CN222254933U - Hydraulic automatic tensioner and engine system - Google Patents

Abstract

The present application discloses a hydraulic automatic tensioner and an engine system, wherein the tensioner comprises an outer shell, a first cylinder, a second cylinder, a first oil leakage passage and a second oil leakage passage, wherein the outer shell is sleeved on the first cylinder, the second cylinder is used for pressing the chain, and the second cylinder is sleeved on the first cylinder; the first oil leakage passage and the second oil leakage passage are used for connecting the first cavity with the outside, the first oil leakage passage is always connected with the outside, and the second oil leakage passage has a connecting position and a disconnecting position; the second oil leakage passage comprises a first section, the first section passes through the cylinder wall of the first cylinder to form a first opening in the first cavity, and a second opening is formed on the outer peripheral wall of the first cylinder; when the second cylinder moves axially, the second opening can be blocked or opened to switch the second oil leakage passage to the connecting position and the disconnecting position.

Description

Hydraulic automatic tensioner and engine system

Technical Field

The application relates to the technical field of engines, in particular to a hydraulic automatic tensioner and an engine system.

Background

The hydraulic automatic tensioner is used as a core part of an engine chain system and has the functions of tensioning a chain, compensating the abrasion and the extension of the chain, inhibiting the shake of the chain, reducing the dynamic impact of the system and the like. Because the working conditions and load levels of the chain system of the engine are greatly different in different rotating speed ranges and operating conditions, the hydraulic rigidity of the traditional hydraulic automatic tensioner is fixed, so that the hydraulic rigidity of the traditional hydraulic automatic tensioner must be large enough to ensure that the chain can be effectively jacked under the conditions of high speed and heavy load of the engine and certain extreme conditions.

However, because the working conditions and load levels of the chain system are very different between different rotational speed ranges and operating conditions of the engine, the tensioner design is not optimal for the medium and low speed part load conditions which are more common to users, and the friction loss of the chain system is increased and the noise is overlarge due to overlarge rigidity of the tensioner in the medium and low speed part which is more common to users.

In view of this, it is desirable to provide a solution that can ensure that the engine can effectively jack the chain at high speeds and under large loads, and that can reduce friction loss of the chain system and noise of the chain system when the engine is operating at medium and low speeds.

Disclosure of utility model

The application aims to provide a novel technical scheme of a hydraulic automatic tensioner and an engine system, and the structure of the hydraulic automatic tensioner is improved to ensure that an engine can effectively jack a chain at a high speed and under a large load, and meanwhile, when the engine works at a medium-low speed, the friction loss of the chain system can be reduced, and the noise of the chain system is reduced.

The application provides a hydraulic automatic tensioner, which comprises a shell, a first barrel and a second barrel, wherein the shell is sleeved on the first barrel and surrounds a first cavity with the first barrel, the first cavity is used for containing engine oil from an engine, the second barrel is used for pressing a chain, the second barrel is sleeved on the first barrel, the second barrel can move relative to the first barrel in the axial direction under the action of the chain, the first and second oil drain channels are used for enabling the first cavity to be communicated with the outside, the first oil drain channel is always communicated with the outside, the second oil drain channel is provided with a communication station and a disconnection station, the second oil drain channel comprises a first section part, the first section part penetrates through the wall of the first barrel to form a first opening part in the first cavity, a second opening part is formed on the outer peripheral wall of the first barrel, and the second opening part can be switched to be communicated with the second opening station when the second oil drain channel moves in the axial direction.

By adopting the embodiment of the application, the chain tension acts on the second elastic member through the second cylinder body along with the change of the dynamic tension of the chain during the running of the chain system of the engine. The second elastic piece transmits the acting force of the chain to the first barrel so that the first barrel and the second barrel form a movement trend in the same direction.

