A helium leak detection fixture for a VVT gear and a method for detecting the airtightness of a VVT gear

Abstract

The present invention discloses a helium leak detection fixture for a VVT gear, which includes a base and a leak detection tooling. A cover body for accommodating the leak detection tooling is provided on the base, and the leak detection tooling forms a vacuum environment through the cover body. The leak detection tooling includes a tooling base plate and a fixture body provided on the tooling base plate and used for carrying the VVT gear. A first boss extending upward is provided in the middle of the fixture body. A cover is fixed to the top of the cover body, and the bottom center of the cover is docked with the top of the VVT gear through a downward pressing assembly. An air hole distributed in the vertical direction is provided in the center of the downward pressing assembly. The top of the cover is driven by a linear movement mechanism to move the cover body up and down. A sealing ring is fixed to the bottom of the cover body, and a groove matching the sealing ring is provided on the base. An air extraction hole is provided on the base, and the air extraction hole is connected to a helium leak detector. The present invention enables the airtightness detection of the VVT gear to be conveniently detected by a helium leak detector, thus greatly improving the accuracy and efficiency of the airtightness detection.

Description

Technical Field

[0001] The present invention relates to an airtightness detection technology, and particularly to a helium leak detection fixture for a VVT gear and an airtightness detection method for the VVT gear. Background Art

[0002] The VVT (Variable Valve Timing) system adjusts the phase of the engine cam through the equipped control machine execution system, so that the opening and closing times of the valves change with the engine speed, in order to improve the charging efficiency and increase the engine power. The phase change of the cam mainly depends on the camshaft connected thereto, and the camshaft realizes the change through the VVT gear connected thereto. If the camshaft wants to change, hydraulic oil needs to enter the oil passage in the VVT gear to form an oil pressure, which exerts pressure on the positioning pin inside the VVT gear, so that it no longer fits into the locking hole. Then the camshaft can start to rotate. In the state without oil pressure, the positioning pin fits into the locking hole by the elastic force of the spring, and the camshaft will not rotate relative to the VVT gear. The sealing performance of the VVT gear directly affects the power and stability of the engine. However, at present, most of the airtightness detections of the VVT gear are carried out by the water-tight method, which is time-consuming, laborious, and has low detection accuracy. Summary of the Invention

[0003] In order to solve the above deficiencies in the prior art, the purpose of the present invention is to provide a helium leak detection fixture for a VVT gear and an airtightness detection method for the VVT gear. The helium leak detection fixture for the VVT gear can make the airtightness detection work of the VVT gear convenient for detection by a helium leak detector, thus greatly improving the accuracy and efficiency of the airtightness detection.

[0004] The technical solution adopted by the present invention to solve its technical problems is as follows: A helium leak detection fixture for a VVT gear, including a base and a leak detection tooling. A cover body for accommodating the leak detection tooling is provided on the base. The leak detection tooling is installed inside the cover body and forms a vacuum environment through the cover body;

[0005] The leak detection tooling includes a tooling bottom plate and a fixture body provided on the tooling bottom plate and used for carrying the VVT gear. A first boss extending upward is provided in the middle of the fixture body. The bottom end face of the VVT gear is placed on the first boss and is sealed with the first boss;

[0006] A cover is fixed at the top of the cover body. The bottom center of the cover is docked with the top of the VVT gear through a downward pressing component. An air hole distributed in the vertical direction is provided at the center of the downward pressing component. After the downward pressing component is docked with the VVT gear, one end of the air hole is docked with the shaft hole located at the center of the VVT gear, and the other end of the air hole is connected with a helium leak detection inflation component;

[0007] The top of the cover drives the cover body to move up and down through a linear motion mechanism. A sealing ring is fixed at the bottom of the cover body, and a groove matching the sealing ring is provided on the base;

[0008] An air extraction hole is provided on the base, and the air extraction hole is connected to a helium leak detector.

