KR101265013B1 - Automatic Transmission - Google Patents

Abstract

An object of the present invention is to achieve the axial support strength performance, the breather performance and the inclined air intake prevention performance, which are the unit demand performance of the automatic transmission.
The automatic transmission includes a transmission case 1, a transmission input / output shaft 4 and 5 having a first shaft center C1, an idler shaft 6 having a second shaft center C2, and a third shaft center C3. The drive shafts 7 and 7 which have, the oil pan 30, the inner wall rib 32, and the return flow path 33 are provided. The inner wall rib 32 is formed in the differential gear inner wall 46 along the differential final gear 24 of the transmission case 1, and drives in the wall region between the first shaft center C1 and the third shaft center C3. The case strength around the shaft of the shafts 7 and 7 is increased. In the return flow path 33, the oil inlet 51 is opened above the inner wall rib 32 to return the hydraulic oil ATF from the oil inlet 51 to the oil pan 30.

Description

[0001] AUTOMATIC TRANSMISSION [0002]

The present invention relates to an automatic transmission having an oil pan and a transmission case in which operating oil is used for shift operation, lubrication, cooling, and the like.

Background Art [0002] Conventionally, as an automatic transmission having a transmission case and an oil pan in which hydraulic oil is stored, a baffle plate is provided around the differential final gear so as to separate the hydraulic fluid around the differential final gear to the differential final gear side and the transmission case side. It is known (for example, refer patent document 1).

Japanese Patent No. 4074278

However, in the conventional automatic transmission, a baffle plate is provided around the differential final gear. For this reason, even if it intends to raise the support strength of a final shaft, even if it tries to form an inner wall rib in the differential gear inner wall according to differential final gear among transmission cases, it interfered with the baffle plate and there existed a problem that an inner wall rib could not be formed. .

Therefore, when the inner wall ribs are formed without the baffle plate, the stirring flow rate reduced by the baffle plate not only increases, but the inner wall ribs inhibit the inflow of the working oil into the oil dropping hole through the oil pan. For this reason, when the oil is scraped up by the differential final gear in a state in which the oil level is inclined greatly in the case of rapid start or turning, for example, the flow rate of the hydraulic oil that accumulates in the breather space above the oil level increases. That is, by increasing the flow rate that is accumulated in the breather space and not returning to the oil pan, the effective flow rate of the working oil stored due to the suction of the oil pump decreases, thereby lowering the level of the oil level. As described above, when the oil level inclination is applied while the oil level is lowered, there is a problem that the oil pump may suck air from the oil strainer.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide an automatic transmission that can achieve both axial support strength performance, breather performance, and inclined air suction prevention performance, which are unit required performances of an automatic transmission.

In order to achieve the above object, the automatic transmission of the present invention is a transmission case, a transmission shaft having a first shaft core, an idler shaft having a second shaft core, a final shaft having a third shaft core, an oil pan, and inner wall ribs. And means for providing a return flow path.

The transmission case is a breather space in which operating oil is stored and communicates with the outside air above the oil level.

The transmission shaft having the first shaft center is supported by the transmission case and has a transmission mechanism for shifting the input rotation speed.

The idler shaft having the second shaft center is case-supported at a position above the first shaft center and has an idler gear meshed with the output gear provided on the transmission shaft.

The final shaft having the third shaft core is case-supported at a position lower than the first shaft core and the second shaft core, and has a differential final gear meshed with an idler final gear provided on the idler shaft.

The oil pan is installed in the transmission case to store the hydraulic oil and has an oil strainer set at an inlet of an oil pump.

The inner wall ribs are formed on the inner wall of the differential gear in accordance with the differential final gear in the transmission case to increase the strength around the axis of the final shaft in the wall region between the first and third shaft cores.

The return flow path opens an oil inlet at a position above the inner wall rib, and returns the hydraulic oil from the oil inlet to the oil pan.

Therefore, the inner wall rib formed on the inner wall of the differential gear in accordance with the differential final gear increases the case strength around the shaft of the final shaft, thereby improving the support strength of the final shaft.

During traveling, the hydraulic fluid moved or scattered to the breather space flows in from the oil inlet opening open to the upper position of the inner wall rib and returns to the oil pan after the return flow path.

That is, the flow of the action of increasing the return flow rate from the return flow passage → decrease the flow rate accumulated in the breather space → decrease the scattering flow rate caused by the gears due to rapid oil inflow from the oil inlet located above the inner wall rib. do.

