Pressure equalization device for a gearbox housing

Abstract

Pressure equalization device for a gearbox housing (1) comprising: - a calming body (2) to form a calming space (3) which is located in the interior (5) of the gearbox housing (1) and communicates with the adjacent interior (5) of the gearbox housing (1) via an access opening (4) and - a channel device (6) for creating at least a partial section of a pressure equalization channel (7) connecting the calming chamber (3) with the surroundings of the gearbox housing (1), wherein - the calming body (2) is formed by a hollow body segment, - the hollow body segment forms a partition (2a) which faces the interior (5) of the gearbox, - the hollow body segment forms a rear wall (2b) arranged in the vicinity of an inner wall (5a) of the gearbox housing (1), - the hollow body segment forms a first and a second side wall (2c, 2d) extending between the partition (2a) and the back wall (2b), - the channel device (6) is formed by a nozzle section (6a) that projects from the hollow body segment of the calming body (2) and - the hollow body segment is held in the gearbox housing (1) via the nozzle section (6a), characterized in that the nozzle section (6a) rises above the side wall (2d) of the calming body 2 facing a bore (10) in the gearbox housing (1), and the nozzle section (6a) rises on a side of the calming body (2) facing away from the partition wall (2a) above the rear wall (2b) facing the inner wall (5a) of the gearbox housing (1).

Description

Field of invention

[0001] The invention relates to a pressure equalization device for a gearbox housing with a calming element for forming a calming chamber communicating with the interior of the gearbox housing and a channel device for creating a pressure equalization channel through which the calming chamber is connected to the external environment of the gearbox housing.

[0002] DE 28 38 395 C2 discloses a venting device for the interior of a gearbox housing. DE 195 33 140 C1 discloses a venting chamber that is partially integrated with the gearbox housing.

[0003] From DE 10 2015 002 320 A1, a pressure equalization device for a gearbox is known, comprising a bushing section that is inserted into a bore of a gearbox housing and forms a section projecting inwards beyond the inner wall of the gearbox housing. A vent pin is inserted into this bushing section from the outside of the gearbox housing, forming a labyrinth on the inside and supporting a cup section in which a filter material insert is received. The cup section is covered with a cap. Passageways are formed in an intermediate area between the cap and the circumferential area of ​​the cup section, through which pressure equalization between the environment of the gearbox housing and the interior of the gearbox housing is achieved via the filter material insert.

[0004] The subsequently published German patent DE 10 2017 114 889 A1 discloses a pressure equalization device of the type installed in a gearbox housing, which is equipped with a damping element. The damping element communicates with the adjacent interior of the gearbox housing via an access opening and is connected to the environment of the gearbox housing by means of a channel arrangement to create at least a section of a pressure equalization channel. The channel arrangement is formed by a nozzle section that projects from the hollow body segment. Furthermore, the damping element is formed by several interconnected hollow body segments, which form partitions facing the interior of the gearbox housing and have rear walls arranged adjacent to an inner wall of the gearbox housing, as well as side walls extending between the partition and the rear wall.The pressure equalization device is attached to the gearbox housing by means of screw connections, which are formed on the side of the rear wall or one of the side walls.

[0005] A comparable arrangement to the aforementioned pressure equalization device is shown in DE 10 2013 208 788 A1, which, however, has a one-piece calming body.

[0006] Another arrangement comparable to the aforementioned pressure equalization device is shown in the subsequently published DE 10 2017 121 056 A1, in which the calming body is divided into several calming chambers and in which the calming body is held in the gearbox housing via a vent nozzle.

[0007] The CN 10 2017 114 889 A1 designation indicates a vent for a gearbox housing. Object of the invention

[0008] The invention is based on the objective of creating a pressure equalization device that is characterized by a robust and advantageous design from an assembly technology point of view and by which, in particular in a planetary gear drive realized with high component density, pressure equalization with the environment can be achieved reliably and with high oil retention security. Inventive solution

[0009] This problem is solved according to the invention for a pressure equalization device for a gearbox housing according to the subject matter of claim 1.

