Pump unit facilitating accurate installation of shell

Abstract

The utility model discloses a pump unit facilitating accurate installation of a shell, and belongs to the field of pump units. In the pump unit, a bearing seat comprises a seat main body, an assembling part which extends into a pump shell along the axial direction is arranged on one side, facing the pump shell, of the seat main body in a surrounding manner, and the outer wall of the assembling part is in sealing fit with the inner wall of the pump shell; the peripheral edge of the seat main body is provided with an edge part, the tail end of the pump shell is arranged on the periphery of the assembling part in a sleeving manner and abuts against the edge part from one side, and the edge part is tightly pressed in the end cover part; a positioning guide part is arranged between the edge part and the tail end of the pump shell, and the positioning guide part is used for guiding along the axial mounting direction of the pump shell and blocking a circumferential deflection path of the pump shell relative to the edge part. According to the utility model, the positioning and guiding part is arranged, so that accurate guiding is facilitated when the pump shell is axially mounted, the accuracy of the mounting position of the pump shell is guaranteed, and rotation deviation is effectively prevented.

Description

Technical Field

[0001] This utility model relates to the field of pump unit technology, and more specifically, to a pump unit that facilitates precise installation of the casing. Background Technology

[0002] The pump unit's outer casing mainly consists of the motor housing and the pump body. The motor housing houses the stator assembly, rotor assembly, and other drive components, while the pump body houses the impeller and other flow-through components. A pressure cap, or pump cover, is located at the front end of the pump body. This cover typically has a water inlet for precise alignment with the internal flow channels of the pump body, ensuring unobstructed fluid flow and efficient pump operation.

[0003] In the industry, pump casings are typically installed using an axial clamping method. Installers press the pump casing axially onto the housing, ensuring the pump casing end face is tightly against the bearing seat on the housing end cover side. During the clamping process, the pump casing is prone to misalignment, leading to inaccurate positioning between it and the housing, and further, inaccurate positioning between it and the pump cover. This not only increases installation difficulty but can also affect the pump's sealing performance and operating efficiency. Installation errors may even cause vibration or leakage, reducing the reliability and service life of the canned motor pump. Therefore, improving the installation accuracy of the pump casing is extremely important.

[0004] Patent application CN218624749U discloses a pressure-resistant cylinder limiting device. The pressure-resistant cylinder (pump casing) has a limiting element one, and the end cover has a limiting element two. The limiting element two is located on the movement path of the limiting element one, preventing the limiting element one from moving. This design focuses on limiting the movement between the pump casing and the end cover to reduce the rotation amplitude of the pump casing; however, it does not address the installation accuracy between the pump casing and the machine casing. Utility Model Content

[0005] 1. Technical problem to be solved by the utility model

[0006] In view of the problem that pump casing installation is prone to deviation in the prior art, this utility model aims to provide a pump unit that facilitates precise installation of the casing, which can effectively ensure the positional accuracy between the pump casing and the machine casing and ensure installation precision.

[0007] 2. Technical Solution

[0008] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0009] This utility model provides a pump unit that facilitates precise installation of the casing, comprising:

[0010] The housing has an end cap at its front end;

[0011] Pump housing, the tail end of the pump housing is fitted into the end cover;

[0012] The bearing housing is used to mount the motor shaft. The bearing housing is installed between the machine housing and the pump housing and is pressed into the end cover by the tail end of the pump housing.

[0013] The bearing housing includes a housing body. A mounting portion extending axially into the pump housing is provided around the side of the housing body facing the pump housing. The outer wall of the mounting portion is sealed to the inner wall of the pump housing. The outer periphery of the housing body has an edge portion. The tail end of the pump housing is fitted onto the outer periphery of the mounting portion and abuts against the edge portion from one side, pressing the edge portion tightly within the end cover portion. A positioning guide portion is provided between the edge portion and the tail end of the pump housing. This positioning guide portion guides the pump housing along its axial installation direction and prevents circumferential deflection of the pump housing relative to the edge portion. The positioning guide portion helps to accurately guide the pump housing during axial installation, ensuring the accuracy of the pump housing's installation position and effectively preventing rotational deviation.

