Clamping element for central release bearing and central release bearing

Abstract

The invention relates to a clamping element for a central release bearing comprising a base ring and a plurality of teeth projecting from the base ring, wherein a gap is provided between each of the teeth, wherein the teeth have a radially inner and / or radially outer surface at their end regions, wherein the radially inner and / or radially outer surfaces each have a principal extension direction, wherein at least the end regions of the teeth are designed such that the principal extension direction of the inner or outer surface of a tooth has an engagement angle to a circumferential direction of the clamping element.

Description

[0001] The invention relates to a clamping element for a central release mechanism, comprising a base ring and a plurality of teeth projecting from the base ring, wherein a gap is provided between each of the teeth.

[0002] The invention further relates to a central release mechanism for actuating a clutch with a clamping element.

[0003] Furthermore, the invention relates to a method for producing a clamping element.

[0004] Pneumatic central release assemblies have become the standard for clutch actuation in heavy commercial vehicles. A central release assemblies comprise a cylinder and a working piston. A clutch disc or pressure plate, which presses against a clutch disc, is mounted on the working piston. By applying a pressurized fluid, such as air or oil, to the working piston, the working piston can be moved out of the cylinder, thus actuating the clutch.

[0005] To compensate for wear and tolerances, a dead volume is maintained for the working piston. This dead volume also serves to space the working piston from a rear wall when the clutch is new. Due to wear on the clutch, the dead volume for actuating the clutch can decrease over time. To prevent this, it has become known to provide an adjustment mechanism with which the clutch can be readjusted.

[0006] For this purpose, the working piston can be constructed in two parts. When the clutch is actuated, the axial position of the two parts of the working piston relative to each other is fixed, whereas the axial position can be changed during an adjustment process. A clamping disc can be provided to fix the axial position. Particularly in clutches for heavy commercial vehicles, it is challenging to provide a clamping disc that can generate a sufficiently high clamping force.

[0007] An object of the present invention is therefore to provide a clamping element, a central release mechanism and a method for producing a clamping element which provides a high clamping force.

[0008] A further object of the present invention is to provide an alternative clamping element, an alternative central release mechanism and an alternative method for producing a clamping element.

[0009] In one embodiment, the present invention achieves the above-mentioned objects in a clamping element for a central release mechanism comprising a base ring and a plurality of teeth projecting from the base ring, wherein a gap is introduced between each of the teeth, in that the teeth each have a radially inner and / or radially outer surface at their end regions, wherein the radially inner and / or radially outer surfaces each have a main direction of extension, wherein at least the end regions of the teeth are designed such that the main direction of extension of the inner or outer surface of a tooth has a pressure angle to a circumferential direction of the clamping element.

[0010] In one embodiment, the present invention achieves the above-mentioned objects in a central release mechanism for actuating a clutch, comprising a cylinder, a working piston, and a preloading element, wherein the cylinder and the working piston are designed to be axially movable relative to one another and together delimit a variable pressure chamber, wherein the working piston has a pressure piston and an actuating piston, wherein a locking device is arranged which is designed to release or block an axial relative movement between the pressure piston and the actuating piston, wherein the locking device has a clamping element and a stop element, wherein the clamping element is arranged on the actuating piston and is designed to establish a fixed, but detachable, connection with the actuating piston by clamping, wherein the pressure piston is designed to be supported on the clamping element during a disengagement process,wherein the stop element is designed to release a clamping of the clamping element, characterized in that the actuating piston has at least one thread, wherein teeth of the clamping element can be brought into engagement with the at least one thread of the actuating piston, in particular wherein the clamping element is designed according to one of claims 1-7.,

[0011] In one embodiment, the present invention also achieves the above-mentioned objects by a method for producing a clamping element, comprising the steps: - Providing a clamping element comprising a base ring and a plurality of teeth projecting from the base ring, wherein a gap is provided between each of the teeth, - Optionally bending the teeth in the direction of a central axis of the base ring by an angle of attack, - Twisting and / or bevelling at least end regions of the teeth along an axis in which the teeth each protrude from the base ring.

