Power transmission device

Abstract

The utility model relates to a power transmission device, which can make a ventilation device into a simple structure, inhibit the leakage of lubricating oil from the ventilation device and adjust the pressure in a shell. In a power transmission device (16) in which a countershaft (52) is housed in a housing (70) and in which a breather (90) for connecting the inside and the outside of the housing (70) is provided, (a) the countershaft (52) has a tubular shape extending in the direction of a second axis (C2) and is disposed above the oil level position (P1) of lubricating oil (OIL), and (b) the countershaft (52) is disposed in the direction of the second axis (C2) and is disposed below the oil level position (P1) of the lubricating oil (OIL). (b) A suction / exhaust path (92) provided between the countershaft (52) and the breather (90) has an axis extension section (92a) connected to the hollow section (52i) of the countershaft (52) and extending in the direction of the second axis (C2), and an upward extension section (92b) connected by bending toward the side of the axis extension section (92a) opposite the hollow section (52i) and extending upward.

Description

Technical Field

[0001] This utility model relates to a power transmission device, wherein the power transmission shaft of the power transmission device is housed in a housing, and the power transmission device is provided with a ventilation device that connects the inside of the housing with the outside. Background Technology

[0002] A known power transmission device houses a gearbox within a housing and includes a venting device that connects the interior of the housing to the exterior. For example, this is described in Patent Document 1. In the power transmission device described in Patent Document 1, air containing lubricating oil flowing from the interior of the housing into the venting device is separated into lubricating oil and air by a separation wall located in the separation chamber of the venting device. The separated lubricating oil returns to the interior of the housing via a return oil passage, while the air is discharged to the exterior of the housing.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-119666 Utility Model Content

[0006] The problem to be solved by the utility model

[0007] In the power transmission device described in Patent Document 1, the venting device has a complex structure with a separation chamber, a return oil passage, etc. Therefore, there is a need for a power transmission device that has a simple structure, can prevent lubricating oil from leaking out of the venting device, and can adjust the pressure inside the housing.

[0008] This invention was made against the background described above, and its purpose is to provide a power transmission device that makes the ventilation device into a simple structure, and is able to suppress the leakage of lubricating oil from the ventilation device and adjust the pressure inside the housing.

[0009] Methods for solving problems

[0010] The present invention relates to a power transmission device, wherein the power transmission shaft of the power transmission device is housed within a housing, and the power transmission device is provided with a venting device that connects the interior and exterior of the housing, wherein (a) the power transmission shaft is cylindrical extending in the axial direction and is positioned above the actual operating oil level of the lubricating oil, and (b) the intake and exhaust path provided between the power transmission shaft and the venting device has an axial extension and an upper extension, the axial extension being connected to the hollow portion of the power transmission shaft and extending in the axial direction, the upper extension being bent and connected to the side of the axial extension opposite to the hollow portion and extending upward.

[0011] Effects of the utility model

[0012] According to this invention, (a) the power transmission shaft is a cylindrical shape extending in the axial direction and is positioned above the actual operating oil level of the lubricating oil; (b) the intake and exhaust path provided between the power transmission shaft and the venting device has an axial extension and an upper extension. The axial extension is connected to the hollow portion of the power transmission shaft and extends in the axial direction. The upper extension bends and connects to the side of the axial extension opposite to the hollow portion and extends upward. Air and lubricating oil are separated in the hollow portion of the power transmission shaft by gas-liquid separation caused by centrifugal force generated by the rotation of the power transmission shaft. Air and lubricating oil are separated in the intake and exhaust paths by gas-liquid separation caused by inertial impact. Thus, the venting device is made with a simple structure, and by utilizing the centrifugal force generated by the rotation of the power transmission shaft and the gas-liquid separation caused by inertial impact in the intake and exhaust paths, leakage of lubricating oil from the venting device can be suppressed, and the pressure inside the housing can be adjusted. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating the general structure of a vehicle equipped with a power transmission device employing this invention.

