DE112009000693T5 - Lash adjuster - Google Patents

Abstract

A clearance compensation device comprising a cylindrical housing (13) having a bottom (17) and received in a mounting hole (6) formed in an upper surface of a cylinder head (2), said housing (13) having an internal thread (14 ), an adjusting screw (16) having an external thread (15) on an outer periphery thereof threadedly coupled to the internal thread (14) of the housing (13), and a return spring (18) between the adjusting screw (16) and the bottom (17) of the housing (13) and biasing the adjusting screw (16) in a direction to project upwardly from the housing (13), the adjusting screw (16) being a protruding one End (22) projecting from the housing (13) and adapted to rotatably support an arm (7) of a valvetrain, characterized in that the play compensating device further comprises a rotation preventing device for preventing r rotation of the housing (13) contains.

Description

Technical area

This invention relates to a lash adjuster mounted in a valve train of an engine.

Technical background

A known valvetrain for moving the valve at an intake or exhaust port of an engine includes an arm which is pivotal about one of its ends and adapted to be pushed down at its central portion by a cam, thereby displacing the valve stem at its other end pushes down.

In this valvetrain, gaps between the components of the valvetrain tend to change during operation of the engine due to differences in thermal expansion between the components of the valvetrain, which may result in noise or compression loss. As sliding parts of the valve train also wear, gaps between the components of the valve train change resulting in noise or compression loss.

To prevent such noise and compression loss, a typical valvetrain includes a lash adjuster to eliminate gaps between components of the valvetrain.

Typically, such a lash adjuster includes a cylindrical housing having a bottom and received in a mounting hole formed in the top surface of the cylinder head, an adjustment screw having an external thread on its outer circumference threadedly coupled to an inner one Inner circumference of the housing formed and a return spring comprises, which biases the adjusting screw in the direction that it protrudes from the housing upwardly, whereby the arm of the valve train by the end of the protruding from the housing adjusting screw is rotatably supported (Patent Documents 1 and 2)

In the arrangement of Patent Document 1, the return spring is a compression coil spring that exerts an axial force on the adjustment screw, which seeks to push the adjustment screw out of the housing. In the arrangement of Patent Document 2, the return spring is a torsion spring that applies a torque to the adjusting screw, which seeks to push the adjusting screw out of the housing.

In these lash adjusters, as the cam rotates and acts on the adjustment screw, a force tending to urge the adjustment screw is borne by the external thread of the adjustment screw through the internal thread of the housing such that the adjustment screw is axially retained in position.

• Patentdokument 1: JP Patentveröffentlichung 2005-273510A
• Patentdokument 2: JP-Patentveröffentlichung 64-34407A

When the relative position of the arm and the cylinder head z. B. changed due to thermal expansion of the valve train, the adjusting screw moves axially in the housing according to the extent of the change in the relative position while it rotates relative to the housing, and thus absorbs the changes of gaps between components of the valve train.

• Patent Document 1: JP Patent Publication 2005-273510A
• Patent Document 2: Japanese Patent Publication 64-34407A

Disclosure of the invention

Object of the invention

In these lash adjusters, since the outer circumference of the housing and the inner circumference of the mounting hole are both cylindrical surfaces, when a force is applied to the housing in the rotational direction, the housing moves relative to the mounting hole. In particular, when the engine is running and the temperature of the valvetrain is high, the housing tends to move slightly relative to the housing, because in this state, due to the difference in thermal expansion between the cylinder head and the housing, there is a gap between mounting surfaces of the housing and forms the mounting hole.

Thus, in these lash adjusters, as the cam rotates and a force acts on the adjustment screw that seeks to force the adjustment screw in, the housing moves relative to the mounting hole by the force acting between the threaded surfaces of the adjustment screw and the housing. As the housing rotates, the adjustment screw is forced into the housing, reducing the valve lift. By rotation of the housing and the wear of the mounting hole would accelerate.

An object of the present invention is to prevent rotation of the housing when a force acts on the adjusting screw, which seeks to push in the adjusting screw.

Means of accomplishing the task

In order to achieve this goal, a rotation Preventing device for preventing the rotation of the housing provided.

The rotation preventing device may include a rotation preventing projection provided on the bottom of the housing, and a fixing hole formed in an inner bottom surface of the mounting hole in which the rotation preventing projection is fixed. With this arrangement, the housing is prevented from rotating because the rotation prevention projection engages with the attachment opening.

The rotation preventing projection may be a projection having a D-cut portion on its outer circumference, a projection having two bevels on its outer circumference, a protrusion in the shape of a regular polygonal pillar, or a projection offset from an axis of the housing.

The attachment opening may be a side of a vent hole that extends outwardly from the inner bottom surface of the mounting hole. With this arrangement, when the lash adjuster is inserted into the mounting hole, air is discharged between the bottom of the housing and the inner bottom surface of the mounting hole through the vent hole, so that the inside of the mounting hole is kept at atmospheric pressure, which prevents a counterforce on the Bottom of the housing acts. Thus, the lash adjuster can be easily mounted in the cylinder head. Since one side of the ventilation opening is used as the attachment opening, it is not necessary to form the attachment opening separately from the ventilation opening, which makes the formation of the cylinder head easier.

