A press-fitting tooling, method and air spring for an air spring support positioning ring

Abstract

The present invention provides a press-fitting tooling, a method and an air spring for an air spring support positioning ring. The press-fitting tooling includes an upper die and a lower die. Among them, a first die cavity is arranged inside the upper die, and a first relief groove is arranged at the end of the first die cavity. The lower die includes a lower die base, an expansion bladder and an expansion die. A second die cavity is arranged inside the lower die base, and a second relief groove is arranged at the end of the second die cavity. The first relief groove and the second relief groove are buckled with each other, and a positioning step is arranged inside the second die cavity. The expansion bladder is arranged inside the second die cavity. The expansion die is arranged inside the second die cavity and is formed by enclosing a plurality of expansion petals. A protrusion is arranged on the circumference of the expansion petal, and the inner surface of the expansion petal is a conical surface. When an external force is applied to the conical surface, the expansion petal can move outward. The present invention is used to solve the problem of difficult assembly of the support positioning ring caused by the existing process.

Description

Technical Field

[0001] The present invention relates to the field of air springs, and particularly to a press-fitting tooling and method for an air spring support positioning ring and an air spring. Background Art

[0002] An air spring is filled with compressed air in a sealed container, and its elastic effect is realized by the compressibility of the gas. Air springs are widely used in the automotive field to achieve shock absorption effects. An airbag and a guide sleeve sleeved outside the airbag are indispensable components of an air spring. Among them, the airbag is fixedly connected to the guide sleeve through a support positioning ring. However, in the process of realizing the press-fitting of the support positioning ring by using the existing process, the following problems exist:

[0003] First of all, under the existing process, the support positioning ring hardly deforms, and the fixation of the airbag, the support positioning ring and the guide sleeve is achieved by the deformation of the guide sleeve. The support positioning ring needs to be installed into the airbag when the airbag is in a free state. However, when the outer diameter of the support positioning ring is quite different from the inner diameter of the airbag in the free state (for example, when the outer diameter of the support positioning ring is 5 - 30 mm larger than the inner diameter of the airbag in the free state), the assembly of the support positioning ring will become very difficult. In addition, the anti-corrosion coating on the outer surface of the guide sleeve is likely to peel off during deformation.

[0004] Secondly, during use, the end of the guide sleeve is likely to damage the airbag, reducing the service life of the air spring. Summary of the Invention

[0005] In view of the above disadvantages of the prior art, the present invention provides a press-fitting tooling and method for an air spring support positioning ring and an air spring to improve the problem of difficult assembly of the support positioning ring caused by the existing process.

[0006] To achieve the above object and other related objects, the present invention provides a press-fitting tooling for an air spring support positioning ring, including: an upper die and a lower die; wherein, a first die cavity is arranged inside the upper die, and a first relief groove is arranged at the end of the first die cavity; the lower die includes: a lower die base, an airbag expansion part and an expansion die; a second die cavity is arranged inside the lower die base, and a second relief groove is arranged at the end of the second die cavity. The first relief groove and the second relief groove are buckled together, and a positioning step is arranged inside the second die cavity; the airbag expansion part is arranged inside the second die cavity; the expansion die is arranged inside the second die cavity and is formed by enclosing a plurality of expansion petals. Protrusions are arranged on the circumference of the expansion petals, and the inner surface of the expansion petals is a conical surface. When an external force is applied to the conical surface, the expansion petals can move outwards.

[0007] In an embodiment of the present invention, it further includes a punch, and the end of the punch is a conical surface. The conical surface of the punch matches the conical surface of the expansion petals. When the punch contacts the expansion petals and undergoes relative movement, the punch pushes a plurality of expansion petals to move outward synchronously, causing the support positioning ring to deform and expand outward and squeezing the guide sleeve into the first relief groove and the second relief groove.

[0008] In an embodiment of the present invention, the expansion bladder includes: a mounting seat and a first airbag. The mounting seat is mounted on the lower die base, and the first airbag is mounted on the base. A serrated groove is provided at the connection between the mounting seat and the first airbag, and the first airbag is hermetically fixed to the serrated groove of the mounting seat through a confinement ring. The function of the serrated groove is both anti-slip and to increase the sealing performance.