[0014] Figure 2 This diagram illustrates the configuration of the main shaft, secondary shaft, and a pair of drive shafts when viewed along the second axis.

[0015] Figure 3 This diagram illustrates the gas-liquid separation effect caused by the rotation of the secondary shaft, and the gas-liquid separation effect caused by inertial collisions in the intake and exhaust paths between the ventilation device and the secondary shaft.

[0016] Explanation of reference numerals in the attached figures

[0017] 16: Power transmission device; 52: Secondary shaft (power transmission shaft); 52i: Hollow section; 70: Housing; 90: Ventilation device; 92: Intake and exhaust path; 92a: Shaft extension; 92b: Upper extension; C2: Second shaft (axis); OIL: Lubricating oil; P1: Oil level (actual operating oil level). Detailed Implementation

[0018] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the drawings have been appropriately simplified or modified in the embodiments, and the dimensions, proportions, and shapes of the various parts may not be drawn correctly.

[0019] Example

[0020] Figure 1 This is a schematic diagram illustrating the general structure of a vehicle 10 equipped with the power transmission device 16 of this invention. The vehicle 10 is equipped with the power transmission device 16 in the power transmission path between the engine 12 and a pair of drive wheels 14. The engine 12 is a known internal combustion engine, serving as the power source for driving. The vehicle 10 is, for example, a FR (front-engine, rear-wheel drive) vehicle. The power transmission device 16, starting from the engine 12 side, sequentially includes a clutch K1, a bevel gear pair 24, a transmission 26, and a differential gear 58. The bevel gear pair 24, the transmission 26, and the differential gear 58 within the power transmission device 16 are housed within a housing 70, which is a non-rotating component. One side of the clutch K1 is connected to the engine 12 via a drive shaft 18, and the other side is connected to one of the bevel gear pairs 24. The other side of the bevel gear pair 24 is connected to the main shaft 28 of the transmission 26, which will be described later.

[0021] The transmission 26 is equipped with a main shaft 28 and a countershaft 52 arranged parallel to each other and horizontally. It is a parallel dual-shaft transmission that establishes multiple gear stages (transmission stages) by decelerating or accelerating the rotation of the main shaft 28 at a predetermined gear ratio γ (also called the gear ratio) γ (= rotational speed of the main shaft 28 / rotational speed of the countershaft 52). The main shaft 28 is configured to rotate about a first axis C1, and the countershaft 52 is configured to rotate about a second axis C2. The direction of the first axis C1 and the direction of the second axis C2 are the same horizontally extending direction. The second axis C2 corresponds to the "axis" in this invention. The countershaft 52 includes a main rotating shaft portion 54 and a gear rotating shaft portion 56, which are connected to each other by a spline engagement portion 52s to prevent relative rotation. The countershaft 52 is connected to the differential gear 58 by the engagement of the output gear 56g provided on the gear rotating shaft portion 56 with the final drive gear 58a provided on the differential gear 58. The differential gear 58 is connected to a pair of drive wheels 14 via a pair of drive shafts 20. The pair of drive shafts 20 are rotatably configured around a third axis C3, which is parallel to the second axis C2.

[0022] The transmission 26 is equipped with multiple gear pairs 30. Each gear pair 30 has: a driving gear 32, which is fixedly mounted on the main shaft 28 without relative rotation; and a driven gear 34, which is always meshed with the driving gear 32 and is mounted on the main rotating shaft 54 ​​with relative rotation capability but immovable in the direction of the second axis C2. As multiple gear pairs 30, a reverse gear pair 30a, a 2-speed gear pair 30b, a 1-speed gear pair 30c, a 4-speed gear pair 30d, a 5-speed gear pair 30e, a 6-speed gear pair 30f, and a 3-speed gear pair 30g are arranged sequentially from one direction to the other in the direction of the first axis C1 (=the direction of the second axis C2). As the gear ratio γ gradually decreases from the 1-speed gear pair 30c to the 2-speed gear pair 30b, the 3-speed gear pair 30g, the 4-speed gear pair 30d, the 5-speed gear pair 30e, and the 6-speed gear pair 30f. To reverse the direction of rotation, the reverse gear pair 30a has an intermediate gear 36 between the driving gear 32 and the driven gear 34, which meshes with both. Hereinafter, unless otherwise specified, the reverse gear pair 30a to the 3rd speed gear pair 30g will be referred to as "gear pair 30". When the driving gear 32 of the gear pair 30 rotates, the driven gear 34 rotates at a rotational speed corresponding to the gear ratio γ of the gear pair 30.

