CN107566569B - Housing, mobile terminal and method for making housing - Google Patents

Abstract

The present invention discloses a kind of shell; applied to mobile terminal; shell includes Housing base piece, middle layer and protective layer; Housing base piece has the outer surface being oppositely arranged and inner surface and the through-hole that inner surface is through to from outer surface; middle layer includes the first part positioned at outer surface, the second part of the hole wall positioned at through-hole and the transition portion that is connected between first part and second part; lateral surface of the transition portion far from Housing base piece is cambered surface, and protective layer covers first part and transition portion.The yields of above-mentioned shell is high.Invention additionally discloses a kind of mobile terminal and method for producing shell.

Description

Housing, mobile terminal and method for making housing

technical field

The present invention relates to the technical field of electronic equipment, and in particular, to a casing, a mobile terminal and a method for manufacturing the casing.

Background technique

In order to improve the user's holding experience, most of the side parts of the existing mobile phone casings are designed in an arc shape, so a sharp angle is formed between the hole wall of the button hole arranged on the side part and the outer surface of the side part, so that the periphery of the button hole is formed. The paint adhesion in the area is low and it is easy to fall off, resulting in a low yield of the casing.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a casing with a high yield rate, a mobile terminal and a method for manufacturing the casing.

The embodiment of the present invention adopts the following technical solutions:

In one aspect, a case is provided, applied to a mobile terminal, the case includes a case base, an intermediate layer and a protective layer, the case base has an outer surface and an inner surface disposed oppositely and a base from the outer surface is provided. a through hole whose surface penetrates to the inner surface, the intermediate layer includes a first part located on the outer surface, a second part located on the hole wall of the through hole, and connected between the first part and the second part The transition portion between the transition portions, the outer side surface of the transition portion away from the housing base piece is an arc surface, and the protective layer covers the first portion and the transition portion.

In another aspect, a mobile terminal is also provided, including the above casing.

In yet another aspect, a method for manufacturing a casing is also provided, comprising:

forming a through hole on the housing base, wherein the housing base has an outer surface and an inner surface oppositely disposed, the through hole penetrates from the outer surface to the inner surface;

An intermediate layer is formed on the housing base, wherein the intermediate layer includes a first portion on the outer surface, a second portion on the hole wall of the through hole, and a second portion connecting the first portion and the first portion. A two-part transition portion, the outer side of the transition portion away from the housing base member is an arc surface; and

A protective layer is formed on the housing base to form a housing, wherein the protective layer covers the first portion and the transition portion.

In the embodiment of the present invention, since the junction between the outer surface of the shell base member and the hole wall of the through hole is surrounded by the transition portion of the intermediate layer, and the outer side of the transition portion away from the shell base member is an arc surface, The protective layer covers the outer surface of the transition part, so the adhesion of the protective layer on the intermediate layer is strong, so that the protective layer can be firmly connected to the base part of the shell, and the protective layer is not easy to fall off, thus avoiding the appearance of the shell and improving the shell. body yield. Since the protective layer continuously covers the first part and the transition part, the firmness of the protective layer covering the transition part can be enhanced, and the protective layer can be further prevented from falling off.

Description of drawings

In order to illustrate the technical solutions of the present invention more clearly, the following will briefly introduce the accompanying drawings used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, which are common in the art. As far as technical personnel are concerned, other drawings can also be obtained from these drawings without creative labor.

FIG. 1 is a schematic structural diagram of a mobile terminal according to an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a casing of the mobile terminal shown in FIG. 1 .

FIG. 3 is a schematic structural diagram of an embodiment of the housing shown in FIG. 2 .

FIG. 4 is an enlarged schematic view of the structure at A in FIG. 3 .

FIG. 5 is a schematic structural diagram of an embodiment of a housing base of the housing shown in FIG. 2 .

FIG. 6 is a schematic structural diagram of another embodiment of the housing base of the housing shown in FIG. 2 .

