WO2013072017A1

WO2013072017A1 - Piston for a door closing device

Info

Publication number: WO2013072017A1
Application number: PCT/EP2012/004558
Authority: WO
Inventors: Jackson Leong; Oliver Riess
Original assignee: Dorma Gmbh + Co. Kg
Priority date: 2011-11-14
Filing date: 2012-10-31
Publication date: 2013-05-23
Also published as: EP2780525A1; TW201329332A; DE102011055317A1

Abstract

The invention relates to a piston (10) for a door closing device, comprising a cavity (20) surrounded by an enclosure (30), and having at least one opening (32), wherein a pressure relief valve (40) is movably arranged between at least two positions inside the opening (32), characterized in that the valve (40) is provided with valve means (42) and a surrounding housing (44) having sealing means (46) for sealing the opening (32) in a first position of the valve (40). A holding device (50) is arranged on the enclosure (30) for fixing the second position of the valve (40).

Description

The present invention relates to a piston for a door closing device and a pressure relief valve and a method for damping a piston of a door closing device.

Door closing devices and pistons for door closing devices are known in the art. Such pistons usually have an inner cavity which is surrounded by an enclosure. Such internal cavities are used for damping during movement of the piston in a first direction by receiving oil from the outside. When the piston is moved in a second direction, the oil is squeezed out of the inner cavity, thus further damping the movement of the piston. Known pistons use pressure relief valves, which are arranged within an opening and movable between at least two positions. One position of such a relief valve is used for the flow of oil into the interior of the enclosure, while the other position is used for the flow of oil in the opposite direction. Accordingly, the valve is movable between two positions, wherein the first position of the pressure relief valve is opened against a spring force. In the second position, the spring force is switched off so that the oil flow can pass laterally through the valve body.

A disadvantage of known pistons for door closing devices is that they require very precise tolerances during production. Known pistons have a pressure relief valve which is surrounded by a bushing. This bushing must be fixed in the opening of the housing of the piston by press fit. The press fit itself requires very tight tolerances. during the manufacture of the enclosure of the piston. In addition, the press fit due to high temperatures in the other steps of the manufacturing process is changed with high probability. In particular, the geometric dimensions of the enclosure and the geometric dimensions of the bushing change due to different thermal conditions. Thus, there is the risk that the press fit is lost and the bushing does not have the necessary pressing force to be stored securely inside the opening of the housing. Moreover, the use of a bushing and a relief valve increases the complexity of the overall system and increases the number of parts, thereby also increasing the cost of manufacturing such a piston.

It is an object of the following invention to at least partially overcome the disadvantages described above. In particular, it is an object of the present invention to provide a piston for a door closing device, a pressure relief valve and a method for damping a piston of a door closing device, wherein the tolerances in the manufacture of each of the components may be less selected.

The above object is achieved by a piston having the features of independent claim 1, a pressure relief valve having the features of independent claim 12 and a method for damping a piston of a door closing device according to the features of independent claim 13. Further features and details of the invention will become apparent the dependent claims, the description and the drawings. Features and details described with respect to the piston of a door closing device also apply with reference to a method according to the invention and with reference to a pressure relief valve according to the invention. An inventive piston for a door closing device has a cavity and a surrounding housing with at least one opening, wherein a pressure relief valve is disposed within the opening movable between at least two positions. The two positions are defined as a first position and a second position. As a result, in the first position, the pressure relief valve is used to open against a sealing force of the pressure relief valve. In the second position, the pressure relief valve opens a bypass, for example, a surrounding cavity which surrounds the body of the valve to allow fluid, especially oil, to flow along the body of the pressure relief valve. A piston according to the invention is characterized in that the valve valve means and the surrounding housing have sealing means for sealing the opening of the first position of the valve. Further, a holding device is arranged on the housing, that a second position of the valve is defined. By using the holding device can be dispensed with a socket for the arrangement of the pressure relief valve within the opening. Such sockets are no longer necessary in the use of the present invention. It is also possible that the geometric dimensions are kept in easily achievable, low tolerance ranges, since no interference fit within a piston according to the invention must be provided more. The pressure relief valve itself has valve means which are well known. For example, such valve means comprise a spring element and a valve element, which are pressed by the spring element in the valve seat. In order to open the valve means, the force of the spring element must be applied by the fluid pressure and thus the valve means must be pushed into a position in which it no longer opposes the flow of oil.

