Grinding tooling

Abstract

The utility model discloses a kind of matching grinding tool, it is applied to the sealing surface of the valve body and valve clack of axial flow valve cooperation is matched and ground, matching grinding tool can be placed in the valve cavity of valve body, matching grinding tool includes mounting bracket, mounting bracket bottom end is detachably connected to valve clack;Guiding sleeve is slidably arranged on mounting bracket along vertical direction, the outer circumferential surface of the sealing portion of valve body is movably sleeved in the bottom of guiding sleeve, and it can be vertically direction as rotary axis rotation setting in the sealing portion of valve body;Spring is arranged between guiding sleeve and mounting bracket, spring has the biasing force of driving mounting bracket to move away from guiding sleeve along vertical direction;Adjusting assembly is provided on mounting bracket, adjusting assembly is used to adjust the pre-compression of spring, the utility model can avoid the sealing surface of valve clack and valve body to be caused by excessive pressure bruise or scratch, ensure the sealing effect of axial flow valve sealing surface.

Description

Technical Field

[0001] This utility model relates to the field of valve manufacturing technology, specifically to a grinding tool. Background Technology

[0002] In the manufacturing process of large-diameter axial flow check valves, the sealing performance of the valve disc and valve body is crucial due to their separate design. To ensure a good fit between the sealing surfaces, the sealing surfaces of the valve disc and valve body need to be ground together.

[0003] Existing grinding devices cannot effectively adjust the weight of the valve disc applied to the valve body during the grinding process of the valve disc and valve body. An excessively heavy valve disc is very likely to cause pressure or scratches on the valve body sealing surface, resulting in poor sealing effect of the axial flow valve sealing surface. Utility Model Content

[0004] This utility model provides a grinding fixture that solves the technical problem that existing grinding devices are not easy to effectively adjust the weight of the valve disc applied to the valve body. Excessive valve disc weight can easily cause pressure or scratches on the valve body sealing surface, resulting in poor sealing effect of the axial flow valve sealing surface.

[0005] In view of this, the present invention provides a grinding fixture for grinding the sealing surfaces of the valve body and valve disc of an axial flow valve. The grinding fixture can be placed inside the valve cavity of the valve body. The grinding fixture includes: Mounting bracket, with its bottom end detachably connected to the valve disc; A guide sleeve is slidably disposed on the mounting bracket in the vertical direction. The bottom of the guide sleeve is movably sleeved on the outer circumferential surface of the sealing part of the valve body, and can be rotatably disposed on the sealing part of the valve body with the vertical direction as the axis of rotation. A spring is disposed between the guide sleeve and the mounting bracket, and the spring has a biasing force that drives the mounting bracket to move vertically away from the guide sleeve. An adjustment component is provided on the mounting bracket, the adjustment component being used to adjust the pre-compression of the spring.

[0006] The grinding fixture according to this utility model has at least the following beneficial effects: By setting a pre-compressed spring between the guide sleeve and the mounting bracket, the mounting bracket and the valve disc are detachably connected as one unit and can move vertically relative to the sealing part of the guide sleeve and the valve body. During use, the pre-compression of the spring can be flexibly adjusted by adjusting the adjustment component according to actual needs, thereby adjusting the bias pressure applied by the spring to the mounting bracket and the valve disc, and thus accurately controlling the pressure applied by the first sealing surface of the valve disc to the second sealing surface of the valve body. This avoids damage or scratches to the first sealing surface of the valve disc and the second sealing surface of the valve body due to excessive pressure, ensuring the sealing effect of the axial flow valve sealing surface.

[0007] In one optional embodiment, the mounting bracket includes a guide plate and at least two uprights, with a plurality of uprights circumferentially spaced and connected to the top surface of the valve disc in the vertical direction; the guide plate is slidably disposed between the plurality of uprights in the vertical direction, a guide post is disposed at the center of the bottom end of the guide plate, the inner top of the guide sleeve is slidably disposed on the outer peripheral surface of the guide post, the spring is sleeved on the guide sleeve and the guide post, the top end of the spring abuts against the guide plate, and the bottom end of the spring abuts against the lower end of the outer side wall of the guide sleeve.

