Double-plunger tensioner with sealing ring

Abstract

The utility model provides a double plunger tensioner with a sealing ring, which relates to the field of tensioners and comprises a shell, a mounting cavity with an opening at one end is arranged on the shell, a plunger is assembled in the mounting cavity in a sliding manner, an annular assembling groove is concavely arranged on the outer wall of a skirt sealing section of the plunger and / or the inner wall of the mounting cavity, the sealing ring is arranged in the assembling groove, and the sealing ring is arranged in the assembling groove. The width of the assembling groove is greater than that of the sealing ring; the side wall of the sealing ring is provided with an opening which is axially communicated to form an oil drainage channel, and the radial size of the sealing ring can be self-adjusted under the action of oil pressure; the diameter of the sealing ring ranges from 8 mm to 20 mm, the width of the sealing ring ranges from 0.1 mm to 10 mm, the thickness of the sealing ring ranges from 0.1 mm to 3 mm, and the distance between openings ranges from 0 mm According to the double-plunger tensioner with the sealing ring, clearance leakage of an original tensioner is optimized, the length of the sealing section of the skirt portion of the plunger is shortened, and the space of the tensioner is more compact.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile powertrain chain systems, in particular to a double-plunger tensioner with a sealing ring. Background Art

[0002] The hydraulic tensioner is a core component in the timing chain system of a powertrain. Its dynamic characteristics are an important part of ensuring that the timing chain drive and valve timing phase remain in the best working state, and have an important impact on whether the engine can work normally. The double-plunger tensioner with a sealing ring mainly changes the hydraulic stiffness and viscous damping through components such as hydraulic valves to achieve dynamic response to the chain system. In addition to hydraulic components, the gap leakage between the plunger and the housing hole is also an important factor affecting the damping and stiffness of the tensioner.

[0003] The double plunger hydraulic tensioner can adjust the chain to the required minimum tension under low load excitation, and is a new type of tensioner that can reduce friction loss. However, under high load excitation, the leakage of the gap between the primary steel plunger and the inner hole of the aluminum shell will increase dramatically due to the increase in temperature, which will lead to large fluctuations in the system dynamic amplitude, poor system control, and other problems, and is often accompanied by noise and severe wear of moving parts.

[0004] As for the gap leakage between the plunger and the housing, the leakage is currently reduced mainly by controlling the manufacturing tolerance of parts or increasing the length of the sealing section. However, due to the limitations of manufacturing precision and spatial layout, these methods cannot effectively control the flow rate within a reasonable range and cannot solve the problem of temperature fluctuations. Utility Model Content

[0005] In order to overcome at least one defect in the above prior art, the utility model provides a double-plunger tensioner with a sealing ring, which optimizes the gap leakage of the original tensioner, shortens the length of the plunger skirt sealing section, and makes the tensioner space more compact.

[0006] The utility model provides a double-plunger tensioner with a sealing ring: comprising a shell, a mounting cavity with an opening at one end is provided on the shell, a plunger is slidably mounted in the mounting cavity, an oil inlet connected with the closed end of the mounting cavity is provided on the shell, an annular mounting groove is concavely provided on the outer wall of the skirt sealing section of the plunger and / or the inner wall of the mounting cavity, a sealing ring is mounted in the mounting groove, and the width of the mounting groove is greater than the width of the sealing ring; an axially connected opening is provided on the side wall of the sealing ring to form an oil leakage channel, and the radial size of the sealing ring can be self-adjusted under the action of oil pressure; the diameter of the sealing ring is 8-20 mm, the width is 0.1-10 mm, the thickness is 0.1-3 mm, and the spacing at the opening is 0-5 mm.

