Slave cylinder housing for disconnect clutch

Abstract

The invention relates to a slave cylinder housing (10) for a disconnect clutch (100), comprising an inner wall (11), an outer wall (12) and a base wall (13) interconnecting the inner wall (11) and the outer wall (12), where the inner wall (11), the outer wall (12) and the base wall (13) together delimit a pressure chamber (14), where the slave cylinder housing (10) has a cylindrical design about a longitudinal axis L, and where the inner wall (11), the outer wall (12) and the base wall (13) define a pressure chamber (14). The outer wall (12) has a plurality of inlet openings (12a, 12b, 12c) spaced apart from one another over a circumference, with a first inlet opening (12a) and a second inlet opening (12b) positioned diametrically opposite one another.

Description

Field of the Invention

[0001] The present invention relates to a slave cylinder housing for a clutch, in particular for a disengaging clutch in an electric motor vehicle or a motor vehicle with a hybrid drive. Background Art

[0002] As is known, a disengaging clutch, also known as a K0 clutch, is used to disconnect an electric motor from an internal combustion engine in a vehicle with a hybrid drive, or to change gears in a vehicle with an electric motor.

[0003] A slave cylinder, also abbreviated as "CSC" (concentric slave cylinder), is used to engage and disengage such a disengaging clutch. In a disengaging clutch, the proper functioning of the slave cylinder is of particular importance from a safety perspective.

[0004] The slave cylinder generally includes: a housing made of, for example, GF polymer or aluminum, a piston made of, for example, GF polymer accommodated in the housing, a release bearing on which the piston acts, and a groove seal ring made of, for example, EPDM or HNBR, depending on the fluid via which the slave cylinder is actuated. The groove seal ring can be seated on a groove seal ring carrier. The slave cylinder housing is usually mounted at a designated position on the transmission housing.

[0005] A channel for fluid supply is also formed in the transmission housing. The slave cylinder housing has an opening through which hydraulic fluid can flow into the slave cylinder housing and cause the piston to move in the axial direction relative to the housing axis. The high-pressure connection between the transmission housing and the slave cylinder housing is conventionally sealed by an O-ring.

[0006] However, it has been found that the combination of increased rotational speeds (>6000 rpm) and an angled clutch can lead to very large pressure fluctuations. These pressure fluctuations are introduced into the slave cylinder housing via the piston and then transmitted to the hydraulic fluid via the groove seal ring. The fluid flows from the inner pressure chamber into the outer pressure chamber and then into the high-pressure connection in the transmission housing. If the pressure control valve at the outlet of the pump injecting the hydraulic fluid detects excessive pressure, the pressure control valve opens to release the excess pressure. This behavior means that the vehicle cannot reach higher speeds when the internal combustion engine starts and the electric motor runs in parallel. Summary of the Invention

[0007] Accordingly, it is an object of the present invention to provide a slave cylinder housing for a disengaging clutch, using which pressure oscillations in the hydraulic system can be reduced.

[0008] According to the present invention, this object is achieved by a slave cylinder housing for a disengaging clutch according to claim 1, a housing unit according to claim 7, and a clutch unit according to claim 10. Preferred configurations are provided in the dependent claims.

[0009] The slave cylinder housing for a disengaging clutch has an inner wall, an outer wall, and a base wall interconnecting the inner wall and the outer wall, wherein the inner wall, the outer wall, and the base wall jointly define a pressure chamber, wherein the slave cylinder housing has a cylindrical design about a longitudinal axis L, and wherein the outer wall has a plurality of inlet openings spaced apart from each other in the circumferential direction. According to the invention, a first inlet opening and a second inlet opening are positioned diametrically opposite each other.

[0010] The inner wall, the outer wall, and the base wall form a pressure chamber that opens to the side opposite the base wall to accommodate a piston that can slide axially in the pressure chamber under the action of hydraulic fluid to axially displace a release bearing connected to the disengaging clutch.

[0011] The first inlet opening and the second inlet opening are for allowing hydraulic fluid to flow into and out of the pressure chamber defined in the slave cylinder housing. The hydraulic fluid flowing through the diametrically opposite inlet openings influences each other. This significantly reduces the resulting pressure oscillations.

