Ventilation structure

Abstract

Provided is a ventilation structure that suppresses discharge of oil from a ventilation chamber to the atmosphere. The ventilation structure is provided in a housing having a first housing member and a second housing member that form a housing chamber in a state in which the first housing member and the second housing member abut against each other. The ventilation structure is provided with: a ventilation chamber in which a first inner wall part, which is an inner wall part of the first case member, and a second inner wall part, which is an inner wall part of the second case member, are brought into contact with each other to form an enclosed hollow chamber, and in which a first communication part that communicates with the housing chamber and a second communication part that communicates with the atmosphere are provided; and a front chamber which is adjacent to the ventilation chamber between the housing chamber and the ventilation chamber, and which forms an enclosed empty chamber by abutting the first inner wall portion and the second inner wall portion.

Description

Technical Field

[0001] The invention relates to a ventilation structure. Background Art

[0002] Patent Document 1 discloses a breather chamber formed by contact between inner walls of a torque converter housing and a transmission case. The breather chamber communicates with the interior of the housing via an upper communication portion and a lower communication portion, respectively, and communicates with the atmosphere via an atmosphere communication hole.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 10-205609

[0006] Problems to be solved by the invention

[0007] Since the inner wall of the box body does not constitute a partition between the storage chamber of the box body and the atmosphere, the butting surfaces of the inner wall parts of the two box body parts are not sealed by the sealing member, and are not completely sealed. Therefore, a gap may be formed between the butting surfaces due to dimensional error, assembly error, deformation, etc. As a result, oil may penetrate from the storage chamber of the box body through such a gap into the ventilation chamber formed by butting the inner wall parts of the two box body parts together, and may be discharged to the atmosphere through the connecting part with the atmosphere provided in the ventilation chamber. Summary of the invention

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to suppress the discharge of oil from the breather chamber to the atmosphere.

[0009] Technical solutions to solve problems

[0010] A ventilation structure of one embodiment of the present invention is provided in a box body having a first box body part and a second box body part that form a storage chamber in a state of being butted against each other. The ventilation structure comprises: a ventilation chamber that is formed as an enclosed empty chamber by butting against a first inner wall part as an inner wall part of the first box body part and a second inner wall part as an inner wall part of the second box body part, and is provided with a first connecting part that communicates with the storage chamber and a second connecting part that communicates with the atmosphere; and a front chamber (front guard chamber) that is adjacent to the ventilation chamber between the storage chamber and the ventilation chamber, and is formed as an enclosed empty chamber by butting against the first inner wall part and the second inner wall part.

[0011] Effects of the Invention

[0012] According to this method, since a front chamber adjacent to the ventilation chamber is provided between the storage chamber and the ventilation chamber, the front chamber plays a role in suppressing the infiltration of oil into the ventilation chamber, and oil is difficult to infiltrate into the ventilation chamber. In addition, even if oil infiltrates into the ventilation chamber, the infiltrated oil can be discharged to the storage chamber via the first connecting portion. Therefore, the discharge of oil from the ventilation chamber to the atmosphere can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the power transmission device.

[0014] Figure 2 This is a diagram of the housing body viewed from the shell side in an axial direction.

[0015] Figure 3 This is a diagram of the housing viewed from the housing body side in an axial view.

[0016] Figure 4 This is an enlarged view of the ventilation structure provided in the main body of the box.

[0017] Figure 5 This is an enlarged view of a ventilation structure provided in a portion of the housing.

[0018] Figure 6 This is an illustration of the ventilation structure.

[0019] Figure 7 It is a diagram showing a first modified example of the ventilation structure.

[0020] Figure 8 It is a diagram showing a second modification of the ventilation structure. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0022] Figure 1 is a schematic diagram of the structure of the power transmission device 100 according to the present embodiment. Figure 1 In FIG. 4 , the rotating electric machine 40 is indicated by a double-dashed line. Figure 1 As shown, the power transmission device 100 includes a housing 10, a speed reduction mechanism 20, and a differential gear 30. The power transmission device 100 is mounted on a vehicle. The vehicle is an electric vehicle using a rotary motor 40 as a power source. The power transmission device 100 transmits power from the rotary motor 40 to the drive wheels. The power transmission device 100 can also transmit power from the drive wheels to the rotary motor 40.