A piston according to the invention can be manufactured in a cost effective and simpler way. Due to the fact that no additional and complex components, such as a socket, and also no interference fit can be used, the valve can be inserted into the opening by hand and without any temperature differences. Furthermore, an influence on the functionality of the pressure relief valve can be avoided in the subsequent production process, in particular if thermal differences arise.

The holding device according to the present invention defines the second position, which is in particular spaced from the first position. The two positions thus define a movement path along which the entire overpressure valve can be moved. Further, the valve has sealing means which are held in place, for example, by the head of the valve. In the movement between the two positions, the head of the valve and the sealing means may act as contact surfaces which contact the holding device and / or the inner wall of the opening, so that two end positions for the path of movement of the valve are defined.

It may be advantageous if, in the case of a piston according to the invention, this is designed such that the housing has guide means for guiding the movement of the valve between the at least two positions. Such guide means are used to optimize movement between the at least two positions. In particular, the guide means are, for example, enlarged bands, such as surfaces, disposed in close proximity to the surrounding inner wall of the opening. Undesirable movement of the piston is thus prevented by the guide means in general. Without the guide means, the repositioning in the sealing position, ie the movement from the second position to the first position, would be possible only by chance and not in a predictable way. By defining the geometric dimensions of the guide means, the repositioning movement into the sealing Position predefined and thus the multiple execution of the movement between the two positions with full functionality possible.

Further, it may be advantageous if the guide means of a piston according to the invention have at least one surface of the housing with a diameter which is larger than the adjacent surfaces of the housing in the vicinity of the surface of the opening. For a cost-effective and easy way for the execution of the geometric dimensions of the guide means is given. Such surface areas are generally and in particular parallel to the surrounding surfaces of the opening, that is, to portions of the inner wall of the opening. Thus, by simply changing the diameter of the body of the valve, the guide means can be formed.

The piston according to the present invention can be developed such that the length of the guide means is more than 1/15 of the length of the valve in the axial direction. For example, the guide means may have a geometrical dimension of mm in the axial direction. Further, the valve itself may have a length between about 10mm and about 15mm. Thus, the length of the guide means has a minimum length, so that the guide means can be designed with high stability and high safety in terms of functionality.

It is also possible that the guide means is arranged in a piston according to the invention in the vicinity of a fastening pin of the valve means and / or spaced from the sealing means. A mounting pin of the valve means is used in the interior of the valve to position the valve means within the valve. The mounting pin is usually designed with a geometrical dimension which is longer than the diameter of the valve. Thus, the mounting pin is visible from outside the valve. The adjacent positioning of the guide Means to the mounting pin leads to a very compact configuration of the entire valve. The compactness of the valve results in the ability to reduce the diameter of the entire piston and thus further offers the possibility of reducing the geometric dimensions of the entire door closing device.

It is also possible that the guide means of a piston according to the invention spaced from the sealing means, in particular by a maximum distance, are arranged. The positioning of the maximum distance guide means provides the advantage of maximizing the lever arm between the seal means and the guide means. This also maximizes the force applied to the valve by the guide means to provide guidance for positioning in the first position during the repositioning movement. This leads to greater stability during this return movement of the valve and thus increases the safety of the functionality of a piston according to the invention.

Further, it is possible according to the present invention that the piston is characterized in that the holding device has at least one spring element, in particular a spring clip. The use of a spring element as a holding device reduces the complexity for the manufacturing process. Such a spring element only requires compression and positioning in the desired position. Then, by completing the compression, the fixture is fixed in the final position.

