KR20030041853A - Automatic valve clearance adjuster - Google Patents

Abstract

The present invention provides a screw-threaded housing (1) therein; A screw-threaded screw member 3 extending outwardly in the housing, the screw thread 4 of the screw member 3 being a complementary and predetermined axis to the thread form of the inner thread 2 of the housing. Has an contour that fits into the directional gap, the thread is trapezoidal in shape, symmetrical in axial cross section, and exhibits the same frictional resistance to axial movement; The flank angle, the spiral angle, and the number of screw threads at the start are determined in the housing to ensure that the screw member rotates and advances axially from the housing only under the influence of the axial force on its end; The exposed end 7 of the screw member relates to an automatic valve clearance adjuster characterized in that it is adapted to operate to accommodate frictional resistance to rotation in relation to adjacent components.

Description

Automatic Valve Gap Regulator {AUTOMATIC VALVE CLEARANCE ADJUSTER}

This valve clearance regulator is located in the gap between two relative movable components of the valve actuation mechanism and when the housing connects one component and the screw connects another component, the regulator advances and extends the screw member from the housing so that Raise the clearance of the valve actuation mechanism until it fully occupies the clearance between components. Through this embodiment, the adjuster is to be adjusted directly or indirectly between the cam and the valve or valve actuating member. In another arrangement, the adjuster provides a lever for the lever type of the valve actuating member, the position of the lever being changed by the regulator to widen the operating gap.

Background of the Invention The prior art includes certain prior art and features of the invention itself and will be described below with reference to the drawings.

The present invention relates to an automatic valve clearance regulator for a valve operating mechanism used in fields such as an internal combustion engine, wherein the regulator includes a screwed housing therein, an externally threaded screw extending from the inside of the housing, and a shaft on the screw. A force exerting means for advancing and rotating outwardly of the open end of the housing which acts in the direction and extends the adjuster, wherein the threaded form of simultaneous actuation relationship of the screw and the housing is oriented in the axial direction. Under the bias of the force, the screw has a structure of free rotational movement as it moves forward from the housing.

1, 2 and 3 show possible arrangements of the automatic valve clearance regulator of the valve operating mechanism for an internal combustion engine engine,

4 is an enlarged cross-sectional view of a screw thread of a regulator according to the present invention,

Figure 5 shows an automatic valve gap regulator according to the invention, a cam follower associated therewith, as a diagram of the position of the associated cam, the regulator raises the gap in the valve train,

FIG. 6 shows the valve gap regulator of FIG. 5, showing the position of the associated cam, where the regulator removes the gap in the valve train,

FIG. 7 shows part of the valve gap regulator, cam follower of FIGS. 5 and 6, diagrammatically showing the position of the associated cam, where the valve train starts to open the valve,

8 shows an automatic valve gap regulator according to the prior art, which adjusts a gap already present in one or more positions, such as A, B, C, D of the engine valve train,

9 shows the regulator of FIG. 8 in a state when the valve is opened,

10 shows an automatic valve gap regulator according to a further embodiment of the prior art,

FIG. 11 shows the valve actuator of FIGS. 8, 9 with the screw located on the side in the housing of the regulator, FIG.

12 shows the adjuster of FIGS. 8, 9 with the screw in an angled position in the housing,

13 is a fragmentary view of the contact flank of a mating screw thread with a relatively small flank angle,

14 is a fragmentary view of the contact flanks of mating screw threads with relatively large flank angles,

15 is a fragmentary view of the complementary screw thread showing the relationship between the axial and radial thread clearances,

16 shows the position of a regulator according to the invention considered in the prior art in an engine,

17 shows an automatic valve gap regulator according to a further invention which is an assembly inside the engine.

In all claims, reference numerals have been used for corresponding parts.

In each of the figures in FIGS. 1, 2, 3 there is shown a screw with a housing 1, an inner screw thread 2 extending into the housing and an outer screw thread 4 working together with the inner thread 2 of the housing. An automatic valve gap adjuster with member 3 is shown. Reference numeral 5 shows a relationship in which the axial force is applied by the spring means to the screw member of the end 6 in the housing, which force is preferably applied by a compression spring connecting the screw member to be described below. . Reference numeral 7 protrudes outward from the housing 1 and provides a repelling force or transfers the valve actuation force according to the characteristics of the valve actuation mechanism required until the valve is opened against the force of the closing spring by actuation of the cam on the camshaft. To the end of the screw member which connects the component which acts like a valve actuation mechanism.