[0008] In one alternative embodiment, each of the uprights has a first threaded portion at its upper part along the vertical direction, and the adjustment assembly includes an adjusting nut that is threadedly engaged with the first threaded portion, the adjusting nut abutting against the top surface of the guide plate.

[0009] In one optional embodiment, a connecting plate is provided at the lower end of the outer peripheral surface of the guide sleeve, and the bottom end of the spring abuts against the top end of the connecting plate.

[0010] In one optional embodiment, a plurality of equal-height shims are movably fitted onto the outer peripheral surface of the guide sleeve, and the equal-height shims are disposed between the spring and the connecting plate.

[0011] In one alternative embodiment, the connecting plate can be slidably disposed vertically on the outer peripheral surface of the guide sleeve and locked by a locking assembly.

[0012] In one alternative embodiment, at least two first threaded holes are provided circumferentially spaced on the sidewall of the connecting plate, each first threaded hole penetrating the connecting plate radially along the guide sleeve; the locking assembly includes fastening screws that match the first threaded holes.

[0013] In an alternative embodiment, a drive mechanism is further included, which drives the valve disc, the mounting bracket, and the guide sleeve to rotate together relative to the sealing portion of the valve body.

[0014] In one optional embodiment, the valve disc has two through slots spaced circumferentially at its top vertical position, and the drive mechanism includes a U-shaped drive member, the two ends of which are detachably inserted into the two through slots.

[0015] In one alternative embodiment, a thrust ball bearing is provided between the guide sleeve and the sealing portion. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a cross-sectional front view structural diagram of this embodiment.

[0018] Explanation of reference numerals in the attached figures: 100 - Valve body, 110 - Valve cavity, 120 - Sealing part, 121 - Fourth sealing surface, 130 - Second sealing surface; 200 - Valve disc, 210 - Through groove, 220 - First sealing surface, 230 - Third sealing surface; 300 - Guide sleeve, 310 - Thrust ball bearing; 400-Spring; 510-Guide plate, 511-Guide post, 520-Upright pole, 521-First threaded part, 522-Anti-slip pad; 600 - Adjusting nut; 700 - Connecting plate, 710 - Equal height washer, 720 - Fastening screw; 800-U type drive component. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0020] In the description of this embodiment, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this embodiment. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] In the description of this embodiment, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment according to the specific circumstances.

[0022] The following is combined Figure 1 The following describes embodiments of the present invention.

[0023] According to an embodiment of this utility model, a grinding fixture is provided for grinding the sealing surfaces of the valve body 100 and valve disc 200 of an axial flow valve. The grinding fixture can be placed inside the valve cavity 110 of the valve body 100. The grinding fixture includes a mounting frame, the bottom end of which is detachably connected to the valve disc 200. A guide sleeve 300 is slidably disposed on the mounting frame in the vertical direction. The bottom of the guide sleeve 300 is movably sleeved on the outer peripheral surface of the sealing part 120 of the valve body 100 and can be rotatably disposed on the sealing part 120 of the valve body 100 with the vertical direction as the axis of rotation. A spring 400 is disposed between the guide sleeve 300 and the mounting frame. The spring 400 has a biasing force that drives the mounting frame to move away from the guide sleeve 300 in the vertical direction. An adjustment component is disposed on the mounting frame to adjust the pre-compression of the spring 400.

[0024] In this embodiment, the grinding fixture has a pre-compressed spring 400 between the guide sleeve 300 and the mounting bracket. The mounting bracket and the valve disc 200 are detachably connected as a whole and can move vertically relative to the guide sleeve 300 and the sealing part 120 of the valve body 100. During use, the pre-compression of the spring 400 can be flexibly adjusted by adjusting the components according to actual needs, thereby adjusting the bias pressure applied by the spring 400 to the mounting bracket and the valve disc 200. This precisely controls the pressure applied by the first sealing surface 220 of the valve disc 200 to the second sealing surface 130 of the valve body 100, avoiding damage or scratches to the first sealing surface 220 of the valve disc 200 and the second sealing surface 130 of the valve body 100 due to excessive pressure, and ensuring the sealing effect of the axial flow valve sealing surface.

