Patent Application
20140161656
The invention relates to a transmission pump, in particular a transmission oil pump of an automatic transmission, in accordance with the preamble of patent claim 1.
From the state of the art, transmission pumps, particularly transmission oil pumps, which are driven by the internal combustion engine and/or an electric motor of the vehicle, are known. Pump systems that include two pumps, which are powered by the internal combustion engine and/or an electric motor, are also known. In addition, variable displacement pumps, double-flow or multi-flow pump concepts along with pumps in combination with a pressure accumulator are known.
Under the state of the art, transmission pumps and compressors designed as gear pumps and vane cell pumps are constructed free of axial forces, which is to achieve a run of the pump gear wheels within the pump housing that is as friction-free as possible.
Furthermore, producing the pump housing from cast iron and the pump cover or oil guide flanges as light metal components from aluminum or magnesium casting is also known from the state of the art.
The design of the pump gear wheels free of axial forces gives rise, in a disadvantageous manner, to a type of axial oscillation of such gears and/or vanes, whereby the proportion of the pendulum swings in the direction of the pump housing and the pump cover and/or oil guide flange are nearly the same.
This axial oscillation of the pump gear wheels, which are usually produced from steel or through sintering, in the direction of the light metal component, i.e. the pump cover or the oil guide flange, leads to a higher wear of the inner surface of the pump.
DE 43 15 432 A1 discloses a conveyor unit for conveying fuel from a storage tank to an internal combustion engine of a motor vehicle with a conveying pump, which is formed as an internal gear pump and, as a conveyor link, features an internally toothed gear rim and a gear combed with it, whereas the pumping chambers formed between the toothing are limited, in the direction of the axis of rotation, on the one hand by a cover plate and on the other hand by a guard plate, and in the cover plate form a suction opening and a pressure opening of the conveyor pump. In addition, the gear is pressed through a pressing element against the guard plate, by which this is held in the structure at a base plate. This ensures that the gear rim and the gear are not able to carry out any axial movements, which leads to the fact that pressure pulsations of the pump and disrupting noises are avoided.
With the known conveyor unit, it is also provided that the front surface of the guard plate sliding on the base plate and the front surface of the base plate are matched to one another to optimize the friction conditions. The toothing of the conveyor link of the conveying pump can be designed as helical gearing, by which an axial force acting on the gear rim arises, through which this is pressed against the guard plate. This is to achieve the advantage that, between the guard plate and the gear rim, a positive-locking connection is required only in direction of rotation.
The design known from DE 43 15 432 A1 has the disadvantage that many components, such as (for example) pressing elements and guard plates, are required to achieve axial stabilization.
The present invention has the task of specifying a transmission pump, in particular a transmission oil pump of an automatic transmission, with which, in the operation of the pump, the pump gear wheels are led in an axial manner in the direction of the pump housing without any increased manufacturing or assembly effort, by which a sliding of the pump gear wheels on the surface of the pump cover and/or the oil guide flange, and thus an increased wear of the pump cover and/or the oil guide flange, is prevented.
This task is solved by the characteristics of patent claim 1. Additional arrangements and advantages under the invention arise from the subclaims.
Accordingly, what is proposed is a transmission pump, in particular a transmission oil pump of an automatic transmission, comprising a pump housing and a pump cover or an oil guide flange, with which in the case of a gear pump, the driving pump gear wheel and, in the case of a vane cell pump, the vane cell wheel, is driven through a pump carrier operatively connected to the pump drive shaft, whereas he pump carrier surface areas feature an inclination to the effect that, in the case of a gear pump, the driving pump gear wheel and, in the case of a vane cell pump, the vane cell wheel, is led in an axial manner in the direction of the pump housing, and arrives at the structure at the pump housing.
Within the framework of an additional form of the invention, it can be provided that, in the case of a gear pump, the toothing between the driving and the driven pump gear wheel likewise features a targeted inclination, such that it is also the case that the driven pump gear wheel (for example, in the case of an internal gear pump, the ring gear) is led in an axial manner and arrives at the structure at the pump housing.
In accordance with the invention, the pump housing is preferably designed as a cast iron housing, and the pump cover or oil guide flange is preferably designed as a light metal component made of aluminum or magnesium casting, for example.
The design under the invention prevents axial oscillation of the pump gear wheels in the direction of the light metal component, resulting in a significant reduction in wear. Furthermore, in the operation of the pump, when axially viewed, a uniform air gap arises between the pump gear wheels and the light metal component. In an advantageous manner, the degree of efficiency of the pump can thereby be increased.
Given the internal lubrication effect of cast iron, a purposeful, slight sliding of the pump gear wheels on the surface of the cast iron housing is not critical.
In the following, the invention is more specifically illustrated as an example on the basis of the attached figures. The following is shown:
The same reference signs designate the same components.
In
In accordance with the invention and referring to
In
Furthermore, in accordance with the invention and referring to the upper part of
In the example shown, the toothing 8 between the driving pump gear wheel 6 and the driven pump gear wheel 7 likewise features a targeted inclination, such that the driven pump gear wheel 7 is also led in an axial manner in the direction of the cast iron housing 2, by which it arrives at a defined structure 14 at the cast iron housing 2, as the bottom part of
As can be seen in the lower part of
The invention prevents axial oscillation of the driving pump gear wheel 6 and the driven pump gear wheel 7 in the direction of the pump cover 3 designed as a light metal component, which, in an advantageous manner, results in a significant reduction in wear and an increase in the service life of the transmission pump 1.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2011 080 048.4 | Jul 2011 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2012/061330 | 6/14/2012 | WO | 00 | 1/27/2014 |
