JP2005098383A - Hydraulic tensioner for valve system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic tensioner for a valve system that is less likely to have effects of ambient temperature to achieve stable actuation performance. <P>SOLUTION: In this hydraulic tensioner 11 for a valve system, a piston 28 is slidably provided in a body 26. A high pressure chamber 34 in which operation fluid is filled is parted from a reserve chamber 35. A free piston 38 is also provided to part the reserve chamber 35 from an air chamber 41. The air chamber 41 is opened to the external of the body 26. A free piston spring 42 to energize the free piston 38 is disposed in the air chamber. The free piston 38 is energized by the free piston spring 42 in such a direction as to enlarge the air chamber 41. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an improvement of a valve operating hydraulic tensioner used for adjusting tension of an engine cam chain, a timing belt, or the like.

  As this kind of conventional thing, there exists a thing as described in patent document 1 and patent document 2, for example. Patent Document 1 discloses a free piston type auto tensioner, and Patent Document 2 discloses a hydraulic tensioner having a diaphragm.

  In Patent Document 1, the paragraph number [0013] states that “FIG. 5 is a cross-sectional view of the auto tensioner 41 according to the second embodiment. The second embodiment is the same as the first embodiment described above. The case where the present invention is applied to a free piston type auto tensioner 41 of a type different from that of the auto tensioner 1 is shown. The body 42 and a plan that slides in the body 42 and constitutes the first oil chamber 47 together with the body 42 are shown. The jar 43 and the plunger 43 are formed integrally with the rod 43A that protrudes from the body 42 and abuts against an idler (not shown), and is slidable between the inner periphery of the body 42 and the outer periphery of the rod 43A via seals. The piston 46 is inserted and constitutes the second oil chamber 48 together with the plunger 43, and the piston 46 is pressed downward to pressurize the second oil chamber 48. An elastic member 51 and a check valve 52 that allows the hydraulic oil to flow from the second oil chamber 48 to the first oil chamber 47 and prohibits the hydraulic oil from flowing from the first oil chamber 47 to the second oil chamber 48. The plunger 43 is formed with an oil passage 49 that communicates the first oil chamber 47 and the second oil chamber 48.

  An air chamber is formed above the piston 46, and an elastic member 51 is disposed in the air chamber. When the pressure in the second oil chamber 48 increases and the piston 46 is about to rise, the elastic member 51 51 and the air chamber are compressed.

  On the other hand, in Patent Document 2, paragraph numbers [0007], [0008], and [0009] include: “The hydraulic tensioner 10 of the present invention is a hollow housing in which an intermediate partition wall 12 is formed as shown in FIG. 14, a cylindrical cylinder 16 is concentrically disposed, and a piston rod 18 slides within the cylinder 16 with a small interval between the cylinder 16 and the piston rod 18. A high pressure oil chamber 20 defined by the cylinder 16 and the piston rod 18 is provided with a check valve 22. It is in communication with the outside via the valve and resists the pushing force acting on the piston rod 18.

  The piston rod 18 protrudes from one end opening of the housing 14, and a seal 24 surrounds the piston rod 18 and seals the housing opening. The seal 24 defines a low-pressure oil chamber 26 that fills the housing 14 with hydraulic oil. A rod guide 28 is fixed to the piston rod 18 in the low pressure oil chamber 26 of the housing 14. The gap between the housing 14 and the rod guide 28 is small in order to limit the flow of hydraulic oil. Therefore, when the piston rod 18 protrudes, the oil pressure in the low-pressure oil chamber 26 on the seal side is maintained at a positive pressure by the rod guide 28.

  A rear opening is covered with a diaphragm 30 by the intermediate partition wall 12, and a hydraulic oil reservoir 32 is formed. The low pressure oil chamber 26 communicates with the hydraulic oil reservoir 32 through the oil passage 34, and the hydraulic oil flowing out from the small gap between the cylinder 16 and the piston rod 18 flows into the hydraulic oil reservoir 32 through the oil passage 34.

