A method and tool for press fitting a negative pressure or slightly positive pressure hydraulic bushing

Abstract

A kind of press mounting method and press mounting tool of negative pressure or micro-positive pressure hydraulic bushing, press mounting tool includes positioning support, upper press head and lower press head, when press mounting, outer tube is placed in positioning support, upper press head and lower press head are inserted into upper chamber and lower chamber of the other side of hydraulic cavity rubber wall respectively, and upper press head and lower press head are in interference contact with upper chamber and lower chamber respectively, make rubber wall deform and protrude towards the inside of hydraulic cavity, extrude rubber main spring and flow channel and stop in combination, when extruding in place, upper press head and lower press head are removed, complete press mounting operation.The present application is by being set with upper press head and lower press head respectively with the rubber of upper chamber and lower chamber of hydraulic bushing interference fit, make rubber deform and protrude towards the inside of hydraulic cavity, to control the amount of damping liquid that can be filled in the inside of hydraulic cavity, also reduce the extrusion force of damping liquid to rubber wall in necking and press mounting process, control the deformation of rubber, improve the durability of product.

Description

Technical Field

[0001] This invention relates to a pressing method and pressing fixture for hydraulic bushings, specifically to a pressing method and pressing fixture for negative pressure or slightly positive pressure hydraulic bushings. Background Technology

[0002] Hydraulic bushings are widely used vibration damping components in automobiles. Compared to traditional rubber bushings, hydraulic bushings can provide greater viscous damping characteristics within a specific frequency range, improving the overall NVH performance of the vehicle. A hydraulic bushing mainly consists of a rubber main spring, a plastic flow channel, a stop, an outer tube, and damping fluid. The rubber main spring comprises an inner sleeve, an inner cage, and rubber, which connects the inner sleeve and inner cage into a single unit. The stop and plastic flow channel are then installed together and pressed into the outer tube. The fluid encapsulation is mainly divided into wet and dry filling. During the necking or pressing process after hydraulic filling, the reduced outer diameter of the product causes the damping fluid within the cavity to be squeezed, resulting in increased deformation of the hydraulic chamber wall and significantly impacting the product's durability. For example, invention applications CN202310251209.4, entitled "A wet filling device and method for hydraulic bushings", and CN202310202714.X, entitled "A dry filling device and method for pre-installed hydraulic bushings", respectively use wet and dry pressing to form hydraulic bushings, but neither of them mentions the problem of rubber deformation in the hydraulic chamber, nor how to avoid it. Therefore, it will affect the performance of the hydraulic bushings. Summary of the Invention

[0003] This invention addresses the problem of excessive rubber deformation in the hydraulic chamber during the necking or pressing process of current hydraulic bushings, which affects performance. It proposes a pressing method and tooling for negative pressure or slightly positive pressure hydraulic bushings, which can effectively reduce the risk of rubber fatigue caused by excessive cavity pressure during product necking and pressing, and can effectively improve product durability.

[0004] The technical means adopted by this invention to solve the above problems is as follows: a press-fitting method for a negative pressure or slightly positive pressure hydraulic bushing, wherein an upper press head and a lower press head are respectively inserted into the upper and lower chambers on the other side of the rubber wall of the hydraulic cavity, and during press-fitting, the upper and lower press heads are in interference contact with the upper and lower chambers respectively, causing the rubber wall to deform and bulge into the hydraulic cavity; after the hydraulic bushing is pressed into place, the upper and lower press heads are removed, completing the press-fitting operation. By pre-deforming the rubber wall into the hydraulic cavity, the size of the hydraulic cavity is reduced, the amount of liquid injected is controlled, and excessive deformation caused by excessive compression of the rubber wall by the damping fluid during press-fitting is avoided, which would affect performance.

[0005] A press-fitting fixture for a negative pressure or slightly positive pressure hydraulic bushing includes a positioning support, an upper press head, and a lower press head. The positioning support has an internally hollow structure. The lower surface of the upper press head is provided with a downwardly protruding upper pressure plate, and the upper surface of the lower press head is provided with an upwardly protruding lower pressure plate. The bottom end of the upper pressure plate is interference-fitted with the side of the upper chamber of the hydraulic bushing facing the hydraulic cavity, and the top end of the lower pressure plate is interference-fitted with the side of the lower chamber of the hydraulic bushing facing the hydraulic cavity.

[0006] Furthermore, the inner wall of the pressing head is provided with an inner step that matches the mandrel. During the pressing process, when the mandrel contacts the inner step, it ensures the accurate relative position of the rubber main spring and the pressing head.