[0023] The housing 10 has a housing body 11 as a first housing member and a housing 12 as a second housing member. The housing body 11 is disposed on one axial side (right side in the figure), and the housing 12 is disposed on the other axial side (left side in the figure). The axial direction is the extension direction of the shaft (power transmission shaft) of the power transmission device 100, and the extension directions of the first shaft 21, the second shaft 22, and the third shaft 33 described later correspond to the axial direction, respectively.

[0024] The box body 11 has a storage portion 11a, and the shell 12 has a storage portion 12a. The storage portion 11a opens toward the left side of the figure, and the storage portion 12a opens toward the right side of the figure. The shell 12 is provided on the box body 11, and the opening of the storage portion 11a is blocked by the opening of the storage portion 12a. The space formed by the storage portion 11a and the storage portion 12a constitutes a storage chamber S of the box body 10. The storage chamber S is formed by the box body 11 and the shell 12 being butted against each other.

[0025] The case body 11 further includes a cylindrical portion 11b. The cylindrical portion 11b is provided on the right side of the storage portion 11a in the figure. A rotary motor 40 is arranged in the cylindrical portion 11b. Therefore, the power transmission device 100 can also be understood as a structure further including the rotary motor 40. The rotary motor 40 is fixed to the inner periphery of the cylindrical portion 11b.

[0026] The rotary electric machine 40 includes a rotor 41, a stator 42, a rotary shaft 43, and a motor case 44. The rotor 41 is housed in the stator 42, and the stator 42 is fixed to the inner periphery of the cylindrical portion 11b via the motor case 44. The rotary shaft 43 protrudes into the housing portion 11a via a through hole that penetrates the wall between the housing portion 11a and the cylindrical portion 11b, and a sealing member is provided between the through hole and the rotary shaft 43. Therefore, the inside of the cylindrical portion 11b, which is a space for arranging the rotary electric machine 40, is separated from the housing chamber S, which is a space for arranging the speed reduction mechanism 20 and the differential gear 30, and does not constitute the housing chamber S.

[0027] The reduction mechanism 20 is a gear mechanism having a first shaft 21 and a second shaft 22. The first shaft 21 is connected to the rotating motor 40. The first shaft 21 is connected to the rotating motor 40 in a manner capable of transmitting power. The connection may also be a connection via other structures (such as a clutch or other gear mechanisms). In the present embodiment, the first shaft 21 is directly connected to the rotating motor 40 by being directly connected to the rotating shaft 43. The direct connection between the first shaft 21 and the rotating motor 40 means that the first shaft 21 is arranged on the axis of the rotating motor 40 and is directly connected to the rotating motor 40 without passing through a clutch or other gear mechanisms.

[0028] The first shaft 21 has a first gear portion 211. The first gear portion 211 is composed of a first gear G1. The first gear portion 211 is formed integrally with the first shaft 21, and outputs power from the rotating motor 40. The first shaft 21 is supported by the housing body 11 on one axial side by a bearing 51 and supported by the housing 12 on the other axial side by a bearing 52, thereby being supported by the housing 10. A parking gear 212 is also provided on the first shaft 21 between the first gear portion 211 and the bearing 51. The first shaft 21 constitutes the first shaft of the power transmission device 100.

[0029] The second shaft 22 has a second gear portion 221. The second gear portion 221 is composed of a second gear G2 and a third gear G3. The second gear G2 is pressed into the second shaft 22 to form an integral body, and the third gear G3 is formed integrally with the second shaft 22. The third gear G3 is arranged on the right side of the figure, that is, on the side close to the rotating motor 40, than the second gear G2. The second gear G2 meshes with the first gear G1, and power is input from the first gear G1 to the second gear G2.

[0030] The power input to the second gear G2 is output from the third gear G3. Therefore, the second gear portion 221 receives power from the first gear G1 and outputs the input power. The number of teeth of the second gear G2 is set to be greater than that of the first gear G1, and together with the first gear G1, it constitutes a first reduction gear stage. The second shaft 22 is supported by the housing 10 by a bearing 53 on one axial side and by a bearing 54 on the housing 12 on the other axial end side. The second shaft 22 constitutes the second shaft of the power transmission device 100.

