JPH01227809A - Intake/exhaust valve actuating device for internal combustion engine - Google Patents

Abstract

PURPOSE:To make it possible to constantly set the most suitable valve lift curve by providing two rotary bodies which respectively rotate in response to a crankshaft and a camshaft, and making eccentric amount of two directions, which perpendicularly intersect axial directions of the rotary bodies, optionally changeable. CONSTITUTION:A camshaft 12a, to which rotation of a gear 8a is transmitted via an Oldam's coupling 10a and a transmitting device of inconstant velocity 11a, is provided in an intake/exhaust valve actuating device in which rotation of a crankshaft is transmitted via a cogged belt 9 which is hung around the gear 8a, etc. The transmitting device of inconstant velocity 11a is composed of the first block 23, which supports a minor shaft 21 of the Oldam's coupling 10a via a ball bearing 22 and which is displaced in the direction of x by making a motor 31 rotate, and the second block 25 which is displaced in the direction of y by making a motor 30 rotate. The eccentric amount between the minor shaft 21 of the Oldam's coupling 10a and the camshaft 12a is made to be option ally changeable in the direction of x, y by making the both motors 30, 31 rotate.

Description

[Detailed Description of the Invention] [Object of the Invention] <Industrial Application Field> The present invention relates to the operation of intake and exhaust valves that can change the opening/closing timing of the intake and exhaust valves in order to improve the efficiency or fuel efficiency of an internal combustion engine. Regarding equipment.

<Prior Art> It is known that the efficiency or fuel efficiency of an internal combustion engine is strongly affected by the opening/closing timing of intake and exhaust valves, and it is important in the design of an internal combustion engine to appropriately determine the cam profile of the intake and exhaust valve actuating device. This is one of the important factors for However, since the optimal opening/closing timing of the intake and exhaust valves depends on the load or rotational speed of the engine, it is not possible to always determine the optimal opening/closing timing of the intake and exhaust valves from a low speed range to a high speed range. Therefore, Japanese Patent Application Laid-open No. 54-30310 or Japanese Patent Application Laid-open No. 59-
No. 113229 discloses that an inconstant rotation transmission means is interposed between a camshaft and a crankshaft, and the amount of eccentricity in the transmission means is changed according to the operating conditions of the internal combustion engine.
Techniques have been proposed that constantly optimize the opening and closing timing of intake and exhaust valves. However, in the inventions described in these publications, although it is possible to change the overlap between the intake and exhaust valves or the extent of the opening section of the intake and exhaust valves, the timing when the lift of the intake and exhaust valves is maximum is changed. cannot be said to be sufficient for the purpose of achieving strict optimization of the opening/closing timing of intake and exhaust valves.

<Problems to be Solved by the Invention> In view of the problems of the prior art, the main object of the present invention is to not only change the width of the opening section of the intake and exhaust valves of an internal combustion engine, but also to change the width of the opening section of the intake and exhaust valves of an internal combustion engine. To provide an improved intake/exhaust pulp operating device capable of changing the opening/closing timing of intake/exhaust valves with a large degree of freedom so as to arbitrarily change the point at which the lift product of the valve reaches its maximum.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, an intake and exhaust valve operating device capable of controlling the opening/closing timing of intake and exhaust valves of an internal combustion engine is provided. a first rotating body that rotates proportionally to the camshaft; a second rotating body that rotates proportionally to the camshaft; a diametrical slot provided in either of the rotating bodies; and a diametrical slot received in the slot. a transmission means having a pin provided on either one of the two rotating bodies, and an adjusting means for changing the amount of eccentricity in two directions orthogonal to the axial direction of the two rotating bodies. This is achieved by providing eight intake and exhaust valve actuation positions for an internal combustion engine.