But is applied to the second elastic member through the first cylinder due to the first cylinder being subjected to the hydraulic pressure from the first chamber and the common thrust of the first elastic member. At this time, the second elastic element is compressed, so that the second cylinder body is displaced relative to the first cylinder body along the axial direction in the direction in which the second elastic element is compressed. When the engine runs at high speed and under large load, the chain load and the tension change are large, the second cylinder body can also displace greatly, when the displacement accords with a set threshold value, the second cylinder body can close the second oil drainage channel, and at the moment, the high-pressure oil in the first cavity can only be drained out through the first oil drainage channel in a normally-open state. The drain rate corresponding to the first chamber is reduced. At this time, the oil in the first chamber will generate a strong resistance support for the first cylinder, and the tensioner operates in a high damping mode. Therefore, when the engine works at high speed and under a large load, the tensioner can effectively push up the chain even if the tension of the chain changes greatly, and the rigidity of the tensioner is high at the moment, so that the chain system can be kept stable in operation.

When the engine works at medium and low speed, the chain works stably, and when the tension change is small, the displacement of the second cylinder body is small at the moment and does not reach the set threshold value. The second oil drainage channel is in a communicated state, and high-pressure engine oil in the first cavity can be drained out of the first oil drainage channel and the second oil drainage channel faster. Thus, the damping of the engine oil in the first cavity to the chain tension is effectively reduced, and the tensioner works in a low damping mode. At this time, the tensioner has small rigidity, namely the tensioner is softer, and the dynamic tension of the chain at this time can be obviously reduced, so that the friction loss of the chain system is reduced, the noise of the chain system is reduced, and the reliability of the chain system is improved. Optionally, the first cylinder is provided with a first end and a second end which are opposite along the axial direction, and the second cylinder is sleeved at the second end.

Optionally, the inner wall of the second cylinder fits the second mouth to block the second mouth, or disengages the second mouth to open the second mouth.

Optionally, the first end is built in the shell, a gap is formed between the second end and the shell in the radial direction, the gap is communicated with the outside, and the second opening is positioned at a part of the first cylinder body surrounding the gap;

The second cylinder moves axially within the gap to open or close the second mouth.

Optionally, the first end is open, the second end is closed, the second cylinder and the second end enclose a second cavity, and the first cavity is spaced from the second cavity;

optionally, a first oil groove communicated with the second opening is formed in the inner wall of the second cylinder, a second oil groove is further formed in the first cylinder, the second oil groove is formed in one side of the second opening, and the first oil groove and the second oil groove are communicated all the time;

The first oil groove and the second oil groove are communicated so as to ensure that the first oil groove can still be communicated with the second opening part when the second cylinder body rotates; an annular groove is formed in the outer wall of the second end of the first cylinder body, corresponding to the second opening, along the circumferential direction, and is used as a second oil groove;

At the disconnection station, the outer wall of the first cylinder body seals the first oil groove;

At the communication station, the first oil groove is communicated with the second cavity.

Optionally, the second cylinder is provided with an oil outlet, and the oil outlet is used for discharging oil and air in the second cavity;

The second cylinder is used for propping against the tensioning rail to compress the chain, and the oil outlet is arranged at the position where the second cylinder contacts with the tensioning rail.

Alternatively, the first drain passage is provided between the first cylinder and the housing, and may be configured to communicate the first chamber with the outside through a suitable fit clearance or by providing a separate slot.

Optionally, the shell is provided with an oil inlet, the tensioner further comprises a one-way valve arranged at the oil inlet, a valve port of the one-way valve is communicated with the oil inlet, the hydraulic automatic tensioner further comprises an oil return channel, and a groove is formed in a contact area between the outer part of the one-way valve and the shell and used for forming bypass connection between the first cavity and the oil inlet to serve as the oil return channel.

Engine oil from the engine can freely enter the inside of the shell from the oil inlet through the one-way valve, and conversely, the one-way valve can prevent the engine oil inside the shell from flowing back to the oil inlet. Similar to the first oil drain channel, a slot or a labyrinth groove may be formed on the outer side wall and the bottom surface of the check valve, which are in contact with the housing, so as to establish a fixed bypass connection between the first cavity and the oil inlet, thereby forming the oil return channel, and the oil return channel is different from the first oil drain channel in that the oil flowing out of the first cavity through the first oil drain channel is directly discharged out of the tensioner, and the oil return channel enables the oil in the first cavity to flow back to the oil inlet, that is, to be recycled inside the tensioner, thereby reducing the oil consumption of the tensioner.