[0023] In the direction of the second axis C2, the transmission 26 is equipped with switching mechanisms 40 on one side of the driven gear 34 of the reverse gear pair 30a, between each driven gear 34 of the 2nd speed gear pair 30b and the 1st speed gear pair 30c, between each driven gear 34 of the 4th speed gear pair 30d and the 5th speed gear pair 30e, and between each driven gear 34 of the 6th speed gear pair 30f and the 3rd speed gear pair 30g. Each switching mechanism 40 is fixed to the main rotating shaft portion 54 of the secondary shaft 52 and is movably mounted in the direction of the second axis C2. Each switching mechanism 40 has a switching engagement tooth 42 at a position opposite to the driven gear 34 in the direction of the second axis C2. Each driven gear 34 has a gear-side engagement tooth 44 at a position opposite to the switching mechanism 40 in the direction of the second axis C2, capable of engaging with the switching engagement tooth 42. A switching mechanism 40 equipped with a switching engagement tooth 42 and a driven gear 34 equipped with a gear-side engagement tooth 44 constitute a dog-tooth clutch 50 as an engagement clutch.

[0024] The shift mechanism 60 is equipped with a shift fork 62, a shift sleeve 64, and a shift actuator 66, which are respectively fitted into the shift mechanism 40. The shift sleeve 64 has shift grooves 68 formed, which, via the shift fork 62, define the movement position of the shift mechanism 40 in the direction of the second axis C2. The transmission 26 moves the shift mechanism 40 to a predetermined position in the direction of the second axis C2 according to the rotational position of the shift sleeve 64, thereby switching the on / off state of the dog clutch 50 and performing gear changes. For example, when the driven gear 34 of the reverse gear stage Rev is connected to the countershaft 52 via the shift mechanism 40, a reverse gear stage Rev is formed in the transmission 26. The same applies to the 1st to 6th gear stages.

[0025] Figure 2 This diagram illustrates the configuration of the main shaft 28, the secondary shaft 52, and a pair of drive shafts 20 as viewed along the second axis C2. The housing 70 is constructed by assembling multiple housing components together using fasteners such as bolts. Figure 2 In the diagram, for housing 70, only the outer edge of the housing that is fastened with fasteners is shown.

[0026] For example, lubricating oil, such as ATF (Automatic Transmission Fluid), is stored at the bottom of the housing 70. The oil level position P1 is the height of the lubricating oil stored at the bottom of the housing 70 under normal conditions. "Normal conditions" differs from the temporary states of the vehicle 10 such as rapid acceleration / deceleration, driving on inclines, or sharp turns, which will be described later; it refers to a relatively long and continuous driving state. The oil level position P1 corresponds to the "actual operating oil level" in this invention. The drive gear 32, fixedly mounted on the main shaft 28, is located at the position that allows the lubricating oil to be stirred up, which is the oil level position P1. On the other hand, the countershaft 52 and the driven gear 34 mounted on the countershaft 52 are not located at the position that allows the lubricating oil to be stirred up, which is the oil level position P1. The lubricating oil is stirred up by the drive gear 32, and is used to lubricate the gears and bearings within the housing 70. In addition, as the gear (e.g., driven gear 34) inside the housing 70 rotates, the lubricating oil adhering to the gear is further splashed around.