<Operation> The eccentric direction of the transmission means is set perpendicular to the rotational axis direction.
By adjusting the direction, the inconsistency between both rotating bodies can be freely controlled, so both the opening/closing timing and the length of the opening/closing section of the intake and exhaust valves can be freely controlled. This makes it possible to strictly optimize the lift curves of the intake and exhaust valves themselves.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 show a single cylinder four-stroke engine to which the present invention is applied. A piston 2 slidably received in a cylinder 1 is connected to a small end of a connecting rod 4 via a piston pin 3, and a large end of the connecting rod 4 is connected to a crank pin 6 of a crankshaft 5. The rotation of the crankshaft 5 is transmitted to the intake and exhaust valve actuating device at a reduction ratio of 1/2 by a cogged belt 9 that is rotated through a gear 7 on the crankshaft side and gears 8a and 8b on the intake and exhaust valve actuating device side. . Here, since the intake and exhaust valves are arranged symmetrically, only the intake valve side will be described below.

The rotation of the gear 8a on the intake/exhaust valve operating device side is transmitted to the camshaft 12 via an Oldham joint 10a and an inconstant velocity transmission device 11a.
transmitted to a. The camshaft 12a is provided with a pair of cams 13a, each of which opens and closes two intake valves 15a via an arm 14a, corresponding to each stroke of the internal combustion engine performed in the combustion chamber 16. The valve 15a is opened and closed as shown in FIG.

The Oldham joint 10a rotates integrally with the gear 8a and includes a disc 17 having a slot extending in the diametrical direction, a joint member 18 having a protrusion 19 that slidably fits into the slot, and a ball bearing 22. It has a short shaft 21 rotatably supported by an inner race. The joint member 18 is provided with a second protrusion 20 perpendicular to the protrusion 19 on the opposite side of the protrusion 19.
is slidably fitted into a diametrical slot provided in the short shaft 21. In this way, even if the disk 17 and the short shaft 21 are eccentric to each other, constant velocity power transmission is performed.

The inconstant velocity transmission device 11a includes a first block 23 that supports the outer race of the ball bearing 22, and a second guide member 24 that slidably guides the block 23 in the X direction shown in FIG. block 25. The second block 25 is slidably guided in the y direction in FIG. 2 by guide means (not shown). The second block 25 supports a motor 31, and a threaded rod 33 extending in the X direction connected to the output shaft of this motor is
It is screwed into a female screw provided in the first block 23. The motor 30 is fixed to a fixed part (not shown), and a threaded rod 32 extending in the y direction is connected to this output shaft, and this threaded rod 32 is connected to the second block 25.
It is screwed into a female threaded hole provided in the.

Further, a disc 26 is coaxially formed at the other end of the short shaft 21, and an axial pin 27 is integrally protruded from the other end of the disc 26 at a position near the outer periphery. There is. This pin 27 is received in a diametrical slot 28 provided in the outer end face of a disk 29 integrally formed at one end of the camshaft 12a.

Therefore, according to this embodiment, by rotating the motor 30, the second block 25 is displaced in the y direction, and by rotating the motor 31, the first block 23 is displaced in the X direction relative to the first block 11a. can be displaced in the direction. Such displacement of both blocks in the x and y force directions is permissible because the Oldham joint 1Qa is used. Furthermore, by rotating both motors 30 and 31, the amount of eccentricity between the short shaft 21 and the camshaft 12a can be arbitrarily changed in both the x and y directions.

FIG. 3 shows the relationship between the input and output ports J in the embodiment shown in FIGS. 1 and 2, that is, the rotation angle θ of the disc 26 and the circle on the camshaft side. Rotation angle φ of plate 29
It is a model diagram for showing the relationship between. In FIG. 3, the amount of eccentricity between the two discs 26 and 29 is δ, the eccentric direction is γ, and the amount of eccentricity of the pin 27 with respect to the center of rotation of the disc 26 is R.
1. If the eccentricity of the position of the slot portion that contacts the pin 27 with respect to the center of rotation of the circular plate 29 is r, then the following first
The formula is obtained.

R81nθ-rsinφ+δ5in7□)...(1) RCO5θ=rcosφ+δcos7' This can be rearranged as shown in the second and third equations.

