A ratchet hydraulic tensioner

Abstract

The present invention discloses a ratchet-shaped hydraulic tensioner, comprising a shell, a one-way valve and a piston, wherein the shell has an accommodating chamber, one end of the shell has an oil inlet, one end of the accommodating chamber close to the oil inlet is communicated with the oil inlet, and one end of the accommodating chamber away from the oil inlet is open to the outside of the shell, the one-way valve is fixed in the oil inlet, the piston is accommodated in the accommodating chamber, the piston and the accommodating chamber are clearance-matched, and the piston can reciprocate along the axial direction of the accommodating chamber; the accommodating chamber is provided with a compression spring, one end of the compression spring contacts the piston, and the other end contacts the bottom surface of the accommodating chamber; a locking spring is also included; a ratchet section is provided on the piston, the ratchet section is located at the end of the piston away from the compression spring, and the locking spring contacts the ratchet section, so that the piston can only move in the direction away from the compression spring.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic tensioners, and in particular relates to a ratchet hydraulic tensioner. Background Art

[0002] The tensioner acts on the timing belt or timing chain of the engine, guiding and tightening it, so that it is always in the best tension state. It is generally divided into two ways: hydraulic and mechanical, both of which can automatically adjust the tension of the timing belt and timing chain. The specific distance is: under the transmission of the timing belt or timing chain, the camshaft drives the valve to open and close at the right time, and cooperates with the piston to complete the four processes of intake, compression, power and exhaust. Because the timing belt and timing chain will jump when running at medium and high speeds, and the timing belt will be elongated and deformed in long-term use due to the material and force of the belt, resulting in tooth jumps and inaccurate valve timing, which will cause vehicle fuel consumption, powerlessness, knocking and other faults. When there are too many teeth jumps, the valve will open too early or close too late, and the valve and the upward piston will collide and damage the engine.

[0003] In order to keep the timing belt and timing chain at the appropriate tension, that is, not to jump teeth due to being too loose or to be damaged due to being too tight, there is a special tensioning system consisting of a tensioner and a tensioner wheel or guide rail. The tensioner provides pressure directed to the belt or chain, the tensioner wheel is in direct contact with the timing belt, and the guide rail is in direct contact with the timing chain. They apply the pressure provided by the tensioner to the belt or chain while running with it, so that they maintain the appropriate tension.

[0004] The conventional hydraulic tensioner drives the oil pump to build up a certain oil pressure through the operation of the engine. The oil pressure is passed into the hydraulic tensioner to push out the piston, thereby applying a certain pressure to the belt or chain through the piston, thereby ensuring that the belt or chain is tightened; however, one problem that cannot be overcome is that after the oil pressure disappears after the engine stops, the piston of the hydraulic tensioner will retract into the housing under the push of the belt or chain. It takes a certain amount of time for the oil pump to start rotating and build up sufficient oil pressure when the engine stops and starts again. In other words, during the period from the start of the engine to normal operation and the establishment of sufficient oil pressure, the piston of the hydraulic tensioner will hardly extend to apply sufficient pressure to the belt or chain, that is, it is difficult to ensure that the belt or chain has sufficient tension, which is very likely to cause the problem of tooth skipping and inaccurate valve timing. Summary of the invention

[0005] The purpose of the present invention is to provide a ratchet hydraulic tensioner, which solves the technical problems existing in the background technology.

[0006] To solve the above technical problems, the purpose of the present invention is achieved as follows:

[0007] A ratchet hydraulic tensioner comprises a housing, a one-way valve and a piston, wherein the housing has a housing chamber, one end of the housing has an oil inlet, one end of the housing chamber close to the oil inlet is connected to the oil inlet, and one end of the housing chamber away from the oil inlet is open to the outside of the housing, the one-way valve is fixed in the oil inlet, the piston is accommodated in the housing chamber, the piston and the housing chamber are clearance-matched, and the piston can reciprocate along the axial direction of the housing chamber; a compression spring is arranged in the housing chamber, one end of the compression spring contacts the piston, and the other end contacts the bottom surface of the housing chamber;

[0008] It also includes a locking spring; a ratchet section is provided on the piston, the ratchet section is located at the end of the piston away from the compression spring, the locking spring contacts the ratchet section, so that the piston can only move in the direction away from the compression spring.