FIG. 7 is a schematic structural diagram of another embodiment of the housing shown in FIG. 2 .

FIG. 8 is another schematic structural diagram of the housing base member shown in FIG. 6 .

FIG. 9 is another schematic structural diagram of the housing base member shown in FIG. 5 .

10 is a schematic structural diagram of a combined knife in a method for manufacturing a casing provided by an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Furthermore, the following descriptions of the various embodiments refer to the accompanying drawings to illustrate specific embodiments in which the invention may be practiced. Directional terms mentioned in the present invention, such as "up", "down", "front", "rear", "left", "right", "inside", "outside", "side", etc., only Reference is made to the directions of the accompanying drawings, therefore, the directional terms used are for better and clearer description and understanding of the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, in a specific orientation construction and operation, and therefore should not be construed as limiting the invention.

In the description of the present invention, it should be noted that, unless otherwise expressly specified and limited, the terms "installed", "connected", "connected" and "disposed on" should be interpreted in a broad sense, for example, it may be The fixed connection can also be a detachable connection or an integral connection; it can be a mechanical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication of the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

Also, in the description of the present invention, unless otherwise specified, "plurality" means two or more. If the term "process" appears in this specification, it not only refers to an independent process, but also includes in this term as long as the intended function of the process can be achieved when it cannot be clearly distinguished from other processes. In addition, the numerical range represented by "-" in this specification means the range which includes the numerical value described before and after "-" as a minimum value and a maximum value, respectively. In the drawings, structurally similar or identical elements are denoted by the same reference numerals.

Referring to FIGS. 1 to 3 , an embodiment of the present application provides a casing 1 , and the casing 1 can be applied to a mobile terminal 100 . The casing 1 includes a casing base 11 , an intermediate layer 12 and a protective layer 13 . The housing base 11 has an outer surface 111 and an inner surface 112 disposed opposite to each other, and a through hole 113 penetrating from the outer surface 111 to the inner surface 112 . Other components of the mobile terminal 100 may be matched with the casing 1 through the through holes 113 .

Please refer to FIG. 3 and FIG. 4 in combination, the intermediate layer 12 includes a first part 121 located on the outer surface 111 , a second part 122 located on the hole wall 1130 of the through hole 113 , and a transition connecting between the first part 121 and the second part 122 Section 123. At this time, the boundary between the outer surface 111 and the hole wall 1130 of the through hole 113 is wrapped by the transition portion 123 . In other words, the through hole 113 forms an opening 1131 on the outer surface 111 of the housing base 11 (as shown in FIG. 5 ), and the transition portion 123 completely wraps the edge of the opening 1131 along the extending direction thereof. The transition portion 123 includes opposing inner and outer sides 1232 . The inner side of the transition portion 123 is connected to the housing base 11 . The outer side 1232 of the transition portion 123 faces away from the housing base 11 . The outer side surface 1232 of the transition portion 123 is an arc surface. The protective layer 13 covers the first portion 121 and the transition portion 123 .

In the embodiment of the present application, since the interface between the outer surface 111 of the housing base 11 and the hole wall 1130 of the through hole 113 is wrapped by the transition portion 123 of the intermediate layer 12, and the transition portion 123 is far away from the housing base The outer side 1232 of 11 is an arc surface, and the protective layer 13 covers the outer side 1232 of the transition part 123, so the adhesion of the protective layer 13 on the intermediate layer 12 is strong, so that the protective layer 13 can be firmly connected to the shell base 11, The protective layer 13 is not easy to fall off, so as to avoid appearance defects of the casing 1 and improve the yield of the casing 1 . Since the protective layer 13 continuously covers the first part 121 and the transition part 123 , the firmness of the protective layer 13 covering the transition part 123 can be enhanced, and the protective layer 13 can be further prevented from falling off.