[0010] The channel assembly is formed by a nozzle section that projects from the hollow body segment of the damping element. The nozzle section is designed to extend beyond a side wall of the damping element facing the bore in the gearbox housing. Preferably, the nozzle section extends beyond the rear wall facing the adjacent gearbox housing area on a side of the damping element furthest from the partition. The pressure equalization device can be inserted radially into the gearbox housing from the inside. Alternatively, the nozzle section can be designed to extend laterally beyond one of the side walls of the hollow body segment.

[0011] This advantageously makes it possible to achieve pressure equalization with a high retention effect even at high operating speeds in gearbox designs with high component packing density, whereby the damping element can be precisely positioned and fixed in the gearbox housing via the nozzle section during gearbox assembly. The concept according to the invention is particularly suitable for use in reduction gearboxes of electromechanical axle drive systems with a high oil fill level.

[0012] According to a particularly preferred embodiment of the invention, the pressure equalization device is constructed such that the nozzle section is manufactured in one piece, i.e., integrally with the hollow body segment. The damping element is preferably made from an injection-molded part of a plastic material.

[0013] The stabilizing body can advantageously be designed such that the partition and / or the back wall have a convexly curved profile with respect to the transmission axis in a section plane radial to a transmission axis.

[0014] The gearbox housing intended to accommodate the calming body can be manufactured in such a way that a bore is provided in the gearbox housing and the nozzle section is then inserted into this bore, at least partially.

[0015] According to a particular aspect of the invention, the nozzle section is preferably fixed in the bore. This fixing can be achieved by friction and / or by positive locking. Furthermore, it is also possible to achieve the fixing by incorporating an adhesive.

[0016] The nozzle section is preferably fixed in place by incorporating sealing rings. These sealing rings can serve for frictional fixation, or they can engage in recesses, particularly annular grooves, thereby providing a force-fit and form-fit securing of the nozzle section in the receiving bore.

[0017] According to a further aspect of the present invention, locking structures can also be advantageously formed on the nozzle section, which then engage in a counter geometry provided by the gearbox housing when the nozzle section is inserted into the bore receiving it.

[0018] The concept according to the invention makes it possible to anchor the calming body in the gearbox housing via its nozzle section, whereby joining techniques that ensure a pressure-tight and loss-proof connection between the calming body and the vent hole in the gearbox housing are shown. Brief description of the characters

[0019] Further details and features of the invention will become apparent from the following description in conjunction with the drawing. It shows: Fig. 1 An axial section view through an upper part of a gearbox, to illustrate the construction of a pressure equalization device according to a first variant according to the invention, in which a nozzle section of a stabilizing body is inserted into a housing bore via a clearance or transition fit using O-rings as sealing and connecting elements, thus positioning and holding the pressure equalization device in the gearbox housing; Fig. 2a and Fig. 2b Illustrations to demonstrate the construction of a pressure equalization device according to the invention in a second variant, in which the connection is effected via two or more locking structures, in particular snap hooks, whereby a sealing ring is again used for sealing; Fig. 3 a further axial section view to illustrate the structure of a pressure equalization device according to the invention in a third variant, in which a pressure-tight and loss-proof connection of the calming body to the housing bore is achieved by an adhesive connection. Detailed description of the characters

[0020] The representation according Fig. Figure 1 shows an embodiment of a first embodiment of a pressure equalization device according to the invention for a gearbox housing 1. The pressure equalization device comprises a damping element 2 for forming a damping chamber 3, which is located in the interior of the gearbox housing 1 and communicates with the adjacent interior 5 of the gearbox housing 1 via an access opening 4. Furthermore, the pressure equalization device also comprises a channel 6 for creating at least a section of a pressure equalization channel 7, which connects the damping chamber 3 with the surroundings 8 of the gearbox housing 1.

[0021] The damping body 2 is formed by a hollow body segment and comprises a partition 2a facing the inner area 5. Furthermore, the damping body 2 comprises a rear wall 2b arranged adjacent to an inner wall 5a of the gearbox housing 1, as well as a first and a second side wall 2c, 2d extending between the partition 2a and the rear wall 2b.

[0022] The channel assembly 6 is formed by a nozzle section 6a that projects from the hollow body segment of the calming body 2. The pressure equalization arrangement is designed such that the hollow body segment of the calming body 2 is positioned in the gearbox housing 1 via the nozzle section 6a and held in the gearbox housing 1.