Looking at the example shown in FIG. 1, the regulator is self-mounted so that the engine is stationary at the socket of the body. The protruding valve actuating end 7 of the screw member 3 has a domed end with a spherical surface which is installed in a cavity 9 of the cam follower 8. The cavity 9 has a domed or conical cross section of a vault, thus forming a narrow circular band in contact with the domed end 7. As the cam 10 rotates, the cam follower 8 oscillates relative to the lever support provided by the domed end 7 to actuate the engine valve via the valve stem 11.

In FIG. 1 the housing 1 is shown as an open bottom end, in which case the force 5 is applied by hydraulic pressure. For the force 5 exerted by the spring, the housing has a closed end as will be explained below.

2 shows a regulator mounted on the "bucket" type of cam follower, the housing 1 preferably being integral with the bucket 13. The valve actuated end 7 of the screw member 3 forms a circular, annular, conical contact area with the valve stem 14. In this design of the valve actuation mechanism, the bucket 13 is mounted slidably in the bore of the engine body. The cam 10 operates directly via the bucket 13 and the regulator produces a downward valve actuation motion on the valve 14.

In FIG. 3, the adjuster itself is mounted and acts as a push rod moving between the cam 15 and the rocker arm 17. The regulator is slidably mounted in the bore of the engine's body. The regulator transfers motion from the cam 15 to the rocker arm 17, which can pivot about the shaft 41, and exerts a downward valve actuation motion on the valve 18. The adjuster is installed by the pressure pad 16 between the valve actuating end 7 of the screw member 3 and the rocker arm 17. The pressure pad slides axially in the housing 1 but the rotational movement is limited therein.

In addition to the design described above, the regulator can also be mounted to other types of valve trains. For example, the adjuster housing 1 may be an integral part of the rocker arm of the rocker arm / push rod mechanism.

Known prior art will be described in Figures 8, 9 and 10, each showing a valve clearance regulator which basically includes a screw inside the inner threaded housing as described above. In each case, the valve clearance regulator diagrammatically represents one type of engine valve train mechanism in which the regulator is in operation. The reason to be described below also applies to other valve train mechanisms.

In one type of the prior art, there are several variants according to the simple principle of operation in which the aforementioned screw is not operated by axial force and is advanced out of the housing under the action of a torsion spring. This is described with reference to FIG. 10 showing the cam 10 of the engine, which cam is shown in position to allow the engine valve to be closed as shown by 39. 10 also shows that the torsion spring 29 rotates the screw 30 to remove the pre-existing clearance at one or more locations, such as A, B, C, D, of the engine valve train. Shows that it moves forward. 10 also shows A, B, C, D from the base 31 of the housing 38 to the top of the stem 34 of the engine valve via a contact screw thread (as shown, for example, 33). The intact path of compression force transmission along the location is shown. Thus, the difference in thermal expansion of the various engine components prevents the valve from closing (eg, as shown in FIG. 9 (40)), causing component wear and degrading engine efficiency. This is a serious problem for all valve clearance regulators that function under the action of a torsion spring.

In the type of another prior art (GB-A-2033472, EP-T-0032284, GB-2160945, GB-2211263, WO-A1-89 / 05898, WO-90 / 10786, WO-90 / 10787), One inner and outer thread is buttress type, which is a common feature of this type. This shape is shown in FIG. 8 where the screw 3 and the housing 1 are shown in axial cross section. Buttress-type thread flanks 24H and 24S, shown at a slope of G _R with respect to the line perpendicular to the axis, are named "running flanks". Buttress-type thread flanks 24H and 24S, shown at a slope of G _L with respect to the line perpendicular to the axis, are named "locking flanks". Thread angle is Z.