[0007] Furthermore, a retaining ring is provided on the inner wall of the positioning support. During press fitting, the outer tube is placed on the retaining ring inside the positioning support to position the retaining ring.

[0008] Furthermore, the outer wall of the pressure head is provided with an outer step corresponding to the retaining ring.

[0009] Furthermore, the press-fitting fixture also includes a necking mechanism located above the positioning support. The necking mechanism includes a locking flap that can be opened and a locking device for locking and opening the flap.

[0010] Furthermore, the valve mold comprises two valve molds, which are rotatable about a pin at one end, and a locking device is provided at the other end of the two valve molds.

[0011] Furthermore, the pressing fixture also includes a base, a positioning support is set on the base, and a spring is installed inside the base, with the upper surface of the spring pressing against the lower pressing head.

[0012] Furthermore, the base is provided with countersunk holes, and the lower surface of the positioning support corresponding to the countersunk hole is provided with screw holes. Bolts pass through the countersunk holes and screw holes to fix the positioning support on the base.

[0013] Furthermore, the upper surface of the base is provided with an annular hole, and one end of the spring is located inside the annular hole.

[0014] Furthermore, a positioning hole corresponding to the position of the inner hole of the mandrel is provided at the center of the upper pressure head, and a positioning pin is provided in the positioning hole. The positioning pin passes through both the positioning hole of the upper pressure head and the inner hole of the mandrel to ensure the accurate positioning of the upper pressure head and the rubber main spring.

[0015] Furthermore, a guide hole is provided at one end of the base, and one end of the guide post is set in the guide hole; a guide hole matching the guide post is provided at one end of the upper pressure head. The upper pressure head is positioned by matching the guide post with the guide hole.

[0016] Furthermore, the thickness of the upper pressure head at the guide hole end is less than the thickness at the end that contacts the rubber main spring.

[0017] The beneficial effects of this invention are:

[0018] 1. This invention, by setting an upper pressure head and a lower pressure head to interfere with the rubber in the upper and lower chambers of the hydraulic bushing respectively, causes the rubber to deform and protrude into the hydraulic cavity. This controls the amount of damping fluid that can be filled into the hydraulic cavity, thereby reducing the pressure of the damping fluid on the rubber wall during necking and pressing, controlling rubber deformation, and improving product durability. Furthermore, in actual use, the filling volume can be adjusted by adjusting the interference fit between the upper and lower pressure heads and the upper and lower chambers, thus adjusting the pressure of the damping fluid on the rubber chamber wall after actual product assembly.

[0019] 2. By setting an independent necking mechanism above the positioning support, the present invention can realize the necking and guiding functions, and can avoid the outer tube cutting the outer surface of the rubber.

[0020] 3. By installing a spring below the pressing head, the spring can automatically eject the hydraulic bushing after the product is packaged and the pressing equipment is unloaded, making it easy to remove the product. Attached Figure Description

[0021] Figure 1 A schematic diagram showing the deformation and protrusion of rubber caused by the reduction in the outer diameter of the product due to the necking or press fitting of the hydraulic bushing.

[0022] Figure 2 This is a schematic diagram of the necking mechanism used to neck the rubber main spring during the press-fitting process in Example 1.

[0023] Figure 3 for Figure 2 Cross-sectional view;

[0024] Figure 4 This is a schematic diagram of the hydraulic bushing being pressed into place in Example 1;

[0025] Figure 5 for Figure 4 Cross-sectional view;

[0026] Figure 6 This is a schematic diagram of the upper pressure head structure in Example 1;

[0027] Figure 7 for Figure 6 Another structural diagram;

[0028] Figure 8 This is a schematic diagram of the necking mechanism in Example 1;

[0029] Figure 9 for Figure 8 Another structural diagram;

[0030] Figure 10 This is a schematic diagram of the positioning support structure in Example 1;

[0031] Figure 11 for Figure 10 Cross-sectional view;

[0032] Figure 12 Here is a schematic diagram of the pressure head structure in an embodiment;

[0033] Figure 13 This is a schematic diagram of the base structure in Embodiment 1;

[0034] Figure 14 for Figure 13 Another angle diagram;