[0023] The calming element 2 is made of a plastic material, and the nozzle section 6a is formed in one piece, i.e., integrally with the hollow body segment of the calming element 2. As will be explained below in connection with the Fig. 2a and Fig. As will be explained in more detail in section 2b, the calming body 2 is designed as a hollow body structure curved around a gear axis X in a circular segment shape (“banana-like”). Fig. 2b), wherein the inner cross-section of the settling chamber 3 appears as a flat rectangular cross-section in axial section, the width of which measured in the direction of a transmission axis is greater than its height measured radially to the transmission axis. The partition wall 2a and also the rear wall 2b thus exhibit a convex curve with respect to the transmission axis in a section plane radial to a transmission axis.

[0024] The nozzle section 6a forms part of a structural section of the calming body 2 and is designed such that the opening 7b of the pressure equalization channel 7 leading into the calming chamber is as far away as possible from the end section of the nozzle section 6a located in the gearbox housing 1, i.e., it opens into the calming chamber 3 near that side wall 2c which is facing away from the end of the nozzle section 6a located in the gearbox housing 1.

[0025] In the exemplary embodiment according to Fig. In the gearbox housing 1, a bore 10 is formed, and the nozzle section 6a is inserted into this bore, at least partially, with a clearance or transition fit. The nozzle section 6a is designed such that it rises above a side wall 2d of the damping body 2 facing the bore 10 in the gearbox housing 1.

[0026] The nozzle section 6a is fixed in the bore 10. In this embodiment, this fixation is achieved by incorporating sealing rings 11 and 12. The sealing rings 11 and 12 can achieve the fixation purely by friction, or they can engage in annular grooves provided by the nozzle section 6a and the gearbox housing 1, i.e., in the inner area of ​​the bore 10. The fixation can also be achieved, in particular, additionally by positive locking, for example, by temporarily elastically deflectable and then snap-in locking or anchoring structures, as is done in conjunction with Fig. 2a will be explored in greater depth.

[0027] The bore 10 formed in the gearbox housing is machined. It opens into a transverse bore 13 into which a pin element 14 is inserted. This pin element includes retaining structures 14a, which secure it positively in the transverse bore 13. The pin element 14 is sealed in the gearbox housing 1 by a seal 15 and is covered by an elastomer cap 16. The elastomer cap 16 has a pressure equalization slot 16a, which opens a through-cross-section when a pressure difference exists between the environment 8 of the gearbox housing 1 and its interior 5.

[0028] In the embodiment shown here, the transmission forms a reduction gear and / or differential gear of an electromechanical vehicle drive. The damping element 2 is arranged adjacent to a ring gear 17 and, in the transmission's installation position in a motor vehicle, is located in the upper inner region of the transmission housing. The extent of the damping element 2 within the transmission housing 1 is selected such that the access opening 4 of the damping chamber 3 is located downwards in the direction of rotation from the opening 7b of the pressure equalization channel 7. The damping element 2 is designed such that it extends over an angle of 25° to 75° with respect to a transmission axis (central axis of the ring gear).The position of the access opening 4 is chosen so that it points in a direction away from an oil vortex or oil ring running direction, or at least is oriented in such a way that the dynamics of the transmission oil flung up in the normal operation of the transmission does not actively force this oil into the settling chamber 3.

[0029] In the settling chamber 3 itself, further damping structures, such as lamellae or diaphragms, can be arranged, which ensure that the greatest possible separation of oil and oil mist occurs from that gas volume flow which flows over the pressure equalization channel 7 as part of a pressure equalization.

[0030] The in Fig. The first variant shown in Figure 1 is characterized by a nozzle section 6a whose outer diameter is dimensioned such that it forms a clearance or transition fit with the bore 10. This allows the nozzle section 6a of the damping body 2 to be inserted into the bore 10 (e.g., by manual assembly). Furthermore, one or more grooves 11a, 12a, designed as O-ring grooves, are provided at the nozzle end. Sealing rings 11, 12, designed as O-rings, are inserted into these grooves, sealing the connection and simultaneously securing the nozzle section 6a of the damping body 2 in the bore 10.

