阅读说明：本技术 用于液压或气动离合器致动的中央致动器 (Central actuator for hydraulic or pneumatic clutch actuation ) 是由 J.尼普 于 2019-06-20 设计创作，主要内容包括：本发明涉及一种用于液压或气动离合器致动的中央致动器(10),具有缸壳体(12),所述缸壳体(12)具有至少一个由塑料制成的缸壁(14、16),所述缸壁(14、16)在径向方向上限定环形的压力室(18),可操作地连接到离合器的环形活塞(20)可移动地接收在其中,其中,所述缸壁(14、16)在其背离压缩室(18)的周边侧设置有至少一个加强环(44、46),其中,所述加强环(46)附接到外缸壁(16)的外侧,并且在其轴向范围内分成两个邻接的部分区域(46u、46f),其中第一部分区域(46u)在外侧由来自缸壳体(12)的塑料包围,第二部分区域(46f)在外侧没有来自缸壳体(12)的塑料。本发明还涉及一种制造用于这种中央致动器(10)的缸壳体(12)的方法。(The invention relates to a central actuator (10) for hydraulic or pneumatic clutch actuation, having a cylinder housing (12), the cylinder housing (12) has at least one cylinder wall (14, 16) made of plastic, the cylinder wall (14, 16) delimiting an annular pressure chamber (18) in the radial direction, an annular piston (20) operatively connected to the clutch is movably received therein, wherein the cylinder wall (14, 16) is provided on its peripheral side facing away from the compression chamber (18) with at least one reinforcement ring (44, 46), wherein the reinforcement ring (46) is attached to the outside of the outer cylinder wall (16) and is divided in its axial extent into two adjoining part-regions (46u, 46f), the first partial region (46u) is surrounded on the outside by plastic from the cylinder housing (12), and the second partial region (46f) is free on the outside of plastic from the cylinder housing (12). The invention also relates to a method for producing a cylinder housing (12) for such a central actuator (10).)

1. Central actuator (10) for hydraulic or pneumatic clutch actuation, having a cylinder housing (12), the cylinder housing (12) having at least one cylinder wall (14, 16) made of plastic, the cylinder wall (14, 16) defining in a radial direction an annular pressure chamber (18), an annular piston (20) operatively connected to a clutch being movably received in the pressure chamber (18), wherein the cylinder wall (14, 16) is provided on its peripheral side facing away from the compression chamber (18) with at least one reinforcement ring (44, 46),

it is characterized in that the preparation method is characterized in that,

the reinforcement ring (46) is attached to the outside of the outer cylinder wall (16) and is divided in its axial extent into two adjoining partial regions (46u, 46f),

the first partial region (46u) is surrounded on the outside by plastic from the cylinder housing (12), and the second partial region (46f) is free on the outside of plastic from the cylinder housing (12).

2. Central actuator (10) according to claim 1, characterized in that the second partial region (46f) of the reinforcement ring (46) is axially longer than the first partial region (46u) of the reinforcement ring (46).

3. The central actuator (10) according to claim 1 or 2, characterized in that the first partial region (46u) is axially offset from a flange portion (26) of the cylinder housing (12) connecting the outer cylinder wall (16) to the inner cylinder wall (14).

4. Central actuator (10) according to claim 1 or 2, characterized in that the first partial region (46u) is surrounded on the outside by a flange portion (26) of the cylinder housing (12) made of plastic, which flange portion (26) connects the outer cylinder wall (16) to the inner cylinder wall (14).

5. Central actuator (10) according to any of the preceding claims, characterized in that the reinforcement ring (46) has a surface without grooves and/or protrusions on the inner side facing the outer cylinder wall (16).

6. Central actuator (10) according to the preamble of claim 1, characterized in that the reinforcement ring (44) is attached to the inner side of the inner cylinder wall (14) and in that

The reinforcement ring (44) is free of plastic from the cylinder housing (12) over its entire axial extent.

7. Central actuator (10) according to any of claims 1 to 5, characterized in that in addition to a reinforcement ring (46) attached to the outside of the outer cylinder wall (16), a further reinforcement ring (44) is attached to the inside of the inner cylinder wall (14), wherein the further reinforcement ring (44) is free of plastic from the cylinder housing (12) over its entire axial extent.