Optionally, the device further comprises a filling part, wherein the filling part is arranged in the first cavity and is connected to one end of the first cylinder close to the second cylinder;

the second oil drainage channel further comprises a second section part with a throttling effect, the second section part is a third oil groove formed in the filling part, one end of the third oil groove is communicated with the first cavity, and the other end of the third oil groove is communicated with the first port part.

Optionally, the third oil groove extends in a spiral shape.

In another aspect of the application, an engine system is provided that includes a chain and the hydraulic automatic tensioner described above that compresses the chain.

Other features of the present specification and its advantages will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and together with the description, serve to explain the principles of the specification.

FIG. 1 is a schematic diagram of the tensioner in combination with a chain in an embodiment of the present application;

FIG. 2 is a schematic diagram of tensioner operation in an embodiment of the present application;

FIG. 3 is a schematic view of a tensioner in a communication station in accordance with a first embodiment of the present application;

FIG. 4 is an enlarged schematic view of the partial structure of FIG. 3;

FIG. 5 is a schematic illustration of a tensioner in a disconnected position in accordance with a first embodiment of the present application;

FIG. 6 is an enlarged schematic view of the partial structure of FIG. 5;

FIG. 7 is a schematic illustration of a tensioner in a second embodiment of the present application in a communication station;

fig. 8 is a schematic view of a tensioner in a second embodiment of the present application in a disconnected position.

Reference numerals illustrate:

1. the device comprises a shell, 11, a gap, 12, an oil inlet, 13, a one-way valve, 14 and an oil return channel;

2. a first cylinder 21, a first end 22, a second end 23, a first elastic member 24, a flange;

3. 31, a first oil drain channel;

4. A second cylinder 41, a second elastic piece 42, a second cavity 43 and an oil outlet;

5. 51, a third oil groove;

6. The second oil drain channel, 61, a first section, 61a, a first opening, 61b, a second opening, 62, a first oil groove, 62a, an oil drain port, 63, a second section, 64, a second oil groove;

7. A tensioner;

8. tensioning the rail;

9. And (3) a chain.

Detailed Description

In order to better understand the aspects of the present application, the present application will be described in further detail with reference to the accompanying drawings and detailed description.

In some embodiments of the present application, as shown in fig. 1 and 2, a hydraulic automatic tensioner 7 is provided, the hydraulic automatic tensioner 7 including a housing 1, a first cylinder 2, and a second cylinder 4. The casing 1 is sleeved on the first cylinder 2 and encloses a first cavity 3 with the first cylinder 2, and the first cavity 3 is used for containing engine oil from an engine. In the case of a turning vehicle engine, oil from the engine enters the first chamber 3 through the oil inlet 12 provided in the housing 1 via the check valve 13 and fills the first chamber 3 to form a high-pressure chamber.

A first elastic member 23 is further disposed between the first cylinder 2 and the housing 1, the first cylinder 2 and the housing 1 are elastically connected through the first elastic member 23, and the first elastic member 23 is configured to provide a resilience force for the first cylinder 2.

As shown in fig. 3, the first cylinder 2 has a first end 21 and a second end 22, the first end 21 being an open end and the second end 22 being a closed end. The first end 21 of the first cylinder 2 is inserted into the housing 1 and defines a first cavity 3 with the inner wall of the housing 1. The oil inlet 12 is arranged on one side of the shell 1. The oil inlet 12 is also communicated with a one-way valve 13 to prevent the oil in the first cavity 3 from flowing back. To adjust the effective volume of the first chamber 3, a corresponding filling portion 5 may be added to the first cylinder 2, the filling portion 5 being connected to the second end 22. A first elastic member 23 is disposed in the first chamber 3, and both ends of the first elastic member 23 are respectively contacted with the housing 1 (or the check valve 13) and the second end 22 (or the filling portion 5) of the first cylinder 2.

