WO2007015315A1

WO2007015315A1 - Direct-action valve lifter for internal combustion engine

Info

Publication number: WO2007015315A1
Application number: PCT/JP2005/015520
Authority: WO
Inventors: Masayasu Nagado; Teruaki Ando
Original assignee: Nittan, Valve, Co., Ltd.
Priority date: 2005-08-01
Filing date: 2005-08-26
Publication date: 2007-02-08
Also published as: EP1911940A4; JP2007040114A; KR101011427B1; US20090056659A1; JP4829562B2; EP1911940A1; KR20080033273A; CN101228337A

Abstract

[PROBLEMS] A direct-action valve lifter having reduced number of parts and simple structure and capable of being switched to high lift and low lift. [MEANS FOR SOLVING PROBLEMS] The valve lifter is interposed between a cam and a valve stem. The cam (20) has a high lift cam (22) and low lift cams (24) integrated together, and the valve lifter (30) has a side lifter (32) slidingly in contact with a low lift cam, a center lifter (40) slidingly in contact with a high lift cam, and a hydraulic means (hydraulic path)(11b) for sliding the center lifter (40) in order to switch the amount of valve lift between two stages of high and low. A slit (33) for causing the high lift cam to strike at the air is provided at the top of a cylindrical lifter body so that the lifter body functions as the side lifter (32) having low lift cam sliding contact surfaces (32a). A hole (34) orthogonal to the slit (33) is provided in the lifter body, and the piston-type center lifter (40) slid by hydraulic pressure is provided in the hole (34). When the center lifter (40) is at a position corresponding (not corresponding) to the slit (33), it is a high (low) lift mode. In the valve lifter, the number of parts is reduced and the structure is simple, a dimentional tolerance required for each part is relaxed, and work for assembling each part is simplified.

Description

Specification

Direct acting valve lifter for internal combustion engine

Technical field

[0001] The present invention relates to a cylindrical direct acting valve lifter interposed between a cam and a valve stem constituting a valve mechanism of an internal combustion engine, and in particular, a high lift cam and a low lift cam are integrated. Direct drive for internal combustion engines that can adjust the lift amount of the valve in two steps, high and low, by switching the side lifter with the low lift cam sliding contact surface and the center lifter with the high lift cam sliding contact surface to the cam unit It relates to a mold valve lifter.

Background art

[0002] As this type of direct acting valve lifter, one disclosed in Patent Document 1 below is known. Here, as shown in FIG. 11, a cylindrical lifter body 1 has a central center lifter 2 having a circular center cam sliding contact surface 2a corresponding to a low lift center cam at the top and a high lift at the top. It is divided into a cylindrical side lifter 3 having a ring-shaped side cam sliding contact surface 3a corresponding to the side cam, and a first connecting pin 5a is provided between the center lifter 2 and the through holes 4a and 4b extending over the side lifter 3. A second connecting pin 5b is disposed between 4b and 4c. Reference numeral 6 is a spring member for returning the first connecting pin 5a and the second connecting pin 5b to a predetermined position, and reference numeral 7 is interposed between the spring receiver 2b at the bottom of the center lifter 2 and the spring receiver 3b of the side lifter 3, This is a spring member that holds the center lifter 2 at a predetermined position in the vertical direction with respect to the side lifter 3.

[0003] If the first connecting pin 5a is in the through hole 4a, the center lifter 2 and the side lifter 3 are separated in the lifter axial direction (the vertical direction in FIG. 11) (the side lifter 3 sinks into the center lifter 2). The drive (low lift amount) by the center cam is transmitted to the lifter body 1 via the sliding surface 2a. On the other hand, the first connecting pin 5a and the second connecting pin 5b are moved to the right in FIG. 11 against the biasing force of the spring 7 by hydraulic pressure, and the first connecting pin 5a straddles between the through holes 4a and 4b. The center lifter 2 and the side lifter 3 are connected in the lifter axial direction via the first connection pin 5a and the second connection pin 5b, when the second connection pin 5b is located between the through holes 4b and 4c. Driven by side cam (high lift) Is transmitted to the lifter body 1 via the sliding contact surface 3a.