[0009] Optionally, the tooling bottom plate is connected to the base through a plurality of guide posts. The tooling bottom plate moves up and down along the guide posts, and the guide posts are fixedly installed on the top surface of the base.

[0010] Optionally, the pressing component includes a pressing head fixedly installed at the center of the bottom of the cover. A sealing pressing cover is provided below the pressing head. The sealing pressing cover overlaps the top end of the VVT gear and seals with the top end of the VVT gear;

[0011] The air holes include a first air hole and a second air hole. The first air hole is provided in the pressing head and is arranged along the axis of the pressing head. The second air hole is provided in the sealing pressing cover and is arranged along the axis of the sealing pressing cover. The first air hole and the second air hole are coaxially arranged, and the first air hole and the second air hole are hermetically butted.

[0012] Optionally, the first air hole in the pressing head is connected to a helium leak detection inflation component through an inflation flange. The pressing head is fixedly installed on the bottom end face of the inflation flange. The inflation flange is fixedly installed in the middle of the cover. The bottom of the inflation interface of the inflation flange is hermetically butted with the first air hole.

[0013] Optionally, a concave portion is further provided on the top surface of the first boss, and a filling block with a convex cross-section is placed in the concave portion. There is a gap between the filling block and the concave portion.

[0014] Optionally, a spring is further provided between the tooling bottom plate and the base.

[0015] With the above technical solution, the present invention forms a vacuum state in the external environment of the leak detection tooling through the cover body that can move up and down, in cooperation with a helium leak detector, and then helium gas is introduced into the VVT gear through the air holes. The helium leak situation of the VVT gear is detected by the helium leak detector, so as to detect the leakage rate of the entire VVT gear. The leak detection tooling adopted by the present invention can not only quickly clamp the VVT gear, but also has a tight fit, and can improve the accuracy of the airtightness detection of the VVT.

[0016] The present invention also provides a method for detecting the airtightness of a VVT gear, including the following steps:

[0017] Install the VVT gear on the VVT gear helium leak detection fixture;

[0018] The surrounding environment of the VVT gear helium leak detection fixture is evacuated to a vacuum state by a helium leak detector;

[0019] Helium gas is filled into the VVT gear;

[0020] The helium leak detector is used to detect the leakage rate of the oil holes of the VVT gear;

[0021] After the leakage rate detection is completed, the VVT gear is taken out from the VVT gear helium leak detection fixture;

[0022] Wherein, the VVT gear helium leak detection fixture includes a base and a leak detection tooling. A cover body for accommodating the leak detection tooling is provided on the base. The leak detection tooling is installed inside the cover body, and a vacuum environment is formed through the cover body;

[0023] The leak detection tooling includes a tooling bottom plate and a fixture body provided on the tooling bottom plate and used for carrying the VVT gear. A convex platform extending upward is provided in the middle of the fixture body. The bottom end face of the VVT gear is placed on the first convex platform and sealed with the first convex platform;

[0024] A cover is fixed at the top of the cover body. The center bottom of the cover is docked with the top of the VVT gear through a downward pressing component. An air hole distributed in the vertical direction is provided in the center of the downward pressing component. After the downward pressing component is docked with the VVT gear, one end of the air hole is docked with the shaft hole located in the center of the VVT gear, and the other end of the air hole is connected to a helium leak detection inflation component;

[0025] The top of the cover drives the cover body to move up and down through a linear movement mechanism. A sealing ring is fixed at the bottom of the cover body, and a groove matching the sealing ring is provided on the base;

[0026] An air extraction hole is provided on the base, and the air extraction hole is connected to a helium leak detector.

[0027] Optionally, after the VVT gear is detected, the helium gas is first recovered from the VVT gear helium leak detection fixture, and then the VVT gear is taken out from the VVT gear helium leak detection fixture.