[0012] In particular, at least three inlet openings can be provided in the outer wall of the slave cylinder housing, wherein a third inlet opening is formed centrally in the circumferential direction between the first inlet opening and the second inlet opening. When viewed in a sectional view perpendicular to the longitudinal axis L, when the third inlet opening is at the 12 o'clock position, the first inlet opening and the second inlet opening are approximately at the 3 o'clock position and the 9 o'clock position, respectively. In other words, the first inlet opening and the third inlet opening form an angle of approximately 90° with each other, and the second inlet opening and the third inlet opening also form an angle of approximately 90° with each other.

[0013] When used in a disengaging clutch unit, the slave cylinder housing is installed in another housing such as a transmission housing that at least partially surrounds the slave cylinder housing. This forms an outer pressure chamber between the slave cylinder housing and the other housing. The hydraulic fluid supplied to the pressure chamber of the slave cylinder housing can escape to the outside via the inlet openings of the slave cylinder housing and enter the outer pressure chamber.

[0014] If, when using the slave cylinder housing, the piston accommodated in the slave cylinder housing undergoes a wobbling movement due to the angled clutch rotating in the powertrain of a motor vehicle, pressure oscillations are generated in the hydraulic fluid and a very fast fluid movement within the slave cylinder housing results. Thus, the hydraulic fluid is pushed out of the pressure chamber of the slave cylinder housing and enters the outer pressure chamber via the inlet opening. When the hydraulic fluid is pushed into the opening at the 9 o'clock position, excessive pressure is generated here. At the same time, a vacuum is formed on the other side at the opening at the 3 o'clock position. These two pressures influence each other greatly, such that the pressure fluctuations generated are very small. Therefore, it is particularly advantageous to form the inlet opening at the aforementioned position.

[0015] It is also very advantageous if the first inlet opening and the second inlet opening each have a larger surface area O compared to the third inlet opening. In the context of the present invention, the term "surface area O" refers to the surface on the outer wall of the slave cylinder housing that is cut by the respective inlet opening.

[0016] The smaller surface area of the third inlet opening is due to its function: on the one hand, the third inlet opening serves to supply hydraulic fluid from the reservoir into the pressure chamber of the slave cylinder housing to actuate the disengaging clutch. On the other hand, the third inlet opening also acts as a ventilation opening. The third inlet opening should not be too large such that high pressure fluctuations are not generated in the hydraulic fluid at this position. On the other hand, the first inlet opening and the second inlet opening, which are opposite each other, must both be large enough such that the opening and closing times required for the disengaging clutch can be maintained.

[0017] In this context, it has proven to be particularly advantageous if the first inlet opening and the second inlet opening each have a surface area O that is at least twice as large as that of the third inlet opening, in particular at least three times as large as that of the third inlet opening.

[0018] For symmetry considerations, the first inlet opening and the second inlet opening can each have an equal-sized surface area O. This ensures that any pressure fluctuations occurring in the hydraulic fluid during the aforementioned wobbling movement of the piston can be compensated to a large extent.

[0019] According to another advantageous embodiment, the inlet openings in the outer wall can each be formed adjacent to the base wall. This design has proven to be particularly useful in terms of flow.

[0020] The invention also relates to a housing unit for a disengaging clutch, the housing unit having a slave cylinder housing and a transmission housing according to one of the above-described embodiments, wherein the slave cylinder housing and the transmission housing are arranged concentrically with each other, and the slave cylinder housing is at least partially received in the transmission housing, and wherein the transmission housing has an outer wall opening. In this way, the transmission housing together with the outer wall of the slave cylinder housing or a part thereof can form an outer pressure chamber, which is connected to the pressure chamber of the slave cylinder housing via an inlet opening, i.e., in a fluid-conducting connection. Preferably, both the slave cylinder housing and the transmission housing are of a cylindrical design and are at least partially open towards one end face. The outer wall of the slave cylinder housing can be sealed relative to the transmission housing via an annular seal. In particular, the two housings can have a common longitudinal axis L, which coincides with the longitudinal axis of an electric motor for a motor vehicle.

[0021] The outer wall opening of the transmission housing is preferably aligned with a third inlet opening of the outer wall of the slave cylinder housing. This means that hydraulic fluid can be directly introduced into the pressure chamber of the slave cylinder housing through the outer wall opening via the third inlet opening of the slave cylinder housing.

