Air tightness detection device and air tightness detection method for cylinder cover

Abstract

The invention belongs to the technical field of airtightness detection, and discloses an airtightness detection device and a cylinder cover airtightness detection method.The cylinder cover is provided with a bolt hole penetrating from a first end face of the cylinder cover to a second end face of the cylinder cover, and the device is used for detecting the bolt hole and comprises a detection bolt, a sealing head, a first sealing ring and a second sealing ring. The detection bolt comprises a head part and a shaft part, the head part is arranged at the first end of the shaft part, the shaft part is used for penetrating through the bolt hole, the second end of the shaft part extends out of the bolt hole, an air gap is formed between the shaft part and the bolt hole, a first air hole extending to the shaft part is formed in the end of the head part, and a second air hole communicated with the first air hole is formed in the peripheral wall of the shaft part. The second end of the shaft part is sleeved with the sealing head, the two ends of the first sealing ring abut against the head part and the first end face respectively, and the two ends of the second sealing ring abut against the sealing head and the second end face respectively. The method is applied to the device. The air tightness detection device is simple in structure, and can detect whether the inner wall of the bolt hole of the cylinder cover has casting defects when being applied to the cylinder cover.

Description

Technical Field

[0001] The present invention relates to the technical field of airtightness detection, and particularly to an airtightness detection device and a method for detecting the airtightness of a cylinder head. Background Art

[0002] The blank of the engine cylinder head is produced by casting technology. The structure of the cylinder head blank is complex and has structures such as air passages, water passages, and oil passages inside. Due to the particularity of the casting process and the complexity of the cylinder head structure, the obtained casting blanks often have defects such as cracks and microshrinkage pores. These defects will cause the tube cavities such as the water passages, air passages, and oil passages opened on the cylinder head to communicate with the inner wall of the bolt holes on the cylinder head, that is, the overall cylinder head has an airtightness defect. If not discovered in time, during the operation of the engine, the lubricating oil in the bolt holes may enter the above-mentioned tube cavities through the above-mentioned communicating parts such as cracks and microshrinkage pores, and the cooling water or gas injected into the water passages and air passages in the above-mentioned tube cavities will leak to the bolt hole part, which will cause engine operation failures and affect the reliability and stability of engine operation. Summary of the Invention

[0003] The purpose of the present invention is to provide an airtightness detection device with a simple structure, which can quickly and reliably detect whether there are casting defects on the inner wall of the bolt holes of the engine cylinder head.

[0004] To achieve this purpose, the present invention adopts the following technical solutions:

[0005] An airtightness detection device for detecting the airtightness of the bolt holes opened on the cylinder head. The cylinder head has a first end face and a second end face arranged oppositely, and the bolt holes penetrate from the first end face to the second end face. The airtightness detection device includes:

[0006] A detection bolt, including a head and a shaft. The head is arranged at the first end of the shaft, the shaft is used to penetrate the bolt hole, and the second end of the shaft extends out of the bolt hole. An air gap is formed between the shaft and the bolt hole. A first air hole extending to the shaft is opened at the end of the head, and a second air hole communicating with the first air hole is opened on the outer peripheral wall of the shaft;

[0007] A sealing head, sleeved on the second end of the shaft;

[0008] A first sealing ring, sleeved on the first end of the shaft. One end of the first sealing ring abuts tightly against the head, and the other end abuts tightly against the first end face;

[0009] A second sealing ring, sleeved on the second end of the shaft. One end of the second sealing ring abuts tightly against the sealing head, and the other end abuts tightly against the second end face.

[0010] Preferably, the sealing head is provided with a docking hole, the second end of the shaft portion is provided with an external thread, and the inner wall of the docking hole is correspondingly provided with an internal thread, and the second end of the shaft portion is threadedly connected to the docking hole.

[0011] Preferably, the first air hole is opened along the axial direction of the shaft portion, and the second air hole is opened along the radial direction of the shaft portion.

[0012] Preferably, the diameter of the first air hole and the diameter of the second air hole are set to be 1 / 3 - 1 / 5 of the diameter of the shaft portion.

[0013] Preferably, the detection bolt further includes a first shoulder. Along the axial direction of the detection bolt, the head, the first shoulder, and the first end of the shaft portion are arranged in sequence. The diameter of the first shoulder is greater than the diameter of the head, the diameter of the head is greater than the diameter of the shaft portion, and one end of the first sealing ring abuts tightly against the first shoulder, and the other end abuts tightly against the first end face.

