manufacturing a stator support

The invention relates to a stator support for supporting a stator of a torque converter for an automatic transmission.

In an automatic transmission, such as a continuously variable transmission (CVT), there is provided a torque converter between the engine, such as an internal combustion engine or an electric motor, and the transmission. The torque converter is used to transfer rotating power from the engine to the driven load. The torque converter comprises a stator which is supported by a stator support. The torque converter also comprises a turbine that drives a turbine shaft.

A stator support typically comprises a stator support shaft having an axial bore therein for receiving the turbine shaft and has a stator support flange that radially extends outward from the stator support shaft to engage with a transmission housing to fixedly mount the stator support to the transmission housing and prevent rotation thereof with respect to the transmission housing.

The stator support is often used to supply hydraulic fluid, e.g. oil to various components of the transmission. Thereto, the stator support flange comprises at least one hydraulic fluid channel extending through the stator support flange.

There are various embodiments of stator supports known. For example, there is known to provide a separate stator support shaft and a separate stator support flange. The stator support flange is provided with an oil bore and the stator support shaft is provided with an oil bore as well. Since the stator support shaft and the stator support flange are two separate parts, when assembling, a fluid tight coupling is preferably obtained between the two parts such that the oil flows from the oil bore in the stator support flange to the oil bore in the stator support shaft. The oil can then flow as follows from the radially outer end of the stator support shaft to the radially inner end, then into the oil bore of the stator support shaft which ends in a space between the stator support shaft and the turbine shaft, further through another oil bore in the stator support shaft into the torque converter. This embodiment, as for example applied by

Jatco, provides for a relatively large axial length of the stator support shaft, and therefore, of the transmission. Also, there is a disadvantage in using two separate parts for the stator support for assembly.

In another example, there is a single piece stator support used, meaning that the stator shaft is integrated to the stator support. Then, the oil flow channel in the stator support flange ends radially outwardly of the stator support shaft. Thus, the oil flow continues radially outwardly of the stator support shaft between the stator support shaft and the impeller hub of the torque converter to then enter the torque converter. This results in complicated sealings and bearings for the oil channel, as well as a relatively large axial length of the stator support shaft, resulting in a relatively large axial length of the transmission as well.

It is an object of the invention to provide an improved stator support. In particular, it is an object of the invention to provide for a stator support having a reduced length and/or less complexity.

Thereto, the invention provides for a stator support for a stator of a torque converter comprising a stator support shaft having an axial bore therein for receiving a turbine shaft; a stator support flange integrally part of the stator support shaft and radially extending outward to engage with a transmission housing; wherein the stator support flange comprises at least one hydraulic fluid channel of which at least one of the hydraulic fluid channels is arranged for supplying hydraulic fluid to the torque converter, wherein the stator support shaft comprises at least one hydraulic fluid channel in fluid connection with the hydraulic fluid channel of the stator support flange for supplying hydraulic fluid to the torque converter; wherein the hydraulic fluid channel of the stator support shaft has an oblique orientation with respect to the hydraulic fluid channel of the stator support flange.

By providing a stator support with a stator support shaft and a stator support flange that are integrally part of the stator support, a single piece stator support is provided. This is advantageous for manufacturing, assembly, sealing etc.

By providing the hydraulic fluid channel in the stator support flange oblique with respect to the hydraulic fluid channel of the stator support shaft, a hydraulic fluid channel can be provided in the stator support without the need for complex and/or additional sealing. Also, by providing such an oblique fluid channel, the axial length of the stator support can be reduced and thus the overall length of the transmission may become shorter.

In the prior art, when providing a single piece stator support, it has been a problem of how to provide the hydraulic fluid channel through the single piece stator support. In the prior art single piece stator support, there is no fluid channel in the stator support shaft, the fluid flow is guided radially outwardly thereof, resulting in complex sealings, bearings, and a relatively long support shaft. The inventor now found that when an oblique fluid channel is provided in the stator support shaft, the fluid flow can be guided through the fluid channel in the stator support flange through the oblique channel in the stator support shaft and via a space between the axial bore of the stator support shaft and the turbine shaft to the torque converter. As such, complex sealings can be obviated, as well as,

advantageously, the axial length of the support shaft and thus of the transmission may become shorter.

Advantageously, the oblique channel in the stator support shaft extends through the whole stator support shaft, as seen in a direction along the central axis of the axial bore, so, from one side of the stator support shaft to the opposite side of the stator support shaft. This allows for easy manufacturing and drilling of the bore to provide the fluid channel in the support shaft. This means that, when seen in a direction along the axial bore of the stator support shaft, the bore for the fluid channel can be drilled from one side of the stator shaft, through the wall of the stator shaft, then through the opposite wall of the stator shaft for ending into the channel bore of the stator support flange. Drilling the bore through the whole stator support shaft provides a major advantage in providing a fluid channel in the single piece stator support.

