Electronic expansion valve

Abstract

The utility model discloses an electronic expansion valve which comprises a valve component and a coil component. The valve component comprises a valve body and a sleeve, and the valve body is connected with the sleeve; the valve body is provided with an annular part, and the annular part is arranged on the periphery of the sleeve in a sleeving mode. The coil component comprises a coil assembly and a sealing ring, at least part of the coil assembly is arranged on the periphery of the sleeve in a sleeving mode, and the sealing ring is fixedly arranged on the coil assembly, arranged on the periphery of the annular part in a sleeving mode and sealed between the annular part and the coil assembly.

Description

Technical Field

[0001] The present application relates to the field of refrigeration control technology, and in particular to an electronic expansion valve. Background Art

[0002] The electronic expansion valve in the related art includes a valve component and a coil component. When working, a pulse signal is applied to the coil component to drive the valve core assembly of the valve component to move, thereby adjusting the opening of the valve port to achieve control of the fluid flow.

[0003] In order to prevent moisture or other impurities in the external environment from entering the coil component through the assembly gap between the valve component and the coil component, thereby causing corrosion or failure of the coil component, a sealing ring is usually provided between the sleeve of the valve component and the coil component in the related art, and the sealing ring and the sleeve have an interference fit. However, in the process of sleeve-mounting the coil component on the outer periphery of the sleeve, the sealing ring is continuously squeezed by the sleeve and the coil component, and the air in the cavity between the coil component and the sleeve cannot be discharged, resulting in inconvenience in installation and affecting assembly efficiency. Utility Model Content

[0004] The embodiment of the present application provides an electronic expansion valve to solve the problem of inconvenient installation of a coil component and a sleeve in the related art.

[0005] The electronic expansion valve of the embodiment of the present application includes:

[0006] A valve component comprises a valve body and a sleeve, wherein the valve body and the sleeve are connected; the valve body has an annular portion, and the annular portion is sleeved on the outer circumference of the sleeve; and

[0007] The coil component comprises a coil assembly and a sealing ring, wherein at least a portion of the coil assembly is sleeved on the outer circumference of the sleeve, the sealing ring is fixedly arranged on the coil assembly, sleeved on the outer circumference of the annular portion, and sealed between the annular portion and the coil assembly.

[0008] According to some embodiments of the present application, the coil component further includes:

[0009] The limiting member is fixedly arranged on the coil assembly, and the sealing ring is limited between the limiting member and the coil assembly.

[0010] According to some embodiments of the present application, the coil assembly has a bottom surface, and the stopper is fixedly connected to the bottom surface; the coil assembly also has a sinking groove, and the sinking groove is recessed from the bottom surface along the axial direction of the electronic expansion valve toward the top of the coil assembly;

[0011] The sealing ring and the portion of the annular portion surrounded by the sealing ring are both located in the sinking groove, and the sealing ring abuts between the bottom surface of the sinking groove and the limiting member.

[0012] According to some embodiments of the present application, a first annular convex rib is provided on a surface of the sealing ring facing the limiting member, and the first annular convex rib abuts against the limiting member; and / or,

[0013] A second annular convex rib is provided on a surface of the sealing ring facing the coil assembly, and the second annular convex rib abuts against the coil assembly.

[0014] According to some embodiments of the present application, the inner circumferential surface of the sealing ring is interference fit with the outer circumferential surface of the annular portion.

[0015] According to some embodiments of the present application, the valve body includes:

[0016] a connecting sleeve connected to the sleeve; and

[0017] A connecting ring, a fixing sleeve is arranged on the outer periphery of the connecting sleeve, and the connecting ring has the annular portion.

[0018] According to some embodiments of the present application, the connecting sleeve is connected to the sleeve via a welding portion, and the connecting ring is covered on the welding portion.

[0019] According to some embodiments of the present application, the connecting ring and the connecting sleeve are interference fit.

[0020] According to some embodiments of the present application, the valve component also includes a valve seat having an installation cavity; at least a portion of the connecting sleeve and at least a portion of the connecting ring are located in the installation cavity, and the connecting ring is threadedly connected to the valve seat.