8 shows the engine cam 10 in position to allow the engine valve 11 to close at 39. This also allows the compression spring 22 to push the drive flank 24S of the screw into contact with the drive flank 24H of the housing and to pre-exist in one or more positions, such as A, B, C, D, of the engine valve train. Advance the screw 3 out of the housing 1 to remove all gaps. Advancing the screw 3 out of the housing is referred to below as a "take-up" movement.

FIG. 9 shows a situation in which the engine cam 10 is switched to a position exerting a reaction force by the stem 11 of the valve and the screw 3 of the gap regulator. The valve stem opens the valve as shown at 40; The reaction on the screw exerts a force on the fastening flank 25S of the screw through the gap 26 of Fig. 8 to make contact with the fastening flank 25H of the housing. Theoretically, the assembly of the screw 3 and the housing 1 must behave as a solid in response to the reaction, because of the rotation of the screw and subsequent from the relatively large angle of the inclination of the fastening flank G _L into the housing. Because of the increased frictional resistance that must be avoided.

In sum, in theory, the use of buttress-type threads ensures high resistance to the screw being pressed into the housing under axial force and low resistance to the screw advancing out of the housing. .

It has been shown in the actual experiment that the actual experiment involves some problems as described below in the working principle described above.

There must be an axial gap in advance between the thread on the screw and the thread of the housing because there is no obstruction in the valve cap as shown in FIG. In order to allow the screw to move freely inside the housing, radial clearance is required between the thread and the adjacent threaded floor, as shown in (19) of FIG. Thus, as shown in FIG. 11, the screw 3 is located on the side to be eccentric to the housing 1 or to be inclined relative to the housing as shown in FIG. 12. In the screw in this position, when the traveling flank of the screw thread and the traveling flank of the housing thread are pushed toward each other under the action of the spring 22, the generator of the surface of the traveling flank (35 in FIG. 1) is the spring ( The screw tends to return to a slightly concentric position if it is very close vertically close to the line of action of the force exerted by 22). The basic drawing of this is shown in FIGS. 13 and 14. 13 and 14 are enlarged views of regions designated as F in FIGS. 11 and 12. In the example of FIG. 13, the flank angle G _R is represented by a small slope. 14 shows another example, shown as G _R with a large tilt angle. Reference numerals 36 and 37 show the elements of the running flank 24S of the screw and the running flank 24H of the housing, respectively. If each of the two embodiments is in the same frictional state, the force P can cause the movement Q more easily in the embodiment shown in FIG. 13 than the embodiment shown in FIG. 14. Movement Q is necessary to position the screw back to the center point inside the housing 1. Therefore, as observed in practical experiments, when the running flank is small, the screw 3 is likely to remain in an undesirable position of the housing 1 as shown in FIG. 11 or FIG. 12. In the undesired position as shown in FIGS. 11 and 12, the running flank of the thread on the screw is in line or point contact with the running flank of the thread of the housing and is continuously " face-to-face " Face "contact, i.e. boundary lubrication, cannot occur, resulting in a correspondingly high frictional resistance, which in most cases impedes" charge "movement. It is common practice to lubricate threads with pressurized oil from the engine's lubrication system, but under the aforementioned point or line contact conditions, the desired continuous film lubrication cannot be maintained, so the friction is excessive and the "charge" You will be disturbed or at best sluggish.

In contrast, as shown in FIG. 9, if the valve opening force simultaneously involves the fastening flank 25S of the thread on the screw and the fastening flank 25H of the thread of the housing, the angle of the fastening flank is centered on the screw in the housing. Preferred for positioning. Then there is a continuous oil lubrication state and the fastening flanks connected by the movement of the screw 3 into the housing 1 (named the "back off" movement) destroy the oil film and the metal-to-metal While generating contact, it can be instantaneously generated until the compressive force is activated.

In summary, despite the theoretical high friction / low friction properties of each of the fastening flanks / driving flanks, the "withdrawal" movement can occur very high and / or the "charge" movement can occur very low. If the "retract" movement exceeds the "charge" movement in each valve closing / valve opening cycle, the screw 3 retracts into the housing 1 and the contact between the members of the valve train mechanism is lost.

Not only is it less efficient, but as described, there are manufacturing difficulties, and there are problems with durability when a buttress-type thread is used. This problem is described below.