In an advantageous embodiment, the stator support shaft comprises a further hydraulic fluid channel directed to the torque converter, such that, in use, the further hydraulic fluid channel ends in the torque converter. By providing such an additional, or a further, hydraulic fluid channel, in the stator support shaft, the flow of the hydraulic fluid can be as follows. The hydraulic fluid can flow, in a situation when applying pressure to the torque converter, from a radially outward end of the hydraulic fluid channel of the stator support flange to a radially inward end of the hydraulic fluid channel into the hydraulic fluid channel of the stator support shaft. Then the fluid flow continues in a space between an inner wall side of the support shaft and an outer wall side of the turbine shaft, towards the additional or further hydraulic channel that ends in the torque converter.

Preferably, this additional or further hydraulic fluid channel in the stator support shaft comprises multiple bores that are preferably

approximately equally distributed over the circumference of the stator support shaft. Then the hydraulic fluid can enter the torque converter at multiple locations distributed over the circumference of the stator support shaft.

It is in particular advantageous that, by drilling a through bore through the support shaft that the bore through the wall at one side of the support shaft ending in the channel of the support flange, this bore provides for a fluid connection with the hydraulic fluid channel of the support flange. Additionally, that the bore through the wall at the opposite side of the support shaft can provide for the further fluid channel that may connect to the torque converter.

Preferably, the angle of the oblique hydraulic fluid channel in the stator support shaft is between approximately 20 degrees and

approximately 80 degrees with respect to the hydraulic channel of the stator support flange, more preferably between approximately 30 degrees and approximately 70 degrees, more preferably around 45 degrees. So, an optimal angle can be obtained between a relatively short stator support and a smooth fluid flow channel.

The invention further relates to a mounting bracket, to a transmission comprising such a park lock unit, and to a method for assembling a park lock unit into a transmission.

Further advantageous embodiments are represented in the subclaims.

The invention will further be elucidated on the basis of exemplary embodiments which are represented in a drawing. The exemplary

embodiments are given by way of non-limitative illustration.

In the drawing:

Fig. 1 shows a schematic view of a cross- section through a plane comprising the 'apply' fluid flow channel of a turbine system comprising a stator support according to the invention;

Fig. 2 shows a detail of the stator support of Fig. 1;

Fig. 3 shows a schematic view of an axial cross- section of the stator support according to the invention;

Fig. 4 shows a schematic view of a radial cross-section of the stator support according to the invention;

Fig. 5 shows a schematic view through a plane comprising the 'release'-fluid flow channel of the turbine system of Fig. 1 Fig. 6 shows a schematic perspective view of the stator support connected to a transmission housing.

It is noted that the figures are only schematic representations of embodiments of the invention that are given by way of non-limiting example. In the figures, the same or corresponding parts are designated with the same reference numerals.

Figure 1 shows a schematic embodiment of a turbine system 1 comprising a torque converter 2, a turbine shaft 3, a stator support 4. The functioning of the torque converter 2 is well known, and will not be repeated here.

As known, the torque converter 2 receives input from an engine, such as an internal combustion engine and/or an electrical machine via a flexplate (not shown). A front alignment bush 5 is provided to align the torque converter with respect to a crankshaft. The torque converter 2 comprises at its inner side, a lock-up plate, a turbine and a stator. These components are not shown here, for reasons of simplicity. The turbine of the torque converter 2 is coupled via turbine hub 6 to the turbine shaft 3, which provides input to the transmission via shaft end 3a. The stator of the torque converter 2, is coupled via a one-way clutch and a stator hub 7 to the stator support 4.

The stator support 4 comprises a stator support shaft 8 and a stator support flange 9. According to the invention, the stator support 4 is a single piece component, meaning that the stator support flange 9 is integrally part to the stator support shaft 8.

The stator support shaft 8 has an axial bore 10 that is configured for receiving the turbine shaft 3. The axial bore 10 has a central axis C. The stator support shaft 8 extends axially in a direction along the central axis C. This is also shown in figure 3.

The stator support flange 9 extends radially outwardly with respect to the stator support shaft 8, in a direction transverse to the central axis C. The stator support flange 9 has a radially outward end 11a that is arranged for mounting to a transmission housing, shown in figure 6. By mounting the stator support flange 9 to the transmission housing 100, i.e. to the fixed world, the stator support 4 is kept stationary in the transmission housing 100. As such, due to the connection with the stator hub of the torque converter 2, the stator blades of the torque converter can be kept stationary as well, at least in a condition when the one-way clutch, that provides for the connection between the stator blades and the stator hub is engaged. In the embodiment shown in figure 6, the stator support 4 is connected to the transmission housing 100 by means of bolts 101. Here, eight bolts 101 are used, but more or less bolts, or other connection means, e.g. welding or press-fitting or clamping or screwing, etc. may be used.