[0014] Preferably, the head, the first shoulder, and the shaft portion are integrally formed.

[0015] Preferably, the inner peripheral wall of the first air hole is provided with an internal thread for screwing with a quick-change joint of an air pipe.

[0016] Preferably, both the head and the sealing head are provided in a hexagonal shape.

[0017] Preferably, the materials of the first sealing ring and the second sealing ring are both set to rubber.

[0018] The present invention also provides a method for detecting the airtightness of a cylinder head, which can quickly and reliably detect whether there are casting defects on the inner wall of the bolt hole of the engine cylinder head.

[0019] A method for detecting the airtightness of a cylinder head, which applies the above-mentioned airtightness detection device, and the method for detecting the airtightness of the cylinder head includes the following steps:

[0020] S100. After sleeving a first sealing ring on the first end of the shaft portion, pass through the bolt hole of the cylinder head to be detected, so that the second end of the shaft portion extends out of the bolt hole and then sleeving a second sealing ring, and install the sealing head, so that one end of the first sealing ring abuts tightly against the head, and the other end abuts tightly against the first end face, and one end of the second sealing ring abuts tightly against the sealing head, and the other end abuts tightly against the second end face;

[0021] S200. Connect the quick-change joint of the air pipe to the head, the air pipe is communicated with an air source, and the gas provided by the air source sequentially passes through the air pipe, the first air hole, and the second air hole and is introduced into the air gap;

[0022] S300. Immerse the cylinder head as a whole into the leak detection liquid and observe whether bubbles are generated in the leak detection liquid;

[0023] If the observation result is yes, there are casting defects on the inner wall of the bolt hole, and the airtightness does not meet the requirements;

[0024] If the observation result is no, there are no casting defects on the inner wall of the bolt hole, and the airtightness meets the requirements.

[0025] Beneficial effects:

[0026] When the airtightness detection device provided by the present invention is in use, the first end of the shaft part is sleeved with a first sealing ring and then passes through the bolt hole of the cylinder head to be detected, so that the second end of the shaft part extends out of the bolt hole and is sleeved with a second sealing ring, and a sealing head is installed, so that one end of the first sealing ring tightly abuts against the head, and the other end tightly abuts against the first end face, and one end of the second sealing ring tightly abuts against the sealing head, and the other end tightly abuts against the second end face. Under the tight abutting action of the head and the first end face, the first sealing ring can reliably and effectively block the outer edge of one end of the bolt hole facing the first end face. Under the tight abutting action of the sealing head and the second end face, the second sealing ring can reliably and effectively block the outer edge of one end of the bolt hole facing the second end face, so as to reliably and effectively seal both ends of the bolt hole, so that gas cannot leak out from both ends of the bolt hole. Subsequently, a quick-change joint for connecting an air pipe is connected to the head, the air pipe is communicated with an air source, and the gas provided by the air source sequentially passes through the air pipe, the first air hole, and the second air hole and enters the air gap. The air gap is specifically the gap between the outer peripheral arm of the shaft part and the inner peripheral arm of the bolt hole. Under the action of the first sealing ring and the second sealing ring, both ends of the air gap are blocked. At this time, the gas supplied by the air source fills the entire air gap. Next, immerse the cylinder head as a whole into the leak detection liquid and observe whether bubbles are generated in the leak detection liquid. If the observation result is yes, it indicates that there is a communication phenomenon between the inner wall of the bolt hole and the pipe cavities such as the water channel, air channel, and oil channel opened in the cylinder head, that is, there are communication parts such as cracks and microshrinkage holes between the inner wall of the bolt hole and the pipe cavities such as the water channel, air channel, and oil channel opened in the cylinder head, so that the gas in the air gap will enter the water channel, air channel, oil channel and other pipe cavities through the above-mentioned cracks, microshrinkage holes and other communication parts, and finally be discharged into the leak detection liquid and form bubbles, then there are casting defects on the inner wall of the bolt hole, and the airtightness does not meet the requirements; it indicates that the inner wall of the bolt hole is not communicated with the pipe cavities such as the water channel, air channel, and oil channel opened in the cylinder head, and the gas in the air gap will not enter the water channel, air channel, oil channel and other pipe cavities, so it will not be discharged into the leak detection liquid and generate bubbles, then there are no casting defects on the inner wall of the bolt hole, and the airtightness meets the requirements. This airtightness detection device has a simple structure. Applying the corresponding airtightness detection method of the cylinder head to the airtightness detection device can quickly and reliably detect whether there are casting defects on the inner wall of the bolt hole of the engine cylinder head. Description of the Drawings