[0012] The terms “radial inner surface” and “radial outer surface” are to be understood in the broadest sense and refer in particular in the description, preferably in the claims, to that surface of the teeth which faces away from the base ring.

[0013] The term "main extension direction of the radially inner and / or outer surfaces" is to be understood in the broadest sense and refers, in particular in the description, preferably in the claims, to the direction in which the surface primarily extends. For example, the main extension direction of a rectangular surface is the direction that extends along the longer edge of the rectangle.

[0014] The pressure angle between the main extension direction of the radially inner or outer surface of the teeth and the circumferential direction of the base ring results in a bevel of the end regions of the teeth on the base ring of the clamping element. This bevel allows the teeth to engage a thread. In other words, the end regions of the teeth are rotated or twisted relative to the rest of the teeth.

[0015] This allows the clamping element to engage with its teeth into a corresponding thread on a working piston of the central release mechanism. The thread increases the clamping force of the clamping element. This ensures better fixation of the two-part working piston during clutch actuation.

[0016] One of the advantages achieved is that the clamping element can engage with a corresponding thread on the central release bearing due to the engagement angle of the teeth. The thread increases the clamping force of the clamping element. Another advantage is that the clamping force can be adjusted by adjusting the thread pitch. Another advantage is that the clamping element requires less space to provide a defined clamping force. Furthermore, the clamping element can be clamped on both sides, thus reducing the load on the clamping element.

[0017] Further features, advantages and further embodiments of the invention are described below or will become apparent thereby.

[0018] According to an advantageous development of the invention, the teeth are twisted at least in the end regions of the teeth. By twisting the teeth, a pressure angle of the teeth can be easily created so that they can engage in a thread. A further advantage is that the teeth can be chamfered without removing material. This improves the strength of the teeth. In particular, it is possible for the teeth to be twisted only in the end regions, but not over the remaining length. This ensures that a stop element contacting the teeth contacts the teeth across their entire width and not just at points, since the teeth are not twisted in the contact region and therefore have a uniform contact surface.

[0019] According to an advantageous development of the invention, the teeth are twisted over at least 70%, preferably at least 80%, in particular at least 90%, of their length. In particular, the teeth can be twisted over their entire length. This simplifies the torsion of the teeth, since when twisting the teeth, care must not be taken to ensure that partial areas of the teeth are not twisted. A further advantage is that the end areas of the teeth are only slightly twisted, since the torsion of the teeth is distributed over a large part of the length of the teeth.

[0020] According to an advantageous development of the invention, the base ring and / or the teeth are made at least partially, in particular entirely, of metal, especially sheet metal. One advantage of this is that manufacturing is simplified. In particular, the base ring can be stamped or deep-drawn together with the teeth. The teeth can then be bent and twisted. A further advantage is that a metal clamping element can enable a high clamping force.

[0021] According to an advantageous development of the invention, the teeth protrude from the base ring at an angle of 5 degrees or more and 50 degrees or less, preferably 10 degrees or more and 40 degrees or less, in particular 20 degrees or more and 30 degrees or less, to the plane of the base ring. In other words, the teeth do not protrude exclusively in the radial direction of the base ring, but also have a directional component in the axial direction of the base ring. Thus, the teeth protrude obliquely from the base ring. As a result, the teeth are pressed radially outward when the clamping element is contacted by a pressing piece. One advantage of this is that the clamping force of the clamping element is increased.

[0022] According to an advantageous development of the invention, the base ring comprises an inner base ring and an outer base ring, with the teeth protruding from both the inner base ring and the outer base ring. The clamping element is thus particularly designed in two parts. The inner base ring has teeth that protrude radially inward, and the outer base ring has teeth that protrude radially outward. One advantage of this is that the clamping element can be clamped on both the radially inner and the radially outer sides, thus increasing the clamping force and reducing the load on the clamping element.

