EP0003572A1 - Sliding vane pump - Google Patents

Abstract

1. A sliding vane pump, particularly a vacuum pump for increasing the braking power in motor vehicles, the rotor of which is mounted in a pump housing (1) on a hollow shaft (5) comprising a lubricant supply means, and is provided with vane foot chambers (10) which are connected to the hollow shaft (5) for receiving the stream of lubricant and which are provided at their one axial end with passages (7.2) to lead the stream of lubricant onto the circumference of the hollow shaft (5) and into the sliding bearing (7) disposed on said axial end between the outer circumference of the hollow shaft (5) and the housing (1), with the sliding vane pump comprising a discharge channel (13) which runs within the pump housing (1) and opens into the oil reservoir (14), characterized by the fact that the rotor mounted on the hollow shaft (5) is supported in cantilever fashion in two sliding bearings (6, 7) which are arranged at an axial distance with respect to each other, in the pump housing, that an annular channel (8) is enclosed between the two sliding bearings (6, 7), the hollow shaft (5) and the pump housing (1), which annular channel (8) comprises a discharge leading to the oil reservoir (14), and that either the discharge channel (13) of the pump opens into the annular channel (8) behind the second sliding bearing (7) adjacent the rotor, or that the discharge channel (13.1) of the pump opens into an annular chamber (12) in front of the second sliding bearing (7), which annular chamber (12) connects the vane foot chambers (10) to one another.

Description

The invention relates to a vane machine of the type specified in the preamble of claim 1.

Such a vane machine is known from DE utility model 77 08 908. Vane cell machines of this type, which operate as vacuum pumps, are mainly used to generate an auxiliary force for braking in motor vehicles. Various lubricant systems for lubricating the moving parts are already known for these vane cell machines. These systems have generally proven themselves. The vane machine is usually connected to the oil circuit of the motor vehicle engine. Very different operating conditions occur here, so that - depending on the application - it may be possible that not all parts of the machine are regularly supplied with lubricant. These operating states can be, for example, an oil level that is too low and / or cold, viscous oil in winter.

Since there are also relatively small lubricant holes in such pumps, on the one hand because of the small amount required and on the other hand because of the necessary pressure, it can happen that with extremely cold and therefore extremely viscous lubricating oil these holes are practically closed by the lubricating oil. It is therefore possible that the wing foot spaces are closed. This has the consequence that a vacuum is formed under the extending wing, so that the wing in its extending movement slowed down and even prevented. However, this means that it is no longer in contact with the inside wall of the housing, so that no suction space is formed, which means that the pump does not need to be pumped.

The object of the present invention is therefore to improve the lubricant circuit of the vane machine and to design such that the functionality of the vane machine is guaranteed under all operating conditions.

The solution to this problem results from the features of the characterizing part of the first claim.

The advantage of the invention is that by connecting the outlet channel and the lubricant run, an additional conveying effect occurs in the lubricant system, which ensures that the lubricant safely reaches all the necessary lubrication points. The connection is possible at any point within the lubricant supply.

Claim 2 describes a special design of the outlet channel and the connection to the lubricant flow. The development of the invention according to claim 3 is intended to ensure that only one direction of flow is reliably achieved regardless of the type and pressure level of the lubricant supply. This has the advantage that substantially smaller amounts of lubricant are sufficient than would be required without connecting the outlet channel and lubricant run.

A bearing of the pump shaft can advantageously be used as a throttle according to claim 4. The annular channel according to claim 2 is particularly suitable for accommodating the bearing. It is also possible to mount the rotor of the vane machine on the fly.

In order to achieve a closed lubricant circuit in the vane machine, in which the lubricant is only guided through internal bores and channels within the machine housing, the embodiment of the invention is proposed according to claim 5. This eliminates the additional effort for external lines. Furthermore, the danger is avoided that these external lines break, whereby the lubricant circuit is interrupted and serious damage to the vane machine occur.