[0027] Figure 1It is a schematic structural diagram of the airtightness detection device provided by the present invention assembled with the cylinder head;

[0028] Figure 2 It is the present invention in Figure 1 The schematic cross-sectional view in the A direction;

[0029] Figure 3 It is a schematic structural diagram of the detection bolt provided by the present invention;

[0030] Figure 4 It is the present invention in Figure 3 The schematic cross-sectional view in the B direction;

[0031] Figure 5 It is a schematic structural diagram of the sealing head provided by the present invention;

[0032] Figure 6 It is the present invention in Figure 5 The schematic cross-sectional view in the C direction;

[0033] Figure 7 It is a schematic structural diagram of the first sealing ring and the second sealing ring provided by the present invention;

[0034] Figure 8 It is a schematic flow chart of the cylinder head airtightness detection method provided by the present invention.

[0035] In the figure:

[0036] 1. Detection bolt; 11. Head; 111. First air hole; 12. Shaft part; 121. Second air hole; 13. First shoulder;

[0037] 2. Sealing head; 21. Docking hole;

[0038] 3. First sealing ring;

[0039] 4. Second sealing ring;

[0040] 5. Cylinder head; 501. First end face; 502. Second end face; 51. Bolt hole. Detailed implementation manners

[0041] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention are shown in the drawings, rather than all structures.

[0042] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral body; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include direct contact between the first and second features, or may include the first and second features not being in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "under", and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0044] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0045] This embodiment provides an airtightness detection device. Refer to Figures 1 to 7As shown in the figure, the airtightness detection device is used to detect the airtightness of the bolt holes 51 formed in the cylinder head 5. The cylinder head 5 has a first end face 501 and a second end face 502 arranged opposite to each other, and the bolt holes 51 penetrate from the first end face 501 to the second end face 502. The airtightness detection device includes a detection bolt 1, a sealing head 2, a first sealing ring 3 and a second sealing ring 4. The detection bolt 1 includes a head 11 and a shaft portion 12. The head 11 is arranged at the first end of the shaft portion 12. The shaft portion 12 is used to penetrate the bolt hole 51, and the second end of the shaft portion 12 extends out of the bolt hole 51. An air gap is formed between the shaft portion 12 and the bolt hole 51. A first air hole 111 extending to the shaft portion 12 is formed at the end of the head 11, and a second air hole 121 communicating with the first air hole 111 is formed on the outer peripheral wall of the shaft portion 12; the sealing head 2 is sleeved on the second end of the shaft portion 12; the first sealing ring 3 is sleeved on the first end of the shaft portion 12. One end of the first sealing ring 3 abuts tightly against the head 11, and the other end abuts tightly against the first end face 501; the second sealing ring 4 is sleeved on the second end of the shaft portion 12. One end of the second sealing ring 4 abuts tightly against the sealing head 2, and the other end abuts tightly against the second end face 502.

[0046] This embodiment also provides a method for detecting the airtightness of the cylinder head 5. The method for detecting the airtightness of the cylinder head 5 uses the above-mentioned airtightness detection device. The following describes the use process and beneficial effects of the above-mentioned airtightness detection device in conjunction with the method.

[0047] Refer to Figure 8 As shown in the figure, the method for detecting the airtightness of the cylinder head 5 includes the following steps:

[0048] S100. After sleeving the first sealing ring 3 on the first end of the shaft portion 12, the shaft portion 12 penetrates the bolt hole 51 of the cylinder head 5 to be detected, so that the second end of the shaft portion 12 extends out of the bolt hole 51 and then sleeving the second sealing ring 4, and installing the sealing head 2, so that one end of the first sealing ring 3 abuts tightly against the head 11, the other end abuts tightly against the first end face 501, and one end of the second sealing ring 4 abuts tightly against the sealing head 2, and the other end abuts tightly against the second end face 502;

[0049] S200. The head 11 is connected to the quick-change joint of the air pipe, the air pipe is connected to the air source, and the gas provided by the air source is sequentially introduced into the air gap through the air pipe, the first air hole 111 and the second air hole 121;

[0050] S300. The whole cylinder head 5 is immersed in the leak detection liquid, and observe whether bubbles are generated in the leak detection liquid;

[0051] If the observation result is yes, there are casting defects on the inner wall of the bolt hole 51, and the airtightness does not meet the requirements;

[0052] If the observation result is no, there are no casting defects on the inner wall of the bolt hole 51, and the airtightness meets the requirements.