  A spring 36 is interposed between the housing 14 and the rod guide 28 so as to apply a projecting output to the piston rod 18. Accordingly, when the belt tension is relaxed, the piston rod 18 protrudes, and the hydraulic oil in the hydraulic oil reservoir 32 quickly flows into the high-pressure oil chamber 20 via the check valve 22 to recover the belt tension. Conversely, when the belt tension becomes excessive, the hydraulic oil in the high pressure oil chamber 20 resists the pushing force in the backward direction of the piston rod, and the hydraulic oil slowly flows out from the small gap between the cylinder 16 and the piston rod 18. Gradually reduce the belt tension. Is disclosed.

A sealed air chamber is formed on the left side of the diaphragm 30 in the figure, and when the pressure in the hydraulic oil reservoir 32 increases, the diaphragm 30 is elastically deformed toward the left side in the figure to compress the air chamber. The Rukoto.
Japanese Patent Laid-Open No. 2002-156014. JP-A-8-303538.

  However, in such a conventional one, in both of Patent Documents 1 and 2, since the air chamber is hermetically sealed, it is easily affected by the ambient temperature, and when it becomes hot, the air spring Therefore, unlike the case where the temperature of the piston 46 or the diaphragm 30 is low, the tensioner operating performance may change.

  Accordingly, an object of the present invention is to provide a valve operating hydraulic tensioner that is less susceptible to the influence of ambient temperature and can obtain stable operating performance.

  In order to solve this problem, the invention according to claim 1 is provided such that a piston is slidably provided in a body, and the high pressure chamber filled with hydraulic oil and the reserve chamber are partitioned by the piston, and the reserve is provided. A partition member for partitioning the chamber and the air chamber, the air chamber being opened to the outside of the body, and a biasing member for biasing the partition member disposed in the air chamber; Thus, a valve-operated hydraulic tensioner that urges the partition member in the direction of expanding the air chamber is provided.

  The invention according to claim 2 is characterized in that, in addition to the structure according to claim 1, the air chamber is open in the engine.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the partition member is a free piston through which a rod connected to the piston is slidably inserted, and the biasing member Is a metal spring.

  According to a fourth aspect of the present invention, in addition to the configuration of the first or second aspect, the partition member is a diaphragm, and the biasing member is a metal spring.

  The invention according to claim 5 is characterized in that, in addition to the configuration according to any one of claims 1 to 4, the part is arranged so as to face part of the engine when attached to the engine. And

  According to a sixth aspect of the present invention, in addition to the configuration according to any one of the first to fifth aspects, an air vent hole that connects the reserve chamber and the outside is formed, and the air vent hole is opened and closed. The air vent bolt is detachably screwed.

  The invention described in claim 7 is characterized in that, in addition to the structure described in any one of claims 4 to 6, it is provided for adjusting the tension of the cam chain of the engine.

  According to the first aspect of the present invention, the partition member that partitions the reserve chamber and the air chamber is provided, the air chamber is opened to the outside of the body, and further, the bias that biases the partition member into the air chamber is provided. Since the member is disposed and the biasing member is biased in the direction of expanding the air chamber by the biasing member, the air chamber is not hermetically sealed and opened to the outside even when the surroundings of the air chamber become high temperature. Accordingly, the spring force is obtained by the urging force of a separately provided urging member without the air spring acting, and therefore the piston movement is substantially the same when the temperature is high and low. Therefore, the tensioner operating performance can be stabilized.

  According to the second aspect of the present invention, since the air chamber is open inside the engine, it is possible to suppress the intrusion of dust into the air chamber as compared with the case where the air chamber is opened outside the engine.

  According to the third aspect of the present invention, the above-described effect can be obtained for the partition member that is a free piston.

  According to the invention described in claim 4, the above-described effect can be obtained for the partition member that is a diaphragm.

