DE8707735U1 - Reversible gear machine (pump or motor) - Google Patents

Description

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ROBERT BOSCH CMBH/ 7000 Stuttgart 1 Reversible gear machine (pump or motor) State of the art The invention is based on a gear machine of the type

of the main claim« Such a known gear machine has the

Disadvantage/ that the pressure fields for reversing operation are still

are optimally coordinated" so that , for example, when used as

Gear motor still has some difficulties in starting up · | This is due to the fact that when the engine starts the hydraulic |

mechanical force on the sealing plate must be correctly dimensioned/ so that |

the motor can start quickly. After starting, the |

Sealing plate in sealing contact with the gear side surfaces i-

is standing, whereby the excess force from the pressure fields is not very

(^ should be large/ in order to keep frictional forces small.

Advantages of the invention

The gear machine according to the invention with the characterizing features of the main claim has the advantage that the design of the pressure fields is perfected so that the hydraulic forces required for the current operation are always exerted on the sealing plate. This improves the service life, the noise and the operating behavior of the gear machine. In particular, the internal housing forces are also reduced.

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drawing

An embodiment of the invention is shown in the following description and drawing. Figure 1 shows a longitudinal section through a gear motor, Figure 2 shows a cross section along H-II according to Figure 1, Figure 3 shows a cross section along HI-III according to Figure 2 and Figure 4 shows a detail.

Description of the embodiment

/ The gear motor has a housing 10/ the interior 11 of which is closed by two covers 12, 13. In the interior, two gears 14, 15 mesh with each other in external engagement/ the shafts 16, 17 of which are mounted in bushing- or eyeglass-shaped bearing bodies 18, 19, which can be slightly displaced axially and radially in the housing. The shaft 17 has an extension 23 that penetrates outwards through a hole in the cover 13 and is sealed there by a sealing ring 24.

Between the bearing body 18 and the gear wheel side surfaces, a sealing plate 26 is arranged, on the side of which facing away from the gear wheels, pressure fields are formed, as shown clearly in particular in Figure 2. The pressure fields &lgr;-D are limited by a seal 27, which is mounted in a suitable hat in the front ( surface of the bearing body 18. Here in particular Figure 2

The seal consists of two concentrically running, roughly eyeglass-shaped rings 28, 29, whereby the inner rings 29 are connected to each other by a web 30, which runs in the imaginary axial direction of the center of the gear shafts. The inner and outer rings are also connected to each other by webs 31, 32, which run roughly radially from the inner rings outwards, roughly at right angles to the web 30, whereby their axial direction also refers to the center of the gear shafts. The

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The diameter of the outer rings 28 extends to the edge of the inner space 11 bsvi.» up to the level of the sealing plate 26, while the inner rings 29 have a small distance to the hole bores.

In this way, two pressure fields A and B are created next to each other on both sides of the web 30 and two diametrically opposed pressure fields C and D, which are located on the outside in relation to the longitudinal extent of the seal 28. A bore 34, 35 penetrates into each of the pressure fields A and B, which pass through the sealing plate and open into the tooth gaps below. Two bores 50, 51 penetrate into the interior from the outside at the level of the gear wheels 14, 15 and run parallel to the axis; these bores serve to supply and discharge pressure medium.

A bore 40, 41 also penetrates into the outer pressure fields C and D, which also penetrate through the sealing plate and are connected to bores 42, 44 and 43, 45 running on the same axis in the bearing body 18 or cover 12. There they are connected to a line 46 to which a pressure valve 47 is connected, »suitably an electromagnetically actuated proportional valve, with which the pressure in the pressure fields C and D is controlled. The bores 40, 41 are designed as throttle bores.

The seal 27 is shown in more detail in the section according to Figure 4. It is designed in two parts and consists of a support body 27A with a U-shaped cross-section, the underside of which rests against the sealing plate 26. The support body is made of a plastic, e.g. PTFE. A soft, rubber-like seal 27B is inserted into the support body, which has a cross-sectional shape shown in Figure 3. The seal 27 is arranged in a correspondingly shaped groove 48 in the bearing body 18. The sealing body 27B has two longitudinal grooves 27C, 27D on its part lying on the rounded groove base. A circumferential groove 49 runs around the bearing body at a short distance from the groove 48.

