WO2011036720A1

WO2011036720A1 - Valve timing regulator

Info

Publication number: WO2011036720A1
Application number: PCT/JP2009/004859
Authority: WO
Inventors: 長谷浩文
Original assignee: 三菱電機株式会社
Priority date: 2009-09-25
Filing date: 2009-09-25
Publication date: 2011-03-31
Also published as: DE112009005364B4; CN102472125A; US20120167846A1; JPWO2011036720A1; JP5335094B2; CN102472125B; DE112009005364T5

Abstract

A valve timing regulator is equipped with a recess which is provided to face the peripheral wall surface of the shoe and vane of an advance oil pressure chamber, a holding member which is inserted into the recess from the axial direction and arranged in place, and an assist spring arranged between the holding member on the shoe side and the holding member on the vane side in order to urge the rotor in the advancing direction, wherein the clearance formed by the axial length of the holding member provided on the vane side and the axial length of the case is set equal to or larger than the sum of an increment in the axial length in which the inclination of the holding member caused by the gap between the holding member and the recess is taken into account and an increment caused by thermal expansion. Since a state in which the holding member is stretched between the covers at the opposite ends is brought about by thermal expansion during oil temperature rise, inclination of the holding member when the holding member and the assist spring are attached, or inclination caused by operation or vibration of the rotor, malfunction such as increase in leakage due to drop in operating speed of the rotor caused by friction or abrasion of the sliding surface of a cover can be prevented.

Description

Valve timing adjustment device

The present invention relates to a valve timing adjusting device that automatically changes the opening / closing timing of an exhaust valve in accordance with the operating condition of an internal combustion engine.

This type of valve timing adjusting device includes a camshaft that opens and closes an exhaust valve of an internal combustion engine, a case that is rotatably provided on the camshaft and is rotationally driven by the output of the internal combustion engine, The rotor, which is housed in a relatively rotatable manner and connected to the camshaft, operates from a mechanical biasing force to restrain the relative rotation between the case and the rotor, and from the internal hydraulic chamber in a direction against the mechanical biasing force. And a lock means for releasing the restraint by operating with the fluid control pressure.

For the purpose of applying the valve timing adjusting device having such a configuration to the exhaust side, there has been proposed one in which an assist spring is arranged as means for urging the rotor in the advance direction in the internal hydraulic chamber. As a configuration for holding the assist spring, for example, Patent Document 1 discloses a configuration in which a resin holding member is inserted into a recess provided in a rotor and a case.

Japanese Patent No. 3964207

As described above, Patent Document 1 describes setting a pair of holding members that hold both ends of the assist spring, but details of the axial length and the shape of the assist spring insertion hole entrance are described. However, in actual use, the holding member is inclined between the cover and the housing due to thermal expansion or the like because the holding member is tilted within the gap between the recess and the housing, and the rotor operating speed decreases due to friction or the cover and housing There is a problem that there is a concern about problems such as increased leakage due to wear of the sliding surface.

The present invention has been made to solve the above-mentioned problems caused by a holding member that holds an assist spring installed in a hydraulic chamber, and is a valve timing adjustment that solves a decrease in operating speed and a decrease in durability. An object is to provide an apparatus.

The valve timing adjusting device according to the present invention includes a plurality of shoes formed on the inner peripheral surface of the case, and an outer peripheral surface of a rotor housed in the case so as to be relatively rotatable, between both side walls in the circumferential direction of each shoe. A plurality of vanes forming the retard hydraulic chamber and the advance hydraulic chamber, a recess provided facing the circumferential wall surface of the shoe and the vane of the advance hydraulic chamber, and an axially inserted into the recess. A holding member; and an assist spring disposed between the shoe-side holding member and the vane-side holding member and biasing the rotor in the advance direction, and the axial length of the holding member provided on the vane side And the clearance formed from the axial length of the case to be equal to or greater than the sum of the axial length increase taking into account the inclination of the holding member caused by the gap between the holding member and the recess and the increase due to thermal expansion. It is set.

According to the present invention, in order to improve the assembly of the assist spring, the clearance formed from the axial length of the holding member provided on the vane side and the axial length of the case is reduced from the gap between the holding member and the recess. The holding member is set to be equal to or greater than the sum of the axial length increase considering the tilt of the holding member and the increase due to thermal expansion, so the holding member is within the range of the gap provided between the vane and the recess of the shoe. Or thermal expansion when the oil temperature rises (the rotor and the case are ferrous materials and have a smaller linear expansion coefficient than the resin holding member), the inclination of the holding member when the holding member and the assist spring are assembled, and the rotor operation Even if tilt is caused by vibration or vibration, it may be stretched between the cover and the housing at both ends, or the rotor operating speed may be reduced due to friction or the cover sliding surface may be worn out. Increase problems such as can be reliably prevented.