[0023] According to an advantageous development of the invention, the inner base ring is circumferentially rotatable relative to the outer base ring, with the teeth arranged on the inner base ring being twisted in the opposite direction to the teeth arranged on the outer base ring. Due to the rotatability of the inner base ring relative to the outer base ring, the inner and outer base rings can be screwed into corresponding threads independently of one another. Due to the opposing torsion directions of the teeth, the inner base ring and the outer base ring can only rotate in opposite directions in the corresponding threads. This prevents the base rings from unduly dragging along.

[0024] According to an advantageous development of the invention, the adjusting piston has two threads, with the threads being designed in opposite directions. In particular, the adjusting piston has an outer and an inner thread that are designed in opposite directions. Thus, a clamping element with outer and inner teeth can engage both threads. This improves the clamping force. Since the threads are designed in opposite directions, this prevents the inner and outer base rings of the clamping element from dragging each other along in an unacceptable manner.

[0025] According to an advantageous development of the invention, the working piston, the stop element, the clutch, and / or the cylinder are arranged concentrically with one another. One advantage of this is that less installation space is required, since the various components share a common centerline.

[0026] According to an advantageous development of the invention, the stop element has a contact area, wherein the contact area has a profile corresponding to the at least partially flat contact of the, in particular twisted, teeth. With the help of the stop element, the clamping of the clamping element can be released, so that the two parts of the working piston - the pressure piston and the actuating piston - can be displaced axially relative to one another. For this purpose, a contact area of ​​the stop element contacts the clamping element. If the stop element had a purely annular contact area, the contact area would only rest on the teeth of the clamping element at certain points, since the teeth of the clamping element are twisted. To prevent this, the stop element has a profile corresponding to the twisted teeth, so that contact between the stop element and the teeth creates surface contact.An advantage of this is that no point-like stress increases occur in the teeth of the clamping element when they are contacted by the stop element.

[0027] According to an advantageous development of the invention, the teeth are twisted in an end region of the teeth such that the pressure angle of the teeth approximately corresponds to the pitch of the thread. This means, in particular, that the pressure angle and the pitch angle of the thread differ by less than 10%, preferably less than 5%, especially less than 1%. One advantage of this is that the teeth have surface contact at the corresponding thread points, since the teeth and the thread have a corresponding pitch. One advantage of this is that the stresses in the teeth are reduced.

[0028] According to an advantageous development of the invention, a retaining element is arranged between the prestressing element and the clamping element, wherein the retaining element contacts the clamping element at a base ring of the clamping element. The prestressing element, for example a spring, axially loads the clamping element with a retaining force. To ensure a larger contact area between the prestressing element and the clamping element, a retaining element can be arranged between the prestressing element and the clamping element. The retaining element transfers the force of the prestressing element to the clamping element. The retaining element can engage the base ring of the clamping element. Since the base ring has a flat surface, the retaining element can contact the base ring over a large area. One advantage of this is that the tension in the clamping element is reduced.

[0029] According to an advantageous development of the invention, a retaining element is arranged between the pretensioning element and the clamping element, wherein the retaining element contacts the clamping element at the teeth of the clamping element. The retaining element can also contact the clamping element at the teeth. The advantage of this is that the clamping effect is improved because the teeth are clamped between the retaining element and the thread. In this case, it is advantageous if the teeth are only twisted in their end region, but not in the contact area of ​​the retaining element. Then the contact surfaces of all teeth lie in one plane. This prevents the contact surface between the teeth and the retaining element from being point-like. It is also conceivable for the teeth to be twisted over their entire length. In this case, the retaining element can have a profile corresponding to the twisted teeth, so that surface contact is still possible.

[0030] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures with reference to the drawings.

[0031] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0032] Preferred embodiments and embodiments of the present invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components or elements.