[0007] Compared with the prior art, the double plunger tensioner with a sealing ring of the utility model has the following advantages:

[0008] In the double plunger tensioner with sealing ring of the utility model, a sealing ring is arranged between the outer wall of the skirt sealing section of the plunger and the inner wall of the installation cavity, and the leakage of the gap between the tensioner housing and the plunger is controlled by the sealing ring; when working, the sealing ring expands radially under the action of the oil pressure in the tensioner cavity and closes to the hole wall to limit the leakage of the gap, thereby improving the hydraulic stiffness of the tensioner and achieving better control of the system; due to the sealing function of the sealing ring, temperature and oil pressure fluctuations are no longer the main factors affecting the flow change, and the system performance is more stable under various conditions, so the application occasions are wider; based on the sealing effect of the sealing ring, the length of the plunger skirt sealing section can be shortened in this structure compared with the conventional tensioner, making the tensioner space more compact; in addition, the sealing rings of different size series provide more options for the performance adjustment of the tensioner. It can even reduce the use of guide rail parts between cam wheels in the chain system, thereby reducing the system cost.

[0009] As an improvement, the height difference between the sealing ring and the fitting groove is 0.5-1 mm; and the radial clearance between the sealing ring and the fitting groove is 0.1-1 mm. In this structure, the height difference and radial clearance between the sealing ring and the fitting groove are respectively set within a reasonable size range, so that the sealing ring has a relatively precise movable clearance, so that it can better adapt to changes in temperature and oil pressure, thereby better ensuring sealing performance.

[0010] Preferably, the opening is a vertical opening that vertically penetrates the sealing ring axially, or an inclined opening that obliquely penetrates the sealing ring axially, or a right-angle S-shaped opening that penetrates the sealing ring axially.

[0011] Further improved, the installation chamber includes a primary piston chamber and a secondary piston chamber, the primary piston chamber is equipped with a primary plunger, the secondary piston chamber is equipped with a secondary plunger, and the sealing ring is arranged between the outer wall of the primary plunger and the inner wall of the piston chamber; a low-pressure chamber is arranged on the shell, the primary piston chamber and the secondary piston chamber are both connected to the low-pressure chamber, a primary one-way valve is installed between the primary piston chamber and the low-pressure chamber, and a secondary one-way valve is installed between the secondary piston chamber and the low-pressure chamber.

[0012] Further improved, the first-level one-way valve is located at the bottom of the first-level piston cavity, a first-level accommodating cavity is arranged at the lower end of the first-level plunger, a first-level oil control disk is slidably arranged in the first-level accommodating cavity, a first-level spring is arranged between the first-level oil control disk and the first-level one-way valve, and a first-level oil drain hole connected with the first-level accommodating cavity is opened at the top of the first-level plunger.

[0013] Further improvement, a secondary accommodating chamber is provided at the lower end of the secondary plunger, a secondary oil control plate is slidably provided in the secondary accommodating chamber, a secondary spring is provided between the secondary oil control plate and the bottom of the secondary piston chamber, and a secondary oil drain hole connected to the secondary accommodating chamber is opened at the top of the secondary plunger.

[0014] As a further improvement, two positioning frames are arranged on the top of the shell, positioning holes are provided on the two positioning frames, and limiting plug plates for simultaneously axially limiting the primary plunger and the secondary plunger are detachably inserted in the two positioning holes.

[0015] Further improved, a plurality of vertically distributed arc grooves are provided on the outer wall of the first-stage plunger near the opening end of the first-stage piston chamber, and a ratchet retaining spring is installed in the arc groove; a limiting groove is provided on the inner wall of the first-stage piston chamber near the opening end, and the outer ring of the ratchet retaining spring is slidably installed in the limiting groove.

[0016] In a further improvement, a receiving groove for receiving the ratchet spring is provided on the outer wall of the first-stage plunger away from the bottom of the first-stage piston chamber. In the above improved structure, the receiving groove is provided to facilitate the assembly of the ratchet spring. During the assembly process, the ratchet spring is retracted and received in the receiving groove in advance, so that the first-stage plunger can be smoothly installed into the first-stage piston chamber. When the ratchet spring moves downward to the position of the limiting groove, the ratchet spring is released and rebounds in the limiting groove to limit the axial movement stroke of the first-stage plunger.