It can be understood that the area of the first part 121 covering the hole wall 1130 of the through hole 113 is larger than the first preset value, so that the first part 121 is firmly connected to the hole wall 1130 of the through hole 113 . The area of the second part 122 covering the outer surface 111 of the housing base 11 is larger than the second preset value, so that the second part 122 is firmly connected to the outer surface 111 of the housing base 11 . The first preset value and the second preset value are set according to the size of the opening 1131 and the size of the included angle between the hole wall 1130 of the through hole 113 and the outer surface 111 of the housing base 11 . Since the first part 121 , the transition part 123 and the second part 122 of the intermediate layer 12 are continuous, the first part 121 and the second part 122 help the transition part 123 to firmly wrap between the outer surface 111 and the hole wall 1130 of the through hole 113 junction. The transition portion 123 generally forms a rounded corner between the first portion 121 and the second portion 122 . At this time, the intermediate layer 12 may use a material with a relatively large consistency to ensure the continuity of the first part 121 , the transition part 123 and the second part 122 . At the same time, since the parts of the intermediate layer 12 facing the outside of the casing 1 (the transition part 123 , the first part 121 ) are covered by the protective layer 13 , the integrity of the appearance of the casing 1 can be ensured, thereby improving user experience.

In one embodiment, referring to FIG. 2 in conjunction, the housing 1 includes a bottom portion 15 and a side portion 16 disposed around the bottom portion 15 . The bottom 15 can be used as a back cover of the mobile terminal 100, and the side 16 can be used as a frame of the mobile terminal 100, and the frame and the back cover are integrally formed. Of course, in other embodiments, the casing 1 may only be provided with the side portion 16 , that is, the casing 1 serves as a frame of the mobile terminal 100 . The bottom portion 15 and the side portion 16 together define a receiving space 14 . The inner surface 112 of the housing base member 11 faces the accommodating space 14 , and the outer surface 111 of the housing base member 11 is away from the accommodating space 14 . The accommodating space 14 is used for accommodating components of the mobile terminal 100 , such as a battery, a motherboard, and the like. The through hole 113 may be provided through the side portion 16 .

In an embodiment, please refer to FIG. 1 and FIG. 2 in combination, the through hole 113 can be used as a button hole of the casing 1, and the button modules (2, 3) of the mobile terminal 100 are fixed on the casing 1 through the button hole, The keys of the key modules (2, 3) close the key holes, and the shapes of the key holes are adapted to the key shapes of the key modules (2, 3). The key module (2, 3) can be a volume key module 2 or a power key module 3. In another embodiment, the through hole 113 can also be used as a card tray socket of the casing 1, the tray 4 of the mobile terminal 100 is fixed on the casing 1 through the tray socket, and the limit plate of the tray 4 is closed Cato socket, the shape of the cato socket is adapted to the shape of the limit plate of the cato 4.

Optionally, the viscosity of the material of the intermediate layer 12 is greater than that of the material of the protective layer 13 . In this embodiment, the intermediate layer 12 is made of a material with a relatively high viscosity, so that it can be firmly attached to the outer surface 111 of the housing base 11 and the hole wall 1130 of the through hole 113 . The protective layer 13 may adopt a material with a lower viscosity than that of the intermediate layer 12 . For example, the intermediate layer 12 is made of ink material, and the protective layer 13 is made of paint material.

As an optional embodiment, please refer to FIG. 6 and FIG. 7 in combination, the housing base 11 further includes a chamfer 114 , and the chamfer 114 is connected to the outer surface 111 of the housing base 11 and the hole wall 1130 of the through hole 113 . between. The transition portion 123 of the intermediate layer 12 covers the chamfer 114 .

In this embodiment, since the housing base 11 is provided with the chamfer 114, it can avoid forming a sharp angle between the outer surface 111 of the housing base 11 and the hole wall 1130 of the through hole 113, increasing the transition The area of the inner side surface of the part 123 (the surface connecting the chamfer 114 ) is favorable for the transition part 123 to firmly wrap the junction between the outer surface 111 of the housing base 11 and the hole wall 1130 of the through hole 113, so that the protective layer 13 makes it possible to connect the housing base 11 more firmly. The setting of the chamfer 114 can also prevent the casing 1 from scratching the user, thereby improving the user experience.