The aforementioned axial gaps (26 in FIG. 8 and 9 in FIG. 9) should be kept within access limits by proximity control in the manufacture of the inner and outer threads. If the gap is too large, the valve operation will be unsatisfactory and will be noisy. 8 and 9 15, the characteristic values of G _L and G _R are 75 ° and 15 °, respectively. If the symbol C is given to the radial gap (KM in Fig. 15), the axial gap is

JK + KL = (C × tangent 15) + (C × tangent 75)

That is, four times C. For example, this requires a tolerance of 0.1 mm on the axial gap to be set to about 0.05 mm as the diameter tolerance coupled on the inner and outer threads. In mass production, this is a very demanding requirement.

A similar situation occurs with wear of the thread surface in use. The small increase in radial clearance or surface roughness on the inclined flank due to surface wear causes the fourth layer to be added to the axial clearance and also results in unsatisfactory and noisy valve operation.

Techniques for giving grooves or ridges on the screw's fastening flanks are described in GB-2211263. This modification in design was introduced in experiments to maintain the "withdrawal" movement within acceptable limits; Ridges with a reduced surface easily break the oil film between the connecting fastening flanks, and thus result in a faster metal-to-metal state, reducing the sum of the "retract" motions. This design has the following disadvantages.

a. It is difficult to manufacture fastening flanks with grooves or ridges.

b. Since the contact area is reduced, the rate at which wear occurs on the connected fastening flanks increases with increasing axial gap as described in the preceding paragraph.

Close diameter tolerances on the threads of the adjuster's components (ie on the screws or inside the housing) require a closer gap in the manufacture of the tools used in the manufacture of the components. In addition, the ratio of the subwall cross section requires that the teeth of the tab are abnormally wide, which leads to undesirable high tapping torques.

In order to increase the efficiency of an engine with an automatic valve clearance adjuster, the focus is on reducing friction between the cam 10 and the surface contact of the cam follower 8.

The object of the present invention

a. Improve the reliability of the "charge" movement;

b. Reduce friction between the cam and cam follower;

c. Radial gaps / which occur between the inner and outer mating threads when the thread has a buttress type configuration, thus requiring very precise fabrication tolerances and causing a rapid increase in the axial gap between the complementary threads. To avoid undesirable ratio of axial gap

It is to provide an improved structure of the mechanical valve regulator adjuster.

According to an aspect of the present invention, a valve clearance adjuster includes a screw member having an inner threaded housing and an outer thread in the housing, the outer thread having a shape complementary to the inner threaded shape of the housing and fitted into a predetermined axial gap. To; The threads are trapezoidal in shape, symmetrical in axial cross section, and exhibit the same frictional resistance to movement in the axial direction; The flank angle, the thread angle, and the number of screw threads at the start are determined to ensure that the screw member rotates and advances axially from the housing only under the influence of the axial force on the undisclosed end; The exposed end of the screw member is configured to operate in conjunction with, for example, adjacent components of a valve train of an internal combustion engine engine and to receive frictional resistance to rotation from the adjacent components; The bare end of the screw is configured to assist the axial movement of the screw member when it is actuated by the aforementioned axial force.

One reason for slowing down the "charge" movement is that the screw 3 tends to move in a non-concentric position with the housing 1 as shown in FIGS. In the present invention, this tendency is reduced by increasing the angle G _R of the inclination of the traveling flank as already described above with reference to FIGS. 13 and 14.

In order to eliminate the need for very small tolerances on the diameter of the screw thread, it is highly desirable to influence the substantial reduction in the following proportions as already described with reference to FIG. 15.

Axial Clearance ÷ Radial Clearance = tangent G _L + tangent G _R

As an example, by increasing G _R from 15 ° to 30 ° and decreasing G _L from G _L = 75 ° to 30 ° considered as an example, the ratio of axial gap ÷ radial gap (tangent 15 ° + tangent 75 °) to (2 × tangent 30 °), ie from 4 to 1.15.

Thus, in the present invention, the flank of each thread on the screw member and in the housing is preferably inclined at an angle of about 30 ° on each side perpendicular to the axis of the screw thread when viewed in the axial cross section. These flank angles can be found in modern threads, such as those used for standard bolts and nuts, and are typically 60 ° threads. It is commonly used for inspection purposes, for example, fine hardness lines, thread measuring needles, thread making machines, gap gauges and optical projection screens.