[0028] Adopting the above technical solution, the airtightness detection method of the VVT gear of the present invention uses the above leak detection tooling to clamp the VVT gear, which not only ensures the tightness of the detection environment, but also realizes the rapid clamping of the VVT gear. Compared with the traditional water tightness detection method, the efficiency and accuracy of the airtightness detection of the VVT gear are improved. In addition, by using the detection method of the present invention, the recovery of helium gas can also be realized, reducing the difficulty of helium gas recovery and avoiding the waste of helium gas. Brief Description of the Drawings

[0029] Figure 1 is a schematic structural diagram of the present invention;

[0030] Figure 2 is Figure 1 a sectional perspective view of

[0031] Figure 3 is Figure 2 the front view of

[0032] Figure 4 is Figure 3 the enlarged view of part A of

[0033] Figure 5 is the assembly schematic diagram of the VVT gear and the tooling base plate of the present invention. Detailed implementation manners

[0034] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than limiting the invention. In addition, it should be noted that, for the convenience of description, only the parts related to the invention are shown in the drawings.

[0035] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and embodiments.

[0036] As Figures 1 to 5 shown, the present invention discloses a helium leak detection fixture for a VVT gear. This fixture is used for clamping the VVT gear 4 and detecting the air tightness of the VVT gear 4. The fixture includes a base 1 and a leak detection tooling 2. A cover 3 for accommodating the leak detection tooling 2 is provided on the base 1. The leak detection tooling 2 is installed inside the cover 3, and a vacuum environment is formed through the cover 3. This vacuum environment is used for helium leak detection of the VVT gear 4, so as to realize the detection of the air tightness of the oil passage of the VVT gear 4. Therefore, an air extraction hole 14 needs to be provided on the base 1. The air extraction hole 14 is connected to a helium leak detector (not shown in the figure). The helium leak detector evacuates the cover 3 to a vacuum through this air extraction hole 14. Thus, the air extraction hole 14 is located within the area covered by the inside of the cover 3.

[0037] In the present invention, the leak detection tooling 2 is used to clamp the VVT gear 4 inside the cover 3. After the detection of the VVT gear 4, the VVT gear 4 also needs to be taken out from the leak detection tooling 2. Therefore, the clamping of the VVT gear 4 by the leak detection tooling 2 itself needs to ensure both airtightness and detachability. Also, since the leak detection tooling 2 is provided inside the cover 3, that is, when the VVT gear 4 is being detected, the VVT gear 4 is assembled inside the cover 3. Therefore, the vacuum environment between the cover 3 and the base 1 is variable.

[0038] Thus, in this embodiment, as Figure 2 , 3 shown, the leak detection tooling 2 includes a tooling base plate 5 and a fixture 6 provided on the tooling base plate 5 and used to carry the VVT gear 4. A first boss 7 extending upward is provided in the middle of the fixture 6. When the leak detection tooling 2 and the VVT gear 4 are assembled, the bottom end face of the VVT gear 4 is placed on the first boss 7 and sealed with the first boss 7. A cover 8 is fixed to the top of the cover body 3. The cover 8 drives the cover body 3 to move up and down through a linear movement mechanism 11. The bottom center of the cover 8 is docked with the top of the VVT gear 4 through a downward pressing assembly 9. The VVT gear 4 completes the sealed assembly with the leak detection tooling 2 through the downward pressure of the downward pressing assembly 9. In addition, a sealing ring 12 is fixed to the bottom of the cover body 3, and a groove 13 matching the sealing ring 12 is provided on the base 1. When the cover body 3 is driven by the linear movement mechanism 11 to move downward, the sealing ring 12 and the groove 13 are assembled, so as to form a sealed space inside the cover body 3, facilitating the helium leak detector to evacuate the internal space of the cover body 3 into a vacuum.

[0039] In this embodiment, as Figure 4 shown, a concave portion 18 is further provided on the top surface of the first boss 7, and a filling block 19 with a convex cross-section is placed in the concave portion 18. There is a gap between the filling block 19 and the concave portion 18, and the filling block 19 is fixed in the concave portion 18 by screws.