[0022] According to one embodiment, the diameter D of the outer wall opening of the transmission housing in a cross-section perpendicular to the longitudinal axis L is equal to the diameter d of the third inlet opening of the slave cylinder housing in a cross-section perpendicular to the longitudinal axis L.

[0023] A clutch unit according to an embodiment of the invention can include a disengaging clutch and a housing unit according to one of the foregoing embodiments. In particular, the disengaging clutch and the slave cylinder housing are interconnected via a release bearing, and when hydraulic fluid is delivered into the pressure chamber of the slave cylinder housing, the release bearing is acted upon by a piston received in the pressure chamber of the slave cylinder housing. Description of the Drawings

[0024] The invention will now be described in more detail with reference to non-limiting exemplary embodiments based on the drawings.

[0025] In the drawings:

[0026] Figure 1 A schematic view of a hybrid drive device for a motor vehicle to which the invention can be applied is shown;

[0027] Figure 2a 、 Figure 2b A longitudinal sectional view and a cross-sectional view through a housing unit from the prior art are shown;

[0028] Figure 2c 、 Figure 2dshows a graph which shows the characteristics of the hydraulic pressure in a straight disengaging clutch and an angled disengaging clutch according to the prior art;

[0029] Figure 3 shows Figure 3 a detailed view of an embodiment of a;

[0030] Figure 4 shows a plan view of a holding clip according to an embodiment of the present invention; and

[0031] Figure 5a and Figure 5b Detailed Description

[0032] Figure 1 shows a schematic view of a part of a hybrid drive device for a motor vehicle, the hybrid drive device being generally identified by the reference numeral 1000. The hybrid drive device 1000 includes a clutch unit 100 having a disengaging clutch 30 and a slave cylinder housing 10 which is received in a transmission housing 20. An outer wall opening 21a is formed in an outer wall 21 of the transmission housing for supplying a hydraulic fluid 200 from a reservoir 300 to the slave cylinder housing 10. In the illustrated embodiment, a so-called reservoir area 201 can also be seen which is formed on the surface of the hydraulic fluid 200 in the reservoir 300.

[0033] The slave cylinder housing 10 is connected via a release bearing 60 to a spring device which can be designed as a disc spring 50, which in turn acts on the disengaging clutch 30 as shown. Thus, when the hydraulic fluid 200 is conveyed from the reservoir 300 to the transmission housing 20 via a pump 90, for example, a check valve 80 can be arranged between the pump 90 and the transmission housing 20 to prevent reverse flow as shown, the hydraulic fluid 200 can be pumped via the outer wall opening 21a of the outer wall 21 of the transmission housing to the slave cylinder housing 10 to actuate the disengaging clutch 30.

[0034] Here, both the slave cylinder housing 10 and the transmission housing 20 have a cylindrical design and are arranged about a common longitudinal axis L of the slave cylinder housing 10. It should be appreciated that the electric motor 40 and the disengaging clutch 30 can also be concentrically positioned about the longitudinal axis L. In the illustrated embodiment, the transmission housing 20 and the slave cylinder housing 10 are axially offset with respect to the electric motor 40 and the disengaging clutch 30 about the longitudinal axis L. A further valve 70, which can be a pressure control valve 70, is connected in parallel here to the pump 90 and the check valve 80 and also leads to the reservoir 300 for the hydraulic fluid 200.

[0035] This arrangement of the components of the hybrid drive device 1000 can correspond to the prior art. Now, reference will be made to Figure 2a and Figure 2b to describe the housing unit 1' according to the prior art in more detail, wherein Figure 2a the representation shows a longitudinal sectional view along the longitudinal axis L, while Figure 2b the representation shows a sectional view perpendicular to the longitudinal axis along the plane A - A of Figure 2a .

[0036] The housing unit 1' includes a driven cylinder housing 10 and a transmission housing 20 arranged concentrically with each other. A pressure chamber 14 is formed in the driven cylinder housing 10, and here the pressure chamber is bounded on the right by the base wall 13. An outer wall opening 21a can be seen in the transmission housing 20, and here the outer wall opening extends perpendicular to the longitudinal axis L. An outer pressure chamber 24 is formed between the inner wall 22 of the transmission housing and the driven cylinder housing 10, and the outer pressure chamber is sealed by an O - ring 25 of the base wall 23 of the transmission housing. A piston 15 is accommodated in the pressure chamber 14 of the driven cylinder housing 10, and the piston can slide parallel to the longitudinal axis L when hydraulic fluid 200 is supplied into the pressure chamber 14 through the outer wall opening 21a of the transmission housing 20. It can be seen from here that the piston 15 can be sealed relative to the pressure chamber 14 by a groove seal ring 26, and the groove seal ring can be located on a seal ring carrier.