8. A central actuator (10) according to claim 6 or 7, characterized in that the further reinforcement ring (44) is axially offset from a flange portion (26) of the cylinder housing (12) connecting the outer cylinder wall (16) to the inner cylinder wall (14).

9. A central actuator (10) according to any of claims 6 to 8, characterized in that the inner side surface of the reinforcement ring (44) terminates on at least one axial edge radially flush with the inner side of the inner cylinder wall (14).

10. Method for manufacturing a cylinder housing (12) for a central actuator (10) according to any of the preceding claims, characterized in that it comprises the following process steps:

-positioning the reinforcement ring (44, 46) over a partial region of the injection mold for the cylinder housing (12) that remains free of plastic,

-manufacturing the cylinder housing (12) in the injection mould by plastic injection moulding, wherein the reinforcement ring (44, 46) is only partially coated with plastic.

Technical Field

The present invention relates to a central actuator for hydraulic or pneumatic clutch actuation according to the preamble of claim 1. The invention relates in particular to a hydraulic clutch-actuated central actuator for a friction clutch of a motor vehicle, as is widely used in the motor vehicle industry. In this case, the central actuator may be configured as a central release mechanism or a central engagement mechanism or may also be configured as a double central engagement mechanism.

Background

Conventional hydraulic clutch actuation for motor vehicles has a master cylinder attached to a compensation tank filled with hydraulic fluid, which can be operated, for example, by a clutch pedal. The master cylinder is hydraulically connected to the slave cylinder by a pressure line, so that the pressure generated in the master cylinder by depressing the clutch pedal can be transmitted to the slave cylinder by a fluid column in the pressure line. As a result, the release bearing of the friction clutch is acted upon by the actuating force from the slave cylinder in order to disconnect the clutch pressure plate from the clutch carrier plate and thus the engine from the motor vehicle gearbox by means of the release mechanism.

In order to ensure consistent operation of the friction clutch and as little space requirement as possible for the slave cylinder, it has been known in the art for some time to configure the slave cylinder as an annular cylinder which is arranged around the clutch or the gear shaft and is preferably fastened on the gearbox. A ring-shaped piston is movably arranged in an axial direction of the clutch or gear shaft in a ring-shaped cylinder, which is operatively connected to a release bearing of the friction clutch. During the hydraulic exposure of the annular cylinder through the pressure line, the annular piston acts on the release lever or on the fingers of the diaphragm spring of the friction clutch through the release bearing in order to release it. Such slave cylinders are also referred to as central release mechanisms (CSC) because of their concentric arrangement relative to the clutch or gear shaft. In the case of a central release mechanism, the annular piston of the annular slave cylinder acts on the respective engagement member of the friction clutch during hydraulic exposure through the engagement bearing in order to engage said friction clutch.

For cost and weight reasons, modern central actuators have a cylinder housing which is predominantly made of plastic and has at least one outer cylinder wall which delimits radially outwards an annular pressure chamber in which an annular piston which is operatively connected to the clutch is movably received. If necessary, the cylinder housing made of plastic also has an inner cylinder wall which delimits the pressure chamber radially inwards and guides the annular piston; otherwise, a guide sleeve, mainly made of steel plate, is concentrically arranged within the cylinder wall and fastened to the cylinder housing in order to delimit the pressure chamber radially inwards and guide the annular piston. The cylinder housing also has a pressure connection opening into the pressure chamber, through which the pressure chamber can be selectively exposed to a pressure medium in order to release the clutch.

The method of choice for cost-effective production of such cylinder housings in large unit numbers is plastic injection molding. In order to be able to reliably withstand the high loads occurring in the region of the cylinder wall during exposure to the pressure of the pressure chamber and to avoid leakage, it is known in the art to reinforce cylinder walls made of plastic using reinforcing elements.

Thus, DE19951414a1 (see in particular fig. 2 and the associated description in column 5, lines 59 to 67) discloses a cylinder housing of a central release mechanism made of injection molded plastic, wherein for reinforcement of the cylinder housing its outer cylinder wall is provided with a reinforcement (reference numeral 21) for preventing radial widening of the outer cylinder wall during operation of the central release mechanism, i.e. during exposure of the pressure chamber to pressure. In particular, it is proposed in this prior art that a sheet metal sleeve, which is produced without cutting, should be made as a reinforcement, which can be fixed to the side surface of the outer cylinder wall by pressing or shrink fitting. However, the cylinder wall area made of plastic that needs to be reinforced is also susceptible to mechanical stress from the outside by pressing or shrink-fitting, which means that such reinforcement does not seem suitable for avoiding the above-mentioned risk of leakage.