[0017] Other improved features and advantages of the utility model will be described in the subsequent specific embodiments, and partly become apparent from the description, or understood by implementing the utility model. The purpose and other advantages of the utility model can be achieved and obtained through the structures specifically pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a three-dimensional structural diagram of a double plunger tensioner with a sealing ring of the utility model;

[0019] Figure 2 It is a cross-sectional view of a double plunger tensioner with a sealing ring of the utility model;

[0020] Figure 3 for Figure 2 The X in the figure is a magnified structural diagram;

[0021] Figure 4 Another perspective structural diagram of the double plunger tensioner with a sealing ring of the utility model;

[0022] Figure 5 This is a structural diagram of a primary plunger in the utility model;

[0023] Figure 6 It is a structural diagram of the sealing ring in the utility model;

[0024] Figure 7 Another structural diagram of the sealing ring in the utility model;

[0025] Figure 8 This is another structural diagram of the sealing ring in the utility model.

[0026] Description of reference numerals:

[0027] 1. Shell; 2. Oil inlet; 3. Fitting groove; 4. Sealing ring; 5. Opening; 6. Primary piston chamber; 7. Secondary piston chamber; 8. Primary plunger; 9. Secondary plunger; 10. Primary one-way valve; 11. Secondary one-way valve; 12. Primary accommodating chamber; 13. Primary oil control plate; 14. Primary spring; 15. Primary oil drain hole; 16. Secondary accommodating chamber; 17. Secondary oil control plate; 18. Secondary spring; 19. Secondary oil drain hole; 20. Positioning frame; 21. Positioning socket; 22. Limiting plug plate; 23. Arc-shaped slot; 24. Ratchet retaining spring; 25. Limiting groove; 26. Accommodating groove; 27. Low-pressure chamber; 28. Bending section. DETAILED DESCRIPTION

[0028] First, those skilled in the art should understand that these implementations are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0029] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "fixed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0030] The present application is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] See also Figures 1 to 8As shown, the embodiment of the present application discloses a double plunger tensioner with a sealing ring, including a housing 1, a mounting cavity with an opening 5 at one end, a plunger slidably mounted in the mounting cavity, a one-way valve between the bottom of the mounting cavity and the lower end of the plunger, an oil inlet 2 connected to the bottom of the mounting cavity at the lower end of the housing 1; a concave oil return cavity at the lower end of the plunger, and an oil drain hole connected to the oil return cavity on the top end face of the plunger. The plunger head supports the guide rail and chain in the chain system; when working, it reciprocates back and forth under the action of hydraulic pressure and spring force, and bears the load transmitted by the chain system.

[0032] In this embodiment, see the attached Figure 2 and 4 The installation chamber includes a primary piston chamber 6 and a secondary piston chamber 7. A primary plunger 8 is installed in the primary piston chamber 6, and a secondary plunger 9 is installed in the secondary piston chamber 7. A low-pressure chamber 27 is arranged on the back of the housing 1. Both the primary piston chamber 6 and the secondary piston chamber 7 are connected to the low-pressure chamber 27. A primary check valve 10 is installed between the primary piston chamber 6 and the low-pressure chamber 27, and a secondary check valve 11 is installed between the secondary piston chamber 7 and the low-pressure chamber 27. Specifically, the primary check valve 10 is located at the bottom of the primary piston chamber 6, a primary accommodating chamber 12 is arranged at the lower end of the primary plunger 8, a primary oil control plate 13 is slidably arranged in the primary accommodating chamber 12, a primary spring 14 is arranged between the primary oil control plate 13 and the primary check valve 10, and a primary oil drain hole 15 connected to the primary accommodating chamber 12 is opened on the top of the primary plunger 8. In addition, oil circuits with different groove depth specifications are arranged on the top of the primary oil control plate 13 to adjust the head oil drain speed and change the hydraulic stiffness and damping of the tensioner.

[0033] A secondary accommodating chamber 16 is provided at the lower end of the secondary plunger 9, a secondary oil control plate 17 is slidably provided in the secondary accommodating chamber 16, a secondary spring 18 is provided between the secondary oil control plate 17 and the bottom of the secondary piston chamber 7, and a secondary oil drain hole 19 connected to the secondary accommodating chamber 16 is opened at the top of the secondary plunger 9.