Optionally, referring to FIGS. 6 to 8 , the chamfer 114 is a uniform chamfer to reduce the difficulty of forming the transition portion 123 on the chamfer 114 , so that the transition portion 123 is firmly connected to the chamfer 114 . Uniform chamfering refers to the chamfering 114 whose angle α and right-angled side length L are constant in the extending direction thereof. At the same time, the uniform chamfer 114 has a good degree of cooperation with other structures in the mobile terminal 100 (eg, a limit plate, a button), and the connection relationship is stable. For example, a locking structure adapted to the chamfer 114 can be provided on the limiting plate, so that the limiting plate can be firmly fixed on the casing 1 through the cooperation between the locking structure and the chamfer 114 . Of course, in other embodiments, the chamfer 114 may also be a non-uniform chamfer, that is, a chamfer with a constant angle but a change in the length of the right-angled side.

As an optional embodiment, please refer to FIG. 3 and FIG. 4 in combination, in the direction parallel to the axis 1132 of the through hole 113 , the length T1 of the second portion 122 is less than the depth T2 of the through hole 113 . At this time, the area of the through hole 113 close to the accommodating space 14 can maintain a relatively large diameter, so as to prevent the through hole 113 from being unfavorable for cooperation with other components because the diameter of the through hole 113 is too small.

In this embodiment, the setting of the second part 122 makes the diameter of the area of the through hole 113 far away from the receiving space 14 (the area into which the second part 122 extends) is larger than the diameter of the area of the through hole 113 close to the receiving space 14 . The thickness of the middle layer 12 is very thin, so the second part 122 can appropriately improve the sealing performance of the casing 1 and prevent external dust from entering the interior of the casing 1 without hindering the cooperation between the through hole 113 and other parts.

As an optional embodiment, referring to FIG. 3 , FIG. 4 and FIG. 9 , the outer surface 111 of the housing base 11 includes a peripheral area 1111 disposed around the through hole 113 and a peripheral area 1112 disposed around the peripheral area 1111 . The first portion 121 covers the peripheral area 1111 so that the intermediate layer 12 securely wraps the junction between the outer surface 111 of the housing base 11 and the hole wall 1130 of the through hole 113 . The protective layer 13 also covers the peripheral region 1112 . At this time, the protective layer 13 continuously covers the transition portion 123 , the first portion 121 and the peripheral region 1112 , so as to provide all-round protection to the casing 1 .

Optionally, as shown in FIG. 4 , in the vertical direction of the outer surface 111 , the thickness S1 of the portion of the protective layer 13 covering the first portion 121 is smaller than the thickness S2 of the portion of the protective layer 13 covering the peripheral region 1112 . At this time, the appearance surface 131 of the protective layer 13 away from the casing base 11 is relatively flat, so that the appearance of the casing 1 is strong, and it can prevent the user's feeling of holding the casing 1 from being reduced due to the uneven appearance, so as to improve the overall appearance of the casing 1 . user experience. For example, the sum of the thickness S1 of the portion of the protective layer 13 covering the first portion 121 and the thickness S3 of the first portion 121 is equal to the thickness S2 of the portion of the protective layer 13 covering the peripheral region 1112 .

Please refer to FIG. 1 to FIG. 9 together. An embodiment of the present application further provides a mobile terminal 100. The mobile terminal 100 includes the casing 1 described in the above embodiments. The mobile terminal 100 can avoid appearance defects caused by the peeling off of the protective layer 13, and the yield rate is high. The mobile terminal 100 involved in this embodiment of the present invention may be any device with communication and storage functions, such as a tablet computer, a mobile phone, an electronic reader, a remote control, a personal computer (PC), a notebook computer, a vehicle-mounted device, a network Smart devices with network functions such as TVs and wearable devices. The mobile terminal 100 further includes a volume key module 2 , a power key module 3 , and a card tray 4 . The mobile terminal 100 further includes a main board, a battery, a touch screen and the like accommodated in the casing 1 .