A through hole may be formed to extend vertically through the bottom of the housing with a lower end thereof open to a free end of the rotation prevention protrusion. With this arrangement, since engine oil flowing into the case between the external thread of the adjusting screw and the female thread of the case flows through the through hole and then the vent hole, it is less likely that soot and other contaminants mixed in the engine oil will be between the male threads of the engine oil Stick the adjusting screw and the internal thread of the housing, making it less likely that the external thread and the internal thread wear out.

The rotation preventing device may be a friction ensuring device for ensuring the frictional resistance between the bottom of the housing and the inner surface of the mounting hole, thereby preventing the rotation of the housing.

The friction ensuring device includes an oil film-driving groove formed in an outer bottom surface of the housing. With this arrangement, engine oil existing between the outer bottom surface of the housing and the inner bottom surface of the mounting hole is discharged into the oil film-driving grooves. Thereby, the formation of an oil film between the outer bottom surface of the housing and the inner bottom surface of the mounting hole is prevented because of the displacement effect, which in turn ensures a sufficient frictional resistance between the outer bottom surface of the housing and the inner bottom surface of the mounting hole.

The friction ensuring means may comprise a frosted surface formed on the outer bottom surface of the housing. With this arrangement, as compared with an arrangement in which the outer bottom surface of the housing is flat and smooth, the outer bottom surface of the housing has a larger friction coefficient, so that it is possible to provide sufficient frictional resistance between the outer bottom surface of the housing and the inner bottom surface of the mounting hole. The outer bottom surface of the housing may be satinized by electrical discharge machining or laser machining. Preferably, however, it is satinized by shot peening, as by shot peening the outer bottom surface of the housing is hardened, whereby their wear resistance is increased.

The friction ensuring means may comprise a conical outer peripheral surface formed on the bottom of the housing and having a downwardly decreasing diameter, and a conical inner peripheral surface formed on the mounting hole and having a downwardly decreasing diameter the conical outer edge surface engages the conical inner edge surface. With this arrangement, the wedge effect creates a high surface pressure between the conical outer peripheral surface and the conical inner peripheral surface which ensures sufficient frictional resistance between the conical outer peripheral surface and the conical inner peripheral surface.

The friction ensuring means may comprise a recess formed in the outer bottom surface of the housing except for its outer edge. With this arrangement, the frictional resistance is concentrated between the outer bottom surface of the housing and the inner bottom surface of the mounting hole the radial outside, so that it is possible to ensure a sufficient frictional resistance for preventing the rotation of the housing. Alternatively, as the friction ensuring device, a similar recess may be formed in the inner bottom surface of the mounting hole except for its edge.

The friction ensuring means may comprise a small-diameter inner peripheral part formed on the mounting hole, the bottom of the case being press-fitted into the small-diameter inner peripheral part. With this arrangement, the pressing creates a high surface pressure between the bottom of the housing and the small diameter inner edge portion which ensures sufficient frictional resistance between the bottom of the housing and the inner surface of the mounting hole.

The friction ensuring means may comprise a plate made of rubber or an elastomer, which is disposed between an outer bottom surface of the housing and the inner bottom surface of the mounting hole. With this arrangement, the frictional resistance between the outer bottom surface of the housing and the inner bottom surface of the mounting hole is greater than when the outer bottom surface of the housing is in direct contact with the inner bottom surface of the mounting hole, so that it is possible to provide a sufficient frictional resistance for preventing the Ensure rotation of the housing.

The friction ensuring device may include a seat made of iron and forming the inner bottom surface of the mounting hole. With this arrangement, since it is less likely that the inner bottom surface of the mounting hole will wear, even if the cylinder head is made of aluminum, it is possible to minimize the reduction of the friction coefficient of the inner bottom surface of the mounting hole with time, thereby providing sufficient frictional resistance between the bottom of the housing and the inner surface of the mounting hole is ensured.

The friction ensuring means may comprise a sleeve made of iron and forming the mounting hole. With this arrangement, since it is less likely that the inner surface of the mounting hole will wear even if the cylinder head is made of aluminum, it is possible to minimize the reduction of the friction coefficient of the inner surface of the mounting hole with time, thereby providing sufficient frictional resistance between the ground the housing and the inner surface of the mounting hole is ensured.

The return spring may be a compression coil spring which exerts an axial force on the adjustment screw which tends to push the adjustment screw out of the housing. Alternatively, the return spring may be a torsion spring which applies a torque to the adjusting screw, which seeks to push the adjusting screw out of the housing. The torsion spring may be one of a torsion coil spring, a coil spring and an evolute spring.

The external thread and the internal thread are pointed threads, trapezoidal threads or sawtooth-shaped threads.

Advantages of the invention

Since a rotation preventing means is provided on the lash adjuster according to this invention to prevent the rotation of the housing, the housing is less likely to rotate when a force is applied to the adjusting screw which seeks to press the adjusting screw. As a result, a reduction of the valve lift is prevented by rotation of the housing. The lash adjuster thus stably performs its function. It is also possible to prevent wear of the inner surface of the mounting hole.

