Pressure head and design method

Abstract

The invention discloses a pressure head and a design method, the pressure head comprises a pressure head body, a connecting part and a press fitting part, the connecting part is arranged at one end of the pressure head body and is used for connecting a press; the press-fitting part is arranged at the other end of the pressure head body and is used for press-fitting the bowl-shaped plug; wherein the press-fitting part comprises a center hole and an annular cambered surface, the center hole is formed in the center of the press-fitting part in the press-fitting direction of the bowl-shaped plug, and the inner side of the annular cambered surface surrounds the center hole. The contact area of the pressing head and the bowl-shaped plug is increased through the annular cambered surface, so that the contact stability of the pressing head and the bowl-shaped plug is improved, then the situation that the pressing head deviates before being pressed into the bowl-shaped plug is prevented, the bowl-shaped plug can be prevented from deforming in the press-fitting process and interfering with the pressing head due to the arrangement of the center hole, and the press-fitting quality of the bowl-shaped plug is improved. And the press fitting success rate of the bowl-shaped plug is improved.

Description

Technical Field

[0001] The invention relates to the technical field of machining, and in particular to a pressing head and a design method thereof. Background Art

[0002] In the field of shell machining, bowl-shaped plug press-fitting is a commonly used method for hole sealing. The specific method is: first, a layer of anaerobic glue is applied all around the hole in the shell machining hole through a mechanism, and then the bowl-shaped plug is press-fitted into the shell through a pressure head. Force sensors and displacement sensors are used to monitor the press-fitting process to ensure the sealing between the bowl-shaped plug and the shell hole, ultimately achieving the purpose of preventing liquid leakage.

[0003] In the prior art, the fit between the bowl-shaped plug and the shell is generally an interference fit. During the press-fitting process, an extrusion force is generated between the bowl-shaped plug and the shell. During the pressing process, the bowl-shaped plug is subjected to friction resistance from the shell. The press drives the pressure head to overcome the friction resistance between the bowl-shaped plug and the shell and press the bowl-shaped plug into the shell.

[0004] However, since the bowl-shaped plug is a one-time molded part, the flatness and planarity of the bottom are not as good as those of machined parts. The current ram on the press is usually cylindrical. During the press-fitting process of the bowl-shaped plug, only the circumference of the ram pressing surface is in contact with the bowl-shaped plug, and a relatively smooth contact cannot be guaranteed before pressing. In most cases, the bowl-shaped plug is slightly tilted before the ram is pressed in, resulting in a low press-fitting success rate. Summary of the invention

[0005] The purpose of the present invention is to provide a pressure head and a design method, aiming to solve the problem that the existing pressure head cannot ensure relatively stable contact before pressing the bowl-shaped plug.

[0006] In order to solve the above technical problems, on the one hand, an embodiment of the present invention provides a pressing head for connecting to a press to press-fit a bowl-shaped plug, comprising: a pressing head body, a connecting portion and a pressing portion, wherein the connecting portion is arranged at one end of the pressing head body for connecting to the press; the pressing portion is arranged at the other end of the pressing head body for press-fitting a bowl-shaped plug; wherein the pressing portion comprises a center hole and an annular arc surface, wherein the center hole is arranged at the center of the pressing portion along the pressing direction of the bowl-shaped plug, and the inner side of the annular arc surface surrounds the outside of the center hole.

[0007] Furthermore, the press-fitting portion further includes an annular fillet, the inner side of the annular fillet is connected to the outer side of the annular arc surface, and the outer side of the annular fillet is connected to the outer side wall of the press-fitting portion.

[0008] Furthermore, the radius of the arc projection of the annular arc surface in the transverse direction of the center hole is greater than the radius of the arc projection of the bowl-shaped plug in the transverse direction of the center hole; the radius of the arc projection of the annular fillet in the transverse direction of the center hole is smaller than the radius of the arc projection of the bowl-shaped plug in the transverse direction of the center hole.