[0014] Furthermore, the bearing housing is fixedly connected to the end cover of the pump housing; and / or, a positioning guide is provided between the bearing housing and the end cover, which guides the bearing housing along its axial installation direction and prevents the bearing housing from circumferentially deflecting relative to the end cover. This effectively positions and limits the bearing housing before installation, ensuring its position does not shift. Using the bearing housing as a reference, the pump housing is then effectively positioned and limited, ensuring positional stability.

[0015] Furthermore, a locating boss extending axially is provided on the side of the edge facing the pump casing, and a locating opening is provided in the corresponding area of ​​the tail edge of the pump casing. The locating boss fits into the locating opening, which obstructs the circumferential deflection path of the locating boss. Furthermore, an outer ring extending radially outward is provided around the tail edge of the pump casing, and the locating opening is located on the outer ring. Thus, the cooperation of the locating boss and the locating opening serves as a locating guide, achieving effective positioning of the pump casing and bearing housing. Moreover, the structural modification is simple and easy to implement.

[0016] Furthermore, a protruding positioning block is provided on the side of the edge facing away from the pump casing, and a positioning groove corresponding to the positioning block is provided on the inner wall surface of the end cover facing the edge. The cooperation between the positioning block and the positioning groove serves as a positioning guide between the bearing seat and the end cover of the casing, thereby achieving effective positioning of the bearing seat and the casing.

[0017] Furthermore, a ring-shaped groove is provided around the inner wall surface of the end cap and the edge portion in a circumferential direction. The positioning groove is located within the path of this ring-shaped groove, and a positioning rib is formed at the end of the positioning groove to prevent the deflection path of the positioning block. The ring-shaped groove not only helps to reduce weight in the design, but also simplifies the structure by forming the positioning groove.

[0018] Furthermore, at least two sets of positioning blocks protruding outward are provided on the side of the edge away from the pump casing, and positioning ribs are formed at the end of the positioning groove on the end cover and embedded between the two sets of positioning blocks, which has a bidirectional convex-concave matching positioning effect.

[0019] Furthermore, multiple sets of reinforcing ribs are evenly spaced around the annular groove, effectively increasing the structural strength.

[0020] Furthermore, the pump casing has an outwardly protruding positioning part at the tail end, and the edge facing the pump casing has a corresponding groove that matches the positioning part. The positioning part fits into the groove and is limited, thus achieving the convex-concave fit and guiding positioning of the pump casing and bearing seat.

[0021] Furthermore, the inner wall surface of the end cap facing the edge has an outwardly protruding positioning part, and the edge has a corresponding groove that mates with the positioning part. The positioning part fits into the groove and is positioned accordingly. Similarly, this also achieves convex-concave fit guiding and positioning between the bearing housing and the end cap of the housing.

[0022] 3. Beneficial effects

[0023] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0024] (1) The pump unit of this utility model has a positioning guide between the bearing seat and the pump casing, which guides the pump casing along the axial installation direction and prevents the pump casing from deflecting circumferentially relative to the bearing seat, ensuring the accuracy of its position installation, and further ensuring the accuracy of the installation fit between the pump casing and the machine casing, and between the pump casing and the pump cover, avoiding the situation where the pump cover and the pump casing holes are difficult to align and cannot be installed.

[0025] (2) The pump unit of this utility model is also provided with a positioning guide between the bearing seat and the housing. The double positioning guide is adopted. First, the installation of the bearing seat is positioned and guided to ensure the stability of the installation. On this basis, the positioning guide between the pump housing and the bearing seat is further used to position and guide the installation of the pump housing, so as to achieve precise installation of the pump housing. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the shielded pump structure in the embodiment;

[0027] Figure 2 This is a schematic diagram of the internal cross-sectional structure of the shielded pump in the embodiment;

[0028] Figure 3 for Figure 2 A magnified schematic diagram of the partial structure at point A in the middle;

[0029] Figure 4This is a schematic cross-sectional view of the installation structure of the shielded pump housing in the embodiment;

[0030] Figure 5 for Figure 4 A magnified schematic diagram of the local structure at point B;

[0031] Figure 6 This is a schematic diagram of the pump casing in the embodiment;

[0032] Figure 7 This is a schematic diagram of the bearing housing structure in the embodiment;

[0033] Figure 8 This is a schematic diagram of the bearing housing from the rear view in the embodiment;

[0034] Figure 9 This is a schematic diagram of the casing structure in the embodiment;

[0035] Figure 10 for Figure 9 A magnified schematic diagram of the structure at point C.