If the vane machine is used as a vacuum pump, there is the further advantage that the inner space of the hollow pump shaft and the vane foot spaces are under atmospheric pressure, as a result of which the lubricant can be injected into the hollow pump shaft. This eliminates the seal between the injection nozzle and the hollow pump shaft. Furthermore, the wings are essentially stressed by centrifugal forces, and the frictional power of the wings is kept low.

Claim 6 achieves a seal-free axial limitation of the ring channel. Claim 7 describes a preferred alternative guide of the outlet channel of the vane machine. Here too, a sufficient conveying effect is exerted on the lubricant carried in the vane cell machine.

Suitable and easily manufactured connection channels within the lubricant circuit are described by claims 8 and 9.

Claim 10 describes an advantageous embodiment of the second machine bearing.

A further embodiment of the invention is characterized in that the wing foot spaces have an external connection (connecting bores) in one end wall of the housing, the external connection extending over a circular arc coaxial with the rotor axis of rotation, which circular arc starting in the direction of rotation of the pump from bottom dead center to a maximum to top dead center.

This always allows pressure equalization in the wing footwell and prevents the formation of a vacuum. It has been found that in the conditions prevailing in the middle latitudes temperatures of the circular arc on which the external connection is provided, needs to extend only in a region from bottom dead center on the basis of up to 100 ⁰ (degrees of angle).

Several channels arranged on the circular arc can serve as an external connection.

Instead of several channels, it is of course also possible to use a single channel whose passage cross section corresponds to that of the several channels. An external connection with a kidney-shaped passage cross section is also suitable.

The external connection can create a connection to the atmosphere. Only air, but also oil - under pressure or without pressure - can flow into the wing foot space when the wing is extended.

The invention is explained in more detail below with the aid of a preferred exemplary embodiment and with reference to the drawings. Here, the invention is described on the basis of a vane cell vacuum pump installed in a motor vehicle, but is not restricted to this.

• Fig. 1 einen Axialschnitt durch eine stehend eingebaute Flügelzellenpumpe mit diagonal verlaufendem Pumpenauslaßkanal;
• Fig. 2 einen Axialschnitt durch die Pumpe nach Fig. 1 mit einem spiralförmig verlaufenden Pumpenauslaßkanal;
• Fig. 3 einen Axialschnitt durch eine andere Flügelzellenvakuumpumpe mit Teilen ihres Antriebes;
• Fig. 4 eine Ansicht der antriebsseitigen Stirnplatte der Pumpe mit der erfindungsgemäßen Ausgestaltung der Außenverbindung der Flügelfußräume.

They represent:

• Figure 1 is an axial section through a standing vane pump with a diagonally extending pump outlet channel.
• FIG. 2 shows an axial section through the pump according to FIG. 1 with a spiral-shaped pump outlet channel;
• 3 shows an axial section through another vane vacuum pump with parts of its drive;
• Fig. 4 is a view of the drive end plate of the pump with the inventive design of the external connection of the wing foot spaces.

1 consists of a pump housing 1, which bears with its connecting flange on the schematically indicated motor housing 2. The motor housing 2 houses the oil reservoir 14. It is fastened by means of suitable connecting elements, for example screws and washers. The pump housing 1 is closed by a cover 3, which also contains the suction opening 4.

In the pump housing 1, the bored-out pump shaft 5 is mounted at the level of the fastening in the engine block in a first slide bearing 6 and shortly before the pump chamber in a second slide bearing 7. The first slide bearing 6 is formed by the housing 1. The second slide bearing 7 is an exchangeable slide bearing which is fitted into an annular channel 8 in the housing 1. This ring channel 8 runs from the pump chamber to the first slide bearing 6. The slide bearing 7 has one or more axially extending lubrication grooves 7.1 distributed over the circumference and one or more oil return grooves 7.2.