[0035] In the diagram: 1. Hydraulic bushing, 11. Mandrel, 111. Inner hole, 12. Hydraulic cavity, 13. Upper chamber, 14. Lower chamber, 15. Rubber, 16. Outer tube, 2. Necking mechanism, 21. Flap mold, 22. Pin, 23. Locking device, 231. Connecting shaft, 232. Screw, 233. Washer, 234. Eccentric handle, 3. Upper pressure head, 31. Upper pressure plate, 32. Positioning hole, 33. Positioning pin, 34. Guide hole, 35. Guide tube, 4. Lower pressure head, 41. Lower pressure plate, 42. Outer step, 43. Inner step, 5. Positioning support, 51. Retaining ring, 52. Pin hole, 53. Screw hole, 6. Base, 61. Annular hole, 62. Countersunk hole, 7. Spring, 8. Guide pin, 9. Bolt. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings. The drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0037] During the press-fitting process of hydraulic bushing 1, such as Figure 1 As shown, when compressed, the damping fluid in the hydraulic cavity 12 will squeeze the rubber 15, causing the free rubber 15 to deform and protrude into the upper chamber 13 or the lower chamber 14, which has a very adverse effect on the product's durability. Example 1

[0038] A press-fitting fixture for a negative pressure or slightly positive pressure hydraulic bushing, such as Figures 2-5 As shown, the press-fitting fixture as a whole includes an upper press head 3, a necking mechanism 2, a lower press head 4, a positioning support 5, a spring 7, and a base 6. Figure 2 , Figures 6-7 , Figures 13-14As shown, the upper pressure head 3 and the base 6 are circular at one end for pressing, and the other end extends beyond the axial position of the lower pressure head 4, the positioning support 5, the spring 7 and the base 6. The end of the base 6 away from the pressing part is provided with a guide post 8, and the end of the upper pressure head 3 away from the pressing part is provided with a guide hole 34 that cooperates with the guide post 8. The upper pressure head 3 and the base 6 are positioned by the cooperation of the guide hole 34 and the guide post 8, thereby positioning the entire pressing fixture and avoiding displacement during the pressing process that could damage the hydraulic bushing components.

[0039] This embodiment describes the tooling used in wet pressing, such as... Figure 6 and Figure 13 As shown, guide tubes 35 are provided on the upper surface of the upper pressure head 3 and the lower surface of the base 6, so that the upper pressure head 3 or the base 6 will not adhere to the hydraulic equipment during the pressing process.

[0040] like Figure 6 and Figure 7 As shown, the upper pressure head 3 has a positioning hole 32 at the middle position for pressing. The position of the positioning hole 32 corresponds to the inner hole 111 of the mandrel 11. A positioning pin 33 passes through the positioning hole 32 and the inner hole 111 to position the upper pressure head 3 and the rubber main spring, ensuring the correct position between the upper pressure plate 31 and the upper chamber 13. Moreover, as Figure 1 , Figure 3 , Figures 5-7 As shown, the positioning hole 32, the inner hole 111, and the positioning post 33 are all structures formed by one large and one small hole, which ensures the positioning function.

[0041] like Figure 7 As shown, the lower surface of the upper pressure head 3 is provided with a downward protruding upper pressure plate 31. During pressing, the upper pressure plate 31 extends into the upper chamber 13 of the hydraulic bushing 1, and the bottom of the upper pressure plate 31 is interference-fitted with the upper chamber 13 near the hydraulic cavity 12, squeezing the free rubber 15 between the hydraulic cavity 12 and the upper chamber 13, causing it to deform and protrude toward the hydraulic cavity 12.

[0042] Correspondingly, such as Figure 12 As shown, the upper surface of the lower pressure head 4 is provided with an upwardly protruding lower pressure plate 41. During pressing, the lower pressure plate 41 extends into the lower chamber 14 of the hydraulic bushing 1, and the top of the lower pressure plate 41 is interference-fitted with the lower chamber 14 near the hydraulic cavity 12, squeezing the free rubber 15 between the hydraulic cavity 12 and the lower chamber 14, causing it to deform and protrude towards the hydraulic cavity 12. In this way, through the cooperation between the upper pressure plate 31 and the lower pressure plate 41, the volume of the hydraulic cavity 12 during filling is reduced, that is, the amount of filling fluid into the hydraulic cavity 12 is reduced. After pressing is completed and the upper pressure head 3 and the lower pressure head 4 are removed, the hydraulic cavity 12 can maintain a negative pressure or a slight positive pressure, reducing the risk of rubber fatigue caused by excessive pressure in the hydraulic cavity 12, and effectively improving the product's durability.

