JPS6337441Y2 - - Google Patents

Description

[Detailed description of the invention] This invention uses a slider that moves linearly in the direction of the camshaft to cause the relative rotation of a pair of sleeves on the crankshaft side and the camshaft side, thereby timing the opening and closing of the intake and exhaust valves. This invention relates to an improvement of a device that performs variable control of.

Some internal combustion engines allow for variable control of valve timing in order to obtain maximum output depending on the rotational speed of the engine. To this end, various proposals have been made in the past, among which one proposed by the present applicant involves forming slits that intersect with each other on the circumferences of a pair of sleeves on the crankshaft side and the camshaft side. A slider that moves linearly in the direction of the camshaft is fitted into one of the sleeves, and a bearing shaft that extends in a direction perpendicular to the camshaft is attached to the slider,
A bearing contacting the intersecting slit mate is carried on the bearing shaft. The linear motion of the slider is converted by bearings located in intersecting slits into equivalent rotational motion of the pair of sleeves, thereby controlling valve timing. Such a valve timing switching device can eliminate backlash compared to conventional differential gear type or planetary gear type, and is therefore advantageous in terms of noise, transmission efficiency, and reliability.

In this type of valve timing control device, a pair of sleeves receives linear motion from a slider to change their relative angles. Therefore, it is necessary to install both sleeves so that they rotate relative to each other and do not move out of position in the axial direction.
For this reason, in the prior patent, a bearing was arranged between the sleeves, and the inner race and the outer race were attached to each sleeve using a snap spring or the like. However, it has the disadvantage of becoming structurally complex. In addition, the sleeve does not rotate all the time, but rotates only intermittently when switching the valve timing, so there is a drawback that the oil film cannot be smoothly supplied to the bearing surface.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a structure for attaching a pair of sleeves in a simple structure and capable of relative rotation without friction loss.

The present invention will be explained below with reference to the drawings. In Fig. 1, the valve timing control device of the present invention is shown as follows.
A timing pulley C is provided between a camshaft B rotatably supported by a cylinder head A of an internal combustion engine and a timing pulley C as a rotational drive member that receives rotation of a crankshaft (not shown) and transmits the rotation to the camshaft B. The entire timing belt cover D is housed inside the timing belt cover D. First, the camshaft side members of the device of the present invention will be explained. The shaft end of the camshaft B is connected to an inner sleeve 6 by a washer 4 and a bolt 5.
is fixed. Inner sleeve 6 and camshaft B
A detent pin 8 is inserted between the two members to prevent relative rotation between these members.

An outer sleeve 10 and a case 12 are attached to the timing pulley C with bolts 9. The outer sleeve 10 and the inner sleeve 6 are attached to be rotatable relative to each other, as will be described later.

Slits 13 and 14 are formed in the circumferences of the relatively rotatable inner sleeve 6 and outer sleeve 10 at diametrically opposed and symmetrical positions, respectively. As shown in FIG. 3, the slits 13 and 14 are formed so as to be inclined in opposite directions to each other and intersect with the axial direction of the camshaft B.
In the slits 13 and 14, independently rotatable roller bearings 15 and 16 are located, respectively. As shown in FIG. 2, the centers of the slits 13 and 14 are offset from the center lines of the roller bearings 15 and 16. For a pair of adjacent slits 13, 14, the offset axes are located on opposite sides of the center line of the bearing.
That is, one surface 13A, 14A facing each other contacts the bearings 15, 16 with a predetermined preload, and the other surface 13B, 14B facing each other contacts the bearing 15, 16 with a gap Y.
have. Therefore, with respect to the linear movement of the bearings 15 and 16 in the direction of the arrow X, the sleeves 6 and 10
A smooth rotational movement can be obtained. Furthermore, for the slits 13 in diametrically opposite positions, the offset axes are located on the same side with respect to the center of the bearing, and the same is true for the slits 14. This is to cope with alternating loads applied to the camshaft.

One side of the sleeve, in the example shown, the inner sleeve 6
A slider 17 is provided so as to be horizontally slidable in the direction of the camshaft B. The slider 17 integrally has a bearing shaft portion 17' extending in a direction perpendicular to the camshaft B, and the aforementioned bearings 15 and 16 are provided on this bearing shaft 17'.

21 is a rotary drive motor such as an electric motor or a hydraulic motor, which is fixed to the timing pulley cover D.
A threaded thread 22A is formed on the output shaft 22 of the motor 21 and is connected to the internal thread 23A of the drive sleeve 23 via a ball 29. Sleeve 23
has a slide groove 24 extending in the axial direction, which is located inside the annular guide 25 (which also serves to receive the inner race of the bearing 26 supporting the case 12), which is a member integral with the housing of the motor 21. It fits into an axial protrusion 27 formed on the periphery. Thus, the rotation of the motor output shaft 22 is caused by the groove 24.
is converted into linear motion by being guided by the protrusion 27. The drive sleeve 23 is connected to the slider 17 by a bearing 28. The bearing 28 serves to transmit the movement of the drive sleeve 23 to the slider 17 and also to rotatably support the slider 17 on the sleeve 23.