[0009] Furthermore, the press-fitting portion is cylindrical, and the radius of the center hole is half of the radius of the press-fitting portion.

[0010] Furthermore, the connecting portion includes a connecting hole, which passes through the pressing head body along the pressing direction of the bowl-shaped plug and is connected to the center hole.

[0011] The present invention increases the contact area between the pressure head and the bowl-shaped plug through the annular arc surface, thereby improving the contact stability between the pressure head and the bowl-shaped plug, and further preventing the bowl-shaped plug from shifting before the pressure head is pressed in. The setting of the center hole can prevent the deformation of the bowl-shaped plug during the press-fitting process from interfering with the pressure head, thereby improving the press-fitting success rate of the bowl-shaped plug.

[0012] On the other hand, the present invention also provides a method for designing a pressure head, comprising:

[0013] Obtain the required pressing force for the bowl-shaped plug according to the press-in force formula for interference fit;

[0014] The required pressing force is introduced into the actual pressing force formula of the pressing head, and the area relationship between the center hole and the annular arc surface is obtained;

[0015] According to the area calculation formula of the center hole, the area calculation formula of the annular arc surface, and the area relationship between the center hole and the annular arc surface, the relationship between the radius of the center hole and the angle of the annular arc surface is obtained;

[0016] The values ​​of the radius of the center hole and the angle of the annular arc surface are selected according to the relationship between the radius of the center hole and the angle of the annular arc surface and the size of the bowl-shaped plug.

[0017] Furthermore, the method of obtaining the press-fitting force required for pressing the bowl-shaped plug according to the interference fit press-fitting force formula includes:

[0018] The pressing force ΔP required for pressing the bowl-shaped plug into the x =P1*2π*R1*L1*f+Δε;

[0019] Among them, P1 is the contact stress exerted on the bowl-shaped plug when it is pressed into the press-fitting hole, R1 is the radius of the center hole, L1 is the length of the bowl-shaped plug pressed into the press-fitting hole, f is the friction between the bowl-shaped plug and the press-fitting hole, and Δε is the error value, which depends on the cylindricity, radius and roughness of the press-fitting hole.

[0020] Furthermore, the step of introducing the required press-fitting force into the actual press-fitting force formula of the press head and obtaining the area relationship between the center hole and the annular arc surface includes:

[0021] According to the actual pressing force ΔP of the pressing head 实 =(ΔS1-ΔS2)*P1*f=ΔP x Obtaining the area relationship between the center hole and the annular arc surface;

[0022] Wherein, ΔS1 is the area of ​​the annular arc surface, and ΔS2 is the area of ​​the central hole.

[0023] Furthermore, the relationship between the radius of the center hole and the angle of the annular arc surface is obtained according to the area calculation formula of the center hole, the area calculation formula of the annular arc surface, and the area relationship between the center hole and the annular arc surface, including:

[0024] The area of ​​the central hole ΔS2 = π*R1 2 ;

[0025] The area of ​​the annular arc surface ΔS1=(ɑ / 360°)*π*R2;

[0026] Wherein, ɑ is the angle of the annular arc surface, and R2 is the radius of the arc projection of the annular arc surface in the transverse direction of the center hole.

[0027] Furthermore, the value of the radius of the center hole and the angle of the annular arc surface is selected according to the size of the bowl-shaped plug, including:

[0028] The radius of the annular arc surface is selected according to the radius of the bowl-shaped plug;

[0029] Obtaining a relationship between the press-fit portion, the center hole, and the annular arc surface according to the radius of the annular arc surface;

[0030] Selecting the radius of the center hole according to the radius of the press-fitting portion;

[0031] The value of the angle of the annular arc surface is obtained according to a relationship between the press-fitting portion, the center hole and the annular arc surface.