Patent Document 1: Special Table 2002—509219 (Figure 1, 2)

Disclosure of the invention

Problems to be solved by the invention

However, in Patent Document 1 described above, the cylindrical lifter body 1 has a structure in which the center lifter 2, the side lifter 3, the first connection pin 5a, the second connection pin 5b, the spring portion 6, and the spring member 7 are accommodated. There are many component parts.

[0005] In particular, in order for the lifter to operate smoothly, it is indispensable that the positional relationship between the connecting pin and the through-hole be matched with high accuracy. To that end, not only the dimensional accuracy of the pin 5a but also the connecting High dimensional accuracy is required for the hole shape of the lifter body 1 and all the components assembled to the lifter body 1, such as the dimensional accuracy of the receiver that contacts the pin 5a and the second connecting pin 5b, and the dimensional accuracy of the through hole. For this reason, there is a problem that the production cost becomes so high that mass production is difficult.

[0006] In addition, since a spring member 7 for holding the center lifter 2 at a predetermined position in the vertical direction with respect to the side lifter 3 is indispensable between the center lifter 2 and the side lifter 3, the low lift mode (the center lifter 2 and the side lifter 3 When the cam is rotating at high speed with the side lifter 3 being able to sink into the center lifter 2), the spring force of the spring member 7 is always applied to increase the sliding friction of the lifter. There was also a problem that smooth operation might be hindered.

[0007] The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide a linear motion interposed between a valve unit and a cam unit in which a high lift force and a low lift cam are integrated. An object of the present invention is to provide a direct-acting valve lifter for an internal combustion engine that has a simple configuration with a small number of components and can be switched between a high lift and a low lift and operates smoothly.

Means for solving the problem

[0008] In order to achieve the above object, in the direct acting valve lifter for an internal combustion engine according to claim 1, a circle interposed between a cam and a valve stem constituting a valve mechanism of the internal combustion engine. In a cylindrical direct acting valve lifter, the cam is a high lift cam and a low lift cam integrated. The noble lifter includes a side lifter that is in sliding contact with the low lift cam, a center lifter that is in sliding contact with the high lift cam, and a hydraulic means that operates the center lifter to switch the valve lift amount between two levels: high and low. A direct acting type valve lifter for an internal combustion engine,

A center cam idler slit extending in the cam sliding direction is provided at the top of the cylindrical lifter body to form a side lifter having a low lift cam sliding contact surface at the top, and the lifter body is orthogonal to the slit. And a piston type center lifter that is slid by hydraulic pressure is provided in the hole.

(Operation) The piston type center lifter slides along the hole by the acting hydraulic pressure, and when the center lifter is in a position corresponding to the slit, the high lift cam is slidably contacted with the center lifter. High lift is transmitted through the side lifter (lifter body). On the other hand, when the center lifter is in a position that does not correspond to the slit, the high lift cam fluctuates in the slit, the low lift cam slides on the side lifter, and the low lift amount is transmitted to the valve stem via the side lifter (lifter body). The

[0010] That is, the center lifter can slide along the hole by hydraulic pressure, and can alternatively take a form capable of sliding contact with the center cam and a form not sliding against the center cam.

Accordingly, the valve lifter is mainly configured by a cylindrical lifter body that is a side lifter and a piston-type center lifter that is disposed in a hole of the lifter body and slides by hydraulic pressure, and thus has a large number of components. Dimensional tolerances required for each component with fewer component parts compared to technology are alleviated, and the work of assembling each component is also simplified.