[0040] Specifically, as Figures 2 to 4 shown, an air hole 10 distributed in the vertical direction is provided in the center of the downward pressing assembly 9. After the downward pressing assembly 9 is docked with the VVT gear 4, one end of the air hole 10 is docked with the shaft hole located in the center of the VVT gear 4, and the other end of the air hole 10 is connected to a helium leak detection inflation assembly (not shown in the figure). When detecting the VVT gear 4, helium gas is filled into the air hole 10 through the helium leak detection inflation assembly, and the helium gas then flows into the oil passage of the VVT gear 4 through the air hole 10.

[0041] In order to facilitate the tooling base plate 5 to move linearly, when specifically setting the tooling base plate 5, as Figure 5 shown, the tooling base plate 5 is connected to the base 1 through a plurality of guide posts 15. When the linear movement mechanism 11 drives the cover 8 to move downward, the tooling base plate 5 moves downward along the guide posts 15. When the linear movement mechanism 11 drives the cover 8 to move upward, since the tooling base plate 5 and the downward pressing assembly 9 are separate bodies, a spring 16 can be further provided between the tooling base plate 5 and the base 1, so that after the linear movement mechanism 11 moves upward, the tooling base plate 5 can be reset upward, and under the action of the spring 16, the cooperation between the tooling base plate 5 and the downward pressing assembly 9 is closer, so that the assembly of the VVT gear 4 in the leak detection tooling 2 is tighter, which is beneficial to improving the detection accuracy.

[0042] Specifically, asFigure 3 , 4 As shown in 4 , the pressing component 9 includes a pressing head 901 fixedly installed at the center of the bottom of the cover. Below the pressing head 901, there is a sealing gland 902. During assembly, the sealing gland 902 overlaps the top of the VVT gear 4 and seals with the top of the VVT gear 4. As Figure 4 shown in Figure 4 , a second boss 20 protruding downward is provided in the middle of the bottom of the sealing gland 902. The second boss 20 cooperates with the top of the VVT gear 4, and a sealing sleeve 21 is also sleeved between the outside of the second boss 20 and the top of the VVT gear 4. The sealing sleeve 21 is directly placed between the VVT gear 4 and the second boss 20 to generate a sealing effect under the downward pressure of the pressing component 9.

[0043] As described above, the pressing component 9 is composed of a split structure (the pressing head 901 and the sealing gland 902). Therefore, the air hole 10 also includes two split parts, that is, the air hole 10 includes a first air hole 1001 and a second air hole 1002. Among them, the first air hole 1001 is provided in the pressing head 901 and is arranged along the axis of the pressing head 901. The second air hole 1002 is provided in the sealing gland 902 and is arranged along the axis of the sealing gland 902. The first air hole 1001 and the second air hole 1002 are coaxially arranged, and the first air hole 1001 and the second air hole 1002 are hermetically butted during assembly.

[0044] When connecting with the helium leak detection inflation component, as Figure 1 , 2 shown in Figure 1 and 2 , the first air hole 1001 in the pressing head 901 is connected to the helium leak detection inflation component through an inflation flange 17. As Figure 3 shown in Figure 3 , the pressing head 901 is fixedly installed on the bottom end face of the inflation flange 17. The inflation flange 17 is fixedly installed in the middle of the cover 8. The bottom of the inflation interface of the inflation flange 17 is hermetically butted with the first air hole 1001. When specifically setting the inflation flange 17, as Figure 3 shown in Figure 3 , the inflation flange 17 includes a flange body 1701 and a flange joint 1702. A first stepped hole 1703 is also provided in the flange body 1701 along the axial direction. The top of the first stepped hole 1703 is connected to the flange joint 1702. The bottom end of the first stepped hole 1703 is butted with the first air hole 1001, and internal threads are also provided on the inner wall of the bottom of the first stepped hole 1703. In addition, in this embodiment, a second stepped hole 903 distributed along the axial direction is also provided in the pressing head 901. A fastening screw 904 is provided in the second stepped hole 903. The second stepped hole 903 cooperates with the head of the fastening screw 904, and the tail of the fastening screw 904 cooperates with the internal threads of the first stepped hole 1703, thereby realizing the fastening of the pressing head 901 and the inflation flange 17. Thus, a through hole 905 distributed along the axis needs to be provided inside the screw 904 to ensure the smoothness of the air hole 10.