Therefore, the reduction of the effective flow rate of the hydraulic fluid stored in the transmission case and the oil pan is suppressed, and the oil level of the hydraulic oil is managed so as to maintain the oil level at a predetermined level. In this oil level managed state, even if the oil level inclination is applied by, for example, sudden start or turn, the oil pump is prevented from sucking air from the oil strainer.

As a result, the axial support strength performance, the breather performance, and the inclined air suction prevention performance, which are the unit demand performance of the automatic transmission, can be achieved together.

BRIEF DESCRIPTION OF THE DRAWINGS The expanded sectional drawing which shows the whole structure of the automatic transmission of 1st Example.
Fig. 2 is a diagram showing a transmission case seen from the converter cover side of the automatic transmission of the first embodiment.
Fig. 3 is a diagram showing a transmission case viewed from the transmission mechanism end cover side of the automatic transmission of the first embodiment.
Fig. 4 is a diagram showing a transmission case seen from the oil pan side of the automatic transmission of the first embodiment.
5 is a cross-sectional perspective view taken along the line AA of FIG. 2 showing a return flow path of the automatic transmission of the first embodiment.
FIG. 6 is an operation explanatory diagram showing the hydraulic oil return action from the return flow path in the automatic transmission of the first embodiment; FIG.

EMBODIMENT OF THE INVENTION Hereinafter, the best form which implements the automatic transmission of this invention is demonstrated based on the 1st Example shown in drawing.

[First Embodiment]

First, the configuration will be described.

1 is a developed cross-sectional view showing the overall configuration of an automatic transmission of the first embodiment. Hereinafter, the whole structure will be described based on FIG. 1.

As shown in FIG. 1, the automatic transmission AT of the first embodiment has a transmission having a transmission case 1, a converter cover 2, a transmission mechanism end cover 3, and a first shaft center C1. A transmission output shaft 5 (shift shaft) having an input shaft 4 (shift shaft), a first shaft core C1, an idler shaft 6 having a second shaft core C2, and a third shaft core C3. Drive shafts 7 and 7 (final shafts) are provided.

The automatic transmission AT is an automatic transmission of a stepped forward 4 speed retreat 1 speed applied to an FF car of front wheel drive, and shifts input rotation from an engine (not shown) according to a selected speed shift stage, thereby shifting front and rear left and right wheels. To transmit the engine driving force after shifting.

The transmission case 1 is called a transmission case and is a main case member which supports the transmission input / output shafts 4 and 5, the idler shaft 6 and the drive shafts 7 and 7 arranged in parallel. The converter cover 2 which covers the torque converter 8 is bolted to the flange surface of the one end side of this transmission case 1. And the transmission mechanism end cover 3 which covers the edge part of a transmission mechanism is bolted to the flange surface of the other end side of the transmission case 1. That is, the transmission case 1, the converter cover 2, and the transmission mechanism end cover 3 constitute a unit case of the automatic transmission AT.

The transmission input shaft 4 and the transmission output shaft 5 are arranged on the same first shaft center C1 and have a stepped transmission mechanism for shifting the input rotational speed by hydraulic control. An oil pump 9 which is rotationally driven by the engine and a flow path plate 10 having a pump suction path, a pump discharge path, and a clutch flow path are formed at an outer periphery of the transmission input shaft 4 and immediately behind the torque converter 8. It is bolted to the case 1. The stage shifting mechanism is a set of two planetary gears, each having a first planetary gear 11 and a second planetary gear 12, and as five shifting friction elements, the first clutch 13, the second clutch 14, and the first clutch. It has a three clutch 15, a first brake 16 and a second brake 17. Then, each shift stage of the forward 4th speed retreat 1st speed is achieved by fastening two shift friction elements, and the forward 4th speed is achieved by releasing one shift friction element and switching shift by fastening one frictional fastening element. do.

The idler shaft 6 is case-supported at a position above the first shaft center C1 and has an idler gear 19 meshed with the output gear 18 provided on the transmission output shaft 5. This idler gear 19 has the parking gear 20 by an integral structure. One end of the idler shaft 6 is supported by the first idler bearing 21 with respect to the transmission case 1, and the other end thereof is supported by the second idler bearing 22 with respect to the converter cover 2.

The drive shafts 7 and 7 are case-supported in lower positions than the first shaft core C1 and the second shaft core C2 and are engaged with the idler final gear 23 provided on the idler shaft 6 to achieve the longitudinal reduction ratio. Has a differential final gear 24. Here, between the differential final gear 24 and the drive shafts 7 and 7, the differential case 25 for fixing the differential final gear 24 and the side gear for spline-fitting the drive shafts 7 and 7 ( The differential units having 26 and 26 are interposed. One end of the differential case 25 is supported by the first differential bearing 27 with respect to the transmission case 1, and the other end thereof is supported by the second differential bearing 28 with respect to the converter cover 2.