[0025] It is understood that when this embodiment is placed in the valve cavity 110 of the valve body 100 for grinding, the central axes of the valve body 100, valve disc 200, sealing part 120 and guide sleeve 300 overlap.

[0026] It should be noted that, because the bottom of the guide sleeve 300 is fitted onto the sealing part 120 of the valve body 100, the guide sleeve 300 will not move vertically relative to the sealing part 120 of the valve body 100 under the action of gravity and the biasing force of the spring 400. Furthermore, the valve disc 200 can move vertically along with the guide sleeve 300 along with the mounting bracket. Therefore, the biasing force applied by the spring 400 to the valve disc 200 and the mounting bracket can offset part of the weight of the valve disc 200 and the mounting bracket. That is, the greater the pre-compression of the spring 400, the more gravity it can offset, thus reducing the pressure exerted by the first sealing surface 220 of the valve disc 200 on the second sealing surface 130 of the valve body 100. Especially during the grinding process of the heavier valve disc 200 and the sealing surface of the valve body 100, it effectively avoids excessive pressure causing damage or scratches to the sealing surfaces of the valve disc 200 and the valve body 100. This is suitable for high-quality manufacturing of heavy, large-diameter axial flow valves.

[0027] It should be noted that, in the process of grinding the sealing surfaces of the valve body 100 and valve disc 200 of the axial flow valve using this embodiment, the mounting bracket and valve disc 200 are first detachably connected as one unit. Then, the pre-compression of the spring 400 is flexibly adjusted according to actual needs using the adjusting component. Next, the grinding fixture equipped with valve disc 200 is placed inside the valve cavity 110 of the valve body 100 until the bottom of the guide sleeve 300 is fitted onto the sealing part 120 of the valve body 100 to achieve rotational engagement. At this time, the first sealing surface 220 of the valve disc 200 and the second sealing surface 130 of the valve body 100 abut against each other. Finally, the valve disc 200 is rotated relative to the sealing part 120 along with the grinding fixture of this embodiment. This allows the sealing surfaces of the valve disc 200 and valve body 100 to be ground under uniform and appropriate pressure, effectively ensuring the fit of the sealing surfaces and greatly improving the sealing performance and product quality of the large-diameter axial flow check valve. It is understandable that when the guide sleeve 300 is fitted onto the set position on the outer peripheral surface of the sealing part 120, the guide sleeve 300 cannot move downward in the vertical direction relative to the sealing part 120, and the sealing surface of the valve disc 200 abuts against the sealing surface of the valve body 100.

[0028] It should be noted that the valve disc 200 has a cylindrical structure. The outer wall of the bottom end of the valve disc 200 is the first sealing surface 220, and the portion of the inner wall of the valve body 100 corresponding to the first sealing surface 220 is the second sealing surface 130. The inner wall of the bottom end of the valve disc 200 is the third sealing surface 230, and the portion of the outer wall of the sealing part 120 corresponding to the third sealing surface 230 is the fourth sealing surface 121. While the first sealing surface 220 and the second sealing surface 130 are abutting and grinding against each other, the third sealing surface 230 and the fourth sealing surface 121 are also abutting and grinding against each other. Because this embodiment can precisely control the pressure applied by the valve disc 200 to the valve body 100, it can avoid damage or scratches to the first sealing surface 220 of the valve disc 200 and the second sealing surface 130 of the valve body 100 due to excessive pressure, and it can also avoid damage or scratches to the third sealing surface 230 of the valve disc 200 and the fourth sealing surface 121 of the sealing part 120 due to excessive pressure.

