Piston housing unit having a piston guide

Abstract

The invention relates to a piston housing unit (1) comprising: - a piston (3), - a housing (2), wherein the piston (3) is provided in the housing (2) so as to be displaceable along an axis (X) and is connected to a transmission element (5) of the piston housing unit (1), wherein the transmission element (5) is supported by a first bearing (6) and a second bearing (7). The invention also relates to a piston (3), a housing (2), a transmission element (5) and an actuator (10).

Description

[0001] DESCRIPTION

[0002] Piston housing unit with piston guide

[0003] The present disclosure relates to a piston-housing unit, a piston, a housing, a transmission element and a pressure-medium-operated actuator.

[0004] Piston-housing units 20, as shown in Fig. 1, are known. A piston 3 is slidably provided in a housing 2, the piston 3 together with the housing 2 enclosing a cavity 4 whose volume can be adjusted between a maximum and a minimum volume according to the displacement of the piston 3. The piston 3 is connected to a mechanical transmission element 5 that extends through the housing 3. The transmission element 5 is, for example, designed as a piston rod. In the known piston-housing units 20, the piston 3 is supported in the housing 2 by means of a bearing 6 that is in contact with the transmission element 5. A second bearing point is formed by the piston 3, more precisely its side surface, which is in contact with the inner wall of the housing 2.In this area, a sealing section 8 with sealing elements is also formed on the piston 3, through which the cavity 4 is sealed when the sealing elements are in contact with the inner wall of the housing 2.

[0005] A piston-housing unit 20 as shown in Fig. 1 has the disadvantage that transverse forces, which, for example, from a mechanism in operative connection with the transmission element 5 act on the transmission element 5, cannot be completely supported by the bearing 6. Therefore, a transverse force or a resulting moment in the transmission element 5 must be supported by the piston 3 against the inner wall of the housing. This results in the piston 3 being pressed against the inner wall of the housing on one side, so that the piston seals in the sealing section 8 are subjected to uneven stress, which increases their wear at this point. At the same time, the opposite side of the seals in the sealing section 8 is relieved of stress, which can lead to a loss of sealing effect with respect to the cavity 4.Furthermore, the disadvantage may be that the piston 3 in the known piston-housing units 20 should be designed in such a way that, in the event of a displacement within the housing 2, it can slide along the inner wall of the housing and has a self-centering effect in the housing 2.

[0006] It is therefore the task of the following revelation to solve at least one of the problems described above.

[0007] This problem is solved by the subject matter of the independent claims. Advantageous further developments are the subject matter of the dependent claims described below and the accompanying drawings.

[0008] According to a first aspect of the present disclosure, a piston-housing unit is provided, comprising a piston and a housing. The piston is slidably provided within the housing and is connected to a transmission element of the piston-housing unit. The transmission element is supported by a first bearing and a second bearing.

[0009] In this way, the transmission element can be supported at two bearing points. The two bearings can be fixedly arranged relative to the piston or the transmission element, and, for example, be located in the housing of the piston-housing unit.

[0010] This type of bearing allows the piston to be supported by the bearings acting on the transmission element, thus achieving improved guidance and / or support of the piston in the housing.

[0011] The piston-housing unit may have an axis. The piston may be designed to be displaceable along the axis. The housing may extend along the axis. The transmission element may extend along the axis. The piston-housing unit may be designed for use in a vehicle, particularly a commercial vehicle.

[0012] The connection between the transmission element and the piston can be designed to be axial, so that the piston and transmission element are connected to each other in the axial direction. This allows for the transmission of piston force to the transmission element in the axial direction.

[0013] The transmission element and piston can be arranged coaxially to each other and, in particular, coaxially to the axis of the piston housing unit.

[0014] The piston can close off a cavity within the housing, the volume of which can be adjusted according to the piston's displacement. The transmission element represents a mechanical interface between the piston-housing unit and can, for example, be designed as a piston rod.