[0009] In an embodiment of the present invention, a vent hole is provided on the lower die base, and the vent hole is provided at the bottom of the lower die base. A gas passage is provided on the mounting seat. One end of the gas passage communicates with the inner cavity of the first airbag, and the other end communicates with the outside of the first airbag. The vent hole is connected to the chamber of the first airbag through the gas passage, and a sealing ring is provided at the connection between the vent hole and the gas passage to prevent gas leakage during the gas flow process. Therefore, the first airbag can be inflated externally. During press-fitting, the first airbag needs to be in a full state, that is, filled with gas and the air pressure is within a set range. The function of the first airbag is to fix the second airbag in the die cavity (the first die cavity and the second die cavity) to prevent the second airbag from moving during the stamping of the support positioning ring.

[0010] In an embodiment of the present invention, the inner surface of the first relief groove is a first smooth curved surface, and the inner surface of the second relief groove is a second smooth curved surface. The first smooth curved surface and the second smooth curved surface are smoothly connected. Therefore, when the guide sleeve is squeezed into the first relief groove and the second relief groove, it will not cause damage to the outer surface, and can effectively improve the problem of the anti-corrosion coating peeling off.

[0011] In an embodiment of the present invention, the two end faces of the protrusion are conical surfaces inclined towards the axis. Thus, it is ensured that during press-fitting, the guide sleeve can be squeezed into the first relief groove and the second relief groove.

[0012] In an embodiment of the present invention, a first groove and a second groove are provided on the expansion petal, and the protrusion is located between the first groove and the second groove. The first groove and the second groove are used to install a confinement ring. The confinement ring can be an O-shaped rubber ring.

[0013] The present invention also provides a press-fitting method, including the steps:

[0014] Place the support positioning ring in the inner cavity of the second airbag, and adjust the support positioning ring until it is coaxial with the second airbag and the support positioning ring is located at the positioning position of the second airbag;

[0015] Place the guide sleeve in the press-fitting tooling, and the end of the guide sleeve is located on the positioning step;

[0016] Place the second airbag in the press-fitting tooling. The second airbag is located inside the guide sleeve, and the bulging part is located inside the second airbag;

[0017] Inflate the first airbag until the second airbag is fixed between the first airbag and the inner wall of the second die cavity, and maintain the pressure of the first airbag;

[0018] Use a punch to punch the bulging die, so that the bulging petals move outward to squeeze the support positioning ring to expand outward, thereby squeezing the guide sleeve into the first relief groove and the second relief groove.

[0019] The present invention also provides an air spring. A support positioning ring is arranged in the air spring. The support positioning ring presses the second airbag on the guide sleeve by the method. A ring-shaped rib is bulged outward at the position of the guide sleeve corresponding to the support positioning ring.

[0020] In an embodiment of the present invention, flanges are respectively arranged at both ends of the guide sleeve. The free ends of the flanges are turned outward towards the outside of the guide sleeve, and the other ends of the flanges are turned inward towards the inside of the guide sleeve. The flanges are smoothly transitioned from the free ends to the other ends.

[0021] For the press-fitting tooling of the support positioning ring of the air spring of the present invention, when several bulging petals are subjected to an external force, they expand outward, causing the support positioning ring to expand outward and deform, and squeezing the guide sleeve into the first relief groove and the second relief groove to complete the press-fitting. Through this tooling, the support positioning ring can be deformed by expanding and pressing from the inside to the outside. Therefore, during the press-fitting process, a support positioning ring with an outer diameter slightly larger than the inner diameter of the second airbag can be selected, thereby reducing the assembly difficulty of the support positioning ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is the assembly drawing of the press-fitting tooling of the present invention;

[0024] Figure 2 This is the assembly drawing of the lower die base and the first airbag of the present invention;

[0025] Figure 3 This is the exploded view of the lower die base and the first airbag of the present invention;

[0026] Figure 4 This is the schematic structural diagram of the first airbag of the present invention when not inflated;