  According to the fifth aspect of the present invention, in a state where the valve operating hydraulic tensioner is attached to the engine and is disposed so that a part thereof faces the engine, the air chamber of the tensioner becomes high temperature. Because it is easy, it is more effective.

  According to the invention described in claim 6, since the air vent hole communicating with the reserve chamber is formed and the air vent bolt for opening and closing the air vent hole is detachably screwed, Since air can be vented through the air vent hole, assembly in oil is unnecessary, and assembly workability can be improved.

  According to the seventh aspect of the present invention, the cam chain is provided in the engine, and in the case where the valve operating system hydraulic tensioner is provided for adjusting the tension of the cam chain, the air chamber of the tensioner tends to become high temperature. Therefore, it is more effective.

Embodiments of the present invention will be described below.
Embodiment 1 of the Invention

  1 and 2 show a first embodiment of the present invention.

  First, the configuration will be described. Reference numeral 11 in FIG. 1 is a valve operating hydraulic tensioner, and this valve operating hydraulic tensioner 11 is arranged for adjusting the tension of the cam chain 13 of the engine 12.

  Specifically, the cam chain 13 is disposed in the engine 12 and is spanned over the crankshaft sprocket 16, the exhaust side camshaft sprocket 17, and the intake side camshaft sprocket 18. Is transmitted to both camshaft sprockets 17 and 18.

  A fixed-side pressing member 21 that presses one side of the cam chain 13 and a movable-side pressing member 22 that presses the other side are provided, whereby the cam chain 13 is configured not to vibrate while maintaining a predetermined tension. Has been.

  The movable-side pressing member 22 is formed in a curved shape, and is rotatably disposed by a rotation shaft 25 provided on the lower end side. The pressed portion 22a on the upper end side of the movable-side pressing member 22 The valve operating hydraulic tensioner 11 is in contact with the valve operating hydraulic tensioner 11 so that the vibration of the cam chain 13 is suppressed.

  Specifically, the valve operating hydraulic tensioner 11 has a cylindrical body 26 whose right end in the figure is closed, and in this body 26 is a cylindrical shape whose right end in the figure is closed. And a piston 28 is slidably disposed in the cylinder 27 so as to be slidable in the left-right direction.

  In the body 26, a mounting flange portion 26a is formed at a substantially central portion in the left-right direction, and a mounting hole 26b through which a bolt 29 is inserted is formed in the mounting flange portion 26a. As shown in FIG. It can be attached. The body 26 is formed with an air vent hole 26d in a closed wall 26c at the right end in the figure, and an air vent bolt 30 for opening and closing the hole 26d is detachably screwed into the air vent hole 26d. In addition, an air vent groove 26 e communicating with the air vent hole 26 d is formed in the inner wall of the body 26.

  The piston 28 is attached to the right end of the rod 31, a high pressure chamber 34 filled with hydraulic oil is provided on the right side of the piston 28, and a reserve chamber 35 is provided on the left side. In other words, the high pressure chamber 34 and the reserve chamber 35 are partitioned by the piston 28, and the air vent groove 26 e communicates with the reserve chamber 35.

  Further, when the pressure on the high pressure chamber 34 side becomes a predetermined value or more, the hydraulic oil in the high pressure chamber 34 is gradually returned into the reserve chamber 35 through the gap between the outer peripheral wall of the piston 28 and the inner wall of the cylinder 27. ing. Since the gap is very small, it does not appear on the drawing.

  Further, a hydraulic oil passage 28a is formed in the piston 28, and a check valve 36 for opening and closing the hydraulic oil passage 28a is provided.

  The check valve 36 includes a check ball 36 a that opens and closes the hydraulic oil passage 28 a and a pressing member 36 b that presses the check ball 36 a in a closing direction. The pressing member 36 b is provided in the high-pressure chamber 34. By being biased by the spring 37, the check ball 36a is biased in the direction of closing the hydraulic oil passage 28a via the pressing member 36b.

  The reserve chamber 35 is formed between the piston 28 and a free piston 38 as a “partition member”, and the free piston 38 is slidable in the left-right direction with respect to the rod 31.

