TWI824644B - Micro linear slide - Google Patents

Abstract

The miniature linear slide rail of the present invention includes a track, a slide block, at least one circulation accessory and a retainer. The slide block is arranged on the track, and the circulation accessory is located on the track and connected to the slide block, so that a circulation channel for the ball running is formed between the circulation accessory, the track and the slide block. The circulation accessory has several turning convex parts, and the retainer has a plate part and Two holding parts. The two ends of each holding part are respectively connected to the plate part by a positioning part. The plate part of the holding part is adjacent to the slider. The positioning parts of the retainer are against the turning convex parts. The holding parts of the retainer are A retaining effect is provided for the running balls, wherein the width of the plate portion of the retainer is smaller than the distance between the turning convex portions of the circulation fitting. Thereby, the miniature linear slide rail of the present invention can optimize the assembly efficiency and thereby achieve the purpose of automated assembly.

Description

Micro linear slide

The present invention relates to linear slide rails, and in particular, to a miniature linear slide rail that can optimize assembly efficiency.

The retainer disclosed in JP 2632126 B2 is a closed curve formed by two locking parts and two straight parts, and the retainer is a metal wire, which is made by segmented molding and then welding or bonding, which is troublesome to manufacture. In addition, Because the overall structure is relatively weak, it is difficult to take and assemble, and it is easily damaged and deformed, resulting in poor holding effect, and may even compress the balls, causing smooth operation.

The retainer disclosed in TW I440784 is composed of a holding part and two hooks. Each end cover is provided with a snap groove corresponding to the hook and a guide surface adjacent to the snap groove. The guide surface is relative to the end cover. It has an inclination angle, and the assembly resistance is reduced by setting the inclination angle. However, the retainer itself is too small and difficult to handle, and the resistance at the end of the guide surface is still large, making assembly difficult. In addition, the retainer has a multi-segment curved configuration that is easily entangled with each other and often requires additional processes for separation, thus increasing hidden costs.

The retainer disclosed in US 5544954 includes a straight part and two arc-shaped locking parts. Since the retainer itself is a small steel wire, it is difficult to take. In addition, when the retainer has two ends, When the arc-shaped locking section is installed in the arc-shaped grooves of the two end caps, it is not only difficult to align, but also requires a certain amount of force to be pressed in, so it is more inconvenient to assemble.

On the other hand, for the Miniature Linear Guide, which is about 1cm in height and 2cm in width (or even smaller), manual work is required when assembling the retainer. However, due to its small size, it requires Due to the limitations of manual work, there is still room for improvement in assembly efficiency and production capacity.

The main purpose of the present invention is to provide a miniature linear slide rail that can optimize assembly efficiency to achieve automated assembly.

In order to achieve the above main purpose, the miniature linear slide rail of the present invention includes a track, a slide block, at least one circulation accessory, a plurality of balls, and a retainer. The slider is slidably disposed on the track, and the slider has an abdomen and two opposite sides connected to the abdomen; the circulation accessory is slidably disposed on the track and connected to the slider, so that A circulation channel is formed between the circulation fitting, the track and each side of the slider. In addition, the circulation fitting has a plurality of turning convex parts; the retainer has a plate part, a plurality of positioning parts and two holding parts. The two ends of each holding part are respectively connected to the plate part with a positioning part, the plate part of the holder is adjacent to the belly of the slider, and the positioning parts of the holding part are against the circulation accessories The turning convex portions, and each holding portion of the retainer is in contact with the balls, wherein the width of the plate portion of the retainer is smaller than the distance between the turning convex portions of the circulating accessories.

From the above, it can be seen that the miniature linear slide rail of the present invention presses the retainer in the direction of the slide block to complete the assembly with the slide block. The assembly is relatively easy, so the assembly efficiency can be improved and the assembly cost can be reduced. In order to achieve the purpose of automated assembly.

Preferably, two side surfaces of the track respectively have a first rolling groove and a retaining groove adjacent to the first rolling groove, and each side of the slide block has a second rolling groove, and the third rolling grooves of the slide block The two rolling grooves correspond to the first rolling grooves of the track one-to-one, so that a load channel is formed between the second rolling grooves of the slider and the first rolling grooves of the track. Each side portion has a non-load channel, and each non-load channel penetrates two opposite end surfaces of the side portion. The number of the circulation accessories is two. Each circulation accessory is provided on two opposite end surfaces of the slider and has two turning convex parts and two return grooves. Each return groove is adjacent to one of the turning convex parts, and each of the two return grooves is The end is connected with one end of the load channel and one end of the non-load channel, so that one load channel, one non-load channel and two return grooves jointly form a circulation channel. Each retaining portion of the retainer is located in the retaining groove of the track and abuts against the balls passing through a load channel.

