A piston arm retaining ring mounting fixture and assembly process for an automotive air supply unit.

Abstract

This invention discloses a piston arm retaining ring installation fixture and assembly process for an automotive air supply unit. It includes a pre-installed positioning plate, one end of which has a retaining ring positioning platform for maintaining the retaining ring in an expanded state. The fixture further includes: a variable-diameter positioning pin for center-aligning with the retaining ring positioning platform; a push rod that can move axially along the variable-diameter positioning pin to push the retaining ring on the pin into a sleeve on the outside of the retaining ring positioning platform; and a pressure plate with a groove into which at least the portion of the pre-installed positioning plate containing the retaining ring positioning platform can be embedded. The width of the groove is smaller than the diameter of the retaining ring, and the retaining ring disengages from the retaining ring positioning platform when the retaining ring positioning platform moves relative to the groove. This invention solves the problem of accurate installation when using snap-fit ​​devices to connect the tail ends of two piston arms within an existing air supply unit.

Description

Technical Field

[0001] This invention relates to the field of automotive air supply unit technology, specifically to a piston arm retaining ring mounting fixture and assembly process for an automotive air supply unit. Background Technology

[0002] As automotive comfort requirements increase, air suspension systems have rapidly developed, and electronic product designs are trending towards modularity and miniaturization. Closed-loop air supply units (ASUs) have gained widespread customer acceptance due to their high inflation efficiency and minimal external gas exchange. ASUs often feature two reciprocating piston arms driven by a motor. Bearings are installed between the ends of these piston arms, requiring snap-fit ​​fittings to clamp them. Since the connection point between the piston arms is located in the middle of the valve body, the valve body often needs to be a split structure, or an opening at the bottom of the valve body is required to install the snap-fit ​​fittings. Otherwise, it's difficult to install the snap-fit ​​fittings from the outside. However, the bottom of the valve body needs to house the ECU (Electronic Control Unit). If an opening is used for installation at the bottom of the valve body, the ECU would need to be frequently disassembled, affecting the accuracy of the internal electrical components and potentially damaging them. Therefore, a suitable installation tooling and assembly process are needed to address these issues. Summary of the Invention

[0003] This invention provides a piston arm retaining ring mounting fixture and assembly process for an automotive air supply unit, which can solve the problem of difficulty in accurate installation when using retaining clips to snap the tails of the two piston arms inside the existing air supply unit.

[0004] To achieve the above objectives, in a first aspect, the present invention provides the following technical solution: a piston arm retaining ring mounting fixture for an automotive air supply unit, comprising a pre-installed positioning plate, one end of which is provided with a retaining ring positioning platform for keeping the retaining ring in an expanded state; further comprising: a variable diameter positioning pin for center-connecting with the retaining ring positioning platform; a push rod that can move axially along the variable diameter positioning pin to push the retaining ring on the variable diameter positioning pin into a sleeve on the outside of the retaining ring positioning platform; and a pressure plate having a groove, wherein the pre-installed positioning plate is at least provided with a portion containing the retaining ring positioning platform. It can be embedded in the groove, the width of which is smaller than the diameter of the retaining ring. When the retaining ring positioning table moves relative to the groove, the retaining ring disengages from the retaining ring positioning table. The variable diameter positioning pin and push rod expand the retaining ring and quickly position it on the retaining ring positioning table. The pressure plate sends the pre-installed positioning plate and retaining ring from the side of the valve body of the automotive air supply unit to the installation position. At the same time, the relative movement between the groove and the retaining ring positioning table enables the retaining ring to disengage and be installed in the designated position. The retaining ring is accurately installed from the side wall of the valve body using a simple and ingenious tooling.

[0005] Preferably, both the pre-installed positioning plate and the pressure plate are elongated structures, and the groove is located near the end of the pressure plate. This facilitates the relative movement of the pre-installed positioning plate and the pressure plate, and also helps to use the limited space of the assembly channel to send the snap ring into the narrow piston arm mounting cavity.

[0006] Preferably, the pre-installed positioning plate includes an upper base plate and a lower base plate that extends horizontally below the upper base plate. The snap ring positioning platform is located at the end of the lower base plate. When the pre-installed positioning plate is matched with the pressure plate, the lower base plate is embedded in the groove and the upper base plate is located on the upper side of the pressure plate. The upper base plate can limit the position of the lower base plate embedded in the groove so that the pre-installed positioning plate will not fall off the pressure plate. At the same time, the upper base plate is closer to the other end of the pressure plate, which makes it easier to operate when the pre-installed positioning plate and the pressure plate move relative to each other.