[0027] Figure 5 This is the schematic structural diagram of the first airbag of the present invention after inflation;

[0028] Figure 6 This is the top view of the die expansion of the present invention;

[0029] Figure 7 This is the bottom view of the die expansion of the present invention;

[0030] Figure 8 This is the cross-sectional view of the die expansion of the present invention;

[0031] Figure 9 This is the assembly schematic diagram of the die expansion and the restraint ring of the present invention;

[0032] Figure 10 This is the schematic structural diagram of the die expansion after expansion of the present invention;

[0033] Figure 11 This is the schematic structural diagram of putting the support positioning ring into the second airbag of the present invention;

[0034] Figure 12 This is the schematic mating structure diagram of the expansion claws and the support positioning ring when the expansion claws are retracted;

[0035] Figure 13 This is the schematic structural diagram of adjusting the support positioning ring after the expansion claws are expanded;

[0036] Figure 14 This is the flowchart of the pressing method of the present invention;

[0037] Figure 15 This is the schematic structural diagram of the air spring of the present invention;

[0038] Figure 16 For the present invention Figure 15 The enlarged view of region I;

[0039] Figure 17 For the present invention Figure 15 The enlarged view of region II.

[0040] Element number description

[0041] 100. Upper die; 110. First die cavity; 120. First relief groove; 200. Lower die; 210. Lower die base; 211. Second die cavity; 212. Second relief groove; 213. Positioning step; 214. Vent hole; 220. Bladder; 221. Mounting seat; 222. First airbag; 223. Gas passage; 230. Die expansion; 2310. Expanding flap; 2311. Projection; 2312. Tapered surface; 2313. First groove; 2314. Second groove; 2320. Binding ring; 300. Guide sleeve; 310. Ring-shaped rib; 320. Flanging; 321. Free end; 400. Second airbag; 500. Support positioning ring; 600. Elastic expansion claw; 610. Slide sleeve; 700. Swing fixing seat; 800. Lifting piston; 900. Punch. Detailed implementation manners

[0042] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. It should also be understood that the terms used in the embodiments of the present invention are for describing specific specific implementation manners, rather than for limiting the protection scope of the present invention. The test methods without specific conditions noted in the following embodiments are usually carried out under conventional conditions or according to the conditions recommended by each manufacturer.

[0043] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of clear narration, rather than for limiting the scope of implementation of the present invention. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope of implementation of the present invention.

[0044] Please refer to Figure 1The present invention provides a press-fitting tool for an air spring support positioning ring, comprising: an upper die 100 and a lower die 200, wherein the upper die 100 and the lower die 200 are detachably connected. Among them, the upper mold 100 is provided with a first mold cavity 110 inside, and a first give-way groove 120 is provided at the end of the first mold cavity 110; the lower mold 200 includes: a lower mold base 210, an expansion bladder 220 and an expansion mold 230; the lower mold base 210 is provided with a second mold cavity 211 inside, the first mold cavity 110 is connected with the second mold cavity 211, and a second give-way groove 212 is provided at the end of the second mold cavity 211, the first give-way groove 120 and the second give-way groove 212 are buckled to form an annular give-way groove, and a positioning step 213 is provided inside the second mold cavity 211; the expansion bladder 220 is arranged in the second mold cavity 211, and the expansion bladder 220 can expand and open in the inflated state and fix the second airbag 400 in the second mold cavity 211; the expansion mold 230 is arranged in the second mold cavity 211 and is located above the expansion bladder 220, and the expansion mold 230 is coaxial with the second mold cavity 211. The expansion mold 230 is formed by a plurality of expansion petals 2310, and a protrusion 2311 is provided on the circumference of the expansion petal 2310. The inner surface of the expansion petal 2310 is a 1 / n cone surface 2312, wherein n is the number of the expansion petals 2310, and the value range is a positive integer greater than or equal to 2. In a free state (i.e., a naturally placed state), the 1 / n cone surfaces 1212 of the n expansion petals 2310 are connected to each other to form a complete cone surface. When an external force is applied to the 1 / n cone surface 2312, the expansion petal 2310 can move outward, so that the protrusion 2311 squeezes the support positioning ring 500 and the guide sleeve 300, so that the guide sleeve 300 bulges outward to form an annular rib ring 310.