2 to 4 are diagrams showing a transmission case of the automatic transmission AT of the first embodiment, and FIG. 5 is a sectional perspective view showing a return flow path of the automatic transmission AT of the first embodiment. Hereinafter, the main part configuration will be described based on FIGS. 2 to 5.

As shown in FIGS. 2 to 5, the automatic transmission AT of the first embodiment includes a transmission case 1, a first shaft center C1, a second shaft center C2, and a third shaft center C3. And an oil pan 30, a communicating oil hole 31, an inner wall rib 32, a return flow path 33, an approach guide surface 34, and a rectifying part 35.

As shown in FIG. 2, the transmission case 1 is a breather space in which hydraulic oil ATF is stored in the case chamber 36 and the space above the stop oil surface W communicates with the outside air in the stopped state. .

Here, the stationary oil level W refers to the oil level when the vehicle equipped with the automatic transmission AT is stopped on the flat road surface, and the sensitivity of the oil surface fluctuations is blunted and the volume of the breather space is secured widely. In order to do this, the position is set slightly higher than the height of the first shaft center C1. In the vehicle stop state or the like, the hydraulic oil ATF is stored in the case chamber 36 and the oil pan chamber 37 below the stop oil surface W. As shown in FIG.

As shown in FIGS. 2 and 3, the oil pan 30 is provided by closing the opening of the lower surface of the control valve unit 38 set in the lower position of the transmission case 1 in an oil-tight state. And the oil pan chamber 37 which stores hydraulic fluid ATF is formed by blocking the opening of the control valve unit 38 by the oil pan 30. The oil pan chamber 37 has an oil strainer 40 set at the suction port 39 (see FIG. 4) of the oil pump 9. Moreover, the discharge port 41 from the oil pump 9 is open to the control valve unit 38 as shown in FIG. As shown in FIG. 2, the suction port 39 and the discharge port 41 of the oil pump 9 communicate with the pump suction path 42 and the pump discharge path 43 formed in the flow path plate 10.

As shown in FIG. 2, the communication oil hole 31 is opened in a lower position than the stop oil surface W of the hydraulic oil ATF stored in the case chamber 36 of the transmission case 1. (36) and the oil pan chamber 37 communicate with each other. As shown in FIG. 2, the communication oil hole 31 is a lower position of an intermediate portion of the first shaft core C1 and the second shaft core C2, and is formed from the case flange portion 44 and the case flange portion 44. It is enclosed in V shape by the rectification extension part 45 of, and it is set to the position which suppresses the fluctuation | variation of the oil surface.

2 and 5, the inner wall rib 32 is formed by being raised to the differential gear inner wall 46 along the differential final gear 24 in the transmission case 1, and the first shaft center C1. And the case strength around the axis of the drive shafts 7 and 7 in the wall region between the and the third shaft center C3. This inner wall rib 32 has a 1st inner wall rib 32a, the 2nd inner wall rib 32b, and the 3rd inner wall rib 32c. The first inner wall rib 32a connects the bearing boss 47 of the drive shafts 7 and 7 and the mounting case portion 48 of the flow path plate 10 provided around the shaft of the first shaft center C1 in the radial direction. do. The second inner wall rib 32b connects the bearing boss 47 of the drive shafts 7 and 7 and the case flange portion 44 of the transmission case 1 in the radial direction. The third inner wall rib 32c protrudes from the bearing boss 47 of the drive shafts 7 and 7 in a radial direction to extend the position between the first inner wall rib 32a and the second inner wall rib 32b. . Further, each connecting portion forms a smooth connecting circular arc surface to avoid stress concentration. Moreover, in order to raise the case strength of the area | regions other than the inner wall rib 32 among the axis of the drive shafts 7 and 7, as shown in FIG. 3, the outer wall rib 50 is raised to the differential gear outer wall 49. As shown in FIG. To form. As outer wall rib 50, the 1st outer wall rib 50a arrange | positioned in the horizontal direction, the 2nd outer wall rib 50b, the 3rd outer wall rib 50c, the 4th outer wall rib 50d, and the 5th It has outer wall rib 50e.