[0037] In the outer wall 12 of the driven cylinder housing 10, inlet openings 12a', 12b', 12c' are provided to fluid - conductively connect the inner pressure chamber 14 and the outer pressure chamber 24.

[0038] Now, reference will be made to Figure 2c and Figure 2d to illustrate the disadvantages of the housing unit 1' of Figure 2c according to the prior art. If the disengaging clutch 30 is straight, as shown in the curve graph of Figure 2c , the pressure fluctuations of the hydraulic fluid 200 in the clutch unit 100 remain within certain limits. The curve graph shows the relationship between the hydraulic pressure in the transmission housing and the angle. On the other hand, if the disengaging clutch 30 is angled, as in the case of the curve graph in Figure 2d , high pressure fluctuations will occur in the transmission housing. In this case, the valve 70 (see Figure 1 ), which is a pressure control valve, will open, thereby releasing pressure from the housing.

[0039] Figure 3 shows a cross - section perpendicular to the longitudinal axis L of a housing unit 1 according to an embodiment of the present invention (see Figure 1)。Similar to the housing unit 1' of the prior art, the housing unit 1 includes a slave cylinder housing 10 and a transmission housing 20. Among them, the transmission housing 20 includes a transmission housing outer wall 21 having an outer wall opening 21a, a transmission housing inner wall 22, and a transmission housing base wall 23. Here, similarly, the slave cylinder housing 10 includes an inner wall 11 and an outer wall 12, and a pressure chamber 14 is formed between the inner wall and the outer wall. An outer pressure chamber 24 is formed between the outer wall 12 of the slave cylinder housing 10 and the inner wall 22 of the transmission housing, and is connected to the pressure chamber 14 via a first inlet opening 12a, a second inlet opening 12b, and a third inlet opening 12c in the outer wall 12 of the slave cylinder housing 10.

[0040] Compared with the prior art, in the embodiment of the present invention, the first inlet opening 12a and the second inlet opening 12b are positioned diametrically opposite to each other on the longitudinal axis L (see Figure 1 ). The third inlet opening 12c is equidistantly spaced from each of the first inlet opening 12a and the second inlet opening 12b, that is, in this case, spaced 90° in the circumferential direction of the slave cylinder housing 10. Although the first inlet opening 12a and the second inlet opening 12b have the same surface area O here, which is represented by the double arrow of Figure 3 as the cross-section of the surface area O, this surface area O is significantly larger than the surface area of the third inlet opening 12c. This can greatly reduce the pressure oscillation of the hydraulic fluid 200 in the pressure chamber 14. In addition, the third inlet opening 12c of the slave cylinder housing 10 is aligned with the outer wall opening 21a of the transmission housing 20, and the diameter d of the third inlet opening 12c is equal to the diameter D of the outer wall opening 21a, in each case, observed from the cross-section perpendicular to the longitudinal axis L of the housing unit 1 shown here.

[0041] As mentioned above, the pressure oscillation generated by the swinging movement of the piston 15 (see Figure 1 ) causes a very rapid fluid movement in the slave cylinder housing 10. This pressure oscillation is caused by rotating the angled disengaging clutch 30. The hydraulic fluid 200 is pushed out of the pressure chamber 14 and enters the outer pressure chamber 24. When the hydraulic fluid 200 is pressed into the first inlet opening (9 o'clock position in this figure), an excessive pressure will occur. At the same time, a vacuum is formed on the opposite side at the second inlet opening 12b (3 o'clock position). These two pressures affect each other, making the generated pressure fluctuations very small.

[0042] Figure 4 The pressure fluctuations at the second inlet opening 12b are shown by solid lines, and the pressure fluctuations at the first inlet opening 12a are shown by dashed lines. The numerical axis on the right side of this figure indicates the time process, while the vertical numerical axis indicates the pressure. It can be seen that the pressure fluctuations cancel each other out.

