WO1999062754A1

WO1999062754A1 - Hydraulic steering arrangement

Info

Publication number: WO1999062754A1
Application number: PCT/DK1999/000292
Authority: WO
Inventors: Tage Christiansen; Nils E. Sevelsted
Original assignee: Danfoss Fluid Power A/S
Priority date: 1998-06-04
Filing date: 1999-06-02
Publication date: 1999-12-09
Also published as: DE19824926A1; DE19824926C2; AU3811499A

Abstract

In a hydraulic steering arrangement with a housing, an inner control slide (4) and an outer control slide (3) are arranged to be mutually rotatable in a bore in the housing. A measuring motor (6) is connected with the housing via an intermediary plate (16). One end of the inner control slide (4) is connectable with the steering shaft of a steering handwheel. The front side of the other end is adjacent to the intermediary plate (16). A tooth row (18) arranged concentrically to the steering shaft is rotatable in dependence of the rotation of the steering shaft, the rotation of the tooth row being converted to an electrical signal by a sensor (21). The tooth row (18) is incorporated in the front side of the inner control slide (4), and the sensor (21) is arranged in the intermediary plate (16). With this construction of the tooth row (18) and arrangement of the sensor (21), the traditional construction of the steering arrangement can to a great extent remain unchanged. Thus, separate production and mounting of the tooth row (18) can be avoided.

Description

Hydraulic steering arrangement

The invention concerns a hydraulic steering arrangement with a housing having a bore, in which an inner control slide and an outer control slide are arranged to be mutually rotatable, with a measuring motor connected with the housing via an intermediary plate, one end of the inner control slide being connectable with the steering shaft of a steering handwheel and the front side of the other end being adjacent to the intermediary plate, with a tooth row arranged to be concentric to the steering shaft and rotatable in dependence of the rotation to the steering shaft, and with a sensor converting the rotation of the tooth row into an electrical signal.

In a hydraulic steering arrangement, known per se from DE 39 30 147 C2 or DE 43 42 933 C2, it is wanted to trigger the pressure build-up in the system in dependence of a rotation of the steering handwheel, an electric motor being turned on by a rotation of the steering handwheel, which motor drives a hydraulic pump causing the pressure build-up.

For this purpose, it has been proposed in the bulletin Research Disclosure December 1997/941 to provide the steering shaft of the steering handwheel in such a hydraulic steering arrangement with a tooth row in the shape of separate toothed rim, whose rotation is detected by a sensor producing an electrical signal for the operation of the motor driving the hydraulic pump. However, a separate toothed rim is expensive with regard to material and mounting.

It is the task of the invention to provide a hydraulic steering arrangement as described in the introduction requiring less expenses for the tooth row. According to the invention, this task is solved in that the tooth row is provided in the front side of the inner slide and the sensor is arranged in the intermediary plate.

With this solution additional material is not required for the production of the tooth row, and a separate mounting of the tooth row is avoided.

Preferably, the sensor is arranged in a bore in the intermediary plate.

In the following, the invention is described in detail by means of a preferred embodiment example in connection with the drawings, showing:

Fig. 1: a sectional view of a hydraulic steering arrangement according to the invention, shown schematically

Fig. 2: the section A in Fig. 1 in an enlarged scale

Fig. 1 shows a schematic view of a steering arrangement with a housing 2 having a bore 2. In the bore 2 an outer control slide 3 and inside this an inner control slide 4 are arranged to be rotatable. A cardan shaft 5 connects a measuring motor 6 with the outer control slide 3. The inner slide 4 is connectable with a steering shaft 8 of a steering handwheel 9 via a coupling 7. Here, the coupling 7 is shown as a multi-spline coupling, into which the steering shaft can be inserted.

The outer control slide 3 and the inner control slide 4 are connected with each other via flat springs 10, permit- ting a limited mutual rotation of the two control slides

3, 4.

The measuring motor is a gear motor having an outer toothed rim 11 and an inner gear wheel 12, having displacement chambers 13 arranged between them, the whole device being closed by a cover 14. The housing 3 and the measuring motor 6 are connected with each other via an intermediary plate 16 by means of screws, of which only one screw 15 is shown, the front side of the end of the control slide 4 not connected with the steering shaft 8 bearing on the intermediary plate 16. A spacer ring 17 with a central hole keeps the cardan shaft 5 in the correct axial position.

The front side of the inner control slide 4 bearing on the intermediary plate 16 is provided with a tooth row 18, incorporated in the front side of the inner control slide

4. The side of the intermediary plate 16 facing the inner control slide 4 is provided with a vertical bore 19 connected with a transversal bore 20 leading to the outside. In the bore 19 a sensor 21 is arranged opposite the tooth row 18, which sensor produces an electrical impulse on each passing of a tooth of the tooth row 18, the impulse being supplied to a smoothing arrangement via an electrical cable 22 led out through the bores 19, 20, the smoothing arrangement converting the electrical impulses into a smoothed electrical signal turning on an electrical motor for as long as it takes, that is, as long as the teeth of the tooth row 18 move past the sensor 21. The electric motor drives a hydraulic pump building up the hydraulic pressure in the steering arrangement. As soon as the steering handwheel 9 is turned in one direction or the other, the steering shaft 8 turns the inner control slide 4, and thus also the tooth row 18 concentric to the steering shaft, relative to the sensor 21, and the electric motor is turned on practically immediately, causing a pressure build-up in the system.

Otherwise, the mode of operation and the construction of the steering arrangement are known per se, for example from the German patent documents mentioned in the introduction, so that a detailed description in that respect can be omitted.

The tooth row 18 can be a closed gear rim or only part of such a gear rim. As it is incorporated in the front side of the inner control slide 4, costs for additional material and mounting of the tooth row 18 are saved. Further, the tooth row 18 can be made in a simple manner in already existing control slides, namely by means of a milling process. Also the production of the bores 19 and 20 and the arrangement of the sensor 21 in the intermediary plate 16 are easily performed, without appreciable influence on the traditional mode of operation and construction of the steering arrangement.

The sensor 21 can, for example, be a capacitive, inductive or optically working sensor.

Claims

Patent claims

1. Hydraulic steering arrangement with a with a housing (1), having a bore (2), in which an inner control slide (4) and an outer control slide (3) are arranged to be mutually rotatable, with a measuring motor (6) connected with the housing (1) via an intermediary plate (16), one end of the inner control slide (4) be- ing connectable with the steering shaft (8) of a steering handwheel (9) and the front side of the other end being adjacent to the intermediary plate (16), with a tooth row (18) arranged to be concentric to the steering shaft (8) and rotatable in dependence of the rotation of the steering shaft (8), and with a sensor (21) converting the rotation of the tooth row (18) into an electrical signal, characterised in that the tooth row (18) is provided in the front side of the inner slide (4) and the sensor (21) is arranged in the intermediary plate (16) .

2. Hydraulic steering arrangement according to claim 1, characterised in that the sensor (21) is arranged in a bore (19) in the intermediary plate (16) .