Gear transmission unit with forced lubrication system

Abstract

A gear transmission unit, in particular for a motor vehicle, is provided with a forced lubrication system (3) for lubricating rolling bearings (B1, B2, B3) and / or other internal components of the transmission unit. The unit is provided with one or more auxiliary elements in the form of lubricant distribution boxes (S). Each distribution box (S) has a hollow body rigidly connected to the housing (2) of the unit adjacent to a corresponding channel outlet (5A) for supplying a flow of lubricant under pressure. The hollow body defines an internal lubricant distribution chamber (C) and has an inlet (8) connected to the channel outlet (5A) and two or more outlets (8) connected to further pipes or channels (5B) or chambers for supplying a flow of lubricant under pressure in parallel to the various components to be lubricated in the transmission housing (2).

Description

Technical Field

[0001] The present invention relates to a gear transmission unit, in particular for a motor vehicle, comprising:

[0002] - support housing,

[0003] - a plurality of shafts rotatably supported in a bearing housing by means of corresponding rolling bearings,

[0004] - a plurality of gears carried by the shaft and meshing with each other,

[0005] - a forced lubrication system for lubricating the rolling bearings and / or other internal components of the transmission unit, the forced lubrication system comprising:

[0006] - a supply pump for supplying lubricant, and

[0007] - a plurality of channels formed in the wall of the bearing housing of the transmission unit for carrying lubricant to the internal components to be lubricated. Background Art

[0008] Transmission units of the type indicated above, such as reduction and transmission units for motor vehicles, are ancient and have been in use for a long time. The use of a forced lubrication system offers a corresponding reduction in frictional internal losses compared to the more traditional solutions of wet transmissions, in which lubricant is displaced within the transmission housing by movable components themselves provided within the unit (such as the differential crown). In modern transmissions, improved efficiency is achieved by relying on dry lubrication, in which lubricant is supplied by a pump (preferably electrically actuated) to a network of channels formed within the transmission unit housing.

[0009] In some known transmissions, in order to reduce the complexity of the network of lubricant channels, forced lubrication is provided only to the uppermost components within the transmission housing. After the lubricant has wetted the upper components, it reaches the lower components due to gravity. Of course, this solution represents a compromise and has the disadvantage of not ensuring proper and controlled lubrication of the lower components of the transmission. Summary of the Invention

[0010] The main object of the present invention is to overcome the above-mentioned disadvantages.

[0011] In particular, the object of the present invention is to provide a transmission unit which allows suitable and controlled lubrication of all its components and which can be obtained with simple and rapid operation even from a transmission unit originally configured for operation with forced lubrication of the components in the upper part and with gravity lubrication of the components situated at the bottom of the transmission.

[0012] More generally, the invention aims to simplify the construction of the network of channels that must be provided within the structure of the transmission unit for the purpose of supplying a controllable flow of lubricant under pressure to all components to be lubricated within the transmission.

[0013] With regard to achieving one or more of the aims indicated above, the present invention provides a gear transmission unit having the features indicated at the outset of the present description and further characterized in that it is provided with one or more auxiliary elements in the form of a lubricant distribution box, the or each distribution box having a hollow body rigidly connected to the support housing adjacent to a respective channel outlet for supplying a forced flow of lubricant, and said hollow body defining an internal lubricant distribution chamber and having one inlet connected to said channel outlet and two or more outlets connected to further ducts or channels or chambers for supplying a flow of lubricant under pressure in parallel to the various components to be lubricated within the support housing.

[0014] Thanks to the provision of the above-mentioned lubricant distribution box, the operations necessary to convert the transmission unit to operate with proper and controlled lubrication of all the internal components of the unit become extremely simple, quick and inexpensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Further characteristics and advantages of the invention will become apparent from the ensuing description, given by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0016] - Figure 1 This is a diagram of the lubrication system of the transmission unit.