[0032] The present invention infers the values ​​of the radius of the center hole of the required pressure head and the angle of the annular arc surface through the required pressing force of the bowl-shaped plug, and increases the contact area between the pressure head and the bowl-shaped plug through the annular arc surface, thereby improving the stability of the contact between the pressure head and the bowl-shaped plug, thereby preventing the bowl-shaped plug from shifting before the pressure head is pressed in. The setting of the center hole can prevent the deformation of the bowl-shaped plug during the pressing process from interfering with the pressure head, thereby improving the success rate of pressing the bowl-shaped plug. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0034] Figure 1 A schematic structural diagram of a first-viewing angle of an indenter provided by an embodiment of the present invention;

[0035] Figure 2 A schematic structural diagram of a second viewing angle of an indenter provided by an embodiment of the present invention;

[0036] Figure 3 A schematic structural diagram of a pressing head provided by an embodiment of the present invention from a third viewing angle;

[0037] Figure 4 A cross-sectional view AA provided for an embodiment of the present invention;

[0038] Figure 5 A schematic diagram of the structure of a bowl-shaped plug provided in an embodiment of the present invention;

[0039] Figure 6 A cross-sectional view BB is provided for an embodiment of the present invention;

[0040] Figure 7 A schematic flow chart of a method for designing a pressure head provided by an embodiment of the present invention;

[0041] Figure 8 A schematic diagram of a sub-flow diagram of a method for designing a pressure head provided in an embodiment of the present invention.

[0042] Description of the symbols in the figure:

[0043] 1. Indenter body;

[0044] 2. Connecting part; 21. Connecting hole;

[0045] 3. Press-fitting part; 31. Center hole; 32. Annular arc surface; 33. Annular fillet;

[0046] 4. Bowl-shaped plug. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0049] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0050] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0051] Compared with the bushings currently on the market, the pressure head, which is a combination of multiple components, can not only be used as a bushing, but also increase the function of the bushing, which has a better effect on automotive parts.

[0052] Combination Figure 1-6 As shown, the present invention provides a pressing head for connecting to a press to press-fit a bowl-shaped plug 4, comprising: a pressing head body 1, a connecting portion 2 and a pressing portion 3, wherein the connecting portion 2 is arranged at one end of the pressing head body 1 for connecting to the press; the pressing portion 3 is arranged at the other end of the pressing head body 1 for press-fitting the bowl-shaped plug 4; wherein the pressing portion 3 comprises a center hole 31 and an annular arc surface 32, wherein the center hole 31 is arranged at the center of the pressing portion 3 along the pressing direction of the bowl-shaped plug 4, and the inner side of the annular arc surface 32 surrounds the outside of the center hole 31.

[0053] In this embodiment, the connecting part 2 of the pressing head is connected to the press, and the pressing part 3 presses the bowl-shaped plug 4. The contact area between the pressing head and the bowl-shaped plug 4 is increased by the annular arc surface 32 on the pressing part 3, thereby improving the stability of the contact between the pressing head and the bowl-shaped plug 4, thereby preventing the bowl-shaped plug 4 from shifting before the pressing head is pressed in. The setting of the center hole 31 can prevent the deformation of the bowl-shaped plug 4 during the pressing process from interfering with the pressing head, thereby improving the success rate of pressing the bowl-shaped plug 4.

[0054] In some specific embodiments, the pressing part 3 is detachably connected to the other end of the pressing head body 1, and the pressing head can replace different pressing parts 3 according to the sizes of the bowl-shaped plug 4, so that the pressing head can be used to press bowl-shaped plugs 4 of different sizes.

[0055] In some embodiments, the press-fitting portion 3 further includes an annular fillet 33 , the inner side of the annular fillet 33 is connected to the outer side of the annular arc surface 32 , and the outer side of the annular fillet 33 is connected to the outer side wall of the press-fitting portion 3 .

[0056] In this embodiment, the annular fillet 33 provides a gap for the press-fitting of the bowl-shaped plug 4 . While the annular arc surface 32 presses the bowl-shaped plug 4 , the annular fillet 33 can help press the bowl-shaped plug 4 in.