[0053] Specifically, when the airtightness detection device is in use, the first end of the shaft portion 12 is sleeved with a first sealing ring 3 and then passes through the bolt hole 51 of the cylinder head 5 to be detected, so that the second end of the shaft portion 12 extends out of the bolt hole 51 and is sleeved with a second sealing ring 4, and the sealing head 2 is installed, so that one end of the first sealing ring 3 abuts against the head portion 11, and the other end abuts against the first end face 501, and one end of the second sealing ring 4 abuts against the sealing head 2, and the other end abuts against the second end face 502. Under the abutting action of the first sealing ring 3 between the head portion 11 and the first end face 501, the outer edge of one end of the bolt hole 51 facing the first end face 501 can be reliably and effectively blocked. Under the abutting action of the second sealing ring 4 between the sealing head 2 and the second end face 502, the outer edge of one end of the bolt hole 51 facing the second end face 502 can be reliably and effectively blocked, so as to reliably and effectively seal both ends of the bolt hole 51, so that gas cannot leak out from both ends of the bolt hole 51. Subsequently, a quick-change joint for connecting a gas pipe is connected to the head portion 11, the gas pipe is communicated with a gas source, and the gas provided by the gas source is sequentially introduced into the air gap through the gas pipe, the first air hole 111, and the second air hole 121. The air gap is specifically the gap between the outer peripheral arm of the shaft portion 12 and the inner peripheral arm of the bolt hole 51. Under the action of the first sealing ring 3 and the second sealing ring 4, both ends of the air gap are blocked. At this time, the gas supplied by the gas source fills the entire air gap. Next, the entire cylinder head 5 is immersed in the leak detection liquid, and it is observed whether bubbles are generated in the leak detection liquid. If the observation result is yes, it indicates that there is a communication phenomenon between the inner wall of the bolt hole 51 and the pipe cavities such as the water channel, air channel, and oil channel opened in the cylinder head 5, that is, there are communication parts such as cracks and micro-shrinkage holes between the inner wall of the bolt hole 51 and the pipe cavities such as the water channel, air channel, and oil channel opened in the cylinder head 5, so that the gas in the air gap will enter the water channel, air channel, oil channel and other pipe cavities through the above-mentioned cracks, micro-shrinkage holes and other communication parts, and finally be discharged into the leak detection liquid and form bubbles, then there are casting defects on the inner wall of the bolt hole 51, and the airtightness does not meet the requirements; it indicates that the inner wall of the bolt hole 51 is not communicated with the pipe cavities such as the water channel, air channel, and oil channel opened in the cylinder head 5, and the gas in the air gap will not enter the water channel, air channel, oil channel and other pipe cavities, so it will not be discharged into the leak detection liquid and generate bubbles, then there are no casting defects on the inner wall of the bolt hole 51, and the airtightness meets the requirements. This airtightness detection device has a simple structure. Applying the corresponding airtightness detection method of the cylinder head 5 to the airtightness detection device can quickly and reliably detect whether there are casting defects on the inner wall of the bolt hole 51 of the engine cylinder head 5.

[0054] Specifically, the gas supplied by the gas source is compressed gas. The compressed gas passes through the gas pipe and then passes through the ball valve and the pressure control valve and is connected to the head portion 11 and communicated with the first air hole 111. The adjustment pressure of the pressure control valve is adjusted to 0.3 - 0.5 MPa.

[0055] In this embodiment, the sealing head 2 is provided with a docking hole 21. The second end of the shaft portion 12 is provided with an external thread, and the inner wall of the docking hole 21 is correspondingly provided with an internal thread. The second end of the shaft portion 12 is threadedly connected to the docking hole 21. Specifically, the sealing head 2 and the second end of the shaft portion 12 are fixed by screwing, thereby realizing reliable and effective pressing against the first sealing ring 3 and the second sealing ring 4, and realizing effective sealing at both ends of the bolt hole 51. Optionally, when the sealing ring is screwed with the shaft portion 12, it is screwed and tightened with a tightening force of 40-50 N·m.