R31nθ −δ5in7 tanφ−□…(2) RCO5θ −δCOSγ sinθ −εsinγ tanφ=□…(3) COSθ −εCOSγ 1ot,, ε−δ/R Crankshaft angle (2θ) when changing the dimensional eccentricity ε and eccentricity direction γ (the speed is reduced to 1/2 from gear 7 of the crankshaft to gear 8a on the valve actuating device side) The graph shows the relationship between the angle and the camshaft angle (φ) and the valve lift relative to the crankshaft angle. Here, α represents the ratio of the rotational speed of the inconstant velocity transmission device 11a to the rotational speed of the camshaft 12a.

It can be seen from these graphs that the lift curve of the valve can be freely set by appropriately selecting γ and ε. In particular, when γ is set to O and ε is changed as shown in FIG. 4, only the opening/closing timing of the valve can be changed without relatively changing the width of the opening amount of the valve. Furthermore, as shown in Fig. 6, when γ is set to 75 degrees, changing ε will not substantially change the point where the valve lift is maximum, but will only change the width of the valve opening amount. be able to. When γ is set to an angle other than these angles and ε is changed, the change in the lift curve of a valve having an intermediate tendency between these two directions is 1q.

Note that the above embodiment relates to a single-cylinder engine, and if this is applied to, for example, a two-cylinder engine, the tendency of inconsistency between the crankshaft and the camshaft may change, for example, due to the angle of the crankshaft. is symmetrical about the point where 180fi is, so the valve lift curves between the cylinders are changed in opposite directions, making it impossible to achieve good results. To solve this problem, for example, the transmission speed ratio between the gear 7 and the gear 8a is set to 1, and a 1/2 reduction mechanism is provided between the output side of the inconstant velocity transmission device 11a and the camshaft 12a. (α=2).

FIG. 10 shows such an embodiment, in which the gear ratio of gear 8a to gear V7 is 1:1, and a small diameter portion 34 is provided coaxially and integrally protruding from disk 29. An external gear 35 is mounted on a disc 3 provided at one end of the camshaft 12a.
1 by meshing with the internal gear 37 provided in 6.
/2 reduction ratio can be achieved. According to this embodiment, as shown in FIG. 11, the inconsistency between the crankshaft and the camshaft is repeated every time the crankshaft rotates 360 degrees, that is, every time the camshaft rotates 180 degrees. Thus, while the crankshaft in a four-stroke engine rotates 720 degrees, it is possible to drive, for example, the intake and exhaust valves of two cylinders to open and close in the same way with a phase difference of 360 degrees.

However, since the non-uniform speed section will be shortened overall,
Compared to the previous embodiment, the degree to which the valve lift curve is changed is reduced. However, if the gear ratio between the gears 7.8a and the gear ratio between the gears 35.37 are appropriately selected in this way, the present invention can be applied to an internal combustion engine having any number of cylinders.

Figure 12 shows that the input side of the inconstant velocity transmission device is increased in speed by 3/2 of the crankshaft, and the rotational speed of the output side of the inconstant velocity transmission means is reduced to 1/3 and transmitted to the camshaft. This figure shows an example of the characteristics of the embodiment (α=3), which can be suitably applied to, for example, a three-cylinder engine.

The embodiment shown in FIGS. 13 and 14 has 4 cycles 4
It concerns a cylinder engine. In this embodiment, one inconstant velocity transmission device is used for two cylinders having a 360 degree phase difference (crankshaft), and two
For example, intake valves 15a and 15a' of four cylinders are controlled using two inconstant velocity transmission devices 11a and 11a'. A cogged belt 9a wound around a gear 7 fixed to the crankshaft 5, a gear 7a fixed to the intermediate shaft 38, another gear 7b fixed to the intermediate shaft 38, and an Oldham joint 10a.