[0021] According to some embodiments of the present application, the cavity wall of the installation cavity has a second limiting portion;

[0022] A stopper portion abutting against the second limiting portion is disposed on the outer periphery of the connecting sleeve; the connecting ring abuts against the stopper portion and has a gap between the connecting ring and the second limiting portion.

[0023] According to some embodiments of the present application, the connecting ring further comprises a ring body located in the installation cavity, the ring body is fixedly sleeved on the outer peripheral surface of the connecting sleeve and is threadedly connected to the valve seat;

[0024] The annular portion is protrudingly arranged on a surface of the ring body facing the coil assembly, and a gap is provided between an inner peripheral surface of the annular portion and an outer peripheral surface of the sleeve.

[0025] According to some embodiments of the present application, the side of the annular portion facing away from the sleeve further has an annular groove, and at least a portion of the sealing ring is located in the annular groove.

[0026] One embodiment of the above application has at least the following advantages or beneficial effects:

[0027] The electronic expansion valve of the embodiment of the present application, on the one hand, can improve the sealing between the valve component and the coil component by arranging a sealing ring between the annular portion and the coil assembly, thereby preventing external water vapor or impurities from entering the coil assembly, thereby reducing the risk of corrosion of the coil assembly, thereby improving the working performance and service life of the coil assembly; on the other hand, the sealing ring is sleeved on the outer periphery of the annular portion without directly contacting the sleeve, so that in the process of sleeveing ​​the coil component on the outer periphery of the sleeve, the sealing ring will not generate contact friction with the sleeve, and there is also a gap between the coil component and the sleeve for air to be discharged, thereby improving the installation efficiency of the electronic expansion valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Shown is a three-dimensional schematic diagram of an electronic expansion valve according to an embodiment of the present application.

[0029] Figure 2 Shown is a cross-sectional view of an electronic expansion valve according to an embodiment of the present application.

[0030] Figure 3 It shows Figure 2 A local enlarged view of point X1 in the middle.

[0031] Figure 4 Shown is an exploded schematic view of the coil assembly.

[0032] Figure 5 Shown is a partial cross-sectional view of the sealing ring.

[0033] Figure 6 It shows Figure 2 A local enlarged view of the X2 point in the middle.

[0034] The reference numerals are described as follows:

[0035] 100. Valve parts

[0036] 110. Valve body

[0037] 111. Annular part

[0038] 111a, annular groove

[0039] 112. Connecting sleeve

[0040] 112a, first limiting portion

[0041] 112b, stopper

[0042] 113. Connecting ring

[0043] 113a, Ring body

[0044] 113b. Gap

[0045] 114. Welding Department

[0046] 120. Casing

[0047] 130. Valve core assembly

[0048] 140. Chamber

[0049] 150. Valve seat

[0050] 151. Installation cavity

[0051] 152. Second limiter

[0052] 153. Import

[0053] 154. Export

[0054] 200. Coil components

[0055] 210. Coil assembly

[0056] 211. Bottom surface

[0057] 212. Sink

[0058] 220. Sealing ring

[0059] 221. First annular rib

[0060] 222. Second annular rib

[0061] 230, limiter DETAILED DESCRIPTION

[0062] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted.

[0063] It is understood that the terms "including" and "having" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or components that are inherent to these processes, methods, products, or devices.

[0064] like Figures 1 to 3 As shown, the electronic expansion valve of the embodiment of the present application includes a valve component 100 and a coil component 200. The valve component 100 includes a valve body 110, a sleeve 120 and a valve core assembly 130. The valve body 110 and the sleeve 120 are connected to form a chamber 140 for accommodating the valve core assembly 130. The valve body 110 has an annular portion 111, and the annular portion 111 is sleeved on the outer periphery of the sleeve 120. The coil component 200 includes a coil assembly 210 and a sealing ring 220. At least part of the coil assembly 210 is sleeved on the outer periphery of the sleeve 120. The coil assembly 210 is coupled to the valve core assembly 130. The sealing ring 220 is fixedly connected to the coil assembly 210, and is sleeved on the outer periphery of the annular portion 111, and is sealed between the annular portion 111 and the coil assembly 210.