[0045] See also Figure 1 In one embodiment of the present invention, a punch 900 is further included, and the end of the punch 900 is a conical surface. The punch 900 is installed on the stamping equipment, and the conical surface of the punch 900 matches the conical surface 2312 of the expansion petal 2310. The stamping equipment drives the punch 900 to move downward. When the punch 900 contacts the expansion petal 2310 and moves further downward, the punch 900 pushes several expansion petals 2310 to move outward synchronously, so that the support and positioning ring 500 is deformed and expanded outward and squeezes the guide sleeve 300 into the first clearance groove 120 and the second clearance groove 212.

[0046] See also Figure 1, in an embodiment of the present invention, the first relief groove 120 and the second relief groove 212 are engaged to form a relief ring. The inner surface of the first relief groove 120 is a first smooth surface, the inner surface of the second relief groove 212 is a second smooth surface, and the first smooth surface is smoothly connected to the second smooth surface to form an annular groove. Therefore, the inner surface of the relief ring is smooth, and when the guide sleeve 300 is pressed into the relief ring, the outer surface will not be damaged, effectively improving the problem of anti-corrosion coating detachment.

[0047] Please refer to Figures 2 to 3 , in an embodiment of the present invention, the expansion bladder 220 is detachably mounted on the lower die base 210 and is located in the second die cavity 211. The detachable mounting method can be bolt mounting. The expansion bladder 220 includes: a mounting seat 221 and a first airbag 222. The mounting seat 221 is mounted on the lower die base 210, and the first airbag 222 is mounted on the base. A serrated groove is provided at the connection between the mounting seat 221 and the first airbag 222, and the first airbag 222 is hermetically fixed to the serrated groove of the mounting seat 221 through a confinement ring. The function of the serrated groove is both anti-slip and to increase the sealing performance.

[0048] Please refer to Figures 2 to 5 , in an embodiment of the present invention, the lower die base 210 is provided with a vent hole 214. The vent hole 214 is provided at the bottom of the lower die base 210. The mounting seat 221 is provided with a gas passage 223. One end of the gas passage 223 communicates with the inner cavity of the first airbag 222, and the other end communicates with the outside of the first airbag 222. The vent hole 214 is connected to the chamber of the first airbag 222 through the gas passage 223. A sealing ring is provided at the connection between the vent hole 214 and the gas passage 223 to prevent gas leakage during the gas flow. Therefore, the first airbag 222 can be inflated externally. During press-fitting, the first airbag 222 needs to be in a full state, that is, filled with gas and the air pressure is within a set range. The function of the first airbag 222 is to fix the second airbag 400 in the die cavity (the first die cavity 110 and the second die cavity 211) to prevent the second airbag 400 from moving during the stamping of the support positioning ring 500.

[0049] Please refer to Figures 6 to 8 , in an embodiment of the present invention, the more the number of expansion petals 2310, the better the press-fitting effect of the support positioning ring 500, but the higher the tooling cost. In a preferred embodiment of the present invention, the expansion die 230 includes eight expansion petals 2310. The eight expansion petals 2310 are arranged annularly to enclose the expansion die 230. The number of expansion petals 2310 is 8, taking into account both the press-fitting effect and the tooling cost.

[0050] Please refer to Figure 8, in an embodiment of the present invention, the two end faces of the protrusion 2311 are conical surfaces inclined towards the axis. The outer side surface of the protrusion 2311 can be a cylindrical surface. Or the outer side surface of the protrusion 2311 can be an annular curved surface matching the annular relief ring. Thus, when press-fitting, the guide sleeve 300 can be extruded into the first relief groove 120 and the second relief groove 212.

[0051] Please refer to Figures 9 to 10 , in an embodiment of the present invention, the expansion petals 2310 are provided with a first groove 2313 and a second groove 2314, and the protrusion 2311 is located between the first groove 2313 and the second groove 2314. The first groove 2313 and the second groove 2314 are used to install the elastic restraint ring 2320. When the punch 900 performs stamping, several expansion petals 2310 synchronously move radially outwards along their respective corresponding directions. After the press-fitting is completed, the punch 900 is reset. Under the action of the restraint ring 2320, several expansion petals 2310 synchronously contract and enclose together again. The restraint ring 2320 can be an O-shaped rubber ring.