[0056] Specifically, the thread depth dimension of the docking hole 21 is b4, and the total length of the docking hole 21 is b5. b4 needs to be greater than the difference between the length dimensions of the shaft portion 12 and the bolt hole 51.

[0057] Specifically, along the axial direction of the inspection screw, the length of the shaft portion 12 is a1, and the length of the external thread on the shaft portion 12 is a2. The difference between a1 and a2 needs to be less than the length dimension of the bolt hole 51 of the cylinder head 5.

[0058] In this embodiment, both the head 11 and the sealing head 2 are set to be hexagonal. With such a setting, it is convenient for operating tools such as wrenches to perform screwing operations. Specifically, along the radial direction of the inspection bolt 1, the hexagonal dimension of the head 11 is a3; along the radial direction of the seal, the hexagonal dimension on the seal is b1.

[0059] In this embodiment, the first air hole 111 is opened along the axial direction of the shaft portion 12, and the second air hole 121 is opened along the radial direction of the shaft portion 12. Optionally, the number of the second air holes 121 can be set to be multiple, so as to be able to uniformly and comprehensively deliver gas to the inner peripheral wall of the bolt hole 51.

[0060] In this embodiment, the diameters of the first air hole 111 and the second air hole 121 are set to be 1 / 5-1 / 3 of the diameter of the shaft portion 12. Specifically, the diameters of the first air hole 111 and the second air hole 121 are a9, and the diameter of the shaft portion 12 is a5, 1 / 5a5<a9<1 / 3a3. With such a setting, it not only ensures the effective passage of gas, but also ensures the reliable strength of the overall inspection bolt 1. Specifically, the aperture dimension of the docking hole 21 is b6, and b6 is equal to a5. In addition, the length dimension of the sealing head 2 is b7, and b7 is greater than b5, that is, the docking hole 21 is not set as a through hole.

[0061] In this embodiment, the detection bolt 1 further includes a first shoulder 13. Along the axial direction of the detection bolt 1, the head 11, the first shoulder 13, and the first end of the shaft portion 12 are arranged in sequence. The diameter of the first shoulder 13 is greater than that of the head 11, and the diameter of the head 11 is greater than that of the shaft portion 12. One end of the first sealing ring 3 abuts tightly against the first shoulder 13, and the other end abuts tightly against the first end face 501. Specifically, the diameter dimension of the first shoulder 13 is a4, and the diameter dimension of the first shoulder 13 is equal to the diameter dimension c3 of the first sealing ring 3. The inner hole diameter dimension of the first sealing ring 3 is c2, and c2 is equal to a5. Specifically, the thickness dimension of the first shoulder 13 is a8.

[0062] In this embodiment, the head 11, the first shoulder 13, and the shaft portion 12 are integrally formed. Since the overall structure of the detection screw is relatively simple, the integral forming is convenient for processing and avoids the process of split assembly.

[0063] In this embodiment, the size parameters of the second sealing ring 4 and the first sealing ring 3 are set to be equal.

[0064] Specifically, along the axial direction of the detection bolt 1, the depth of the first air hole 111 is a6, the positioning dimension between the second air hole 121 and the first shoulder 13 is a7, and a6 is greater than a7. The thickness dimension of the first sealing ring 3 is c1, and c1 is less than a7.

[0065] In this embodiment, a second shoulder is integrally provided on the side of the sealing head 2 facing the shaft portion 12. The diameter of the second shoulder is greater than that of the sealing head 2. One end of the second sealing ring 4 abuts tightly against the second shoulder, and the other end abuts tightly against the second end face 502. Specifically, the diameter dimension of the second shoulder is b2, and the thickness dimension of the second shoulder is b3.

[0066] In this embodiment, an internal thread for screwing with a quick-change joint of the air pipe is provided on the inner peripheral wall of the first air hole 111. The first air hole 111 and the quick-change joint of the air pipe can be fixed reliably and effectively.

[0067] In this embodiment, the materials of the first sealing ring 3 and the second sealing ring 4 are both set to rubber. The rubber material has low cost, is convenient to prepare, and also has an effective sealing effect.

[0068] In this embodiment, the materials of the detection bolt 1 and the sealing head 2 can be considered to be performance materials of 45 steel and above.