Furthermore, WO90/04116A1 (FIGS. 2, 4, 5 and 10: reference numeral 56), DE10323570A1 (FIG. 3: reference numeral 19) or DE102008006202A1 (FIGS. 1 and 3: reference numeral 17) disclose, for example, a cylinder housing for a central release mechanism made of injection-molded plastic, wherein a possible sleeve-shaped reinforcement is also covered during the injection molding process, in particular in the region of the cylinder wall. On the one hand, however, this complicates the injection mold and the actual injection molding process, since only the reinforcement needs to be inserted into the injection mold, which has a more complex design with respect to the pouring channel guide and the venting channel, and needs to be held there in a properly oriented manner. Possible support elements for this purpose lead to corresponding holes in the plastic during injection molding. On the other hand, due to the heat storage capacity of the metal reinforcement, the plastic in the injection mold may cool and harden less quickly, which leads to an undesirably long residence time of the injection-molded workpiece in the injection mold in mass production.

DE202011109244U1 discloses a central actuator according to the preamble of claim 1. In this case, after the injection molding of the cylinder housing, the reinforcing sleeve is pulled onto the cylinder wall and fastened there by a snap connection. To this end, the reinforcing sleeve at its front end reforms inwardly a conical locking portion which forms a snap connection with a rib formed on the outer periphery of the cylinder wall. When the reinforcing sleeve is slid onto the cylinder wall, the locking portion is locked with the rib formed on the cylinder wall.

Disclosure of Invention

The problem addressed by the present invention is to propose an alternative central actuator for a central actuator of the above-mentioned type for hydraulic or pneumatic clutch actuation, which actuator can be manufactured as easily and cost-effectively as possible and can reliably resist the hydraulic or pneumatic forces generated during operation by means of a firmly fastened stiffening ring.

According to the invention, this problem is solved by a central actuator according to claim 1. Advantageous embodiments and suitable developments of the invention emerge from the dependent claims, the description or the figures, wherein the features described or shown here can represent the object of the invention, individually or in any combination with one another, unless the context clearly implies otherwise.

In the case of a central actuator for hydraulic or pneumatic clutch actuation, which comprises a cylinder housing with at least one cylinder wall made of plastic material, which delimits an annular pressure chamber outwards or inwards in the radial direction, in which pressure chamber an annular piston operatively connected to the clutch is received in an axially displaceable manner, and in which at least one cylinder wall is provided on its peripheral side facing away from the compression chamber with at least one reinforcement ring, it is provided according to the solution of the invention that the reinforcement ring bears against the outside of the outer cylinder wall and that the reinforcement ring is divided in the axial direction into two adjoining part regions, wherein the first of these two part regions is covered on the outside with plastic from the cylinder housing, while the other of these two part regions is free from plastic from the cylinder housing.

In other words, this therefore means that the reinforcement ring is covered on the outside with the plastic of the cylinder housing over a partial region of its axial extent, while the remaining region of its axial extent is free of the plastic of the cylinder housing on the outside.

The only partial covering of the reinforcement ring means that a secure retention on the cylinder wall in the axial direction is achieved without having to provide openings, recesses or protrusions in or on the reinforcement ring for this purpose, which facilitates the use of a simpler and therefore more cost-effective reinforcement ring. It is also not necessary to form specially form-fitting fastening means on the cylinder wall for axially retaining the reinforcement ring, which simplifies the construction.

At the same time, however, the freely accessible partial region of the outer surface also facilitates a simple positioning of the reinforcement ring in the injection mold, as a result of which the production thereof is simplified and the production costs are correspondingly reduced. In the case of a central actuator configured according to the invention, it is therefore possible to avoid the disadvantages of the prior art described above, which occur during the complete covering of the reinforcing element with plastic, due to the relative complexity involved in the fixing of the precise positioning in the injection mold.

