JP2003521624A - Automatic valve clearance adjustment device - Google Patents

Abstract

Abstract: An internally threaded housing (1); and having an externally threaded screw member (3) extending into the housing; the thread (4) of the screw member (3) is , Which is complementary to the shape of the thread of the female screw (2) of the housing, has an external shape that fits inside the housing with a predetermined gap in the axial direction, and has a trapezoidal shape and a symmetrical axial cross section. And exhibit equal frictional resistance to movement in both axial directions; the flank angle, torsion angle, and number of threads of the thread are determined only by the effect of the axial force applied to the end of the thread within the housing. It is selected to ensure that it rotates and moves axially out of the housing; the projecting end (7) of the screw member works with an adjacent component to provide a frictional resistance to rotation from this component. A valve that is adapted to receive Aransu automatic adjusting apparatus.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an automatic valve clearance adjusting device for a valve operating mechanism that can be used in an internal combustion engine or the like.

The adjustment device of the present invention comprises a female threaded housing, a male threaded screw extending into the housing, and an axial action on the screw to rotate the screw to open the housing. To the outside to extend the adjusting device. The shape of the thread cooperating with the screw and the housing is such that the screw freely rotates due to the bias due to the axial force and advances to the outside of the housing.

Such a valve clearance adjusting device is arranged in the space between two relatively movable components of the valve actuation mechanism, the housing engages with one component and the screw engages with the other component. When mated, this adjuster expands
That is, by moving the screw member out of the housing, the screw member operates so as to close the gap in the valve operating mechanism and completely fills the space between the constituent members. The adjusting device may be arranged, for example, directly or indirectly between the cam and the valve or valve actuating member. In another configuration, the adjustment device may provide a fulcrum for the lever-type valve actuating member, the position of the fulcrum being modified by the adjustment device to close the actuation gap.

[0004]   Corresponding reference characters are used for corresponding parts in all claims.

The following is a background of the invention, including some examples of the prior art and aspects of the invention itself:
Description will be made by way of example with reference to the accompanying drawings.

First, the automatic valve clearance adjusting device shown in each of FIGS. 1, 2 and 3 includes a housing 1, an internal thread 2 formed in the housing, and an external thread 4 that cooperates with the internal thread 2 of the housing. And a screw member 3 having. Reference numeral 5
Represents the axial force exerted by the spring means on the end 6 of the screw member located in the housing. This force is preferably applied by a compression spring engaging a threaded member, as described below. Reference numeral 7 indicates the end of the screw member projecting to the outside of the housing 1. This end 7 should then open the valve, depending on the nature of the valve actuating mechanism, either for transmitting the valve actuating force or against the spring force closing the valve by actuation of the cam on the camshaft. It engages a cooperating portion of the valve actuation mechanism to provide the necessary reaction force.

In the example shown in FIG. 1, the adjusting device is self-contained and is fixed in the socket of the engine body. The protruding valve actuating end 7 of the screw member 3 has a dome-shaped end with a spherical surface, which fits inside the hole 9 of the cam follower 8. Since the cross section of the hole 9 is spire arched or conical, the hole 9 and the dome-shaped end 7 meet in a circular strip. As the cam 10 rotates, the cam follower 8 oscillates about the axis provided by the dome-shaped end 7 and thus the valve stem 1
1. Actuate the engine valve via 1.

In FIG. 1, the lower end of the housing 1 is open. This would be suitable if the force 5 were hydraulically applied. If the force 5 were applied by a spring, one end of the housing would be closed, as will be described below.

The adjusting device shown in FIG. 2 is incorporated into a "bucket" type cam follower.
In this adjusting device, the housing 1 is preferably integrated with the bucket 13. The valve operating end 7 of the screw member 3 is shaped so that the contact area with the valve stem 14 is circular, annular or conical. In the valve actuation mechanism of this design, the bucket 13 is slidably attached to the inner diameter of the engine body. The cam 10 operates directly via the bucket 13 and the adjusting device to provide the valve 14 with a downward valve actuating action.

In the example shown in FIG. 3, the adjusting device is self-contained and acts as a movable push rod between the cam 15 and the rocker arm 17. The adjusting device is slidably attached to the inner diameter of the engine body. The adjuster imparts downward valve actuating action to the valve 18 by transmitting movement from the cam 15 to a rocker arm 17 which is pivotable about an axis 41. In this adjusting device, a pressing pad 16 is attached between the rocker arm 17 and the valve operating end 7 of the screw member 3.
In the housing 1, this pressing pad is slidable in the axial direction, but its rotation is suppressed.

In addition to the design described above, it would be possible to incorporate this regulator into other types of valve trains. For example, in a rocker arm / push rod mechanism, the housing 1 of the adjusting device could be integrated with the rocker arm.