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It is assumed that high-pressure pressure medium is fed to the bore 50. This now drives the gears so that a torque can be taken from the hole 23. The pressure medium leaves the bore 51 on the low-pressure side. In the pressure fields A and B, the excess or outlet pressure now prevails via the bores 34 and 35. The pressure valve 47 is opened so that there is no pressure in the pressure fields C and D. This is so that the sealing plate is not pressed too strongly against the gear side surfaces. This keeps the frictional forces low and the gear motor can start up easily. After starting the gear motor

/ . the pressure fields C and D are increased by increasing the closing of the V j

Switching valve is subjected to higher pressure so that the sealing plate

26 is pressed more strongly against the gear wheel side surfaces. This means that no more pressure medium can flow along the gear wheel side surfaces from the high pressure side to the low pressure side, so that the efficiency of the gear motor remains correspondingly high. The throttle holes 40, 41 ensure that only a small flow of pressure medium is diverted from the gear machine.

It should also be noted that a sealing plate 26 with corresponding pressure fields can also be arranged on the other gear side surface. However, this is not absolutely necessary.

(J) Of course, the gear machine can be operated both as a hydraulic motor and as a gear pump. It is reversible; if high-pressure fluid is supplied to the bore 51, then field B is subjected to high pressure and field A to low pressure.

The groove 49 prevents high-pressure fluid from leaking along the outside of the bearing body to the covers. This means that the inside of the housing remains largely pressure-relieved.

Claims (5)

&bull; · · t 11 &bull; · * t t 1 S I ■ ■ «If < &bull; · ■· II lit R. 21224 18.5.1J87 Wd/Kc ROBERT BOSCH GMBH, 7000 Stuttgart 1 Claims 1. Reversible gear machine (pump or motor) with two gears (14, 15) meshing externally and with a sealing plate (26) arranged on at least one of their side surfaces, which is acted upon by pressure fields (A to D) formed on its side facing away from the gears, which are delimited by a sealing arrangement (27) consisting of two concentrically running, approximately spectacle-shaped rings (28, 29) which are connected to one another by webs, of which the outer rings run along the inner wall of the housing, the inner ones close to the gear shafts, characterized in that the two inner rings (28, 29) are connected on an imaginary connecting line running through the centers of the gear shafts by a first web (30), that in addition, two of the inner rings each run radially and approximately perpendicular to the first web in opposite directions. webs (31, 32) and are connected to the outer rings, whereby two diametrically opposed pressure fields (C, D) are produced, which are subjected to a pressure controlled by a pressure valve (46) via bores (40, 41) opening into them, and that the two pressure fields (A, B) formed between the approximately radially extending webs (30, 32) and the first web (30) are connected to the respective inlet or outlet (50, 51) via bores (34, 35) penetrating the sealing plate (26). Il MM * I With ti I I * · M If· I *i* · · 1 lit· &bull; ■ · I 1 · &bull; · I ·&Igr; 1 > ■ * 111· - 2 - 21224 2. Machine according to claim 1, characterized in that the sealing arrangement is formed in two parts and consists of a support ring (27a) made of plastic, which lies directly on the sealing plate (26), and a sealing body (27B) made of softer material inserted into the support ring, and that the sealing arrangement (27) is located in a hat (48) formed in the front side of the bearing body. 3. Machine according to claim 1 and/or 2, characterized in that sealing plates (26) with corresponding sealing arrangements (2?) are arranged on both sides of the gears. 4. Machine according to one of claims 1 to 3, characterized in that a small circumferential hat (49) is formed at a short distance from the sealing arrangement (27) on the outer circumference of the bearing body. 5. Machine according to one of claims 1 to 4, characterized in that the pressure medium for applying pressure to the pressure fields (C and D) is taken from the pressure chamber of the machine, namely via throttle bores (40, 41) which are connected to the pressure valve (47) to which a container is connected via bores (43, 45) penetrating the bearing bodies, the pressure fields (1, D) and a housing cover (12). 6« Machine according to one of claims 1 to 5, characterized in that the bores (40, 41) opening into the pressure chambers (C, D) are designed as throttle bores. ■ I Mtl Il 1 I I I I I I I I I 1 I I Il I Ii ill I f Il II III I I I I I I i i I I I I I I I