[0009] On the basis of the above scheme and as a preferred scheme of the above scheme: the ratchet section includes a ratchet-shaped protrusion which is provided on the outer peripheral surface of the piston and has a continuous cross-section.

[0010] On the basis of the above scheme and as a preferred scheme of the above scheme: the locking spring includes a limiting portion, a first elastic portion and a second elastic portion, the limiting portion is embedded between two adjacent ratchet-shaped protrusions of the ratchet segment, the first elastic portion and the second elastic portion maintain a trend force applied to the limiting portion, and the trend force keeps the limiting portion in contact with the ratchet segment.

[0011] On the basis of the above scheme and as a preferred scheme of the above scheme: the limiting portion includes two symmetrically arranged limiting edges, and the limiting edges are semicircular arc-shaped.

[0012] On the basis of the above scheme and as a preferred scheme of the above scheme: the first elastic part and the second elastic part are both U-shaped structures, the locking spring is bent into an integral body, and the two free ends after bending are located at the U-shaped bottom of the second elastic part.

[0013] On the basis of the above solution and as a preferred solution of the above solution: the shell is symmetrically provided with buckles, and the first elastic part and the second elastic part are buckled into two of the buckles respectively.

[0014] On the basis of the above scheme and as a preferred scheme of the above scheme: it also includes a locking pin, which restricts the piston in the accommodating chamber before assembly, and at this time each of the buckles has a minimum distance a from the corresponding U-shaped bottom of the first elastic part and the second elastic part.

[0015] On the basis of the above scheme and as a preferred scheme of the above scheme: the interior of the piston is hollow, and the piston is open at one end toward the compression spring, and an exhaust hole is opened at the other end, a filler is provided inside the piston, the end of the compression spring enters into the interior of the piston and is sleeved outside the filler, the filler has an enlarged end at the end away from the compression spring, the compression spring is in contact with the enlarged end, so that the enlarged end is in contact with the piston.

[0016] Compared with the prior art, the present invention has the following outstanding and beneficial technical effects: the ratchet segment on the piston is limited and locked by the locking spring, so that in the first engine working state, after the oil pump establishes the oil pressure required for work, the piston extends a sufficient length to apply sufficient pressure to the belt or chain, so that the belt or chain obtains sufficient tension; in the process of piston extension, the limiting portion of the locking spring will jump over multiple ratchet teeth in the ratchet segment, and will lock the ratchet segment after jumping; even when the engine stops and the oil pressure disappears, the locking spring will limit the piston from retracting inwards; that is, due to the presence of the locking spring, the piston can only extend out of the accommodating cavity but cannot retract In this way, at the initial stage of restarting the engine, since the extended length of the piston remains the same as the length when it stopped last time, the hydraulic tensioner can still apply sufficient pressure to the belt or chain, thereby avoiding the problem of inaccurate valve timing caused by the belt or chain jumping caused by the traditional hydraulic tensioner at the initial stage of engine startup; in addition, as the timing system is used for a longer time, the length of the belt and chain will be lengthened, so in order to ensure a constant tension on the belt or chain, the piston of the hydraulic tensioner will be further extended, and the extended length of the piston can still be maintained through the action of the locking spring, so that sufficient tension can be guaranteed every time the engine is started. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a three-dimensional schematic diagram of the overall structure of the present invention;

[0018] Figure 2 It is a schematic diagram of the overall structure of the present invention;

[0019] Figure 3 It is a schematic diagram of the matching structure of the locking spring and the ratchet segment;

[0020] Figure 4 It is the AA section view;

[0021] Figure 5 is a three-dimensional schematic diagram of the locking spring structure;

[0022] Figure 6 is a schematic diagram of the locking spring structure;

[0023] Figure 7 It is a schematic diagram of the structure of the piston in its initial state;