A cogged belt 9 is wound around a gear 7C fixed to the input shaft of the inconstant velocity transmission device 11a, 118' having a speed of ioa'.
b, from the crankshaft 5 to the inconstant velocity transmission device 11a.
, 11a', the rotation is transmitted at a reduction ratio of 1:1, and gears 7d and cams 13a, 13 for driving valve opening and closing are fixed to the output shafts of the inconstant velocity transmission devices 11a, 11a'.
The cogged belt 9G wound around the gears 8a, 5a' fixed to the camshafts 12a, 12a' having a Rotation is transmitted at a reduction ratio of /2 (α=2).

In this embodiment as well, the actuating device on the exhaust valve side may have the same structure as the actuating device on the intake valve side, so a detailed explanation thereof will be omitted as in the case of the previous embodiment. ing.

In addition, since it is generally difficult to increase the eccentricity ε in the high rotational speed range, the eccentricity ε should be relatively large in the low speed range, and the eccentricity ε should be compared in the high speed range. It is desirable to define the profile of the cam 13a such that a suitable result is obtained when the target is made smaller.

[Effects of the Invention] As described above, according to the present invention, by operating the actuator that can be adjusted in two directions, such as the motor 30, 31, as appropriate depending on the rotational speed and load of the engine, the valve can always be optimally adjusted. A lift curve can be set, and low fuel consumption or high output of the engine can be suitably achieved.

[Brief explanation of the drawing]

FIGS. 1 and 2 are a schematic side view and a front view, partially cut away, showing a case where the valve operating device according to the present invention is applied to a single-cylinder four-stroke engine. FIG. 3 is a model diagram showing the relationship between the hand saw angles of the inconstant velocity transmission device shown in FIGS. 1 and 2. FIG. Figures 4 to 9 show changes in the camshaft angle and valve lift amount with respect to the crankshaft angle when the eccentricity and eccentric direction are changed in the embodiment shown in Figures 1 and 2. This is a graph showing. FIG. 10 is a partially cutaway enlarged side view of a main part showing a second embodiment of the valve operating device according to the present invention, which is suitable for a multi-cylinder engine. FIGS. 11 and 12 are graphs similar to those of FIGS. 4 to 9 illustrating examples of characteristics suitable for two-cylinder and three-cylinder engines, respectively, of the valve actuator according to the present invention. FIGS. 13 and 14 are views similar to FIGS. 1 and 2, showing an embodiment in which two sets of valve operating devices according to the present invention suitable for a two-cylinder engine are applied to a four-cylinder engine. 1... Cylinder 2... Piston 3... Piston pin 4... Connecting rod 5... Crankshaft 6... Crank pin 7. 8... Gear
9... Cogged belt 10... Al dam joint 11.
...Inconstant velocity transmission device 12...Camshaft 13...
・Cam 14...Rocker arm 15...Valve 16
...Combustion chamber 17...Disk 18...Joint member 19.20...Protrusion 21...Short axis
22...Ball bearing 23...Block 24...
・Guide member 25...Block 27...Pin 28...Slot 29...Disk 30.31.
...Motor 32.33...Threaded rod 34...Small diameter part 35...External gear 36...Disk
37...Internal gear 38...Intermediate shaft patent applicant Honda Motor Co., Ltd. representative
Attorney, Patent Attorney Yo Oshima -, Figure 2 Figure 3 Police Figure 4 Figure 5z Figure 6 Figure 7 Figure 82 ME9 Figure 10

Claims (1)

[Claims] (1) An intake and exhaust valve operating device capable of controlling the opening and closing timing of intake and exhaust valves of an internal combustion engine, which includes a first rotating body that rotates in proportion to the crankshaft, and a second rotating body that rotates in proportion to the camshaft. a rotating body; a transmission means having a diametrical slot provided in one of the rotating bodies; and a pin provided in the other of the rotating bodies to be received in the slot; 1. An intake and exhaust valve operating device for an internal combustion engine, comprising: adjusting means for changing the amount of eccentricity in two directions perpendicular to the axial direction of a body.