The inner sleeve 6 and the outer sleeve 10 are rotatably fitted into each other and have a cylindrical outer surface and a cylindrical inner surface facing each other. In this embodiment, a guide protrusion 6A having an arcuate cross section and extending in the circumferential direction is formed on the outer surface of the inner sleeve 6, as shown in FIG. On the other hand, on the inner surface of the outer sleeve 10, as shown in FIGS. 1 and 5, one circumferential groove 10A into which a guide projection 6A is fitted is formed over the entire circumference. As shown in FIGS. 4 and 5, the outer sleeve 10 further has an axial insertion groove 10B that opens into the groove 10A at one end and extends to the outer end surface of the sleeve at the other end.
The width d of this axial insertion groove is the circumference l of the guide projection 6A.
It's a little bigger than that. Therefore, at the time of manufacturing, the fifth
Introduce the inner sleeve 6 in the axial direction as shown by arrow A in Figure 6 so that its guide protrusion 6A is inserted into the axial insertion groove 10B, and when the guide protrusion 6A reaches the circumferential guide groove 10A. By turning the inner sleeve in the direction of arrow B, the guide protrusion 6A is attached to the guide groove 10A. Preferably, a circumferential groove 6B is formed in the inner sleeve 6 on the camshaft side close to the fitting portion between the guide projection 6A and the guide groove 10A. O- for the seal inside this
The ring 34 is housed and comes into contact with the inner surface of the outer sleeve 10 to provide a sealing effect.

To describe the operation of the present invention described above, when the timing pulley C is rotated by the crankshaft via the timing belt or chain, the outer sleeve 10 rotates together with the pulley C, and the roller Camshaft B to bearing 16
A rotational force centered on is applied. Therefore, the slider 17 rotates, and its rotational force is applied to the slit 13 of the inner sleeve 6 via the shaft portion 17' and the roller bearing 15, and as a result, the inner sleeve 6
and camshaft B rotates. Therefore, a predetermined valve timing is obtained, which is determined when the cam on the camshaft B comes into contact with the push rod.

When the motor 21 is driven to control the valve timing, the rotational movement of the output shaft 22 is converted into the linear movement of the drive sleeve 23 by the action of the threaded portion, and as a result, the slider 17 moves to the left or right depending on the direction of rotation of the motor 21. move to. This left and right movement of the slider 17 is controlled by the bearings 15 and 16 via the shaft portion 17'.
The bearings 15 and 16 are transmitted to the slit 1.
3 and 14 while moving in the direction of arrow X in FIG. Then, since the slits 13 and 14 intersect, relative rotation occurs between the outer sleeve 10 and the inner sleeve 6, so that the positions of the crankshaft and the camshaft B change.

During this relative rotation between the inner sleeve 6 and the outer sleeve 10, the guide protrusion 6A and the guide groove 10A
The guiding action of the shaft ensures smooth rotation. Further, the O-ring 34 prevents oil from leaking to the outside.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view (shown along the - line in Fig. 2) of a valve timing control device according to the present invention, Fig. 2 is a cross-sectional view, and Fig. 3 is conceptually illustrated in the direction of Fig. 2. Fig. 4 is a partially cutaway perspective view of the inner sleeve and outer sleeve of the present invention in an assembled state, and Fig. 5 shows the inner sleeve and outer sleeve immediately before assembly. FIG. 6... Inner sleeve, 10... Outer sleep,
13, 14...Slit, 15, 16...Bearing, 17...Slider, 6A...Guiding protrusion, 10A...
Guide groove, 10B...axial insertion groove.

Claims (1)

[Scope of utility model registration request] A pair of mutually rotatable sleeves, one of which is connected to a camshaft of an internal combustion engine and the other to a rotational drive member that receives power from a crankshaft, and bored in directions that intersect with each other on the circumference of the pair of sleeves. a bearing is provided in the slit, the bearing is provided on a reciprocating means that moves in the direction of the camshaft;
The linear motion of the reciprocating means is exchanged with the relative rotational motion of a pair of sleeves, one of the pair of sleeves having an arcuate cross section on a cylindrical surface facing the other sleeve. A protrusion extending in the circumferential direction is formed on the other sleeve, and a guide groove extending in the entire circumferential direction into which the guide protrusion fits is formed on the cylindrical surface facing the one sleeve, and one end of the guide groove is formed on the cylindrical surface facing the one sleeve. A valve timing control device for an internal combustion engine, which is formed with an axial insertion groove that opens into the guide groove, extends to the outer end surface of the sleeve at the other end, and is slightly wider than the circumference of the guide projection.