CN103201475A - Mechanical coolant pump - Google Patents

Abstract

The present invention refers to a mechanical coolant pump 10 for an internal combustion engine. The pump 10 comprises a stationary cylindrical pump housing 12 with an interna! pneumatic actuator 13 which is supplied by a pneumatic supply means 15 supplying a low-pressure, i.e. a pressure below the atmospheric pressure. Further, the pump 10 comprises a pump wheel 18 rotatably fixed with a pump wheel shaft 20, whereby the pump wheel shaft 20 is rotatably supported by the pump housing 12. The pump wheel shaft 20 is connectable to a separate driven shaft 22 by an internal pneumatic clutch unit 11, whereby the driven shaft 22 is directly connected with a pulley-wheel 24 which is driven by a driving belt. The interna! clutch unit 11 comprises a ciutch disk 26 which is completely fixed to the driven shaft 22 or, alternatively, to the pump wheel shaft 20, and an axfaily slidable clutch disk 28 which is siidably arranged at the pump wheel shaft 20 or, alternatively, at the driven shaft 22. The slidable clutch disk 28 is rotatably fixed to the pump wheel shaft 20 or, alternatively, to the driven shaft 22 and is axia y actuated by the pneumatic actuator 13.

Description

mechanical coolant pump

technical field

The invention relates to a mechanical coolant pump for an internal combustion engine.

Background technique

A mechanical coolant pump is a coolant pump that is driven by the internal combustion engine itself, eg by means of a drive belt to drive the coolant pump pulley. The pulley drives the rotor shaft or drives a pump wheel rotatably fixed on the rotor shaft. The rotational speed of such a coolant pump is proportional to the rotational speed of the engine's crankshaft, allowing the coolant pump to run for extended periods of time, even when the engine does not require any coolant flow. This unnecessarily increases the fuel consumption of the internal combustion engine. Therefore, a switchable coolant pump is used to optimize the energy consumption of the system. In particular, as long as the internal combustion engine is cold, no coolant flow is required and the coolant pump can be switched off, with the result that the warm-up phase of the internal combustion engine is shortened, exhaust emissions are reduced and fuel consumption is reduced.

A prior art switchable mechanical coolant pump is known from DE 10 2006 039 680 A1. The disclosed coolant pump has an internal mechanical clutch disposed within the pump housing. A mechanical clutch is provided by the impeller-side end of the rotor shaft and the impeller so that the rotor shaft can be disengaged from the impeller, for example during the warm-up phase of the internal combustion engine. The mechanical clutch of such a coolant pump is controlled by a separate external actuator connected to the opposite end of the rotor shaft. External actuators require additional installation space in the engine compartment.

Contents of the invention

It is therefore an object of the present invention to provide a compact mechanically switchable coolant pump.

This object is achieved with a mechanical coolant pump having the features of claim 1 .

A mechanical coolant pump for an internal combustion engine according to claim 1 comprising a fixed cylindrical pump casing with an internal pneumatic actuator supplied pneumatically to a low pressure (ie a pressure below atmospheric pressure) device supply. Furthermore, the pump comprises a pump impeller which is rotatably fixed on a pump impeller shaft, wherein the impeller shaft is rotatably supported by the pump casing. The pump impeller shaft is connectable to a separate driven shaft via an internal pneumatic clutch unit, where the driven shaft is directly connected to a pulley driven by a drive belt. The internal clutch unit comprises a clutch disc fixed entirely to the driven shaft or alternatively to the pump impeller shaft, and an axially slidable clutch disc slidably arranged on the pump impeller shaft or alternatively the driven shaft. A slidable clutch disc is rotatably fixed to the impeller shaft, or alternatively the driven shaft, and is actuated axially by a pneumatic actuator.

The internal pneumatic actuator uses low pressure to actuate the clutch unit, more precisely, the slidable clutch disc. Low pressure is supplied by a pneumatic supply. The pneumatic supply means can be represented by the intake section of the internal combustion engine and the pneumatic valves, so that the coolant pump does not require external actuators. This minimizes the size of the switchable coolant pump, so that the required installation space is minimized compared to a switchable coolant pump with a separate external actuator.