[0057] In some embodiments, the radius of the arc projection of the annular arc surface 32 in the transverse direction of the central hole 31 is greater than the radius of the arc projection of the bowl-shaped plug 4 in the transverse direction of the central hole 31; the radius of the arc projection of the annular fillet 33 in the transverse direction of the central hole 31 is smaller than the radius of the arc projection of the bowl-shaped plug 4 in the transverse direction of the central hole 31. The radius of the arc projection of the annular arc surface 32 in the transverse direction of the central hole 31 is R2, the radius of the arc projection of the annular fillet 33 in the transverse direction of the central hole 31 is R3, and the radius of the arc projection of the bowl-shaped plug 4 in the transverse direction of the central hole 31 is R4.

[0058] In this embodiment, the radius R2 of the arc projection of the annular arc surface 32 in the transverse direction of the center hole 31 is greater than the radius R4 of the arc projection of the bowl-shaped plug 4 in the transverse direction of the center hole 31, which can ensure the contact area between the annular arc surface 32 and the bowl-shaped plug 4, avoid the existing pressure head only forming a circumferential contact with the bowl-shaped plug 4, and improve the stability of the contact between the pressure head and the bowl-shaped plug 4; the radius R3 of the arc projection of the annular fillet 33 in the transverse direction of the center hole 31 is smaller than the radius R4 of the arc projection of the bowl-shaped plug 4 in the transverse direction of the center hole 31, which can ensure that when the annular arc surface 32 abuts against the bowl-shaped plug 4, a certain gap is left at the annular fillet 33 to facilitate the pressing of the bowl-shaped plug 4.

[0059] In some specific embodiments, the radius of the arc projection of the annular arc surface 32 in the transverse direction of the center hole 31 is larger than the radius of the arc projection of the bowl-shaped plug 4 in the transverse direction of the center hole 31 by one tenth of the radius of the arc projection of the bowl-shaped plug 4 in the transverse direction of the center hole 31.

[0060] In this embodiment, R2=1.1R4, which can make the contact area between the annular arc surface 32 and the bowl-shaped plug 4 larger.

[0061] In some embodiments, the press-fitting portion 3 is cylindrical, and the diameter of the central hole 31 is half of the diameter of the press-fitting portion 3 .

[0062] In this embodiment, the setting of the center hole 31 can prevent the deformation of the bowl-shaped plug 4 during the press-fitting process from interfering with the pressing head. A smaller center hole 31 will cause the middle part of the bowl-shaped plug 4 to interfere with the annular arc surface 32 during the press-fitting process, affecting the press-fitting effect of the bowl-shaped plug 4. An excessively large center hole 31 will cause the contact area between the annular arc surface 32 and the bowl-shaped plug 4 to be reduced. The diameter of the center hole 31 is half of the diameter of the press-fitting portion 3, which can better ensure that the contact area between the annular arc surface 32 and the bowl-shaped plug 4 is larger and the deformation of the bowl-shaped plug 4 during the press-fitting process will not interfere with the annular arc surface 32.

[0063] In some embodiments, the connecting portion 2 includes a connecting hole 21 , which passes through the pressing head body 1 along the pressing direction of the bowl-shaped plug 4 and is connected to the central hole 31 .

[0064] In this embodiment, the connection hole 21 is used to connect the press. The connection hole 21 passes through the press head body 1 along the pressing direction of the bowl-shaped plug 4 and is connected to the center hole 31, which can save materials and reduce the production cost of the press head.

[0065] In some specific embodiments, the center hole 31 is inclined toward the connecting hole 21, which prevents the deformation of the bowl-shaped plug 4 during the press-fitting process from interfering with the annular arc surface 32, while ensuring the overall strength of the pressing head as much as possible.