As shown in Figs. 2 and 5, the return flow path 33 opens the oil inlet 51 at an upper position of the inner wall rib 32, and supplies hydraulic oil (ATF) moved or scattered to the breather space. Return from oil inlet 51 to oil pan 30. As shown in FIG. 5, the return flow path 33 is an inclined surface perpendicular to the visual direction when viewed from the inclined upper side toward the differential gear inner wall 46 (for example, an inclined surface having an inclination angle of about 45 degrees). The oil inlet 51 is opened. The detailed opening position of the oil inflow port 51 is the position below the 2nd shaft center C2, and is set as the upper position of the inner wall rib 32. As shown in FIG. Moreover, between the transmission mechanism case part 1a and the differential case part 1b of the transmission case 1, the return passage cross-sectional area of the return flow path 33 is ensured as shown in FIG.

The approach guide surface 34 is formed in the differential gear inner wall 46 between the second shaft center C2 and the third shaft center C3, as shown in FIGS. 2 and 5, and is separated from the breather space. ), The hydraulic oil (ATF) is collected and guided to the oil inlet (51). That is, the approach guide surface 34 has a stepped surface shape with a smooth curved slope so that the hydraulic oil (ATF) flows with low resistance without providing a rib.

As shown in FIG. 2, the rectifying unit 35 is formed in the transmission case 1 and has a first rectifying surface 35a and a second rectifying surface 35b. The first rectifying surface 35a has a shape that conforms to the outer shape of the differential final gear 24, so that the hydraulic oil ATF scraped and moved by the rotation of the differential final gear 24 faces the approach guide surface 34. Rectify. The second rectifying surface 35b has a shape that conforms to the outer shape of the idler gear 19, and rectifies the hydraulic oil ATF moving by the rotation of the idler gear 19 toward the approach guide surface 34.

Next, the operation will be described.

First, "the unit performance of an automatic transmission" will be described. Subsequently, the operation in the automatic transmission AT of the first embodiment will be explained by dividing into "achievement of the unit required performance", "inclined surface opening action of the oil inlet", and "oil surface management action of the working oil".

[Unit performance of automatic transmission]

As the unit performance of the automatic transmission, the shaft support strength performance to maintain the support strength of the shaft supported by the case, the breather performance to ensure the air communication of the breather chamber, and the inclined air intake prevention performance to prevent air intake from the oil pump Required.

First, axial support strength performance is described. The aspect ratio of the automatic transmission is achieved by engaging an idler final gear installed on the idler shaft and a differential final gear installed on the final shaft. For this reason, the drive torque transmitted to the final shaft is large and fluctuates in oscillation at the time when the forward 1 speed is selected. With respect to this transmission drive torque, in order to suppress case deformation and receive reaction force by the bearing, it is necessary to increase the support strength of the transmission case on which the bearing is supported.

Therefore, when increasing the drive strength of the drive shaft by the differential case part which surrounds a differential final gear in a transmission case, since it partially overlaps with a transmission mechanism case part, the outer wall rib cannot raise the support strength of the whole circumferential area of a final shaft. For this reason, improvement of the support strength in the area | region where an outer wall rib cannot be provided is inevitably set to the inner wall rib.

That is, the inner wall ribs are formed in the area of the differential case inner wall between the transmission shaft and the final shaft of the transmission mechanism in the differential case portion, whereby the supporting strength of the entire circumferential region of the final shaft can be increased. In this case, however, the inner wall ribs are formed, which is the same area as the inner wall ribs and is disposed at a position lower than the stop oil surface to prevent the inflow of the hydraulic oil into the communication hole communicating the case chamber and the oil pan chamber.

For this reason, for example, when the hydraulic oil is scraped up by the differential final gear in a state in which the oil level is greatly inclined, for example, in a sudden start and a high lateral acceleration G, or a turning run that generates a high lateral acceleration G. As a result, the flow rate of the hydraulic oil that accumulates near the entrance to the breather space above the stop surface increases. In other words, the breather performance is reduced.

And the flow volume which does not return to an oil pan room in the state which stuck to the breather space increases, and the effective flow volume of the hydraulic oil stored in the case room and the oil pan room decreases, and the oil level is reduced. In this way, when the oil level inclination is applied in the state where the oil level is lowered, the oil pump sucks air from the oil strainer, and the inclination air suction prevention performance is not secured.

On the other hand, if the inner wall ribs are not set, it is possible to secure the breather performance and the inclined air suction prevention performance, but the shaft support strength performance and the breather performance, which are the unit required performance of the automatic transmission, are as if the shaft support strength performance cannot be secured. At the expense of any of the over-inclined air intake prevention performance, or all of them compromise with low performance.

[Achievement of Unit Required Performance]

As described above, in the automatic transmission, it is an important problem to achieve both the axial support strength performance, the breather performance, and the inclined air suction prevention performance. Hereinafter, the effect of achieving the required unit performance in the automatic transmission AT of the first embodiment reflecting this will be described.