[0069] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. An air tightness detection device for detecting the air tightness of a bolt hole (51) provided in a cylinder head (5), wherein the cylinder head (5) has a first end face (501) and a second end face (502) arranged opposite to each other, and the bolt hole (51) passes through from the first end face (501) to the second end face (502), characterized in that: The airtightness detection device comprises: A detection bolt (1) comprises a head (11) and a shaft (12), wherein the head (11) is arranged at a first end of the shaft (12), the shaft (12) is used to penetrate the bolt hole (51), and the second end of the shaft (12) extends out of the bolt hole (51), an air gap is formed between the shaft (12) and the bolt hole (51), a first air hole (111) extending to the shaft (12) is formed at an end of the head (11), and a second air hole (121) connected to the first air hole (111) is formed on an outer peripheral wall of the shaft (12); A sealing head (2) sleeved on the second end of the shaft portion (12); A first sealing ring (3) is sleeved on the first end of the shaft portion (12), one end of the first sealing ring (3) is tightly against the head portion (11), and the other end is tightly against the first end surface (501); The second sealing ring (4) is sleeved on the second end of the shaft portion (12); one end of the second sealing ring (4) is tightly against the sealing head (2), and the other end is tightly against the second end surface (502).

2. The airtightness detection device according to claim 1, characterized in that: The sealing head (2) is provided with a docking hole (21), the second end of the shaft portion (12) is provided with an external thread, the inner wall of the docking hole (21) is correspondingly provided with an internal thread, and the second end of the shaft portion (12) is threadedly connected to the docking hole (21).

3. The airtightness detection device according to claim 1, characterized in that: The first air hole (111) is opened along the axial direction of the shaft portion (12), and the second air hole (121) is opened along the radial direction of the shaft portion (12).

4. The airtightness detection device according to claim 1, characterized in that: The diameter of the first air hole (111) and the diameter of the second air hole (121) are set to 1 / 3-1 / 5 of the diameter of the shaft portion (12).

5. The airtightness detection device according to claim 1, characterized in that: The detection bolt (1) also includes a first shoulder (13). Along the axial direction of the detection bolt (1), the head (11), the first shoulder (13) and the first end of the shaft (12) are arranged in sequence, the diameter of the first shoulder (13) is greater than the diameter of the head (11), and the diameter of the head (11) is greater than the diameter of the shaft (12). One end of the first sealing ring (3) is tightly against the first shoulder (13), and the other end is tightly against the first end surface (501).

6. The airtightness detection device according to claim 5, characterized in that: The head portion (11), the first shoulder portion (13) and the shaft portion (12) are integrally formed.

7. The airtightness detection device according to claim 1, characterized in that: The inner peripheral wall of the first air hole (111) is provided with an internal thread for threaded connection with a quick-change joint of an air pipe.

8. The airtightness detection device according to claim 1, characterized in that: The head (11) and the sealing head (2) are both configured in a hexagonal shape.

9. The airtightness detection device according to claim 1, characterized in that: The material of the first sealing ring (3) and the second sealing ring (4) is both set to be rubber.

10. A cylinder head air tightness detection method, characterized in that: Using the air tightness detection device according to any one of claims 1 to 9, the cylinder head air tightness detection method comprises the following steps: S100, after the first end of the shaft portion (12) is sleeved with a first sealing ring (3), the bolt hole (51) of the cylinder head (5) to be inspected is penetrated, so that the second end of the shaft portion (12) extends out of the bolt hole (51), and then the second sealing ring (4) is sleeved, and the sealing head (2) is installed, so that one end of the first sealing ring (3) is tightly against the head (11), and the other end is tightly against the first end surface (501), and one end of the second sealing ring (4) is tightly against the sealing head (2), and the other end is tightly against the second end surface (502); S200, the head (11) is connected to a quick-change joint of an air pipe, the air pipe is connected to an air source, and the air source provides gas that is sequentially passed through the air pipe, the first air hole (111), and the second air hole (121) into the air gap; S300, immersing the entire cylinder head (5) in a leak test liquid, and observing whether bubbles are generated in the leak test liquid; If the observation result is yes, then there is a casting defect in the inner wall of the bolt hole (51), and the air tightness does not meet the requirements; If the observation result is no, then there is no casting defect on the inner wall of the bolt hole (51), and the air tightness meets the requirements.

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