[0052] The present invention also provides a press-fitting method, including the steps:

[0053] Please refer to Figures 11 to 13 , the staff places the support positioning ring 500 at a reasonable position inside the second airbag 400, and adjusts the support positioning ring 500 by using the elastic expansion claws 600 until the support positioning ring is coaxial with the second airbag 400, and the support positioning ring 500 is located at the positioning position of the second airbag 400. The elastic expansion claws 600 are installed on the corresponding up-and-down movement mechanism, and its working principle is: the elastic expansion claws 600 can be dragged up or down through this mechanism. The middle part of the elastic expansion claws 600 bulges, and a sliding sleeve 610 is sleeved on the upper end of the bulging part. The inner surface of the sliding sleeve 610 is a conical surface, with the large diameter of the conical surface facing downwards and the small diameter facing upwards. Manually pulling down the sliding sleeve 610 can contract the expansion claws, and pushing up the sliding sleeve 610 can release the expansion claws. In the free state, the expansion claws are in an open state. Under the control of the servo mechanism, by manually controlling the up and down of the sliding sleeve 610, the support positioning ring pre-loaded into the airbag can be pushed or pulled to the required positioning height. And since the end of the spring expansion claws is provided with a step, and the horizontal part of the step is perpendicular to the axis of the second airbag 400, the support positioning ring 500 can be guaranteed to be perpendicular to the second airbag 400 axially through this step.

[0054] Please refer to Figure 5 and Figure 14, place the guide sleeve 300 into the press-fitting tooling, with the end of the guide sleeve 300 located on the positioning step 213; place the second airbag 400 into the press-fitting tooling, with the end of the second airbag 400 located at the bottom of the second die cavity 211. The second airbag 400 is located inside the guide sleeve 300, and a part of the bladder 220 is located inside the second airbag 400. Align the air source with the vent hole 214 to inflate the first airbag 222 until the second airbag 400 is fixed between the first airbag 222 and the inner wall of the second die cavity 211, and maintain the pressure of the first airbag 222. When performing this step, it is necessary to confirm the tightness and connectivity of the vent hole 214 and the gas passage 223 to ensure the smoothness of the inflation process. The pressure maintenance means that the air pressure inside the first airbag 222 is maintained within a set range, and this set range is a reasonable range set by the staff according to the specific implementation environment. The pressure maintenance can include, but is not limited to, the following methods: blocking the vent hole 214 with a rubber plug or blocking the vent hole 214 with the air source.

[0055] Please refer to Figure 1 , start the stamping equipment. The stamping equipment drives the punch 900 to stamp the expanding die 230, causing the expanding petals 2310 to move outward and squeeze the support positioning ring 500 to expand outward, thereby squeezing the guide sleeve 300 into the first relief groove 120 and the second relief groove 212. In this step, before stamping, it is necessary to detect the punch 900 and the stamping equipment, and determine whether the expanding die 230 is assembled properly. In this step, when the guide sleeve 300 is squeezed into the retaining ring, the staff can choose whether to maintain the extrusion according to the actual conditions, and the holding time (just keep an appropriate time, such as 1 - 5S), etc.

[0056] The stamping equipment resets to complete the press-fitting.

[0057] Please refer to Figure 15 , the present invention also provides an air spring, including a second airbag 400. One end of the second airbag 400 is sealed and installed on the swing fixed seat 700, and the other end of the second airbag 400 is sealed and installed on the lifting piston. A guide sleeve is arranged outside the second airbag 400. A support positioning ring 500 is arranged inside the second airbag 400. The second airbag 400 is press-fitted onto the guide sleeve 300 by the method, and a ring-shaped rib 310 bulges outward at the position of the guide sleeve 300 corresponding to the support positioning ring 500.