FIG. 3 is a radial cross-sectional view of the valve timing adjusting device according to the first embodiment of the present invention taken along line 2-2 in FIG. 1 is a sectional view in the axial direction of a valve timing adjusting device according to Embodiment 1 of the present invention, taken along line 1-1 in FIG. It is a front view which shows the state which assembled | attached the assist spring in the assist spring insertion hole of the holding member inserted in the recessed part of the vane. FIG. 4 is a longitudinal side view taken along line 3-3 in FIG. 3.

Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
FIG. 1 is a sectional view of a valve timing adjusting device according to Embodiment 1 of the present invention in the radial direction along line 2-2 in FIG. 2, and FIG. 1 is a cross-sectional view in the axial direction along line 1-1 of FIG.

In the figure, the case 1 has a sprocket portion 2 that transmits a driving force from a crank (not shown) on the outer periphery, and has shoes 3a to 3d that form hydraulic chambers on the inner periphery. The rotor 4 divides the four hydraulic chambers formed by the shoes 3a to 3d of the case 1 into the advance-side hydraulic chambers 5a to 5d and the retard-side hydraulic chambers 6a to 6d, and also serves as a pressure receiving portion for the oil pressure. 7d is arranged outside at almost 90 ° intervals. The rotor 4 has a boss portion 9 having a predetermined clearance and is in sliding contact with the inner sliding portion 8 of the case 1 and has an oil seal and a bearing function.

Further, a recess is formed at the tip of the vanes 7a to 7d, and a seal member 10 for restricting the oil flow between the hydraulic chambers is disposed. The rotor 4 is inserted into a camshaft (not shown) inside the boss portion 9 and fastened and fixed with a bolt (not shown). As shown in FIG. 2, the case 1 and the rotor 4 are sealed at both end faces by a cover 11 and a housing 12, and are fastened by four bolts 13.

Hereinafter, the oil passage formed in the rotor 4 will be described. The boss portion 9 of the rotor 4 has an advance angle side passages 17a to 17d and a retard angle side passages 18a to 18d communicating with an oil passage (not shown) formed in the camshaft and penetrating in the radial direction. The hydraulic fluid is supplied to the hydraulic chamber in communication with the angular hydraulic chambers 5a to 5d and the retarded hydraulic chambers 6a to 6d.

The shoe 3b of the case 1 is formed with a hole 21 penetrating in the radial direction, and is fitted into a fitting hole 22 formed in the boss portion 9 of the rotor 4 so that the rotor 4 is a reference position at the time of starting. A lock pin 23 that is regulated at the most advanced position is accommodated so as to be movable in the axial direction. The lock pin 23 is urged in a fitting direction by a spring 24, and the spring 24 is held by a stopper 25. Further, the lock pin 23 receives a retard side oil pressure by a retard side oil passage 26 opened at the bottom of the fitting hole 22 and receives the pressure at the tip part, thereby retreating radially outward against the spring 24. And the restriction | limiting of the rotor 4 can be cancelled | released.

Next, the assist spring 27 that urges the rotor 4 in the advance direction will be described. The vanes 7a (up to 7d) of the rotor 4 and the shoes 3a (up to 3d) of the case 1 are respectively formed with

recesses

28 and 29 penetrating in the axial direction.

Members

30 and 31 are inserted. The assist spring 27 is inserted into assist

spring insertion holes

32 and 33 formed on the side surfaces of the

holding members

30 and 31.

Thus, the assist spring 27 is arranged in the advance side hydraulic chamber. In the illustrated example, a total of eight are arranged in each hydraulic chamber. At the most advanced angle position where the set length of the assist spring 27 is the longest, the assembly of the pair of holding members and the assist spring 27 is considered so that the assembly can be easily inserted by a machine, and the holding member with respect to the set length. For the purpose of preventing the assist spring 27 from being displaced in the radial direction and deforming, the support length is set to be straight. That is, in FIG. 1, the bottom surface P of the holding member 30 and the bottom surface Q of the holding member 31 are arranged so as to be parallel to each other.

