DK147950B - ROTATION STAMP MACHINE FOR LIQUIDS - Google Patents

Description

U7950

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a rotary piston machine for liquids having a gear wheel and a gear ring, between which are displacement chambers, the gear wheel engaging with an articulated shaft and on which both sides of the tooth elements have one walls, one of which has an opening in the middle part. for the articulation of the articulated shaft while the other is closed in the corresponding area.

This kind of machinery is used as motors, pumps or flow meters. They are used as a driving force for vehicles and machines, in hydrostatic control units and in many other areas.

In a known rotary piston machine of the kind described in the preamble (DE-PS 19 06 445), the rotating and rotating sprocket over a link shaft is connected to a swivel slider.

The tooth ring is stationary. A bore in the housing accommodates the swivel slide and together with it forms a guide-swivel slide assembly. Control apertures in the swivel slide and in the bore alternate together to provide a functional connection of the displacement cells on the pressure side and on the low pressure side between cogs and gears with a pressure and low pressure connection on the machine. The cogwheel has parallel side surfaces, which are close to the end walls.

In such a rotary piston machine, the distance between the two end walls must be chosen so that the gear can be turned without any major frictional loss. This causes a gap between the cogs and adjacent end walls over which there is a leakage loss. In addition, the opening in the end wall is relatively large, since the shaft of the articulated shaft must have a definite cross-section for the transmission of the desired power, and the aperture must be correspondingly larger for the circular movement of the articulated shaft. However, this means that - when a permissible size of the leakage loss is not to be exceeded - the diameter of the gears must be chosen so large that the length of the sealing gap 10 on the side of the opening does not become too small, resulting in a correspondingly large tooth ring and contravene the requirements of the designer about that he should build as small machines as possible. However, a large loss of leakage leads to a larger slip. This is particularly annoying to note with 15 rotary piston machines for control units, as the steering wheel's predetermined setting does not transfer to the wheels proportionally, and the wheels must be constantly re-adjusted, even at straight-out with side loading. At given radial dimensions of the machine, these leakage losses are so much more troublesome, the smaller the width of the gear, since the leakage losses represent a higher percentage of the total quantity.

Furthermore, it is known (DE-OS 19 56 528) to provide each of the two gears which rotate about predetermined axes in a gear pump with a ring groove on both sides and to insert a sealing ring into the ring groove. Also known is a compressor assembly (CH-PS 404 067), in which there are two rotating pistons with internal engagement and eccentrically arranged axes, of which the cog on the inner circumference carries a resilient slide on one side. By means of the sliding, it is to be achieved that the gear with the opposite side is pressed against a cover containing the inlet and outlet openings.

Furthermore, there is known a rotary piston machine (DS-PS 3 775 031), in which the sprocket on both sides of the tooth flanks 147950 3 has recesses which serve as auxiliary channels and together with the internal toothing of the tooth ring serves as a secondary part of a conventional control swivel device to make a more precise operation of this control swivel slide device 5 is possible by operably connecting the displacement cells on the printing side and on the low pressure side with a pressure and low pressure connection on the machine. Such indentations on the tooth flanks are also known by a rotary piston machine (DE-OS 22 40 632) in which the internal sprocket within the teeth has indentations arranged for the fluid supply and discharge.

SUMMARY OF THE INVENTION It is an object of the invention to provide a rotary piston machine of the kind described in the introduction, in which the leakage losses can be kept small while maintaining the small radial dimensions and a sufficiently small friction.

The task according to the invention is solved according to the characteristics of claim 1.

By using the sealing ring, the leakage oil flow is virtually completely prevented on one side of the gear.

20 Thus, the goal of reducing the leakage losses has been achieved.

This seal cannot be made on the opposite side, as the sealing ring that would collide with the joint shaft required for the passage. However, this one-sided seal causes the pinion to be pressed against the apertured end wall with considerable force. Namely, on the sealed side, the full working pressure acts in the pressure region, while the leakage oil flow on the non-sealed side causes a pressure drop along the side, which leads to a correspondingly reduced axial counter-force. The friction losses would be equivalent to 30 large. This disadvantage caused by the one-sided seal can be avoided by the formation of pressure compensation surfaces which are opposite the sealing region and provide the gear with pressure compensation surfaces which are in recesses of the gear and associated with the displacement chambers. Therefore, it becomes possible to compensate for the large axial force caused by the one-sided seal so that it constantly corresponds to the pressure on the opposite side in the sealing region.

It is also possible that the sealing ring may be bifurcated and consist of an elastic ring disposed in the groove and a metallic sealing ring pressed against the corresponding work space end wall of the elastic ring.