Preferably, two side surfaces of the track respectively have a first rolling groove and a retaining groove adjacent to the first rolling groove, and each side of the slide block has two mutually parallel second rolling grooves and two opposite second rolling grooves. A return groove, a load channel is respectively formed between a second rolling groove on each side of the slider and one of the first rolling grooves on the track. The number of the circulation accessories is one, and the circulation accessories further have two opposite socket grooves and four turning convex portions. A third rolling groove and two opposed second return grooves are arranged around each socket groove. Two return grooves connect two ends of the third rolling groove, one of the second rolling grooves on each side of the slider corresponds to one of the first rolling grooves of the slide rail, and each side of the slider The other second rolling groove corresponds to the cycle The third rolling groove of the ring accessory, and the first return grooves on each side of the slider correspond to the second return grooves of the circulation accessory, so that the first rolling groove, the second return grooves The rolling groove, the third rolling groove, the first return grooves and the second return grooves together form a circulation channel; each second return groove is adjacent to one of the turning convex portions, and each second return groove Connected to a load channel, each retaining portion of the retainer is located in the retaining groove of the track and abuts against the balls passing through a load channel.

Preferably, the bottom surface of the belly of the slider has a concave portion, and the top surface of the plate portion of the retainer has a convex portion, and the holder is embedded in the concave portion of the slider with the convex portion, so that It can improve the positioning effect between the two.

Preferably, each circulation accessory further has a plurality of positioning blocks. Each positioning block protrudes from a turning protrusion into a groove along the extension direction of the track. Each positioning portion of the retainer is locked. The positioning block is connected to one of the circulation accessories, so that the positioning effect between the two can be improved.

Preferably, the holder further has a plurality of wings, each of which extends from a positioning portion in a direction away from the plate portion and abuts against an outer end surface of the circulation accessory to lift the holder. structural stability.

Preferably, the outer end surface of each circulation fitting has a plurality of positioning posts, and each wing of the retainer has a positioning hole. The retainer is clamped to the positioning holes of the circulation accessories. column, which can improve the positioning effect between the two.

Preferably, the retainer further has a plurality of wings, each of which extends upward from one end of the retaining portion and abuts against the outer end surface of the circulation accessory to enhance the structural stability of the retainer.

Preferably, the cross-sectional shape of the holding part is rectangular, and the width-to-thickness ratio of the holding part is not less than 1.5. This ensures that the holding part has sufficient structural strength and is not easily deformed to provide a good holding effect.

Preferably, the cross-sectional shape of each positioning portion is rectangular, and the length-to-thickness ratio of each positioning portion is not less than 1.5. This ensures that each positioning portion has sufficient structural strength and is not easily deformed to provide a good positioning effect.

The detailed structure, features, assembly or usage of the miniature linear slide provided by the present invention will be described in the subsequent detailed description of the embodiments. However, those with ordinary knowledge in the field of the present invention should understand that these detailed descriptions and specific examples for implementing the present invention are only used to illustrate the present invention and are not intended to limit the scope of the patent application of the present invention.

10:Micro linear slide

10’: Micro linear slide

20: Orbit

22: First rolling groove

24:Retention slot

30:Slider

31:Abdomen

32: Side

33: Second rolling groove

34: Non-load channel

35: concave part

40: Circulation accessories

41: Steering convex part

411: Positioning end face

D: The distance between the steering convex parts

42:Return tank

43: Container

44: Positioning block

45:Outer end face

46: Positioning column

50: Ball

52:Load channel

54: Circulation channel

56: Non-load channel

60: retainer

61: Board

W1: Width of plate part

62: Positioning Department

L: length of positioning part

T2: Thickness of positioning part

63:Maintenance Department

W2: Width of holding part

T1: Thickness of holding part

64:convex part

65: Wing

66: Positioning hole

70: Slider

71:Abdomen

72: Side

73: Second rolling groove

74: First return tank

80: Circulation accessories

81:Socket slot

82:Third rolling groove

83: Second return tank

84: Steering convex part

Figure 1 is a perspective view of a miniature linear slide rail according to the first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the miniature linear slide rail according to the first embodiment of the present invention.