[0012] Further, unlike the prior art, a spring member for holding the center lifter at a predetermined position in the vertical direction with respect to the lifter body that is the side lifter is not provided. Therefore, in the low lift mode, the high lift force is swung in the slit. In addition, since the spring force of the spring member does not act as a load, smooth operation of the lifter is ensured even when the cam rotates at high speed in the low lift mode.

[0013] In Claim 2, in the linear motion type norelifter for the internal combustion engine according to Claim 1, the hole is configured as a circular hole and the center lifter is configured as a cylindrical type. (Operation) Since the center cam sliding contact surface is an arc surface, the length of the sliding contact surface with respect to the specified lift amount is shortened, and the size of the center lifter in the cam sliding direction can be reduced accordingly. The degree goes up.

[0014] According to Claim 3, in the linear motion type norelifter for an internal combustion engine according to Claim 1 or 2, the width of the slit for swinging the high lift cam is substantially equal to the width (plate thickness) of the high lift cam. It was designed to have a size that fits roughly.

(Operation) Between the cylindrical lifter main body and the cylinder bore which is the relative sliding surface thereof, for example, a vertical groove provided on the cylinder bore side and a protrusion on the lifter main body side engaged with the vertical groove are provided. The width of the slit for center cam idle swing almost matches the thickness of the center cam, so by setting the cam profile so that the center cam always engages with the slit, the center cam idle swing The slit and center cam function as a detent for the lifter body cylinder bore.

The invention's effect

As is apparent from the above description, according to the direct acting valve lifter for an internal combustion engine according to claim 1, since the number of component parts of the noble lifter is small, the dimensional tolerance required for each component part is reduced. At the same time, the work of assembling each component is simplified, so that the manufacturing cost of the valve lifter can be greatly reduced, and the valve lifter can be provided at a lower cost.

[0017] In addition, since the smooth operation of the lifter is ensured even during the high rotation operation of the cam in the low lift mode, which has been a problem in the past because the smooth operation of the lifter is hindered, uneven wear of the lifter lifter is ensured. Since there is no need for a spring member to hold the lifter for high lift, there is no need to consider the rotational speed limit due to the spring force and the spring tension, which increases the degree of freedom in engine design.

[0018] According to claim 2, since the dimension of the center cam in the cam sliding direction can be reduced, the degree of freedom in designing the cam and the valve lifter can be increased.

[0019] According to claim 3, if the high lift cam is always engaged with the slit for swinging the high lift cam, the lifter main body is not required to be provided with a separate detent means between the lifter body and the cylinder bore. Since the body is prevented from rotating with respect to the cylinder bore, the configuration of the lifter body and the cylinder bore is simplified accordingly.

BEST MODE FOR CARRYING OUT THE INVENTION

Next, embodiments of the present invention will be described based on examples.

FIGS. 1 to 5 show an embodiment of the present invention. FIG. 1 is a cross-sectional view around a direct acting valve lifter constituting an internal combustion engine valve operating mechanism according to an embodiment of the present invention. Is a cross-sectional view of the valve lifter with the center lifter in a position that does not correspond to the slit of the side lifter, Fig. 3 is a side view of the valve lifter (showing the right side force of the valve lifter shown in Fig. 2), and Fig. 4 is an exploded view of the valve lifter FIG. 5 is a perspective view, and FIG. 5 is a cross-sectional view of the center lifter in a state where the center lifter is in a position corresponding to the slit of the side lifter.

In these drawings, reference numeral 12 denotes an intake port provided in the cylinder head 10 of the automobile engine, and reference numeral 14 denotes an intake valve provided in the port 12. The intake valve stem (valve stem) 15 Protrudes into the cylinder bore 11 in the vicinity of the intake port 12 and is urged by the compression coil spring 16 in the direction to close the intake port 12.

[0023] Reference numeral 20 denotes a cam unit 20 in which low lift side cams 24, 24 are arranged on both sides of a high lift center cam 22. The cam unit 20 is disposed above the cylinder bore 11, and includes a cam unit 20 and a valve. A valve lifter 30 is interposed between the stems 15 so as to be able to slide in the bore 11 in the vertical direction.