[0015] The transmission element can transmit a movement or displacement of the piston, or a piston force. In particular, the transmission element can include a coupling section that allows the force or displacement to be transmitted, for example, to a mechanism connected or coupled to the coupling section. In this way, the mechanism can be actuated by the piston-housing unit.

[0016] The piston displacement or piston force can be caused or generated in response to the supply of pressure medium to the cavity or in response to the discharge of pressure medium from the cavity. In this way, pressure medium-based control or actuation of the piston and a coupled mechanism is possible.

[0017] The pressure medium can be gaseous or liquid. In particular, the pressure medium can be compressed air or hydraulic fluid. Thus, the piston-housing unit is especially suitable for problematic or hydraulic applications. The housing in which the piston is guided can be designed, in particular, as a cylinder. In this way, a conventional or well-known housing geometry can be formed in the area where the piston is slidably located, which can be easily manufactured using known processes such as tension forming and / or casting.

[0018] A sealing section can be provided between the piston and the housing. This section can, for example, be formed on a side surface of the piston facing the inner wall, along which the piston is slidable. The sealing section can have one or more sealing elements designed to seal the cavity by interaction with or contact with the inner wall of the housing. The sealing element(s) can be designed as piston seals. The arrangement of the first and second bearings can, in particular, relieve stress on the sealing section and thus on the sealing element(s).

[0019] The first and second bearings can be positioned between the piston and the coupling section of the transmission element. Transverse forces acting on the transmission element, which are transmitted from the mechanism to the transmission element via the coupling section (for example, as a reaction force), can be supported by the two bearings located between the coupling point and the piston. This reduces or completely eliminates the effect of these transverse forces on the piston. As a result of the transverse force acting on the transmission element, the piston is not forced against one side of the housing's inner wall, thus preventing or at least reducing uneven loading of the piston.

[0020] If the piston has a sealing section as described above, the effect of the transverse force acting on the transmission element on this sealing section is eliminated or at least reduced. This prevents or reduces one-sided loading or pressure on the sealing element(s) of the sealing section, thus protecting the sealing element(s). Furthermore, it prevents the side of the piston or sealing section opposite the side against which the piston is pressed against the inner housing wall from being relieved of pressure, thus preventing a reduction in the sealing effect of the sealing section.

[0021] The bearings can be designed to center the piston within the housing. In other words, the piston or the transmission element is guided by the first and second bearings during displacement in such a way that deviation of the piston perpendicular to the direction of displacement is prevented. This can be achieved, for example, by correspondingly low tolerances between the first and second bearings on the one hand, and the transmission element on the other. In this way, the piston maintains its position within the housing during displacement, preventing deviation perpendicular or radial to the direction of displacement. Thus, the piston surface maintains a constant distance from the inner wall of the housing, along which the piston is slidably mounted, during displacement.This allows, in particular, the provision of a piston that does not slide along the inner wall of the housing while it is being moved, but is spaced away from the inner wall of the housing, especially in the radial direction.

[0022] If the piston has a sealing section, the centering effect of the bearings can improve the sealing performance. This is because the reduced or non-existent lateral deviation of the piston during movement allows the sealing element(s) of the sealing section to bear evenly against the inner wall of the housing in the circumferential direction. This ensures that the sealing element(s) are pressed uniformly against the inner wall, thus optimizing the sealing effect. This is primarily due to the fact that the centering effect prevents the piston from contacting the inner wall of the housing on one side only. Consequently, there are no areas in the sealing section where the seal is pressed more tightly against the inner wall than elsewhere. This avoids creating areas of reduced pressure in the sealing section opposite the areas of increased pressure, thus preventing leakage or a reduction in the sealing effect.Furthermore, the uniform positioning of the sealing element(s) reduces the wear of these sealing elements.