[0031] The differential gear 30 is a differential gear mechanism, and includes a differential case 31, a fourth gear G4 as a final drive gear, and a differential portion 32. The differential case 31 is axially supported on the case body 10 by being supported by a bearing 55 provided on the case body 11 and a bearing 56 provided on the housing 12. The fourth gear G4 is coaxially fixed to the outer wall portion of the differential case 31. The fourth gear G4 meshes with the third gear G3, and power is input from the third gear G3 to the fourth gear G4. The differential case 31 and the fourth gear G4 together constitute the third shaft 33 of the power transmission device 100. The fourth gear G4 constitutes the third gear portion 331 of the third shaft 33.

[0032] The differential case 31 accommodates the differential unit 32, and the differential unit 32 distributes the power input to the differential case 31 via the fourth gear G4 to the driving wheels in the left and right directions of the vehicle and outputs it. Therefore, the fourth gear G4 as the third gear unit 331 is connected to the driving wheels via the differential case 31 and the differential unit 32, and transmits the input power to the driving wheels.

[0033] The fourth gear G4 has a larger number of teeth than the third gear G3 and forms a second reduction gear stage together with the third gear G3. Therefore, in the power transmission device 100, two-stage reduction is performed by the first gear G1 and the second gear G2, and the third gear G3 and the fourth gear G4.

[0034] An oil storage tank is formed at the lower part of the housing 10, and the fourth gear G4 is immersed in the oil storage tank. The fourth gear G4 stirs up the oil in the oil storage tank to circulate the oil in the housing 10. The fourth gear G4 is set at a height such that at least a part of it is immersed in the oil storage tank regardless of whether the device is driven or stopped.

[0035] The power transmission device 100 is a three-axis power transmission device in which a total of three axes, namely the first axis 21, the second axis 22 and the third axis 33, are arranged as power transmission axes in the storage chamber S. The axes of the power transmission device 100 are composed of a plurality of axes sequentially connected in radial direction by meshing of gear portions.

[0036] Figure 2 This is a diagram of the housing body 11 as viewed from the case 12 side in the axial direction. Figure 3 1 is a diagram showing the housing 12 from the side of the housing body 11 in an axial view. Figure 2 , Figure 3 In FIG. 1 , the first shaft 21, the second shaft 22, and the third shaft 33 are schematically indicated by arrows indicating the rotation directions. Figure 2 , Figure 3 In FIG. 1 , the third gear portion 331 (i.e., the fourth gear G4) is also indicated by a two-dot chain line. Figure 2 , Figure 3 , the up-down direction of the figure corresponds to the direction of gravity, and the left-right direction of the figure corresponds to the front-rear direction of the vehicle.

[0037] The housing 10 has a ventilation structure 10a. The ventilation structure 10a is provided in the housing 10, communicates with the atmosphere, and separates the air and oil in the storage chamber S. The housing 10 is formed as a space surrounded by the outer wall portion of the housing 10 (the wall portion constituting the outer wall of the housing 10), and the storage chamber S is divided in the housing 10 as a space for arranging the speed reduction mechanism 20 and the differential gear 30.

[0038] The ventilation structure 10a is disposed above and near the third axis 33. Above and below refer to configurations that appear to overlap in the direction of gravity when viewed from a specified direction including axial or radial observation. For example, when a first element overlaps with a second element in the direction of gravity in axial observation, if the first element is located higher than the second element, the first element is located above the second element. In this case, in radial observation, the first element and the second element may overlap or may be offset.

[0039] The ventilation structure 10a is provided above the third shaft 33 because it has a portion that overlaps with the third shaft 33 in the gravity direction at a position higher than the third shaft 33, that is, overlaps in the gravity direction. The ventilation structure 10a is provided within a range that does not protrude from the fourth gear G4 in the left-right direction of the figure. The ventilation structure 10a is provided at a position higher than the fourth gear G4 of the third shaft 33 in the left-right direction of the figure, and is provided at a position higher than the fourth gear G4 as a whole.

[0040] Figure 4 It is an enlarged view of the ventilation structure 10a provided on the side of the housing body 11. Figure 5 FIG. 1 is an enlarged view of the ventilation structure 10a provided on the side of the housing 12. Figure 4 , Figure 5 In FIG. 1 , the third gear portion 331 (i.e., the fourth gear G4) is also indicated by a two-dot chain line. Figure 4 , Figure 5 , the up-down direction of the figure corresponds to the direction of gravity, and the left-right direction of the figure corresponds to the front-rear direction of the vehicle.