Figure 3 is a cross-sectional view along line 3-3 in Figure 1.

Figure 4 is a cross-sectional view along line 4-4 in Figure 1.

Figure 5 is a partially exploded three-dimensional view of the miniature linear slide rail in the first embodiment of the present invention, omitting the track.

Figure 6 is a combined diagram of Figure 5.

Figure 7 is a bottom view of the miniature linear slide rail omitting the track according to the first embodiment of the present invention.

Figure 8 is a perspective view of the retainer provided by the micro linear slide rail according to the first embodiment of the present invention.

Figure 9 is a cross-sectional view along line 9-9 in Figure 8.

Figure 10 is a cross-sectional view along line 10-10 in Figure 8.

Figure 11 is a partial perspective exploded view of the miniature linear slide rail in the second embodiment of the present invention, omitting the track.

Figure 12 is a cross-sectional view of the micro linear slide rail omitting the track according to the second embodiment of the present invention.

Figure 13 is a partial perspective view of the micro linear slide rail omitting the track according to the third embodiment of the present invention.

Figure 14 is a perspective view of the retainer provided by the micro linear slide rail according to the fourth embodiment of the present invention.

Fig. 15 is a perspective view of a miniature linear slide rail omitting the track according to the fourth embodiment of the present invention.

Figure 16 is an exploded perspective view of the micro linear slide rail omitting the track according to the fifth embodiment of the present invention.

Figure 17 is a perspective view of a micro linear slide rail omitting the track according to the fifth embodiment of the present invention.

Figure 18 is a perspective view of the retainer provided by the micro linear slide rail according to the sixth embodiment of the present invention.

Fig. 19 is a perspective view of a miniature linear slide rail omitting the track according to the sixth embodiment of the present invention.

Figure 20 is an exploded perspective view of the micro linear slide rail omitting the track according to the seventh embodiment of the present invention.

Figure 21 is a perspective view of the micro linear slide rail omitting the track according to the seventh embodiment of the present invention.

Figure 22 is a perspective view of a miniature linear slide rail according to the eighth embodiment of the present invention.

Figure 23 is an exploded perspective view of the miniature linear slide rail omitting the track according to the eighth embodiment of the present invention.

Figure 24 is a cross-sectional view along line 24-24 of Figure 22.

Fig. 25 is a cross-sectional view along line 25-25 of Fig. 22.

The applicant would like to first explain that throughout the specification, including the embodiments introduced below and the claims within the scope of the patent application, all terms related to directionality are represented by those in the drawings. direction as the base. Secondly, in the embodiments and drawings to be introduced below, the same component numbers represent the same or similar components or structural features.

Please refer to Figure 1 first. The Miniature Linear Guide 10 (Miniature Linear Guide) of the first embodiment of the present invention is suitable for small precision equipment or situations with limited space. In terms of size, the height is about 1cm. As for the The width is about 2cm. Please continue to refer to FIGS. 1 and 2 . The miniature linear slide rail 10 according to the first embodiment of the present invention includes a track 20 , a slide block 30 , two circulating accessories 40 , a plurality of balls 50 , and a retainer 60 .

The left and right sides of the track 20 respectively have a first rolling groove 22 and a retaining groove 24 adjacent to the first rolling groove 22.

The slider 30 has a belly 31 and two side portions 32 connected to the belly 31 oppositely. The inner surface of each side portion 32 has a second rolling groove 33. The slider 30 is slidably assembled on the track 20 so that The second rolling grooves 33 of the slider 30 correspond to the first rolling grooves 22 of the track 20 in a one-to-one manner, whereby the second rolling grooves 33 of the slider 30 and the third rolling grooves 33 of the track 20 A load channel 52 is respectively formed between the rolling grooves 22 . In addition, as shown in FIGS. 2 and 3 , each side portion 32 has a non-load channel 34 , and the non-load channel 34 penetrates the front and rear end surfaces of the side portion 32 .