[0036] Explanation of the labels in the diagram:

[0037] 100. Housing; 101. End cover; 102. Annular groove; 103. Reinforcing rib; 104. Positioning rib; 105. Positioning groove; 110. Bearing seat; 111. Positioning boss; 112. Seat body; 113. Edge; 114. Assembly part; 115. Positioning block; 116. Fastening bolt;

[0038] 200, Pump casing; 201, Outer ring; 202, Positioning opening; 203, Exhaust port; 204, Water inlet; 300, Pump cover; 301, Sealing bolt. Detailed Implementation

[0039] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings.

[0040] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "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 utility model 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 utility model.

[0041] Furthermore, 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 fixed connections, detachable connections, or integral connections; they can be mechanical connections or electrical connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection of two components. The terms "first," "second," "third," and "fourth" should also be interpreted broadly, merely distinguishing feature names and not indicating a specific sequential relationship. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0042] The present invention will be further described below with reference to the embodiments.

[0043] Example

[0044] Combination Figures 1-10 As shown, this embodiment of a pump unit, which facilitates precise installation of the housing, includes: a housing 100, with an end cover 101 at its front end; a pump housing 200, with its tail end fitted into the end cover 101; and a bearing housing 110 for mounting a motor shaft, the bearing housing 110 being installed between the housing 100 and the pump housing 200 and pressed against the end cover 101 by the tail end of the pump housing 200. Specifically, in this embodiment, the pump unit can be in the form of a mechanical pump, a canned motor pump, etc. The housing 100 houses drive components such as a motor shaft, rotor assembly, and stator assembly. If the pump unit is a canned motor pump, the housing 100 also has a shielding cover that seals and isolates the rotor assembly and the stator assembly. The pump housing 200 houses flow-through components such as an impeller. Generally, an inlet 204 is axially positioned at the center of the front end of the pump casing 200, and an outlet is radially positioned on the circumferential sidewall of the pump casing 200. An exhaust port 203 is also provided on the front wall of the pump casing 200 outside the inlet 204. The front end of the pump casing 200 also has a gland, i.e., a pump cover 300. The pump cover 300 has holes corresponding to the inlet 204 and the exhaust port 203. The inlet 204 protrudes from the center hole of the pump cover 300. After the exhaust port 203 is aligned with the corresponding hole on the pump cover 300, it needs to be sealed and locked using sealing bolts 301. In practice, after the installer mates the bearing housing 110 with the casing 100, the pump casing 200 is then pressed axially against the bearing housing 110 to achieve fixation. The bearing housing 110 is a centrally symmetrical annular structure, requiring no installation positioning and avoiding installation deviations. However, when installing the pump casing 200 and the pump cover 300, if the pump casing 200 is misaligned, the exhaust port 203 may not align with the corresponding hole on the pump cover 300, resulting in the sealing bolt 301 being unable to be installed. This not only increases the installation difficulty but may also affect the pump's sealing performance and operating efficiency, and may even cause vibration or leakage, reducing the reliability and service life of the canned pump.

[0045] This embodiment can effectively alleviate the above problems. Specifically, the bearing housing 110 includes a housing body 112, combined with... Figures 3 to 8 As shown, the main body 112 has a mounting portion 114 extending axially into the pump housing 200 on the side facing the pump housing 200. The outer wall of the mounting portion 114 is sealed to the inner wall of the pump housing 200, as shown in the figure. Figure 3 A sealing ring can be arranged around the two parts; the outer peripheral edge of the seat body 112 has an edge portion 113, and the tail end of the pump housing 200 is fitted onto the outer periphery of the mounting portion 114 and abuts against the edge portion 113 from one side, pressing the edge portion 113 into the end cover portion 101; wherein, a positioning guide portion is provided between the edge portion 113 and the tail end of the pump housing 200, which guides along the axial installation direction of the pump housing 200 and prevents the circumferential deflection path of the pump housing 200 relative to the edge portion 113. By providing the positioning guide portion, the pump housing 200 can be effectively guided during the axial installation stage and prevented from circumferentially deflecting, ensuring its positional installation accuracy and further ensuring the accuracy of the installation fit with the pump cover 300.

