A double-spring hydraulic tensioner

Abstract

The present invention discloses a double-spring hydraulic tensioner, which includes a housing, a plunger, a plunger spring, a one-way valve, and a pressure relief valve; a spring buffer compensation mechanism is provided at the top of the plunger, the pressure relief valve is assembled at the top of the inner cavity of the plunger, the plunger spring is sleeved outside the pressure relief valve, and the upper end of the plunger spring abuts against the lower end surface of the pressure relief valve; a buffer mechanism is provided at the top end of the plunger, and the plunger and the buffer mechanism are communicated through an oil outlet hole; the buffer mechanism contacts the vibrating object. The variable pitch compression spring is used to replace the ordinary spring in the hydraulic chamber. At the same time, through the cooperation of the variable pitch compression spring and the buffer mechanism at the top of the plunger, not only can the spring force required by the system be provided, but also the useless frictional work of the system can be reduced, and the situation that the plunger cannot pop out in time due to negative pressure to cause abnormal noise in the engine can be avoided; in this application, by using a large-flow one-way valve, a damping force can be quickly formed, so that the buffer mechanism and the tensioner body can provide a better tension force for the vibrating object.

Description

Technical Field

[0001] The present invention provides a hydraulic tensioner, and particularly relates to a double-spring hydraulic tensioner. Background Art

[0002] In the past, in transmission media such as timing chains that rotate between the crankshaft and the camshaft of a vehicle engine, in order to suppress vibrations generated during their operation and maintain appropriate tension, hydraulic tensioners have been widely used.

[0003] Traditional hydraulic tensioners include a housing with a cylindrical hole, a plunger that can slide in the cylindrical hole and one end of which protrudes from an opening, and a plunger spring that presses the plunger in the protruding direction. The housing and the plunger together form a high-pressure oil storage chamber, and a check valve mechanism including a metal cylinder is installed in the cylindrical hole of the housing so that oil can enter the high-pressure oil storage chamber to form damping, thereby achieving the effect of adjusting the tension of the engine chain.

[0004] When the hydraulic tensioner adjusts the tension of the vibrating object (chain / guide rail), the end of the plunger in the hydraulic tensioner contacts the vibrating object (chain / guide rail) to provide tension. At the same time, in the timing system of the engine, the chain will elongate over time, and the plunger will also elongate accordingly, resulting in a reduction in spring force; and when the tensioner provides a tensioning function, it will provide an interference tensioning force and consume more energy, and due to the negative pressure in the cavity, the plunger of the tensioner and the vibrating object (chain / guide rail) may not pop out in time, resulting in abnormal noises, and causing abnormal noises in the engine. Summary of the Invention

[0005] In summary, in order to optimize the deficiencies in the above background art, a double-spring hydraulic tensioner is now proposed.

[0006] To achieve the above object, the present invention is realized through the following solutions: The present invention is a double-spring hydraulic tensioner, including a housing in which a hydraulic cavity is provided, and an oil inlet passage is provided at the bottom of the hydraulic cavity. The double-spring hydraulic tensioner further includes: a plunger that is telescopically installed in the hydraulic cavity, and the plunger is provided with a cavity opening downward; a plunger spring that is disposed in the cavity of the plunger, and the plunger spring is a variable pitch compression spring; a check valve that is installed at the bottom of the hydraulic cavity, its input end is communicated with the oil inlet passage, and the output end of the check valve contacts one end of the plunger spring, and the check valve is a large-flow check valve; wherein, a pressure relief valve is assembled at the top end of the cavity of the plunger, and the plunger spring is sleeved outside the pressure relief valve, and the upper end of the plunger spring abuts against the lower end surface of the pressure relief valve; a buffer mechanism is provided at the top end of the plunger, and the plunger is communicated with the buffer mechanism through an oil outlet hole; and the buffer mechanism contacts the vibrating object.

[0007] Further, the buffer mechanism includes an extension integrally connected to the top end of the plunger. An accommodation cavity with an upward opening is provided in the extension. At the same time, a secondary spring and a top head are installed in the accommodation cavity. One end of the secondary spring abuts against the bottom of the accommodation cavity, and the other end of the secondary spring abuts against the bottom of the top head; and the top head contacts the vibrating object.