Short description of the drawing

1 FIG. 10 is a front view of a valvetrain incorporating a lash adjuster according to a first embodiment of the present invention. FIG.

2 is an enlarged sectional view of the lash adjuster from 1 and their surroundings.

3 is a sectional view taken along the line III-III of 2 ,

4 is an enlarged view of an out to the 2 distinctive Turn Prevention Tab.

5 is a sectional view taken along the line VV of 4 ,

6 an enlarged view is still one to look at 2 distinctive Turn Prevention Tab.

7 is a sectional view taken along the line VII-VII of 6 ,

8th is an enlarged sectional view of another to that from 2 distinctive Turn Prevention Tab.

9 is a sectional view taken along the line IX-IX of 8th ,

10 FIG. 10 is an enlarged sectional view of a lash adjuster according to a second embodiment of the present invention. FIG.

11 FIG. 10 is an enlarged sectional view of a modification of FIG 10 shown return spring.

12 FIG. 15 is an enlarged sectional view of another modification of FIG 10 shown return spring.

13 is a sectional view taken along the line XIII-XIII of 12 ,

14 FIG. 10 is an enlarged sectional view of still another modification of FIG 10 shown return spring.

15 FIG. 10 is an enlarged sectional view of a lash adjuster according to a third embodiment of the present invention. FIG.

16 is a sectional view taken along the line XVI-XVI of 15 ,

17 FIG. 10 is an enlarged sectional view of a modification of FIG 15 shown friction ensuring device.

18 FIG. 15 is an enlarged sectional view of another modification of FIG 15 shown friction ensuring device.

19 FIG. 10 is an enlarged sectional view of still another modification of FIG 15 shown friction ensuring device.

20 FIG. 15 is an enlarged sectional view of another modification of FIG 15 shown friction ensuring device.

21 FIG. 10 is an enlarged sectional view of still another modification of FIG 15 shown friction ensuring device.

22 FIG. 10 is an enlarged sectional view of still another modification of FIG 15 shown friction ensuring device.

23 FIG. 10 is an enlarged sectional view of still another modification of FIG 15 shown friction ensuring device.

LIST OF REFERENCE NUMBERS

1

Lash adjuster

2

cylinder head

6

mounting hole

7

poor

13

casing

14

inner thread

15

external thread

16

adjustment

17

ground

18

return spring

22

Prominent end

24

Inner floor area

25

vent hole

26

mounting hole

27

Rotation preventing projection

28

D-shaped cut out part

30

Through Hole

31

Two bevels

32, 35, 37

Rotation preventing projection

41, 51

Lash adjuster

52

External floor surface

53

Oil film expelling groove

54

Conical inner edge surface

55

Conical outer edge surface

56

deepening

57

Inner edge part with a small diameter

58

plate

59

Seat

61

shell

Best mode of implementation of the invention

1 shows a valve train having a lash adjuster 1 according to a first embodiment of the present invention. This valve train contains a valve 4 at an intake opening 3 a cylinder head 2 a motor is arranged, a valve stem 5 that with the valve 4 connected, a clearance compensation device 1 placed in one on the upper surface of the cylinder head 2 trained mounting hole 6 is built in, and an arm 7 that by the play compensation device 1 is held so that he is around the lash adjuster 1 is pivotable.

The valve stem 5 extends from the valve 4 upwards and slidably extends through the cylinder head 2 ,

An annular spring plate 8th is on the outer circumference of the valve stem 5 attached to its upper part A valve spring 9 is between the lower surface of the spring plate 8th and the upper surface of the cylinder head 2 assembled. The valve spring 9 sets the valve stem 5 up through the spring plate 8th under tension, thereby setting the valve with its tension 4 on a valve seat 10 ,

The one end of the arm 7 is through the game compensation device 1 supported, and the other end is in contact with the upper end of the valve stem 5 , At its middle area carries the arm 7 a role 11 that with one over the roll 11 provided cam 12 is in contact.

As in 2 includes the lash adjuster 1 a cylindrical housing 13 which has a bottom and in the mounting hole 6 is inserted, an adjustment screw 16 , on its outer edge at its lower part an external thread 15 which has one on the inner edge of the housing 13 trained internal thread is in threaded coupling, and one between the adjusting screw 16 and the floor 17 of the housing 13 assembled return spring 18 ,

The external thread 15 and the internal thread 14 Both have a pressure flank for receiving pressure when the adjusting screw 16 is applied with a force that endeavors the adjusting screw 16 in the case 13 to press. The pressure flank 19 has a larger flank angle than the Hängigkeitsflanke 20 so the threads 15 and 14 have a sawtooth-shaped longitudinal section.

The return spring 18 is a compression coil spring, whose lower end is on the ground 17 of the housing 13 rests and exercises at its upper end over a Federsitz 21 an axial force on the adjusting screw 16 out, which is the adjusting screw 16 upwards out of the case 13 seeks to push.