[0029] It is understood that the valve disc 200 has a central hole through the middle, which is used for the bottom of the guide sleeve 300 to pass through coaxially, so that the inner bottom of the guide sleeve 300 can be movably sleeved on the outer peripheral surface of the top of the sealing part 120, and the guide sleeve 300 can rotate relative to the sealing part 120 (i.e., the valve body 100), so that the valve disc 200 rotates with the valve body 100 in the vertical direction as the axis of rotation, so as to realize the matching of the first sealing surface 220 and the second sealing surface 130, as well as the matching of the third sealing surface 230 and the fourth sealing surface 121.

[0030] It is understood that the guide sleeve 300, spring 400, valve disc 200, valve body 100, and sealing part 120 are coaxially arranged, and their vertical direction is parallel to the axis of the guide sleeve 300. For ease of description, it is referred to as... Figure 1 The vertical direction in the text is described as the vertical direction, but not as a specific limitation thereof.

[0031] In some embodiments, the mounting bracket includes a guide plate 510 and at least two uprights 520, preferably two uprights 520, which are evenly spaced circumferentially connected to the top surface of the valve disc 200 in the vertical direction; the guide plate 510 is slidably disposed between the two uprights 520 in the vertical direction, and a guide post 511 is disposed at the middle of the bottom end of the guide plate 510; the inner top of the guide sleeve 300 is slidably disposed on the outer peripheral surface of the guide post 511; a spring 400 is sleeved on the guide sleeve 300 and the guide post 511; the top end of the spring 400 abuts against the guide plate 510; and the bottom end of the spring 400 abuts against the lower end of the outer side wall of the guide sleeve 300. The guide post 511 and guide sleeve 300 are used to increase the guide connection area, and the spring 400 is sleeved on the outside of the guide sleeve 300 and guide post 511, so that the bias pressure of the spring 400 is applied to the valve disc 200 more evenly, which is conducive to the valve disc 200 and the sealing surface of the valve body 100 being fitted and polished under uniform and appropriate pressure.

[0032] Specifically, the bottom end of the upright 520 is provided with a second threaded part, which engages with the pre-set threaded hole of the valve disc 200. The engagement between the second threaded part and the pre-set thread of the valve disc 200 ensures both the tightness of the connection between the upright 520 and the valve disc 200 and facilitates the assembly and disassembly of the upright 520 and the valve disc 200.

[0033] Specifically, an anti-slip pad 522 is provided between the top surfaces of the upright 520 and the valve disc 200.

[0034] In specific applications, the number of uprights 520 can be reasonably increased or decreased according to the weight of valve disc 200 and the cross-sectional dimensions of valve disc 200 perpendicular to the vertical direction. For example, in other embodiments, the number of uprights 520 may be three, four, or five.

[0035] In some embodiments, the upper part of each upright 520 in the vertical direction is provided with a first threaded portion 521. The adjusting assembly includes adjusting nuts 600 that are threadedly engaged with the first threaded portions 521, and the adjusting nuts 600 abut against the top surface of the guide plate 510. Because the top of the spring 400 always abuts against the bottom surface of the guide plate 510, when the adjusting nut 600 is rotated and rises relative to the upright 520, the biasing force of the spring 400 pushes the guide plate 510 upward to release energy. At this time, the pre-compression of the spring 400 is reduced, which is suitable for grinding the sealing surfaces of the lighter valve disc 200 and valve body 100. When the adjusting nut 600 is rotated and falls relative to the upright 520, the spring 400 is pressed down by the guide plate 510 to store energy. At this time, the pre-compression of the spring 400 is increased, which is suitable for grinding the sealing surfaces of the heavier valve disc 200 and valve body 100. The entire process of adjusting the pre-compression of the spring 400 is simple to operate.

[0036] In some embodiments, a connecting plate 700 is provided at the lower end of the outer peripheral surface of the guide sleeve 300, and the bottom end of the spring 400 abuts against the top end of the connecting plate 700. The connecting plate 700 increases the contact area with the spring 400, so that the spring 400 can apply the biasing force to the valve disc 200 more evenly.