(Axial support strength performance)

First, the inner wall ribs 32 formed on the differential gear inner wall 46 along the differential final gear 24 and the outer wall ribs 50 formed on the differential gear outer wall 49 along the differential final gear 24 are driven. The case strength of the transmission case 1 around the shaft of the shafts 7 and 7 becomes high.

For this reason, the case strength around the 1st differential bearing 27 which supports the drive shafts 7 and 7 rotatably becomes high, and the support strength of the drive shafts 7 and 7 improves.

(Breather performance)

During traveling, the hydraulic oil ATF moved or scattered into the breather space flows in from the oil inlet 51 opened at a position higher than the stop oil surface W of the hydraulic oil ATF as shown in FIG. After 33, the oil pan chamber 37 is returned.

On the other hand, of the hydraulic fluid ATF which moved and scattered to the breather space during the run, the hydraulic oil ATF which did not flow from the oil inlet port 51 and dropped to the oil surface of the case chamber 36 is then connected to the communication hole ( 31), the oil pan chamber 37 is returned.

That is, when the hydraulic oil ATF flows in from the oil inlet 51 at the position higher than the stop oil surface W, the time response is compared with the case where the hydraulic oil flows into the communication hole 31 at the position lower than the stop oil surface W. This leads to a good rapid oil inflow. As the return flow rate from the return flow path 33 increases, the flow of the action of increasing the return flow rate from the return flow path 33 → decreasing the flow rate accumulated in the breather space → decreasing the scattering flow rate by the gear is repeated. .

In this way, the flow rate accumulated in the breather space is reduced, so that the accumulation of oil at the breather entrance and exit is eliminated, and the breather function is secured.

(Inclined air suction prevention performance)

As described above, the flow of the action of increasing the return flow rate from the return flow passage 33 → decrease the flow rate accumulated in the breather space → decrease the scattering flow rate by the gear is repeated, whereby the case chamber 36 and the oil pan chamber ( The decrease in the effective flow rate of the hydraulic oil (ATF) stored in 37) is suppressed. In other words, the oil level of the hydraulic oil ATF is managed so as to maintain the level of the stop oil surface W at a predetermined level. In this state of oil level management, even if oil level inclination is applied, for example, by sudden start or turn, the operating oil communication between the case chamber 36 and the oil pan chamber 37 through the communication oil hole 31 is ensured, and The pump 9 is prevented from sucking air from the oil strainer 40.

As described above, the automatic transmission AT of the first embodiment includes an inner wall rib 32 for increasing the strength of the case around the shafts of the drive shafts 7 and 7, and an oil inlet 51 opened at an upper position of the inner wall rib 32. The structure provided with the return flow path 33 which returns a hydraulic oil (ATF) from the oil pan 30 to the oil pan 30 was employ | adopted.

Thus, as described above, the automatic transmission AT achieves the axial support strength performance, the breather performance and the inclined air intake prevention performance, which are required performances.

In the first embodiment, as the inner wall rib 32, the first inner wall rib connecting radially the mounting case portion 48 of the flow path plate 10 provided around the bearing boss 47 and the first shaft center C1. The structure which has 32a and the 2nd inner wall rib 32b which connects the bearing boss 47 and the case flange part 44 in the radial direction was employ | adopted.

That is, the installation case part 48 and the case flange part 44 of the flow path plate 10 are the parts with high rigidity among the transmission case 1. That is, the arm-shaped rib by the 1st inner wall rib 32a and the 2nd inner wall rib 32b was formed using the case part with high rigidity, and it was set as the countermeasure against torsional strength. Specifically, the rib shape was determined by considering the analysis of the static torsional stress and the relaxation of the stress concentration.

Therefore, the torsional support strength of the drive shafts 7 and 7 is improved by the first inner wall ribs 32a and the second inner wall ribs 32b in the shape of an arm shape, thereby suppressing noise and vibration.

[Slope Opening Action of Oil Inlet]

The reason why the oil inlet 51 into which the operating oil (ATF) flowed or scattered into the breather space is introduced into the inclined surface is explained.

First, from the viewpoint of the oil return action, when the oil inlet port 51 is provided on the horizontal surface, the suction flow rate is increased, but at the time of production, the oil return hole is in a deep position, so that the burr can not be removed. On the other hand, from the viewpoint of productivity, when the oil inlet 51 is provided on the vertical surface, the productivity is good, but the suction flow rate is reduced.

Therefore, in the first embodiment, the oil inlet 51 is opened on the inclined surface perpendicular to the visual direction when viewed from the inclined upper side toward the differential gear inner wall 46 as shown in FIG.