As in 1 shown points the adjusting screw 16 a projected end 22 on, from the case 13 protrudes and into a depression 23 engages in the lower surface of the arm 7 is formed at its end and thus supports the arm 7 so he's around the protruding end 22 is rotatable. A ventilation hole 25 is in the cylinder head 2 designed to extend from an inner floor surface 24 of the mounting hole 6 to extend to the outside. When the clearance compensation device 1 in the mounting hole 6 is inserted, air is between the housing 13 and the inner floor surface 24 of the mounting hole 6 through the ventilation hole 25 derived.

As in 2 shown is a Turn Prevention Tab 27 on the ground 17 of the housing 13 formed in a mounting hole 26 It is fixed in the inner floor area 24 of the mounting hole 6 is trained. The mounting hole 26 forms one end of the ventilation hole 25 , The Turn Prevention Tab 27 has a D-shaped cut-out part 28 on its outer circumference, in a D-shaped cut out part 29 engages on the inner circumference of the mounting hole 26 is formed, whereby he the housing 13 non-rotatably in position. The D-shaped cut out part 28 is formed by the outer circumference of the projection 27 along a plane parallel to a plane that is the axis of the housing 13 contains, is cut.

The housing 13 is made of iron to increase the strength of the internal thread 14 sure. The mounting hole 26 holding the D-shaped cut out part 29 on its inner circumference, and the ventilation hole 25 that the mounting hole 26 has at one end, can be formed when the cylinder head 2 is formed by die-casting of aluminum.

As in 2 shown, a through hole extends 30 vertically through the ground 17 of the housing 13 with its bottom to the lower end surface of the rotation-preventing projection 27 is open. Thus, engine oil is removed from the upper surface of the housing 13 through the gap between the external thread 15 and the internal thread 14 in the case 13 flows, from the housing 13 through the through hole 30 and then the ventilation hole 25 derived.

Now, the operation of the lash adjuster 1 described.

While the engine is running when the cam 12 turns and the cam hump 12a of the cam 12 the arm 7 presses, the valve separates 4 from the valve seat 10 and opens the suction opening 3 , At this time, a force is applied to the adjusting screw 16 applied, which seeks to press in the adjusting screw. But because in this state, the pressure flank 19 of external thread 15 through the pressure flank 19 of the internal thread 14 is worn, the adjusting screw 16 held axially in position. Also, a torque between the pressure edges 19 of external thread 15 and the internal thread 14 created. Because of the coupling between the rotation prevention projection 27 and the attachment opening 26 the housing rotates 13 but never.

When the cam 12 continues to turn and the Nockenbuckel 12a behind the role 11 moves, raises the valve stem 5 under the biasing force of the valve spring 9 so that the valve 4 on the valve seat 10 sits and the intake 3 closes.

In fact, when the arm occurs 7 through the cam hump 12a of the cam 12 is pressed down, a slight glide between the pressure flanks 19 of external thread 15 and the internal thread 14 on, leaving the adjusting screw 16 is pressed into it. But as soon as the Nockenbuckel 12a behind the role 11 moved, and the force is removed, which endeavors to press in the adjusting screw, the adjusting screw returns 16 under the force of the return spring 18 , which tries to push out the adjusting screw, back to the initial position.

If, while the engine is running, the distance between the cam 12 and the arm 7 due to differences in thermal expansion between the components of the valvetrain, including the cylinder head 2 , the valve stem 5 and the arm 7 , increased, enters the adjustment screw 16 by a longer distance out when the cam 12 continues to turn after the arm 7 through the cam hump 12a of the cam 12 is depressed until the force is released, as the distance to which the adjusting screw 16 is pushed in when the arm 7 through the cam hump 12a of the cam 12 is pressed down. As a result, the adjustment screw moves 16 every time the cam 12 Once it rotates, gradually forward, causing each gap between the base circle 12a of the cam 12 and the role 11 eliminated.

Conversely, when the contact surfaces of the valve 4 and the valve seat 10 Wear, the biasing force of the valve spring acts 9 continue on the adjusting screw 16 even during the base circle 12b of the cam 12 the role 11 faces. Thus, the adjusting screw moves 16 by a shorter distance before, when the cam 12 continues to turn after the arm 7 through the cam hump 12a of the cam 12 is depressed until the force is released, as the distance to which the adjusting screw 16 is pushed in when the arm 7 through the cam hump 12a of the cam 12 is pressed down. As a result, every time the cam is turned on 12 once turns, the adjusting screw 16 gradually pushed in what it did to the valve stem 5 allowed to rise gradually. This prevents the formation of a gap between the contact surfaces of the valve 4 and the valve seat 10 ,

With this clearance compensation device 1 the housing rotates 13 never when a force is applied to the adjusting screw 16 is applied, which seeks to squeeze the adjusting screw, as the housing 13 rotationally fixed in position between the rotation prevention projection 27 and the attachment opening 26 is attached. This results in a reduction of the valve lift by rotation of the housing 13 prevented. The lash adjuster thus stably performs its function. Also wears the inner surface of the mounting hole 6 never.