Here, a known prior art will be described with reference to FIGS. 8, 9 and 10. As described above, the valve clearance adjusting device shown in each drawing is mainly constituted by a screw provided in a female-threaded housing. In each figure, each valve clearance regulator is shown with a schematic depiction of a type of engine valve mechanism in operative relationship with the regulator. The logic developed below applies to any other valve train.

In one class of prior art, there are several simple operating principles in which the above-mentioned screw is not acted upon by axial forces but is rotated by the action of a torsion coil spring to be advanced outside the housing. There are variants of. This principle will be described with reference to FIG. In FIG. 10, a cam 10 of the engine has an engine valve 39.
It is in the closed angular position as shown in. Further, FIG. 10 shows a torsion coil spring 2
As a result of 9 rotating the screw 30, one or more positions (A, B,
(C, D, etc.) the screw 30 is shown advanced to the outside of the housing 38 so as to eliminate any previously existing clearance. As further shown in FIG. 10, the transmission path of the compressive force is from the bottom 31 of the housing 38, through the threads in contact (eg, indicated at 33), and further at A, B, C and D. Through the position, it continues uninterrupted to the upper end of the valve stem 34 of the engine. Therefore, due to the difference in the coefficient of thermal expansion of various engine parts, the situation where the valve is not closed (
For example, reference numeral 40 in FIG. 9) may occur, leading to wear of parts and deterioration of engine performance. This is a serious drawback in all valve clearance adjusters that function by the action of torsion coil springs.

Another class of prior art (British Patent Publication No. 2033472, EP-T-00)
32284, British Patent Application Publication No. 2160945, British Patent Application Publication No. 221.
1263, International Application Publication No. 89/05898, International Application Publication No. 90/107
No. 86, International Application Publication No. 90/10787), the male screw and the female screw described above have a saw-tooth shape. This is a feature common to this whole class. Such a shape is shown in FIG. 8 which depicts an axial cross section of the screw 3 and the housing 1. The flanks 24H and 24S of the sawtooth screw having a slope G _R with respect to the line perpendicular to the axis are referred to as "running flanks". The inclination degree for a line perpendicular to the axis of the flank 25H and 25S of buttress thread is G _L is referred to as "pressure flank (locking flank)". Z represents a twist angle.

The engine cam 10 shown in FIG. 8 is in an angular position which closes the engine valve 11 as indicated by reference numeral 39. In addition, in the state shown in FIG. 8, in order to reduce the gap that may have been present at one or more positions (A, B, C, D, etc.) of the engine valve mechanism to zero, the compression spring 22, the play side flank of the screw 24S
Press to bring it into contact with the free flank 24H of the housing, and screw the screw 3 into the housing 1
To the outside of. Hereinafter, advancing the screw 3 to the outside of the housing is referred to as a "take-up" movement.

[0016]   In the situation shown in FIG. 9, the angular position of the engine cam 10 is changing, and
The force given by the gin cam is the valve stem 11 and the screw 3 of the valve clearance adjusting device.
Receive a reaction from. Due to the reaction on the valve stem, the valve is at 40
It is opened as shown. Also, due to the reaction to the screw, the flank on the pressure side of the screw
25S is a pressure side flank 25H of the housing through a gap (reference numeral 26 in FIG. 8).
Is pressed against and brought into contact with it. Theoretically, the flank inclination angle G of the pressure side _L The high frictional resistance due to the relatively large
In this case the screw 3 and the housing should be prevented as it should be prevented from retracting into the ging.
The assembly of group 1 should together resist the above reaction.

In summary, theoretically, utilizing a serrated screw provides a large resistance to the screw 3 being pushed inside the housing when subjected to an axially applied force,
It should be ensured that the resistance to the screw going out of the housing is low.

However, practical tests have shown that attempts to put the above-described operating principle into practice have some problems. The problem will be described below.

The presence of a predetermined axial gap between the screw thread on the screw side and the screw thread on the housing side is essential. Because, as indicated by reference numeral 26 in FIG.
This clearance ensures that there is nothing that prevents the valve from closing. A further circumferential clearance (19 in FIG. 4) is required between the crests of the threads and the adjacent roots to ensure the free movement of the screws in the housing. Therefore, as a result of the lateral displacement of the screw 3, the screw 3 may be eccentric with respect to the housing 1 as shown in FIG. 11 or may be inclined with respect to the housing as shown in FIG.
With the screw in either of these positions, if the play flank of the thread of the screw and the play flank of the thread of the housing are pressed against each other by the action of the spring 22, if the play flank 35 of the play flank surface occurs. If (Fig. 11) is too close to being perpendicular to the line of action of the force exerted by the spring 22, there is little tendency for the screw to return to its concentric position. A basic illustration of this is shown in FIGS. 13 and 14. 13 and 14 are enlarged views of the portion indicated by the symbol F in FIGS. 11 and 12. In the example shown in FIG. 13, the flank angle G _R is drawn with a small inclination. In another example shown in FIG. 14, the flank angle G _R is drawn with a larger inclination. Reference numerals 36 and 37 respectively denote the flanks 2 of the idle side of the screw.
4S and the housing flank flank 24H. When these two examples are respectively under the same friction condition, the force P is greater than that of the example of FIG.
In the above example, the movement Q could be easily generated. The movement Q is necessary to bring the screw back into the center of the housing 1.