[0007] Preferably, when the upper substrate and the pressure plate are attached, the snap ring positioning stage is fully embedded in the groove and the snap ring is disengaged from the snap ring positioning stage. During operation, it is very simple to disengage the snap ring by simply attaching the upper substrate and the pressure plate together.

[0008] Preferably, the snap ring positioning platform has a positioning hole in the middle, and the lower end of the variable diameter positioning pin can be inserted into the positioning hole for positioning, which facilitates quick installation and use of the variable diameter positioning pin and improves efficiency.

[0009] Preferably, the side wall of the snap ring positioning platform is provided with a limiting groove for engaging with the bent limiting part at the opening of the snap ring, which can quickly limit the position of the snap ring.

[0010] Preferably, the variable diameter positioning pin includes a variable diameter column that gradually increases in size from top to bottom and a guide groove disposed on one side of the variable diameter column. The guide groove is engaged with the bent limiting part at the opening of the retaining spring. The outer surface of the variable diameter column is smooth. As the retaining spring moves axially, it can open the retaining spring. At the same time, the guide groove can prevent the retaining spring from rotating when it moves, so that the retaining spring can be sleeved on the retaining spring positioning table at a fixed angle.

[0011] Preferably, the push rod is a sleeve structure with an internal hole that matches the retaining spring, making it easy to operate and preventing misalignment.

[0012] Secondly, the present invention also provides an assembly process for a piston arm retaining ring of an automotive air supply unit, using the mounting fixture described in the first aspect, specifically including the following steps:

[0013] S1. Align the variable diameter positioning pin with the snap ring positioning table on the pre-installed positioning plate, and put the snap ring on the variable diameter positioning pin.

[0014] S2. Use the push rod to put it on the outside of the variable diameter positioning pin and move it axially to push the snap ring to move towards the snap ring positioning table. The snap ring gradually expands and is put on the snap ring positioning table.

[0015] S3. The pre-installed positioning plate and the pressure plate are fitted together and extended from the assembly channel on the side of the valve body of the automotive air supply unit into the piston arm mounting cavity inside the valve body, so that the snap ring positioning table is aligned with the position between the first piston arm and the second piston arm.

[0016] S4. The pre-installed positioning plate moves relative to the pressure plate, and the edge of the snap ring and the groove on the snap ring positioning table interacts, causing the snap ring to disengage from the snap ring positioning table and smoothly engage with the corresponding snap-fit ​​protrusions on the first piston arm and the second piston arm, so that the snap ring connects the first piston arm and the second piston arm.

[0017] Furthermore, in step S4, the relative movement between the pre-installed positioning plate and the pressure plate is specifically achieved by pressing the upper base plate of the pre-installed positioning plate with a thumb from the outer end of the assembly channel, causing the lower base plate to slide downward in the groove. At this time, the snap ring positioning table is fully inserted into the groove, and the edge of the groove squeezes the snap ring until the snap ring disengages from the snap ring positioning table.

[0018] The entire assembly process is simple to operate. It does not require the valve body to be made into a split structure or to use the bottom opening of the valve body to install the snap ring in the middle of the piston arm mounting cavity. Compared with conventional tools, its installation efficiency is greatly improved.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] The installation fixture consists of a variable-diameter locating pin, a push rod, a pre-installed locating plate, and a pressure plate. The variable-diameter locating pin and push rod expand and quickly position the snap ring on the snap ring locating platform. The pressure plate moves the pre-installed locating plate and snap ring from the side of the valve body of the automotive air supply unit to the installation position. Simultaneously, the relative movement between the groove and the snap ring locating platform disengages the snap ring and installs it in the designated position. This simple and ingenious fixture allows for accurate installation of the snap ring from the side wall of the valve body. The entire assembly process is simple to operate and does not require the valve body to be made into a split structure or to use an opening at the bottom of the valve body to install the snap ring in the middle of the piston arm mounting cavity. Compared with conventional tools, its installation efficiency is greatly improved. Attached Figure Description

[0021] Figure 1 This is a partial three-dimensional structural diagram of the installation tooling of the present invention;

[0022] Figure 2 This is a partial cross-sectional view of the installation fixture of the present invention;

[0023] Figure 3This is a three-dimensional structural diagram of the variable diameter locating pin and the pre-installed locating plate of the present invention.

[0024] Figure 4 This is a first perspective view of the pre-installed positioning plate and pressure plate of the present invention.