[0033] This shows Fig. 1a a clamping element according to an embodiment of the present invention, Fig. 1b shows a section of a clamping element according to an embodiment of the present invention, Fig. 1c shows a section of a clamping element according to an embodiment of the present invention, Fig. 1d a clamping element according to an embodiment of the present invention, Fig. 2 a central release mechanism according to an embodiment of the present invention, Fig. 3 shows a section of a central release mechanism according to an embodiment of the present invention, Fig. 4 shows a section of a central release mechanism according to an embodiment of the present invention, Fig. 5 a clamping element in a central release mechanism according to an embodiment of the present invention, Fig. 6 a stop element according to an embodiment of the present invention, and Fig. 7 steps of a method according to an embodiment of the present invention.

[0034] Fig. 1a shows in schematic form a clamping element according to an embodiment of the present invention.

[0035] The clamping element 101a comprises a base ring 102. A plurality of teeth 103 are arranged on the base ring 102. The teeth 103 are approximately rectangular and protrude radially inward from the base ring 102. The teeth 103 and the base ring 102 can be made of metal, for example, sheet metal. The teeth 103 and the base ring 102 can be manufactured as a single piece, thus forming a single component.

[0036] The teeth 103 do not protrude exclusively in the radial direction of the base ring 102, but at an angle of incidence 104 to the radial direction of the base ring 102. In other words, the teeth 103 have both an axial and a radial component. Furthermore, the teeth 103 are twisted along their longitudinal axis 106. The teeth 103 have an end face 107 having a main extension direction 108. The end face 107 is the face facing away from the base ring 102. The main extension direction 108 corresponds to the direction in which the end face 107 primarily extends. In particular, the main extension direction corresponds to the direction of the longest edge of the end surface 107. Since the end surface 107 is largely rectangular, the main extension direction 108 corresponds to the direction of the longer edge 109 of the rectangle.Since the teeth 103 are twisted, the main extension direction 108 of the end surface 107 is not parallel to the circumferential direction of the base ring 102, but has a pressure angle 105. In other words, the pressure angle 105 corresponds to the torsion angle of the teeth 103. In particular, the teeth 103 are thus beveled with respect to the circumferential direction of the base ring 102.

[0037] Fig. 1b shows in schematic form a section of a clamping element according to an embodiment of the present invention.

[0038] The clamping element 101b according to Fig. 1b essentially corresponds to the clamping element 101a according to Fig. 1a. In contrast to the clamping element 101a according to Fig. 1a, the teeth 103 of the clamping element 101b are arranged according to Fig. 1b, the teeth 103 are not twisted over the entire length, but only in their end regions 110. The end regions 110 of the teeth 103 correspond to those regions of the teeth 103 that face away from the base ring 102. The end regions 110 comprise up to 30%, in particular up to 20%, preferably up to 10% of the length of the teeth 103. In particular, the end surface 107 is part of the end regions 110.

[0039] Fig. 1c shows in schematic form a section of a clamping element according to an embodiment of the present invention.

[0040] The clamping element 101c according to Fig. 1c essentially corresponds to the clamping element 101a according to Fig. 1a. In contrast to the clamping element 101a according to Fig. 1a, the teeth 103 of the clamping element 101c are arranged according to Fig. 1c is not twisted. Instead, material is removed from the teeth 103 at the end regions 110, thus creating the bevel of the teeth 103 around the pressure angle 105.

[0041] Fig. 1d shows in schematic form a clamping element according to an embodiment of the present invention.

[0042] The clamping element 101d according to Fig. 1d essentially corresponds to the clamping element 101a according to Fig. 1a. In contrast to the clamping element 101a according to Fig. 1a, the teeth 103 of the clamping element 101d protrude according to Fig. 1d, starting from the base ring 102, not radially inward, but radially outward. The diameter 111 of the base ring 102 of the clamping element 101d may be larger than the diameter of the base ring 102 of the clamping element 101a according to Fig. 1a. In this way, the clamping element 101a can be Fig. 1a into the clamping element 101d according to Fig. 1d. The teeth 103 of the clamping element 101d according to Fig. 1d are also twisted in the opposite direction as the teeth 103 of the clamping element 101a according to Fig. 1a.