[0031] The representations according to Fig. Figure 2a shows an embodiment of a second embodiment of a pressure equalization device according to the invention for a gearbox housing 1. The pressure equalization device again comprises a stabilizing element 2 for forming a stabilizing chamber 3, which is located in the interior of the gearbox housing 1 and communicates with the adjacent interior 5 of the gearbox housing 1 via an access opening 4. The pressure equalization device also comprises a channel 6 for creating at least a section of a pressure equalization channel 7, which connects the stabilizing chamber 3 with the surroundings 8 of the gearbox housing 1.

[0032] The damping body 2 is also formed here by a hollow body segment and comprises a partition 2a facing the inner area 5. Furthermore, the damping body 2 comprises a rear wall 2b arranged adjacent to an inner wall 5a of the gearbox housing 1, as well as a first and a second side wall 2c, 2d extending between the partition 2a and the rear wall 2b.

[0033] The channel assembly 6 is formed by a nozzle section 6a that projects from the calming body 2. This differs from the variant according to... Fig. In this case, the nozzle section 6a is designed such that, on a side facing away from the partition wall 2a, the nozzle section 6a rises substantially perpendicularly above the rear wall 2b facing the adjacent inner area of ​​the gearbox housing 5. The nozzle section 6a is provided with locking structures 6b that engage with a counter geometry 1a provided by the gearbox housing 1.

[0034] In this embodiment, at least one sealing ring 12 is also provided, which seals the joint between the outer wall of the nozzle section 6a and the inner wall of the bore 10. A pin element 14 is inserted into a bore section, which here is implemented as a direct extension of the channel 7. This pin element includes retaining structures 14a, which secure it positively in the bore 10. The pin element 14 is sealed in the gearbox housing 1 by a seal 15 and is covered by an elastomer cap 16. A pressure equalization slot 16a is formed in the elastomer cap 16, which opens a passage cross-section when a pressure difference exists between the environment 8 of the gearbox housing 1 and its interior 5.

[0035] The representation according Fig. Figure 2b illustrates, in the form of a perspective view of individual parts, the structure of the calming body 2 as it is used in the embodiment according to Fig. 2a is used. The calming element 2 is made of a plastic material and the nozzle section 6a is formed in one piece, i.e. integrally with the hollow body segment of the calming element 2. The calming element 2 is designed as a hollow body structure curved around a gear axis X in a circular segment shape (“banana-like”) and exhibits the following in axial section Fig. 2a shows a flat, rectangular internal cross-section, the width of which, measured in the direction of a transmission axis, is greater than its height, measured radially to the transmission axis. The partition 2a and also the rear wall 2b thus exhibit a convex curve with respect to the transmission axis X in a section plane radial to a transmission axis. The hollow body structure projects longitudinally beyond the connection area of ​​the nozzle section 6a on one side facing away from the access opening 4. In this projecting area, a pressure equalization window 2e is formed in the side wall 2c, which allows for equalization of the static pressure in the settling chamber 3 along its entire length.

[0036] The in the Fig. 2a and Fig. Figure 2b illustrates the second variant based on the fastening of the damping element 2 using snap hooks 6d. The snap connection can be designed such that two or more levers 6c with snap hooks 6d are positioned opposite each other. Adjacent to the snap hooks 6d is a sealing surface for a sealing ring 12 (e.g., an O-ring), which seals the connection. This creates a pressure-tight and captive connection between the damping element 2 and the vent bore 10 in the gearbox housing 1. Key basic elements of the connection are therefore the snap hooks 6d for fastening, a sealing surface (for a sealing ring, e.g., an O-ring), and a collar 6e, which serves as a stop for axial positioning in the bore 10.

[0037] For the presentation according to Fig. 3. The statements regarding Fig. 1. In essence. Deviating from the variant according to Fig. 1. Here, on the nozzle section 6a, the grooves 11a and 12a are designed as adhesive grooves, which are filled with adhesive that forms an adhesive bond with the gearbox housing 1. This concept can also be used in conjunction with the [reference to be added]. Fig. 1 sealing rings are used.

[0038] The bore 10, designed to receive the nozzle section 6a, and the nozzle section 6a itself are dimensionally matched such that the nozzle section 6a fits snugly in the bore 10. The gap is filled by the adhesive. This adhesive method can also be implemented in conjunction with snap-fit ​​structures, as shown in the exemplary embodiment shown in [reference to illustration]. Fig. 2a were used to anchor the nozzle section 6a in the gearbox housing 1.