[0045] In this embodiment, as Figure 1 , 2 shown, the linear movement mechanism 11 includes a driving cylinder (not shown in the figure), a floating joint 1101, a connecting member 1102, and a linear guiding mechanism 1103. As Figure 1 and 2 shown, the connecting member 1102 is composed of four connecting plates, and the four connecting plates are respectively three side plates and one end plate. The linear guiding mechanism 1103 is fixedly installed on the end plate, and the floating joint 1101 is fixedly installed on one of the side plates at the top. In addition, part of the plate body is removed from each side plate in this way to reduce the weight of the entire connecting member 1102. The linear guiding mechanism 1103 includes a guiding block and a guiding rod. Through the cooperation of the guiding block and the guiding rod, the straightness of the linear movement mechanism 11 during movement is ensured.

[0046] Based on the above structure, the present invention proposes a method for detecting the airtightness of a VVT gear, including the following steps:

[0047] S1. First, through the linear movement mechanism 11, the cover body 3 is lifted upward so that the tooling bottom plate 5 is exposed. Then, the VVT gear 4 is placed on the tooling bottom plate 5 so that the first boss 7 forms a fit with the bottom of the VVT gear 4;

[0048] Then, the sealing sleeve 21 is placed on the top of the VVT gear 4, and the second boss 21 of the sealing gland 902 is assembled with the sealing sleeve 21;

[0049] Then, the cover body 3 is moved downward through the linear movement mechanism 11 so that the sealing ring 12 below the cover body 3 is assembled with the groove 13;

[0050] S2. Through the helium leak detector and the air extraction hole 14, the surrounding environment of the area covered by the cover body 3 is evacuated to a vacuum state;

[0051] S3. Helium is filled into the VVT gear 4 through the inflation flange 17;

[0052] S4. The leakage rate of the oil holes of the VVT gear is detected through the helium leak detector;

[0053] S5. After the leakage rate detection is completed, the VVT gear is taken out from the VVT gear helium leak detection fixture;

[0054] S6. After the VVT gear 4 is detected, first, the helium is recovered from the VVT gear helium leak detection fixture, and then the VVT gear 4 is taken out from the VVT gear helium leak detection fixture.

[0055] As described above, in the present invention, since the filling block 19 is installed in the concave portion 18 of the first boss 7, after helium is filled into the VVT gear, it will flow along the gap between the filling block 19 and the VVT gear 4. Through this setting, the usage amount of helium is reduced, and it is convenient to recover helium after the detection is completed, so as to reduce the detection cost.

[0056] Finally, it should be noted that in the present invention, the sealing ring not only has the sealing ring 12 provided at the bottom of the cover body 3, but also other corresponding types of sealing rings need to be provided at other docking positions and positions that need to be sealed to ensure the sealing performance of the entire device.

[0057] The above description is only the preferred embodiment of the present application and the description of the applied technical principle. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solution formed by replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

[0058] Except for the technical features described in the specification, the remaining technical features are known to those skilled in the art. To highlight the innovative features of the present invention, the remaining technical features are not described herein again.