Therefore, as confirmed by the practical test, when the inclination angle of the play side flank is small, the screw 3 is likely to remain in the housing 1 in an unfavorable position as shown in FIG. 11 or 12. . At the unfavorable position shown in FIGS. 11 and 12, the idle flank of the screw thread of the screw only makes a line contact or a point contact with the idle flank of the screw thread of the housing, and the adjacent “face-to-face” through the oil film Contact (ie boundary lubrication condition) cannot occur. As a result, there is a high frictional resistance that counters (and in most cases blocks) the "advance" movement. Although it is common practice to lubricate the threads with oil from the pressure of the engine's lubrication system, it is possible to maintain the necessary adjacent oil film lubrication under the conditions of point or line contact described above. Because it cannot do so, it causes excessive friction, which prevents the “advance” movement, or at most slow movement.

Conversely, if the pressure flank 25S of the thread of the screw and the pressure flank 25H of the thread of the housing are both matched by the force opening the valve (see FIG. 9), the angle of the pressure flank is This is the preferred angle for centering the screw in the housing. In this case, there may be an adjacent oil film lubrication condition and the movement of the screw 3 inside the housing 1 (“back-off” move (“back-off” move)).
)) instantaneously, that is, until the compressive force acting between the engaging pressure flanks breaks the oil film and causes metal-to-metal contact.

In summary, theoretically, the pressure side flank / the play side flank have high friction /
Despite the low friction, the "reverse" movement may be too large and / or the "advance" movement may be too small. If the "retract" action exceeds the "extend" action in each valve closing / opening cycle, the screw 3 will gradually retract into the housing 1 and contact between the members of the valve train will be lost.

In addition to the performance drawbacks described above, there are manufacturing problems. Also,
When using a sawtooth screw, there is also a problem of durability in use. These problems will be described below.

The above-mentioned axial gap (reference numeral 26 in FIG. 8 and reference numeral 9 in FIG. 9) needs to be kept within a strict range by strict control when manufacturing the male screw and the female screw. If this gap is too large, the valve will not operate sufficiently and the noise will increase. 8 and 9
15 and, typical values for G _L and G _R are 75 ° and 15 °, respectively. When the radial gap (KM in FIG. 15) is represented by a symbol C, the axial gap is JK + KL = (C × tangent 15) + (C × tangent 75), that is, four times C. This means that, for example, when the tolerance of the axial gap is 0.1 mm, it is necessary to set the total diameter tolerance of the male screw and the female screw to about 0.05 mm. This is a very difficult requirement for mass production.

A similar situation exists with regard to thread surface wear during use. If the radial clearance is slightly increased by eroding the surface of the inclined flanks or flattening the surface roughness, the axial clearance will be increased by a factor of four. Also in this case, the valve does not operate sufficiently and the noise becomes loud.

GB-A-2211263 discloses the provision of grooves and ridges on the pressure flank of a screw. This design change was introduced in an attempt to keep "backward" motions within an acceptable range. The intent of this design is that the low surface area ridges more easily break the oil film between the engaging pressure flanks, allowing for faster metal-to-metal conditions, thereby increasing the magnitude of the "retraction" action. It is to reduce. However, this design has the following drawbacks.

[0027]     a. The production of pressure flanks with grooves and ridges is difficult.

B. The reduced contact area results in an increased rate of wear on the engaging pressure flanks. Therefore, the axial clearance increases as explained in the previous paragraph. Due to the strict diameter tolerances required for the threads of the components of the adjusting device (ie the threads on the screw side and the threads on the housing), the manufacture of the tools used to manufacture these components includes: Even tighter tolerances are required. In particular, this applies to threading taps for producing internal threads in the housing. Also,
The saw tooth cross-sectional ratio requires an extremely wide tap tooth, which is not preferable because it may increase the tapping torque.

Attempts have been made to increase the efficiency of engines with automatic valve clearance adjusters, with an emphasis on reducing the friction of the contact surfaces of the cam 10 and the cam follower 8.

One object of the present invention is to provide a mechanical valve clearance adjuster of the improved construction mentioned in particular below.

[0031]     a. Improve the reliability of the "advance" operation.

[0032]     b. Reduces friction between the cam and the cam follower.