[0041] like Figure 4 , Figure 5 As shown, the ventilation structure 10a has a ventilation chamber R1 and a front chamber (front guard chamber) R2. In the ventilation structure 10a, the ventilation chamber R1 is divided into an upper side in the direction of gravity, and the front chamber R2 is divided into a lower side in the direction of gravity. The front chamber R2 arranged in this way is adjacent to the ventilation chamber R1 between the ventilation chamber R1 and the storage chamber S. The front chamber R2 is arranged on the inner side of the housing 10 relative to the ventilation chamber R1 by being arranged between the ventilation chamber R1 and the fourth gear G4 arranged in the storage chamber S. The front chamber R2 is adjacent to the storage chamber S on the opposite side (the lower side of the figure) to the side adjacent to the ventilation chamber R1.

[0042] The ventilation structure 10a includes inner walls W11 and W21 and inner walls W12 and W22. The ventilation chamber R1 and the front chamber R2 are partitioned vertically in the gravity direction by the inner walls W11 and W21, and are adjacent to each other via the inner walls W11 and W21.

[0043] The inner wall portion W11 and the inner wall portion W21 are at one end in the left-right direction of the figure ( Figure 4 The right side and Figure 5 The inner wall portion W12 is connected to the outer wall portion of the box body 10. The inner wall portion W12 is connected to the other end of the inner wall portion W11 in the left and right direction of the figure ( Figure 4 The inner wall portion W22 is connected to the inner wall portion W21 at the other end in the left-right direction of the figure ( Figure 5 The inner wall portion W12 extends upward from the connection portion with the inner wall portion W11 and is connected to the outer wall portion of the box body 10, and the inner wall portion W22 extends upward from the connection portion with the inner wall portion W21 and is connected to the outer wall portion of the box body 10.

[0044] The ventilation chamber R1 is formed into an enclosed empty chamber by making the inner wall portion W11 and the inner wall portion W21 butt with the inner wall portion W12 and the inner wall portion W22, that is, by making them abut. The inner wall portion W11 and the inner wall portion W21 form a partition wall that separates the ventilation chamber R1 from the front chamber R2 when the box body 11 and the shell 12 are butt-jointed with each other. The inner wall portion W12 and the inner wall portion W22 form a partition wall that separates the ventilation chamber R1 from the storage chamber S when the box body 11 and the shell 12 are butt-jointed with each other.

[0045] In addition to the inner wall portions W11 and W12 and the inner wall portions W21 and W22, the ventilation chamber R1 is also surrounded by the outer wall portion of the housing 10 to form an empty chamber. The wall portion of the ventilation chamber R1 in the vehicle left-right direction (the axial direction of the fourth gear G4) is formed by the outer wall portion of the housing 10. The outer wall portion of the housing 10 constituting the ventilation chamber R1 constitutes a partition wall that separates the ventilation chamber R1 from the atmosphere.

[0046] The inner wall portion W11 and the inner wall portion W21 and the inner wall portion W12 and the inner wall portion W22 constitute a ventilation forming portion that forms the ventilation chamber R1. Therefore, in other words, the ventilation chamber R1 forms an empty chamber surrounded by the ventilation forming portion. The ventilation structure 10a having the ventilation chamber R1 is synonymous with having the ventilation forming portion, and the same is true for the front chamber R2 and the storage chamber S. The ventilation forming portion, the front chamber forming portion that forms the front chamber R2, and the storage chamber forming portion that forms the storage chamber S can be formed by the wall portion of the box body 10.

[0047] The ventilation structure 10a also has an inner wall portion W13, an inner wall portion W23, and an inner wall portion W14. The inner wall portion W13 and the inner wall portion W23 constitute the lower wall portion of the ventilation structure 10a, and constitute the lower wall portion of the front chamber R2. The lower wall portion of the front chamber R2 constitutes an opposing wall portion that faces the tooth surface of the fourth gear G4 that stirs up the oil. The tooth surface of the fourth gear G4 is the outer peripheral surface of the fourth gear G4 (the surface formed on the outer periphery of the fourth gear G4 by the gear teeth of the fourth gear G4).