Please refer to FIG. 1 to FIG. 10 together. An embodiment of the present application further provides a method for manufacturing a casing, which can be used to manufacture the casing 1 described in the above embodiments. The shell making method includes:

S01 : As shown in FIG. 3 , through holes 113 are formed in the case base 11 . The housing base 11 has an outer surface 111 and an inner surface 112 arranged opposite to each other, and the through hole 113 penetrates from the outer surface 111 to the inner surface 112 .

S03 : As shown in FIGS. 3 and 4 , the intermediate layer 12 is formed on the case base 11 . The intermediate layer 12 includes a first part 121 located on the outer surface 111 , a second part 122 located on the hole wall 1130 of the through hole 113 , and a transition part 123 connecting the first part 121 and the second part 122 , and the transition part 123 is far away from the shell base The outer side surface 1232 of the member 11 is an arc surface. At this time, the interface between the outer surface 111 of the housing base 11 and the hole wall 1130 of the through hole 113 is wrapped by the transition portion 123 of the intermediate layer 12 .

Wherein, before performing this step, the housing base 11 may be cleaned to remove burrs and dirt on the housing base 11 . The intermediate layer 12 is made of a material with a relatively high viscosity so as to be firmly connected to the housing base 11 . For example, an ink material may be sprayed on the housing base 11 to form the intermediate layer 12 . In order to ensure the continuity of the intermediate layer 12, curing may be performed at the same time as spraying.

S04 : The protective layer 13 is formed on the case base 11 to form the case 1 . The protective layer 13 covers the first part 121 and the transition part 123 . Since the outer side surface 1232 of the transition portion 123 away from the housing base 11 is an arc surface, and the protective layer 13 covers the outer side surface 1232 of the transition portion 123, the protective layer 13 has a strong adhesion on the intermediate layer 12, so that the protective layer 13 has a strong adhesion force on the intermediate layer 12. 13 can be firmly connected to the housing base 11 , and the protective layer 13 is not easy to fall off, thereby avoiding the appearance of the housing 1 from being bad, and improving the yield of the housing 1 . Since the protective layer 13 continuously covers the first part 121 and the transition part 123 , the firmness of the protective layer 13 covering the transition part 123 can be enhanced, and the protective layer 13 can be further prevented from falling off.

Wherein, the viscosity of the material of the protective layer 13 may be smaller than that of the material of the intermediate layer 12 . For example, a paint material may be sprayed on the housing base 11 to form the protective layer 13 .

As an optional embodiment, please refer to FIG. 6 and FIG. 7 in combination, before the intermediate layer 12 is formed, the manufacturing method of the casing further includes:

S02 : A chamfer 114 is formed on the housing base 11 , and the chamfer 114 is connected between the outer surface 111 and the hole wall 1130 of the through hole 113 .

In the present embodiment, since the housing base 11 is provided with the chamfer 114, it can avoid forming a sharp angle between the outer surface 111 of the housing base 11 and the hole wall 1130 of the through hole 113, so that the cover is The area of the inner side surface of the transition portion 123 on the chamfer 114 is increased, so that the transition portion 123 can firmly wrap the junction between the outer surface 111 of the housing base 11 and the hole wall 1130 of the through hole 113, so that the protective layer 13 makes it possible to connect the housing base 11 more firmly. The setting of the chamfer 114 can also avoid scratching the user, thereby improving the user experience.

Optionally, please refer to FIG. 5 , FIG. 6 and FIG. 10 , in the same milling process, the through hole 113 and the chamfer 114 are formed on the housing base 11 by the combined cutter 5 . Since the shell manufacturing method processes the through holes 113 and the chamfers 114 on the shell base 11 through the same milling process, and the same milling process is completed on the same equipment, it can save the shell base 11 in adjacent processes. The time of circulation in the middle is shortened, and the processing time is shortened, so that the shell manufacturing method has high efficiency and low cost. At the same time, the same milling process only needs one positioning, and the positioning accuracy is high, so that the dimensional accuracy of the through hole 113 and the chamfer 114 is high, and the relative size tolerance between the chamfer 114 and the through hole 113 is extremely small, thereby improving the Product yield of case 1.