[0046] More preferably, to ensure the positional stability of the bearing housing 110 and prevent subsequent installation accuracy from being affected by the positional displacement of the bearing housing 110, the bearing housing 110 can be fixedly connected to the end cover portion 101 of the housing 100 first, such as by using bolts to tighten the bearing housing 110 to the end cover portion 101 of the housing 100. Under the premise that the position of the bearing housing 110 is stable, accurate positioning can be achieved by using the positioning guide portion between the bearing housing 110 and the pump housing 200. Alternatively, a positioning guide portion can be provided between the bearing housing 110 and the end cover portion 101. This positioning guide portion guides along the axial installation direction of the bearing housing 110 and prevents the circumferential deflection path of the bearing housing 110 relative to the end cover portion 101. This involves employing a dual-set positioning and guiding system. First, the positioning guide between the bearing housing 110 and the end cover 101 is used to position and guide the installation of the bearing housing 110, ensuring installation stability. Then, the positioning guide between the pump housing 200 and the bearing housing 110 is used to further position and guide the installation of the pump housing 200, achieving precise installation of the pump housing 200. Alternatively, in addition to the above dual-set positioning and guiding system, the bearing housing 110 can also be simultaneously fixedly connected to the end cover 101 of the housing 100 to achieve a stable connection.

[0047] In practice, there are various implementation schemes for the positioning guide between the pump casing 200 and the bearing housing 110, such as combining Figures 3-8A positioning boss 111 extending axially is provided on the side of the edge portion 113 facing the pump housing 200. A positioning opening 202 is provided in the corresponding area of ​​the tail edge of the pump housing 200. The positioning boss 111 fits into the positioning opening 202, and the positioning opening 202 obstructs the circumferential deflection path of the positioning boss 111. The positioning boss 111 and the positioning opening 202 cooperate to form a positioning guide portion. Further preferred embodiment reference Figure 6 An outer ring 201 extending radially outward is provided around the rear edge of the pump housing 200, and a positioning opening 202 is formed on the outer ring 201. During installation, the outer ring 201 abuts and presses against the edge 113 of the bearing housing 110. The outer ring 201 not only increases the abutment area, ensuring stable installation, but also facilitates the setting of the positioning opening 202, ensuring the strength of the pump housing 200 itself, without requiring significant adjustments to the structure of the pump housing 200, making implementation simple and easy. The positioning boss 111 fits into the positioning opening 202 to limit the deflection of the pump housing 200 relative to the bearing housing 110. At this time, refer to... Figure 3 Furthermore, the fastening bolts 116 can be used to pass radially downward through the end cover 101 and be threaded onto the positioning bosses 111, thereby achieving a secure installation of the bearing housing 110 and the end cover 101, while ensuring the stability of the bearing housing 110's position and preventing deflection. Moreover, the bottom end of the fastening bolts 116 will not extend to contact the pump housing 200, thus not affecting the axial disassembly and assembly process of the pump housing 200. This method is convenient to operate, simple in structure, easy to implement, and low in cost. In practice, to ensure uniform guidance, multiple sets of positioning bosses 111 can be evenly spaced circumferentially on the edge 113 of the bearing housing 110, corresponding to the guiding engagement with the pump housing 200.

[0048] Similarly, the positioning guide between the pump housing 200 and the bearing housing 110 can also be configured in the reverse manner. Specifically, a positioning part protruding outwards is provided at the tail end of the pump housing 200. For instance, the positioning part can be provided on the outer ring 201, and the edge 113 of the bearing housing 110 has a corresponding groove on the side facing the pump housing 200 that mates with the positioning part. The positioning part is then fitted into this groove to achieve guidance and limiting. This also achieves effective guidance and limiting between the pump housing 200 and the bearing housing 110, and the structure is simple and easy to implement. Multiple sets can also be arranged circumferentially for guidance and limiting. Other positioning and guiding structures can also be used to achieve guidance and limiting, which will not be elaborated upon here.