The circulation accessories 40 are provided on the front and rear end surfaces of the slider 30 . The left and right ends of each circulation fitting 40 respectively have a turning protrusion 41 and a return groove 42 adjacent to the turning protrusion 41. Each turning protrusion 41 has a positioning end face 411, and the two ends of each return groove 42 are connected to the load channel 52. One end and one end of the non-load channel 34, so that the load channel 52, the non-load channel 34 and the front and rear return grooves 42 together form a circulation channel 54 for the balls 50 to run (as shown in Figure 3). In addition, as shown in FIG. 6 , each circulation fitting 40 further has a receiving groove 43 adjacent to the steering convex portions 41 .

The retainer 60 is an integrated structure made of metal material by stamping processing. As shown in FIG. 2 , the retainer 60 has a plate portion 61 , four positioning portions 62 and two holding portions 63 . The plate portion 61 is rectangular, and the width W1 of the plate portion 61 is smaller than the distance between the turning protrusions 41 . The distance D (as shown in FIGS. 7 and 8 ), the positioning parts 62 are connected to the four corners of the plate part 61 on the one hand, and the two ends of the holding parts 63 on the other hand. Each positioning part 62 is against On the positioning end surface 411 of each steering convex portion 41 of each circulation accessory. During assembly, as shown in FIGS. 5 and 6 , since the width W1 of the plate portion 61 is smaller than the distance D between the turning protrusions 41 , the retainer 60 can be directly pressed into the slider 30 along a single direction. After the assembly is completed, as shown in FIGS. 3 and 4 , the plate portion 61 of the retainer 60 abuts the belly 31 of the slider 30 , and the positioning portions 62 of the retainer 63 abut the circulation accessories 40 The turning protrusions 41 are located in the receiving grooves 43 of the circulating accessories 40, so that the retainer 60 is positioned, and the retaining parts 63 of the retainer 60 are located in the retaining grooves 24 of the track 20 and abut against each other. For the balls 50 passing through the load channel 52 , the retainer 60 provides a retaining effect for the balls 50 passing through the load channel 52 .

On the other hand, as shown in FIGS. 8 and 9 , the cross-sectional shape of the holding portion 63 is rectangular, and the width-to-thickness ratio of the holding portion 63 is not less than 1.5. This ensures that the holding portion 63 has sufficient structural strength and is not easily deformed to provide Good holding effect; as shown in Figures 8 and 10, the cross-sectional shape of each positioning portion 62 is also rectangular, and the length-to-thickness ratio of each positioning portion 62 is not less than 1.5, which ensures that each positioning portion 62 has sufficient Structural strength and not easy to deform to provide good positioning effect.

In order to further improve the structural stability of the retainer 60, the slider 30, the circulation accessory 40 and the retainer 60 are positioned with each other in different structural changes in the following embodiments.

As shown in Figure 11, in the second embodiment of the present invention, the bottom surface of the belly 31 of the slider 30 has a rectangular recess 35, and the retainer 60 integrally projects a rectangular protrusion upward from the plate portion 61. portion 64. When the retainer 60 is pressed into the slider 30, the convex portion 64 of the retainer 60 is embedded into the concave portion 35 of the slider 30 at the same time, as shown in Figure 12. This can improve the positioning effect between the two.

As shown in Figure 13, in the third embodiment of the present invention, each circulation accessory 40 further has two positioning blocks 44. Each positioning block 44 protrudes from the steering convex portion 41 into the accommodating groove 43 along the extension direction of the track 20. After the retainer 60 is assembled, the positioning portions 62 of the retainer 60 are engaged with the positioning blocks 44 of the circulation accessories 40 in a one-to-one manner, which can improve the positioning effect between the two.

As shown in Figure 14, in the fourth embodiment of the present invention, the retainer 60 further has four wing portions 65. Each wing portion 65 extends horizontally from the positioning portion 62 in a direction away from the plate portion 61. When the retainer 60 is completed After assembly, as shown in FIG. 15 , the wings 65 of the retainer 60 abut against the outer end surfaces 45 of the circulation accessories 40 , causing the retainer 60 to produce a clamping effect. As shown in Figures 16 and 17, in the fifth embodiment of the present invention, two positioning posts 46 are further provided on the outer end surface 45 of each circulation accessory 40, and each wing 65 of the retainer has a positioning hole 66. The device is engaged with the positioning posts 46 of the circulation accessories 40 in a one-to-one manner through the positioning holes 66 of each wing 65 to improve the positioning effect between the two.