[0023] At least one of the bearings can be designed as a plain bearing. A plain bearing is suitable for absorbing comparatively high forces in a radially limited space, while the contact surface of the plain bearing, designed for force absorption, can be adapted to the specific requirements by the axial extension of the plain bearing. A plain bearing can be designed to be maintenance-free, so that no maintenance or replacement of the corresponding plain bearing is necessary over the service life of the piston-housing unit. At least one of the plain bearings can be designed to be lubrication-free, thus eliminating the need for lubrication. This can be achieved, for example, by using suitable bearing materials such as low-friction plastics. Such a plain bearing can be designed to be sleeve-shaped, through which the transmission element extends.The sleeve shape allows for a relatively large contact area between the transmission element and the corresponding sliding bearing, enabling guidance in the direction of displacement and, if necessary, centering as described above.

[0024] The first and second bearings can be spaced apart along the axis. This spacing can be chosen to generate reaction forces that form a force couple, counteracting a moment induced, for example, by forces introduced into the coupling section of the transmission element. In this way, in addition to absorbing lateral forces, the first and second bearings can also generate a reaction moment that counteracts the moment acting on the transmission element. This prevents or at least reduces the transmission of moment to the piston, thus preventing or reducing piston tilting within the housing due to the moment. This allows for improved piston guidance within the housing and a more uniform contact of the sealing element(s), if present.The present disclosure provides a piston-housing unit that enables the guiding and centering of the piston within the housing. In particular, a piston can be provided that is not designed to contact the inner wall of the housing, thus preventing, for example, tilting of the piston within the housing. In other words, the piston can be axially short and, in particular, may not have a running surface on its circumference that could contact the inner wall of the housing. Specifically, the piston can be essentially disk-shaped, meaning that the axial extent of a cylindrical surface of the piston is at most as large as its radial extent. In this way, a piston with reduced mass can be realized, thus reducing the moving mass of the piston-housing unit. Alternatively or additionally, the axially shorter piston results in...Its axially shorter outer surface allows for a shorter axial length of the housing in which the piston is guided and the cavity is formed. This results in a space-saving advantage for the piston-housing unit. A section designed to connect or link the transmission element to the piston can lead to a local deviation of the piston from the disc shape, as this section may, for example, extend axially towards the transmission element to achieve the connection.

[0025] Further aspects of the present disclosure are explained below. If these relate to items described in connection with the preceding description of the piston housing unit, the features of these items already described are to be understood as at least further developments of the items described below.

[0026] According to one aspect of the present disclosure, a piston is provided for a piston-housing unit as described above. The piston can be configured as described above. In particular, it can be connected to a transmission element, such as a piston rod, which is configured to be supported by means of two bearings as described above. The bearings can be part of the piston-housing unit. Alternatively or additionally, the piston is essentially disc-shaped.

[0027] According to one aspect of the present disclosure, a transmission element for a piston-housing unit as described above is provided. The transmission element is designed to be supported by means of at least two bearings of the piston-housing unit.

[0028] According to one aspect of the present disclosure, a housing for a piston-housing unit as described above is provided. The housing has at least two bearings designed to support a transmission element. Alternatively, the housing has at least two bearing seats designed to receive such bearings. The bearings can, in particular, be designed as plain bearings.

[0029] According to one aspect of the present disclosure, an actuator is provided, which may in particular be configured as a pressure-medium-operated actuator. The actuator comprises a mechanism and a piston-housing unit as described above. The mechanism is operatively connected to the piston-housing unit. The operative connection may be established via the transmission element of the piston-housing unit, more precisely via the coupling section of the transmission element, which is operatively connected to the mechanism.

[0030] The actuator may be intended for use in a vehicle, particularly in a commercial vehicle.

[0031] A piston force or displacement can be transmitted to the mechanism via the mechanical linkage, enabling the mechanism to implement its functionality. For example, the actuator can be configured as a clutch actuator. In this case, the mechanism can provide a mechanical connection to a vehicle's clutch. The clutch can be actuated by the mechanism in response to the piston force or displacement applied to the mechanism. In another example, the actuator can be configured as a transmission divider. In this case, the mechanism can provide a mechanical connection to an actuating element within a vehicle's transmission. The actuating element can be actuated by the mechanism in response to the piston force or displacement applied to the mechanism, for example, to perform a gear or gate selection movement.