As shown in FIG. 4, the valve lifter 30 is a lifter main body having a center cam 22 extending in the cam sliding direction at the top portion 22 and a slit 33 for air swing and having a pair of side cam sliding contact surfaces 32a and 32a at the top portion. A side lifter 32, a piston-type center lifter 40 slidably disposed in a through-hole 34 provided inside the side lifter 32 so as to be orthogonal to the extending direction of the slit 33, and the center lifter 40 are placed at predetermined positions. It consists mainly of a compression spring 39 that holds it. The through hole 34 is formed of a circular hole, the center lifter 40 is formed in a bottomed cylindrical shape that engages with the through hole 34, and the outer peripheral surface of the center lifter 40 is a center cam sliding contact surface 40a.

Reference numeral 36 denotes a plug that functions as a spring receiver that is press-fitted and fixed to a hole 35 provided in parallel with the through-hole 34 near the lower portion of the through-hole 34 on the opening side, and rotates around the bottomed cylindrical plug 36. A stop pin 37 is projected, and the pin 37 engages with the longitudinal groove 1 la on the cylinder bore 11 side to constitute a rotation stop means for the cylinder bore 11 (cams 22, 24) of the valve lifter 30.

[0026] In the plug 36, a bottomed cylindrical slide pin 38 is slidably disposed in the axial direction, and a compression coil spring 39 is interposed between the plug 36 and the slide pin 38, so that the center The connector 40 is biased in the direction in which the plug force also moves away (left direction in FIG. 2).

[0027] Symbol l ib is an oil passage provided in the cylinder head 10 and opening at a position opposite to the longitudinal groove 11a of the cylinder bore 11 (position facing the center lifter 40 of the valve lifter 30). The center lifter 40 is slid along the through hole 34 by the pressure of the engine oil, and the lift amount of the nozzle 14 is switched.

That is, when hydraulic pressure (high pressure) is applied to the center lifter 40 via the oil passage l ib, it is piled on the spring force of the spring 39 and slides along the through hole 34, and as shown in FIG. When the position 40 corresponds to the slit 33, the high lift center cam 22 comes into sliding contact with the center lifter 40 (sliding contact surface 40a thereof), and the valve stem 15 is connected via the center lifter 40 and the side lifter 32 (lifter main body). High lift amount is transmitted.

On the other hand, when the hydraulic pressure acting on the center lifter 40 is reduced, the center lifter 40 returns to the original position not corresponding to the slit 33 by the spring force of the spring 39, and as shown in FIG. Is swung in the slit 33, the low lift side cam 24 is in sliding contact with the side of the side lifter 32 (sliding contact surface 32a), and a low lift amount is transmitted to the valve stem 15 via the side lifter 32 (lifter body). The

[0030] In this manner, the center lifter 40 slides along the through hole 34 by the acting hydraulic pressure, and adopts a form in which it can slide in contact with the center cam 24 and a form in which it does not slide in contact with the center cam 24. Can do.

[0031] Further, since the center lifter 40 is formed in a cylindrical shape and the center cam sliding contact surface 40a is an arc surface, the length of the sliding contact surface 40a with respect to a predetermined lift amount is shortened. The degree of freedom in designing the center cam 24 and the valve lifter 30 is increased, for example, the dimension in the cam sliding direction, that is, the outer diameter of the center lifter 40 can be reduced.

FIGS. 6 and 7 show a direct acting valve lifter for an internal combustion engine according to a second embodiment of the present invention. FIG. 6 is a cross-sectional view of the valve lifter in a state where the center lifter is placed in a position corresponding to the slit of the side lifter, and FIG. 7 is a cross-sectional view of the valve lifter in a state where the center lifter is placed in a position not corresponding to the slit of the side lifter.