Preferably, the pump wheel shaft or output shaft has a longitudinal slide at the clutch-side end of the shaft, on which the slidable clutch disk is arranged. The end portion may be defined by a reduced cross-section compared to the rest of the shaft. The slidable clutch disc is rotatably fixed by a slide bar and is slidably arranged on the slide bar. Axial movement of the slidable clutch disc into the disengaged position is limited at the opposite end by radial stop surfaces such as circular steps in the shaft.

According to a preferred embodiment, the slidable clutch disc is pretensioned into the engaged position by a pretensioning element, preferably a compression spring. The pretensioning element is preferably supported by a shaft, for example by a spring support plate fixed to said shaft. The spring support plate is the mechanical support for the pretensioning element. Pre-tensioning to the engaged position makes the pump fail-safe so that operation or cooling of the engine, respectively, is guaranteed even if the actuator fails. When required, eg during a warm-up phase of the engine, the clutch can be disengaged by a pneumatic actuator fed by a pneumatic supply device. The pneumatic supply device includes: an intake portion that supplies low pressure; a pneumatic valve; and a pneumatic control unit that controls the pneumatic valve.

According to a preferred embodiment, the internal pneumatic actuator is defined by a slidable clutch disc and a pump housing. The clutch disc is an integral part of the pneumatic actuator.

Preferably, the pump housing has a pneumatic opening arranged axially between the slidable clutch disc and the pump wheel or alternatively a pulley. The pneumatic opening is connected to a pneumatic supply. The slidable clutch plate can be disengaged from the fixed clutch plate by use of an internal pneumatic actuator fed by a pneumatic supply. Thus, the pneumatic actuator acts against the force of the pretensioning element or the force of the compression spring, respectively.

Preferably, the circumference of the slidable clutch disc has an annular sealing element which seals the annular gap between the slidable clutch disc and the inner side wall of the circular pump housing. The sealing element must ensure that the internal pneumatic actuator is airtight so that the slidable clutch disc can be disengaged from the fixed clutch disc by means of the pneumatic actuator or low pressure, respectively. The sealing element may be, for example, a lip seal or a Teflon element.

According to a preferred embodiment, the gap between the slidable clutch disc and the pump wheel shaft or alternatively the driven shaft has a shaft seal so that the gap is closed gas-tight. Thus, the pneumatic actuator is able to disengage the slidable clutch disc from the fixed clutch disc by supplying the pneumatic actuator with a low pressure using the pneumatic supply means.

Description of drawings

Describe a kind of preferred embodiment of the present invention with reference to accompanying drawing, in the accompanying drawing:

Figure 1 shows a cross-sectional view of a mechanical coolant pump.

Detailed ways

FIG. 1 shows a mechanical coolant pump 10 for supplying coolant to an internal combustion engine. The mechanical coolant pump 10 comprises a stationary circular pump housing 12 with an internal pneumatic actuator 13 , a pump wheel 18 with a pump wheel shaft 20 and a separate driven shaft 22 directly connected to a pulley 24 .

The shafts 20, 22 are rotatably supported at each axial end of the shafts 20, 22 by roller bearings 40, 41 and friction bearings 32, 33, respectively. The pump wheel shaft friction bearing 32 is a sealing device that seals the pneumatic chamber 50 against ambient pressure.

The driven shaft 22 may be connected to the impeller shaft 20 via the internal pneumatic clutch unit 11 positioned within the pump housing 12 . The clutch unit 11 comprises a fixed clutch disc 26 and an axially slidable clutch disc 28, the fixed clutch disc is axially and rotatably fixed to the driven shaft 22, and the axially slidable clutch disc is arranged on the pump wheel shaft 20. clutch side end and is actuated axially by the internal pneumatic actuator 13.

The clutch-side end of the pump wheel shaft 20 has a smaller cross-sectional diameter than the main part of the pump wheel shaft 20 and has a longitudinal slide bar 34 on which the slidable clutch disc 28 is axially slidably arranged and rotatably fixed superior. The gap between the slidable clutch disk and the pump wheel shaft 20 or the sliding rod 34 is sealed substantially gas-tight by the shaft seal 17 . Axial movement of the slidable clutch disc 28 into the disengaged position is limited by a lateral stop surface 44 at the opposite end of the impeller shaft 20 , for example by a circular step at the shaft 20 .