[0048] The inner wall portion W13 and the inner wall portion W23 have a shape that is curved along the third axis 33 together with the inner wall portion W11 and the inner wall portion W21. The curved shape is a shape along the fourth gear G4 that is the maximum outer diameter portion of the third axis 33. The ventilation structure 10a is provided with such a curved shape relative to the third axis 33, for example, and is thus provided as close to the third axis 33 as possible, and is thereby provided near the third axis 33.

[0049] The inner wall portion W13 and the inner wall portion W23 are at one end in the left-right direction of the figure ( Figure 4 The right side and Figure 5 The inner wall portion W14 is connected to the outer wall portion of the box body 10. The inner wall portion W14 is connected to the other end of the inner wall portion W13 in the left and right direction of the figure ( Figure 4The inner wall portion W14 extends upward from the connection portion with the inner wall portion W13 and is connected to the inner wall portion W11. The inner wall portion W14 is connected to the inner wall portion W11 and the inner wall portion W12 by being connected to the connection portions with the inner wall portion W11 and the inner wall portion W12.

[0050] The inner wall portion W23 is on the other end side ( Figure 5 The discharge hole 10aa of the front chamber R2 is formed between the inner wall portion W21 and the inner wall portion W21. The discharge hole 10aa is provided on the housing 12 and is formed by not connecting the other ends of the inner wall portion W21 and the inner wall portion W23 to each other. The discharge hole 10aa formed in this way is provided in the front chamber R2 to connect the front chamber R2 and the storage chamber S. The discharge hole 10aa can also be formed by, for example, connecting the other ends of the inner wall portion W21 and the inner wall portion W23 to each other at the inner wall portion and providing it at the inner wall portion.

[0051] The discharge hole 10aa opens to the storage chamber S at a position not facing the tooth surface of the fourth gear G4. Therefore, the discharge hole 10aa is not provided on the inner wall portion W23 facing the tooth surface of the fourth gear G4. The discharge hole 10aa may also be provided on the box body 11 (for example, the inner wall portion W14). The fourth gear G4 is equivalent to a gear.

[0052] The front chamber R2 is a hollow chamber surrounded by the inner wall W13 and the inner wall W23. The inner wall W13 and the inner wall W23 form a partition wall that separates the front chamber R2 and the storage chamber S when the box body 11 and the shell 12 are butted against each other.

[0053] In addition to the inner wall portion W13 and the inner wall portion W23, the front chamber R2 is also surrounded by the inner wall portion W11, the inner wall portion W21, the inner wall portion W14, and the outer wall portion of the box body 10 to form an empty chamber. The inner wall portion W14 forms a partition wall that distinguishes the front chamber R2 from the storage chamber S on the side of the box body 11 when the box body 11 and the shell 12 are docked with each other. The wall portion of the front chamber R2 in the left-right direction of the vehicle (the axial direction of the fourth gear G4) is formed by the outer wall portion of the box body 10. The outer wall portion of the box body 10 that constitutes the front chamber R2 constitutes a partition wall that distinguishes the front chamber R2 from the atmosphere.

[0054] The inner wall portion W13 and the inner wall portion W23 together with the inner wall portion W11 and the inner wall portion W21, the inner wall portion W14, and the outer wall portion of the box body 10 constitute a front chamber forming portion that forms the front chamber R2. Therefore, the front chamber R2 is formed as an empty chamber surrounded by the front chamber forming portion. By providing the discharge hole 10aa, the front chamber R2 becomes a structure surrounded by the front chamber forming portion and also communicated with the storage chamber S through the discharge hole 10aa.

[0055] The ventilation structure 10a also has an inner wall portion W15, an inner wall portion W16 and an inner wall portion W24. The inner wall portion W15, the inner wall portion W16 and the inner wall portion W24 are arranged in the ventilation chamber R1. The ventilation chamber R1 is constructed as a labyrinth chamber, and air and oil are separated by circulating air in the labyrinth passage. The labyrinth passage is formed by a plurality of walls, namely, the inner wall portion W15, the inner wall portion W16 and the inner wall portion W24, which are arranged alternately along the left and right directions of the figure on the box body 11 side and the shell 12 side of the ventilation chamber R1. The inner wall portion W15, the inner wall portion W24 and the inner wall portion W16 are arranged in sequence along the left and right directions of the figure. From the inner wall portion W11 to the inner wall portion W16 is equivalent to the first inner wall portion, and from the inner wall portion W21 to the inner wall portion W24 is equivalent to the second inner wall portion.