[0027] Figure 3 This diagram illustrates the gas-liquid separation effect generated by the rotation of the secondary shaft 52 and the gas-liquid separation effect generated by the inertial collision in the intake and exhaust path 92 provided between the ventilation device 90 and the secondary shaft 52. Figure 3 yes Figure 2 The cross-sectional view shown by cut line iii-iii.

[0028] The main rotating shaft portion 54 and the gear rotating shaft portion 56 are both cylindrical (e.g., cylindrical) extending in the direction of the second axis C2, and are positioned above the oil level P1 of the lubricating oil. The main rotating shaft portion 54 has a hollow portion 54i near the second axis C2. Multiple through holes 54h are provided in the main rotating shaft portion 54, extending from the hollow portion 54i to the outer periphery. The gear rotating shaft portion 56 has a hollow portion 56i near the second axis C2. The hollow portion 52i of the secondary shaft 52 includes both hollow portions 54i and 56i, which are connected in the direction of the second axis C2. The secondary shaft 52 and the hollow portion 52i correspond to the "power transmission shaft" and "hollow portion" in this invention, respectively.

[0029] The countershaft 52 is supported in the housing 70 by a plurality of bearings 80. For example, when the transmission 26 is assembled in such a way that it is housed within the housing 70, an opening 70o is provided in the housing 70 along the extension of the countershaft 52 in the direction of the second axis C2 of the countershaft 52. The cover 72 is fastened to block the opening 70o by fasteners. For example, a cylindrical path is integrally formed in the cover 72 by casting. This cylindrical path is an intake / exhaust path 92 provided between the venting device 90 and the countershaft 52. The venting device 90 is a known venting device that communicates the interior and exterior of the housing 70. The intake / exhaust path 92 becomes an exhaust path when the pressure inside the housing 70 is higher than the pressure outside the housing 70, and an intake path when the pressure inside the housing 70 is lower than the pressure outside the housing 70. When the cover 72 is fastened to the housing 70, one end of the intake / exhaust path 92 is formed at a position where it is inserted into the hollow portion 52i of the countershaft 52. Thus, the intake and exhaust path 92 can be formed without adding a manufacturing process when casting the cover 72. Furthermore, the intake and exhaust path 92 is formed such that, during the assembly of the cover 72, one end of the secondary shaft 52 overlaps with the intake and exhaust path 92 in the direction of the second axis C2. A venting device 90 is installed at the other end of the intake and exhaust path 92. Thus, the intake and exhaust path 92 is provided between the secondary shaft 52 and the venting device 90. The intake and exhaust path 92 has an axis extension 92a and an upper extension 92b. The axis extension 92a is the portion connected to the hollow portion 52i of the secondary shaft 52 and extending in the direction of the second axis C2. The upper extension 92b is the portion of the axis extension 92a that is bent and connected to the side opposite to the hollow portion 52i and extends upwards. The bent portion 92c is the connecting portion between the axis extension 92a and the upper extension 92b. In this embodiment, the axis extension 92a extends from the hollow portion 52i of the secondary shaft 52 toward the bend 92c in the direction of the second axis C2. The upper extension 92b extends from the bend 92c toward the ventilation device 90 in the direction of the vertical line. Thus, the intake and exhaust path 92 bends 90 degrees at the bend 92c.

[0030] There are instances where lubricating oil flows into the hollow section 52i even though it is not actively supplied. For example, during vehicle operation, when the rotational speed of the drive gear 32 becomes high-speed, the lubricating oil is violently agitated and foamed, and the pressure inside the housing 70 increases. Consequently, the oil level of the lubricating oil becomes higher than the oil level P1. When foamed air containing lubricating oil flows into the hollow section 52i, the air is separated from the lubricating oil in the hollow section 52i by means of the gas-liquid separation caused by the centrifugal force generated by the rotation of the secondary shaft 52. Specifically, the relatively dense lubricating oil moves towards the outer periphery of the secondary shaft 52 due to centrifugal force, while the relatively less dense air remains near the second axis C2 of the secondary shaft 52, thereby separating the air from the lubricating oil. The separated lubricating oil is discharged from the hollow portion 52i of the secondary shaft 52 through the through hole 54h to the outside of the secondary shaft 52. Alternatively, the separated lubricating oil flows in the direction of arrow F1 and is discharged from the hollow portion 52i of the secondary shaft 52.