  The free piston 38 has a substantially ring shape, and a seal 38a that slides on the rod 31 is provided on the inner peripheral edge, and an O-ring 38 that slides on the inner peripheral surface of the body 26 is provided on the outer peripheral edge. It has been.

  Further, an air chamber 41 is provided between the free piston 38 and a lid member 40 that is fixedly disposed on the left side of the piston 38 in the figure, and the communication hole 40a provided in the lid member 40 allows air to The chamber 41 is open to the outside, here the engine 12. The reserve chamber 35 and the air chamber 41 are partitioned by the free piston 38.

  In the air chamber 41, a free piston spring 42 as an “urging member” is provided between the lid member 40 and the free piston 38, and the free piston spring 42 causes the free piston 38 to be stored in the reserve chamber 35. The air chamber 41 is biased in the direction of expanding the air chamber 41.

  Further, a pressing cap 31 a is provided at the left end portion of the rod 31 in the drawing, and the pressing cap 31 a is in contact with the pressed portion 22 a of the movable side pressing member 22.

  Next, the operation will be described.

  When a large tension is suddenly applied to the cam chain 13 due to fluctuations in the rotation of the engine 12, the rod 31 of the valve operating hydraulic tensioner 11 receives the load without sliding suddenly. Will be suppressed.

  Further, when a large tension acts on the cam chain 13 for a predetermined time or longer, the rod 31 of the valve operating hydraulic tensioner 11 is gradually slid rightward in the drawing, so that the tension is relaxed.

  Further, when the cam chain 13 is extended and bent, the rod 31 slides to the left and the tension of the cam chain 13 can be adjusted.

  Specifically, when a load acts on the right side in the figure from the valve operating hydraulic tensioner 11 due to the tension of the cam chain 13, the piston 28 is pressed in the direction in which the high pressure chamber 34 is compressed (right direction in the figure). In this case, since the hydraulic oil passage 28a of the piston 28 is closed by the check valve 36, the hydraulic oil does not escape from the high pressure chamber 34 side to the reserve chamber 35 side via the hydraulic oil passage 28a. The rod 31 does not slide rapidly to the right in the figure. Therefore, even when a large load suddenly acts on the cam chain 13, vibration of the cam chain 13 can be suppressed.

  Further, when a large tension is applied to the cam chain 13 for a predetermined time or more and the high pressure chamber 34 side becomes high pressure, the hydraulic oil on the high pressure chamber 34 side is little by little through the gap between the outer peripheral wall of the piston 28 and the inner wall of the cylinder 27. Since the rod 31 is gradually slid to the right side in the figure because it goes out to the reserve chamber 35 side, the tension of the cam chain 13 is relieved. When hydraulic oil flows into the reserve chamber 35 side, the pressure on the reserve chamber 35 side increases and the free piston 38 slides to the left in the figure against the urging force of the free piston spring 42. The volume on the reserve chamber 35 side is increased.

  When the cam chain 13 is further bent, the piston 28 is slid to the left in the figure by the urging force of the valve spring 37, and the free piston 38 is slid to the right in the figure by the urging force of the free piston spring 42. Be made. As a result, the hydraulic oil in the reserve chamber 35 acts on the check valve 36 via the hydraulic oil passage 28a to open the valve 36, and the hydraulic oil flows into the high-pressure chamber 34 side. Thereby, it is possible to follow the slack of the cam chain 13 and the tension is adjusted.

  According to this, a free piston 38 that partitions the reserve chamber 35 and the air chamber 41 is provided, the air chamber 41 is opened to the outside of the body 26, and further, a free piston that biases the free piston 38 into the air chamber 41. Since the piston spring 42 is disposed and the free piston spring 42 urges the free piston spring 42 in a direction to expand the air chamber 41, the air chamber 41 is sealed even when the surroundings of the air chamber 41 become hot. Since the spring force is obtained by the biasing force of the separately provided free piston spring 42 without opening the air spring by opening to the outside instead of the equation, the temperature of the movement of the piston 28 is high. The tensioner operating performance can be stabilized because the time is substantially the same at low times.