At a radially outer side of the stator support shaft 8, a flange 21a of an impeller hub 21 of the torque converter 2 is bearingly supported on the stator support shaft 8 by bearing bushes 21b. The impeller hub 21 further drives an oil pump drive system sprocket 22 for driving an oil pump. The functioning thereof is well known and will not be elaborated further.

The stator support flange 9 comprises at least one hydraulic fluid channel to supply hydraulic fluid to components of the transmission.

Usually, there are multiple hydraulic fluid channels, arranged for supplying hydraulic fluid to multiple components of the transmission. Also, the stator support shaft 8 comprises at least one hydraulic fluid channel to supply hydraulic fluid. Advantageously, the hydraulic fluid channels of the stator support shaft 8 and the stator support flange 9 are in fluid connection with each other to supply hydraulic fluid to the respective component of the transmission.

At least one of these hydraulic fluid channels of the stator support 4 is arranged for supplying hydraulic fluid to the torque converter 2. There is provided a fluid channel 12 for the 'apply'-mode of the torque converter in which the lock-up plate of the torque converter 2 is locked to friction surface on an impeller of the torque converter 2. In this 'apply'-mode, the hydraulic fluid is applied at relatively high pressure. There is a fluid flow channel 12a extending through the stator support shaft 9 and a fluid flow channel 12b in the stator support shaft 8. Preferably, the fluid flow channels 12a, 12b are in fluid connection with each other. In figure 1, the 'apply'-fluid flow channel is shown, because the cross- section of the stator support 4 is shown in a plane through the 'apply'-fluid flow channel 12a.

Additionally, the stator support 4 comprises a fluid flow channel 13 for the 'release'-mode of the torque converter. In the 'release'-mode of the torque converter 2, the lock-up plate is released and pushed away from the friction surfaces. In the 'release'-mode, the hydraulic fluid is applied with a relatively large flow to push the lock-up plate away. There is a fluid flow channel 13a extending through the stator support flange 9 and a fluid flow channel 13b in the stator support shaft 8. Preferably, the fluid flow channel 13 are in fluid connection with each other. In figure 5, the 'release'-fluid flow channel 13 is shown, because the cross- section of the stator support 4 is shown in a plane through the 'release'-fluid flow channel 13. In figure 4, a cross-section of the stator shaft 8 is given showing multiple fluid flow channels amongst which the 'apply'-fluid flow channel 12a and the 'release'- fluid flow channel 13a. The 'release' fluid flow channel 13 ends in the turbine shaft 3, in which a bore 30 is provided that is fluidly connected to the channel 13 of the stator support 4 at one end and to the torque converter 2 at another end.

According to the invention, the fluid flow channel 12b in the stator support shaft 8 has an oblique orientation with respect to the fluid flow channel 12a in the stator support flange 9, as can be seen in figure 1 or figure 2. The angle a between the fluid flow channel 12b and the fluid flow channel 12a, is approximately between 20 degrees and 80 degrees, preferably between approximately 30 degrees and approximately 70 degrees, more preferably around 45 degrees. The apply outlet, via channels 15 and 14b2, preferably have a predetermined axial location, such that the apply flow can enter the torque converter. From this location, the bore 14b can be drilled oblique towards the radially drilled bore 14a of the stator support flange 9.

The fluid flow channel 12a is provided of a bore 14a extending in the stator support flange 9 between the radially inward end lib and the radially outward end 11a. The fluid flow channel 12b is provided of a bore 14b, which advantageously, extends from one side 8a of the stator support shaft 8 to another side 8b of the stator support shaft 8, when seen in a direction along the central axis C. In other words, the bore 14b forming the fluid flow channel 12b extends through the whole stator support shaft 8, as can be seen e.g. in figure 1, 2 or 3. The bore 14b is thus, according to the invention, oblique oriented with respect to the bore 14a. The angle a between the bores 14b, 14a, and therefore, between the channels 12b, 12a, is preferably the angle between the respective central axes of the bores 14b, 14a, and thus of the channels 12b, 12a.

By providing the bore 14b through the whole stator support shaft 8, the bore can be easily drilled from one side 8a of the stator support shaft 8 in a drilling direction B towards the bore 14a and until the bore 14b ends in the bore 14a to provide for a fluid connection between the fluid flow

channels 12b and 12a. As such, the bore 14b comprises two parts, a first part 14bl that ends in the bore 14a and a second part 14b2 that ends in the torque converter. By providing such an oblique fluid flow channel 12b in the stator support shaft 8 in a single piece stator support 4, a relatively short stator support shaft 8 can be provided while additionally the advantages of a single piece stator support, e.g. simple sealing and/or simple connection to the torque converter can be maintained.