[0008] Further, the accommodation cavity communicates with the oil outlet hole on the plunger. At the same time, the upper end of the accommodation cavity is in a contracted shape and forms an inverted T-shaped accommodation cavity, and the top head is fitted and installed in the accommodation cavity. Among them, an annular clamping groove is provided on the outer part of the lower end of the top head, and a secondary snap ring is sleeved on the annular clamping groove, and the outer side of the secondary snap ring is clamped with the inner wall of the accommodation cavity.

[0009] Further, a snap ring is sleeved on the plunger, and a clamping groove matching the snap ring is provided on the inner wall of the hydraulic cavity.

[0010] Further, the plunger spring is a variable pitch compression spring.

[0011] Further, the pressure relief valve is composed of a valve cap, a base, a spring and a steel ball. At the same time, an oil passage is provided on the valve cap.

[0012] Compared with the prior art, the present invention has the following beneficial effects: using a variable pitch compression spring to replace the ordinary spring in the hydraulic cavity, and at the same time through the cooperation of the variable pitch compression spring and the buffer mechanism at the top of the plunger, not only can the spring force required by the system be provided, but also the useless frictional work of the system can be reduced, and the situation that the plunger cannot pop out in time due to negative pressure to cause abnormal noise in the engine can be avoided; in this application, by using a large-flow one-way valve, a damping force can be quickly formed, so that the buffer mechanism and the tensioner body can provide a better tension force for the vibrating object. Description of the Drawings

[0013] Figure 1 It is a schematic cross-sectional structure diagram of this application.

[0014] Figure 2 It is a schematic cross-sectional view of the contact between the tensioner of this application and the guide rail and a partial enlarged view.

[0015] Figure 3 It is a schematic front view of the actual application of this application.

[0016] Figure 4 It is a schematic cross-sectional structure diagram of the pressure relief valve in this application and a top view of the pressure relief valve.

[0017] Figure 5 It is a schematic diagram of the comparison of the oil pressure-flow curve between the one-way valve applied in this application and the one-way valve in ordinary application.

[0018] Figure 6 It is a schematic diagram of the comparison of the hysteresis curves between this application and an ordinary tensioner.

[0019] Figure 7 This is a comparison of the deformation-spring force between the spring (variable pitch compression spring) applied in the hydraulic cavity of this application and an ordinary spring chain.

[0020] Reference signs: housing 10, hydraulic cavity 11, one-way valve 12, plunger spring 13, oil inlet passage 14, clamping groove 15, snap ring 16;

[0021] plunger 20, cavity 21, pressure relief valve 22, oil outlet hole 23, valve cap 220, base 221, spring 222, steel ball 223, oil passage 220a;

[0022] buffer mechanism 30, extension part 30a, accommodating cavity 31, top head 32, annular clamping groove 32a, secondary snap ring 32b, secondary spring 33; vibrating object 40. Detailed implementation manners

[0023] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific embodiments. Those of ordinary skill in the art will be able to implement the invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are usually only some embodiments of the present invention, rather than all embodiments. Therefore, all other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention should fall within the scope of protection of the present invention.

[0024] An embodiment of the present invention is as follows. As an embodiment of the present invention, refer to Figure 1 , Figure 2 , Figure 3 As shown, in this embodiment, the present invention is a double-spring type hydraulic tensioner, including a housing 10, a plunger 20, a plunger spring 13, a one-way valve 12, a pressure relief valve 22 and a buffer mechanism 30.

[0025] Among them, specifically referring to Figure 1 As shown, a hydraulic cavity 11 is provided in the housing 10. An oil inlet passage 14 is provided at the bottom of the hydraulic cavity 11. The plunger 20 is telescopically installed in the hydraulic cavity 11, and the plunger 20 is provided with a cavity 21 opening downward; the plunger spring 13 is arranged in the cavity 21 of the plunger 20, and the plunger spring is a variable pitch compression spring; the one-way valve 12 is installed at the bottom of the hydraulic cavity 11, its input end is communicated with the oil inlet passage 14, and the output end of the one-way valve 12 contacts one end of the plunger spring 13, and this one-way valve is a large-flow one-way valve; among them, a pressure relief valve 22 is assembled at the top end of the cavity 21 of the plunger 20, and the plunger spring 13 is sleeved outside the pressure relief valve 22, and the upper end of the plunger spring 13 abuts against the lower end surface of the pressure relief valve 22; a buffer mechanism 30 is provided at the top end of the plunger 20, and the plunger 20 and the buffer mechanism 30 are communicated through an oil outlet hole 23; and the buffer mechanism 30 contacts the vibrating object 40.