[0031] When the pressure inside the housing 70 increases compared to the pressure outside the housing 70, and air containing lubricating oil flows from the hollow portion 52i into the intake / exhaust path 92 in the direction of arrow F2a, the air containing lubricating oil collides with the bend portion 92c due to inertia. Hereinafter, the collision caused by inertia will be referred to as "inertial collision". The air and lubricating oil are separated by the gas-liquid separation effect generated by this inertial collision. Specifically, the relatively dense lubricating oil remains in the bend portion 92c due to the inertial collision, while the relatively less dense air does not remain in the bend portion 92c and flows upward towards the extension portion 92b in the direction of arrow F2b. The separated lubricating oil passes through the axis extension portion 92a and returns to the hollow portion 52i of the sub-shaft 52. The oil level position P2 is the height position at which the oil level can temporarily reach its highest position during rapid acceleration / deceleration of the vehicle 10, driving on an inclined road, or sharp turns. The length of the upper extension 92b is set such that the vent 90 is positioned above the oil level P2. Therefore, even if the lubricating oil level temporarily rises, leakage of lubricating oil from the vent 90 is suppressed.

[0032] According to this embodiment, (a) the secondary shaft 52 is a cylindrical shape extending in the direction of the second axis C2, and is positioned above the oil level P1 of the lubricating oil. (b) the intake / exhaust path 92 provided between the secondary shaft 52 and the venting device 90 has an axis extension 92a and an upper extension 92b. The axis extension 92a is connected to the hollow portion 52i of the secondary shaft 52 and extends in the direction of the second axis C2. The upper extension 92b bends and connects to the side of the axis extension 92a opposite to the hollow portion 52i, and extends upward. Air and lubricating oil are separated in the hollow portion 52i of the secondary shaft 52 by means of the gas-liquid separation effect caused by the centrifugal force generated by the rotation of the secondary shaft 52. Furthermore, air and lubricating oil are separated in the intake / exhaust path 92 by means of the gas-liquid separation effect caused by inertial impact. In this way, the ventilation device 90 can be made into a simple structure, and the leakage of lubricating oil from the ventilation device 90 can be suppressed by the centrifugal force generated by the rotation of the secondary shaft 52 and the gas-liquid separation effect caused by the inertial collision in the intake and exhaust paths 92, and the pressure inside the housing 70 can be adjusted.

[0033] Furthermore, the above description is an embodiment of the present invention. Without departing from its spirit, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[0034] In the previously described embodiment, the intake and exhaust path 92 bends at the bend 92c by 90 degrees, but is not limited to this. As long as the gas-liquid separation effect generated by the inertial collision is functional, the bend angle can exceed 90 degrees or be less than 90 degrees. In the previously described embodiment, the upper extension 92b extends upward from the bend 92c in the direction of the vertical line, but is not limited to this. The upper extension 92b can extend upward as long as it does not extend from the bend 92c in the direction of the vertical line. In the previously described embodiment, vehicle 10 is a FR (front-engine, front-wheel drive) vehicle; however, this invention can also be applied to FF (front-engine, front-wheel drive), MR (mid-engine, rear-wheel drive), and four-wheel drive vehicles.

Claims

1. A power transmission device, wherein the power transmission shaft of the power transmission device is housed within a housing, and the power transmission device is provided with a venting device that connects the interior of the housing to the exterior, characterized in that, The power transmission shaft is a cylindrical shape extending in the axial direction, and is positioned above the actual operating oil level of the lubricating oil. The intake and exhaust path disposed between the power transmission shaft and the ventilation device has an axial extension and an upper extension. The axial extension is connected to the hollow portion of the power transmission shaft and extends in the axial direction. The upper extension bends and connects to the side of the axial extension opposite to the hollow portion.

Images