[0033]     c. Occurs between mating male and female threads when the threads are serrated.         Make sure that the ratio of radial clearance / axial clearance does not become an undesired value.         To If this ratio is not desired, very tight manufacturing tolerances are required.         Not only that, but the axial clearance between the mating threads increases sharply.

A valve clearance adjusting device according to one aspect of the present invention includes a housing having a female screw threaded therein, and is substantially complementary to the shape of the female thread of the housing, and is spaced apart in the axial direction by a predetermined distance. The housing is provided with a screw member having a male screw shaped to fit in the housing. The thread is trapezoidal and symmetrical in axial cross section, and exhibits equal frictional resistance to movement in both axial directions. Flank angle of thread,
The helix angle and the number of threads are determined to ensure that the screw member rotates and advances axially outward of the housing only under the influence of axial forces applied to its non-protruding end. The protruding end portion of the screw member is shaped so as to act together with an adjacent component member (for example, a valve operating mechanism of an IC engine) and receive frictional resistance against rotation from the adjacent component member. The non-projecting side end of the screw is shaped so as to assist the axial movement of the screw member when subjected to the action of the axial force described above.

As one of the reasons why the “advance” operation becomes slow, FIG. 11 and FIG.
2 shows that the screw 3 tends to move to an eccentric position with respect to the housing 1. In the present invention, as described above with reference to FIGS. 13 and 14, this tendency is reduced by increasing the inclination angle G _R of the play flank.

To avoid requiring very close tolerances on the diameter of the thread,
As already mentioned with reference to 5, it is highly desirable to substantially reduce the ratio of axial clearance / radial clearance = tangent G _L + tangent G _R. For example, G _R from 15 ° to 3
When it is increased to 0 ° and G _L is decreased from 75 ° exemplified to 30 °, the ratio of the axial clearance ÷ the radial clearance is (tangent 15 ° + tangent 75
°) to (2 x tangent 30 °), ie from 4 to 1.15.

As described above, in the present invention, the flanks of the screw threads on the screw member side and the housing side are inclined at an angle of 30 ° on each side of a vertical line with respect to the axis of the screw thread when viewed from the axial cross section. It is preferable that These flank angles are found in modern threads such as those used in standard bolts and nuts, and are commonly referred to as 60 ° threads. This has the advantage that commonly available equipment can be used during the examination (eg microscope reticles, thread measuring needles, thread measuring machines, gap gauges and optical projection screens).

Therefore, the angle G _R of the play flank becomes equal to the angle G _L of the pressure flank (that is, G = G _R = G _L = 30 °). Assuming that the torsion angle is Z and the friction coefficient is μ, the condition for rotating the screw by the axial load and advancing it in the axial direction is expressed by the following equation.

Tangent Z> μ ÷ cosine G It is assumed that the friction on the screw end on the side receiving the axial force is negligible. As a schematic example, a screw with an outer diameter of 8 mm and a lead of 4 mm will rotate under axial load if the coefficient of friction value is less than about 0.14. Increasing the leads to 5 mm will allow full operation even with higher friction coefficients (ie 0.17).

As described above, it is possible to obtain a screw member having symmetrical threads with the flank angle G of 30 ° and capable of rotating and advancing in the axial direction only by the influence of the axial force. Furthermore, by setting the flank angle to 30 °, the screw member can stay in a position on a concentric circle with respect to the housing, so that the point contact condition that occurs when the flank angle is smaller as described above is avoided. It becomes possible. In this way, an "advance" movement can be achieved due to the influence of axial forces. Such axial force may be provided, for example, by hydraulic pressure from the engine's lubrication system or by a small spring, which is preferably acted on the end of the screw by means of a plunger with a ball at the end as a medium. it can.

According to a practical test, when the screw member is formed into a symmetrical “V” shape, the external friction torque resistance is applied to the screw end portion of the valve operating mechanism of the engine which comes into contact with the cooperating member so that the screw member is screwed. Has been proven to be sufficiently resistant to the "backward" movement.

According to the design of the engine valve mechanism, the contact portion between the end portion of the screw member and the cooperating member of the valve mechanism can have the following shapes, for example.

A. Circular line b. Annular region c. One area on the curved surface of a thin truncated cone d. A region on the curved surface of a thin piece of a sphere b. c. Or d. In that case, the width dimension may be small enough to satisfy the assumption that the contact condition is a circular contact line. In all cases, the axis of the circle is perpendicular to the plane and coincides with the central axis of rotation of the screw member. In each of the above four examples, the value D represents the diameter of the circle on which the frictional resistance acts tangentially. Assuming that the average diameter of the screw thread is d, the external frictional resistance to the "backward" motion is mainly D ÷
It depends on the ratio of d. Therefore, this frictional resistance can be controlled by the following designs I to III.