As shown in fig. 3, a flange 24 is formed to protrude in the axial direction at the edge of the second end 22 of the first cylinder 2 on the side remote from the first chamber 3.

The second cylinder 4 is used for pressing the tensioning rail 8 and further pressing the chain 9, and the second cylinder 4 is sleeved outside the second end 22 and the flange 24 of the first cylinder 2. The outer wall of the second cylinder 4 is kept at a certain clearance from the inner wall of the housing 1, the inner wall of the second cylinder 4 being matched to the second end 22 of the first cylinder 2 and the outer peripheral wall of the flange 24, the second cylinder 4 being axially movable relative to the first cylinder 2.

Thereby, the second end 22 of the first cylinder 2, the flange 24 and the second cylinder 4 enclose a second cavity 42 therebetween. A second elastic member 41 is provided in the second chamber 42, one end of the second elastic member 41 extends into the flange 24 to abut against the end face of the second end 22 of the first cylinder 2, and the other end extends out of the flange 24 to abut against the bottom end of the second cylinder 4. The second cylinder 4 is axially movable relative to the first cylinder 2 under the action of the chain 9 and compresses the second elastic member 41.

That is, as shown in fig. 1 and 2, the first cylinder 2 pushes the second cylinder 4 in the axial direction by the second elastic member 41 under the combined action of the first elastic member 23 and the hydraulic pressure in the first chamber 3. The second cylinder 4 can directly compress the chain 9, or the second cylinder 4 is in transmission connection with the tensioning rail 8, and the second cylinder 4 pushes the tensioning rail 8 along the axial direction, so that the chain 9 is compressed.

Referring to fig. 2 and 3, the tensioner 7 includes a first drain passage 31, a second drain passage 6, and an oil return passage 14, the first drain passage 31 and the second drain passage 6 serving to communicate the first chamber 3 with the outside. The oil drain passage is a passage that communicates the first chamber 3 with the outside so that the oil in the first chamber 3 can be discharged when the first chamber 3 is compressed or the hydraulic pressure in the first chamber 3 increases. The oil return channel 14 is used to communicate the first cavity 3 with the oil inlet 12 to form a bypass oil path corresponding to the check valve 13, and the oil return channel 14 also has the function of discharging the oil in the first cavity 3 when the first cavity 3 is compressed or the hydraulic pressure in the first cavity 3 increases, but not directly discharging the oil out of the tensioner 7, but returning to the oil inlet 12.

That is, the oil discharged from the first chamber 3 can be discharged to the oil pan through the oil drain passage or can be returned to the oil inlet 12 through the oil return passage 14 to achieve internal circulation.

Specifically, the oil return passage 14 always communicates the first chamber 3 with the oil inlet 12, and the first oil drain passage 31 always communicates the first chamber 3 with the outside. But the second oil drain channel 6 is provided with an on-position and an off-position. When the distance that the second cylinder 4 moves in the direction of compressing the second elastic member 41 is greater than or equal to the set threshold value, the second drain passage 6 is switched to the off-position. When the distance that the second cylinder 4 moves in the direction of compressing the second elastic member 41 is smaller than the set threshold value, the second drain passage 6 is switched to the communication station. Wherein the setting of the threshold value can be performed by a person skilled in the art based on the stiffness variation value of the tensioner and the dynamic performance of the chain system.