[0032] Further embodiments of the disclosure are explained below with reference to the accompanying drawings.

[0033] They show:

[0034] Fig. 1 shows an embodiment of a piston housing unit according to the prior art,

[0035] Fig. 2 shows an embodiment of a piston housing unit according to the present disclosure, and

[0036] Fig. 3 shows an actuator according to the present disclosure.

[0037] Fig. 1 shows an embodiment of a piston-housing unit 20 according to the prior art. This was already described above in the explanation of the problem. It should be added here that the piston 3 is designed to come into contact with the inner wall of the housing 2 in order to guide the piston 3 and secure it against tilting. For this purpose, the piston 3 has a minimum axial extension, which is indicated by the two horizontal lines on the sealing section 8 of the piston 3.

[0038] Fig. 2 shows an embodiment of a piston housing unit according to the present disclosure.

[0039] A piston-housing unit 1 is shown, comprising a piston 3 and a housing 2. The piston 3 is slidably mounted along an axis X within the housing 2, and together with the housing 2, it encloses a cavity 4 whose volume can be adjusted between a maximum and a minimum volume depending on the displacement of the piston 3. The piston 3 is connected to a mechanical transmission element 5, which extends through the housing 2 to the right from a piston surface facing away from the cavity 4. The transmission element 5 is, for example, designed as a piston rod.

[0040] In the piston-housing unit 1 shown, the piston 3 is mounted in the housing 2 by means of a first bearing 6 and a second bearing 7, which are in contact with the transmission element 5. Both bearings 6, 7 provide two bearing points for the unit consisting of piston 3 and transmission element 5, so that a further bearing point or a further support for this unit on the piston 3 can be omitted.

[0041] The transmission element 5, whose right free end extends to the right out of the housing 2 in the drawing, can be operatively connected to a mechanism (not shown) to which a piston force or piston displacement can be transmitted via the transmission element 5. The right free end of the transmission element can therefore be designed as a coupling section with which the connection to the mechanism can be established.

[0042] The first bearing 6 and the second bearing 7 are designed here as low-maintenance plain bearings, which are specifically designed to create a comparatively large contact area with the transmission element 5, so that the absorption of transverse forces acting on the transmission element 5 can be carried out over the largest possible area of ​​the bearings 6, 7. The transverse forces can be applied to the piston-housing unit 1, more precisely to the transmission element 5, by a mechanism connected to the coupling section (not shown).

[0043] In the direction of axis X, the first bearing 6 and the second bearing 7 are arranged such that they are positioned between the free end of the transmission element 5 or the coupling section and the piston 3. In this way, the transverse forces introduced via the coupling section can be adequately supported by both bearings 6 and 7, so that they do not act on the piston 3, or only to a minimal extent. This prevents one-sided contact of the piston 3 with the inside of the housing 2. It also prevents one-sided loading of one or more sealing elements located in a sealing section 8 between the piston 3 and the inner wall of the housing. This protects the sealing elements and simultaneously prevents one-sided loading or unloading of the sealing element(s), thus maintaining the sealing effect of the sealing section 8 and ensuring that the cavity 4 is adequately sealed.

[0044] In the illustrated embodiment, the bearings 6, 7 are spaced apart from each other along axis X, the spacing being such that a transverse force applied to the transmission element 5 via the coupling section generates a couple of reaction forces in the bearings 6, 7, which compensates for or at least weakens the moment introduced into the transmission element 5 by the transverse force. In this way, it can be prevented that this moment acts on the piston 3 and that it tilts, for example, about an axis perpendicular to the plane of the drawing.

[0045] Due to the bearings 6, 7, which axially guide the transmission element 5 and thus the piston 3, the piston is centered within the housing 2. This centering allows the piston 3 to be designed without requiring guidance against the inner wall of the housing, so that only the sealing section 8, which seals the cavity 4 against the housing 2, is necessary. An axial extension of the piston 3, for example in the form of a cylindrical surface extending over a section along axis X, is not required, particularly to guide the piston 3 axially against the housing wall and / or to support it against tilting. Instead, the axial extension of the piston 3 can be limited to making it sufficiently robust to withstand the pressure forces acting in the cavity 4. The piston 3 can therefore, for example, be essentially disc-shaped.