The upper cantilevered end of the pump shaft 5 carries four radially arranged wings 9 which can extend and retract radially. Such a pump is described for example in DE utility model 77 07 853. The wing root spaces 10 are connected to the bore in the pump shaft 5 via a radial annular space 11 (recess in the cover 3). Furthermore, the wing root spaces 10 are connected to the second slide bearing 7 via a further annular space 12 in the pump housing.

The pump outlet channel 13 runs from a suitable point in the pump chamber diagonally in the pump housing 1 to the ring channel 8. It leaves the ring channel 8 diametrically to its inlet and - when using the vane machine in a motor vehicle engine - opens into the motor housing.

The function of the lubricant circuit will be explained in more detail below.

The pump shaft 5 is driven by a suitable drive - when used in a motor vehicle engine - for example via a gear pair from the camshaft. It evacuates the storage space of a brake booster (not shown here) via the intake manifold 4.

For the lubrication of all moving parts within the pump, lubricated oil is usually injected through the bored pump shaft 5. The oil is usually delivered under pressure from the engine oil pump (oil reservoir 14). The oil is introduced into the pump shaft 5 at such a pressure that it reaches the annular space 11. From there it arrives at the wing foot spaces 10. It also reaches the wing foot spaces 10 through the bores for the coupling pins 15, which are arranged on the underside of the wing. Because of the centrifugal forces, it is distributed from the wing foot spaces 10 to the sliding surfaces of the wings in the housing 1 or on the cover 3.

The oil from the wing foot spaces 10 passes through the ring channel 12 to the second bearing 7. The flow through the bearing 7 occurs through the oil return grooves 7.2 and is supported by the fact that the air flowing out through the pump outlet channel 13 passes through the ring channels 18 below the bearing 7. This creates a suction effect that can propagate through the grooves 7.2 in the bearing 7 into the annular space 12 and the wing root spaces 10. The bearing 7 is supplied with oil via the lubrication groove (s) 7.1. The oil entering the ring channel 8 is largely discharged into the engine compartment (oil reservoir 14) with the compressed air. A portion of the oil from the ring channel 8 is used to lubricate the first bearing 6. The air entering the engine compartment is returned to the air filter via a line due to environmental protection regulations. The oil collects again in the oil pan, where it can be collected again by the oil pump.

2, the pump outlet channel 13.1 does not run to the annular channel 8, but in spiral turns to the annular space 12. The spiral turns are therefore necessary so that the rotating vanes 9 do not get caught on the outlet channel 13.1. In this embodiment, the air enriched with lubricating oil is pressed due to the pumping action of the pump through the bearing 7 and the grooves 7.2 arranged therein. The air / oil mixture is then discharged from the annular duct 8 into the engine compartment in the manner described in FIG. 1.

If the vane machine is not used as a pump in a motor vehicle, motor housing 2 should be understood to mean any other housing to which the machine is attached. Preference is given to housings which contain a lubricant supply for the machine, since in these cases no external lubricant supply and discharge lines have to be provided. However, if external lines are used, it is possible to feed the lubricant through the cover 3 directly into the annular space 11 and to remove it from the annular space 12 with the exhaust air. This discharge line is then connected to any suitable lubricant reservoir 14.

In Fig. 3, the section through another embodiment of a vane pump was made such that the two visible vanes 104 are at the same distance from the axis of rotation.

In the pump housing 101, the pump shaft 102 is rotatably supported in the slide bearings 114 and 115. The pump shaft 102 supports the rotor 103 in a rotationally fixed manner. Each wing 104 has two pins 105 which slide in bores 106 in the rotor 103 and in the pump. The pins 105 opposite wings 104 are arranged at the same height. This has the advantage that if a wing 104 is jammed, the opposite wing can push it over the pins 105.

The pump shaft 102 is designed as a hollow shaft and has a flange 107 in the direction of its drive. Attached to this flange is the driver 108, the free end of which is attached to the driver disk 109 of a pump drive motor, the shaft 110 of which is sketched in FIG. 3.