[0043] In addition, such as Figure 12 As shown, the lower pressure head 4 has an inner step 43 on the inner side wall of the lower pressure plate 41. During pressing, the inner step 43 abuts against the bottom end of the mandrel 11 to ensure the accurate vertical position between the lower pressure plate 41 and the lower chamber 14. The outer side of the lower pressure head 4 has an outer step 42 that contacts the internal structure of the positioning support 5, so that the lower pressure head 4 can be blocked inside the positioning support 5.

[0044] like Figure 8 and Figure 9 As shown, the necking mechanism 2 includes two rotatable lobes 21 and a locking device 23 for locking or unlocking the two lobes 21. The lobes 21 are mounted on the positioning support 5 via pins 22 at one end, and the lobes 21 can rotate around the pins 22. The locking device 23 includes a connecting shaft 231, a screw 232, a washer 233, and an eccentric handle 234. One end of the screw 232 is located at the end of one lobe 21 away from the pin 22 via the connecting shaft 231, and the other end is connected to the washer 233 and the eccentric handle 234. The washer 233 and the eccentric handle 234 can be mounted to the end of the other lobe 21 away from the pin 22 to lock the two lobes 21. Of course, the locking device 23 can also be implemented using other locking methods, such as the engagement of a screw and a nut. Furthermore, when the necking mechanism 2 is locked, the interior formed by the two lobes 21 has a structure that is larger at the top and smaller at the bottom, providing a certain guiding effect.

[0045] like Figure 6 and Figure 7 As shown, the thickness of the end of the upper pressure head 3 used for pressing is greater than the thickness of the end away from the pressing end. When the pressing reaches a certain extent, the two valves 21 of the necking mechanism 2 open, and the upper pressure head 3 can continue to press down so that the hydraulic bushing 1 is pressed into place, and the necking mechanism 2 will not interfere.

[0046] like Figure 10 and Figure 11 As shown, the positioning support 5 has a hollow internal structure, and a retaining ring 51 is provided on its inner wall. During press fitting, the outer tube 16 of the hydraulic bushing 1 is placed above the retaining ring 51, while the lower pressing head 4 is placed below the retaining ring 51. Figure 10 As shown, the top of the positioning support 5 is provided with a pin hole 52. After the pin 22 is inserted into the pin hole 52, the necking mechanism 2 is assembled onto the positioning support 5. Figure 11 As shown, a screw hole 53 is provided at the bottom of the positioning support 5. Correspondingly, as... Figure 13 and Figure 14 As shown, the base 6 is provided with a countersunk hole 62. After the bolt 9 passes through the countersunk hole 62 and the screw hole 53, the positioning support 5 is fixed on the base 6.

[0047] In addition, such as Figure 14As shown, an annular hole 61 is provided on the upper surface of the base 6, and a spring 7 is placed in the annular hole 61 to push the lower pressure head 4 in the positioning support 5.

[0048] The pressing method of the pressing fixture in the above embodiments is as follows: Figure 3 As shown, first assemble the base 6, spring 7, pressing head 4, positioning support 5, and necking mechanism 2 in order from bottom to top, and then lock the positioning support 5 to the base 6 with bolts 9. Then place the above components into the filling liquid pool, place the outer tube 16 on the retaining ring 51 inside the positioning support 5, and lock the necking mechanism 2.

[0049] After assembling the rubber main spring with the stop and flow channel, place it on the upper end face of the necking mechanism 2. The hydraulic bushing 1 is pre-assembled through the space between the two flap molds 21. At the same time, adjust the relative position between the rubber main spring and the lower pressure head 4 so that the lower pressure plate 41 extends into the lower chamber 14.

[0050] The upper pressure head 8 is placed above the rubber main spring. The upper pressure head 8 is positioned using the guide hole 34 and the guide post 8. Simultaneously, the upper pressure head 3 and the rubber main spring are positioned using the positioning post 33. The hydraulic press punch presses down on the upper pressure head 3, causing the upper pressure head 8 and the rubber main spring to move downwards together until they can no longer move, completing the first stage of assembly. Figure 3 As shown.

[0051] Open the necking mechanism 2, rotate the two valve molds 21 to move the necking mechanism 2 away from the positioning support 5, and the hydraulic press punch continues to move downwards until it can no longer move, completing the second stage of assembly. Figure 5 As shown.

[0052] The hydraulic press punch is unloaded, and the hydraulic bushing 1 automatically pops out under the action of the compressed spring 3, removing the product and completing the pressing operation.