[0043] A gap 113 is provided between each of the teeth 103 so that the teeth can bend and twist individually.

[0044] Fig. 2 shows in schematic form a central release mechanism according to an embodiment of the present invention.

[0045] The central release mechanism 201 comprises a cylinder 1 and a working piston 2. The working piston 2 is axially displaceable within the cylinder 1. For this purpose, a fluid—for example, air—can be injected into a pressure chamber 4, forcing the working piston 2 out of the cylinder 1. A release mechanism 16 is arranged on the working piston 2, on which, for example, a clutch disc or pressure plate can be arranged. Thus, the clutch disc can be moved axially by extending the working piston 2, thereby actuating the clutch. The release mechanism 16 is rotatably mounted on the working piston 2 by a bearing 17.

[0046] The working piston 2 is designed in two parts and comprises a pressure piston 5 and an actuating piston 6. The pressure piston 5 rests against the pressure chamber 4, so that the pressure piston 5 is moved out of the cylinder when a fluid is pressed into the pressure chamber 4. By means of an abutment element 19, the pressure piston 5 then presses against a clamping element 101. The clamping element 101 is thereby clamped in the actuating piston 6 and thus displaces the actuating piston 6. In this way, a movement of the pressure piston 5 is transmitted to the actuating piston 6. The clamping element 101 thus ensures that the pressure piston 5 and the actuating piston 6 are axially fixed to one another during the actuation of the pressure piston 5.

[0047] The working piston 2, pressure piston 5, actuating piston 6, releaser 16, cylinder 1 and stop element 9 are concentrically designed.

[0048] The clamping element 101 comprises an inner clamping element 101a with an inner base ring 102a and an outer clamping element 101d with an outer base ring 102b, wherein teeth 103 protrude from the base rings 102a, 102b. The clamping element 101 can in particular be the clamping element 101a according to Fig. 1a and the clamping element 101d according to Fig. 1d. When the pressure piston 5 is extended, the abutment element 19 contacts the base rings 102a, 102b. Since the teeth 103 of the clamping element 101 have a portion in the axial direction and thus protrude "obliquely" from the base rings 102a, 102b, the teeth 103 are pressed outwards against the actuating piston 6 upon contact of the abutment element 19, thus creating a clamping effect. A radially outer and radially inner thread 10a, 10b of the actuating piston 6 also prevents the clamping element 101 from being axially displaced. For this purpose, the teeth 103 engage in the outer and inner threads 10a, 10b and thus prevent the clamping element 101 from being axially displaced through a positive and frictional connection. The thread pitch of the threads 10a, 10b correlates with the generated clamping force.In particular, the outer thread 10a can have an opposite thread direction to the inner thread 10b, so that the two base rings 102a, 102b cannot drag each other along.

[0049] To increase the clamping effect, a preload element 3—here in the form of a spring—is provided, which presses indirectly on the clamping element 101. The spring is arranged on an intermediate element 8, which presses on a retaining element 13. The retaining element 13 transmits the force of the spring 3 evenly to the clamping element 101. The retaining element 13 has the form of an annular disc arranged between the spring 3 and the clamping element 101. In addition, the retaining element 13 can have a profile corresponding to the twisted teeth 103, so that the retaining element 13 can rest flat against the teeth 103.

[0050] The clutch disc can wear over time. To compensate for this wear, an adjustment device 18 is provided. The adjustment device 18 comprises a locking device 7, which enables or prevents axial adjustment of the pressure piston 5 relative to the actuating piston 6.