[0049] In practice, there are various implementation schemes for the positioning guide between the bearing housing 110 and the end cover portion 101 of the housing 100, such as, see reference Figures 8 to 10As shown, the edge portion 113 of the bearing housing 110, facing away from the pump casing 200, has an outwardly protruding positioning block 115. The end cover portion 101 of the casing 100 has a corresponding positioning groove 105 on its inner wall surface facing the edge portion 113, which mates with the positioning block 115. The positioning block 115 and the positioning groove 105 cooperate to form a positioning guide for guiding and limiting. Similarly, multiple sets of positioning guides can be arranged circumferentially between the edge portion 113 of the bearing housing 110 and the end cover portion 101 of the casing 100. In practice, for the same set of positioning guides, guidance can be achieved using a single positioning block 115 or multiple positioning blocks 115. When using a single set of positioning blocks 115, the inner walls at both ends of the corresponding single positioning groove 105 limit the positioning block 115 to prevent deflection. The length of the positioning groove 105 is adapted to the length of the positioning block 115. When using multiple positioning blocks 115, as shown in the reference... Figure 8 and Figure 9 As shown, the edge portion 113, on the side opposite to the pump casing 200, has two sets of outwardly protruding positioning blocks 115. The gap between the two sets of positioning blocks 115 forms a groove area. Correspondingly, two positioning grooves 105 are formed on the end cover portion 101. The separating rib between the two positioning grooves 105 forms a positioning rib 104, which is embedded in the groove area between the two adjacent sets of positioning blocks 115. At this time, the positioning rib 104 in the middle is used to prevent rotation and limit the positioning blocks 115 on the left and right sides. The length of the positioning grooves 105 on both sides can be greater than the length of the positioning blocks 115. At this time, the positioning blocks 115 and the positioning grooves 105 form a convex-concave fit for limiting, and the positioning rib 104 and the positioning blocks 115 also form a convex-concave fit for limiting, forming a bidirectional limiting structure with simple structure and high stability.

[0050] Furthermore, an annular groove 102 is provided circumferentially around the inner wall surface of the end cap portion 101 of the housing 100, which faces the edge portion 113 of the bearing seat 110. The positioning groove 105 is located within the path of the annular groove 102, and a positioning rib 104 is formed at the end of the positioning groove 105 to obstruct the deflection path of the positioning block 115. In practical processing, opening an annular groove 102 on the end cap portion 101 can simplify the shape and facilitate weight reduction processing. At this time, the positioning groove 105 is formed by using the original annular groove 102, which further simplifies structural adjustment and reduces design costs. Furthermore, multiple sets of reinforcing ribs 103 are evenly spaced around the annular groove 102, which can effectively improve the structural strength. In practice, according to the structural design requirements, the reinforcing ribs 103 can also be used as positioning ribs 104, so that they have both structural lifting and guiding and limiting effects. Furthermore, the original structure is used for guiding and limiting, simplifying structural adjustment and reducing design costs. Alternatively, a positioning rib 104 can be added in addition to the original reinforcing rib 103. The positioning rib 104 also has the functions of structural lifting and guiding and limiting.

[0051] Similarly, the positioning guide between the bearing housing 110 and the end cover 101 of the housing 100 can also be configured in the reverse manner. For example, the end cover 101 of the housing 100 has an outwardly protruding positioning part on the inner wall surface of the edge 113 facing the bearing housing 110, and the edge 113 has a corresponding groove that mates with the positioning part. The positioning part fits into the groove and is limited in position. Other guiding and limiting methods can also be used, which will not be described in detail.

[0052] The pump unit in this embodiment, through simple adjustments to the original structural design of the unit, can effectively guide and limit the axial installation process of the pump casing 200 and the bearing seat 110, ensuring the accuracy and stability of its installation position, and also ensuring the precise fit between the pump casing 200 and the pump cover 300, thereby effectively improving the installation quality and efficiency and ensuring the stable operation of the pump unit.