Optionally, before processing the through hole 113 (ie, step S01 ), the method for manufacturing the casing includes:

S001: The aluminum plate is formed by extrusion process.

S002: The aluminum plate is cut into the shell raw material of a single shell size. The size of the raw material of the casing is determined according to the size of the mobile terminal 100 .

S003 : Rough milling and fine milling are performed on the raw material of the shell to form the shell base 11 . Therein, the housing base 11 forms the base and the sides of the prototype. Machining of the bottom of the prototype to form the bottom 15 of the shell 1 and machining of the sides of the prototype to form the sides 16 of the shell 1 may continue in subsequent steps of the shell fabrication method. Through-holes 113 and chamfers 114 are machined into the side of the housing base part 11 of the prototype.

Optionally, as shown in FIG. 10 , the combined knife 5 includes a first segment of blade 51 and a second segment of blade 52 . Specifically, the combined knife 5 includes a handle portion 5a and a blade portion 5b, the handle portion 5a is fixed on the CNC machine tool, and the blade portion 5b is used to process the housing base 11 . The blade portion 5b of the combined knife 5 includes a first-section blade 51 and a second-section blade 52, and the second-section blade 52 is located between the first-section blade 51 and the handle portion 5a.

Wherein, the leading angle β of the first-stage cutting edge 51 is greater than the leading-edge angle γ of the second-stage cutting edge 52 . The first cutting edge 51 can be used for processing the through hole 113 , and the second cutting edge 52 can be used for processing the chamfer 114 . For example, the leading angle β of the first segment of the cutting edge 51 is 90°, so that the hole wall 1130 of the through hole 113 is a cylindrical surface. The leading angle γ of the second segment of the cutting edge 52 is 45° to 60°, so that the angle between the chamfer 114 and the outer surface 111 is greater than or equal to 90°, so as to avoid scratching the user.

Optionally, forming the through hole 113 and the chamfer 114 on the housing base 11 by the combined knife 5 includes:

The combined tool 5 moves along the first tool path to machine the through hole 113 on the housing base 11 . Wherein, as shown in FIG. 5 , the through hole 113 forms an opening 1131 on the outer surface 111 . Before moving along the first tool path, the combined knife 5 is positioned with the housing base 11 first.

The combined tool 5 is moved along the second tool path to machine a chamfer 114 on the housing base 11 . Wherein, as shown in FIGS. 6 and 8 , the trajectory of the second tool path is the same as the trajectory of the opening 1131 to make the chamfer 114 uniform. When the outer surface 111 is a curved surface (eg, an arc surface), the trajectory of the opening 1131 changes with the shape of the outer surface 111 . The second toolpath is a three-dimensional (3D) toolpath. The movement of the second segment of the blade 52 along the second tool path enables the chamfer 114 to be accurately formed at the outer end of the through hole 113 and the chamfer 114 to be uniform.

In other embodiments, the second toolpath can also be a two-dimensional (2D) toolpath. At this time, when the outer surface 111 is flat, the chamfer 114 is a uniform chamfer, and the angle of the chamfer 114 and the length of the right-angled side of the chamfer 114 are unchanged in the extending direction of the second tool path. When the outer surface 111 is an arc surface, the chamfer 114 is an uneven chamfer, the angle of the chamfer 114 is constant, and the length of the right-angled side of the chamfer 114 changes along the extending direction of the second tool path.