[0037] In some embodiments, a plurality of equal-height washers 710 are movably fitted onto the outer peripheral surface of the guide sleeve 300, and the equal-height washers 710 are disposed between the spring 400 and the connecting plate 700. Considering that the vertical dimension of the first threaded portion 521 is limited, by adding equal-height washers 710 between the spring 400 and the connecting plate 700, the maximum pre-compression of the spring 400 is further increased, thereby making it suitable for fitting the sealing surfaces of the heavier valve disc 200 and valve body 100.

[0038] It is understandable that "several" here refers to one, two, or more than two.

[0039] In some embodiments, the connecting plate 700 can be slidably disposed vertically on the outer peripheral surface of the guide sleeve 300 and locked by a locking assembly. With this configuration, after the wear-resistant tooling of this embodiment is removed from the valve cavity 110 of the valve body 100, the locking assembly can be unlocked and the connecting plate 700 can be removed from the guide sleeve 300. At this time, the number of equal-height shims 710 can be increased or decreased. Then, the connecting plate 700 is placed on the guide sleeve 300 and locked and fixed by the locking assembly. The number of equal-height shims 710 located between the connecting plate 700 and the spring 400 can be flexibly changed, thereby satisfying the need for grinding the sealing surfaces of the valve disc 200 and the valve body 100 with a larger weight range without damaging or scratching the sealing surfaces.

[0040] In some embodiments, at least two first threaded holes are provided circumferentially spaced on the sidewall of the connecting plate 700, preferably two first threaded holes, each first threaded hole radially penetrating the connecting plate 700 along the guide sleeve 300; the locking assembly includes a fastening screw 720 that matches the first threaded hole. When it is necessary to remove the connecting plate 700 from the guide sleeve 300, the fastening screw 720 can be rotated in the first screw hole until the tip of the fastening screw 720 separates from the outer peripheral surface of the guide sleeve 300 to release the locking force, thereby facilitating the movement or removal of the connecting plate 700; when the connecting plate 700 is moved relative to the guide sleeve 300 to a set position, the fastening screw 720 can be rotated in the first screw hole until the tip of the fastening screw 720 abuts against the outer peripheral surface of the guide sleeve 300 to generate friction and achieve locking; the whole process is simple to operate.

[0041] In specific applications, the number of first threaded holes can be reasonably increased or decreased according to the magnitude of the bias force applied by the spring 400 to the connecting plate 700. For example, in other embodiments, the number of first threaded holes may be three, four, or five.

[0042] In some embodiments, the grinding fixture further includes a drive mechanism, which drives the valve disc 200, the mounting bracket and the guide sleeve 300 to rotate together relative to the sealing part 120 of the valve body 100, thereby driving the valve disc 200 to rotate stably relative to the valve body 100, so that the sealing surface of the valve disc 200 rubs against the sealing surface of the valve body 100 to achieve the grinding effect.

[0043] Specifically, the valve disc 200 has two through slots 210 spaced circumferentially at its top vertically. The driving mechanism includes a U-shaped drive member 800, with both ends of the U-shaped drive member 800 detachably inserted into the two through slots 210. Utilizing the structural characteristics of the valve disc 200, by inserting both ends of the U-shaped drive member 800 into the two through slots 210 and rotating the two ends of the U-shaped drive member 800 until they abut against the side walls of the two through slots 210, the valve disc 200 can be driven to rotate stably relative to the valve body 100. Simultaneously, the U-shaped space of the U-shaped drive member 800 allows the mounting bracket to pass through, preventing interference between the U-shaped drive member 800 and the mounting bracket during the rotation of the valve disc 200 relative to the valve body 100.

[0044] In some embodiments, a thrust ball bearing 310 is provided between the guide sleeve 300 and the sealing part 120 to improve the smoothness of the rotation of the guide sleeve 300 relative to the sealing part 120, so that the valve disc 200 can be rotated stably relative to the valve body 100 by a manual drive component 800, so as to realize manual grinding without being constrained by equipment.