[0056] Next, use Figure 6 The ventilation structure 10a will be further described.

[0057] Figure 6 1 is an explanatory diagram of the ventilation structure 10a. Figure 6 , the ventilation structure 10 a is schematically shown together with the fourth gear G4 as the third gear portion 331 . Figure 6 is a diagram of the ventilation structure 10a viewed from the box body 11 side in the axial direction, corresponding to Figure 3 and Figure 5 Axial observation. Figure 6 , the up-down direction of the figure corresponds to the direction of gravity, and the left-right direction of the figure corresponds to the front-rear direction of the vehicle.

[0058] The ventilation structure 10a also has a connecting hole 10ab and a vent pipe 10ac. The connecting hole 10ab connects the ventilation chamber R1 and the storage chamber S, and the vent pipe 10ac connects the ventilation chamber R1 and the atmosphere. Therefore, the connecting hole 10ab is provided in the ventilation chamber R1 as a connecting portion connected to the storage chamber S, and the vent pipe 10ac is provided as a connecting portion connected to the atmosphere. The connecting hole 10ab is equivalent to the first connecting portion, and the vent pipe 10ac is equivalent to the second connecting portion.

[0059] The communication hole 10ab and the vent pipe 10ac are both provided in the housing 12. The communication hole 10ab may also be provided in the housing body 11, and the same applies to the vent pipe 10ac. The vent pipe 10ac penetrates the outer wall of the housing 10 from above the vent chamber R1 to connect the vent chamber R1 with the atmosphere.

[0060] The connecting hole 10ab is provided to bypass the front chamber R2. Therefore, the connecting hole 10ab does not open in the front chamber R2. The connecting hole 10ab extends from the ventilation chamber R1 in the wall portion of the box body 10, and opens to the storage chamber S between the inner wall portion W23 and the fourth gear G4. For the connecting hole 10ab, the extension shape and the opening position can be set so that the oil stirred up by the fourth gear G4 is difficult to penetrate into the ventilation chamber R1 through the connecting hole 10ab.

[0061] For example, the connecting hole 10ab extends in a straight line, and the opening to the storage chamber S is arranged on the right side of the figure, that is, the rear side of the fourth gear G4 in the upper half in the rotation direction, than the opening to the ventilation chamber R1. The opening of the connecting hole 10ab to the storage chamber S is arranged rearward of the upper end of the fourth gear G4 in the rotation direction of the fourth gear G4 in the upper half. The connecting hole 10ab may also be curved.

[0062] The inner wall portion W21 is in metallic contact with the inner wall portion W11 when it is butted against the inner wall portion W11 on the side of the box body 11, and no sealing component is particularly provided between the inner wall portion W21 and the inner wall portion W11. That is, the butt joint surface between the inner wall portion W21 and the inner wall portion W11 is not completely sealed, and a gap is formed between the butt joint surfaces due to dimensional error, assembly error, deformation, etc.

[0063] Therefore, the ventilation structure 10a is configured such that air flows from the front chamber R2 to the breather chamber R1 through a gap formed at the butting surface between the inner wall portion W21 and the inner wall portion W11, and the breather chamber R1 and the front chamber R2 are not connected via a hole or the like connecting them.

[0064] The same gap is also formed at the interface between the inner wall portion W23 and the inner wall portion W13. Therefore, the oil stirred up from the storage chamber S by the fourth gear G4 penetrates into the front chamber R2 through the gap formed at the interface. The arrows shown together with the throttle on the inner wall portion W23 schematically represent the oil penetrating into the front chamber R2 in this way. Figure 6 For the sake of convenience, Figure 3 and Figure 5 In comparison, the ventilation structure 10a is shown larger, but Figure 3 and Figure 5 As shown, the same is true when a ventilation structure 10a is provided.

[0065] The oil immersed in the front chamber R2 is mainly discharged from the front chamber R2 to the storage chamber S through the discharge hole 10aa. That is, because the discharge hole 10aa is provided in the front chamber R2, even if the oil accumulates in the front chamber R2, the accumulated oil is mainly discharged from the front chamber R2 to the storage chamber S through the discharge hole 10aa. The discharge hole 10aa also plays a role in suppressing the increase in the internal pressure of the front chamber R2. Therefore, in the ventilation structure 10a, the oil immersed in the ventilation chamber R1 from the front chamber R2 through the gap between the inner wall portion W21 and the inner wall portion W11 is reduced. As a result, it is possible to suppress the oil from being discharged from the ventilation chamber R1 to the atmosphere through the ventilation pipe 10ac.