[0065] The electronic expansion valve of the embodiment of the present application, on the one hand, can improve the sealing between the valve component 100 and the coil component 200 by arranging a sealing ring 220 between the annular portion 111 and the coil assembly 210, thereby preventing external water vapor or impurities from entering the coil assembly 210, thereby reducing the risk of corrosion of the coil assembly 210, thereby improving the working performance and service life of the coil assembly 210; on the other hand, the sealing ring 220 is sleeved on the outer periphery of the annular portion 111, and is not in direct contact with the sleeve 120. In this way, in the process of sleeve-arranging the coil component 200 on the outer periphery of the sleeve 120, the sealing ring 220 will not generate contact friction with the sleeve 120, and there is also a gap for the air between the coil component 200 and the sleeve 120 to be discharged, thereby improving the installation efficiency of the electronic expansion valve.

[0066] The coil assembly 210 is coupled to the valve core assembly 130, so that when the electronic expansion valve is working, by applying a pulse signal to the coil assembly 210, the valve core assembly 130 can be driven to move, thereby adjusting the opening of the valve port to achieve control of the fluid flow.

[0067] like Figure 1 and Figure 2 As shown, the valve component 100 further includes a valve seat 150, and the valve body 110 is mounted on the valve seat 150. The valve seat 150 has a mounting cavity 151, and at least part of the valve body 110 is located in the mounting cavity 151. The outer surface of the valve seat 150 has an inlet 153 and an outlet 154, and the inlet 153 and the outlet 154 are connected to the mounting cavity 151.

[0068] Of course, in other embodiments, the electronic expansion valve may not include the valve seat 150 , and the valve body 110 may be directly installed in the refrigeration system.

[0069] like Figure 2 As shown, the valve body 110 includes a connecting sleeve 112 and a connecting ring 113. The connecting sleeve 112 is sealed and welded with the sleeve 120 to form a chamber 140; the connecting ring 113 is fixedly sleeved on the outer periphery of the connecting sleeve 112, and the connecting ring 113 has an annular portion 111. At least part of the connecting sleeve 112 and at least part of the connecting ring 113 are both located in the installation cavity 151, and the connecting ring 113 is threadedly connected to the valve seat 150.

[0070] It can be understood that the connecting ring 113 is threadedly connected to the valve seat 150, thereby forming a seal at the connection between the connecting ring 113 and the valve seat 150, thereby preventing external water vapor from entering the gap between the connecting ring 113 and the valve seat 150 into the gap between the connecting ring 113 and the connecting sleeve 112 and then flowing into the coil assembly 210.

[0071] The connecting sleeve 112 and the connecting ring 113 may be an integral structure or a separate structure. When the connecting sleeve 112 and the connecting ring 113 are separate structures, the connecting ring 113 and the connecting sleeve 112 may be fixedly connected by interference fit, screw connection, welding, etc.

[0072] like Figure 2 and Figure 3 As shown, the connecting sleeve 112 is connected to the sleeve 120 through the welding portion 114, and the connecting ring 113 is covered on the welding portion 114. In the embodiment of the present application, the connecting ring 113 is covered on the welding portion 114, that is, the welding portion 114 is located on the inner side of the connecting ring 113, and the sealing ring 220, the connecting ring 113 and the valve seat 150 protect the welding portion 114, further preventing the external water vapor from flowing to the welding portion 114 and causing corrosion to the welding portion 114.

[0073] The outer periphery of the connecting sleeve 112 has a first limiting portion 112 a , and the sleeve 120 abuts against the first limiting portion 112 a .

[0074] In one embodiment, the first limiting portion 112a is a step structure, and the sleeve 120 abuts against a step surface of the step structure.