[0058] Please refer to Figures 16 to 17, in an embodiment of the present invention, flanges 320 are respectively provided at two end portions of the guide sleeve 300. The free end 321 of the flange 320 turns outward towards the outside of the guide sleeve 300, and the other end of the flange 320 turns inward towards the inside of the guide sleeve 300. The flange 320 smoothly transitions from the free end 321 to the other end. The outward turning of the free end 321 of the flange 320 can effectively prevent the guide sleeve 300 from damaging the second airbag 400, and the inward turning of the other end ensures that the guide sleeve 300 can be smoothly inserted into the second die cavity 211.

[0059] For the press-fitting tooling of the air spring support positioning ring 500 of the present invention, when a plurality of expansion flaps 2310 are subjected to an external force, they expand outward, causing the support positioning ring 500 to expand and deform outward, and squeezing the guide sleeve 300 into the first relief groove 120 and the second relief groove 212 to complete the press-fitting. Through this tooling, the support positioning ring 500 can be deformed by expanding and pressing from the inside out. Therefore, during the press-fitting process, a support positioning ring 500 with an outer diameter slightly larger than the inner diameter of the second airbag 400 can be selected (for example, the outer diameter of the support positioning ring 500 is 1-4 mm larger than the inner diameter of the second airbag 400 at the corresponding position in the free state), thereby reducing the assembly difficulty of the support positioning ring. Therefore, the present invention effectively overcomes some practical problems in the prior art and thus has high utilization value and practical significance.

[0060] The above embodiments merely illustrate the principles and effects of the present invention, rather than limiting the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A pressing method for a pressing tool using an air spring to support a positioning ring, characterized in that The press-fitting tooling for the air spring support positioning ring includes: An upper die, inside which there is a first die cavity, and a first relief groove is provided at the end of the first die cavity; A lower die; The lower die includes: A lower die base, inside which there is a second die cavity, and a second relief groove is provided at the end of the second die cavity. The first relief groove and the second relief groove are engaged with each other, and a positioning step is provided inside the second die cavity; An expansion bladder, arranged inside the second die cavity; the expansion bladder includes a mounting seat and a first airbag. The mounting seat is mounted on the lower die base, and the first airbag is mounted on the mounting seat; An expansion die, arranged inside the second die cavity, formed by enclosing a plurality of expansion petals. Protrusions are provided on the circumference of the expansion petals, and the inner surface of the expansion petals is a conical surface. When an external force is applied to the conical surface, the expansion petals can move outward; The press-fitting method includes the following steps: Place the support positioning ring inside the inner cavity of the second airbag, and adjust the support positioning ring until the support positioning ring is coaxial with the second airbag and the support positioning ring is located at the positioning position of the second airbag; Place the guide sleeve inside the press-fitting tooling, and the end of the guide sleeve is located on the positioning step; Place the second airbag inside the press-fitting tooling. The second airbag is located inside the guide sleeve, and a part of the expansion bladder is located inside the second airbag; Inflate the first airbag until the second airbag is fixed between the first airbag and the inner wall of the second die cavity, and maintain the pressure of the first airbag; Use a punch to punch the expansion die, so that the expansion petals move outward to squeeze the support positioning ring to expand outward, thereby squeezing the guide sleeve into the first relief groove and the second relief groove.

2. The press-fitting method according to claim 1, wherein The press-fitting tooling for the air spring support positioning ring further includes a punch, and the end of the punch is a conical surface.

3. The press-fitting method according to claim 1, characterized in that, A vent hole is provided on the lower die base, and a gas passage is provided on the mounting seat. The vent hole is connected to the chamber of the first airbag through the gas passage.

4. The press-fitting method according to claim 1, wherein The inner surface of the first relief groove is a first smooth curved surface, and the inner surface of the second relief groove is a second smooth curved surface. The first smooth curved surface and the second smooth curved surface are smoothly connected.

5. The press-fitting method according to claim 1, wherein The two end faces of the protrusion are conical surfaces inclined towards the axis.

6. The press-fitting method according to claim 1, characterized in that, First grooves and second grooves are provided on the expansion petals, and the protrusions are located between the first grooves and the second grooves.

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