[0025] Figure 5 This is a second perspective view of the pre-installed positioning plate and pressure plate of the present invention.

[0026] Figure 6 This is an overall perspective view of the air supply unit of the present invention;

[0027] Figure 7 This is a schematic diagram showing the completed assembly of the snap ring of the present invention;

[0028] Figure 8 This is a first schematic diagram of the snap ring assembly process of the present invention;

[0029] Figure 9 This is a second schematic diagram of the snap ring assembly process of the present invention;

[0030] Figure 10 This is a schematic diagram illustrating the assembly process of the pre-installed positioning plate and the pressure plate of the present invention.

[0031] Figure label:

[0032] 1. Push rod; 11. Inner hole; 2. Pre-installed positioning plate; 20. Valve body; 21. Lower base plate; 22. Upper base plate; 23. Positioning hole; 24. Snap ring positioning platform; 3. Variable diameter positioning pin; 30. Piston arm mounting cavity; 31. Variable diameter column; 32. Guide groove; 4. Pressure plate; 40. Assembly channel; 41. Groove; 50. Motor; 60. First piston arm; 70. Second piston arm; 80. Bearing; 90. Snap-fit ​​boss; 100. Snap ring; 101. Bending limit part. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0034] In existing technologies, the air supply unit is an important power source for components such as automotive air springs, such as... Figure 6-7As shown, the air supply unit includes a valve body 20 and a motor 50 mounted on the valve body 20. The valve body 20 is an integral structure with a piston arm mounting cavity 30 inside. A first piston arm 60 and a second piston arm 70 are arranged opposite each other inside the piston arm mounting cavity 30. A bearing 80 is installed between the first piston arm 60 and the second piston arm 70. The bearing 80 is connected to the main shaft of the motor 50 through a crankshaft. The rotation of the main shaft of the motor 50 can drive the first piston arm 60 and the second piston arm 70 to reciprocate synchronously and output high-pressure gas. The retaining ring 100 is a component installed between the first piston arm 60 and the second piston arm 70. It needs to ensure that the first piston arm 60 and the second piston arm 70 move synchronously. The retaining ring 100 is annular with an opening on one side. In order to prevent the retaining ring 100 from falling off during installation, a bending limiting part 101 is provided at one end of the opening of the retaining ring 100. Both the first piston arm 60 and the second piston arm 70 are provided with snap-fit ​​bosses 90. The two sides of the retaining ring 100 are connected by the two snap-fit ​​bosses 90 surrounding and snapping them together. Therefore, when installing the retaining ring 100, the retaining ring 100 needs to be first spread open and moved to one side of the axial direction of the two snap-fit ​​bosses 90, and then the retaining ring 100 is moved axially to snap. However, the internal space of the existing piston arm mounting cavity 30 is very small, and the distance between the middle of the piston arm mounting cavity 30 and the side wall of the valve body 20 is relatively long. Therefore, even if an assembly channel 40 is provided on the side wall of the valve body 20, it is difficult to complete the accurate installation of the retaining ring 100.

[0035] Therefore, the embodiments of the present invention are designed to solve the above problems, such as... Figure 1-10 As shown, the following technical solution is provided: a piston arm retaining ring mounting fixture for an automotive air supply unit, including a pre-installed positioning plate 2, one end of which is provided with a retaining ring positioning platform 24 for keeping the retaining ring 100 in an expanded state; further including: a variable diameter positioning pin 3 for center-connecting with the retaining ring positioning platform 24; a push rod 1, which can move axially along the variable diameter positioning pin 3 to push the retaining ring 100 on the variable diameter positioning pin 3 into the outer side of the retaining ring positioning platform 24; and a pressure plate 4, which is provided with a groove 41, and at least the portion of the pre-installed positioning plate 2 with the retaining ring positioning platform 24 can be embedded in the groove 41. The width of the groove 41 is smaller than the diameter of the snap ring 100. When the snap ring positioning table 24 moves relative to the groove 41, the snap ring 100 is disengaged from the snap ring positioning table 24. The variable diameter positioning pin 3 and the push rod 1 expand the snap ring 100 and quickly position it on the snap ring positioning table 24. The pressure plate 4 sends the pre-installed positioning plate 2 and the snap ring 100 from the side of the valve body 20 of the automotive air supply unit to the installation position. At the same time, the snap ring 100 is disengaged and installed in the designated position by the relative movement of the groove 41 and the snap ring positioning table 24. The snap ring 100 is accurately installed from the side wall of the valve body 20 by using a simple and ingenious tooling.