The angle G _R of the running flank is equal to the angle G _L of the fastening flank, ie G = G _R = G _L = 30 °. With the thread angle at Z and the friction coefficient at μ, the screw rotating and advancing with the axial load given is expressed by the following equation.

tangent Z> μ ÷ cosine G

This assumes negligible friction on the end of the screw at which the end receives the axial force. As an approximation, a screw with an outer diameter of 8 mm and a lead of 4 mm can rotate and advance under axial loads if the coefficient of friction is less than about 0.14.Increasing the lead to 5 mm is satisfactory at high coefficients of friction, ie 0.17. You can expect it to work. The design of screw threads according to this embodiment can achieve satisfactory results by using two-start threads.

Thus, it is possible to achieve a screw member having a symmetrical thread having a flank angle of 30 ° and advancing while rotating axially by an axial force. In addition, a flank angle of 30 ° allows the screw member to remain concentric with the housing and avoids the point contact state that occurs when a low flank angle is used as described above. The "charge" movement is achieved by the influence of the axial force. This axial force is provided for example by means of hydraulic pressure from the lubrication system of the engine or by small spring means acting on the end of the screw via a ball-end plunger.

In practical experiments, if the screw member is of symmetrical configuration in the form of a "V", the screw member is subjected to a "retract" motion by providing an external friction torque resistance at the end of the screw that is in contact with the end of simultaneous operation of the engine valve train. You can get enough resistance.

According to the design of the engine valve train, the contact area between the end of the screw member and the synchronous actuation member of the valve train may be of the form, for example.

a. Circular line

b. Annular sphere

c. Curved surface area of thin cone

d. Curved surface area of thin spherical slices

For b, c or d, the width is small enough to justify the contact state to assume a line of circular contact. In all cases, the axis of the circle perpendicular to the plane coincides with the axis through which the screw member can rotate. In each of the four cases, the value D can be determined to represent the diameter of the circle on which the frictional resistance acts vertically. Given the average diameter of the screw threads with the sign d, the external frictional resistance to the "retract" motion is usually determined by the ratio of D ÷ d and is therefore controlled according to the design below.

I. Average Diameter of Screws

II. Valve operating end of the screw member

III. Part of the member of the valve train where the part contacts the screw member

As an example, engine test results showed that proper control of the "retract" movement of the regulator was achieved when used in conjunction with a screw thread having a ratio of D ÷ d = 2 with a thread angle of 10 °.

The mode of operation of the regulator according to the invention is shown by way of example corresponding to FIG. 1; 6, 6A; Reference will be made to 7,7A. 5 shows the screw member 3 in an conceptual position in the housing 1 when the gap between the members of the engine valve train becomes large. For convenience of explanation, the total amount of the gap is shown as a single gap 42 between the end 7 of the screw member 3 and the cavity 9 of the cam follower 8. In this situation, the cam 10 may be located at a position where the contact radius thereof contacts the cam follower 8, which is shown in the diagram in FIG. 5A. Because of the relatively high thread angle and the low frictional torque resistance between the ball 29 and the spherical omnipotent portion of the end 6 of the screw member, the spring 22 is "charged" in motion, i.e. as shown in FIG. The screw member 3 can be advanced (shown upwards) from the housing 1 until the surface of the cavity 9 of the follower 8 is in contact with the spherical end 7.

With regard to the situation presented in Figure 6, three things should be observed:

a) The cam 10 may be considered to be disposed at any angular position where a point on a constant radius portion is in contact with the cam follower 8, as schematically shown in FIG. 6A.

b) The gap of the gap is maintained (as described) under the thread of the screw member 3 as in the case of the situation shown in FIG.

c) The force exerted by the spherical end 7 on the surface of the cavity 9 of the cam follower 8 is small. The force is limited to the force of the spring 22 except for the action force necessary to generate the "charge" motion.