Therefore, productivity is ensured as if a burr can be removed by inserting a tool or rounding can be performed. In addition, the suction flow rate can be increased by securing the vertical projection area of the oil inlet 51. That is, by making the oil inlet 51 into the opening to the inclined surface, it is possible to secure both satisfactory productivity and increase the suction flow rate.

[Oil Level Management Action of Oil]

As described above, when the hydraulic oil ATF is moved or scattered to the breather space, it is necessary to continue the flow of guiding the hydraulic oil to the return flow passage 33 to maintain the oil level to maintain the oil level. Hereinafter, the oil level management action of hydraulic oil (ATF) in the first embodiment reflecting this will be described.

First, the flow of hydraulic oil ATF by gear scraping is demonstrated using FIG.

During the flow of hydraulic oil (ATF) due to gear scraping, the hydraulic oil (ATF) scraped in the right direction along the differential final gear 24 is engaged by the engagement of the idler final gear 23 and the differential final gear 24. As shown by the arrow D direction of FIG. 6, by the rectification | action action by the 1st rectifying surface 35a, a direction falls from an upward direction to an oblique downward direction, and falls.

During the flow of hydraulic oil (ATF) due to gear scraping, the hydraulic fluid (ATF) scraped in the right direction along the output gear 18 is engaged with the idler gear (AF) due to the engagement of the output gear 18 and the idler gear 19. It is guided in the left turning direction along the outer circumference of 19). And as shown by the arrow E direction of FIG. 6, it falls down by the rectifying action by the 2nd rectifying surface 35b.

Then, the hydraulic fluid ATF dropped from both sides is collected and received at the end position of the approach guide surface 34, and the collected hydraulic oil ATF is smoothly flowed in the right direction of FIG. 6 with little resistance along the approach guide surface 34. FIG. Guide to oil inlet 51.

The flow of hydraulic oil ATF by acceleration / deceleration G will be described. When the high postal force (G) acts during rapid start or sudden braking, or when the high transverse (G) acts when turning, the hydraulic oil (ATF) stored in the case chamber 36 receives these accelerations and decelerations (G). Then, it moves upward toward the breather space along the inner wall of the case. The hydraulic fluid (ATF) moved upwards falls downward according to gravity, but the hydraulic fluid (ATF) dropped on the approach guide surface 34 among the dropped hydraulic fluids (ATF) has a low resistance and smoothly. 6 flows to the right direction to guide the oil inlet 51.

In this way, the hydraulic oil (ATF) scraped up by the gear scraping up or the hydraulic oil (ATF) moved upward by receiving the acceleration / deceleration (G) also has an oil inlet (51) or an oil inlet (from the approach guide surface 34). 51). For this reason, the flow which guides hydraulic oil ATF to the return flow path 33 continues while driving, the fluctuation range of an effective flow volume can be suppressed, and the oil level management with high precision which maintains a surface level can be performed.

As described above, in the first embodiment, in the differential gear inner wall 46 between the second shaft center C2 and the third shaft center C3, hydraulic oil ATF falling from the breather space is received, and the oil inlet 51 is collected. The structure which forms the approach guide surface 34 which leads to () is employ | adopted.

Therefore, the flow which collects and accommodates the hydraulic fluid (ATF) which dropped from the breather space, guides it to the oil inflow port 51 smoothly without resistance, and the flow which guides hydraulic oil (ATF) to the return flow path 33 is continued. .

In the first embodiment, a configuration is provided in the transmission case 1 including a rectifying portion 35 having a first rectifying surface 35a and a second rectifying surface 35b.

And the hydraulic oil ATF which scrapes and moves by the rotation of the differential final gear 24 is rectified by the 1st rectifying surface 35a toward the approach guide surface 34. As shown in FIG. The hydraulic oil ATF moving by the rotation of the idler gear 19 is rectified by the second rectifying surface 35b so as to face the approach guide surface 34.

Therefore, the flow of hydraulic oil (ATF) due to the scraping up of the hydraulic fluid (ATF) to effectively guide the approach guide surface 34, and flows in from the oil inlet 51 and returned to the oil pan chamber 37 Flow rate is secured.

Next, the effect will be described.

In the automatic transmission AT of the first embodiment, the following effects can be obtained.