For such an embodiment, it is possible that the holding device is designed to be placed in one or more grooves of the housing. This results in better alignment and easier attachment to place the fixture in the desired position. It is also possible for at least one groove of a piston according to the invention, in particular all grooves, to be arranged in the inner wall of the opening. The positioning of the grooves within the opening leads to the possibility that the outside of the housing can be used as a functional surface or for other functions. The configuration of the groove within the inner wall of the opening further leads to the possibility that the holding device does not collide with other components of the door closing device for which a piston according to the invention is used.

Alternatively, it is possible that according to the present invention, the holding device is designed to be arranged for an arrangement in a curled position in the housing. For example, different flanging plates can be used to serve for the attachment of the holding device. The production of such an embodiment is optimized in this way. In particular, no additional step is necessary for producing the grooves. An additional workstation in the machine can thus be avoided. Another advantage of such an embodiment is the fact that a shoulder can be made in place of a groove by drilling the opening in the enclosure. The shoulder may form a surface against which the fixture is pressed by the flanging plates. In other words, the shoulder and flanging plates form an alternative method of manufacturing a groove. The use of flanging plates is carried out in particular with two or preferably with three flanging plates. The plates are arranged, for example symmetrically and / or star-shaped to a central axis of the pressure relief valve. In this way, a hiring of the holding device can be avoided and / or reduced. Beading of flanging plates can be done manually or with manually operated tools. Of course, the use of machines for the flanging step may be advantageous if the material or the geometric dimensions of the plates require this. The flanging plates may be formed integrally with the housing. However, it is also possible that the crimping plates are manufactured separately and then secured. Such a fastening can be carried out, for example, by press fit and / or welding.

It is also advantageous that according to the present invention, the valve of a piston according to the invention has at least one through hole on both sides of the guide means with respect to the main axis of the valve. This leads to the possibility for a return of oil. In the second position, the valve with the sealant is located outside the seal position. Oil can flow between the through holes on both sides of the guide means and thus flow past the guide means. In addition, oil can flow along a fluid path which flows from the interior of the enclosure of the housing to the outside, below, in particular to the valve means of the valve leads.

It can also be advantageous for the valve of a piston according to the invention and the opening to have rotationally symmetrical structures, the valve having a head section with a larger diameter than in the case of a shaft section of the valve. This head portion is designed to block the movement of the valve in the second direction and thus to define the second position of the valve. Further, the sealing means may be held at the head portion in the predefined position. The rotationally symmetrical design leads to the possibility of a simple production of the valve body and also to reduce the complexity of the production, in particular with regard to the insertion of the valve in the opening.

Another object of the present invention is the provision of a pressure relief valve, comprising valve means and a surrounding housing with sealing means, the valve being adapted for use in a piston according to the present invention. Accordingly, a pressure relief valve according to the invention brings about the same advantages as have been explained in detail with reference to a piston according to the invention.

Another object of the present invention is to provide a method for damping a piston of a door closing device using a piston according to the present invention. Accordingly, such a method brings the same advantages as have been explained in detail with reference to a piston according to the invention.

The present invention will be explained in more detail with reference to the accompanying drawings. The terms "left," "right," "top," and "bottom" refer to an alignment of the drawing figures with normally readable numerals. They show schematically:

FIG. 1 shows a first embodiment of a piston according to the invention,

FIG. 2 shows an embodiment of the overpressure valve for a piston according to the invention in a first position, FIG. 3 shows the overpressure valve according to FIG. 2 in the second position,

FIG. 4 a shows an embodiment of a holding device,

Figure 4b, the embodiment of the holding device according to Figure 4a in the fastened position and FIG. 4c shows the embodiment of the holding device according to FIG. 4a in an alternatively fastened position.