[0051] A stop element 9 is provided for the adjustment process. The stop element 9, together with the clamping element 101, forms part of the locking device 7. The stop element 9 has a contact surface 12 with which it can press against the teeth 103 of the clamping element 101. When the stop element 9 presses against the teeth 103, the preload by the spring 3 is released and the clamping element 101 is largely rendered "force-free." This allows an axial displacement of the clamping element 101 relative to the actuating piston 6. In this case, a movement of the outer clamping element 101d can also be transmitted to the inner clamping element 101a by the retaining element 13. When the clamping element 101 is axially displaced, the length that the pressure piston 5 must travel until it strikes the clamping element 101 changes. Thus, the relative position between the pressure piston 5 and the actuating piston 6 has changed, so that the dead volume has also changed.In this way, the dead volume of the central release mechanism 201 can be adjusted.

[0052] By means of the disc spring 11, which rests against a projection 15, the stop element 9 is pressed back into a rest position after the adjustment process.

[0053] When the pressure piston 5 is in Fig. 2 is moved to the left, the abutment element 19 of the pressure piston 5 presses centrally onto the clamping element 101 and reinforces the clamping of the clamping element 101 in the actuating piston 6. The stop element 9 is also moved to the left by the pressure piston 5, whereby the disc spring 11 prevents the stop element 9 from pressing with its stop surface 12 onto the clamping element 101. In other words, only a limited relative movement between the pressure piston 5 and the stop element 9 is permitted. If, due to wear, the actuating piston 6 together with the clamping element 101 in Fig. 2 is pressed to the right, the contact surface 12 of the stop element 9 releases the clamping of the clamping element 101.

[0054] Fig. 3 shows in schematic form a section of a central release mechanism according to an embodiment of the present invention.

[0055] The central release bearing 301 according to Fig. 3 essentially corresponds to the central release bearing 201 according to Fig. 2. The central release bearing 301 according to Fig. 3 differs from the central releaser 201 according to Fig. 2 in that the teeth 103 of the clamping element 101 of the central release mechanism 301 are arranged according to Fig. 3 are twisted only in the end regions 110. In particular, the clamping element 101 according to Fig. 3 the clamping element 101b according to Fig. 1b. This results in a uniform contact area 112 in front of the end areas 110, against which the retaining element 13 can rest. The retaining element 13 thus rests not only on the outer protruding edges of the twisted teeth 103, but also on a flat contact area 112.

[0056] Fig. 4 shows in schematic form a section of a central release mechanism according to an embodiment of the present invention.

[0057] The central release bearing 401 according to Fig. 4 essentially corresponds to the central release bearing 201 according to Fig. 2. The central release bearing 401 according to Fig. 4 differs from the central releaser 201 according to Fig. 2 in that the retaining element 13 of the central release mechanism 401 according to Fig. 4 does not rest on the teeth 103, but rather on the base rings 102a, 102b of the clamping element 101. The advantage of this is that the teeth 103 can be twisted over their entire length and yet a flat contact can be provided between the retaining element 13 and the clamping element 101. In this case, the retaining element 13 is designed as an annular disc having a central indentation 20 with which the retaining element 13 presses against the clamping element 101.

[0058] Fig. 5 shows in schematic form a clamping element in a central release mechanism according to an embodiment of the present invention.

[0059] Shown is a section of the central releaser according to Fig. 2. The clamping element 101 has twisted teeth 103, so that the teeth 103 have a pressure angle. This pressure angle corresponds to the thread pitch of the inner thread 10b and / or the outer thread 10a, so that the teeth 103 can engage with the inner thread 10b and / or the outer thread 10a.

[0060] This allows the clamping element 101 to engage the actuating piston 6 on both sides and clamp it. The threads 10a, 10b increase the clamping force, so that the friction coefficient of the surfaces of the clamping element 101 and / or actuating piston 6 can be reduced without providing an unduly weak clamping force.