In the above embodiment, as shown in fig. 2 and 3, the first oil drain channel 31 may be generally formed by a gap between the outer wall of the first cylinder 2 and the inner wall of the housing 1, or a separate slot may be formed on the outer wall of the first cylinder 2 to achieve a stable throttling effect, so that no matter what structure is used, it should be ensured that one end of the first oil drain channel 31 is always communicated with the first cavity 3, and the other end of the first oil drain channel 31 is led to the outside of the tensioner 7. The oil return channel 14 is generally formed on the outer wall and the bottom surface of the check valve 13, and cooperates with the housing 1 to form a slot communicating the first chamber 3 with the oil inlet 12, the slot generally being in a labyrinth-like orientation to increase the throttling effect. Thus, the first oil drain passage 31 and the oil return passage 14 can each perform a basic oil drain function in the first chamber 3, except that the oil consumption of the tensioner 7 can be reduced by bypassing the oil drain through the oil return passage 14. The person skilled in the art can thus choose whether the first drain channel 31 and the return channel 14 need to be provided at the same time, as well as the throttle parameters thereof, depending on the value of the variation in the stiffness of the tensioner and the dynamic performance of the chain system.

During operation of the chain system of the engine, the tension rail 8 is caused to oscillate to a certain extent as a function of the dynamic tension of the chain 9, the tension of the chain 9 acting on the second elastic member 41 through the second cylinder 4. The second elastic member 41 transmits the force of the chain 5 to the first cylinder 2 at this time so that the first cylinder 2 forms a movement tendency in the same direction as the second cylinder 4.

But the second elastic member 41 is reacted by the first cylinder 2 due to the first cylinder 2 being subjected to the hydraulic pressure from the first chamber 3 and the common thrust of the first elastic member 23. At this time, the second elastic member 41 is compressed, and thus the second cylinder 4 is displaced in the axial direction with respect to the first cylinder 2 in the direction in which the second elastic member 41 is compressed. When the displacement meets the set threshold, the second cylinder 4 can close the second oil drain passage 6, and the oil can only be drained from the remaining oil return passage 14 and the first oil drain passage 31 in the normally-open state. The drain rate corresponding to the first chamber 3 is reduced. At this time, the damping of the tension of the chain 9 by the oil of the first chamber 3 is large, and the tensioner 7 operates in the high damping mode. Thus, even if the tension and variation of the chain 9 are large during high-speed and heavy-load operation of the engine, the tensioner 7 can effectively press the chain 9, and at this time, the tensioner 7 has high rigidity, so that the chain system can be kept stable.

When the engine works at medium and low speed, the chain 9 works stably, the tension is low and the change is small, and the swing amplitude of the tensioning rail 8 is small. Therefore, the displacement of the second cylinder 4 at this time is small, and the set threshold is not reached. The second oil drain passage 6 is in a communicating state, and the high-pressure oil in the first chamber 3 can be drained faster via the oil return passage 14, the first oil drain passage 31, and the second oil drain passage 6 at the same time. This effectively reduces the amount of damping of the tension of the chain 9 by the oil in the first chamber 3, and the tensioner 7 operates in a low damping mode. At this time, the tensioner 7 has small rigidity, namely the tensioner 7 is softer, and the dynamic tension of the chain 9 at this time can be obviously reduced, so that the friction loss of the chain system is reduced, the noise of the chain system is reduced, and the reliability of the chain system is improved.

The specific structure of the second drain passage 6 will be described below.

Example 1

In a specific embodiment, as shown in fig. 3, the second drain passage 6 includes a first segment 61. The first stage 61 serves to communicate the first chamber 3 with the outside. The first segment 61 penetrates through a portion of the first cylinder 2 surrounding the first chamber 3 in the thickness direction to form a first mouth portion 61a and a second mouth portion 61b at a chamber wall of the first chamber 3 and an outer peripheral wall of the first cylinder 2, respectively. The second port 61b communicates with the outside of the tensioner 7, and when the second cylinder 4 moves in the axial direction, the second port 61b can be blocked or the second port 61b can be opened to switch the second drain passage 6 between the off-position and the on-position.

The second end 22 of the first cylinder 2 forms a gap 11 between the housing 1 in the radial direction. The gap 11 communicates with the outside, and the second mouth 61b is located at a portion of the first cylinder 2 surrounding the gap 11. The second cylinder 4 is sleeved outside the second end 22 and the flange 24, and the second cylinder 4 moves axially in the gap 11 to open or close the second opening 61b.