The invention is explained in more detail below by means of an exemplary embodiment shown in the drawing, which shows in FIG. 1 is a longitudinal section through a rotary piston machine according to the invention; FIG. 2 is a right-hand view of cogs and gears; FIG. 3 is a plan view of the cogwheel from the opposite side; and FIG. 4 shows a varied shape of the sealing ring in section.

The machine of FIG. 1 has a sprocket 1 and a cooperating gear ring 2. These parts are covered on one side by a first end wall 3 formed by a lid and on the other side by a second end wall 4 formed by a between plate. End wall 3, tooth ring 2 and end wall 4 are connected to each other by means of screws 5 and to a housing 6. Between gears 1, tooth ring 2 and end walls 3 and 4, displacement chambers 7 are formed. Connection channels 8 are provided in the housing. each connecting a guide opening 9 in the inner circumference 10 of the housing 6, forming part of a guide swivel slider, with channels 11 in the end wall 4, which in turn are connected to the displacement chambers 7. In addition, connection plugs are arranged in the housing. 12, which also over channels 13 or 14 leads to inner circumferential wall 10, but is displaced axially with respect to the guide opening 9. At the free end of the housing, a closing plate 16 is provided by screws 15.

5 In a slide bearing 18, a main shaft 20 is mounted radially and between a bearing disk 19 and one of the plate 16, a main shaft 17. A joint shaft 21 engages a toothed head 22 in a tooth 23 of the main shaft and with another toothed head 24 in a tooth 25, which is arranged in a centric breakthrough 26 of the sprocket 1. The shaft of the articulated shaft 21 is passed through an opening 27 in the end wall 4.

The main shaft 17 is designed as a swivel valve 28 which has two annular grooves 29 and 30 which are connected to the connecting ducts 13 and 14. From these circumferential grooves 15, alternating control openings 31 and 32 formed by axial grooves, the number of which corresponds to double the number of teeth on the gear 1, while the number of the guide openings 9 corresponds to the number of teeth on the gear ring 2. As a result, the displacement chambers 7 formed between the gear wheel 1 and the one tooth which has a more prominent 20 gear ring 2 are filled and emptied with pressurized liquid in the correct order. Thus, swivel valve 28 and inner circumference 10 of the housing act in the usual manner as a control swivel device which establishes the proper connection between the displacement chambers 7 and the pressure and low pressure connection of the machine, respectively. Between houseable parts, e.g. To the tooth ring 2 and the end wall 3, a rubber sealing ring 34 is arranged in a ring groove 33.

In a side wall of the gear 1, a ring groove 36 is arranged between the breakthrough 26 and the teeth 35 of the gear 1 in which 30 is a sealing ring 37 of the polytetrafluoroethylene.

This sealing ring substantially completely seals the gap between the pinion 1 and the end wall 3. Thereby, the leakage loss is limited to the gap between the gear 1 and the other end wall 4, which has a variable length over the circumference.

In FIG. 2, the opening 27 is dotted. The shortest gap is obtained in the position shown by the gear 1 between the tooth base on both sides of the lower tooth 35 and the opening 27. But since a leakage path between gear 1 and end wall 3 is blocked, the gear 1 can have a small circumference so that it shortest gap length between gears 1 and middle wall 4 e.g. only amounts to 1.5 mm, without the need to fear excessive leakage.

Since the sealing ring 37 prevents a leakage current, without pressure 10 of the sealing ring in the area 38, a pressure equal to the pressure in the adjacent displacement chambers 7 can be built up. If the gear 1 should thereby be pressed too hard against the end wall 4, each tooth 35 on it adjacent to the sealing ring 37, two recesses 39, 40 are separated which are separated from each other by a radial section 41. In this way, pressure compensation faces 42 appear, which also act on the pressure of the adjacent displacement chamber 7.

These recesses may additionally be dimensioned such that together with the internal tooth of the gear 2 they constitute a secondary commutation in connection with the guide openings 9, 31, 32. Adjacent chambers can be held above these recesses until a tooth head of the tooth ring 2 either come into contact with a tooth base or with a tooth head in the region of the portion 41. of the gear wheel 1, thereby inaccuracies in the work of the inner circumference 10 and the rotary slider valve 28 can be largely compensated.

In FIG. 4, a variation is shown in which the sealing ring is formed in two parts and consists of an elastic sealing ring 37 in the ring groove 36 and a metallic sealing ring 43. This metallic sealing ring 43 remains fixed with respect to the sealing ring 37, but gives a slight friction with respect to the end wall. third

147950 7

It is possible to vary this construction in many directions. For example, the swivel slide valve 28 may be disc-shaped instead of cylinder-shaped. The end wall 4 may also immediately serve as a distributor plate.