(1) a transmission case (1) in which hydraulic oil (ATF) is stored to make a breather space in which an upper space is communicated with the outside air from the oil level;

A transmission shaft (transmission input shaft 4, transmission output shaft 5) having a first shaft center C1 supported by the transmission case 1 and having a transmission mechanism for shifting the input rotation speed;

And having a second shaft center C2 having an idler gear 19 which is case-supported at a position above the first shaft center C1 and engaged with the output gear 18 provided on the transmission shaft (transmission output shaft 5). With idler shaft (6),

A third having a differential final gear 24 that is case-supported at a position lower than the first shaft center C1 and the second shaft center C2 and engaged with the idler final gear 23 provided on the idler shaft 6. A final shaft (drive shafts 7 and 7) having shaft center C3,

An oil pan (30) installed in the transmission case (1) and storing the hydraulic oil (ATF) and having an oil strainer (40) set at an inlet (39) of an oil pump (9);

The final shaft is formed in the differential gear inner wall 46 along the differential final gear 24 of the transmission case 1 in the wall region between the first shaft center C1 and the third shaft center C3. Inner wall ribs 32 for increasing the strength around the shaft of the drive shafts 7 and 7,

An oil inlet 51 is opened above the inner wall rib 32 to provide a return flow path 33 for returning the hydraulic oil ATF from the oil inlet 51 to the oil pan 30. .

As a result, the axial support strength performance, the breather performance, and the inclined air intake prevention performance, which are the unit required performances of the automatic transmission AT, can be achieved together.

(2) The return flow path 33 opened the oil inlet 51 on an inclined surface perpendicular to the visual direction when viewed from the inclined upper side toward the differential gear inner wall 46.

For this reason, in addition to the effect of (1), by making the oil inlet 51 into the opening to the inclined surface, it is possible to secure both satisfactory productivity and increase the suction flow rate.

(3) The return flow path 33 is a lower position of the second shaft center C2 and opens the oil inlet 51 at an upper position of the inner wall rib 32, and the second shaft center C2 and the Approach guide surface for receiving the hydraulic oil (ATF) falling from the breather space on the differential gear inner wall 46 between the third shaft center (C3), and collects the hydraulic oil (ATF) to guide the oil inlet 51 ( 34).

For this reason, in addition to the effect of (1) or (2), it shows the guide effect | action which collects and accommodates the hydraulic fluid (ATF) which fell from the breather space, and guides it to the oil inflow port 51 smoothly without resistance, 33) can continue the flow leading to hydraulic fluid (ATF).

(4) The hydraulic oil (ATF) formed in the transmission case 1, having a shape corresponding to the outer shape of the differential final gear 24, and scraped and moved by the rotation of the differential final gear 24 is the approach. The first rectifying surface 35a rectified to face the guide surface 34 and the hydraulic oil ATF which has a shape corresponding to the outer shape of the idler gear 19 and moves by the rotation of the idler gear 19 are described above. And a rectifying portion 35 having a second rectifying surface 35b commutated to face the approach guide surface 34.

For this reason, in addition to the effect of (3), it shows the commutation effect | action which guides the flow of hydraulic oil (ATF) by gear scraping up to the approach guide surface 34 effectively, flows in from the oil inlet port 51, It is possible to secure the flow rate of the hydraulic oil (ATF) returned to 37).

(5) The inner wall rib 32 is an installation case portion of the flow path plate 10 provided around the bearing boss 47 of the final shaft (drive shafts 7 and 7) and the first shaft center C1 ( The first inner wall rib 32a connecting the 48 in the radial direction, the bearing boss 47 of the final shaft (drive shafts 7 and 7), and the case flange portion 44 of the transmission case 1 It has the 2nd inner wall rib 32b connected in a radial direction.

For this reason, in addition to the effects of (1) to (4), the final shaft (drive shafts 7 and 7) is formed by the first inner wall ribs 32a and the second inner wall ribs 32b which are arranged in the shape of an arm. Torsional support strength can be improved, and noise and vibration can be suppressed.

(6) The shift mechanism includes a plurality of planetary gears (first planetary gear 11, second planetary gear 12) and a plurality of shifting friction elements (first clutch 13, second clutch 14, first). 3 clutch 15, 1st brake 16, 2nd brake 17], It is a stepped transmission mechanism which achieves the gear shift stage (4 forward speeds) of an oil stage,

The transmission shaft is a transmission input shaft 4 and a transmission output shaft 5 disposed on the same first shaft center C1.

For this reason, in addition to the effects of (1) to (5), in the automatic transmission AT having a parallel three-axis structure and achieving a step shift stage, the support strength performance and the breather of the drive shafts 7 and 7 are achieved. Performance and anti-slope air intake can be achieved together.

As mentioned above, although the automatic transmission of this invention was demonstrated based on 1st Example, the specific structure is not limited to this 1st Example and does not deviate from the summary of invention regarding each claim of a claim. As long as design changes or additions are allowed.