[0045] In this embodiment, after the sealing surfaces of the valve body 100 and valve disc 200 are properly ground, the grinding fixture with valve disc 200 is first removed from the valve cavity 110 of the valve body 100. Then, the adjusting nut 600 is removed from the first threaded part 521, the guide plate 510 is removed from the upright 520, the spring 400 is removed, and the upright 520 is removed from the valve disc 200. This allows the ground valve disc 200 to be removed from the grinding fixture of this embodiment, while also disassembling the components of this embodiment for storage.

[0046] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the present invention.

Claims

1. A grinding fixture, used for grinding the mating sealing surfaces of the valve body (100) and valve disc (200) of an axial flow valve, characterized in that, The grinding fixture can be placed inside the valve cavity (110) of the valve body (100), and the grinding fixture includes: Mounting bracket, the bottom end of which is detachably connected to the valve disc (200). The guide sleeve (300) is slidably disposed on the mounting bracket in the vertical direction. The bottom of the guide sleeve (300) is movably sleeved on the outer circumferential surface of the sealing part (120) of the valve body (100), and can be rotatably disposed on the sealing part (120) of the valve body (100) with the vertical direction as the axis of rotation. A spring (400) is disposed between the guide sleeve (300) and the mounting bracket, the spring (400) having a biasing force that drives the mounting bracket to move vertically away from the guide sleeve (300); An adjustment component is provided on the mounting bracket, the adjustment component being used to adjust the pre-compression of the spring (400).

2. The grinding fixture according to claim 1, characterized in that, The mounting bracket includes a guide plate (510) and at least two uprights (520). The uprights (520) are circumferentially spaced and connected to the top surface of the valve disc (200) in the vertical direction. The guide plate (510) is slidably disposed between the uprights (520) in the vertical direction. A guide post (511) is provided at the middle of the bottom end of the guide plate (510). The inner top of the guide sleeve (300) is slidably disposed on the outer circumferential surface of the guide post (511). The spring (400) is sleeved on the guide sleeve (300) and the guide post (511). The top end of the spring (400) abuts against the guide plate (510), and the bottom end of the spring (400) abuts against the lower end of the outer side wall of the guide sleeve (300).

3. The grinding fixture according to claim 2, characterized in that, Each of the uprights (520) has a first threaded portion (521) at its upper part in the vertical direction. The adjustment assembly includes an adjusting nut (600) that is threaded into the first threaded portion (521) and the adjusting nut (600) abuts against the top surface of the guide plate (510).

4. The grinding fixture according to claim 3, characterized in that, A connecting plate (700) is provided at the lower end of the outer peripheral surface of the guide sleeve (300), and the bottom end of the spring (400) abuts against the top end of the connecting plate (700).

5. The grinding fixture according to claim 4, characterized in that, The outer circumferential surface of the guide sleeve (300) is movably fitted with a plurality of equal-height shims (710), which are disposed between the spring (400) and the connecting plate (700).

6. The grinding fixture according to claim 5, characterized in that, The connecting plate (700) can be slidably disposed on the outer peripheral surface of the guide sleeve (300) in a vertical direction and locked by a locking assembly.

7. The grinding fixture according to claim 6, characterized in that, At least two first threaded holes are provided circumferentially at intervals on the side wall of the connecting plate (700), and each first threaded hole penetrates the connecting plate (700) radially along the guide sleeve (300); the locking assembly includes a fastening screw (720) that matches the first threaded hole.

8. The grinding fixture according to claim 1, characterized in that, It also includes a drive mechanism for driving the valve disc (200), the mounting bracket and the guide sleeve (300) to rotate together relative to the sealing portion (120) of the valve body (100).

9. The grinding fixture according to claim 8, characterized in that, The valve disc (200) has two through slots (210) spaced circumferentially at the top of the vertical direction. The driving mechanism includes a U-shaped driving member (800), and the two ends of the U-shaped driving member (800) are detachably inserted into the two through slots (210).

10. The grinding fixture according to claim 1 or 9, characterized in that, A thrust ball bearing (310) is provided between the guide sleeve (300) and the sealing part (120).

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