[0061] The clamping element 101 is divided into two parts: an inner clamping element 101a and an outer clamping element 101d. The inner and outer clamping elements 101a, 101d are decoupled from each other, allowing both to deform during clamping without creating internal stresses, thus enabling secure clamping.

[0062] The clamping element 101 is not firmly connected to the actuating piston 6, but is mounted in a floating manner in it.

[0063] Fig. 6 shows in schematic form a stop element according to an embodiment of the present invention.

[0064] The stop element 9 has a contact area 12 with which it can contact the teeth of a clamping element. The contact area 12 has a sawtooth profile. This profile corresponds to the bevel or torsion of the teeth of the clamping element, allowing the stop element 9 to be arranged flat against the teeth.

[0065] In particular, the retaining element 13 can also be Fig. 2 have a corresponding sawtooth profile in order to be able to lie flat against the teeth.

[0066] Fig. 7 shows in schematic form steps of a method according to an embodiment of the present invention.

[0067] By means of the method, a clamping element can be produced, in particular a clamping element according to the Fig. 1a-d.

[0068] In step S1, a clamping element is provided, comprising a base ring and a plurality of teeth protruding from the base ring, with a gap formed between each of the teeth. The base ring with the teeth can, for example, be a deep-drawn part. The clamping element can, for example, have a thickness of 1 mm to 5 mm.

[0069] In a further optional step S2, the teeth are bent by an angle of attack in the direction of a central axis of the base ring. Alternatively or additionally, the teeth can already be bent, in particular at least partially bent, on the base ring.

[0070] In a further step S3, at least the end regions of the teeth are twisted or chamfered along an axis in which the teeth protrude from the base ring. For example, the teeth can be machined in their end regions, resulting in chamfered ends. It is also conceivable for the teeth to be twisted over their entire length or at least in their end regions.

[0071] At least one of the embodiments of the invention can realize at least one of the following advantages and / or can realize at least one of the following features: - Increased clamping force. - Adjustable clamping force. - Less installation space for a defined clamping force. - Better distribution of the clamping force and thus less stress on the clamping element

[0072] Although the present invention has been described using preferred embodiments, it is not limited thereto but can be modified in many ways. Reference symbol 1 cylinder 2 working pistons 3 Preload element 4 Printing room 5 pressure pistons 6 adjusting pistons 7 Locking device 8 Intermediate element 9 Stop element 10a external thread 10b internal thread 11 Disc spring 12 Contact surface 13 Retaining element 15 lead 16 releasers 17 camps 18 Adjustment device 19 Kick-off element 20 indentation 101 clamping element 101a, b clamping element 101c, d clamping element 102 base ring 102a inner base ring 102b outer base ring 103 teeth 104 angle of attack 105 pressure angle 106 Longitudinal axis of the teeth 107 End surface of the teeth 108 Main direction of extension of the end face 109 longer edge of the end face 110 End area of ​​the teeth 111 Diameter of the base ring 112 flat contact area 113 gap 201 central release bearing 301 central release bearing 401 central release bearing