Specifically, with continued reference to fig. 3, the first cylinder 2 is configured to have a stepped diameter in the axial direction, and the radial dimension of the first end 21 is greater than the radial dimension of the second end 22. The inner diameter of the housing 1 is adapted to the radial dimension of the first end 21 such that the radial dimension of the second end 22 is smaller than the inner diameter of the housing 1. Thereby, a gap 11 communicating the outside is formed between the outer wall of the second end 22 and the inner wall of the housing 1. The second cylinder 4 is movable in the gap 11 in the axial direction of the first cylinder 2.

In the present embodiment, the second cylinder 4 compresses the second elastic member 41 under the urging of the tension rail 8. The second elastic member 41 transmits the pushing force of the tension rail 8 applied to the second cylinder 4 to the first cylinder 2, and the first cylinder 2 in turn compresses the first chamber 3 and the first elastic member 23. The hydraulic pressure of the first chamber 3 and the elastic force of the first elastic member 23 act on the second elastic member 41 together to deform the second elastic member 41 a certain distance, and the second cylinder 4 moves a certain distance toward compressing the second elastic member 41.

If the swing of the tension rail 8 is small, as shown in the state of fig. 3 and 4, the second cylinder 4 moves in the direction of compressing the second elastic member 41, but the distance of movement is smaller than the set threshold value, and the second cylinder 4 does not cover the second mouth portion 61b. At this time, the second oil drain channel 6, the first oil drain channel 31 and the oil return channel 14 can drain the engine oil in the first cavity 3, and the oil drain speed of the first cavity 3 is higher. At this time, the rigidity of the tensioner 7 is soft.

If the swing of the tension rail 8 is large, as shown in fig. 5 and 6, when the distance traveled by the second cylinder 4 reaches a set threshold, the inner wall of the second cylinder 4 moves beyond the second opening 61b to cover and seal the second opening 61 b. At this time, the oil in the first chamber 3 cannot be discharged from the second oil discharge passage 6, and only the first oil discharge passage 31 and the oil return passage 14 are discharging oil. At this time, the drain rate in the first chamber 3 is lowered, and the rigidity of the tensioner 7 is stiff.

Optionally, as shown in fig. 3 to 6, the second drain passage 6 further includes a second section 63 that serves as a throttle. Specifically, a filling portion 5 is further provided in the first chamber 3. The filling part 5 serves to adjust the volume of the first chamber 3. The filling portion 5 is connected to the second end 22 of the first cylinder 2, and the side wall of the filling portion 5 and the inner wall of the second end 22 of the first cylinder 2 define a second segment 63. The second section 63 is a third oil groove 51 having a spiral or other labyrinth shape formed in the filling portion, and the inner wall of the first cylinder 2 covers the third oil groove 51, thereby enclosing a channel through which the oil supply liquid can flow.

One end of the second stage 63 communicates with the first chamber 3, and the other end communicates with the first port 61a of the first stage 61, so that the oil in the first chamber 3 can enter the first stage 61 from the second stage 63.

Example two

In the present embodiment, as shown in fig. 7 and 8, in the first embodiment, an annular second oil groove 64 corresponding to the second opening 61b is provided on the outer wall surface of the second end 22 of the first cylinder 2 of the tensioner 7, and a first oil groove 62 which always communicates with the second oil groove 64 and the second opening 61b is provided on the inner wall of the second cylinder 4 of the tensioner 7. The first segment 61 penetrates the wall of the first cylinder 2 in the thickness direction. One end of the first stage 61 communicates with the first chamber 3, and the other end can communicate with the first oil groove 62. The first oil groove 62 is provided in a portion of the second cylinder 4 overlapping the first cylinder 2.

The first oil sump 62 can be switched between an open position and a closed position to switch the second oil drain passage 6 between an on-position and an off-position when the second cylinder 4 is moved relative to the first cylinder 2.