[0024] Figure 8 It is a structural diagram of the piston in the extended state. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of this application clearer, the technical solution in the embodiment will be clearly and completely described below in conjunction with the drawings in the embodiment. Obviously, the described embodiment is only a part of the embodiment of this application, not all embodiments. Based on the given embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0026] In the description of the present application, it should be understood that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0027] In the description of this application, the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0028] A ratchet hydraulic tensioner comprises a housing 1, a one-way valve 2 and a piston 3. The housing 1 has an accommodating chamber 11. One end of the housing 1 has an oil inlet 12. The end of the accommodating chamber 11 close to the oil inlet 12 is connected to the oil inlet 12. The end of the accommodating chamber 11 away from the oil inlet 12 is open to the outside of the housing 1. The one-way valve 2 is fixed in the oil inlet 12. The piston 3 is accommodated in the accommodating chamber 11. The piston 3 and the accommodating chamber 11 are gap-matched, so that an oil leakage gap is formed through this gap. The piston 3 can reciprocate along the axial direction of the accommodating chamber 11. A compression spring 4 is provided in the accommodating chamber 11. One end of the compression spring 4 contacts the piston 3, and the other end contacts the bottom surface of the accommodating chamber 11. The compression spring forms an initial preset pressure of the hydraulic tensioner.

[0029] It also includes a locking spring 8; the piston 3 is provided with a ratchet section 31, the ratchet section 31 is located at the end of the piston 3 away from the compression spring 4, and the locking spring 8 is in contact with the ratchet section 31, so that the piston 3 can only move in the direction away from the compression spring 4. Specifically, in this embodiment, the ratchet section 31 includes a ratchet-shaped protrusion provided on the outer peripheral surface of the piston 3 and having a continuous cross-section. The locking spring includes a limiting portion 81, a first elastic portion 82 and a second elastic portion 83. The limiting portion 81 is embedded between two adjacent ratchet-shaped protrusions of the ratchet section 31. The first elastic portion 82 and the second elastic portion 83 keep applying a tendency force to the limiting portion 81, and the tendency force keeps the limiting portion 81 in contact with the ratchet section 31. It is further preferred that the limiting portion 81 includes two symmetrically arranged limiting edges 811, and the limiting edges 811 are semicircular arcs. The first elastic portion 82 and the second elastic portion 83 are both U-shaped structures. The locking spring 8 is bent and formed as one piece, and the two free ends 831 after bending are located at the U-shaped bottom of the second elastic portion 83 .

[0030] In addition, the present embodiment also preferably has the shell 1 symmetrically provided with buckles 13, and the first elastic portion 82 and the second elastic portion 83 are respectively buckled into the two buckles 13, so that the first elastic portion and the second elastic portion are restricted by the buckles 13, so that the limiting portion 81 does not move with the piston 3, so that when the piston 3 is extended, the ratchet section 31 can move relative to the limiting edge 811, so that the county party committee section 811 jumps over multiple ratchets, thereby locking the piston at the current extended length.

[0031] In order to prevent the piston 3 of the hydraulic dual-piston tensioner from falling out of the housing 1 and being lost during transportation, the present embodiment preferably also includes a locking pin 6. Before assembly, the locking pin 6 restricts the piston 3 in the accommodating chamber 11, and at this time, each buckle 13 has a minimum distance a from the corresponding U-shaped bottom of the first elastic part 82 and the second elastic part 83.

[0032] The interior of the piston 3 is hollow, and one end of the piston 3 is open toward the compression spring 4, and the other end is provided with an exhaust hole 7. A filler 5 is provided inside the piston 3, and the end of the compression spring 4 enters into the interior of the piston 3 and is sleeved outside the filler 5. The end of the filler 5 away from the compression spring 4 has an enlarged end, and the compression spring 4 contacts the enlarged end so that the enlarged end contacts the piston 3.