With this clearance compensation device 1 when the play compensation device 1 in the mounting hole 6 is inserted, air between the ground 17 of the housing 13 and the inner floor surface 24 of the mounting hole 6 through the ventilation hole 25 derived, leaving the interior of the mounting hole 6 is kept at atmospheric pressure, which prevents a drag on the ground 17 of the housing acts. Thus, the lash adjuster can easily in the cylinder head 2 to be assembled. As one side of the ventilation opening 25 as a mounting hole 26 is used, it is not necessary, the mounting hole 26 separated from the ventilation opening 25 form what the forming of the cylinder head 2 makes it easier.

With this clearance compensation device 1 It is because engine oil is between the external thread 15 the adjusting screw 16 and the internal thread 14 of the housing 13 flows into the housing, through the through hole 30 and then the ventilation hole 25 it is less likely that the soot and other contaminants mixed into the engine oil will drain between the external threads 15 the adjusting screw 16 and the internal thread 14 of the housing 13 stick, making it less likely that the external thread 15 and the internal thread 14 wear out.

In this embodiment, it is on the ground 17 of the housing 13 provided rotation prevention projection 27 the Turn Prevention Tab 27 that the D-shaped cut out part 28 on the outer circumference. Instead of this Turn Prevention Tab 27 But, as in the 4 and 5 shown a rotation prevention tab 32 to be used, the two bevels 31 having. By the two bevels 31 in the two bevels 34 grip on the inner circumference of the mounting hole 33 are formed, it is possible to rotate the housing 13 to prevent. With this arrangement, the rotation prevention protrusion 32 in the mounting hole 33 be fastened, even if the housing 13 rotated 180 °, the lash adjuster can 1 lighter in the cylinder head 2 to be assembled. The two bevels 31 are two flat surfaces that are parallel to a plane that is the axis of the housing 13 contains.

Instead of Turn Prevention Tab 27 can also, as in the 6 and 7 shown a rotation prevention tab 35 in the form of a regular polygonal column (such as a regular hexagonal column) 35 to be used. By doing this Turn Prevention Tab 35 in a mounting hole 36 In the form of a regular polygonal column attacks, it is possible a rotation of the housing 13 to prevent. With this arrangement, the rotation prevention tab can 35 in the mounting hole 36 in a variety of different angular positions of the housing 13 be secured, the play compensation device 1 can continue easily in the cylinder head 2 to be assembled.

As in the 8th and 9 The Turn Prevention Tab can be shown 27 also by a turn prevention tab 37 be replaced by the axis of the housing 13 is offset. This Turn Prevention Tab 37 is in a mounting hole 38 coupled by the axis of the mounting hole 6 is offset to a rotation of the housing 13 to prevent.

10 shows a lash adjuster 41 according to the second embodiment of the present invention. Like the Turn Prevention Tab 27 on the ground 17 of the housing 13 contains this clearance compensation device 41 same spin prevention tab 27 as in the first embodiment, ie, the, the D-shaped cut-out part 28 on the outer circumference. Below-mentioned elements corresponding to those of the first embodiment are denoted by identical reference numerals, and their description is omitted.

The adjusting screw 16 includes an axially displaceable in the housing 13 inserted rotary element 16A , an externally threaded element 16B which is the end of the case 13 used rotary element 16A supports and an external thread 15 has at its outer periphery, and a spring washer 16C that is between the rotary element 16A and the externally threaded member 16B is arranged.

The return spring 18 is a torsion coil spring, whose lower end with a receiving hole 42 coupled in the ground 17 of the housing 13 is formed, and the upper end with a receiving hole 43 coupled in the externally threaded member 16B is trained. Because of their torsional deformation exerts the return spring 18 a torque on the externally threaded element 16B in the direction of that the rotary element 16A out of the case 13 is pressed.

On the ground 17 of the housing 13 is the rotation prevention projection 27 that the D-shaped cut out part 28 on the outer circumference. The Turn Prevention Tab 27 is in the mounting hole 26 coupled in the inner floor area 24 of the mounting hole 6 is trained.

With this clearance compensation device can, as with the first embodiment, since the rotation of the housing 13 by the engagement of the rotation prevention projection 27 in the mounting hole 26 prevents a reduction of the valve lift by rotation of the housing 13 be prevented, so that the lash adjuster can perform their function stably.

With this clearance compensation device 41 is when the engine is switched off at a high temperature and the engine cools, causing differences in the contraction of the components of the valve lever, the spring washer 16C between the externally threaded element 16B and the rotary element 16A compressed, thereby absorbing the differences in contraction. Thus, when the engine is restarted, between the valve 4 and the valve seat 10 no gap is caused due to differences in the thermal expansion between the components of the valve lever, whereby compression loss is prevented.

When the return spring 18 is a torsion coil spring, the return spring 18 a cylindrically wound, as in 10 shown, or a conically wound, as in 11 shown.

As in the 12 to 14 shown, the return spring 18 unlike a torsion coil spring, be a torsion spring.

The in the 12 and 13 shown return spring 18 is an evolute spring formed by helically winding a thin sheet material. The radial outer end of this return spring 18 is rotatable on the ground 17 of the housing 13 fastened, and its radial inner end is fastened in a slot, which in a projection 44 at the end of the externally threaded element 16B is trained, that in the case 13 is used. Because of their torsional deformation exerts the return spring 18 a torque on the externally threaded element 16B in the direction of that the rotary element 16A out of the case 13 is pressed. The external thread 15 on the outer periphery of the externally threaded member 16B and the internal thread 14 on the inner circumference of the housing 13 are vertically symmetrical trapezoidal threads.