[0066] Combination Figure 7 As shown, the present invention also provides a method for designing a pressure head, comprising steps S10 to S40:

[0067] S10, obtaining the required pressing force for pressing the bowl-shaped plug 4 according to the interference fit pressing force formula;

[0068] S20, introducing the required pressing force into the actual pressing force formula of the pressing head, and obtaining the area relationship between the center hole 31 and the annular arc surface 32;

[0069] S30, according to the area calculation formula of the center hole 31, the area calculation formula of the annular arc surface 32, and the area relationship between the center hole 31 and the annular arc surface 32, obtain the relationship between the radius of the center hole 31 and the angle of the annular arc surface 32;

[0070] S40 , selecting values ​​of the radius of the central hole 31 and the angle of the annular arc surface 32 according to the size of the bowl-shaped plug 4 .

[0071] The value of the angle of the annular arc surface 32 is the arc angle of the arc projection of the annular arc surface 32 in the transverse direction of the central hole 31 .

[0072] In the embodiment of the present invention, the radius of the center hole 31 of the required pressure head and the angle of the annular arc surface 32 are inferred by inversely analyzing the required pressing force of the bowl-shaped plug 4. The contact area between the pressure head and the bowl-shaped plug 4 is increased by the annular arc surface 32, thereby improving the stability of the contact between the pressure head and the bowl-shaped plug 4, thereby preventing the bowl-shaped plug 4 from shifting before the pressure head is pressed in. The setting of the center hole 31 can prevent the deformation of the bowl-shaped plug 4 during the pressing process from interfering with the pressure head, thereby improving the success rate of pressing the bowl-shaped plug 4.

[0073] In some embodiments, the press-fitting force required for pressing the bowl-shaped plug 4 is obtained according to the interference fit press-fitting force formula, including:

[0074] The pressing force ΔP required for pressing the bowl-shaped plug 4 x =P1*2π*R1*L1*f+Δε;

[0075] Among them, P1 is the contact stress that the bowl-shaped plug 4 is subjected to when it is pressed into the press-fitting hole, R1 is the radius of the center hole 31, L1 is the length of the bowl-shaped plug 4 pressed into the press-fitting hole, f is the friction between the bowl-shaped plug 4 and the press-fitting hole, and Δε is the error value, which depends on the cylindricity, diameter and roughness of the press-fitting hole.

[0076] In this embodiment, the bowl-shaped plug 4 is pressed into the press-fitting hole on the shell, and the bowl-shaped plug 4 has an interference fit with the press-fitting hole. The minimum press-fitting force required for pressing the bowl-shaped plug 4 is equal to the interference fit pressing force. Based on the relationship between the two, the size of the center hole 31 and the annular arc surface 32 of the pressure head are reversed.

[0077] In some specific embodiments, the contact stress P1=E / (4R1)*δ that the bowl-shaped plug 4 is subjected to when it is pressed into the press-fit hole max , where E is the elastic modulus of the material, δ max is the maximum tolerance of the press-fit hole.

[0078] In some embodiments, the required press-fitting force is introduced into the actual press-fitting force formula of the press head, and the area relationship between the center hole 31 and the annular arc surface 32 is obtained, including:

[0079] According to the actual pressing force ΔP of the pressing head 实 =(ΔS1-ΔS2)*P1*f=ΔP x Obtaining the area relationship between the central hole 31 and the annular arc surface 32;

[0080] Wherein, ΔS1 is the area of ​​the annular arc surface 32 , and ΔS2 is the area of ​​the central hole 31 .

[0081] In this embodiment, the area relationship between the center hole 31 and the annular arc surface 32 is obtained based on the actual pressing force of the pressure head being equal to the interference fit pressing force of the bowl-shaped plug 4 pressed into the press-fit hole on the shell, which facilitates the acquisition of the relationship between the radius of the center hole 31 and the angle of the annular arc surface 32.