[0036] Specifically, the groove 41 of the pressure plate 4 is 1-2mm narrower than the diameter of the retaining spring 100. When the pre-installed positioning plate 2 moves relative to the pressure plate 4 (e.g., a sliding distance of 5-8mm), the edge of the groove can precisely peel the retaining spring off the positioning table without the need for manual secondary adjustment. Actual measurements show that the installation time for a single part is reduced to 1-1.5 minutes, the rework rate is reduced to below 0.5%, and labor costs are significantly reduced.

[0037] The diameter range of the variable diameter positioning pin 3 can be adjusted according to the specifications of the snap ring, such as to adapt to snap rings of φ10-φ20mm; the diameter of the snap ring positioning table 24 can be adjusted by replacing the pre-installed positioning plate 2 of different specifications, without the need to replace the tooling as a whole, and its application range covers more than 80% of the piston arm snapping scenarios of automotive air supply units.

[0038] In this embodiment, both the pre-installed positioning plate 2 and the pressure plate 4 are elongated structures. The groove 41 is located near the end of the pressure plate 4, which facilitates the relative movement of the pre-installed positioning plate 2 and the pressure plate 4, and also facilitates the use of the limited space of the assembly channel 40 to send the snap ring 100 into the narrow piston arm mounting cavity 30. Specifically, the pre-installed positioning plate 2 includes an upper base plate 22 and a lower base plate 21 that extends horizontally below the upper base plate 22. The snap ring positioning platform 24 is located at the end of the lower base plate 21. When the pre-installed positioning plate 2 is matched with the pressure plate 4, the lower base plate 21 is embedded in the groove 41, and the upper base plate 22 is located on the upper side of the pressure plate 4. The upper base plate 22 can limit the position of the lower base plate 21 embedded in the groove 41, so that the pre-installed positioning plate 2 will not fall off the pressure plate 4. At the same time, the upper base plate 22 is closer to the other end of the pressure plate 4, which makes it easier to operate when the pre-installed positioning plate 2 and the pressure plate 4 move relative to each other.

[0039] In this embodiment, when the upper substrate 22 is attached to the pressure plate 4, the snap ring positioning stage 24 is fully embedded in the groove 41 and the snap ring 100 is disengaged from the snap ring positioning stage 24. During operation, it is only necessary to attach the upper substrate 22 and the pressure plate 4 to each other to disengage the snap ring 100, which is very simple.

[0040] At the same time, for easy positioning, such as Figure 2 As shown, the snap ring positioning table 24 has a positioning hole 23 in the middle. The lower end of the variable diameter positioning pin 3 can be inserted into the positioning hole 23 for positioning, which facilitates the quick installation and use of the variable diameter positioning pin 3 and improves efficiency.

[0041] To achieve accurate positioning of the snap ring 100, such as Figure 3-5 As shown, the side wall of the snap ring positioning platform 24 is provided with a limiting groove for engaging with the bent limiting part 101 at the opening of the snap ring 100, which can quickly limit the position of the snap ring 100.

[0042] In this embodiment, as Figure 3 As shown, the variable diameter positioning pin 3 includes a variable diameter column 31 that gradually increases in size from top to bottom and a guide groove 32 disposed on one side of the variable diameter column 31. The guide groove 32 is engaged with the bent limiting part 101 at the opening of the retaining spring 100. The outer surface of the variable diameter column 31 is smooth. As the retaining spring 100 moves axially, it can open the retaining spring 100. At the same time, the guide groove 32 can prevent the retaining spring 100 from rotating when it moves, so that the retaining spring 100 can be sleeved on the retaining spring positioning table 24 at a fixed angle.

[0043] In this embodiment, as Figure 1-2 As shown, the push rod 1 is a sleeve structure with an inner hole 11 that matches the snap ring 100, making it easy to operate and preventing any deviation.

[0044] As a specific implementation scheme in this embodiment: Specifically, the pre-installed positioning plate 2 can be made of high-strength aluminum alloy (6061-T6), with a total length of 250mm. The snap ring positioning platform 24 is cylindrical with a diameter of φ16mm, which is 4mm larger than the free diameter of the snap ring, and a height of 8mm. The central positioning hole 23 has a diameter of φ5mm and cooperates with the pin at the lower end of the variable diameter positioning pin 3. The side wall of the snap ring positioning platform 24 is provided with a limiting groove with a depth of 1.5mm and a width consistent with the thickness of the snap ring bending limiting part 101.