Furthermore, in the case of a central actuator formed according to the invention, the reinforcement ring is neither completely pressed nor shrink-fitted onto the outer cylinder wall, so that the disadvantages associated with the prior art, which in this respect indicate additional stresses of the reinforced plastic structure in the case of a central actuator according to the invention, do not occur. The risk associated with possible deformation of the cylinder housing made of plastic is thereby avoided.

A further advantage is that, due to the covering with the plastic part, there is less dependence on possible dimensional tolerances and the reinforcement ring remains firmly in place even at higher temperatures. In particular, the only partial external covering of the reinforcement ring leads to a further reinforcing effect and dimensional stability in the partial region enclosed by the plastic.

The plastic applied to the outside of the reinforcement ring also prevents the formation of sharp edges in the cylinder wall, which would otherwise occur at the contact points between the reinforcement ring and the adjacent regions of the cylinder wall. Furthermore, the plastic applied to the outside of the reinforcement ring can at the same time still be used for further functions, such as to form a ramp for the pretensioning spring of the central actuator or to form a connection for other hydraulic components.

The reinforcement ring is preferably made of an annular metal plate, which means that a cost-effective production can be achieved by a simple construction. For example, the reinforcement ring may be made of aluminum or spring steel.

The axial length of the reinforcement ring can be freely adjusted according to the respective application. According to a preferred embodiment, the free second partial region of the reinforcement ring on the outside in the axial direction has a greater length than the first partial region of the reinforcement ring covered with plastic on the outside.

According to a first embodiment of the central actuator according to the invention, an axial space is formed between the first partial region surrounded by the outer plastic and the flange portion of the cylinder housing connecting the outer cylinder wall to the inner cylinder wall. The reinforcement ring can then be located in particular in the axial central region of the outer cylinder wall, which region must be rigidly supported with respect to the load of the pressure medium and thus avoids detrimental structural changes of the plastic. The exact axial positioning of the reinforcement ring may also be adapted to the respective application.

According to an alternative embodiment of the invention, the first partial region of the reinforcement ring can be surrounded on the outside by a flange portion of the cylinder housing made of plastic, which connects the outer cylinder wall to the inner cylinder wall. In this case, the reinforcement ring then supports the region of the outer cylinder wall adjacent to the bottom of the annular pressure chamber, without an axial space being present between the reinforcement ring and the flange portion of the cylinder housing.

It is particularly advantageous if the reinforcement ring has a flat surface on the inner side facing the outer cylinder wall, i.e. it has no grooves and no protrusions. However, sufficient axial retention of the reinforcing ring can be achieved by the outer partial plastic cover.

The subject matter of the invention also includes a central actuator of the type described above, in which the reinforcement ring is located inside an inner cylinder wall made of plastic, which wall forms a guide sleeve for the annular piston and inwardly delimits an annular pressure chamber, wherein the reinforcement ring is free of plastic from the cylinder housing on the inside over its entire axial longitudinal extent.

Thus, the inner reinforcement ring, unlike the completely covered reinforcement element, can also be easily supported and positioned in the injection mold from the inside, wherein the inner reinforcement ring is also only partially covered with plastic, i.e. on the outside and the front side. Here, too, production is therefore correspondingly simplified and made more cost-effective. In this case, a firm axial retention is achieved by the front end of the reinforcing ring axially abutting against the adjacent cheek (chek) of the plastic covering.

The invention also relates to a central actuator of the above-mentioned type, which comprises at least one inner reinforcement ring and an outer reinforcement ring of the above-mentioned type, respectively. In this case, the reinforcement ring attached to the outside of the outer cylinder wall is therefore surrounded by plastic from the cylinder housing only over a partial region of its axial extent, while its remaining axial residual region is likewise free of plastic from the cylinder housing on the outside, since the at least one reinforcement ring adjoining the inner cylinder wall on the inside is free of plastic from the cylinder housing on the inside thereof. In this case, both the outer reinforcement ring and the inner reinforcement ring are only partially covered with plastic, which leads to the aforementioned advantages, respectively.

It is particularly advantageous that the further reinforcement ring is attached to the inner cylinder wall on the inside so as to be axially offset from a flange portion of the cylinder housing connecting the outer cylinder wall to the inner cylinder wall. In this case, the exact axial positioning of the inner reinforcement ring may also be adapted to the respective application.