[0082] In some embodiments, according to the area calculation formula of the central hole 31, the area calculation formula of the annular arc surface 32, and the area relationship between the central hole 31 and the annular arc surface 32, the relationship between the radius of the central hole 31 and the angle of the annular arc surface 32 is obtained, including:

[0083] The area of ​​the center hole 31 ΔS2=π*R1 2 ;

[0084] The area of ​​the annular arc surface 32 ΔS1=(ɑ / 360°)*π*R2;

[0085] Wherein, ɑ is the angle of the annular arc surface 32 , and R2 is the radius of the arc projection of the annular arc surface 32 in the transverse direction of the central hole 31 .

[0086] In this embodiment, an equation can be established based on the above-mentioned relationship, the area ΔS2 of the center hole 31, and the area ΔS1 of the annular arc surface 32 to obtain the relationship between the radius of the center hole 31 and the angle of the annular arc surface 32. In actual application scenarios, the larger the radius of the center hole 31, the larger the angle of the annular arc surface 32 will be in order to ensure the actual pressing force of the pressure head, that is, to ensure the contact area between the annular arc surface 32 and the bowl-shaped plug 4.

[0087] R2 is the radius of the circular arc projection of the annular arc surface 32 in the transverse direction of the center hole 31, hereinafter referred to as the radius of the annular arc surface 32; R4 is the radius of the circular arc projection of the bowl-shaped plug 4 in the transverse direction of the center hole 31, hereinafter referred to as the radius of the bowl-shaped plug 4.

[0088] Combination Figure 8 As shown, in some embodiments, the values ​​of the radius of the central hole 31 and the angle of the annular arc surface 32 are selected according to the size of the bowl-shaped plug 4, including steps S41 to S44:

[0089] S41, selecting the radius of the annular arc surface 32 according to the radius of the bowl-shaped plug 4;

[0090] S42, obtaining a relationship between the press-fitting portion 3, the center hole 31 and the annular arc surface 32 according to the radius of the annular arc surface 32;

[0091] S43, selecting the radius of the center hole 31 according to the radius of the press-fitting portion 3;

[0092] S44, obtaining a value of the angle of the annular arc surface 32 according to a relationship among the press-fitting portion 3, the central hole 31 and the annular arc surface 32.

[0093] In this embodiment, first, step S41 selects the radius of the annular arc surface 32 according to the radius of the bowl-shaped plug 4. In a specific embodiment, the radius of the annular arc surface 32 is 1.1 times the radius of the bowl-shaped plug 4.

[0094] Secondly, step S42 obtains the relationship between the press-fitting portion 3, the center hole 31 and the annular arc surface 32 according to the radius of the annular arc surface 32, that is, the press-fitting portion 3 includes the center hole 31 and the annular arc surface 32, and the diameter of the press-fitting portion 3 is the diameter of the center hole 31 plus the length of the projection of the annular arc surface 32 in the direction of the center hole 31. According to the radius of the annular arc surface 32, the relationship between the radius of the press-fitting portion 3, the center hole 31 and the angle of the annular arc surface 32 can be obtained;

[0095] Furthermore, step S43 selects the radius of the center hole 31 according to the radius of the press-fitting portion 3. In a specific embodiment, the radius of the center hole 31 is half of the radius of the press-fitting portion 3.

[0096] Finally, in step S44 , the value of the angle of the annular arc surface 32 can be obtained according to the relationship between the radius of the press-fitting portion 3 , the center hole 31 and the angle of the annular arc surface 32 .

[0097] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A pressing head, used for connecting to a press to press a bowl-shaped plug, characterized in that: include: Indenter body; A connecting portion, the connecting portion being arranged at one end of the pressing head body and being used for connecting to a pressing machine; A press-fitting portion, which is arranged at the other end of the press head body and is used for press-fitting a bowl-shaped plug; The press-fitting portion includes a center hole and an annular arc surface. The center hole is arranged at the center of the press-fitting portion along the press-fitting direction of the bowl-shaped plug, and the inner side of the annular arc surface surrounds the outside of the center hole.