7 and 7A illustrate the situation where the cam 10 is rotated to a position where the cam pushes the cam follower 8 sufficiently to move the screw member 3 downward through the existing gap gap 43. present. In other words, the gap of the gap is present above the thread of the screw member 3 (as shown at 44). At this moment, between adjacent threads, a continuous oil film is formed, as a result of which there will be a low resistance to the upward "retract" movement of the screw member from inside the housing 1. Thus, resistance to "retract" movement is provided on the outside by friction in contact between the end 7 of the screw member and the surface of the cavity 9 of the cam follower 8.

Subsequent slight rotation of the cam 10 causes a rapidly increasing load over the entire valve train so that the engine valve overcomes the force held against its seat. The oil film between adjacent threads is broken and friction in the threads contributes to internal resistance to "retraction" movement.

Given the given thread geometry and frictional conditions, the external resistance to the "withdrawal" motion is largely dependent on the ratio D ÷ d, where

D = effective diameter of the circle in frictional contact between the end 7 of the screw and the surface of the cavity 9 of the cam follower 8,

d = average diameter of screw threads.

Therefore, the necessary resistance to the "withdrawal" movement is

Ⅰ Screw thread (its effective diameter)

II valve actuated end 7 of the screw member 3

It is determined by the design of the part in contact with the end 7 of the screw member 3 of the III valve train member.

The increased resistance of the "retract" movement can also be obtained by the angle W (see Figure 6), that is to say by the angle between the common tangent and the transverse plane of the contact surfaces of the cavity 9 and the spherical end 7.

Further rotation of the cam 10 opens the engine valve and then closes it, thereby returning the valve train to a situation equivalent to that of FIG.

If the automatic valve clearance adjuster according to the invention is not incorporated into the valve actuation mechanism, that is to say not assembled to the engine, so that it is not constrained by the engaging elements in the mechanism, the reversible means may cause the screw member to Move outward to its maximum range. In this situation, the adjuster cannot be assembled to the engine and is shortened by withdrawing the screw member into the housing by mutual rotational movement until the overall length of the adjuster is sufficiently reduced so that the adjuster can be placed between the relevant components. Need to lose. In order to assemble a plurality of said regulators in respective positions of respective parts of the valve actuation mechanism for engines having a plurality of valves, means for temporarily holding the regulators in their retracted state to facilitate such assembly are provided. It is preferred to be provided.

It is an object of another aspect of the present invention to meet, in general, the need described above for temporarily holding the regulator in its retracted state.

Therefore, according to another aspect of the invention, a housing having a screw thread therein, a screw member having an outer screw thread extending from the open end into the housing and engaging with the thread in the housing, and its longitudinal axis relative to the screw member; A spring means acting in the direction of; The interaction of the screw thread of the screw member with the housing is such that the screw member rotates forward out of the housing under the action of the spring means; A contact means operable between the screw member and the housing is provided when the screw member is screwed into an inner position into the housing, thereby providing a screw member in the inner position between the screw member, the housing and the contact means. A valve clearance regulator is provided in which a sufficient frictional force can be established to counter against the action of.

In the valve gap regulator according to this aspect of the invention, the screw member can be screwed into its housing in its inner position, in which the actuating contact means is engaged between the screw member and the housing. When the screw member is tightened so that increased force is applied between the screw member, the contact means and the housing, therebetween is sufficient to resist the action of the spring means which tends to advance the screw member out of the housing. Friction force will be established. The size of the valve clearance regulator should be such that when the screw member is in its inner position, the overall length of the regulator is small enough so that it can be easily assembled in the required position of the actuation mechanism for the valve of the engine; Thus, an engine having a plurality of valve gap regulators can be easily assembled. According to the test, when the engine is started, the impact caused by each regulator by a collision from a cam actuating a particular valve is sufficient to release the friction between the screw and the housing, so that the screw member It shows that the correct operating position can be taken.

The screw member of the adjuster is adapted to be engaged by a tool so that it is screwed into the housing so that the contact means is operated as above. In an embodiment of the adjuster described below, the screw member has a head having a partially spherical surface that engages a complementary partially spherical socket, such as a rocker arm, wherein the tool that engages the screw member has a screw inward position. And a socket or recess having a surface shape capable of establishing a frictional engagement with the head of the screw member sufficient to be able to tighten the screw member to engage the contact means when in the position of the screw member.