However, the number and position of the wing portions 65 can also be varied. As shown in Figure 18, in the sixth embodiment of the present invention, the retainer 60 further has two wing portions 65. The wing portions 65 are formed from two ends of the retaining portion 63. Extending upward, when the retainer 60 is assembled, as shown in Figure 19, the two wings 65 of the retainer 60 respectively contact the outer end surfaces 45 of each circulation accessory 40, which also allows the retainer 60 to clamp. lasting effect. In addition, as shown in Fig. 20 and Fig. 21, in the seventh embodiment of the present invention In this example, the outer end surface 45 of each circulation fitting 40 has a positioning post 46, and each wing portion 65 of the retainer 60 has a positioning hole 66. The retainer 60 is connected to the circulation accessory 40 through the positioning holes 66 of the wing portions 65. positioning pillar 46 to improve the positioning effect between the two.

On the other hand, the number of circulation accessories is two in the above embodiments. In fact, the number of circulation accessories can be only one according to different configurations of slide rails. Further, please refer to Figure 22 and Figure 23 , the miniature linear slide rail 10' of the eighth embodiment of the present invention includes a track 20, a slider 70, a circulation accessory 80, a plurality of balls 50, and a retainer 60.

The two side surfaces of the track 20 respectively have a first rolling groove 22 and a retaining groove 24 adjacent to the first rolling groove 22.

Each side portion 72 of the slider 70 has two mutually parallel second rolling grooves 73 and two opposite first return grooves 74 . The first return grooves 74 are adjacent to both ends of the second rolling groove 73 . The slider 70 is assembled on the track 20 so that a load channel 52 is formed between one of the second rolling grooves 73 on each side 72 of the slider 70 and the first rolling groove 22 of the track 20 (as shown in Figure 24). .

The circulation accessory 80 has two opposite socket grooves 81. A third rolling groove 82 and two opposite second return grooves 83 are provided around each socket groove 81. The second return grooves 83 are connected to the third rolling groove 82. Two ends. Each side portion 72 of the slider 70 is assembled in the socket groove 81 of the circulation accessory 80 so that there is a gap between the other second rolling groove 73 of each side portion 72 of the slider 70 and the third rolling groove 82 of the circulation accessory 80 A non-load channel 56 is formed, and the first return grooves 74 on each side 72 of the slider 70 correspond to the second return grooves 83 of the circulation fitting 80 . Thereby, as shown in FIG. 25 , the load channel 52 , the non-load channel 56 , the first return grooves 74 and the second return grooves 83 together form a circulation channel 54 for the balls 50 to run. In addition, as shown in Figure 23, the loop The ring fitting 80 further has four turning protrusions 84 , each of which is adjacent to a second return groove 83 .

The retainer 60 is directly pressed into the slider 30 in one direction to complete the assembly. After the assembly is completed, as shown in Figures 24 and 25, the plate portion 61 of the retainer 60 is adjacent to the belly 71 of the slider 70, and the retainer The positioning parts 62 of the 60 contact the turning convex parts 84 of the circulation fitting 80 to position the retainer 60, and the retaining parts 63 of the retainer 60 are located in the retaining grooves 24 of the track 20 and abut against the passage The balls 50 in the load channel 52 enable the retainer 60 to provide a retaining effect to the balls 50 passing through the load channel 52 .

To sum up, the retainer 60 provided by the present invention is pressed in in a single direction to complete the assembly with the slider 30. It is relatively easy to assemble, reduces the assembly process, and can be matched with different structural designs. To improve the positioning effect, it can effectively improve assembly efficiency and reduce assembly costs, thereby achieving the purpose of automated assembly.