By providing such an oblique fluid flow channel 12b in the stator support shaft 8, the axial length of the stator support shaft 8 may become shorter. In particular, the length A between the flange 21a of the impeller hub 21 and an end 8c of the stator support shaft 8 that is arranged for receiving a thrust bearing 23 to bearingly support a flange 3b of the turbine shaft 3. This length A determines a built-in axial dimension and the shorter this length A, the shorter the transmission can become. A relatively short transmission is advantageous for assembly and build-in purposes.

Advantageously, the stator support shaft 8 comprises a further fluid channel 15 that is directed towards the torque converter 2, and, when assembled, ends in the torque converter 2. Advantageously, the channel 15 comprises multiple bore, of which bore 14b2 is in this embodiment already one bore. Further bores 15a, 15b can be arranged equally spaced over the circumference of the stator support shaft 8. For example, when four bores are provided, they can be equidistantly spaced over an angle of

approximately 90 degrees, as can e.g. be seen in figure 3. Preferably, the angle of the channel 15 with respect to a central axis of the channel 12a is the same or similar as the angle a of the channel 12b with respect to the central axis of the channel 12a.

The bore 14b2 may be machined near an end 8e of the support shaft 8. Preferably the machining of the bore 14b2 is not applied over a length 8f of the stator support shaft 8, as this length is preferably used to support the bearing bush 21b. Also, is the apply channel would leak, then the apply channel hole is outside of the bearing bush support area 8f, since the bearing bush 21b also provides for sealing. The closer the bore 14b2 starts to the bearing bush support area 8f, the angle alpha can become smaller, which may be advantageous for the apply flow. Then, the apply flow may not be disturbed too much. In addition, the apply bore 14bl preferably allows sufficient space available for a landing area L of the sealing ring 140. that seals the apply chamber 110 from the release chamber 120. The landing area L may about approximately 1— 4 mm, preferably about approximately 2 mm. In 'apply'-mode, hydraulic fluid is applied via an opening 16, from a hydraulic manifold via a channel in the transmission housing to the opening 16, into the fluid flow channel 12a and flows radially inwardly to the fluid flow channel 12b. Then, the fluid flows in an apply chamber llObetween a wall 17 of the axial bore 10 and an outer wall 18 of the turbine shaft 3. This apply chamber 110 is provided due to a recess in the turbine shaft 3 over an axial length corresponding with an axial distance between channels 12b and 15 of the stator support shaft 4. The fluid then continues into the bores 15a, 15b, 14b2, 15c of the channel 15 into the torque converter 2 via an opening 19a between the impeller 21 and the one-way clutch 7. The fluid leaves the torque converter 2 via an opening 19b between the impeller 21 and the turbine hub 6 and enters a bore 30 of the turbine shaft 3 that is in fluid connection with the fluid flow channel 13 of the stator support flange 9.

In 'release'-mode, the fluid flow enters the fluid flow channel 13 via opening 31 through the fluid flow channel 13 through the bore 30 of the turbine shaft 3. Then, the fluid enters the torque converter via the opening 19b and leaves the torque converter 2 via opening 19a to enter into the channel 15 and continuing via a release chamber 120 formed between walls 17 and 18 of the axial bore 10 and of the turbine shaft 3 respectively at the position of the release channel 13. Via the inclined bore 14b the fluid goes into the bore 14a to leave the stator support via opening 16.

Further, as can be seen in figure 1 and figure 2, a primary pressure chamber 130 is provided between the outer wall 17 of the axial bore and a recess in the turbine shaft 3. Fluid flows through this chamber 130 when the variator of the transmission is being pressurized. This is further not explained in this disclosure.

Between the subsequent chamber 110, 120, 130, sealing rings 140 are provided to separate the different hydraulic fluid delivery channels 12, 13, and e.g. a channel for the primary pressure, using the turbine shaft 3 and the stator support 4 on their route. In the above, the oblique channel in the stator support shaft 8 is explained with respect to the fluid flow channels supplying the torque converter. It may be understood, that also other fluid flow channels in the stator support shaft can be embodied as inclined or oblique channels.

For the purpose of clarity and a concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include

embodiments having combinations of all or some of the features described. It may be understood that the embodiments shown have the same or similar components, apart from where they are described as being different.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words 'a' and 'an' shall not be construed as limited to 'only one', but instead are used to mean 'at least one', and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to an advantage.

Many variants will be apparent to the person skilled in the art. All variants are understood to be comprised within the scope of the invention defined in the following claims.