[0034] In the above structure, compared with the traditional single-piston double-plunger tensioner with a sealing ring, the primary spring 14 and the secondary spring 18 of the dual-piston tensioner are both low-rigidity springs. When the engine is starting, idling or running at low speed, the preload force provided by the two low-rigidity mechanical springs of the dual-piston tensioner is small, which effectively reduces the chain tension, thereby eliminating unnecessary torque loss of the engine under low load. When the engine runs to a high-speed state, since the secondary piston chamber 7 is smaller and responds to the oil pressure faster, the secondary piston will be quickly pumped up under the action of the oil pressure, and the pumped-up secondary piston will compress the high-rigidity spring assembly on the moving guide rail, thereby quickly increasing the tensioning force and realizing system control under high load. As an important matching component of the dual-piston tensioner, the high-rigidity spring assembly can provide different spring forces under different working conditions. Therefore, the dual-piston tensioner is also called a variable force tensioner.

[0035] In addition, see Appendix Figure 1 , two positioning frames 20 are arranged on the top of the housing 1, and positioning holes 21 are provided on the two positioning frames 20, and the two positioning holes 21 are detachably inserted with limiting plugs 22 for simultaneously axially limiting the primary plunger 8 and the secondary plunger 9. Specifically, a limiting step is arranged on the outer wall of the upper end of the primary plunger 8, and after the limiting plug 22 is inserted, its two sides are simultaneously pressed on the limiting step and the top of the secondary plunger 9 to achieve axial limiting. The limiting plug 22 here is mainly used in the stage after the product is assembled and before it is installed on the guide rail bracket to prevent the plunger from being separated from the piston cavity under the action of the spring. Specifically, after the double-piston double-piston tensioner with a sealing ring is assembled with the guide rail bracket, the limiting plug 22 can be pulled out of the positioning hole 21 by pulling the bending section 28 at one end thereof. After the limiting plug 22 is pulled out, the outer end of the primary piston and the outer end of the secondary piston are respectively abutted and matched with the corresponding components.

[0036] In this embodiment, more importantly, see the attached Figure 2 , a skirt sealing section is provided at the lower end of the primary plunger 8 and the secondary plunger 9, and a sealing ring 4 is installed between the outer wall of the skirt sealing section of the primary plunger 8 and the inner wall of the primary piston chamber 6, and an axially connected opening 5 is provided on the side wall of the sealing ring 4 to form an oil leakage channel, and the radial dimension of the sealing ring 4 can be self-adjusted under the action of oil pressure. After such arrangement, after the oil is introduced into the primary piston chamber 6, the radial dimension of the sealing ring 4 expands outward under the action of oil pressure, ensuring the sealing cooperation between the primary plunger 8 and the piston chamber, and the oil at the lower end of the primary piston chamber 6 can only be discharged through the oil leakage channel formed by the position of the opening 5, reducing the flow change caused by temperature and oil pressure changes. Compared with conventional tensioners, the tensioner in this embodiment has better performance in terms of system control of noise and vibration through the arrangement of the sealing ring 4 structure, and thus has broader application prospects.

[0037] In this embodiment, see the attached Figure 3A fitting groove 3 is concavely provided on the outer wall of the skirt sealing section of the primary plunger 8, and the radial inner end of the sealing ring 4 is fitted in the fitting groove 3. The width of the fitting groove 3 is greater than the width of the sealing ring 4. Specifically, the height difference between the sealing ring 4 and the fitting groove 3 is 0.5 to 1 mm. In addition, the radial outer end of the sealing ring 4 is close to the inner wall of the primary piston chamber 6. When the oil is drained during operation, under the action of oil pressure, the sealing ring 4 moves upward to its top and abuts against the fitting groove 3, so that a first channel is formed between the lower end face of the sealing ring 4 and the lower end face of the fitting groove 3; and at the same time, the sealing ring 4 radially expands outward until its outer wall is sealed against the inner wall of the primary piston chamber 6. At this time, a gap is left between the inner side wall of the sealing ring 4 and the radial inner wall of the fitting groove 3 to form a second channel, and the second channel is used to connect the first channel with the oil drain channel, so that the oil in the primary piston chamber 6 passes through the first channel and the second channel once and then flows out from the oil drain channel; in addition, the radial gap between the sealing ring 4 and the second channel is 0.1-1 mm.