[0066] The discharge hole 10aa opens to the storage chamber S at a position not facing the tooth surface of the fourth gear G4 of the differential gear 30. Therefore, the oil stirred up by the fourth gear G4 is unlikely to penetrate into the front chamber R2 through the discharge hole 10aa. As a result, since the oil penetrating into the front chamber R2 is suppressed, the discharge of oil to the atmosphere due to the oil penetrating from the discharge hole 10aa is also suppressed.

[0067] In the breather chamber R1, air is separated from oil by flowing through the labyrinth passage. Air is discharged from the breather chamber R1 to the atmosphere through the breather pipe 10ac, and oil is discharged to the storage chamber S through the communication hole 10ab. Therefore, discharge of oil to the atmosphere is also suppressed by the communication hole 10ab.

[0068] The communication hole 10ab is provided so that the oil stirred up by the fourth gear G4 is unlikely to penetrate into the breather chamber R1 through the communication hole 10ab. Therefore, the oil penetrating from the communication hole 10ab is prevented from promoting the discharge of oil into the atmosphere.

[0069] Next, the main effects of this embodiment will be described.

[0070] (1) The ventilation structure 10a is provided in a box body 10 having a box body main body 11 and a shell 12 which are butted together to form a storage chamber S. The ventilation structure 10a has: a ventilation chamber R1 which is an enclosed empty chamber formed by butting the inner wall portions W11 and W12 with the inner wall portions W21 and W22, and is provided with a connecting hole 10ab communicating with the storage chamber S and a ventilation pipe 10ac communicating with the atmosphere; and a front chamber R2 which is adjacent to the ventilation chamber R1 between the storage chamber S and the ventilation chamber R1 and is an enclosed empty chamber formed by butting the inner wall portions W13 and W23.

[0071] According to such a structure, since the front chamber R2 adjacent to the breather chamber R1 is provided between the storage chamber S and the breather chamber R1, the front chamber R2 plays a role in suppressing the infiltration of oil into the breather chamber R1, and the oil is difficult to infiltrate into the breather chamber R1. In addition, even if the oil infiltrates into the breather chamber R1, the infiltrated oil can be discharged to the storage chamber S through the connecting hole 10ab. Therefore, the discharge of oil from the breather chamber R1 to the atmosphere can be suppressed.

[0072] (2) In the ventilation structure 10a, a discharge hole 10aa is provided in the front chamber R2 for discharging the oil immersed in the front chamber R2 to the storage chamber S. According to such a structure, the oil accumulated in the front chamber R2 can be discharged, and the increase in the internal pressure of the front chamber R2 can also be suppressed. Therefore, the oil that penetrates into the ventilation chamber R1 from the front chamber R2 through the gap between the inner wall portion W21 and the inner wall portion W11 can be reduced, thereby suppressing the discharge of oil from the ventilation chamber R1 to the atmosphere.

[0073] (3) In the ventilation structure 10a, the differential gear 30 as a gear mechanism is accommodated in the storage chamber S. The discharge hole 10aa opens to the storage chamber S at a position that is not opposite to the tooth surface of the fourth gear G4 of the differential gear 30. According to such a structure, it is possible to suppress the oil stirred up by the fourth gear G4 from penetrating into the front chamber R2 through the discharge hole 10aa. As a result, the oil penetrating into the front chamber R2 is suppressed. Therefore, by suppressing the situation in which the discharge of oil to the atmosphere is promoted by the oil penetrating from the discharge hole 10aa, the discharge of oil from the ventilation chamber R1 to the atmosphere can be suppressed.

[0074] The ventilation structure 10a may also be configured as follows.