[0033] The working principle of this embodiment is as follows: during operation, the engine oil is filled into the oil inlet 12 through the main oil channel of the engine, and then filled into the accommodating chamber 11 through the one-way valve 2. When the chain load force is applied to the piston 3, the compression spring 4 in the piston 3 is compressed, and then the piston 3 moves along the inner cavity of the accommodating chamber 11 toward the end where the one-way valve 2 is located. The engine oil in the piston 3 is squeezed to form a higher oil pressure, and will gradually flow out from the oil leakage gap. At the same time, the bubbles in the engine oil are discharged through the exhaust hole 7 to avoid affecting the establishment of the oil pressure in the piston 3, and finally form a damping for the load force of the chain, so that the timing chain system can operate stably; at the same time, the one-way valve 2 will be opened and closed due to the change of the oil pressure difference, controlling the flow of engine oil on both sides of the valve body. When the engine oil in the piston 3 is leaked, the oil pressure is reduced, so that the one-way valve 2 is opened, and the engine oil will be filled into the accommodating chamber from the main oil channel of the engine again to form oil pressure. In this way, the oil filling is circulated, so that the integrated hydraulic double-piston tensioner can operate cyclically. In the above working process, the locking spring will limit and lock the ratchet section on the piston, so that in the first engine working state, after the oil pump establishes the oil pressure required for work, the piston extends a sufficient length to apply sufficient pressure to the belt or chain, so that the belt or chain obtains sufficient tension. In the process of piston extension, the limiting part of the locking spring will jump over multiple ratchet teeth in the ratchet section and lock the ratchet section after jumping. Even when the engine stops and the oil pressure disappears, the locking spring will limit the piston from retracting inward. That is to say, due to the existence of the locking spring, the piston can only extend out of the accommodating cavity but cannot retract. At the beginning of the engine restart, since the extended length of the piston remains the same as the length when it stopped last time, the hydraulic tensioner can still apply sufficient pressure to the belt or chain, thereby avoiding the problem of inaccurate valve timing caused by the belt or chain jumping caused by the traditional hydraulic tensioner at the beginning of the engine startup; in addition, as the timing system is used for a longer time, the length of the belt and chain will be lengthened. In order to ensure a constant tension on the belt or chain, the piston of the hydraulic tensioner will be further extended. The extended length of the piston can still be maintained through the action of the locking spring, so sufficient tension can be guaranteed every time the engine is started.

[0034] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A ratchet hydraulic tensioner, characterized in that: The invention comprises a housing (1), a one-way valve (2) and a piston (3), wherein the housing (1) has a receiving chamber (11), one end of the housing (1) has an oil inlet (12), one end of the receiving chamber (11) close to the oil inlet (12) is connected to the oil inlet (12), and one end of the receiving chamber (11) away from the oil inlet (12) is open to the outside of the housing (1), the one-way valve (2) is fixed in the oil inlet (12), the piston (3) is received in the receiving chamber (11), the piston (3) and the receiving chamber (11) are clearance-matched, and the piston (3) can reciprocate along the axial direction of the receiving chamber (11); a compression spring (4) is provided in the receiving chamber (11), one end of the compression spring (4) is in contact with the piston (3), and the other end is in contact with the bottom surface of the receiving chamber (11); It also includes a locking spring (8); a ratchet section (31) is provided on the piston (3), the ratchet section (31) is located at an end of the piston (3) away from the compression spring (4), and the locking spring (8) is in contact with the ratchet section (31), so that the piston (3) can only move in a direction away from the compression spring (4); The ratchet segment (31) comprises a ratchet-shaped protrusion which is provided on the outer peripheral surface of the piston (3) and has a continuous cross section; The locking spring comprises a limiting portion (81), a first elastic portion (82) and a second elastic portion (83); the limiting portion (81) is embedded between two adjacent ratchet-shaped protrusions of the ratchet segment (31); the first elastic portion (82) and the second elastic portion (83) keep applying a tendency force to the limiting portion (81), and the tendency force keeps the limiting portion (81) in contact with the ratchet segment (31); The limiting portion (81) comprises two symmetrically arranged limiting edges (811), and the limiting edges (811) are semicircular arc-shaped; The first elastic portion (82) and the second elastic portion (83) are both U-shaped structures, the locking spring (8) is formed by bending in one piece, and the two free ends (831) after bending are located at the bottom of the U shape of the second elastic portion (83); The housing (1) is symmetrically provided with buckles (13), and the first elastic portion (82) and the second elastic portion (83) are buckled into two of the buckles (13) respectively; It also includes a locking pin (6) which, before assembly, restricts the piston (3) within the accommodating chamber (11), and at this time, each of the buckles (13) has a minimum distance (a) from the corresponding U-shaped bottom of the first elastic portion (82) and the second elastic portion (83).

2. The ratchet hydraulic tensioner according to claim 1, characterized in that: The interior of the piston (3) is hollow, and one end of the piston (3) is open toward the compression spring (4), and the other end is provided with an exhaust hole (7). A filler (5) is provided inside the piston (3), and the end of the compression spring (4) enters the interior of the piston (3) and is sleeved outside the filler (5). The end of the filler (5) away from the compression spring (4) has an enlarged end, and the compression spring (4) is in contact with the enlarged end, so that the enlarged end is in contact with the piston (3).

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