The slidable clutch disc 28 is pretensioned into the engaged position by a pretensioning element 36 which is a single compression spring positioned around the impeller shaft 20 . The compression spring acts on the force-bearing surface 27 of the slidable clutch disc 28 with a constant pressure, so that no tilting movement occurs, and the slidable clutch disc 28 can be effectively prevented from being stuck on the inner wall 30 of the pump housing 12 . The pretensioning element 36 is supported by the pump wheel shaft 20 via a spring support ring 42 which is fastened directly on the pump wheel shaft 20 .

The circumference of the slidable clutch disc 28 has an annular pneumatic sealing element 38 . The sealing element 38 substantially, but not completely, hermetically seals the annular gap between the inner side wall 30 of the circular pump housing 12 and the slidable clutch plate 28 .

The pneumatic actuator 13 is defined by a slidable clutch disc 28 and a circular pump housing 12 . A pneumatic actuator 13 is arranged inside the pump housing 12 . The pump housing 12 has a pneumatic opening 16 which connects the pneumatic actuator 13 and the pneumatic supply 15 . The pneumatic supply device 15 includes an engine intake portion 45 that supplies low pressure, a pneumatic valve 19 and a pneumatic control unit 21 that controls the pneumatic valve 19 . The pneumatic opening 16 is positioned axially between the pump wheel 18 and the slidable clutch plate 28 . During the warm-up phase of the cold internal combustion engine, the slidable clutch plate 28 can be disengaged by the pneumatic actuator 13 by opening the pneumatic valve 19 . When the warm-up phase is complete and the engine is hot, the pneumatic valve 19 is closed, allowing the pressure in the pneumatic chamber 50 to slowly build up to atmospheric pressure via the pneumatic leakage of the pneumatic chamber 50 .

The mechanical coolant pump 10 can be mounted directly to the engine block via the flange 48 .

Claims (9)

1. mechanical type coolant pump (10) that is used for internal-combustion engine comprising:

Fixed pump shell (12) has the inside pneumatic actuator of being supplied with by pneumatic supplier (15) (13);

Pump impeller (18) has Pump wheel shaft (20), and described Pump wheel shaft (20) is rotatably supported by described pump case (12);

Independent driven shaft (22) directly is connected with pulley (24), and described driven shaft (22) can be connected to described Pump wheel shaft (20) by inner pneumatic clutch unit (11), and described clutch unit (11) comprising:

Fixing clutch disk (26) is connected to described driven shaft (22) or described Pump wheel shaft (20);

Clutch disk (28) in axial sliding, be arranged in slidably on described Pump wheel shaft (20) or the described driven shaft (22), wherein, described clutch disk in axial sliding (28) is rotatably fixed to described Pump wheel shaft (20) or described driven shaft (22), and

Described pneumatic actuator (13) activates described clutch disk in axial sliding (28) vertically.

2. mechanical type coolant pump as claimed in claim 1 (10), wherein, described inner pneumatic actuator (13) is limited by described clutch disk in axial sliding (28) and described pump case (12).

3. mechanical type coolant pump as claimed in claim 1 or 2 (10), wherein, described Pump wheel shaft (20) or described driven shaft (22) have slide bar (34) at the clutch side, and described clutch disk in axial sliding (28) is rotatably fixing by described slide bar (34).

4. as each described mechanical type coolant pump (10) of above claim, wherein, described clutch disk in axial sliding (28) is pre-tensioner to engagement positio vertically by pre-tensioner element (36).

5. as each described mechanical type coolant pump (10) of above claim, wherein, pneumatic opening (16) is arranged on the described pump case (12), be positioned at vertically between described clutch disk in axial sliding (28) and described pump impeller (18) or the described pulley (24), described pneumatic opening (16) is connected to described pneumatic supplier (15).

6. as each described mechanical type coolant pump (10) of above claim, wherein, the circumference of described clutch disk in axial sliding (28) has annular seal element (38), the gap between the madial wall (30) of described annular seal element sealing described clutch disk in axial sliding (28) and described pump case (12).

7. as each described mechanical type coolant pump (10) of above claim, wherein, provide the gland seal device (17) that is positioned between described clutch disk in axial sliding (28) and the described Pump wheel shaft (20).

8. as each described mechanical type coolant pump (10) of above claim, wherein, described pre-tensioner element (36) is supported by described Pump wheel shaft (20) or described driven shaft (22).

9. mechanical type coolant pump as claimed in claim 4 (10), wherein, described pre-tensioner element (36) is the compression spring.

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