[0075] like Figure 3 As shown, the connecting ring 113 also includes a ring body 113a located in the installation cavity 151, and the ring body 113a is fixedly sleeved on the outer peripheral surface of the connecting sleeve 112 and threadedly connected to the valve seat 150. The ring body 113a can be connected to the connecting sleeve 112 by interference fit, thread connection, welding, etc.

[0076] The annular portion 111 is convexly disposed on a surface of the ring body 113a facing the coil assembly 210, and there is a gap between the inner circumference of the annular portion 111 and the outer circumference of the sleeve 120. When the connecting sleeve 112 and the connecting ring 113 are separate structures, the annular body 113a can be fixedly connected to the connecting sleeve 112 by interference fit, and the inner circumference of the annular portion 111 and the outer circumference of the sleeve 120 are gap-fitted, so the gap can reduce the difficulty of assembling the connecting sleeve 112 and the connecting ring 113.

[0077] As an example, the surface of the ring body 113a on one side facing the coil assembly 210 is flush with the outer surface of the valve seat 150. In other words, the ring body 113a is neither higher than the outer surface of the valve seat 150 nor lower than the outer surface of the valve seat 150. On the one hand, the consistency of the appearance of the valve seat 150 and the ring body 113a is improved; on the other hand, the formation of a space for storing impurities on the top surface of the ring body 113a due to the ring body 113a being lower than the outer surface of the valve seat 150 is avoided.

[0078] like Figure 3 and Figure 4 As shown, the coil component 200 further includes a limiting member 230 , which is fixedly connected to the coil assembly 210 and limits the sealing ring 220 between the limiting member 230 and the coil assembly 210 .

[0079] In one embodiment, the coil assembly 210 has a bottom surface 211 facing the valve seat 150, and the limit member 230 is fixedly connected to the bottom surface 211; the coil assembly 210 also has a sinking groove 212, which is recessed from the bottom surface 211 along the axial direction of the valve core assembly 130 toward the top direction of the coil assembly 210; the sealing ring 220 and the part of the annular portion 111 surrounded by the sealing ring 220 are both located in the sinking groove 212, and the sealing ring 220 abuts between the bottom surface of the sinking groove 212 and the limit member 230.

[0080] In the embodiment of the present application, the limiting member 230 limits the sealing ring 220 in the sinking groove 212 of the coil assembly 210 , thereby reducing the volume of the electronic expansion valve along the axial direction of the valve core assembly 130 .

[0081] In one embodiment, the inner circumference of the sealing ring 220 is interference fit with the outer circumference of the annular portion 111. The sealing ring 220 and the annular portion 111 are interference fit, which can ensure the firmness of the connection of the sealing ring 220 and further ensure the sealing performance of the sealing ring 220.

[0082] like Figure 3 As shown, the annular portion 111 has an annular groove 111a on one side facing away from the sleeve 120, and at least part of the sealing ring 220 is located in the annular groove 111a. In the embodiment of the present application, the inner circumference of the sealing ring 220 is interference fit with the bottom surface of the annular groove 111a.

[0083] like Figure 5 As shown, a first annular convex rib 221 is provided on one side surface of the sealing ring 220 facing the limiting member 230, and the first annular convex rib 221 surrounds the outer circumference of the sleeve 120 and abuts against the limiting member 230; and / or, a second annular convex rib 222 is provided on one side surface of the sealing ring 220 facing the bottom surface of the sinking groove 212 of the coil assembly 210, and the second annular convex rib 222 surrounds the outer circumference of the sleeve 120 and abuts against the bottom surface of the sinking groove 212 of the coil assembly 210.

[0084] In the embodiment of the present application, the sealing ring 220 is provided with a first annular convex rib 221 and / or a second annular convex rib 222. After the annular convex rib is compressed, the sealing ring 220 can produce a larger deformation. The deformation force drives the inner circumferential surface of the sealing ring 220 to become an arc shape. The arc-shaped sealing ring 220 is sealed with the annular portion 111, thereby improving the sealing performance of the sealing ring 220.