The contact means includes a shoulder structure that is provided inside the housing and that can engage the innermost end surface of the screw member when the screw member is in its inner position. Such a shoulder may be provided by the housing itself, or an independent member such as a sleeve providing such a shoulder may be inserted into the housing.

Alternatively, the screw member can have a contact structure that can engage the end face of the housing. Such a structure may comprise a collar provided on a screw member below its head portion. Such a collar can also be used to tighten the screw member when the collar engages the housing by holding the screw member in the housing, thereby eliminating the need for a separate tool used in such cases.

Preferably, the valve gap regulator is in accordance with the first aspect of the present invention. However, it could alternatively be a regulator comprising buttress threads such as those mentioned in the prior art description.

Figure 16 presents a regulator such as that shown in Figure 5, Figure 6 or Figure 7 in a state that can be taken if it is not assembled to the engine. As the screw member advances out of the housing, the overall length of the regulator will be substantially larger than the space available to be occupied by the regulator in the engine.

Therefore, in order to assemble the regulator in the engine, the screw member 3 must be screwed into the housing 1 to the extent that the overall length of the regulator is reduced to such an extent that it can enable easy assembly. The overall length of such regulators will be slightly shorter than the typical operating length of the regulators shown in FIGS. 6 and 7.

If the characteristics of the screw thread operating between the screw member and the housing of the adjuster cannot hold the screw member in this position by friction, according to the invention, the screw member is placed in the innermost position similar to that shown in FIG. A contact means operable between the screw member and the housing can be provided when present. One form of such contact means is shown in FIG. 17, which is provided by a cylindrical sleeve 50 disposed in the housing and surrounding the spring 22. One end of the sleeve 50 engages the closed lower end 51 of the housing, the other end of the sleeve abuts the end face 6 of the screw member in an annular area surrounding the recess.

When the screw member is screwed into the housing and tightened to engage the contact sleeve 50, a force is established between the screw member and the sleeve, and between the thread and the interacting thread of the screw member, by means of the spring 22. In spite of the applied force, it allows the screw member to be frictionally held in its innermost position. This allows the regulator to be easily installed. However, when the engine on which the regulator is installed is started, the impact by the cam is sufficient to release the friction between the screw member and the housing, so that the screw immediately occupies the correct operating position as disclosed above.

In place of the sleeve 50, the housing may have an integral contact structure that can engage when the screw member is in its innermost position. Such a structure can be provided, for example, by having the interior of a smaller diameter housing in the portion occupied by the spring 22, below the lower end of its inner screw thread. The screw member may also have an outer collar that can engage the outer end face 55 of the housing below the head. Such a collar can be used as a means for rotating the screw when the screw is screwed into the housing until the collar is in contact with the housing.

If the screw member does not have the collar or other structure that allows it to be screwed into the housing in the same manner as above, a tool such as indicated by reference numeral 52 in FIG. It can engage with the end 7 of the spherical head and rotate it. The tool 52 has a tapered socket 53 at one end, the angle of which is brought into the housing against the action of the spring 22 when it is pressed by hand to engage the head of the screw member. The screw member may be frictionally grasped with a force sufficient to be screwed into engagement with the contact sleeve 50. The tool 52 has a gripping portion 54 that allows the person using it to easily grasp and rotate it.

As described above, in some designs of regulators that incorporate spring means for axially advancing the screw member out of the housing, the aforementioned means may not need to facilitate assembly of the regulator in the engine. As described above, the test of the engine, in conjunction with a screw thread with a 10 ° helix angle, provides proper control of the regulator "retract" movement, providing a reliable and responsive "charge" movement of the regulator. It is suggested that the ratio / d is used when used. However, if the overall engine design consideration imposes a restriction that requires a lower D / d value, the lower thread helix angle should be considered. For example, a regulator that must have a helix angle of 6 °, in order to generate an appropriate "charge" motion when effectively lubricated in the engine, should have sufficient threads to hold the screw in an internal position within the housing without the need for an assembly device. Should have friction.

In the present specification, "comprising" means "consisting of or consisting of" and "comprising" means "consisting of or of being composed of.