According to a particularly preferred embodiment of the invention, an inner surface of the inner reinforcement ring is provided, which is preferably likewise smooth, i.e. without grooves and/or protrusions, ending in a step-free manner with the inner side of the inner cylinder wall on at least one front end of the reinforcement ring in the radial direction. This means that at least one, but preferably both, axial edges of the reinforcement ring merge in a flush manner with the inner side of the inner cylinder wall, so that in this case there is no step extending over the inner circumference of the inner cylinder wall.

The invention also relates to a method for producing a cylinder housing for a central actuator of the aforementioned type. The manufacturing method at least comprises the following process steps:

the reinforcement ring is positioned above a partial region of the injection mold for the cylinder housing which remains free of plastic,

the cylinder housing is produced in the injection mold by plastic injection molding, wherein the reinforcement ring is only partially covered with plastic.

Drawings

Further advantages and features of the invention result from the following description of exemplary embodiments which are shown in the drawing. In these figures:

figure 1 shows a longitudinal cross-section of a conventional central release mechanism,

figure 2 shows a longitudinal cross-sectional view of a first embodiment of a cylinder housing constructed in accordance with the present invention,

figure 3 shows a longitudinal section through a variant of the first embodiment of the cylinder housing according to the invention,

FIG. 4 shows a longitudinal cross-sectional view of a second embodiment of a cylinder housing constructed in accordance with the present invention, an

Figure 5 sets forth a longitudinal cross-sectional view of a third embodiment of a cylinder housing constructed in accordance with the present invention.

Detailed Description

Fig. 1 shows a hydraulic clutch actuated central release mechanism 10 for a dry friction clutch in a non-installed state in a basic position. The central release mechanism 10 has an injection-molded cylinder housing 12 made of plastic, for example GF-filled polyphthalamide, which has two concentrically arranged cylinder walls, an inner cylinder wall 14 and an outer cylinder wall 16, which delimit an annular pressure chamber 18. An annular piston 20, which can be operatively connected to a clutch (not shown), is received in the pressure chamber 18 movably in the axial direction, and is exposed to a pressure medium, optionally via a pressure connection fitting 22 of the cylinder housing 12, in order to disengage the friction clutch by movement of the annular piston 20. To this end, the pressure connection fitting 22 is connected to the pressure chamber 18 via a channel 24 formed in the cylinder housing 12, so that pressure medium, i.e. hydraulic fluid, can be supplied to the pressure chamber 18 via the channel 24.

The cylinder walls 14 and 16, which are arranged concentrically with each other, are connected to each other at the end shown on the right side in fig. 1 by a flange portion 26. The flange portion 26 is provided on the outer periphery with a plurality of angularly spaced fastening eyelets (not shown) which are used in a manner known per se for motor vehicles to fasten the central release mechanism 10 to a gearbox wall or gearbox cover (not shown) by means of screws which, for example, pass through the fastening eyelets and pull the central release mechanism 10 with its front end 28 of the cylinder housing 12 against the gearbox wall or gearbox cover. The cylinder housing 12 with the pressure connection fitting 22 adjoining the flange portion 26, its cylinder walls 14 and 16 and the flange portion 26 connecting them and supporting the fastening eye is preferably injection molded in one piece from plastic.

The outer cylinder wall 16 is surrounded by a pretensioning spring 30, which spring 30 is shown in the exemplary embodiment by a conically expanding helical compression spring which rests on the flange section 26 of the cylinder housing 12 at its right end in fig. 1 by means of an annular sheet metal part 32 and which exerts a defined pretensioning force on a release bearing 36, known per se, at its left side in fig. 1 by means of a deep-drawn spring plate 34 made of sheet metal. The release bearing 36 is fastened to the left end of the annular piston 20 shown in fig. 1 in a suitable manner, so that when the annular pressure chamber 18 is exposed to pressure in the axial direction (i.e. horizontally in fig. 1), the release bearing 36 can be moved in order to release or engage the dry friction clutch in a manner known per se.