[0085] like Figure 6 As shown, the cavity wall of the installation cavity 151 has a second limiting portion 152, and the outer periphery of the connecting sleeve 112 is provided with a stopper 112b abutting against the second limiting portion 152. The ring body 113a of the connecting ring 113 presses against the stopper 112b, and there is a gap between the ring body 113a and the second limiting portion 152.

[0086] It should be noted that when installing the electronic expansion valve, the sleeve 120 and the connecting sleeve 112 can be connected first, for example, by welding, and then the connecting ring 113 and the connecting sleeve 112 can be connected as a whole, for example, by interference fit, and then the valve body 110 can be installed in the installation cavity 151 of the valve seat 150. Thereafter, the coil assembly 210 can be installed. During the installation of the coil assembly 210, the coil assembly 210 and the sleeve 120 are in a non-sealed state, and the air in the cavity between the coil assembly 210 and the sleeve 120 can be discharged. Finally, the sealing ring 220 is installed to the outer periphery of the annular portion 111, and the space between the coil assembly 210 and the sleeve 120 is closed.

[0087] In the embodiment of the present application, the connecting ring 113 does not directly contact the second limiting portion 152, and the stopper 112b of the connecting sleeve 112 abuts against the second limiting portion 152. The advantage of such a design is that when the valve body 110 is installed in the installation cavity 151 of the valve seat 150, after the stopper 112b of the connecting sleeve 112 abuts against the second limiting portion 152, the torque of the threaded structure of the connecting ring 113 and the valve seat 150 can reach the target value, ensuring that the connecting sleeve 112 is completely pressed by the connecting ring 113, thereby ensuring the stability of the connection between the connecting sleeve 112, the connecting ring 113 and the valve seat 150, and avoiding the loosening of the connecting sleeve 112 due to the loosening of the threaded structure between the connecting ring 113 and the valve seat 150. A notch 113b is provided on the side of the connecting ring 113 facing the second limiting portion 152, and at least part of the stopper 112b is located in the notch 113b. If the connecting ring 113 is in direct contact with the second limiting portion 152 , the stopping portion 112 b in the notch 113 b may be loosely fixed or may be squeezed and deformed.

[0088] In one embodiment, the second limiting portion 152 is a step structure, and the stopping portion 112 b abuts against a step surface of the step structure.

[0089] In summary, the electronic expansion valve of the embodiment of the present application has at least the following advantages and beneficial effects:

[0090] The electronic expansion valve of the embodiment of the present application, on the one hand, can improve the sealing between the valve component 100 and the coil component 200 by arranging a sealing ring 220 between the annular portion 111 and the coil assembly 210, thereby preventing external water vapor or impurities from entering the coil assembly 210, thereby reducing the risk of corrosion of the coil assembly 210, thereby improving the working performance and service life of the coil assembly 210; on the other hand, the sealing ring 220 is sleeved on the outer periphery of the annular portion 111, and is not in direct contact with the sleeve 120. In this way, in the process of sleeve-arranging the coil component 200 on the outer periphery of the sleeve 120, the sealing ring 220 will not generate contact friction with the sleeve 120, and there is also a gap for the air between the coil component 200 and the sleeve 120 to be discharged, thereby improving the installation efficiency of the electronic expansion valve.

[0091] It is understandable that the various embodiments / implementations provided in the present application can be combined with each other without causing any contradiction, and will not be illustrated one by one here.

[0092] In the application embodiments, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise expressly defined. The terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the application embodiments can be understood according to the specific circumstances.

[0093] In the description of the application embodiments, it should be understood that the directions or positional relationships indicated by the terms "up", "down", "left", "right", "front", "back", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the application embodiments and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, should not be understood as a limitation on the application embodiments.

[0094] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the application embodiment. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0095] The above are only preferred embodiments of the application embodiments and are not intended to limit the application embodiments. For those skilled in the art, the application embodiments may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application embodiments shall be included in the protection scope of the application embodiments.