Claims

[1] Clamping element (101) for a central release (201) comprising a base ring (102) and a plurality of teeth (103) projecting from the base ring (102), wherein a gap (113) is provided between each of the teeth (103), characterized by that the teeth (103) each have a radially inner or radially outer surface (107) at their end regions (110), wherein the radially inner and / or radially outer surfaces (107) each have a main extension direction (108), wherein at least the end regions (110) of the teeth (103) are designed such that the main extension direction (108) of the inner or outer surface (107) of a tooth (103) has a pressure angle (105) to a circumferential direction of the clamping element (101). [2] Clamping element (101) according to claim 1, characterized by that the teeth (103) are twisted at least in end regions (110) of the teeth (103). [3] Clamping element (101) according to claim 2, characterized bythat the teeth (103) are twisted over at least 70%, preferably at least 80%, in particular at least 90%, of their length. [4] Clamping element (101) according to one of claims 1 to 3, characterized by that the base ring (102) and / or the teeth (103) are made at least partially, in particular completely, of metal, in particular sheet metal. [5] Clamping element (101) according to one of claims 1 to 4, characterized by that the teeth (103) protrude from the base ring (102) at an angle of attack (104) of 5 degrees or more and 50 degrees or less, preferably of 10 degrees or more and 40 degrees or less, in particular of 20 degrees or more and 30 degrees or less to the plane of the base ring (102). [6] Clamping element (101) according to one of claims 1 to 5, characterized bythat the base ring (102) comprises an inner base ring (102a) and an outer base ring (102b), wherein the teeth (103) protrude from both the inner base ring (102a) and the outer base ring (102b). [7] Clamping element (101) according to claim 6, characterized by that the inner base ring (102a) is rotatable in the circumferential direction relative to the outer base ring (102b), wherein the teeth (103) arranged on the inner base ring (102a) are twisted in the opposite direction to the teeth (103) arranged on the outer base ring (102b). [8] Central release mechanism (201) for actuating a clutch, comprising a cylinder (1), a working piston (2) and a preloading element (3), wherein the cylinder (1) and the working piston (2) are designed to be axially movable relative to one another and together delimit a variable pressure chamber (4), wherein the working piston (2) has a pressure piston (5) and an actuating piston (6), wherein a locking device (7) is arranged which is designed to release or block an axial relative movement between the pressure piston (5) and the actuating piston (6), wherein the locking device (7) has a clamping element (101) and a stop element (9), wherein the clamping element (101) is arranged on the actuating piston (6) and is designed to establish a fixed, but detachable, connection with the actuating piston (6) by clamping, wherein the pressure piston (5) is designed to be supported on the clamping element (101) during a disengagement process,wherein the stop element (9) is designed to release a clamping of the clamping element (101), , characterized by that the actuating piston (6) has at least one thread (10a, 10b), wherein teeth (103) of the clamping element (101) can be brought into engagement with the at least one thread (10a, 10b) of the actuating piston (6), in particular wherein the clamping element (101) is designed according to one of claims 1-7. [9] Central release mechanism (201) according to claim 8, characterized by that the actuating piston (6) has two threads (10a, 10b), wherein the threads (10a, 10b) are formed in opposite directions. [10] Central release mechanism (201) according to claim 8 or 9, characterized by that the working piston (2), the stop element (9), the clutch and / or the cylinder (1) are arranged concentrically to one another. [11] Central release mechanism (201) according to one of claims 8 to 10, characterized byin that the stop element (9) has a contact region (12), wherein the contact region (12) has a profile corresponding to the at least partially planar contact of the, in particular twisted, teeth (103). [12] Central release mechanism (201) according to one of claims 8 to 11, characterized by that the teeth (103) are twisted in an end region of the teeth (103) such that a pressure angle (105) of the teeth (103) approximately corresponds to the pitch of the thread (10a, 10b). [13] Central release mechanism (201) according to one of claims 8 to 12, characterized by that a retaining element (13) is arranged between the pretensioning element (3) and the clamping element (101), wherein the retaining element (13) contacts the clamping element (101) on a base ring (102) of the clamping element (101). [14] Central release mechanism (201) according to one of claims 8 to 12, characterized bythat a retaining element (13) is arranged between the pretensioning element (3) and the clamping element (101), wherein the retaining element (13) contacts the clamping element (101) at the teeth (103) of the clamping element (101). [15] Method for producing a clamping element (101), comprising the steps: - Providing (S1) a clamping element (101) comprising a base ring (102) and a plurality of teeth (103) projecting from the base ring (102), wherein a gap (113) is provided between each of the teeth (103), - Optionally bending the teeth (103) in the direction of a central axis of the base ring (102) by an angle of attack (104), - twisting and / or beveling at least end regions (110) of the teeth (103) along an axis in which the teeth (103) each protrude from the base ring (102).

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