20: Orbit

22: First rolling groove

24:Retention slot

30:Slider

31:Abdomen

32: Side

33: Second rolling groove

34: Non-load channel

40: Circulation accessories

41: Steering convex part

42:Return tank

43: Container

50: Ball

60: retainer

61: Board

62: Positioning Department

63:Maintenance Department

Claims (10)

A miniature linear slide rail, including: a track; a slide block slidably disposed on the track; the slide block has an abdomen and two side parts, and the side parts connect two opposite sides of the abdomen; at least one A circulation accessory is slidably disposed on the track and connected to the slider, so that a circulation channel is formed between the circulation accessory, the track and each side of the slider, and the circulation accessory has a plurality of turning convex portions; A plurality of balls are arranged in the circulation channels; and a retainer has a plate part, a plurality of positioning parts and two holding parts, and the two ends of each holding part are respectively connected to the plate part by a positioning part, the The plate portion of the retainer is adjacent to the belly of the slider, and the positioning portions of the retaining portion are abutted against the turning convex portions of the circulating accessories, and each retaining portion of the retainer is abutted against The balls, wherein the width of the plate portion of the retainer is smaller than the distance between the turning convex portions of the circulation accessories; each turning convex portion of the at least one circulation accessory has a positioning end surface; the retainer's Each positioning portion is respectively pressed against the positioning end surface of each turning convex portion of the at least one circulation accessory. The miniature linear slide rail as claimed in claim 1, wherein two sides of the rail have a first rolling groove and a retaining groove adjacent to the first rolling groove, and each side of the slider has a second rolling groove. The second rolling grooves of the slider correspond to the first rolling grooves of the track one-to-one, so that the second rolling grooves of the slider correspond to the first rolling grooves of the track. A load channel is formed respectively, and each side of the slider has a non-load channel. channel, each of the non-load channels runs through two opposite end surfaces of the side; the number of the circulation accessories is two, each of the circulation accessories is provided on the two opposite end surfaces of the slider and has two turning convex parts and two return grooves, each of which The return groove is adjacent to one of the turning convex portions, and two ends of each return groove are connected to one end of the load channel and one end of the non-load channel, so that one load channel, one non-load channel and two return grooves together form a The circulation channel; each retaining portion of the retainer is located in the retaining groove of the track and abuts against the balls passing through a load channel. The miniature linear slide rail as claimed in claim 1, wherein two sides of the rail have a first rolling groove and a retaining groove adjacent to the first rolling groove, and each side of the slider has two mutually parallel The second rolling groove and the two opposite first return grooves, a load channel is respectively formed between the second rolling groove on each side of the slider and the first rolling groove of the track; the circulation accessory The number is one, and the circulation accessory further has two opposite socket grooves and four turning convex portions. A third rolling groove and two opposite second return grooves are arranged around each socket groove. The second return grooves Connecting the two ends of the third rolling groove, one of the second rolling grooves on each side of the slider corresponds to one of the first rolling grooves of the slide rail, and the other of each side of the slider The second rolling groove corresponds to the third rolling groove of the circulation accessory, and the first return grooves on each side of the slider correspond to the second return grooves of the circulation accessory, so that the first return grooves The rolling groove, the second rolling grooves, the third rolling groove, the first return grooves and the second return grooves together form a circulation channel; each second return groove is adjacent to a turning convex portion, And each second return groove is connected to one of the load channels, and each holding part of the retainer is located in the holding groove of the track and contacts the balls passing through one of the load channels. The miniature linear slide rail as claimed in claim 1, wherein the bottom surface of the belly of the slider has a recessed portion, the retainer integrally forms a convex portion from the plate portion, and the convex portion is embedded in the recessed portion. The miniature linear slide rail as claimed in claim 1, wherein the circulation accessory further has a plurality of positioning blocks, each positioning block protrudes from a turning protrusion along the extension direction of the track, and each of the positioning blocks of the retainer The positioning part is engaged with the positioning block of one of the circulation accessories. The miniature linear slide as claimed in claim 1, wherein the holder further has a plurality of wings, each of which extends from one of the positioning parts in a direction away from the plate part and abuts against the circulation accessory. One outer end face. The miniature linear slide as described in claim 6, wherein the outer end surface of the circulation accessory has a plurality of positioning posts, and each wing of the retainer has a positioning hole, and the positioning holes are snap-fitted to the positioning posts. column. The miniature linear slide as claimed in claim 1, wherein the holder further has a plurality of wings, each of which extends upward from one end of the holding part and abuts against an outer end surface of the circulation accessory. . The miniature linear slide as claimed in claim 1, wherein the cross-sectional shape of each holding portion is rectangular, and the width-to-thickness ratio of each holding portion is not less than 1.5. The miniature linear slide rail according to claim 1, wherein the cross-sectional shape of each positioning portion is rectangular, and the length-to-thickness ratio of each positioning portion is not less than 1.5.

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