In the 14 shown return spring 18 is a helical spring formed by helically winding a thin sheet material. The radial outer end of this return spring 18 is rotatable on the ground 17 of the housing 13 fastened, and its radial inner end is fastened in a slot, which in a projection 45 at the end of the externally threaded element 165 is formed in the housing 13 is used. Because of their torsional deformation exerts the return spring 18 a torque on the externally threaded element 16B in the direction of that the rotary element 16A out of the case 13 is pressed. The external thread 15 on the outer periphery of the externally threaded member 165 and the internal thread 14 on the inner circumference of the housing 13 are vertically symmetrical pointed threads.

In the above embodiments, the floor may 17 of the housing 13 be integral with the housing body, as shown. But the ground 17 of the housing 13 may be formed separately from the housing body and attached to the bottom of the housing body.

The 15 and 16 show a clearance compensation device 51 according to the third embodiment of the present invention.

In this embodiment, the outer bottom surface is 52 of the housing 13 in contact with the inner bottom surface 24 of the mounting hole 6 so that an axial force is carried on the housing 13 on the inner floor surface 24 of the mounting hole 6 is applied. A variety of linear oil film expelling grooves 53 is on the outer floor surface 52 of the housing 13 educated.

With this clearance compensation device 51 is, although a torque between the pressure flanks 19 of external thread 15 and the internal thread 14 is generated when a force is applied to the adjusting screw 16 is applied, which seeks to push the adjusting screw, by the frictional resistance between the outer bottom surface 52 of the housing 13 and the inner floor surface 24 of the mounting hole 6 the rotation of the housing 13 prevented.

If through the arm 7 a force on the adjusting screw 16 is applied, which seeks to squeeze the adjusting screw, engine oil, which is between the outer bottom surface 52 of the housing 13 and the inner floor surface 24 of the mounting hole 6 is present in the oil film expelling grooves 53 issued. As a result, the formation of an oil film between the outer bottom surface 52 of the housing 13 and the inner floor surface 24 of the mounting hole 6 prevented due to the displacement effect, in turn, a sufficient frictional resistance between the outer bottom surface 52 and the inner floor surface 24 ensures.

In this embodiment, in order to have a sufficient frictional resistance between the ground 17 of the housing 13 and the inner surface of the mounting hole 6 to ensure the oil film expelling grooves 53 in the outer bottom surface 52 of the housing 13 educated. As in 17 but may instead show the outer bottom surface 52 of the housing 13 be satined. With this arrangement has compared to an arrangement in which the outer bottom surface 52 even and smooth, the outer bottom surface 52 a larger coefficient of friction, so that it is possible to have a sufficient frictional resistance between the outer bottom surface 52 and the inner floor surface 24 sure.

If through the arm 7 a force on the adjusting screw 16 is applied, which seeks to squeeze the adjusting screw, engine oil, which is between the outer bottom surface 52 and the inner floor surface 24 is present, discharged into the recesses and projections of the satin surface.

As a result, the formation of an oil film between the outer bottom surface 52 and the inner floor surface 24 prevented due to the displacement effect, in turn, a sufficient frictional resistance between the outer bottom surface 52 and the inner floor surface 24 ensures.

The outer floor surface 52 of the housing 13 can be satin finished by electrical discharge machining or laser machining. Preferably, however, it is satinized by shot peening, as by shot peening the outer bottom surface 52 of the housing 13 is hardened, whereby its wear resistance is increased, which in turn allows the frictional resistance between the outer bottom surface 52 and the inner floor surface 24 over a prolonged period of time.

As in 18 shown, the ground can 17 of the housing 13 a conical outer edge surface 55 having a downwardly decreasing diameter, and a conical inner peripheral surface 54 is coupled to the mounting hole 6 is formed and has a downwardly decreasing diameter to carry an axial force which is applied to the housing 13 on the conical inner edge surface 54 is created.

With this arrangement, when through the arm 7 a force on the adjusting screw 16 is applied, which seeks to push the adjusting screw, by the wedge effect, a high surface pressure between the conical outer edge surface 55 and the conical inner edge surface 54 generates sufficient frictional resistance between the conical outer edge surface 55 and the conical inner edge surface 54 ensures.

As in 19 can show a depression 56 in the outer bottom surface 52 of the housing 13 be formed with the exception of its outer edge, leaving only the outer edge of the outer floor area 52 of the housing 13 Contact to the inner floor surface 24 of the mounting hole 6 Has.

With this arrangement focuses, if through the arm 7 a force on the adjusting screw 16 is applied, which is the adjusting screw 16 to push in, the frictional resistance between the outer bottom surface 52 of the housing 13 and the inner floor surface 24 of the mounting hole 6 is generated on the radial outside, so that it is possible to ensure a sufficient frictional resistance to the rotation of the housing 13 to prevent.