Specifically, the outer wall of the first cylinder 2 encloses the first oil sump 62 when the second oil drain passage 6 is in the break-off position. Conversely, in the communication station, the first oil sump 62 communicates with the second chamber 42.

The first cylinder 2 comprises a first end 21 with an opening and a second closed end 22, and the second cylinder 4 is arranged around the second end 22 and encloses a second cavity 42 with the second end 22. The first chamber 3 is spaced from the second chamber 42, the first chamber 3 being separated from the second chamber 42 by an end face of the second end 22 of the first barrel 2.

The first segment 61, the second oil groove 64, and the first oil groove 62 communicate the first chamber 3 with the second chamber 42.

The second chamber 42 communicates with the outside through an oil outlet 43.

In the present embodiment, unlike the first embodiment, the engine oil does not enter the gap 11 from the second port 61b, but enters the second oil groove 64 and the first oil groove 62 through the second port 61 b.

Specifically, an annular groove corresponding to the second opening 61b is provided on the outer wall surface of the second end 22 of the first cylinder 2, and the inner wall of the second cylinder 4 covers the notch of the groove in the radial direction, thereby enclosing an annular oil passing channel, namely a second oil groove 64, and the second oil groove 64 plays a role in guiding so that the engine oil flowing out from the second opening 61b can reach any position on the circumference. A first oil groove 62 is formed in the inner wall of the second cylinder 4 in the axial direction. The first oil groove 62 is formed by being recessed outward from the inner wall of the second cylinder 4. In the radial direction, the outer wall of the first cylinder 2 covers the notch of the oil groove so as to enclose an oil passage, and the first oil groove 62 plays a guiding role so that the engine oil can flow in the extending direction of the oil groove.

Referring to fig. 7, when the first oil groove 62 is in the above-described open position, at least a portion of the first oil groove 62 located in the second chamber 42 is offset from the first cylinder 2 in the axial direction to form an oil drain port 62a. That is, when the second cylinder 4 moves slightly in the axial direction with respect to the first cylinder 2, a relatively small movement is also caused between the first oil groove 62 and the first cylinder 2 in the axial direction. At this time, the end of the first oil groove 62 in the extending direction is not yet covered by the outer wall of the first cylinder 2. The oil in the first chamber may be discharged into the second chamber 42 through the oil discharge port 62a via the first stage 61, the second oil groove 64, and the first oil groove 62. By allowing the engine oil to enter the second chamber 42, lubrication can be provided to the first cylinder 2. At the same time, the drain rate of the first chamber 3 is also increased by communicating the second drain passage 6 with the second chamber 42. At this time, the hardness of the tensioner 7 is low.

As shown in fig. 8, when the first oil groove 62 is in the closed position, the oil groove is entirely covered by the first cylinder 2 in the axial direction. At this time, the distance the second cylinder 4 moves under the action of the tension rail 8 is equal to or greater than the set threshold value. At this time, the first oil groove 62 is also axially moved relative to the first cylinder 2. The end of the first oil groove 62 extending (the position indicated by the arrow a in the drawing) is moved relative to the first cylinder 2 so that the end of the first oil groove 62 extending is also covered by the outer wall of the first cylinder 2. At this time, the first oil groove 62 is blocked. After the oil enters the first oil groove 62 through the second port 61b, the oil cannot be discharged, and the second drain passage 6 is in the off position. Further, the drain rate of the first chamber 3 is reduced, and the hardness of the tensioner 7 is increased.

Alternatively, the first oil groove 62 extends in a straight line in the axial direction. Of course, the first oil groove 62 may extend in a spiral shape. And can be selected by the person skilled in the art according to the need.

Optionally, in this embodiment, the second cylinder 4 is provided with an oil outlet 43, and the oil outlet 43 is used to drain the oil in the second cavity 42.

The second cylinder 4 abuts against the tensioning rail 8 to press the chain 9, and the oil outlet 43 is arranged at a position where the second cylinder 4 contacts with the tensioning rail 8. So that the oil in the second chamber 42 can be discharged through the oil outlet 43 to lubricate the place where the second cylinder 4 contacts the tension rail 8.