In other embodiments, the combined tool 5 can also move along a single third tool path to simultaneously process the through hole 113 and the chamfer 114 , thereby shortening the processing time and increasing the processing efficiency. At this time, when the outer surface 111 is flat, the chamfer 114 is a uniform chamfer, and the angle of the chamfer 114 and the length of the right-angled side of the chamfer 114 are unchanged in the extending direction of the third tool path. When the outer surface 111 is an arc surface, the chamfer 114 is an uneven chamfer, the angle of the chamfer 114 is constant, and the length of the right-angled side of the chamfer 114 changes along the extending direction of the third tool path.

The embodiments of the present invention have been introduced in detail above, and specific examples are used to illustrate the principles and implementations of the present invention. The descriptions of the above embodiments are only used to help understand the methods and core ideas of the present invention; at the same time, for Persons of ordinary skill in the art, according to the idea of the present invention, will have changes in the specific embodiments and application scope. To sum up, the contents of this specification should not be construed as limiting the present invention.

Claims (11)

1. A casing, applied to a mobile terminal, characterized in that the casing comprises a casing base, an intermediate layer and a protective layer, and the casing base has an outer surface and an inner surface arranged oppositely and a The outer surface penetrates through the through hole of the inner surface, and the intermediate layer includes a first part located on the outer surface, a second part located in the hole wall of the through hole, and connected between the first part and the first part. The transition part between the two parts, the outer side surface of the transition part away from the housing base is an arc surface, and the protective layer covers the first part and the transition part; Wherein, the viscosity of the material of the intermediate layer is greater than the viscosity of the material of the protective layer; Wherein, the protective layer adopts paint material. 2. The casing according to claim 1, wherein the intermediate layer is made of ink material. 3 . The casing according to claim 1 , wherein the casing base further comprises a chamfer, and the chamfer is connected between the outer surface and the hole wall of the through hole. 4 . In between, the transition portion covers the chamfer. 4. The casing of claim 3, wherein the chamfer is a uniform chamfer. 5 . The housing according to claim 1 , wherein, in a direction parallel to the axis of the through hole, the length of the second portion is smaller than the depth of the through hole. 6 . 6. The housing according to any one of claims 1 to 2, wherein the outer surface comprises a peripheral area provided around the through hole and a peripheral area provided around the peripheral area, the first portion Covering the peripheral area, the protective layer also covers the peripheral area; In a vertical direction of the outer surface, a thickness of a portion of the protective layer covering the first portion is smaller than a thickness of a portion of the protective layer covering the peripheral region. 7 . A mobile terminal, characterized in that, comprising the casing according to any one of claims 1 to 6 . 8. A method for making a shell, comprising: forming a through hole on the housing base, wherein the housing base has an outer surface and an inner surface oppositely disposed, the through hole penetrates from the outer surface to the inner surface; An intermediate layer is formed on the housing base, wherein the intermediate layer includes a first portion on the outer surface, a second portion on the hole wall of the through hole, and a second portion connecting the first portion and the first portion. A two-part transition portion, the outer side of the transition portion away from the housing base member is an arc surface; and forming a protective layer on the casing base to form a casing, wherein the protective layer covers the first portion and the transition portion; Wherein, the viscosity of the material of the intermediate layer is greater than the viscosity of the material of the protective layer; Wherein, the protective layer adopts paint material. 9 . The method for manufacturing a casing according to claim 8 , wherein before the intermediate layer is formed, the method for manufacturing the casing further comprises: forming a chamfer on the casing base, the chamfering A corner is connected between the outer surface and the hole wall of the through hole. 10 . The method for manufacturing a casing according to claim 9 , wherein, in the same milling process, the through hole and the chamfer are formed on the casing base member by a combined cutter. 11 . 11 . The method for manufacturing a casing according to claim 10 , wherein the forming the through hole and the chamfer on the casing base by using a combination knife comprises: 11 . the combined knife is moved along a first tool path to machine the through hole in the housing base, wherein the through hole forms an opening on the outer surface; and The combined tool moves along a second tool path to machine the chamfer on the housing base, wherein the trajectory of the second tool path is the same as the trajectory of the opening to make the chamfer evenly.