I. Average diameter of screw II. Valve operating end of screw member III. A part of the valve mechanism that contacts the screw member. For example, when the ratio of D / d is 2 and the twist angle of the screw thread is 10 °, the adjustment device “
Engine tests have demonstrated that the "reverse" movement is properly controlled. Along with this, a “progress” operation with high reliability and high responsiveness is obtained.

Next, the operation method of the adjusting device according to the present invention will be described with reference to FIG.
A description will be given with reference to a), FIG. 5 (b), FIG. 6 (a), FIG. 6 (b), and FIG. 7 (a), FIG. 7 (b). FIG. 5A shows a conceptual position of the screw member 3 in the housing 1 when a gap is generated between the members of the valve operating mechanism of the engine. In order to facilitate the explanation, the entire clearance amount is set to the end portion 7 of the screw member 3 and the hole 9 of the cam follower 8.
Shown as a single gap 42 formed between and. In this situation, the cam 10 can be in any position as long as it is in an angular position where a constant radius portion is in contact with the cam follower 8, as shown diagrammatically in FIG. 5 (b). is there. Due to the relatively large helix angle and due to the low friction torque resistance between the ball 29 and the spherical recess at the end 6 of the screw member, the spring 22 causes an "advancing" movement, i.e. It is possible to advance the screw member 3 to the outside (upper side in the figure) of the housing 1 until the spherical end portion 7 contacts the surface of the hole 9 of the cam follower 8 as shown in FIG. 6 (a).

[0046]   In the situation shown in FIG. 6A, it is necessary to pay attention to the following three points.

A) The cam 10 may still be in any position as long as it is in an angular position where a constant radius portion is in contact with the cam follower 8, as shown diagrammatically in FIG. 6 (b). Can be considered as possible.

B) On the lower side of the thread of the screw member 3 in the drawing, the gap 43 is maintained as in the situation shown in FIG. 5A.

C) The force exerted by the spherical end 7 on the surface of the hole 9 of the cam follower 8 is small. This force is limited to the force of the spring 22 minus the force required to produce the "advance" action.

In the situation shown in FIGS. 7A and 7B, the position of the cam 10 has changed,
In this state, the cam follower 8 is pushed by the amount by which the screw member 3 is lowered through the gap 43 which has been present. That is, this time, the gap is above the thread of the screw member 3 (
(Indicated by reference numeral 44). At this time, there is a continuous oil film between the mating threads, so that the housing 1 for an upward "retraction" movement of the screw member 3 is carried out.
The resistance from the inside decreases. Therefore, the resistance to the "retraction" action is due to the friction at the contact between the end 7 of the screw member and the surface of the hole 9 of the cam follower 8.
Given from the outside.

When the cam 10 is continued to rotate a little, the load on the entire valve mechanism suddenly increases in order to overcome the force pressing the engine valve against the valve seat. The aforementioned oil film between the mating threads is broken, and the friction at the threads provides resistance from the inside to the "retraction" action.

According to a given thread profile and friction conditions, the above-mentioned resistance to the "backward" movement from the outside depends mainly on the ratio of D / d (D being the end 7 of the screw and the cam follower 8).
Is the effective diameter of the circle in which the surface of the hole 9 comes into frictional contact, and d is the average diameter of the thread). Therefore, the required resistance to "backward" operation is provided by the following I-III designs.

I. Thread (for effective diameter) II. Valve operating end 7 of screw member 3 III. A part of the valve mechanism that contacts the end 7 of the screw member 3. Further, the resistance to the "retraction" operation can be increased by increasing the angle W (FIG. 6A). This angle W is the angle between the common tangent to the contact surface of the hole 9 and the spherical end 7 and the horizontal plane.

Further rotation of cam 10 causes the engine valve to open and then close,
Then, the valve mechanism returns to the state corresponding to FIG. 5 (a) or FIG. 6 (a).

The valve clearance automatic adjusting device of the present invention is not incorporated in the valve operating mechanism (
That is, unless incorporated into the engine) and, thus, unrestrained by the engaging valve actuation mechanism components, the force applying means may advance the screw member to the maximum extent outside the housing. In this state, the adjusting device cannot be installed in the engine, so that the screw member is moved into the housing by rotating the screw member with respect to the housing, and the adjusting device is arranged between the related components. It is necessary to shorten the total length of the adjusting device. For a valve actuating mechanism of an engine having a plurality of valves, when such a plurality of adjusting devices are installed at predetermined positions of individual parts, these adjusting devices are temporarily installed to facilitate the assembling work. Clearly, it is desirable to have some means of holding the contracted state.

In a broad sense, the purpose of another aspect of the invention is to meet the above requirements for temporarily holding the adjusting device in the contracted state.