2. The pressure head according to claim 1, characterized in that The press-fitting portion further includes an annular fillet, the inner side of the annular fillet is connected to the outer side of the annular arc surface, and the outer side of the annular fillet is connected to the outer side wall of the press-fitting portion.

3. The pressure head according to claim 2, characterized in that: The radius of the arc projection of the annular curved surface in the transverse direction of the center hole is greater than the radius of the arc projection of the bowl-shaped plug in the transverse direction of the center hole; the radius of the arc projection of the annular fillet in the transverse direction of the center hole is smaller than the radius of the arc projection of the bowl-shaped plug in the transverse direction of the center hole.

4. The pressure head according to claim 1, characterized in that The press-fitting portion is cylindrical, and the radius of the center hole is half of the radius of the press-fitting portion.

5. The pressure head according to claim 1, characterized in that: The connecting portion comprises a connecting hole, and the connecting hole penetrates the pressing head body along the pressing direction of the bowl-shaped plug and is connected to the central hole.

6. A method for designing a pressure head, characterized in that: include: Obtain the required pressing force for the bowl-shaped plug according to the press-in force formula for interference fit; The required pressing force is introduced into the actual pressing force formula of the pressing head, and the area relationship between the center hole and the annular arc surface is obtained; According to the area calculation formula of the center hole, the area calculation formula of the annular arc surface, and the area relationship between the center hole and the annular arc surface, the relationship between the radius of the center hole and the angle of the annular arc surface is obtained; The values ​​of the radius of the center hole and the angle of the annular arc surface are selected according to the relationship between the radius of the center hole and the angle of the annular arc surface and the size of the bowl-shaped plug.

7. The method for designing a pressure head according to claim 6, characterized in that: The method of obtaining the required pressing force for pressing the bowl-shaped plug according to the interference fit pressing force formula includes: The pressing force ΔP required for pressing the bowl-shaped plug into the x =P1*2π*R1*L1*f+Δε; Among them, P1 is the contact stress exerted on the bowl-shaped plug when it is pressed into the press-fitting hole, R1 is the radius of the center hole, L1 is the length of the bowl-shaped plug pressed into the press-fitting hole, f is the friction between the bowl-shaped plug and the press-fitting hole, and Δε is the error value, which depends on the cylindricity, radius and roughness of the press-fitting hole.

8. The method for designing a pressure head according to claim 7, characterized in that: The method of introducing the required pressing force into the actual pressing force formula of the pressing head and obtaining the area relationship between the center hole and the annular arc surface includes: According to the actual pressing force ΔP of the pressing head 实 =(ΔS1-ΔS2)*P1*f=ΔP x Obtaining the area relationship between the center hole and the annular arc surface; Wherein, ΔS1 is the area of ​​the annular arc surface, and ΔS2 is the area of ​​the central hole.

9. The method for designing a pressure head according to claim 8, characterized in that: The step of obtaining the relationship between the radius of the center hole and the angle of the annular arc surface according to the area calculation formula of the center hole, the area calculation formula of the annular arc surface, and the area relationship between the center hole and the annular arc surface includes: The area of ​​the central hole ΔS2 = π*R1 2 ; The area of ​​the annular arc surface ΔS1=(ɑ / 360°)*π*R2; Wherein, ɑ is the angle of the annular arc surface, and R2 is the radius of the arc projection of the annular arc surface in the transverse direction of the center hole.

10. The method for designing a pressure head according to claim 9, characterized in that: The value of the radius of the center hole and the angle of the annular arc surface is selected according to the relationship between the radius of the center hole and the angle of the annular arc surface and the size of the bowl-shaped plug, including: The radius of the annular arc surface is selected according to the radius of the bowl-shaped plug; Obtaining a relationship between the press-fit portion, the center hole, and the annular arc surface according to the radius of the annular arc surface; Selecting the radius of the center hole according to the radius of the press-fitting portion; The value of the angle of the annular arc surface is obtained according to a relationship between the press-fitting portion, the center hole and the annular arc surface.

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