[0017] - Figure 2 is a perspective view of a detail of a gear transmission unit (ie, a speed reducer unit for an electric motor unit of a motor vehicle),

[0018] - Figure 3 Show Figure 2 The same detail of the gears has been removed in order to show the rolling bearings used to support the shaft on which the gears are mounted,

[0019] - Figure 4 for Figure 3 a further perspective view on an enlarged scale of a detail of the invention, wherein the rolling bearing has been removed in order to show the outlet of the channel for supplying a lubricant flow under pressure,

[0020] - Figure 5 The transmission unit according to the present invention is shown in FIG. Figure 4 the same details, wherein the two outlets of the channel for supplying lubricant are associated with connection parts for connection to a lubricant distribution tank,

[0021] - Figure 6 Shown Figure 5 The same details, where the distribution box is mounted at the connection part for the lubricant,

[0022] - Figure 7 is a perspective view of a transmission case, including a case body and a cover fixed thereto,

[0023] - Figure 8 For the distribution box body Figure 7 a perspective view on the opposite side of the side, and

[0024] - Figure 9 A perspective view of a section of a distribution box. DETAILED DESCRIPTION

[0025] exist Figure 1 In the drawings, reference numeral 1 generally designates a gear transmission unit, such as a gear reducer unit for a motor vehicle electric motor or a motor vehicle transmission. Unit 1 comprises a support housing 2 in which two or more shafts are rotatably mounted by means of rolling bearings, carrying gears that mesh with one another. Transmission unit 1 is provided with a forced lubrication system 3 comprising a feed pump 4 driven by an electric motor 5 for supplying a flow of lubricant (oil) under pressure to a network of internal channels 5 formed in the wall of support housing 2.

[0026] The example shown here relates to a transmission unit originally constructed with a network of channels 5 designed to directly supply a pressurized lubricant flow to the uppermost rolling bearings and / or other internal components of the unit located within the housing 2. In known solutions, the lubricant reaches the lowermost components due to gravity after it has already wetted the uppermost components. As previously indicated, this solution does not ensure proper and controlled lubrication of all internal components of the unit. The concept underlying the present invention is to retrofit a transmission unit constructed as described in this manner in an extremely simple and inexpensive operation to also achieve direct, forced lubrication of the lowermost components within the unit.

[0027] Figure 2 Details of the gears R1, R2, R3, R4 arranged in the unit 1 are shown. The gears R1-R4 are mounted on axes A1, A2, A3, which are parallel to each other and rotatably supported in the support housing 2 of the unit 1 by means of rolling bearings B1, B2, B3 ( Figure 3 ).

[0028] By way of example, in a transmission unit according to the prior art, lubrication of the rolling bearing B1 is obtained by supplying a flow of lubricant under pressure to the surface of the seat receiving the bearing. For this purpose, the channel 5 for supplying a flow of lubricant from the pump 4 opens at the channel outlet 5A at the surface of the seat 13 for the bearing ( Figure 4 ).

[0029] In the transmission unit according to the known art, the forced flow of lubricant leaving from the outlet 5A wets the bearing B1 , after which the lubricant continues to flow by gravity towards the lowest part of the support housing, lubricating the lowest bearing and / or other components located in the housing 2 .

[0030] In an exemplary embodiment of the transmission unit according to the invention, a lubricant distribution tank S is provided at the seat of the rolling bearing B1. In the example shown, the tank S comprises a hollow body made of plastic material, which is defined by a tank element S1 and a cover S2 fixed to the tank element S1 in any known manner, for example by welding or glue.

[0031] With reference also to the example shown, the box element S1 comprises two connecting parts 6 having holes 7 for engaging fixing screws for fixing the distribution box S to the transmission unit (wherein holes 14 are formed for engaging screws- Figure 5 ) structure.

[0032] The internal cavity C defined between the box element S1 and the cover S2 constitutes a lubricant distribution cavity.The main wall of the box element S1 has three holes 8 surrounded by necks 9 projecting from the outer surface of the element S1.