In the first embodiment described above, there is provided a detent means for the valve lifter 30 constituted by the detent pin 37 on the valve lifter 30 (side lifter 32) side and the vertical groove 11a on the cylinder bore 11 side. In the example, the width d of the center cam idle slit 33 is configured to substantially match the width (plate thickness) t of the center cam 22 and the profile of the center cam 22 is configured to always engage with the slit 33. Therefore, since the slit 33 and the center cam 22 function as a detent means for the cylinder bore 11 (cam unit 20) of the valve lifter 30, the detent means (as shown in FIG. The stop pin 37) is not required, and the structure of the valve lifter 30A and the cylinder bore 11 is simple.

In the first embodiment described above, the piston-type center lifter 40 is initially slit by the spring force of the compression coil spring 39 as shown in FIG. 2 when no hydraulic pressure (high pressure) acts on the center lifter 40. When the hydraulic pressure (high pressure) is applied to the center lifter 40, the center lifter 40 is positioned corresponding to the slit 33 as shown in FIG. However, in this second embodiment, the switching is opposite to that of the first embodiment, and the piston type center lifter 40A is configured to switch to the drive transmission mode of the high lift side cam 22. When the hydraulic pressure does not act on the center lifter 40A, as shown in FIG. 6, the position corresponding to the slit 33 (the high lift side cam) by the spring force of the compression coil spring 39 is used. When the hydraulic pressure is applied to the center lifter 40, it moves to the position corresponding to the slit 33 as shown in Fig. 7, and the driving force transmission mode of the low lift side cam 24 is achieved. Is configured to switch to

That is, reference numeral 38A is a bottomed cylindrical slide pin disposed in the hole 35, and is provided in the cylinder head 10 at a position facing the slide pin 38A (hole 35) of the valve lifter 30A. Oil passage 11c is open. A cap 44 having a spherical outer surface is disposed on the side opposite to the side where the slide pin 38A is disposed of the through-hole 34, and a compression coil spring 39 is interposed between the cap 44 and the piston-type center lifter 40A. Center lifter 40A is slide pin 38A Is held at a predetermined position corresponding to the slit 33.

[0036] Specifically, when hydraulic pressure (high pressure) acts on the slide pin 38A via the oil passage 11c, the center lifter 40A slides along the through-hole 34 by staking the spring force of the spring 39A. As shown in FIG. 7, when the position does not correspond to the slit 33, the high lift center cam 22 swings in the slit 33, and the low lift side cam 24 slides on the side lifter 32, and the valve stem 15 includes the side lifter 32. A low lift amount is transmitted through the (lifter body). On the other hand, when the hydraulic pressure acting on the slide bin 38A is reduced, the spring 39 returns to the original position not corresponding to the slit 33 by the spring force, and the high lift center cam 22 slides on the center lifter 40A as shown in FIG. A high lift amount is transmitted to the valve stem 15 via the center lifter 40A and the side lifter 32 (lifter body).

[0037] Others are the same as those in the first embodiment described above, and therefore, the same reference numerals are given to omit redundant description.

8 and 9 show a direct acting valve lifter for an internal combustion engine according to a third embodiment of the present invention. FIG. 8 is a cross-sectional view showing a state where the center lifter is in a position not corresponding to the slit of the side lifter. FIG. 6 is a cross-sectional view showing a state in which is placed in a position corresponding to the slit of the side lifter.

This third embodiment is an improvement over the first embodiment described above, but in the first embodiment, the spring force of the compression coil spring 39 is applied to the piston-type center lifter 40 via the slide pin 38. In this third embodiment, the bottomed cylindrical plug 36 with a locking pin 37 protruding is slid along the hole 35 provided in the center of the through hole 34. A spring receiving portion 41 corresponding to a slide pin that engages with the plug 36 is formed at the center portion of the center lifter 40B so that the spring force of the compression coil spring 39 acts directly on the center lifter 40B. The number of parts that make up the valve lifter 30B is so small.