[0039] The third variant for attaching the calming element 2 is similar to the first variant. It is suitable as an alternative or supplementary variant to the embodiments according to the Fig. 1 and Fig. 2a. The outer diameter of the nozzle section 6a is again designed as a clearance or transition fit for manual assembly. Also located at the end of the nozzle section 6a are one or more grooves 11a, 12a, which, however, have a shallower depth than in variant 1. Fig. 1. Adhesive can be applied to these grooves 11a, 12a, thereby bonding the damping element 2 in the housing bore 10 during assembly. Thus, the adhesive in the grooves 11a, 12a not only fixes the component section 6a of the damping element 2 in the bore 10, but also ensures a pressure-tight connection to the housing 1. Reference sign 1 Gearbox housing 1a Opposite geometry 2 calming bodies 2a Partition wall of the calming body 2b Back wall of the calming body 2c side wall 2D side wall 2e Pressure equalization window 3 Calming Room 4 Access opening 5 Interior of the gearbox housing 5a Inner wall of the gearbox housing 6-channel setup 6a Branch section of the canal system 6b Raster structure 6c lever 6d Snap hook 6th Bund 7 Pressure equalization channel 7b Opening of the pressure equalization channel 8 Environment 10 Drilling 11 Sealing ring 11a Nut 12 Sealing ring 12a Nut 13 Cross bore 14 pin element 14a Holding structures of the pin element 15 Seal 16 Elastomer cap 16a Pressure equalization slot X Gear axle

Claims

[1] Pressure equalization device for a gearbox housing (1) comprising: - a calming body (2) to form a calming space (3) which is located in the interior (5) of the gearbox housing (1) and communicates with the adjacent interior (5) of the gearbox housing (1) via an access opening (4) and - a channel device (6) for creating at least a partial section of a pressure equalization channel (7) connecting the calming chamber (3) with the surroundings of the gearbox housing (1), wherein - the calming body (2) is formed by a hollow body segment, - the hollow body segment forms a partition (2a) which faces the interior (5) of the gearbox, - the hollow body segment forms a rear wall (2b) arranged in the vicinity of an inner wall (5a) of the gearbox housing (1), - the hollow body segment forms a first and a second side wall (2c, 2d) extending between the partition (2a) and the back wall (2b), - the channel device (6) is formed by a nozzle section (6a) that projects from the hollow body segment of the calming body (2) and - the hollow body segment is held in the gearbox housing (1) via the nozzle section (6a), characterized by , that the nozzle section (6a) rises above the side wall (2d) of the calming body 2 facing a bore (10) in the gearbox housing (1), and that the nozzle section (6a) rises on a side of the calming body (2) facing away from the partition wall (2a) above the rear wall (2b) facing the inner wall (5a) of the gearbox housing (1). [2] Pressure equalization device according to claim 1, characterized by , that the nozzle section (6a) is formed integrally with the hollow body segment. [3] Pressure equalization device according to claim 1 or 2, characterized by , that the partition (2a) and / or the rear wall (2b) have a convexly curved profile with respect to the gear axis (X) in a section plane radial to a gear axis (X). [4] Pressure equalization device according to at least one of claims 1 to 3, characterized by , that a bore (10) is formed in the gearbox housing (1) and that the nozzle section (6a) is inserted at least partially into this bore (10). [5] Pressure equalization device according to at least one of claims 1 to 4, characterized by , that the nozzle section (6a) is fixed in the bore (10). [6] Pressure equalization device according to at least one of claims 1 to 5, characterized by that the fixation is achieved by friction and / or form-fitting means and / or that the fixation is achieved by incorporating an adhesive. [7] Pressure equalization device according to at least one of claims 1 to 6, characterized by , that the fixing of the nozzle section (6a) is accomplished by incorporating sealing rings (11, 12). [8] Pressure equalization device according to at least one of claims 1 to 7, characterized by , that the nozzle section (6a) is provided with locking structures (6b) which engage in a counter geometry (1a) provided by the gearbox housing (1).

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