Applicants thus, in accordance with another aspect of the present invention, a housing having an internal thread, a threaded member having an external thread extending from an open end of the housing into the housing and engaging a thread on the housing side, and a screw Spring means acting on the screw member in the longitudinal direction of the member; cooperating thread shapes of the screw member and the housing such that the spring member causes the screw member to rotate and advance outside the housing An abutment means operable between the screw member and the housing when the screw member is screwed into an inner position within the housing, whereby the abutment means is provided between the screw member and the housing and the abutment means. And a valve clearance adjusting device capable of producing sufficient frictional force to hold the screw member in the inner position against the action of the spring means.

In the valve clearance adjusting device according to this aspect of the present invention, the screw member can be screwed up to an inner position in the housing that engages the abutment means operable between the screw member and the housing. After that, when the screw member is tightened to increase the force applied between the screw member, the abutment means, and the housing, between these three,
A frictional force of sufficient magnitude is created to resist the action of the spring means which tends to push the screw member out of the housing. The dimensions of the valve clearance adjuster should be small enough to allow the adjuster to be easily installed in the required position within the engine valve actuation mechanism when the threaded member is in the inward position. This makes it possible to easily assemble an engine equipped with a plurality of valve clearance adjusting devices. As evidenced by testing, when the engine is started, each regulator causes enough impact to release the friction lock between the screw and the housing by a collision from a cam that activates a particular valve. Therefore, the screw member immediately assumes the correct operating position with respect to the housing of the adjusting device.

The screw member of the adjusting device may be adapted to engage a tool capable of screwing the screw member into the housing for actuating the abutment means as described above. In the adjusting device embodiment described below, the screw member has a head with a partially spherical surface, which engages a complementary partially spherical socket provided on a rocker arm or the like. . In this embodiment, the tool for engaging the threaded member may include a socket or recess having a particular surface profile. The surface shape of the socket or the recess is such that the head portion of the screw member can be frictionally engaged to such an extent that the screw is tightened so as to engage with the abutment means when the screw is in the inner position.

The abutment means may be provided in the housing and may be provided in the housing having a shoulder engageable with the innermost end surface of the screw member when in the inner position. Such a shoulder may be provided by the housing itself. Alternatively, a separate member providing such a shoulder (eg, a sleeve) may be inserted within the housing.

Alternatively, the screw member may be provided with an abutting portion that is engageable with the end surface of the housing. Such an abutment may include a collar provided under the head of the screw member. Such a collar may be used for holding the screw member when screwing the screw member into the housing and for tightening the screw member after the flange is engaged with the housing. Then there is no need to use another tool in this case.

The valve clearance adjusting device is preferably according to the first aspect of the present invention.
Alternatively, however, it could be an adjusting device incorporating sawtooth screws as mentioned in the above description of the prior art.

FIG. 16 shows an adjusting device such as that shown in FIG. 5 (a), FIG. 6 (a), or FIG. 7 (a) in a possible state when it is not installed in the engine. The screw member extends out of the housing and the total length of the adjusting device is substantially larger than the space that the adjusting device can occupy in the engine.

Therefore, in order to install this adjusting device in the engine, it is necessary to screw the screw member 3 into the housing 1 so that the total length of the adjusting device is shortened to a size that facilitates installation. The total length of such a regulator is slightly shorter than the typical working length of the regulator shown in Figures 6 (a) and 7 (a).

Depending on the characteristics of the threads acting between the screw member of the adjusting device and the housing, the screw member may not stay in such an installed position due to friction. In such a case, in accordance with the invention, abutment means may be provided between the screw member and the housing when the screw member is in the innermost position similar to the position shown in Figure 5 (a). . One form of such abutment means is provided by a cylindrical sleeve 50 provided within the housing and surrounding the spring 22, as shown in FIG. Sleeve 5
One end of 0 engages a closed end 51 on the lower side of the housing, and the other end of the sleeve abuts an annular portion surrounding the recess of the end face 6 of the screw member.

A spring 22 is provided between the screw member and the sleeve and between the cooperating threads of the screw member and the housing when the screw member is screwed into the housing and is engaged by engaging the abutment sleeve 50. A force for holding the screw member in the innermost position is generated by friction against the force applied to the screw member. This allows the adjustment device to be easily attached. However, when the engine with this adjusting device is started, the screw immediately assumes the correct operating position described above, because the cam provides sufficient collision to release the friction lock between the screw member and the housing. .

Instead of the sleeve 50, it is possible to integrally provide an abutting portion that can engage with the screw member at the innermost position with the housing. Such an abutting portion can be provided by, for example, reducing the inner diameter of the portion of the housing below the lower end of the female screw in which the spring 22 is housed. Yet another possibility is to provide an outer collar below the head of the screw member, which is engageable with the outer end surface 55 of the housing. Such a collar may be used as a means for rotating the screw if it is necessary to screw the screw into the housing until the collar abuts the housing.