[0026] Reference Figure 1 As shown, in this setting, the buffer mechanism 30 includes an extension 30a integrally connected to the top end of the plunger 20. An accommodation cavity 31 with an upward opening is provided in the extension 30a. At the same time, a secondary spring 33 and a top head 32 are installed in the accommodation cavity 31. One end of the secondary spring 33 abuts against the bottom of the accommodation cavity 30a, and the other end of the secondary spring 33 abuts against the bottom of the top head 32; and the top head 32 is in contact with the vibrating object 40.

[0027] In the above setting, an engaging groove matching the top head 32 can be provided on the contact surface between the vibrating object 40 and the top head 32 in the buffer mechanism 30, and the top head 32 can move in the engaging groove, so that the entire tensioner can provide a good tension force for the vibrating object 40.

[0028] An accommodation cavity 31 for accommodating a spring is added to the top of the plunger, and a top head is placed in the cavity to form a buffer mechanism. If the plunger 20 cannot pop out in time due to negative pressure, the secondary spring 33 at the top of the plunger will supplement the elastic force, so there will be no problem of excessive abnormal noise during the operation of the engine.

[0029] Please combine with Figure 1 , the accommodation cavity 31 communicates with the oil outlet hole 23 on the plunger 20. At the same time, the upper end of the accommodation cavity 31 is in a contracted shape and forms an inverted T-shaped accommodation cavity, and the top head 32 is fitted and installed in the accommodation cavity 31. Among them, an annular clamping groove 32a is provided on the outside of the lower end of the top head 32, and a secondary snap ring 32b is sleeved on the annular clamping groove 32a, and the outside of the secondary snap ring 32b is clamped with the inner wall of the accommodation cavity 31.

[0030] In this embodiment, the top head 32 can be columnar, the upper part of the top head 32 abuts against the vibrating object, and the lower part of the top head 32 is inserted into the accommodation cavity 31. An annular clamping groove 32a is provided on the part of the top head 32 inserted into the accommodation cavity 31 to facilitate the installation of the secondary snap ring 32b. During the use of the buffer mechanism, since the secondary snap ring 32b is clamped with the upper port of the accommodation cavity 31, it can play a limiting effect on the top head 32, thereby ensuring the spring force provided by the buffer mechanism for the system.

[0031] In the above embodiment, specifically refer to Figure 4As shown, the pressure relief valve in the above setting can adjust the flow rate at different oil pressures to balance the operating state of the tensioner during medium and low speed and high speed operation of the engine. The pressure relief valve 22 consists of a valve cap 220, a base 221, a spring 222, and a steel ball 223. At the same time, an oil passage 220a is provided on the valve cap 220. When the hydraulic tensioner provides a tensioning force for the vibrating object, under the action of the pressure relief valve, the hydraulic oil in the hydraulic cavity will spray out from the oil outlet hole and lubricate the components in the buffer mechanism 30 through the oil outlet hole 23. When the oil pressure is low, the oil will flow out from the oil passage. When the oil pressure is high, the spring 222 is compressed, and the oil flows out from the gap between the base 221 and the steel ball 223, greatly enhancing the oil outlet capacity at high oil pressure. The tensioner quickly tightens, reducing the frictional work on the chain.

[0032] At the same time, in the above setting, the spring 222 can adopt a spring with a small force value to reduce the frictional work of the system and save costs.

[0033] In the above embodiment, specifically refer to Figure 5 and the following charts. In this setting, the one-way valve 12 uses a large-flow one-way valve. The pressure in the oil inlet cavity of the tensioner is relatively low. At the same low oil pressure, since the opening flow rate of the large-flow one-way valve is much higher than that of the ordinary one-way valve, in the same cavity, the filling speed of the double-spring hydraulic tensioner is much greater than that of the ordinary tensioner (the initial difference is d). Through the cooperation of the variable pitch compression spring and the plunger end buffer mechanism, the response speed of the hydraulic tensioner in this application is much faster than that of the ordinary tensioner, and the oil pressure in the hydraulic cavity can be quickly established, enabling the hydraulic tensioner to quickly provide a tensioning force for the vibrating object 40 to reduce the noise during the initial start-up of the engine.