The principles and embodiments of the present application have been described herein with reference to specific examples, the description of which is intended only to facilitate an understanding of the method of the present application and its core ideas. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the application can be made without departing from the principles of the application and these modifications and adaptations are intended to be within the scope of the application as defined in the following claims.

Claims (10)

1. The hydraulic automatic tensioner is characterized by comprising a shell, a first cylinder body, a second cylinder body, a first oil drainage channel and a second oil drainage channel, wherein the shell is sleeved on the first cylinder body and surrounds a first cavity with the first cylinder body, and the first cavity is used for containing engine oil from an engine;

the second cylinder is used for compacting the chain, is sleeved on the first cylinder and can axially move relative to the first cylinder under the action of the chain;

The first oil drain channel and the second oil drain channel are used for communicating the first cavity with the outside, the first oil drain channel is always communicated with the outside, and the second oil drain channel is provided with a communicating station and a disconnecting station;

The second oil drainage channel comprises a first section part, wherein the first section part penetrates through the wall of the first cylinder body to form a first opening part in the first cavity, and a second opening part is formed in the outer peripheral wall of the first cylinder body;

when the second cylinder moves axially, the second opening can be blocked or opened, so that the second oil drain channel is switched between the connection station and the disconnection station.

2. The hydraulic automatic tensioner according to claim 1, wherein the first cylinder is provided with opposite first and second ends in an axial direction, and the second cylinder is sleeved on the second end.

3. The hydraulic automatic tensioner of claim 2, wherein an inner wall of the second cylinder engages the second mouth to block the second mouth or disengages the second mouth to open the second mouth.

4. The hydraulic automatic tensioner according to claim 2, wherein the first end is built in the housing, the second end forms a gap with the housing in a radial direction, the gap communicates with the outside, and the second mouth is located at a portion of the first cylinder surrounding the gap;

The second cylinder moves axially within the gap to open or close the second mouth.

5. The hydraulic automatic tensioner according to claim 4, wherein the first end is open and the second end is closed, the second cylinder and the second end enclosing a second chamber, the first chamber being spaced from the second chamber;

The inner wall of the second cylinder is provided with a first oil groove which is always communicated with the second opening, the first cylinder is also provided with a second oil groove, the second oil groove is arranged on one side where the second opening is located, and the first oil groove and the second oil groove are always communicated;

At the disconnection station, the outer wall of the first cylinder body seals the first oil groove;

At the communication station, the first oil groove is communicated with the second cavity.

6. The hydraulic automatic tensioner according to claim 5, wherein the second cylinder is provided with an oil outlet for discharging oil and air in the second chamber;

The second cylinder is used for propping against the tensioning rail to compress the chain, and the oil outlet is arranged at the position where the second cylinder contacts with the tensioning rail.

7. The hydraulic automatic tensioner according to any one of claims 1 to 6, wherein the housing is configured with an oil inlet, the tensioner further comprising a check valve provided to the oil inlet, a valve port of the check valve being in communication with the oil inlet;

The hydraulic automatic tensioner further comprises an oil return channel, and a groove is formed in the contact area between the outer part of the one-way valve and the shell, so that bypass connection is formed between the first cavity and the oil inlet to serve as the oil return channel.

8. The hydraulic automatic tensioner according to any one of claims 1 to 6, further comprising a filling portion provided in the first chamber, the filling portion being connected to an end of the first cylinder near the second cylinder;

The second oil drainage channel further comprises a second section part, the second section part is a third oil groove formed in the filling part, one end of the third oil groove is communicated with the first cavity, and the other end of the third oil groove is communicated with the first opening part.

9. The hydraulic automatic tensioner of claim 8, wherein the third oil groove extends in a spiral.

10. An engine system comprising a chain and the hydraulic automatic tensioner of any one of claims 1-9, the hydraulic automatic tensioner compressing the chain.