If the collar is not provided with a collar or other component that allows the threaded member to be screwed into the housing in this way, the end portion 7 with a partially spherical head of the threaded member. As a tool for engaging with and rotating the screw member, a tool indicated by reference numeral 52 in FIG. 17 may be used. One end of the tool 52 has a tapered socket 53
And the angle is such that when the tool is manually pushed into engagement with the head of the screw member, the screw member is screwed into the housing against the action of the spring 22 and engages the abutment sleeve 50. The angle is such that the screw members are frictionally gripped with sufficient force to fit. The tool 52 is provided with a grip 54 that allows the user to hold the tool and rotate it easily.

As mentioned above, in some designs of the adjusting device incorporating spring means for axially advancing the screw member to the outside of the housing, in some designs, the adjusting device is assembled to the engine. The above-mentioned means may not be necessary to facilitate the integration. As mentioned above, when the D / d ratio is 2 and the thread helix angle is 10 °, the "retracting" movement of the adjusting device is properly controlled, which is accompanied by a reliable and responsive reaction. Engine testing has proved that the "advancing" behavior of the regulator is obtained.
However, in consideration of the design of the entire engine, it is necessary to consider reducing the helix angle of the thread when the D / d value is limited to a low value. For example, an adjuster that requires a helix angle of 6 ° should produce a proper “advance” action when subjected to effective lubrication in the engine, but even if no assembly equipment is required, the screw There should be sufficient thread friction to hold it in the inner position in the housing.

In the present specification, “comprise” means “includes or c”
onsis of ”, and“ comprising ”means“ inclus
"ding or consistent of".

The features disclosed in the above description or in the following claims or the accompanying drawings are based on specific embodiments, or means for performing the disclosed functions or methods or processes for achieving the disclosed results. However, these features may be used, alone or in combination, to implement the invention in various forms.

[Brief description of drawings]

FIG. 1 is a diagram showing a possible arrangement of a valve clearance automatic adjustment device in a valve actuation mechanism of an internal combustion engine.

FIG. 2 is a diagram showing a possible arrangement of a valve clearance automatic adjustment device in a valve actuation mechanism of an internal combustion engine.

FIG. 3 is a diagram showing a possible arrangement of a valve clearance automatic adjustment device in a valve actuation mechanism of an internal combustion engine.

FIG. 4 is an enlarged cross-sectional view of a thread in an adjusting device (which may be according to the invention).

5A is a diagram showing a part of an adjusting device and a cam follower when it is required to close a gap of a valve mechanism by an automatic valve clearance adjusting device according to the present invention, and FIG. It is a figure which shows the cam position relevant to Fig.5 (a).

6A is a diagram showing the adjusting device in a state immediately after the valve clearance adjusting device of FIG. 5 has made the gap of the valve operating mechanism to zero, and FIG. 6B is a diagram showing the adjusting device in FIG. 6A. It is a figure which shows the related cam position.

FIG. 7A is a view showing a part of the valve clearance adjusting device and the cam follower of FIGS. 5 and 6 in a state immediately after the valve mechanism starts opening the valve, and FIG.
The figure is a diagram showing the cam position related to FIG.

FIG. 8 is a view showing a valve clearance automatic adjusting device according to the prior art, and a gap that may have existed at one or more positions (A, B, C, D, etc.) of the engine valve mechanism. Shows the state immediately after being packed by the adjusting device.

[Figure 9]   It is a figure which shows the state in the valve opening operation of the adjusting device of FIG.

FIG. 10 is a view showing an automatic valve clearance adjusting device according to another embodiment of the prior art.

FIG. 11 is a view showing a state in which the screw is laterally displaced in the housing of the adjusting device in the valve clearance adjusting device of FIGS. 8 and 9;

FIG. 12 is a view showing a state in which the screw is obliquely displaced in the housing in the adjustment device of FIGS. 8 and 9.

FIG. 13 is a view showing a part of flanks that come into contact with each other when the fitted thread flank angle is relatively small.

FIG. 14 is a view showing a part of flanks that come into contact with each other when a flank angle of a thread to be fitted is relatively large.

FIG. 15 is a diagram showing a part of a thread to be fitted, showing a relationship between a clearance between threads in an axial direction and a radial direction.

FIG. 16 is a view showing a possible position before the adjusting device of the present invention is installed in an engine.

FIG. 17 is a diagram showing a valve clearance automatic adjustment device according to another aspect of the present invention in a state ready to be incorporated into an engine.