In the first embodiment, the oil inlet 51 is opened below the second shaft center C2 and is located above the inner wall rib 32, and the return flow passage 33 is opened from the open oil inlet 51. An example is used as the oil hole to return to (37). However, the oil inlet is not limited to the opening position of the first embodiment as long as the oil inlet is opened to the upper position of the inner wall rib 32. For example, the oil inlet may be opened at a position effective for returning the working oil moved or scattered to the breather space to the oil pan chamber, corresponding to the case inner wall shape.

In the first embodiment, an example of the inner wall ribs 32 by the first inner wall ribs 32a and the second inner wall ribs 32b in the shape of an arm shape is shown. However, the specific shape and configuration of the inner wall ribs are not limited to the first embodiment, and various shapes and configurations may be adopted depending on the strength improvement request around the final axis.

In the first embodiment, an example is applied to an automatic transmission AT that achieves a four-speed forward speed. However, the present invention can be applied to an automatic transmission that achieves a shift speed other than the fourth forward speed (for example, five forward speeds or more), and can be applied to an automatic transmission (= stepless transmission) that achieves a stepless speed ratio.

1: transmission case
4: transmission input shaft (shift shaft)
5: transmission output shaft (shift shaft)
6: idler shaft
7, 7: drive shaft (final shaft)
9: oil pump
10: Euro plate
11: first planetary gear (planetary gear)
12: 2nd planetary gear (planetary gear)
13: first clutch (shifting friction element)
14: second clutch (shifting friction element)
15: third clutch (shifting friction element)
16: first brake (variable friction element)
17: 2nd brake (shift friction element)
18: output gear
19: idler gear
23: idler final gear
24: Differential Final Gear
30: oil pan
31: communicating oil holes
32: inner wall rib
32a: first inner wall rib
32b: second inner wall rib
33: return flow path
34: approach guide surface
35: rectifier
35a: first rectifying surface
35b: second commutation surface
36: case seal
37: oil pan seal
39: suction port
40: oil strainer
44: case flange
46: differential gear inner wall
47: bearing boss
48: installation case
51: oil inlet
C1: first axis
C2: second axis
C3: 3rd axis
ATF: working oil
W: stop oil surface

Claims (6)

A transmission case in which operating oil is stored and makes a breather space in which a space above the oil surface communicates with the outside air,
A transmission shaft supported by the transmission case and having a first shaft center having a transmission mechanism for shifting an input rotational speed;
An idler shaft having a second shaft center case-supported at a position above the first shaft center and having an idler gear engaged with the output gear provided on the transmission shaft;
A final shaft having a third shaft core having a differential final gear case-supported at a position lower than the first shaft core and the second shaft core and engaged with an idler final gear provided on the idler shaft;
An oil pan installed in the transmission case and storing the working oil and having an oil strainer set at an inlet of an oil pump;
An inner wall rib formed on an inner wall of the differential gear according to the differential final gear of the transmission case to increase the strength of the case around the axis of the final shaft in the wall region between the first and third shaft cores;
And an oil inlet opening at an upper position of the inner wall rib to return the hydraulic oil to the oil pan from the oil inlet. The automatic transmission according to claim 1, wherein the return flow path opens the oil inlet on an inclined surface perpendicular to the visual direction when viewed from the inclined upper side toward the differential gear inner wall. 3. The differential gear according to claim 1, wherein the return flow path is a lower position of the second shaft center and opens the oil inlet at an upper position of the inner wall rib, and the differential gear between the second shaft center and the third shaft center. And an approach guide surface for receiving the hydraulic fluid falling from the breather space and collecting the hydraulic oil to guide the oil inlet to an inner wall. According to claim 3, The first case is formed in the transmission case, the shape according to the outer shape of the differential final gear, the hydraulic oil scraped up and moved by the rotation of the differential final gear is rectified to face the approach guide surface And a rectifying portion having a rectifying surface and a second rectifying surface having a shape conforming to the outer shape of the idler gear and rectifying the hydraulic fluid moving by the rotation of the idler gear toward the approach guide surface. Transmission. The said inner wall rib is a 1st inner wall rib which radially connects the bearing boss of the said final shaft and the installation case part of the flow path plate provided around the said 1st shaft center, and the bearing boss of the said final shaft. And a second inner wall rib connecting the case flange portion of the transmission case in a radial direction. The step shifting mechanism according to claim 1 or 2, wherein the shifting mechanism is a step shifting mechanism that achieves a shift stage of an oil phase by a plurality of planetary gears and a plurality of shifting friction elements,
And said transmission shaft is a transmission input shaft and a transmission output shaft disposed on the same first shaft center.

Images