[0040] Further, since the spring force of the compression coil spring 39 acts on the center portion of the center lifter 40B, the center lifter 40B slides smoothly.

Others are the same as those in the first embodiment described above, and therefore, the same reference numerals are given and the duplicated description is omitted.

In the first to third embodiments described above, the through hole 34 and the center lifter 40 (40A, 4 OB) is configured in a cylindrical shape !, but it is configured in a square shape.

[0043] Further, in the first to third embodiments described above, the force oil pressure configured to slide the piston by the spring force of the spring and the oil pressure is applied to the front and rear of the piston. Further, a configuration in which the use of the spring is omitted may be employed.

In the first to third embodiments described above, the valve lifter constituting the valve operating mechanism of the intake valve provided in the intake port has been described. However, the operation of the exhaust valve provided in the exhaust port is described. The present invention can be similarly applied to a valve lifter constituting the valve mechanism.

Brief Description of Drawings

FIG. 1 is a cross-sectional view of the periphery of a direct acting valve lifter for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the valve lifter in a state where the center lifter is in a position not corresponding to the slit of the side lifter.

FIG. 3 is a side view of the noble lifter (view of the valve lifter shown in FIG. 2 from the right side).

FIG. 4 is an exploded perspective view of the noble lifter.

FIG. 5 is a sectional view of the valve lifter in a state where the center lifter is in a position corresponding to the slit of the side lifter.

FIG. 6 is a cross-sectional view of a direct acting valve lifter for an internal combustion engine according to a second embodiment of the present invention, showing the state where the center lifter is housed in a position corresponding to the slit of the side lifter.

FIG. 7 is a cross-sectional view showing a state where the center lifter is in a position not corresponding to the slit of the side lifter.

FIG. 8 is a cross-sectional view of a direct acting valve lifter for an internal combustion engine according to a third embodiment of the present invention, showing the state where the center lifter is in a position not corresponding to the slit of the side lifter.

FIG. 9 is a right side view of the valve lifter.

FIG. 10 is a cross-sectional view showing a state where the center lifter is in a position corresponding to the slit of the side lifter.

FIG. 11 is a cross-sectional view of a conventional valve lifter.

Explanation of symbols 10 Cylinder head

11 Cylinder bore

11a Vertical groove

l ib, 11c oil passage

14 Intake valve constituting the valve mechanism 15 Valve stem

20 Cam unit constituting the valve mechanism

22 Center cam for high lift

24 Side cam for low lift

30, 30A, 30B Direct acting type

32 Side lifter (lifter body)

32a Side cam sliding contact surface

33 Slit for center cam idle swing

34 Through hole

39 Compression coil spring

40, 40A, 40B Piston type center lifter

40a Center cam sliding surface

d Center cam idle slit width t Center cam width (plate thickness)

Claims

The scope of the claims

[1] In a cylindrical direct acting valve lifter interposed between a cam and a valve stem constituting a valve mechanism of an internal combustion engine, the cam is configured by integrating a high lift cam and a low lift cam. The noble lifter includes: a side lifter with which the low lift cam is in sliding contact; a center lifter with which the high lift cam is in sliding contact; A direct acting valve lifter for an engine,

A slit for center cam idle swing extending in the cam sliding direction is provided at the top of the cylindrical lifter body, and a side lifter having a low lift cam sliding contact surface is formed at the top, and the slit and A direct acting valve lifter for an internal combustion engine, wherein a hole extending in a direction orthogonal to the hole is provided, and a piston type center lifter that slides by hydraulic pressure is disposed in the hole.

2. The direct acting valve lifter for an internal combustion engine according to claim 1, wherein the hole is a circular hole, and the center lifter is formed in a cylindrical shape.

3. The direct acting type norelifter for an internal combustion engine according to claim 1, wherein a width of the slit for swinging the high lift cam substantially matches a width (plate thickness) of the high lift cam.