[0038] In some other embodiments, a fitting groove 3 may be opened on the inner wall of the primary piston chamber 6, or an inner groove may be opened on both the outer wall of the skirt sealing section of the primary plunger 8 and the inner wall of the primary piston chamber 6, and the two inner grooves together constitute the fitting groove 3.

[0039] In the above structure, the diameter of the sealing ring 4 is 8-20 mm, the width is 0.1-10 mm, and the thickness is 0.1-3 mm. The material of the sealing ring 4 includes wear-resistant materials such as steel, copper, rubber, and plastic. By replacing the sealing ring 4 of different specifications, there are more options for adjusting the performance of the tensioner, and even the use of cam parts and guide rails in the chain system can be reduced, thereby reducing the system cost.

[0040] In this structure, the change of flow rate can be controlled by the size of the opening 5 on the sealing ring 4, thereby changing the hydraulic stiffness and damping of the tensioner to achieve system control; at the same time, changes in temperature and oil pressure will no longer affect the change of flow rate, and the system will maintain constant performance. In the above structure, preferably, the height difference between the sealing ring 4 and the fitting groove 3 is 0.5 to 1 mm. In this structure, the height difference between the sealing ring 4 and the fitting groove 3 is set in a reasonable range, so that the sealing ring 4 has a relatively movable gap, so that it can better adapt to changes in temperature and oil pressure, thereby better ensuring the sealing performance.

[0041] On the other hand, in this embodiment, see the attached Figure 5A plurality of vertically distributed arc-shaped grooves 23 are provided on the outer wall of the primary plunger 8 near the opening 5 of the primary piston chamber 6, and a ratchet retaining spring 24 is installed in the arc-shaped groove 23; a limiting groove 25 is provided on the inner wall of the primary piston chamber 6 near the opening 5, and the outer ring of the ratchet retaining spring 24 is slidably installed in the limiting groove 25; and a receiving groove 26 for receiving the ratchet retaining spring 24 is provided on the outer wall of the primary plunger 8 away from the bottom of the primary piston chamber 6. In the structure of this embodiment, due to the existence of the sealing ring 4 structure, it is not suitable for the conventional installation method of pre-installing the ratchet retaining spring 24 in the limiting groove 25 position and then pressing the primary plunger 8. Therefore, the accommodating groove 26 structure in the above structure is for facilitating the assembly of the ratchet retaining spring 24. During the assembly process, the ratchet retaining spring 24 is retracted and accommodated in the accommodating groove 26 in advance, so as to facilitate the smooth installation of the primary plunger 8 into the primary piston chamber 6. When the ratchet retaining spring 24 moves downward to the position of the limiting groove 25, the ratchet retaining spring 24 is released and rebounds in the limiting groove 25 to limit the axial movement stroke of the primary plunger 8.

[0042] In addition, see the attached Figure 6 The opening 5 in this embodiment is a vertical opening 5 that vertically penetrates along the axial direction of the sealing ring 4. In some other embodiments, the opening 5 can also be an inclined opening 5 that is inclined along the axial direction of the sealing ring 4, such as Figure 7 or the opening 5 is a right-angle S-shaped structure that passes axially through the sealing ring 4, as shown Figure 8 As shown, different flow rates can be adjusted by setting the openings 5 ​​in different structures; in the above structure, no matter which structure the openings 5 ​​are, the spacing between the openings 5 ​​is 0-5 mm, so as to reasonably control the gap leakage. In some other embodiments, multiple sealing rings can also be used to achieve similar functions.

[0043] In the description of the present application, the description with reference to the terms "present embodiment", "some embodiments", etc. means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradicting each other.