[0046] Fig. 3 shows an actuator according to the present disclosure.

[0047] Shown is an actuator 10, which can be configured in particular as a pressure-medium-operated actuator. The actuator has a mechanism 9 and a piston-housing unit 1, as shown, for example, in Fig. 2. The mechanism 9 is operatively connected to the piston-housing unit 1. The operative connection is established via the transmission element 5 of the piston-housing unit 1, more precisely via the coupling section of the transmission element 5, which is operatively connected to the mechanism 9.

[0048] A piston force or piston displacement can be transmitted to the mechanism 9 via the functional connection, enabling the implementation of a function provided by the mechanism 9. For example, the actuator 10 is configured as a clutch actuator. In this case, the mechanism 9 can represent a mechanical connection to a vehicle's clutch. The clutch can be actuated by the mechanism 9 in response to the piston force or piston displacement applied to the mechanism 9 via the functional connection or the transmission element 5. According to another example, the actuator 10 is configured as a transmission divider. In this case, the mechanism 9 can represent a mechanical connection to an actuating element in a vehicle's transmission.The actuating element can be actuated by the mechanism 9 in response to the piston force or piston displacement applied to the mechanism 9 and, for example, perform a gear or lane selection movement.

[0049] REFERENCE MARK LIST

[0050] 1 piston housing unit

[0051] 2 housings 3 pistons

[0052] 4 cavities

[0053] 5 transmission element

[0054] 6 bearings

[0055] 7 bearings 8 sealing section

[0056] 9 mechanism

[0057] 10 Actuator

[0058] 20 piston housing unit

[0059] X-axis

Claims

PATENT CLAIMS 1. Piston housing unit (1) comprising: - a piston (3), - a housing (2) wherein the piston (3) is provided to be displaceable in the housing (2) along an axis (X) and is connected to a transmission element (5) of the piston-housing unit (1) wherein the transmission element (5) is supported by a first bearing (6) and a second bearing (7).

2. Piston housing unit (1) according to one of the preceding claims, wherein the piston (3) closes off a cavity (4) in the housing (2), the volume of which can be adjusted according to the displacement of the piston (3).

3. Piston-housing unit (1) according to one of the preceding claims, wherein a sealing section (8) is formed between piston (3) and housing (2).

4. Piston housing unit (1) according to one of the preceding claims, wherein the first bearing (6) and the second bearing (7) are arranged between the piston (3) and a coupling section of the transmission element (5) for a mechanism (9).

5. Piston housing unit (1) according to one of the preceding claims, wherein the bearings (6, 7) are designed to center the piston.

6. Piston housing unit (1 ) according to one of the preceding claims, wherein at least one of the bearings (6, 7) is designed as a sliding bearing.

7. Piston housing unit (1) according to one of the preceding claims, wherein the first bearing (6) and the second bearing (7) are spaced apart from each other along the axis (X).

8. Piston (3) for a piston housing unit (1 ) according to one of claims 1 to 7, wherein the piston (3) has a transmission element (5) designed to be supported by at least two bearings (6, 7) of the piston housing unit (1 ), and / or wherein the piston (3) is essentially disc-shaped.

9. Transmission element (5) for a piston housing unit (1) according to any one of claims 1 to 7, wherein the transmission element (5) is configured to be supported by means of at least two bearings (6, 7) of the piston housing unit (1).

10. Housing (2) for a piston housing unit (1) according to any one of claims 1 to 7, wherein the housing (2) has at least two bearings (6, 7) configured to support a transmission element (5), or wherein the housing (2) has at least two bearing seats configured to receive such bearings (6, 7).

11. Actuator (10) comprising - a mechanism (9) and - a piston housing unit (1 ) according to one of claims 1 to 7, wherein the mechanism (9) is operatively connected to the piston housing unit (1 ).

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