[0033] One of the holes 8 serves as an inlet hole communicating with the passage outlet 5A that brings the lubricant flow from the feed pump. Figure 7 ) is used as an outlet for the lubrication of the seat of the bearing B1. The other two holes 8 are used as outlets, which feed the lubricant flow under pressure to other channels or pipes (one of which is in Figure 4 5B in the figure), the channel or conduit carries the lubricant to other components to be lubricated, such as the components located at the bottom of the unit. Figure 5 , a connection part 11 is provided for connecting the outlet 8 of the distribution box to a channel that guides the lubricant to different users in parallel. The connection part 11 has an outer part 10 that is mounted around the neck 9 of the box S.

[0034] Of course, the configuration of the distribution box S can vary widely with respect to the configuration shown merely by way of example. Similarly, the position of the one or more transmission boxes S within the transmission housing can be selected and optimized based on the specific configuration of the transmission housing, based on the location of the internal components to be lubricated, and based on the need to achieve the greatest possible simplicity of the network of channels that must be formed in the wall of the housing of the transmission unit.

[0035] Also in the case of the example shown, the material constituting the distribution box S is plastic material, but the use of metal materials is not excluded. Of course, the number and size of the holes 8 defining the inlet of each distribution box and at the outlet of each distribution box are determined to vary with specific needs.

[0036] In the example shown, the orifice 8 has an axis orthogonal with respect to the general plane of the distribution box S, but it is also possible to provide the orifice in a side wall of the box, defining a radial inlet and / or radial outlet.

[0037] As is clear from this description, the distribution box S preferably has a substantially flat configuration so that it can be housed in the seats of the rolling bearings of the transmission unit. However, it will be understood that the configuration of the box body is predetermined by the installation location and the available space.

[0038] Of course, while the principle of the invention remains the same, the embodiments may vary widely with respect to what has been described and illustrated purely by way of example, without departing from the scope of the invention as defined in the appended claims.

Claims

1. A gear transmission unit comprising: - a supporting housing (2), - a plurality of shafts (A1, A2, A3) rotatably supported in the support housing (2) by means of corresponding rolling bearings (B1, B2, B3), - a plurality of gears (R1, R2, R3, R4) carried by said shafts (A1, A2, A3) and meshing with each other, - a forced lubrication system (3) for lubricating the rolling bearings (B1, B2, B3) and / or other internal components of the gear transmission unit, the forced lubrication system (3) comprising: - a feed pump (4) for feeding lubricant, and - a plurality of channels (5) formed in the wall of the bearing housing (2) of the gear transmission unit for bringing the lubricant to the vicinity of the internal components to be lubricated, - at least some of the channels (5) are configured for bringing a forced flow of lubricant to one or more channel outlets (5A) adjacent to one or more components to be lubricated, The gear transmission unit is characterized in that it is provided with one or more auxiliary elements in the form of a lubricant distribution box (S), the or each distribution box (S) having a hollow body rigidly connected to the support housing (2) adjacent to a respective channel outlet (5A) supplying a flow of lubricant under pressure, and The hollow body defines an internal lubricant distribution chamber (C) and has an inlet connected to the respective channel outlet (5A) and two or more outlets connected to further pipes or channels (5B) or chambers for supplying lubricant flows under pressure in parallel to the various components to be lubricated within the bearing housing, wherein the distribution box (S) comprises a box element (S1) and a cover (S2) fixed to the box element (S1), and wherein the distribution box (S) has a substantially flat body with two opposing main walls defined by the box element (S1) and the cover (S2), respectively, and wherein the main wall of the box element (S1) has holes (8) defining the outlet and the inlet of the internal lubricant distribution chamber (C), and Therein, the distribution box (S) is accommodated in the seat of the rolling bearing of the gear transmission unit.

2. The gear transmission unit according to claim 1, characterized in that: The box element (S1) comprises a connecting portion (6) provided with holes (7) for engaging screws for fixing the distribution box (S) to the structure of the gear transmission unit.

3. The gear transmission unit according to claim 1 or 2, characterized in that: The gear transmission unit is a gear transmission unit for a motor vehicle.

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