[Procedure for Amendment] Submission for translation of Article 34 Amendment of Patent Cooperation Treaty

[Submission date] February 14, 2002 (2002.2.14)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Contents of correction]

[Claims]

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), OA (BF , BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, G M, KE, LS, MW, MZ, SD, SL, SZ, TZ , UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, B Z, CA, CH, CN, CR, CU, CZ, DE, DK , DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, J P, KE, KG, KP, KR, KZ, LC, LK, LR , LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, R O, RU, SD, SE, SG, SI, SK, SL, TJ , TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW F term (reference) 3G016 AA05 AA06 AA19 BA18 BA19                       BB04 BB09 BB18 BB23 BB30                       BB31 BB32 BB39 BB40 CA05                       CA07 CA10 CA11 CA12 CA16                       CA25 CA27 CA33 CA45 CA46                       CA52 DA13 DA17 DA18 DA19                       DA20 DA22 FA27 FA37 FA38                       GA01 GA02 GA04

Claims (23)

[Claims] 1. A female threaded housing (1); a male threaded screw member (3) extending into the housing; a thread (4) of the screw member (3) comprising: Complementary to the shape of the threads of the female thread (2) of the housing, it has an external shape that fits inside the housing with a predetermined gap in the axial direction. The shape is trapezoidal and the axial section is symmetrical. Yes, exhibiting equal frictional resistance to movement in both axial directions; the flank angle, helix angle and number of threads of the screw thread rotate only by the action of the axial force exerted by the screw member on the end in the housing To axially extend outside the housing; the projecting end (7) of the screw member acts with an adjacent component to receive frictional resistance to rotation from this component. Valve that is adapted to Clearance automatic adjustment device. 2. The valve clearance automatic adjusting device according to claim 1, wherein flanks of the screw threads on the screw member side and the housing side are inclined at an angle of 30 ° with respect to a line perpendicular to the axis of the screw threads. . 3. An urging side end portion of a screw member, the adjacent component member, (a) a circular line, (b) an annular region, (c) a region on a curved surface of a thin truncated cone, as well as,
(D) The adjusting device according to claim 1 or 2, which is adapted to contact in any one part of one region of the curved surface of the thin piece of the spherical body. 4. When contacting with the adjacent component member at b, c or d,
Adjusting device according to claim 3, wherein the contact area approximates a line contact. 5. The adjusting device according to claim 3, wherein the diameter of the contact line or the contact area is larger than the average diameter of the threads of the adjusting device. 6. Adjusting device according to any one of the preceding claims, comprising spring means acting on the screw member for biasing the screw member axially towards the outside of the housing. 7. The adjusting device according to claim 6, wherein the spring means acts on the end of the screw member in the housing through a member having a ball at the end. 8. The adjusting device according to claim 1, wherein the threaded member is adapted to be acted upon by a hydraulic pressure that urges the threaded member axially outward of the housing. 9. Abutment means is provided between the threaded member and the housing when the threaded member is screwed into an inner position within the housing, whereby the abutment means is provided.
Adjusting device according to claim 6 or 7, wherein between the abutment means of the screw member and the housing there may be sufficient frictional force against the action of the spring means to hold the screw member in the inward position. . 10. A housing having an internal thread, a threaded member having an external thread extending from the open end of the housing into the housing and engaging a thread on the housing side, and acting on the threaded member in the longitudinal direction of the threaded member. Spring means; the shape of the cooperating threads of the screw member and the housing is such that the action of the spring means causes the screw member to rotate to the outside of the housing; There is provided an abutment means operable between the screw member and the housing when screwed into the housing, whereby the abutment means between the screw member and the housing resists the action of the spring means. A valve clearance adjusting device that can generate sufficient frictional force to hold a member in an inner position. 11. The adjusting device according to claim 9, wherein the abutment means is provided in the housing, and is constituted by a shoulder portion engageable with the innermost end surface of the screw member. 12. The adjusting device according to claim 11, wherein the shoulder is provided by a housing. 13. The adjustment device of claim 11, wherein the shoulder is provided by a member disposed within the housing. 14. The adjusting device according to claim 9, wherein the screw member has an abutment portion that can be engaged with the end surface of the housing. 15. The adjusting device according to claim 14, wherein the abutting portion includes a collar provided below a head portion of the screw member. 16. The adjusting device according to claim 15, wherein the collar is provided to hold the screw member for screwing the screw member into the housing. 17. The threaded member is adapted to be engaged by a tool for screwing the threaded member into the housing and actuating the abutment means. Adjustment device according to. 18. A combination of the adjusting device according to claim 17 and the tool engageable with the device. 19. The combination of claim 18, wherein the tool is capable of frictionally engaging the head of the screw member. 20. The valve clearance automatic adjusting device according to claim 1, wherein the valve clearance automatic adjusting device is arranged between the constituent members of the valve actuating mechanism in order to close the gap between the constituent members. Valve actuation mechanism including. 21. An internal combustion engine including a large number of valve operating mechanisms according to claim 20. 22. A valve clearance automatic adjustment device substantially as described above with reference to FIGS. 5-7 or 17 of the accompanying drawings. 23. Any novel feature or novel combination of features described herein and / or in the accompanying drawings.