At the most retarded angle position where the set length of the assist spring 27 is the shortest, the assist spring 27 is arranged in an arc shape that warps against the inside of the apparatus. Further, a taper 35 for narrowing the opening is formed at the opening edge of the recess 28 provided in the rotor-side vane 7a (up to 7d) for rotating operation, and both sides of the holding member 30 are shown in FIG. As shown, a taper 34 that contacts the taper portion 35 is formed. By doing so, it is possible to prevent the holding member 30 from being accidentally removed from the recess 28 even during the rotor operation.

The installation purpose of the

holding members

30 and 31 is to facilitate assembly when the plurality of assist springs 27 are installed in a deformed space such as a hydraulic chamber. Therefore, a predetermined gap is set between the

holding members

30 and 31 and the

recesses

28 and 29 so that the holding member can be easily inserted. Due to the gap, the

holding members

30 and 31 are configured to have rattling in the

recesses

28 and 29, and the

holding members

30 and 31 are inclined in the vertical and horizontal directions by the gap.

Here, the

holding members

30 and 31 are molded of resin, and the linear expansion coefficient thereof is from the case 1 (in this Embodiment 1, made of iron-based sintered metal) that forms a space into which the holding member is inserted. Therefore, the size in the apparatus axial direction of the

holding members

30 and 31 is set smaller than that of the case 1 by a difference of the linear expansion coefficient: ΔT so as not to be stretched in the case 1 at the time of thermal expansion.

However, when the inclination of the holding member 30 described above occurs, as shown in FIG. 3, the dimensions of the

holding members

30 and 31 in the apparatus axial direction are apparently larger than those in the vertical case. 30 and 31 are stretched in the case 1. If this state occurs on the rotor side, the operating speed decreases and the cover 11 and the housing 12 wear due to the increased frictional force.

That is, in order to suppress the bearing surface wear of the assist spring 27, when the holding member 30 is made of, for example, glass or the like as an additive, the wear of the counterpart material becomes significant. Here, in the first embodiment, the clearance between the

holding members

30 and 31 and the cover 11 and the housing 12 is also set in consideration of the dimensional increase in the apparatus axial direction due to the inclination of the holding member 30: ΔC. ΔT + ΔC) or more. The holding member 30 has a maximum thermal expansion ΔT of 40 μm and a maximum inclination ΔC of 90 μm. By doing so, it is possible to obtain stable device operability and durability without the holding

members

30 and 31 being stretched in the case 1 even by rattling.

Further, as shown in FIG. 4, at the entrances of the assist spring insertion holes 32, 33 of the holding

members

30, 31, the width: Lh is larger than the line distance: Ls of the assist spring 27 at the most advanced position (Lh). > Ls) is formed. By setting in this way, as the rotor 4 moves from the most advanced position to the retard direction, the assist spring 27 gradually compresses while being deformed into an arc shape (the distance between the assist spring lines is reduced). ), The assist spring 27 can be stably held without the assist spring wire being caught by the entrance edge of the holding member 30.

Next, the operation of the device will be described. First, when the valve timing adjusting device is controlled to the most advanced angle position, which is the reference position, such as when the engine is started or idling, the oil control valve (not shown) is not energized and passes through an engine advance angle side passage (not shown). Hydraulic pressure is supplied to the advance side hydraulic chamber 5, and the rotor 4 is fixed at the most advanced position. At this time, the bottom surfaces P and Q of the holding

members

30 and 31 are parallel, and the assist spring 27 is straight as shown in FIG. Further, the lock pin 23 is fitted in the fitting hole 22.

Next, when a command for retarding operation is issued to the valve timing adjusting device due to an increase in the rotational speed or the like, a predetermined current is applied to the oil control valve, an output port on the retarding side is opened, and an engine delay (not shown) is performed. First, oil is supplied to the retarded-side oil passage 26 of the valve timing adjusting device through the corner-side passage, and the pressure is received by the tip of the lock pin 23, so that the lock pin 23 resists the urging force of the spring 24 and is out of the diameter. It moves to a direction, comes out of the fitting hole 22, and cancels | regulates the rotor 4. FIG.

Here, when the lock pin 23 is fitted, the retard side passages 18a to 18d are closed by the shoe portion of the case 1, and no hydraulic pressure is supplied to the retard side hydraulic chamber 6. When the lock pin 23 is released, the rotor 4 is shaken by the cam alternating torque, so that the blocked retarding passage is opened and oil is supplied to the retarding hydraulic chamber.