The driver 108 is arranged in a housing 111 which at the same time carries the pump housing 101 and contains the inlet and outlet channels of the pump. At the other end, the housing 111 is flanged to the motor housing, for example of a motor vehicle. The driver 108 is drilled out at the level of the pump shaft 102, i.e. the opening of the hollow shaft is not completely closed. The lubricant, usually oil, is supplied under pressure through the lubricant line 112 arranged in the axis of rotation of the pump drive motor shaft 110. The rigid feed line 113 is screwed or pressed into this shaft 110 in its axial extension. This feed line 113 ends in the pump shaft 102.

The front end of the pump shaft 102 ends in a storage chamber 116. From this chamber 116, an axially arranged groove 117 runs through the front slide bearing 114, which is formed by a sintered metal bush 122.

The rear slide bearing 115 is formed by the housing 111, which in this case consists of aluminum or an aluminum alloy. A bore 121 leads to this bearing, which is inclined at an angle to the horizontal. Depending on the bearing material and size, several holes 121 can of course be arranged. These bores 121 end in an annular space 120 which connects the individual wing foot spaces 119 on the end face. In the exemplary embodiment, the annular space 120 does not extend as far as the pump shaft 102 in order not to reduce the bearing width. With appropriate bearing dimensions, it is of course also possible to extend the annular space 120 to the pump shaft 102. Then the bore 121 can also be formed as an axially extending groove.

The lubricating oil required for lubrication passes through the lubricant line 112 and the supply line 113 into the pump shaft 102.

Due to the oil pressure, it emerges as a jet that sprays into the storage chamber 116. Due to the dynamic pressure and the lack of drainage, it is pressed through the groove 117, which lies in the pressure-relieved area of the bearing, into the slide bearing 114 and - favored by the centrifugal force - through the bores 106 into the wing foot spaces 119. From there, it can lubricate both the guides of the vanes 104 and the contact surfaces of the vanes 104 with the inner wall of the pump housing 101. The wing foot spaces 119 convey the oil further into the annular space 120, from where it passes through the bore 121 to the bearing 115. The supply of the bearing 115 with oil is supported by the retracting and extending movement of the vanes 104, since the oil present in the vane spaces 119 is displaced into the annular space 120 and thus into the bore 121 by the retracting movement of the vanes 104. This displacement effect is dependent on the diameter of the bore 106 or the gap between the pins 105 and the inner wall of the bores 106.

In order to produce a regulated lubricant circuit, passage openings (connecting bores) 125 are provided which connect the annular space 120 to the driver space 127. The driver space 127 is connected to the oil sump of the pump drive via return lines (not shown here).

As shown in FIG. 4, the passage openings 125 are arranged in a range from bottom dead center to almost 100 ^° (angular degree) in the direction of rotation of the pump.

If there were only a single passage opening 125, cold, viscous lubricating oil would close it when starting in winter. Since the other supply lines 117 to the wing foot spaces 119 are more or less gap-shaped, these are also closed by the viscous lubricant. If a wing 104 now had to extend, a vacuum would form in the wing foot space 119, which prevents the wing 104 from moving out.

Since several through openings 125 are now provided according to the invention, it is impossible - as tests have also shown - that all openings 125 are closed at the same time. A pressure equalization can therefore always take place between the wing foot space 119 and the driver space 127, in which atmospheric pressure always prevails. This ensures that the pumping action of the vane pump is not impaired under all possible operating conditions, in particular at very low operating temperatures, and that atmospheric pressure prevails in particular under the vane 104 during its extension or acceleration phase. In addition to oil, air can also be sucked in from the entraining space 127. A regulated lubricant circuit is also maintained at all times.