[0034]

[0035] In the above embodiment, in combination with Figure 1 , Figure 6 , Figure 7 As shown, in this setting, the plunger spring 13 adopts a variable pitch compression spring. The variable pitch compression spring with a small wire diameter has a smaller spring coefficient when the wire diameter is small. By changing the pitch, the displacement-spring force curve of the spring is changed, making the spring force difference smaller in the initial and chain elongation states of the tensioner, and the tensioning function is more reliable and stable.

[0036] Specifically (refer to the following charts): The spring coefficient is variable, and the variable pitch spring still has sufficient spring force after the chain elongates, enabling the tensioner to have sufficient spring force from the early stage to the later stage of its life.

[0037]

[0038] In the above setting, refer to Figure 6, compared with the existing ordinary tensioner, this application has a more ideal hysteresis curve (the curve of the extension amount of the tensioner and the damping force), and is more sensitive during the compression stroke of the plunger spring (variable pitch compression spring); at the same time, it relies on a large-flow one-way valve to quickly fill with oil, the plunger pops out faster, provides tension force faster, and speeds up the plunger extension time; at the same time, a pressure relief valve is used to quickly drain oil at high pressure, the plunger compresses faster, and speeds up the contraction time; through the cooperation of the variable pitch compression spring, the pressure relief valve and the buffer mechanism, the tensioner of this application has a more flexible hysteresis curve, realizes faster tightening and popping out of the plunger, and faster system response.

[0039] In the above setting, in combination with Figure 1 A circlip 16 is sleeved on the plunger 20, and a card slot 15 cooperating with the circlip 16 is provided on the inner wall of the hydraulic cavity 11.

[0040] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A double-spring hydraulic tensioner, comprising a housing (10) provided with a hydraulic cavity (11) therein. An oil inlet passage (14) is provided at the bottom of the hydraulic cavity (11). Characterized in that it further comprises: A plunger (20) telescopically installed in the hydraulic cavity (11), and the plunger (20) is provided with a cavity (21) opening downward; A plunger spring (13) disposed in the cavity (21) of the plunger (20), and the plunger spring is a variable pitch compression spring; A one-way valve (12) installed at the bottom of the hydraulic cavity (11), its input end communicating with the oil inlet passage (14), and the output end of the one-way valve (12) contacting one end of the plunger spring (13), and the one-way valve is a large-flow one-way valve; Wherein, a pressure relief valve (22) is assembled at the top end of the cavity (21) of the plunger (20), and the plunger spring (13) is sleeved outside the pressure relief valve (22), and the upper end of the plunger spring (13) abuts against the lower end face of the pressure relief valve (22); A buffer mechanism (30) is provided at the top end of the plunger (20), and the plunger (20) communicates with the buffer mechanism (30) through an oil outlet hole (23); And the buffer mechanism (30) contacts a vibrating object (40); The buffer mechanism (30) includes an extension portion (30a) integrally connected to the top end of the plunger (20). An upward-opening accommodation cavity (31) is provided in the extension portion (30a). At the same time, a secondary spring (33) and a top head (32) are installed in the accommodation cavity (31). One end of the secondary spring (33) abuts against the bottom of the accommodation cavity (31), and the other end of the secondary spring (33) abuts against the bottom of the top head (32); And the top head (32) contacts the vibrating object (40); The accommodation cavity (31) communicates with the oil outlet hole (23) on the plunger (20). At the same time, the upper end of the accommodation cavity (31) is in a contracted shape and forms an inverted T-shaped accommodation cavity, and the top head (32) is fitted and installed in the accommodation cavity (31). Wherein, an annular clamping groove (32a) is provided on the outside of the top head (32) near the lower end, and a secondary snap ring (32b) is sleeved on the annular clamping groove (32a), and the outside of the secondary snap ring (32b) is clamped with the inner wall of the accommodation cavity (31).

2. A double-spring hydraulic tensioner according to claim 1, Characterized in that A snap ring (16) is sleeved on the plunger (20), and a clamping groove (15) cooperating with the snap ring (16) is provided on the inner wall of the hydraulic cavity (11).

3. A double-spring hydraulic tensioner according to claim 1, Characterized in that The plunger spring (13) is a variable pitch compression spring.

4. A double-spring hydraulic tensioner according to claim 1, Characterized in that The pressure relief valve (22) is composed of a valve cap (220), a base (221), a spring (222) and a steel ball (223). At the same time, an oil passage (220a) is provided on the valve cap (220).

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