provided. The actuating element 9 is rotatably connected to the shaft 15. In the illustrated embodiment, this is done via a flattened position on the shaft 15, wherein the shaft 15 engages in a corresponding geometry of the actuating element 9. The actuating element 9 is rotatably mounted in a housing of the sensor 6. Eccentric to the axis of rotation of the actuating element 9, which coincides with the axis of rotation of the shaft 15, is in the actuating element

9 on the, the Anlenkkolben 7 side facing the transmission element 10 is inserted. The transmission element

10 is rotationally symmetrical and its axis of symmetry runs parallel to the axis of rotation of the actuating element 9.

Due to the oblique arrangement of the groove 11 relative to the direction of movement of the actuating piston 4, a movement of the actuating piston 4 causes a lateral deflection of the transmission element 10 to the direction of movement. This lateral deflection leads to a rotation of the actuating element 9 about the axis of the shaft 15 of the sensor. Trained as a rotary potentiometer sensor then generates a signal which of the respective Position of the Anlenkkolbens 7 corresponds. Since the Anlenkkolben 7 with the actuating element, in the present example, the adjusting piston 4, is fixedly connected and thus follows an axial movement of the actuating piston 4, a signal corresponding to the position of the actuating element is output by the sensor 6. To transmit the signal to, for example, an electronic control unit, an electrical connection 17 is provided. In Fig. 3 is a section along the line III-III of Fig. 2 is shown. Matching elements are provided with identical reference numerals. Their full description is omitted to avoid repetition.

The section in FIG. 3 is perpendicular to the

Movement direction of the actuating piston 4 and thus also of the Anlenkkolbens 7. In Fig. 3 can be clearly seen that the flattened portion 12 forms on the Anlenkkolben 7 a surface which is parallel to the plane 18. Furthermore, it can be clearly seen that the axis 19 of the shaft 15 is perpendicular to the plane 18. As already explained, the width of the groove 11 coincides with the diameter of the ball-head-shaped end 14 of the transmission element 10. This creates a kind of forced operation, which avoids hysteresis effects compared to systems with one-sided installation.

4, the Anlenkkolben 7 is shown enlarged again. It can be seen that the longitudinal axis 20 of the groove 11 encloses an angle α with a projection of the direction of movement into the plane of the groove 11. The size of the angle a determines the transmission ratio of the translation device. It can also be seen that a recess 21 is formed on the end oriented in the direction of the spring bearing 3. The recess 21 facilitates insertion of the ball-shaped end of the transmission element 10. The Anlenkkolben 7 is in the Fig. 5 again shown in a perspective view.

It should be noted in particular that the proposed device for detecting a pivoting angle is not limited to the illustrated embodiment with a rotary potentiometer. In particular, sensors which require a linear movement to detect a position may also be provided. The direction of adjustment of such a sensor is then perpendicular to the

Movement direction of the actuating element, wherein here too the transmission element engages in the oblique groove 11. In particular, it is advantageous that neither a hysteresis occurs, nor the size of the entire arrangement depends on the set transmission ratio. In particular, the distance of a mounting surface on which the sensor 6 is arranged to the axis of the actuating piston 4 remains independent of the selected gear ratio.

The invention is not limited to the illustrated embodiment. In particular, individual features of the embodiment can be combined with each other in an advantageous manner.

Claims

claims

1. A device for detecting a set stroke volume of a hydrostatic piston engine (1) having an actuating element (4) for generating a

Adjusting movement and with a sensor (6) for detecting a position of the adjusting element (4) and for generating a signal characterizing the position, wherein the adjusting element (4) with the sensor (6) via a translation device (5) cooperates, characterized in that the translation device (5) has a groove (11) which extends along a plane (18) lying parallel to the direction of movement of the actuating element (4) and whose longitudinal axis (20) encloses a non-zero angle a with a projection of the direction of movement, and that in the groove (11) engages a transmission element (10) for transmitting a movement of the actuating element (4) on the sensor (6).

2. Apparatus according to claim 1, characterized in that for transmitting the movement in the transmission element (10) an actuating element (9) for transmitting the movement of the transmission element (10) to the sensor (6) is arranged eccentrically and the transmission element (10). is rotatable.

3. Apparatus according to claim 1 or 2, characterized in that the groove (11) in a Anlenkkolben (7) is introduced, which at least at its end facing away from the adjusting element (4) has a flattened portion (12) and that the groove (11) is arranged in the region of the flattening.

4. Device according to one of claims 1 to 3, characterized in that the groove (11) in a Anlenkkolben (7) is introduced, on whose, the adjusting element (4) facing side, a spring bearing (13) is formed.

5. Device according to one of claims 3 or 4, characterized in that the Anlenkkolben (7) and the adjusting element (4) are secured against rotation with each other.

6. Device according to one of claims 1 to 5, characterized in that the transmission element (10) is a ball stud.

7. Hydrostatic piston machine with a device for detecting a set pivoting angle, wherein the device is constructed according to one of claims 1 to 6.