REFERENCE SIGN LISTING

• 1 pump housing
• 2 motor housing
• 3 lids
• 4 suction opening
• 5 pump shaft
• 6 first camp
• 7 second camp
• 7.1 Lubrication grooves
• 7.2 Oil return grooves
• 8 ring channel
• 9 wings
• 10 wing footwell
• 11, 12 annulus
• 13 pump outlet channel
• 13.1 Pump outlet channel in Fig. 2
• 14 oil reservoir
• 15 coupling pins
• 101 pump housing
• 102 pump shaft
• 103 rotor
• 104 wings
• 105 pens
• 106 holes
• 107 flange
• 108 drivers
• 109 drive plate
• 110 pump drive motor shaft
• 111 housing
• 112 Lubricant line
• 113 rigid supply line
• 114) plain bearing 115)
• 116 storage chamber
• 117 groove
• 119 wing footwell
• 120 annulus
• 121 hole
• 122 sintered metal bushing
• 125 passage opening (connecting hole)
• 127 driver room

Claims (15)

1. vane machine, especially vacuum pump for brake boosters in motor vehicles, consisting of a shaft mounted in a housing, which is connected in a rotationally fixed manner to a rotor, in which vanes can be slid in radially arranged slots, which blades, with their ends protruding from the rotor, slide along a stroke curve arranged in the housing, which housing is provided with an inlet and outlet channel and envelops at least one suction and pressure chamber, characterized in that an oil flow is established in the wing foot spaces (10) by connecting the wing foot spaces (10) on the oil outlet side (ring channel 12) to the outlet channel (13) and / or an oil reservoir (14). 2. vane machine according to claim 1,
characterized,
that the connection between the outlet channel (13) and the wing foot spaces (10) is designed as an annular channel (8) surrounding the shaft (5), which the outlet channel (13) intersects. 3. vane machine according to claim 1 or 2,
characterized,
that a throttle is arranged in the connection between the outlet channel (13) and the wing foot spaces (10). 4. vane machine according to claims 2 and 3,
characterized,
that the throttle is designed as a slide bearing (7) with lubrication grooves (7.1) and return grooves (7.2). 5. Vane machine according to one of the preceding claims,
characterized,
that the oil is supplied by the shaft (5) designed as a hollow shaft, the shaft (5) projecting into the oil reservoir (14). 6. Vane machine according to one of the preceding claims,
characterized,
that the annular channel (8) is limited on the one hand by the slide bearing (7) designed as a throttle and on the other hand by the machine housing (1). 7. vane machine according to claim 6,
characterized,
that the outlet channel (13) is arranged spirally in the front bottom of the housing (1) and forms a closed channel with the front sides of the rotor and the vanes (9) and between the slide bearing (7) and the wing root spaces (10) in the annular channel ( 8) opens and leaves it in the axial direction on the oil reservoir (14). 8. Vane machine according to one of the preceding claims, in particular claim 5,
characterized,
that the hollow shaft is connected via an annular space (11) to the wing foot spaces (10). 9. Vane machine according to one of the preceding claims,
characterized,
that the wing foot spaces (10) are connected to the annular channel (8) via a further annular space (12). 10. Vane machine according to one of the preceding claims,
characterized,
that the ring channel (8) axially delimiting housing (1) is designed as a further slide bearing (6). 11. vane machine according to claim 1,
characterized,
that the wing foot spaces (119) have an external connection (connecting bores (125) in one end wall of the housing (111), the external connection extending over an arc coaxial with the rotor axis of rotation, which arc in the direction of rotation of the pump starting from bottom dead center up to a maximum of top dead center is enough. 12. Vane pump according to claim 11,
characterized,
that the arc extends in the direction of rotation of the pump from bottom dead center to about 100. 13. Vane pump according to claims 11 or 12,
characterized,
that the external connection consists of a single channel with a kidney-shaped passage cross section. 14. Vane pump according to one of the preceding claims 11 to 13,
characterized,
that the external connection consists of several individual connecting bores (125). 15. Vane pump according to one of the preceding claims 11 to 14,
characterized,
that atmospheric pressure is applied to the wing footwell (119) having the extending wing (104) and that lubricating oil and air are sucked in through the outer connection.

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