[0044] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A double plunger tensioner with a sealing ring, comprising a housing (1), the housing (1) being provided with a mounting cavity with an opening (5) at one end, a plunger being slidably mounted in the mounting cavity, the housing (1) being provided with an oil inlet (2) communicating with the closed end of the mounting cavity, characterized in that: An annular fitting groove (3) is concavely arranged on the outer wall of the skirt sealing section of the plunger and / or the inner wall of the mounting cavity, a sealing ring (4) is installed in the fitting groove (3), and the width of the fitting groove (3) is greater than the width of the sealing ring (4); an axially connected opening (5) is arranged on the side wall of the sealing ring (4) to form an oil leakage channel, and the radial dimension of the sealing ring (4) can be self-adjusted under the action of oil pressure; the diameter of the sealing ring (4) is 8 to 20 mm, the width is 0.1 to 10 mm, the thickness is 0.1 to 3 mm, and the spacing at the opening (5) is 0 to 5 mm.

2. The double plunger tensioner with a sealing ring according to claim 1, characterized in that: The height difference between the sealing ring (4) and the fitting groove (3) is 0.5 to 1 mm, and the radial clearance between the sealing ring (4) and the fitting groove (3) is 0.1 to 1 mm.

3. The double plunger tensioner with a sealing ring according to claim 1, characterized in that: The opening (5) is a vertical opening (5) that vertically penetrates along the axial direction of the sealing ring (4), or an inclined opening (5) that obliquely penetrates along the axial direction of the sealing ring (4), or a right-angle S-shaped opening (5) that penetrates along the axial direction of the sealing ring (4).

4. The double plunger tensioner with a sealing ring according to any one of claims 1 to 3, characterized in that: The installation chamber comprises a primary piston chamber (6) and a secondary piston chamber (7), wherein a primary plunger (8) is installed in the primary piston chamber (6), and a secondary plunger (9) is installed in the secondary piston chamber (7), and the sealing ring (4) is arranged between the outer wall of the primary plunger (8) and the inner wall of the piston chamber; a low-pressure chamber (27) is arranged on the housing (1), and the primary piston chamber (6) and the secondary piston chamber (7) are both connected to the low-pressure chamber (27), a primary check valve (10) is installed between the primary piston chamber (6) and the low-pressure chamber (27), and a secondary check valve (11) is installed between the secondary piston chamber (7) and the low-pressure chamber (27).

5. The double plunger tensioner with a sealing ring according to claim 4, characterized in that: The primary one-way valve (10) is located at the bottom of the primary piston chamber (6); a primary accommodating chamber (12) is provided at the lower end of the primary plunger (8); a primary oil control plate (13) is slidably provided in the primary accommodating chamber (12); a primary spring (14) is provided between the primary oil control plate (13) and the primary one-way valve (10); and a primary oil drain hole (15) communicating with the primary accommodating chamber (12) is provided at the top of the primary plunger (8).

6. The double plunger tensioner with a sealing ring according to claim 5, characterized in that: A secondary accommodating chamber (16) is arranged at the lower end of the secondary plunger (9), a secondary oil control plate (17) is slidably arranged in the secondary accommodating chamber (16), a secondary spring (18) is arranged between the secondary oil control plate (17) and the bottom of the secondary piston chamber (7), and a secondary oil drain hole (19) communicating with the secondary accommodating chamber (16) is opened at the top of the secondary plunger (9).

7. The double plunger tensioner with a sealing ring according to claim 6, characterized in that: Two positioning frames (20) are arranged on the top of the housing (1), and positioning holes (21) are provided on the two positioning frames (20), and limiting plug plates (22) for simultaneously axially limiting the primary plunger (8) and the secondary plunger (9) are detachably inserted in the two positioning holes (21).

8. The double plunger tensioner with a sealing ring according to claim 6, characterized in that: A plurality of vertically distributed arc-shaped grooves (23) are provided on the outer wall of the first-stage plunger (8) near the opening (5) end of the first-stage piston chamber (6), and a ratchet retaining spring (24) is installed in the arc-shaped groove (23); a limiting groove (25) is provided on the inner wall of the first-stage piston chamber (6) near the opening (5), and the outer ring of the ratchet retaining spring (24) is slidably installed in the limiting groove (25).

9. The double plunger tensioner with a sealing ring according to claim 8, characterized in that: An accommodating groove (26) for accommodating the ratchet clamping spring (24) is provided on an outer wall of one end of the primary plunger (8) away from the bottom of the primary piston chamber (6).

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