Further, by separating the air chamber 41 and the reserve chamber 35 by the free piston 38, the valve operating system hydraulic tensioner 11 can be disposed sideways,
It can also be equipped for things that tilt or fall like a motorcycle.

  Furthermore, since the air chamber 41 is open in the engine 12, it is possible to suppress the intrusion of dust into the air chamber 41 as compared with the air chamber 41 open to the outside of the engine 12.

  Furthermore, in a state where the valve operating hydraulic tensioner 11 is attached to the engine 12 and a part thereof is disposed so as to face the engine 12, the air chamber 41 of the tensioner 12 is likely to become high temperature. It is effective.

  In addition, since the air vent hole 26d communicating with the reserve chamber 35 is formed and the air vent bolt 30 for opening and closing the air vent hole 26d is detachably screwed, the air vent hole 26d is formed during the assembly operation of the tensioner 11. Since the air can be vented, assembly in oil is unnecessary, and assembly workability can be improved. Moreover, since the arrow direction in FIG. 1 is the vertical direction in the vehicle-mounted state of the engine 12, the air bleeding bolt 30 is at a high position in this vehicle-mounted state, so that the hydraulic oil spills even if the air bleeding bolt 30 is removed. This makes it possible to replenish hydraulic fluid. Further, by causing the air vent hole 26d to communicate with the low-pressure reserve chamber 35 from the high-pressure chamber 34, it is possible to prevent the occurrence of a sealing problem.

Further, the cam chain 13 is provided in the engine 12, and in the case where the valve operating hydraulic tensioner 11 is provided for adjusting the tension of the cam chain 13, the air chamber 41 of the tensioner 11 is likely to become high temperature. Is.
[Embodiment 2 of the Invention]

  FIG. 3 shows a second embodiment of the present invention.

  The second embodiment is different from the first embodiment in that a diaphragm 45 and the like are provided.

  That is, the diaphragm 45 is disposed outside the cylinder 27, a second reserve chamber 46 is formed between the diaphragm 45 and the cylinder 27, and a space between the second reserve chamber 46 and the first reserve chamber 47 is formed. The hydraulic fluid communication path 48 communicates.

  An air vent hole 26f communicating with the hydraulic oil communication passage 48 is formed in the mounting flange portion 26a, and the air vent bolt 30 is detachably screwed into the air vent hole 26f.

  Further, an air chamber 41 is formed on the right side (outside) of the diaphragm 45 in the drawing, and the air chamber 41 is opened into the engine 12 through the air communication passage 49. A diaphragm spring 50 as an “urging member” is disposed, and the diaphragm 45 is urged to the left side in the drawing by the diaphragm spring 50.

  In such a case, when the tension of the cam chain 13 suddenly increases, the vibration of the cam chain 45 can be suppressed without causing the rod 31 similar to the first embodiment to slide greatly.

  Further, when a large tension acts on the cam chain 13 for a predetermined time or longer, the rod 31 of the valve operating hydraulic tensioner 11 is gradually slid rightward in the drawing, so that the tension is relaxed. That is, when the high pressure chamber 34 is pressurized by being pushed by the rod 31, the hydraulic oil on the high pressure chamber 34 side is gradually transferred to the first reserve chamber 47 side through the gap between the outer peripheral wall of the piston 28 and the inner wall of the cylinder 27. At the same time, it escapes to the second reserve chamber 46 side through the hydraulic fluid communication passage 48. As a result, the rod 31 gradually slides to the right in the drawing, so that the tension of the cam chain 13 is relieved. When hydraulic oil flows into the second reserve chamber 46 side, the pressure on the second reserve chamber 46 side increases, and the diaphragm 45 elastically deforms in the right direction in the figure against the urging force of the diaphragm spring 50. In addition, the volume of the second reserve chamber 46 is increased. On the contrary, the air in the air chamber 41 escapes to the engine 12 side through the air communication passage 49, and the volume of the air chamber 41 is reduced.