Claims

1. A helium leak detection fixture for a VVT gear, characterized in that, It includes a base and a leak detection tooling. A cover body for accommodating the leak detection tooling is provided on the base. The leak detection tooling is installed inside the cover body, and a vacuum environment is formed through the cover body. The leak detection tooling includes a tooling base plate and a fixture body provided on the tooling base plate and used for carrying the VVT gear. A first boss extending upward is provided in the middle of the fixture body. The bottom end face of the VVT gear is placed on the first boss and sealed with the first boss. A concave portion is further provided on the top surface of the first boss, and a filling block with a convex cross-section is placed in the concave portion. There is a gap between the filling block and the concave portion. A cover is fixed to the top of the cover body. The bottom center of the cover is docked with the top of the VVT gear through a pressing-down assembly. An air hole distributed in the vertical direction is provided in the center of the pressing-down assembly. After the pressing-down assembly is docked with the VVT gear, one end of the air hole is docked with the shaft hole located in the center of the VVT gear, and the other end of the air hole is connected to a helium leak detection inflation assembly. The pressing-down assembly includes a press head fixedly installed at the center of the bottom of the cover. A sealing gland is provided below the press head. The sealing gland overlaps the top end of the VVT gear and is sealed with the top end of the VVT gear. The air hole includes a first air hole and a second air hole. The first air hole is provided in the press head and arranged along the axis of the press head. The second air hole is provided in the sealing gland and arranged along the axis of the sealing gland. The first air hole and the second air hole are coaxially arranged, and the first air hole and the second air hole are sealed and docked. The first air hole in the press head is connected to the helium leak detection inflation assembly through an inflation flange. The press head is fixedly installed on the bottom end face of the inflation flange. The inflation flange is fixedly installed in the middle of the cover. The bottom of the inflation interface of the inflation flange is sealed and docked with the first air hole. The top of the cover drives the cover body to move up and down through a linear movement mechanism. A sealing ring is fixed to the bottom of the cover body. A groove matching the sealing ring is provided on the base. A suction hole is provided on the base, and the suction hole is connected to a helium leak detector.

2. The VVT gear helium leak detection fixture according to claim 1, wherein The tooling base plate is connected to the base through a plurality of guide columns. The tooling base plate moves up and down along the guide columns. The guide columns are fixedly installed on the top surface of the base.

3. The VVT gear helium leak detection fixture according to claim 2, characterized in that, A spring is further provided between the tooling base plate and the base.

4. A method for detecting the airtightness of a VVT gear, characterized in that, It includes the following steps: Install the VVT gear on the VVT gear helium leak detection fixture according to any one of claims 1 to 3. Use a helium leak detector to evacuate the surrounding environment of the VVT gear helium leak detection fixture to a vacuum state. Fill helium into the VVT gear. Use a helium leak detector to detect the leakage rate of the oil hole of the VVT gear. After the leakage rate detection is completed, take out the VVT gear from the VVT gear helium leak detection fixture. Among them, the VVT gear helium leak detection fixture includes a base and a leak detection tooling. A cover body for accommodating the leak detection tooling is provided on the base. The leak detection tooling is installed inside the cover body, and a vacuum environment is formed through the cover body. The leak detection tooling includes a tooling base plate and a fixture body disposed on the tooling base plate and used for carrying the VVT gear. A first boss extending upward is provided in the middle of the fixture body. The bottom end face of the VVT gear is placed on the first boss and sealed with the first boss. A cover is fixed to the top of the cover body. The center bottom of the cover is docked with the top of the VVT gear through a downward pressing component. An air hole distributed in the vertical direction is provided in the center of the downward pressing component. After the downward pressing component is docked with the VVT gear, one end of the air hole is docked with the shaft hole located in the center of the VVT gear, and the other end of the air hole is connected to a helium leak detection inflation component. The top of the cover drives the cover body to move up and down through a linear movement mechanism. A sealing ring is fixed to the bottom of the cover body, and a groove matching the sealing ring is provided on the base. A suction hole is provided on the base, and the suction hole is connected to a helium leak detector.

5. The airtightness detection method of the VVT gear according to claim 4, characterized in that, After the detection of the VVT gear is completed, first recover the helium from the VVT gear helium leak detection fixture, and then take out the VVT gear from the VVT gear helium leak detection fixture.

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