The features disclosed in the above specification, or the claims set forth below, or in the appended drawings, or methods or processes for carrying out the disclosed results, expressed in a specific form or means for carrying out the functions disclosed above, or Combinations of features can be used to practice the invention in various forms.

Claims (23)

A screw-threaded housing 1 inside; A screw-threaded screw member 3 extending outwardly in the housing, the screw thread 4 of the screw member 3 being a complementary and predetermined axis to the thread form of the inner thread 2 of the housing. Has an contour that fits into the directional gap, the thread is trapezoidal in shape, symmetrical in axial cross section, and exhibits the same frictional resistance to axial movement; The flank angle, the spiral angle, and the number of screw threads at the start are determined in the housing to ensure that the screw member rotates and advances axially from the housing only under the influence of the axial force on its end; The exposed end (7) of the screw member is characterized in that it is adapted to operate to accommodate frictional resistance to rotation with respect to adjacent components. 2. The automatic valve gap adjuster of claim 1, wherein the flank of each thread in the screw member and the housing is inclined at an angle of 30 [deg.] With respect to the vertical axis of the screw thread. 3. The boosting end of the screw member according to claim 1 or 2, (a) circular lines (b) annular regions (c) curved surface area of the thin cone (d) curved surface area of thin spherical slices Wherein the regulator is adapted to be in contact in one of the two. 4. The regulator of claim 3, wherein in contact with said adjacent component at b, c or d, the contact area is close to line contact. 5. The regulator of claim 3 or 4, wherein the diameter of the contact line or region is greater than the average diameter of the screw threads of the regulator. 6. The adjuster of any one of claims 1 to 5, comprising spring means acting on the screw member to axially advance the screw member away from the housing. 7. The adjuster of claim 6, wherein the spring means acts on the end of the screw member through a ball-end member in the housing. 6. The adjuster of any one of claims 1 to 5, wherein the screw member is adapted to act by hydraulic pressure to force it out of the housing in the axial direction. The method of claim 6 or 7, wherein a contact means operable between the screw member and the housing is provided when the screw member is screwed into an inward position into the housing, thereby providing a connection between the screw member, the housing and the contact means. And a friction force sufficient to hold the screw member in the inner position against the action of the spring means can be established. A housing having a screw thread therein, a screw member having an outer screw thread extending from the open end into the housing and engaged with the thread in the housing, and spring means acting in the direction of its longitudinal axis relative to the screw member; Configured; The interaction of the screw thread of the screw member with the housing is such that the screw member rotates forward out of the housing under the action of the spring means; A contact means operable between the screw member and the housing is provided when the screw member is screwed into an inner position into the housing, thereby providing a screw member in the inner position between the screw member, the housing and the contact means. A valve clearance regulator in which sufficient frictional force can be established to hold against the action of. 11. The adjuster of claim 9 or 10, wherein the contact means includes a shoulder structure that is engageable by the innermost end surface of the screw member inside the housing. 12. The regulator of claim 11, wherein said shoulder is provided by said housing. 12. The regulator of claim 11, wherein said shoulder is provided by a member disposed within said housing. 11. The adjuster of claim 9 or 10, wherein the screw member has a contact structure that can engage the end face of the housing. The adjuster of claim 14, wherein the structure comprises a collar provided on the screw member below the head portion. 16. The adjuster of claim 15 wherein the collar retains the screw member to screw the screw member into the housing. 17. A screw according to any one of claims 9 to 16, characterized in that the screw member is adapted to be engaged by a tool for screwing the screw member into the housing so that the contact means is actuated. Regulator. A combination according to claim 17 and the tool engageable with the adjuster. 19. The combination as set forth in claim 18, wherein said tool is in frictional engagement with said head portion of said screw member. A valve actuation mechanism comprising an automatic valve clearance adjuster according to any one of claims 1 to 17 arranged between each component of the mechanism to take a gap between the components. An internal combustion engine comprising a plurality of valve actuation mechanisms according to claim 20. An automatic valve gap regulator substantially disclosed herein with reference to FIGS. 5-7 or 17 of the accompanying drawings. Novel features disclosed in the specification and / or accompanying drawings, or novel combinations of the features.