Figure 1 shows a piston 10 according to the present invention. It has a cavity 20 within a housing 30. The housing 30 further has an opening 32 through which oil can flow in a bidirectional manner. In order to create the possibility that the oil can flow through the opening 32, a pressure relief valve 40 is disposed within the opening 32. In order to hold the pressure relief valve 40 in position, a holding device 50 is arranged in a groove of the housing 30.

In Figure 2, the pressure relief valve 40 is shown in detail. It has valve means 42, which are arranged within the body of the valve 40. By a through hole 41 spring elements can be detected, which press the valve body in the sealing position. In addition, a mounting pin 43 is disposed on the valve 40 to hold the spring member and the valve body of the valve means 42 in the predefined position.

The functionality of the pressure relief valve will now be described with reference to FIGS. 2 and 3. During a situation in which the pressure outside the enclosure 30 is greater than inside the cavity 20 within the enclosure 30, the head portion 40a of the housing 44 of the valve 40 is forced to the first position, as shown in FIG. In this first position, sealing means 46, which are arranged in the vicinity of the head portion 40 a, held in the sealing position. Thus, the valve 40 is sealed against the cavity 20 within the housing 30. When oil flow is generated, this is only possible if the pressure of the oil outside of the housing 30 exceeds a certain pressure defined by the valve means 42 of the valve 40. When the pressure exceeds this limit pressure, the valve member of the valve means 42 opens against the spring force and the oil flow can enter the cavity 20. penetrate. It should be noted that the relief valve 40 remains in the position as shown in Fig. 2 as long as the above-described situation prevails. When the direction of the pressure difference is reversed, that is, when the pressure within the enclosure 30 is higher, the valve means 42 are closed and, moreover, the entire valve 40 is moved along the path of travel. This movement is thereby stopped the holding device 50 at the second position. This second position is shown in FIG. As can be seen in Figure 3, here are the sealing means 46 out of contact with the housing 30. Thus, the valve 40 is no longer sealed against the housing 30. In order to ensure that oil can flow out of the cavity 20 to the outside outside the housing 30, through holes 41 are arranged on both sides of guide means 48. In this way, oil can flow past all obstructive elements, in particular the sealing means 46, and leave the cavity 20.

As can also be seen from FIGS. 2 and 3, guide means 48 are provided. These are formed by a wide band, which is arranged in the vicinity of the surface of the inner wall of the opening 32. When the valve 40 is in a second position situation, as shown in Figure 3, and is to be moved back to the first position, the guide means 48 provide the functionality that tilting of the valve 40 can not occur. Accordingly, the guide means 48 assist the repositioning of the valve 40 in the first position, in particular the repositioning of the sealing means 46 in the predefined sealing position.

Figures 4a and 4b show the possibility of an embodiment of the holding device 50. This embodiment has a spring element. This spring element has two legs which can be elastically compressed and moved to a position as shown in Figure 4b. For example, the retainer 50 may be in a groove of the inner wall the opening 32 are positioned. FIG. 4 b shows a view from the left side of FIGS. 2 and 3 and the valve 40 and the valve means 42. The holding device 50 is arranged within the opening 32 and thus defines the second position of the valve 40.

FIG. 4c shows an alternative possibility of positioning or fastening the holding device 50. Three plates 49 are crimped in the direction of the holding device 50. Thus, the holding device 50 is held in position, without additional grooves are required. In order to achieve the attachment of the holding device 50, after drilling the opening 32 an attachment of the plates 49 for beading on the outside of the housing 30 is formed. In a subsequent step, the pressure relief valve 40 is inserted into the opening 32. After the positioning of the pressure relief valve 40, the holding device 50 can be arranged next to the pressure relief valve 40. After the positioning step, the plates 49 are crimped inwardly to reach a position as shown in Figure 4c. The crimping step may be performed manually or using a tool or a machine. This depends on the geometric dimension of the plates 49 and / or their material. The plates 49 may be formed by the material of the housing 30. For example, a milling step may be used to make the plates 49. Of course, the plates 49 can also be made separately and for external crimping. The attachment of the crimping plates 49 may be made, for example, by welding or interference fit due to the geometric relationship between the plates 49 and the housing 30.