When the oil is supplied to the retarding side hydraulic chamber, a rotational torque in the retarding direction is generated in the rotor 4 and starts operating against the assist spring torque in the advancing direction together with the cam torque in the retarding direction. At this time, the holding

members

30 and 31 are inclined due to vibrations of the engine within the range of the

recesses

28 and 29, and the engine oil that is the working fluid of the valve timing adjusting device is about 100 ° C. along with the engine rotation. Even when the holding

members

30 and 31 are thermally expanded by being heated, the rotor 4 can operate normally without the holding

members

30 and 31 being stretched in the case 1.

As described above, according to the first embodiment, since the purpose of installing the holding member is to improve the assembly of the assist spring, a predetermined gap is provided between the holding member and the recess of the vane or shoe. The holding member is tilted within the gap. However, by doing so, the thermal expansion when the oil temperature rises (the rotor and the case are iron-based materials, and the linear expansion coefficient is smaller than that of the resin holding member), and the holding member and the assist spring are assembled when the assist spring is assembled. The holding member is stretched between the cover and the housing at both ends due to tilt, rotor operation, vibration, etc., causing problems such as a decrease in rotor operating speed due to friction and increased leakage due to wear of the cover sliding surface However, the clearance formed by the axial length of the holding member provided on the vane side and the axial length of the case is determined in consideration of the inclination of the holding member caused by the gap between the holding member and the recess. Since it is set to be equal to or greater than the sum of the increase in length and the increase due to thermal expansion, the above-described problems can be reliably prevented.

In addition, since the holding member installed on the rotor side is provided with a means for preventing the holding member from being detached, thereby preventing the holding member from tilting, for example, the holding member does not follow when the rotor advances rapidly at high hydraulic pressure. It is possible to prevent the problem of dropping out.

In addition, since the width of the taper provided at the entrance of the assist spring insertion hole of the holding member is set to be larger than the distance between the assist spring lines at the time of setting the most advanced angle position, the inclination of the holding member and the rotor operation Due to the contraction of the assist spring, even when the assist spring strand crosses the entrance portion of the holding member, the assist spring strand does not get caught on the edge of the entrance portion of the holding member and generates a normal assist spring load. It is possible to suppress the tilting of the holding member. In addition, it is possible to suppress wear due to rubbing of the outer side of the assist spring wire with the entrance.

In addition, since the assist spring is arranged so that the assist spring is straight at the most advanced angle position where the assist spring set length is maximum, the assist spring and the holding member can be stably set, and the holding member at the time of assembly can be set. The rattling (tilt) can be minimized. Further, since the assist spring set length is set to be straight in the most unstable and easily deformable state, the assist spring can be prevented from being deformed into a U shape.

The valve timing adjusting device according to the present invention is attached to an exhaust side camshaft of an internal combustion engine and is effective when applied to control the opening / closing timing of the exhaust valve.

Claims

A camshaft for opening and closing a valve of the internal combustion engine; a case having a plurality of shoes on an inner peripheral surface thereof rotatably provided on the camshaft; and rotationally driven by the output of the internal combustion engine; A rotor having a plurality of vanes forming a retard hydraulic chamber and an advanced hydraulic chamber on both outer circumferential wall surfaces, housed in the case so as to be relatively rotatable and coupled to the camshaft In a valve timing adjustment device comprising:
A recess provided facing the circumferential wall surface of the shoe and the vane of the advance hydraulic chamber;
A holding member inserted and disposed in the recess from the axial direction;
An assist spring disposed between the shoe-side holding member and the vane-side holding member and biasing the rotor in an advance direction;
The clearance formed from the axial length of the holding member provided on the vane side and the axial length of the case is increased in consideration of the inclination of the holding member caused by the gap between the holding member and the recess. The valve timing adjusting device is set to be equal to or greater than the sum of the minute and the increase due to thermal expansion.
2. The valve timing adjustment according to claim 1, wherein a retaining portion for narrowing an opening is provided in a concave portion provided on a circumferential wall surface of the vane, and a tapered portion is formed on the holding member so as to contact the retaining portion. apparatus.
2. The valve timing adjusting device according to claim 1, wherein the width of the tapered portion provided in the holding member is set to be larger than the distance between the assist spring lines when the most advanced position is set.
2. The valve timing adjusting device according to claim 1, wherein the bottom surfaces of the shoe-side and vane-side holding members are parallel to each other at the most advanced position where the assist spring set length is maximum.