  Further, when the cam chain 13 extends and bends, the piston 28 is slid to the left in the drawing by the biasing force of the valve spring 37, and the diaphragm 45 is moved to the left in the drawing by the biasing force of the diaphragm spring 50. Is elastically deformed. As a result, the hydraulic oil in the first reserve chamber 47 acts on the check valve 36 via the hydraulic oil passage 28a to open the valve 36, and the hydraulic oil flows into the high pressure chamber 34 side. Thereby, since the rod 31 is slid leftward in the figure, it is possible to follow the slack of the cam chain 13.

Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.
Embodiment 3 of the Invention

  FIG. 4 shows a third embodiment of the present invention.

  In the second embodiment, the air chamber 41 formed by the diaphragm 45 or the like is communicated with the engine 12 through the air communication passage 49. In the third embodiment, the air chamber 41 is communicated through the communication hole 51. 41 communicates with the outside of the engine 12.

  In this way, the communication hole 51 can be formed more easily than the formation of the air communication passage 49 of the second embodiment.

  Since other configurations and operations are the same as those of the second embodiment, description thereof is omitted.

  In each of the above-described embodiments, the valve operating hydraulic tensioner 11 is applied to the cam chain 13. However, the present invention is not limited to this, and can of course be applied to a timing belt of the engine 12.

It is sectional drawing which shows the arrangement | positioning state of the valve operating system hydraulic tensioner which concerns on Embodiment 1 of this invention. FIG. 3 is a cross-sectional view of the valve operating hydraulic tensioner according to the first embodiment. It is sectional drawing which shows the arrangement | positioning state of the valve operating system hydraulic tensioner which concerns on Embodiment 2 of this invention. It is sectional drawing of the valve operating system hydraulic tensioner which concerns on Embodiment 3 of this invention.

Explanation of symbols

11 Valve system hydraulic tensioner
12 engine
13 Cam chain
26 body
26a Mounting flange
26d Air vent hole
26e Air vent groove
27 cylinders
28 piston
28a Hydraulic oil passage
30 Air vent bolt
31 Rod
34 High pressure chamber
35 Reserve room
36 Check valve
37 Valve spring
38 Free piston (partition member)
41 Air chamber
42 Free piston spring (biasing member)
45 Diaphragm (partition member)
46 Second reserve room
47 1st reserve room
48 Hydraulic oil communication passage
49 Air communication passage
50 Diaphragm spring (biasing member)
51 Communication hole

Claims (7)

A piston is slidably provided in the body, the high pressure chamber filled with hydraulic oil and the reserve chamber are partitioned by the piston, and a partition member is provided to partition the reserve chamber and the air chamber. Is opened to the outside of the body, and further, an urging member for urging the partition member is disposed in the air chamber, and the urging member urges the partition member in a direction to expand the air chamber. This is a valve operating hydraulic tensioner. The valve operating hydraulic tensioner according to claim 1, wherein the air chamber is open in the engine. 3. The partition member according to claim 1, wherein the partition member is a free piston through which a rod connected to the piston is slidably inserted, and the biasing member is a metal spring. Valve system hydraulic tensioner. The valve operating hydraulic tensioner according to claim 1 or 2, wherein the partition member is a diaphragm, and the urging member is a metal spring. The valve operating hydraulic tensioner according to any one of claims 1 to 4, wherein a part of the valve operating hydraulic tensioner is disposed so as to face a part of the engine when attached to the engine. 6. An air vent hole for communicating the reserve chamber and the outside is formed, and an air vent bolt for opening and closing the air vent hole is detachably screwed. The valve operating hydraulic tensioner described. The valve operating hydraulic tensioner according to any one of claims 4 to 6, which is provided for adjusting the tension of an engine cam chain.

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