[0053] The scope of protection of this utility model is defined only by the claims. Thanks to the teachings of this utility model, those skilled in the art will readily recognize that alternative structures to the disclosed structure can be used as feasible alternative implementations, and that the disclosed implementations can be combined to produce new implementations, which also fall within the scope of the appended claims.

Claims

1. A pump unit that facilitates precise installation of the casing, comprising: The housing (100) has an end cap (101) at its front end; Pump housing (200), the tail end of pump housing (200) is fitted into end cover (101); The bearing housing (110) is used to install the motor shaft. The bearing housing (110) is installed between the housing (100) and the pump housing (200) and is pressed into the end cover (101) by the tail end of the pump housing (200). The bearing housing (110) is characterized in that: the bearing housing (110) includes a housing body (112), and a mounting part (114) extending axially into the pump housing (200) is provided around the side of the housing body (112) facing the pump housing (200). The outer wall of the mounting part (114) is sealed to the inner wall of the pump housing (200). The outer peripheral edge of the housing body (112) has an edge part (113). The tail end of the pump housing (200) is fitted onto the outer periphery of the mounting part (114) and abuts against the edge part (113) from one side, pressing the edge part (113) into the end cover part (101). The edge part (113) and the tail end of the pump housing (200) have a positioning guide part, which guides the pump housing (200) along the axial installation direction and prevents the circumferential deflection path of the pump housing (200) relative to the edge part (113).

2. The pump unit according to claim 1, which facilitates precise installation of the casing, is characterized in that: The bearing housing (110) is fixedly connected to the end cover (101) of the housing (100); Or / and, a positioning guide is provided between the bearing housing (110) and the end cover portion (101), which guides the bearing housing (110) in the axial mounting direction and obstructs the circumferential deflection path of the bearing housing (110) relative to the end cover portion (101).

3. A pump unit according to claim 1 or 2 that facilitates precise installation of the casing, characterized in that: The edge portion (113) facing the pump housing (200) is provided with a positioning boss (111) extending axially. The corresponding area of ​​the tail edge of the pump housing (200) is provided with a positioning opening (202). The positioning boss (111) is fitted into the positioning opening (202), and the positioning opening (202) obstructs the circumferential deflection path of the positioning boss (111).

4. The pump unit according to claim 3, which facilitates precise installation of the casing, is characterized in that: The rear edge of the pump casing (200) is surrounded by an outer ring (201) that extends radially outward, and a positioning opening (202) is opened on the outer ring (201).

5. A pump unit for easy and precise installation of the casing according to claim 2, characterized in that: The edge portion (113) is provided with an outwardly protruding positioning block (115) on the side away from the pump housing (200), and the end cover portion (101) is provided with a positioning groove (105) corresponding to the positioning block (115) on the inner wall surface facing the edge portion (113).

6. A pump unit according to claim 5 that facilitates precise installation of the casing, characterized in that: An annular groove (102) is provided around the inner wall surface facing the end cap (101) and the edge portion (113) in the circumferential direction. The positioning groove (105) is located in the path of the annular groove (102), and a positioning rib (104) is formed at the end of the positioning groove (105) to obstruct the deflection path of the positioning block (115).

7. A pump unit according to claim 5 that facilitates precise installation of the casing, characterized in that: The edge portion (113) is provided with at least two sets of outwardly protruding positioning blocks (115) on the side opposite to the pump housing (200), and the end of the positioning groove (105) on the end cover portion (101) is provided with positioning ribs (104) that are embedded between the two adjacent sets of positioning blocks (115).

8. A pump unit according to claim 6 that facilitates precise installation of the casing, characterized in that: Multiple sets of reinforcing ribs (103) are evenly spaced around the annular groove (102).

9. A pump unit according to claim 1 that facilitates precise installation of the casing, characterized in that: The pump housing (200) has an outwardly protruding positioning part at the tail end, and the edge part (113) facing the pump housing (200) has a corresponding groove that matches the positioning part. The positioning part fits into the groove and is limited.

10. A pump unit for easy and precise installation of the casing according to claim 2, characterized in that: The end cap (101) has an outwardly protruding positioning part on the inner wall surface facing the edge part (113), and the edge part (113) has a corresponding groove that cooperates with the positioning part. The positioning part is fitted into the groove and is limited in position.

Images