[0053] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions should also fall within the protection scope of the invention, which should be defined by the claims.

Claims

1. A method for press-fitting a negative pressure or slightly positive pressure hydraulic bushing, characterized in that: The upper pressure head (3) and the lower pressure head (4) are respectively inserted into the upper chamber (13) and the lower chamber (14) on the other side of the rubber (15) wall of the hydraulic cavity (12). During the pressing process, the upper pressure head (3) and the lower pressure head (4) are in interference contact with the upper chamber (13) and the lower chamber (14) respectively, so that the rubber (15) wall deforms and protrudes into the hydraulic cavity (12). After the hydraulic bushing (1) is pressed into place, the upper pressure head (3) and the lower pressure head (4) are removed to complete the pressing operation. By pre-deforming the rubber wall into the hydraulic cavity, the size of the hydraulic cavity is reduced, the amount of liquid injected is controlled, and the necking and excessive compression of the rubber wall by the damping liquid during the pressing process are avoided, which would lead to excessive deformation.

2. A press-fitting fixture for a negative pressure or slightly positive pressure hydraulic bushing, characterized in that: It includes a positioning support (5), an upper pressure head (3) and a lower pressure head (4). The positioning support (5) is a hollow structure. The lower surface of the upper pressure head (3) is provided with an upper pressure plate (31) protruding downwards. The upper surface of the lower pressure head (4) is provided with a lower pressure plate (41) protruding upwards. The bottom end of the upper pressure plate (31) is in interference fit with the side of the upper chamber (13) of the hydraulic bushing (1) facing the hydraulic cavity (12). The top end of the lower pressure plate (41) is in interference fit with the side of the lower chamber (14) of the hydraulic bushing (1) facing the hydraulic cavity (12). By pre-deforming the rubber wall into the hydraulic cavity, the size of the hydraulic cavity is reduced, the amount of liquid injected is controlled, and excessive deformation caused by excessive compression of the rubber wall by the damping liquid during the necking and pressing process is avoided.

3. The press-fitting fixture for negative pressure or slightly positive pressure hydraulic bushings as described in claim 2, characterized in that: The inner wall of the pressure head (4) is provided with an inner step (43) that matches the mandrel (11).

4. The press-fitting fixture for negative pressure or slightly positive pressure hydraulic bushings as described in claim 2, characterized in that: The inner wall of the positioning support (5) is provided with a retaining ring (51).

5. The press-fitting fixture for negative pressure or slightly positive pressure hydraulic bushings as described in claim 2, characterized in that: The press fitting also includes a necking mechanism (2) located above the positioning support (5). The necking mechanism (2) includes a locking valve (21) that can be opened and locked, and a locking device (23) for locking and opening the valve (21).

6. The press-fitting fixture for negative pressure or slightly positive pressure hydraulic bushings as described in claim 5, characterized in that: The valve mold (21) includes two valve molds, which are assembled on the positioning support (5) by means of pins (22). The two valve molds (21) can rotate around the pin at one end, and the locking device (23) is set at the other end of the two valve molds (21).

7. The press-fitting fixture for negative pressure or slightly positive pressure hydraulic bushings as described in claim 2, characterized in that: The press fitting also includes a base (6), a positioning support (5) is set on the base (6), and a spring (7) is provided inside the base (6), with the upper surface of the spring (7) pressing against the lower press head (4).

8. The press-fitting fixture for negative pressure or slightly positive pressure hydraulic bushings as described in claim 2, characterized in that: The base (6) is provided with countersunk hole (62), and the lower surface of the positioning support (5) corresponding to the countersunk hole (62) is provided with screw hole (53). The bolt (9) passes through the countersunk hole (62) and screw hole (53) to fix the positioning support (5) on the base (6).

9. The press-fitting fixture for negative pressure or slightly positive pressure hydraulic bushings as described in claim 2, characterized in that: The upper pressure head (3) has a positioning hole (32) at its center that corresponds to the position of the inner hole (111) of the mandrel (11), and a positioning post (33) is provided in the positioning hole (32).

10. The press-fitting fixture for negative pressure or slightly positive pressure hydraulic bushings as described in claim 2, characterized in that: A guide hole is provided at one end of the base (6), and one end of the guide post (8) is set in the guide hole; a guide hole (34) matching the guide post (8) is provided at one end of the upper pressure head (3); and the thickness of the upper pressure head (3) at the end of the guide hole (34) is less than the thickness at the end in contact with the rubber main spring.

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