[0043] In contrast, Figure 5a and Figure 5b shows the functional relationship between the pressure fluctuation and the angle when the disengaging clutch 30 is in an angled position, where, Figure 5a shows the pressure fluctuation in the slave cylinder housing 10 of the prior art, while Figure 5b shows the functional relationship between the pressure fluctuation and the angular position in the slave cylinder housing 10 according to an embodiment of the present invention. It can be seen here that the present invention can significantly reduce the pressure fluctuation.

[0044] List of Reference Numerals

[0045] 1’ Housing unit (prior art)

[0046] 1 Housing unit

[0047] 10 Slave cylinder housing

[0048] 11 Inner wall

[0049] 12 Outer wall

[0050] 12a First inlet opening

[0051] 12b Second inlet opening

[0052] 12c Third inlet opening

[0053] 13 Base wall

[0054] 14 Pressure chamber

[0055] 15 Piston

[0056] 20 Transmission housing

[0057] 21 Transmission housing outer wall

[0058] 21a Outer wall opening

[0059] 22 Transmission housing inner wall

[0060] 23 Transmission housing base wall

[0061] 24 Outer pressure chamber

[0062] 25 O-ring

[0063] 26 Groove seal ring

[0064] 30 Disengaging clutch

[0065] 40 Electric motor

[0066] 50 Disc spring

[0067] 60 Release bearing

[0068] 70 Valve

[0069] 80 Check Valve

[0070] 90 Pump

[0071] 100 Clutch Unit

[0072] 200 Hydraulic Fluid

[0073] 201 Storage Tank Area

[0074] 300 Reservoir

[0075] 1000 Hybrid Drive Unit

Claims

1. A slave cylinder housing (10) for a disengaging clutch (30), the slave cylinder housing having: An inner wall (11), an outer wall (12), and a base wall (13) interconnecting the inner wall (11) and the outer wall (12), wherein, The inner wall (11), the outer wall (12) and the base wall (13) together define a pressure chamber (14), wherein the slave cylinder housing (10) has a cylindrical design about a longitudinal axis L, and wherein the outer wall (12) has a plurality of inlet openings (12a, 12b, 12c) spaced apart from each other circumferentially. Characterized in that a first inlet opening (12a) and a second inlet opening (12b) are positioned diametrically opposite each other.

2. The slave cylinder housing (10) according to claim 1, characterized in that, At least three inlet openings (12a, 12b, 12c) are provided, wherein a third inlet opening (12c) is formed circumferentially centered between the first inlet opening (12a) and the second inlet opening (12b).

3. The slave cylinder housing (10) according to claim 1 or 2, characterized in that, The first inlet opening (12a) and the second inlet opening (12b) each have a larger surface area O than the third inlet opening (12c).

4. The slave cylinder housing (10) according to claim 3, characterized in that, The first inlet opening (12a) and the second inlet opening (12b) each have an equal-sized surface area O.

5. The slave cylinder housing (10) according to claim 3 or 4, characterized in that, The first inlet opening (12a) and the second inlet opening (12b) each have a surface area O that is at least twice as large as the third inlet opening (12c).

6. The slave cylinder housing (10) according to any one of the preceding claims, characterized in that, The inlet openings (12a, 12b, 12c) in the outer wall (12) are each formed adjacent to the base wall (13).

7. A housing unit (1) for a disengaging clutch (30), the housing unit having a slave cylinder housing (10) and a transmission housing (20) according to any one of the preceding claims, wherein, The slave cylinder housing (10) and the transmission housing (20) are arranged concentrically with each other, and the slave cylinder housing (10) is at least partially received in the transmission housing (20), and wherein the transmission housing (20) has an outer wall opening (21a).

8. The housing unit (1) according to claim 7 when referring back to claim 2, characterized in that, The outer wall opening (21a) of the transmission housing (20) is aligned with the third inlet opening (12c) of the outer wall (12) of the slave cylinder housing (10).

9. The housing unit (1) according to claim 8, characterized in that, The diameter D of the outer wall opening (21a) of the transmission housing (20) in a cross-section perpendicular to the longitudinal axis L is equal to the diameter d of the third inlet opening (12c) of the slave cylinder housing (20) in a cross-section perpendicular to the longitudinal axis L.

10. A clutch unit (100) having a disengaging clutch (30) and a housing unit (1) according to any one of claims 7 to 9.

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