In the same way, a depression (not shown) in the inner bottom surface 24 of the mounting hole 6 be formed with the exception of its outer edge, leaving only the edge of the inner bottom surface 24 of the mounting hole 6 Contact to the outer inner floor surface 52 of the housing 13 Has. Even with this arrangement, the frictional resistance concentrates between the outer bottom surface 52 the housing and the inner bottom surface 24 of the mounting hole 6 on the radial outside, so that it is possible to have a sufficient frictional resistance for preventing the rotation of the housing 13 sure.

As in 20 shown, the ground can 17 of the housing 13 in an inner edge part 57 be pressed with a small diameter (ie by a press fit) on the mounting hole 6 is formed and has a smaller diameter than the outer diameter of the soil 17 of the housing 13 ,

With this arrangement, by pressing a high surface pressure between the ground 17 and the inner edge part 57 produced with a small diameter, which has a sufficient frictional resistance between the ground 17 of the housing 13 and the inner surface of the mounting hole 6 ensures.

Because the case 13 without excess at its part above the ground 17 is attached, it is possible the possibility of deformation of the internal thread 14 to minimize when the housing is pressed. To a deformation of the internal thread 14 to minimize, when the housing is pressed, a large-diameter outer peripheral area (not shown) on the floor 17 of the housing 13 be formed in the mounting hole 6 is pressed. Because the entire step of inserting the case 13 in the mounting hole 6 However, with this arrangement, it is difficult to insert the housing into the mounting hole. On the other hand, when inserting the soil 17 of the housing 13 in the inner edge part 57 with small diameter only the last stage of the step of inserting the housing 17 in the mounting hole 6 a press-fit, so that the housing can be easily inserted into the mounting hole.

As in 21 shown can be made of a rubber or an elastomeric plate 58 between the outer bottom surface 52 of the housing 13 and the inner floor surface 24 of the mounting hole 6 be arranged to stand on the plate 58 to carry an axial force on the housing 13 is applied.

With this arrangement, the frictional resistance between the outer bottom surface 52 and the inner floor surface 24 bigger than if the outer bottom surface 52 in direct contact with the inner floor surface 24 is so that it is possible to have a sufficient frictional resistance for preventing the rotation of the housing 13 sure.

As in 22 shown can be a seat made of iron 59 in the mounting hole 6 be attached so that the seat 59 the inner floor surface 24 of the mounting hole 6 forms and it carries an axial force on the housing 13 is applied.

With this arrangement, it is because the inner bottom surface 24 of the mounting hole 6 Made of iron, less likely that the inner bottom surface 24 of the mounting hole 6 Wears even if the cylinder head is made of aluminum. This will reduce the friction coefficient of the inner bottom surface 24 minimized over time and thus a sufficient frictional resistance between the ground 17 of the housing 13 and the inner surface of the mounting hole 6 ensured.

As in 23 shown can be a cylindrical iron sleeve 61 that has a bottom and with the mounting hole 6 is formed in a foot hole 60 be pressed in that in the upper surface of the cylinder head 2 is designed to fit on the sleeve 61 to carry an axial force on the housing 13 is applied.

With this arrangement, it is because the inner surface of the mounting hole 6 Made of iron, less likely that the inner surface of the mounting hole 6 Wears, even if the cylinder head 2 made of aluminum. As a result, there is sufficient frictional resistance between the ground 17 of the housing 13 and the inner surface of the mounting hole 6 ensured. Also, there is no difference in contraction between the sleeve 61 and the housing 13 Even when the ambient temperature rises, the case stays firmly in the mounting hole 6 attached.

Summary

The object is to prevent rotation of the housing when a force acts on the adjusting screw, which seeks to push in the adjusting screw.

The lash adjuster comprises a cylindrical housing 13 that a floor 17 and in a mounting hole 6 is included in an upper surface of a cylinder head 2 is formed, wherein the housing 13 an internal thread 14 on an inner periphery thereof, an adjusting screw 16 that has an external thread 15 on an outer circumference thereof, which threaded into the female thread 14 of the housing 13 is, and a return spring 18 between the adjusting screw 16 and the floor 17 of the housing 13 is arranged and the adjusting screw 16 biased in one direction from the housing 13 projects upwards, with the adjusting screw 16 a projected end 22 that is from the housing 13 protrudes and is designed, an arm 7 rotatably support a valve train, wherein a rotation-preventing projection 27 on the ground 17 of the housing 13 is provided in an attachment opening 26 It is fixed in an inner floor area 24 of the mounting hole 6 is formed, and thereby a rotation of the housing 13 prevented.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• JP 2005-273510A [0008]
• JP 64-34407 A [0008]

Claims (22)