Claims

1. An electronic expansion valve, characterized in that: include: A valve component (100) comprises a valve body (110) and a sleeve (120), wherein the valve body (110) and the sleeve (120) are connected; the valve body (110) has an annular portion (111), and the annular portion (111) is sleeved on the outer circumference of the sleeve (120); and The coil component (200) comprises a coil assembly (210) and a sealing ring (220), wherein at least a portion of the coil assembly (210) is sleeved on the outer periphery of the sleeve (120); the sealing ring (220) is fixedly arranged on the coil assembly (210), sleeved on the outer periphery of the annular portion (111), and sealed between the annular portion (111) and the coil assembly (210).

2. The electronic expansion valve according to claim 1, characterized in that: The coil component (200) further includes: A limiting member (230) is fixedly disposed on the coil assembly (210), and the sealing ring (220) is limited between the limiting member (230) and the coil assembly (210).

3. The electronic expansion valve according to claim 2, characterized in that: The coil assembly (210) has a bottom surface (211), and the limiting member (230) is fixedly connected to the bottom surface (211); the coil assembly (210) further has a sinking groove (212), and the sinking groove (212) is recessed from the bottom surface (211) along the axial direction of the electronic expansion valve toward the top of the coil assembly (210); The sealing ring (220) and the portion of the annular portion (111) surrounded by the sealing ring (220) are both located in the sinking groove (212), and the sealing ring (220) abuts between the bottom surface of the sinking groove (212) and the limiting member (230).

4. The electronic expansion valve according to claim 2, characterized in that: A first annular convex rib (221) is provided on a surface of the sealing ring (220) on one side facing the limiting member (230), and the first annular convex rib (221) abuts against the limiting member (230); and / or, A second annular convex rib (222) is provided on a surface of the sealing ring (220) facing the coil assembly (210), and the second annular convex rib (222) abuts against the coil assembly (210).

5. The electronic expansion valve according to claim 1, characterized in that: The inner circumferential surface of the sealing ring (220) is interference-fitted with the outer circumferential surface of the annular portion (111).

6. The electronic expansion valve according to any one of claims 1 to 5, characterized in that: The valve body (110) comprises: A connecting sleeve (112) connected to the sleeve (120); and A connecting ring (113) is fixedly sleeved on the outer periphery of the connecting sleeve (112), and the connecting ring (113) has the annular portion (111).

7. The electronic expansion valve according to claim 6, characterized in that: The connecting sleeve (112) is connected to the sleeve (120) via a welding portion (114), and the connecting ring (113) is covered on the welding portion (114).

8. The electronic expansion valve according to claim 6, characterized in that: The connecting ring (113) and the connecting sleeve (112) are interference fit.

9. The electronic expansion valve according to claim 6, characterized in that: The valve component (100) further comprises a valve seat (150), wherein the valve seat (150) has an installation cavity (151); at least a portion of the connecting sleeve (112) and at least a portion of the connecting ring (113) are both located in the installation cavity (151), and the connecting ring (113) is threadedly connected to the valve seat (150).

10. The electronic expansion valve according to claim 9, characterized in that: The cavity wall of the installation cavity (151) has a second limiting portion (152); A stopper (112b) abutting against the second limiting portion (152) is provided on the outer periphery of the connecting sleeve (112); the connecting ring (113) presses against the stopper (112b) and has a gap with the second limiting portion (152).

11. The electronic expansion valve according to claim 9, characterized in that: The connecting ring (113) further comprises a ring body (113a) located in the installation cavity (151); the ring body (113a) is fixedly sleeved on the outer peripheral surface of the connecting sleeve (112) and is threadedly connected to the valve seat (150); The annular portion (111) is protruding from a surface of the ring body (113a) facing the coil assembly (210), and a gap is provided between the inner circumference of the annular portion (111) and the outer circumference of the sleeve (120).

12. The electronic expansion valve according to any one of claims 1 to 5, characterized in that: The side of the annular portion (111) facing away from the sleeve (120) also has an annular groove (111a), and at least a portion of the sealing ring (220) is located in the annular groove (111a).

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