[0075] Figure 7 It is a diagram showing a first modification of the ventilation structure 10a. Figure 8 2 is a diagram showing a second modification of the ventilation structure 10a. Figure 7 In the example shown, the ventilation structure 10a further includes a baffle 10ad. The baffle 10ad is provided relative to the outlet of the discharge hole 10aa. The baffle 10ad is composed of, for example, a rectangular plate member and is provided on the inner wall portion W23. The baffle 10ad is provided at the other end of the inner wall portion W23 in the left-right direction of the figure (the right side of the figure), and after extending from the other end toward the opening direction of the outlet of the discharge hole 10aa (the left-right direction of the figure), it bends and extends toward the discharge hole 10aa side (the upper side of the figure). The portion of the baffle 10ad that bends and extends toward the discharge hole 10aa side covers the entire discharge hole 10aa when viewed from the opening direction of the outlet of the discharge hole 10aa. The baffle 10ad can be provided in a manner that covers at least a portion of the discharge hole 10aa.

[0076] exist Figure 8 In the example shown, the discharge hole 10aa is arranged to open to the storage chamber S at a position opposite to the tooth surface of the fourth gear G4. The baffle 10ad is arranged relative to the outlet of the discharge hole 10aa arranged in this way. Therefore, in this example, the baffle 10ad extends from the lower surface of the inner wall portion W23 of the portion on the left side of the figure (the front side in the rotation direction of the fourth gear G4 in the upper half) of the discharge hole 10aa toward the opening direction of the outlet of the discharge hole 10aa (the up and down direction of the figure), and then extends in a curved manner toward the discharge hole 10aa side (the right side of the figure). The baffle 10ad of the portion that curves and extends toward the discharge hole 10aa side covers the entire discharge hole 10aa when viewed from the opening direction of the outlet of the discharge hole 10aa. In the case of this example, it is preferred that the baffle 10ad is arranged in a manner that covers the entire discharge hole 10aa.

[0077] (4) In either case, the oil in the storage chamber S is blocked by the baffle 10ad provided relative to the outlet of the discharge hole 10aa, preventing it from reaching the discharge hole 10aa. Therefore, in these examples, the baffle 10ad can prevent the oil in the storage chamber S from entering the front chamber R2 through the discharge hole 10aa. As a result, in the case of the first variant, the discharge of oil to the atmosphere that is promoted by the oil entering from the discharge hole 10aa can be further suppressed. In addition, in the case of the second variant, even in the case of a discharge hole 10aa that opens to the storage chamber S at a position opposite to the tooth surface of the fourth gear G4, the discharge of oil to the atmosphere that is promoted by the oil entering from the discharge hole 10aa can be suppressed.

[0078] Although the embodiments of the present invention have been described above, the above embodiments merely show a part of application examples of the present invention and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0079] Explanation of symbols

[0080] 10: Cabinet

[0081] 11: Box body (first box component)

[0082] 12: Shell (second box component)

[0083] 10a: Ventilation structure

[0084] 10aa: discharge hole

[0085] 10ab: Communication hole (first communication portion)

[0086] 10ac: ventilation pipe (second communication part)

[0087] 10ad: Bezel

[0088] 30: Differential gear (gear mechanism)

[0089] 100: Power transmission device

[0090] G4: Fourth gear (gear)

[0091] R1: Ventilation chamber

[0092] R2: Front Room

[0093] S: Storage room

[0094] W11, W12, W13, W14, W15, W16: Inner wall portion (first inner wall portion)

[0095] W21, W22, W23, W24: Inner wall portion (second inner wall portion)

Claims

1. A ventilation structure provided in a box having a first box member and a second box member which are connected to each other to form a storage chamber, wherein: The ventilation structure has: A ventilation chamber formed by butting a first inner wall portion as the inner wall portion of the first box body member and a second inner wall portion as the inner wall portion of the second box body member to form an enclosed empty chamber, and provided with a first communication portion communicating with the storage chamber and a second communication portion communicating with the atmosphere; The front chamber is located between the storage chamber and the ventilation chamber and is adjacent to the ventilation chamber. The front chamber is a hollow chamber surrounded by the first inner wall portion and the second inner wall portion being butted against each other.

2. The ventilation structure according to claim 1, wherein: The front chamber is provided with a discharge hole for discharging the oil that has infiltrated the front chamber to the storage chamber.

3. The ventilation structure according to claim 2, wherein: The storage chamber stores a gear mechanism. The discharge hole opens toward the storage chamber at a position that does not face a tooth surface of a gear of the gear mechanism.

4. The ventilation structure according to claim 2 or 3, wherein: Furthermore, a baffle plate for shielding the oil in the storage chamber is provided relative to the outlet of the discharge hole.

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