At the right end of the annular piston 20 in fig. 1 (which in the basic position shown in the axial direction overlaps the outer cylinder wall 16), a dynamic seal 38 in the form of an elastomer sealing sleeve is attached in a form-fitting manner. The sealing sleeve, which is shown in a non-deformed state (for the sake of simplicity of illustration in this case), is close to the inner cylinder wall 14 of the cylinder housing 12 and also close to the outer cylinder wall 16 of the cylinder housing 12, in order to seal the pressure chamber 18 to the left with respect to fig. 1.

The outer cylinder wall 16 is provided with a reinforcing sleeve 40 on its outer circumference, the reinforcing sleeve 40 being fastened to the outer cylinder wall 16 by a snap connection 42 when the components belonging to the central release mechanism 10 are in the position shown in fig. 1, the snap connection 42 being provided at the end of the reinforcing sleeve 40 remote from the pressure connection fitting 22. The reinforcing sleeve 40 is arranged substantially in the central region of the outer cylinder wall 16, which must be supported against the pressure in the pressure chamber 18 to avoid structural changes that destroy the plastic.

In the case of the exemplary embodiment according to the invention shown in fig. 2 to 5, the inner reinforcement ring 44 and/or the outer reinforcement ring 46, respectively, are only partially covered with plastic of the cylinder housing 12. This covering means that no additional means for axially retaining the reinforcement rings 44 and 46, such as a snap connection 42 of the type shown in fig. 1, are required.

In the case of the embodiment shown in FIG. 2, the outer reinforcement ring 46 rests on an axially central region outside the outer cylinder wall 16. It is divided into two axially adjacent part- areas 46f and 46u which together cover the entire axial extent of the reinforcement ring 46. The first subregion 46u is covered on its outside by a collar 48 made of the plastic material of the cylinder housing 12. The plastic collar 48 covers the first partial region 46u over its entire extent. It is much thinner in the radial direction than the thickness of the reinforcement ring 46, wherein the thickness of the reinforcement ring 46 is in turn substantially smaller than the thickness of the thus reinforced portion of the outer cylinder wall 16. The second partial region 46f of the reinforcement ring 46, which is directly axially attached to the first partial region 46u, is not covered on its outside and therefore does not have the plastic of the cylinder housing 12.

Since the reinforcement ring 46 in this case rests on the axially central region of the outer cylinder wall 16, it is located at an axial distance 50 from the flange portion 26 of the cylinder housing 12, which flange portion 26 connects the outer cylinder wall 16 to the inner cylinder wall 14. Outside this space 50, the outer cylinder wall 16 has the same outer diameter as the collar 48, which means that there is no seam or even a step on the outside in this case.

In contrast, in the case of the embodiment shown in fig. 3, there is no such axial space. In this case, the outer reinforcement ring 46 bears axially against the flange portion 26 of the cylinder housing 12, so that its first partial region 46u is surrounded on the outside by the plastic material of the flange portion 26.

In both embodiments (fig. 2 and 3), the reinforcing ring 46 is configured on its inner side as well as on its outer side as a flat cylinder face, in each case without grooves and also without radially projecting regions.

In the case of the embodiment shown in fig. 4, the inner reinforcement ring 44 is located in the axially central region of the inside of the inner cylinder wall 14 to stabilize the cylinder wall. In this case, the reinforcement ring 44 is in contact with the plastic material of the cylinder housing 12 only on its outer side and its two front ends, while its inner surface is completely free of the plastic of the cylinder housing 12.

The embodiment depicted in fig. 5 corresponds to a combination of the two embodiments shown in fig. 2 and 4. In this case, the inner reinforcement ring 44 is attached to the inner cylinder wall 14 and the outer reinforcement ring 46 is also attached to the outer cylinder wall 16. Here, too, the outer reinforcing ring 46 is surrounded only in a partial region 46u of its axial extent by a thin plastic collar 48 from the cylinder housing, while the remaining axial partial region 46f thereof is free of plastic of the cylinder housing 12 on the outside.

In a corresponding manner, the inner reinforcement ring 44 adjoining the inner cylinder wall 14 does not contact the plastic of the cylinder housing 12 on the inside. Thus, both the inner reinforcement ring 44 and the outer reinforcement ring 46 are only partially covered with plastic from the cylinder housing 12.

The two reinforcing rings 44 and 46 are designed to be equally wide in the axial direction. They are also located at the same height in the axial direction, in other words in the same axial section of the annular pressure chamber 18, which is therefore stable both inwards and outwards in this case.