A clearance compensation device comprising a cylindrical housing ( 13 ), which has a floor ( 17 ) and in a mounting hole ( 6 ) received in an upper surface of a cylinder head ( 2 ) is formed, wherein the housing ( 13 ) an internal thread ( 14 ) has on an inner periphery thereof, an adjusting screw ( 16 ), which has an external thread ( 15 ) has on an outer periphery thereof, in threaded coupling to the internal thread ( 14 ) of the housing ( 13 ), and a return spring ( 18 ) between the adjusting screw ( 16 ) and the ground ( 17 ) of the housing ( 13 ) and the adjusting screw ( 16 ) are biased in a direction that they from the housing ( 13 ) upwards, with the adjusting screw ( 16 ) a protruding end ( 22 ), which from the housing ( 13 ) protruding and shaped, an arm ( 7 rotatably supporting a valve gear, characterized in that the lash adjuster further comprises a rotation prevention device for preventing rotation of the housing ( 13 ) contains. A clearance compensation device according to claim 1, wherein said rotation prevention device has a rotation prevention projection (10). 27 ), which is on the ground ( 17 ) of the housing ( 13 ) is provided, and a mounting opening ( 26 ) located in an inner floor surface ( 24 ) of the mounting hole ( 6 ) is provided, wherein the rotation-prevention projection ( 27 ) in the attachment opening ( 26 ) is attached. A clearance compensation device according to claim 2, wherein the rotation prevention projection is a projection (Fig. 27 ), which is a D-shaped cut out part ( 28 ) at an outer periphery thereof. A clearance compensation device according to claim 2, wherein the rotation prevention projection is a projection (Fig. 32 ), the two bevels ( 31 ) at an outer periphery thereof. A clearance compensation device according to claim 2, wherein the rotation prevention projection is a projection (Fig. 35 ), which has the shape of a regular polygonal column. A clearance compensation device according to claim 2, wherein the rotation prevention projection is a projection (Fig. 37 ) which is from an axis of the housing ( 13 ) is offset. A clearance compensation device according to any one of claims 2 to 6, wherein the attachment opening ( 26 ) one end of a ventilation hole ( 25 ) extending from the inner bottom surface ( 24 ) of the mounting hole ( 6 ) extends to the outside. A clearance compensator according to claim 7, wherein a through-hole (FIG. 30 ) vertically through the ground ( 17 ) of the housing ( 13 ), a lower end thereof to a free end of the rotation preventing projection (FIG. 27 ) is open. A clearance compensation device according to claim 1, wherein the rotation preventing device is a friction ensuring device for controlling the frictional resistance between the ground (FIG. 17 ) of the housing ( 13 ) and the inner surface of the mounting hole ( 6 ) and thereby the rotation of the housing ( 13 ) to prevent. A clearance compensator according to claim 9, wherein said friction ensuring means comprises an oil film expelling groove (10). 53 ) located in an outer bottom surface ( 52 ) of the housing ( 13 ) is trained. A clearance compensation device according to claim 9, wherein the friction ensuring means comprises a satinized surface formed in an outer bottom surface ( 52 ) of the housing ( 13 ) is trained. A clearance compensator according to claim 11, wherein the frosted surface is formed by shot peening. A clearance compensation device according to claim 9, wherein said friction ensuring means comprises a conical outer peripheral surface ( 55 ) located on the ground ( 17 ) of the housing ( 13 ) and has a downwardly decreasing diameter, and a conical inner peripheral surface ( 54 ) at the mounting hole ( 6 ) and has a downwardly decreasing diameter, wherein the conical outer peripheral surface ( 55 ) in the conical inner peripheral surface ( 54 ) intervenes. A clearance compensator according to claim 9, wherein the friction ensuring means comprises a recess ( 56 ) located in an outer bottom surface ( 52 ) of the housing ( 13 ) is formed with the exception of its outer edge, or a depression formed in the inner bottom surface ( 24 ) of the mounting hole ( 6 ) is formed with the exception of its outer edge. A clearance compensation device according to claim 9, wherein said friction ensuring means comprises an inner peripheral part ( 57 ) with a small diameter, which on the mounting hole ( 6 ) is formed, wherein the bottom ( 17 ) of the housing ( 13 ) in the inner peripheral part ( 57 ) is pressed with a small diameter. A clearance compensation device according to claim 9, wherein the friction ensuring device is a made of rubber or an elastomeric plate ( 58 ) formed between an outer floor surface ( 52 ) of the housing ( 13 ) and an inner floor surface ( 24 ) of the mounting hole ( 6 ) is arranged. A clearance compensation device according to claim 9, wherein the friction ensuring means comprises a seat ( 59 ) made of iron and having an inner bottom surface ( 24 ) of the mounting hole ( 6 ). A clearance compensator according to claim 9, wherein the friction ensuring means comprises a sleeve ( 61 ), which is made of iron and the mounting hole ( 6 ). A clearance compensation device according to any one of claims 1 to 18, wherein the return spring ( 18 ) is a compression coil spring, the axial force on the adjusting screw ( 16 ), which the adjusting screw ( 16 ) out of the housing ( 13 ) tries to push. A clearance compensation device according to any one of claims 1 to 18, wherein the return spring ( 18 ) is a torsion spring, the torque on the adjusting screw ( 16 ), which the adjusting screw ( 16 ) out of the housing ( 13 ) tries to push. A lash adjuster according to claim 20, wherein the torsion spring is a torsion coil spring, a coil spring or an evolute spring. A clearance compensation device according to any one of claims 1 to 21, wherein the external thread ( 15 ) and the internal thread ( 14 ) Are pointed thread, trapezoidal thread or sawtooth-shaped thread.

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