[0045] The variable diameter locating pin 3 is made of 45# steel with heat treatment (hardness HRC35-40), and has a total height of 50mm. The variable diameter column 31 has an upper diameter of φ10mm and a lower diameter of φ16mm, which matches the diameter of the snap ring locating table 24, with a taper of 1:6. The guide groove 32 has a depth of 2mm and a width of 3mm, which is compatible with the snap ring bending limiting part 101. The push rod 1 is made of polyoxymethylene (POM), which is more wear-resistant and avoids scratching the snap ring 100, making it easier to operate. The inner hole 11 of the sleeve structure has a diameter of φ16.5mm, which is 0.5mm larger than the inner diameter of the snap ring after expansion. It has a length of 100mm and a wall thickness of 3mm.

[0046] The pressure plate 4 is made of aluminum alloy (6061-T6), with a length of 250mm, a width of 20mm, and a thickness of 5mm; the groove 41 is located 50mm from the end, with a width of 14mm, and the edge of the groove is rounded with a radius of R0.5mm to avoid scratching the valve body.

[0047] In this embodiment, a specific assembly process includes the following steps:

[0048] S1. Positioning and Pre-installation:

[0049] Insert the lower end of the variable diameter positioning pin 3 into the positioning hole 23 of the snap ring positioning table 24 with a fit clearance of 0.03mm to ensure vertical alignment. Place the snap ring 100 on the variable diameter column 31 of the variable diameter positioning pin 3 so that the bending limiting part 101 is embedded in the guide groove 32 to prevent rotation.

[0050] S2. Snap ring expansion and positioning:

[0051] Push rod 1 is sleeved on the outside of the variable diameter positioning pin 3 and pushes the retaining ring 100 axially downward at a speed of 5 mm / s. As the retaining ring 100 slides along the variable diameter column 31, it gradually expands and reaches a diameter of φ16 mm at the lower end, which is just sleeved on the retaining ring positioning table 24. At this time, the bent limiting part 101 is embedded into the limiting groove of the retaining ring positioning table to complete the positioning. At this time, the variable diameter positioning pin 3 and push rod 1 are removed.

[0052] S3. Insert into the installation position:

[0053] The lower base plate 21 of the pre-installed positioning plate 2 is embedded in the groove 41 of the pressure plate 4, and the upper base plate 22 is placed on the upper surface of the pressure plate. Holding the tail of the pressure plate 4, the assembly of the two is inserted into the piston arm mounting cavity 30 from the side assembly channel 40 of the valve body 20. By visual inspection or endoscopy, the snap ring positioning table 24 is aligned between the snap-fit ​​protrusions 90 of the first piston arm 60 and the second piston arm 70.

[0054] S4. Snap ring disengagement and installation

[0055] Press the upper base plate 22 of the pre-installed positioning plate 2 with your thumb, causing the lower base plate 21 to slide down 6mm in the groove 41. At this time, the snap ring positioning platform 24 is fully inserted into the groove 41. The edge of the groove squeezes the snap ring 100, causing it to disengage from the positioning platform. The snap ring 100 contracts under its own elasticity and fits onto the two snap-fit ​​protrusions 90, completing the connection. Pull out the pre-installed positioning plate 2 and the pressure plate 4 in the opposite direction, and the assembly is complete.

[0056] After testing 100 identical automotive air supply units, the installation success rate was 100%; the average installation time was 1.2 minutes per unit.

[0057] Therefore, in this embodiment, the long strip-shaped pre-installed positioning plate 2 and the pressure plate 4 are used together. The length of the plate can be set to 200-300mm to match the depth of the assembly channel. The snap ring 100 is pre-positioned on the snap ring positioning table 24 and then sent into the installation position through the side channel. This solves the core pain point that the tool cannot penetrate into the narrow space and achieves precise installation without changing the valve body structure.

[0058] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0059] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly and specifically defined.

[0060] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

Claims

1. A piston arm retaining ring mounting fixture for an automotive air supply unit, comprising a pre-installed positioning plate (2), wherein one end of the pre-installed positioning plate (2) is provided with a retaining ring positioning platform (24) for keeping the retaining ring (100) in an expanded state, characterized in that, Also includes: A variable diameter locating pin (3) is used to align with the center of the snap ring locating table (24); The push rod (1) can move axially along the variable diameter positioning pin (3) to push the snap ring (100) on the variable diameter positioning pin (3) into the outer side of the snap ring positioning table (24); The pressure plate (4) has a groove (41) provided on it. At least one part of the pre-installed positioning plate (2) with a snap ring positioning platform (24) can be embedded in the groove (41). The width of the groove (41) is smaller than the diameter of the snap ring (100). When the snap ring positioning platform (24) moves relative to the groove (41), the snap ring (100) is disengaged from the snap ring positioning platform (24).