It is to be noted that the holding device 50 according to FIG. 4 c is fastened completely between the plates 49 and a shoulder (not shown) within the opening 32. It should also be pointed out that a shoulder can be easily removed by a first drilling step without an NEN additional step could be made, which would be necessary to produce a groove. Of course, an embodiment without such a shoulder is possible. The number of plates 49 for flanging is not limited to three plates 49. However, three or more plates 49 are advantageous, since a tilting movement of the holding device 50 can be avoided in this way. The different plates 49 are arranged, for example, symmetrically and / or star-shaped relative to a central axis of the overpressure valve 40. This orientation leads to a further prevention of tipping of the holding device 50.

The above explanation of the embodiments of the present invention describes these only in the context of examples. Of course, individual features, if technically expedient, can be combined freely with one another without departing from the scope of the present invention.

LIST OF REFERENCE NUMBERS

10 pistons

20 cavity

30 housing

32 opening

40 pressure relief valve 40a head portion 40b shaft portion

41 Through hole

42 valve means

43 fixing pin

44 housing

46 sealant

48 guiding means

49 plate

50 holding device

Claims

claims

A piston (10) for a door closing device, comprising a cavity (20) with a surrounding housing (30) and at least one opening (32), wherein within the opening (32) a pressure relief valve (40) is arranged movable between at least two positions characterized in that the valve (40) includes valve means (42) and a surrounding housing (44) having sealing means (46) for sealing the opening (32) in a first position of the valve (40), a holding device (50) ) is arranged on the housing (30) for fixing the second position of the valve (40).

A piston (10) according to claim 1, characterized in that the housing (44) comprises guide means (48) for guiding the movement of the valve (40) between the at least two positions.

A piston (10) according to claim 2, characterized in that the guide means (48) comprise at least one surface area of the housing (44) having a diameter larger than the adjacent surface areas of the housing (44) and near the surface of the opening (32) is arranged.

Piston (10) according to one of claims 2 to 3, characterized in that the length of the guide means (48) is more than 1/15 of the length of the valve (40) in the axial direction.

Piston (10) according to one of claims 2 to 4, characterized in that the guide means (48) adjacent to a mounting pin (43) of the valve means (42) u / o spaced from the sealing means ^' (46) are arranged.

6. piston (10) according to one of claims 2 to 5, characterized in that the guide means (48), in particular at a maximum distance, spaced from the sealing means (46) are arranged.

7. Piston (10) according to any one of the preceding claims, characterized in that the holding device (50) has at least one spring element, in particular a spring clip.

8. Piston (10) according to claim 7, characterized in that the holding device (50) is designed for an arrangement in one or more grooves in the housing (30).

9. piston (10) according to claim 8, characterized in that at least one groove, in particular all grooves, on an inner wall of the

Opening (32) are arranged.

10. Piston (10) according to claim 7, characterized in that the holding device (50) is designed for an arrangement in a curled position in the housing (30).

11. Piston (10) according to any one of the preceding claims, characterized in that the valve (40) has at least one through hole (41) on both sides of the guide means (48) with respect to the main axis of the valve (40).

12. Piston (10) according to any one of the preceding claims, characterized in that the valve (40) and the opening (32) have a rotationally symmetrical structure, wherein the valve (40) has a head portion (40a) with a larger diameter than a shaft portion (40b) of the valve (40).

A pressure relief valve (40) comprising valve means (42) and a surrounding housing (44) having sealing means (46), said valve (40) being adapted for use in a piston (10) according to any one of claims 1 to 12.

14. A method for damping a piston (10) of a door closing device, using a piston (10) according to any one of claims 1 to 12.