2. The piston arm retaining ring mounting fixture for an automotive air supply unit according to claim 1, characterized in that: The pre-installed positioning plate (2) and the pressure plate (4) are both elongated structures, and the groove (41) is located near the end of the pressure plate (4).

3. The piston arm retaining ring mounting fixture for an automotive air supply unit according to claim 2, characterized in that: The pre-installed positioning plate (2) includes an upper base plate (22) and a lower base plate (21) that extends horizontally below the upper base plate (22). The snap ring positioning stage (24) is located at the end of the lower base plate (21). When the pre-installed positioning plate (2) matches the pressure plate (4), the lower base plate (21) is embedded in the groove (41) and the upper base plate (22) is located on the upper side of the pressure plate (4).

4. The piston arm retaining ring mounting fixture for an automotive air supply unit according to claim 3, characterized in that: When the upper substrate (22) is attached to the pressure plate (4), the snap ring positioning stage (24) is fully embedded in the groove (41) and the snap ring (100) is disengaged from the snap ring positioning stage (24).

5. The piston arm retaining ring mounting fixture for an automotive air supply unit according to claim 3, characterized in that: The circlip positioning platform (24) is provided with a positioning hole (23) in the middle, and the lower end of the variable diameter positioning pin (3) can be inserted into the positioning hole (23) for positioning.

6. The piston arm retaining ring mounting fixture for an automotive air supply unit according to claim 5, characterized in that: The side wall of the snap ring positioning platform (24) is provided with a limiting groove for engaging with the bent limiting part (101) at the opening of the snap ring (100).

7. The piston arm retaining ring mounting fixture for an automotive air supply unit according to claim 6, characterized in that: The variable diameter positioning pin (3) includes a variable diameter column (31) that gradually increases in size from top to bottom and a guide groove (32) provided on one side of the variable diameter column (31). The guide groove (32) is engaged with the bent limiting part (101) at the opening of the snap ring (100).

8. The piston arm retaining ring mounting fixture for an automotive air supply unit according to claim 3, characterized in that: The push rod (1) is a sleeve structure, and its interior is provided with an inner hole (11) that matches the snap ring (100).

9. An assembly process for a piston arm retaining spring in an automotive air supply unit, characterized in that, The installation fixture described in any one of claims 3-8 specifically includes the following steps: S1. Position the variable diameter positioning pin (3) with the snap ring positioning table (24) on the pre-installed positioning plate (2), and put the snap ring (100) on the variable diameter positioning pin (3); S2. Use push rod (1) to fit on the outside of the variable diameter positioning pin (3) and move axially to push the snap ring (100) to move towards the snap ring positioning table (24). The snap ring (100) gradually expands and fits on the snap ring positioning table (24). S3. The pre-installed positioning plate (2) and the pressure plate (4) are put together and extended from the assembly channel (40) on the side of the valve body (20) of the car air supply unit into the piston arm mounting cavity (30) inside the valve body (20), so that the snap ring positioning table (24) is aligned with the position between the first piston arm (60) and the second piston arm (70). S4. The pre-installed positioning plate (2) moves relative to the pressure plate (4). The edges of the snap ring positioning table (24) interact with the snap ring (100) and the groove (41), causing the snap ring (100) to disengage from the snap ring positioning table (24) and smoothly engage with the corresponding snap-fit ​​bosses (90) on the first piston arm (60) and the second piston arm (70), so that the snap ring (100) connects the first piston arm (60) and the second piston arm (70).

10. The assembly process of the piston arm retaining ring of the automotive air supply unit according to claim 9, characterized in that: In step S4, the relative movement between the pre-installed positioning plate (2) and the pressure plate (4) is specifically achieved by pressing the upper substrate (22) of the pre-installed positioning plate (2) with a thumb from the outer end of the assembly channel (40), causing the lower substrate (21) to slide downward in the groove (41). At this time, the snap ring positioning table (24) completely enters the groove (41), and the edge of the groove (41) squeezes the snap ring (100) until the snap ring (100) disengages from the snap ring positioning table (24).

Images