JPH01240701A - Variable displacement-type reciprocating piston unit - Google Patents

Abstract

PURPOSE:To restrain the fluctuation of a compression ratio so as to keep time for operating an intake and an exhaust valves in their optimum conditions by forming an Oldham's coupling with No.1 main shaft, No.2 main shaft, and an intermediate joint member between them. and connecting a piston to the intermediate joint member. CONSTITUTION:No.1 main shaft 12 with its rotation center fixed, and No.2 main shaft which is in close contact with one end surface of an intermediate joint member 6 and is provided with a guide groove 15 or a slider 8 on the contact surface in its radial direction, are provided. The transfer track of the rotation center is established by a bearing lever 22. A piston 3 is connected to the intermediate joint member 6. Thus, the fluctuation of a compression ratio can be restrained, and time for operating an intake and an exhaust valves can be kept in their optimum conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a variable displacement heavy reciprocating piston device used as a reciprocating internal combustion engine or a reciprocating compressor.

A typical example of a conventional reciprocating piston device is a reciprocating internal combustion engine. This is configured so that the linear motion of a piston that reciprocates due to combustion pressure is transmitted to the crankshaft via a connecting rod and converted into rotational motion of the crankshaft.

Reciprocating piston devices are also used as compressors. In this case, conversely, the rotational motion of the crankshaft is converted into reciprocating linear motion of the piston via the connecting rod, thereby suctioning and compressing the fluid.

In this type of reciprocating internal combustion engine, a valve mechanism consisting of an intake valve and an exhaust valve is driven by a crankshaft via a timing belt or chain, and is opened and closed at predetermined opening and closing timings. There is.

Problems to be Solved by the Invention However, in the conventional reciprocating piston device using the piston crank mechanism as described above, the reciprocating stroke of the piston is fixedly determined only by the amount of eccentricity of the crank pin in the crankshaft. As a result, the capacity of the piston device, that is, the displacement as an internal combustion engine and the discharge amount as a compressor, is always constant.
cannot be changed.

Therefore, for example, in a gasoline engine, it is necessary to adjust the output by throttling a throttle valve in the intake passage during low-load operation, and there is a problem in that fuel consumption deteriorates due to the accompanying pumping loss.

Furthermore, when used as a compressor, it was necessary to turn on and off the compressor and to variably control the driving rotation speed in order to adjust the flow rate and pressure of fluid.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a variable displacement reciprocating piston device that can variably control the reciprocating stroke of a piston and thus the displacement with an extremely simple configuration. In particular, this invention suppresses fluctuations in the compression ratio when the capacity is increased or decreased, and at the same time, it is possible to always maintain the opening and closing timing of the intake valve and exhaust valve at the optimum timing regardless of the change in capacity. It is an object.

Means for Solving the Problems A variable displacement reciprocating piston device according to the present invention has a pin portion connected to a reciprocating piston via a connecting rod, and has sliders or guide grooves perpendicular to each other on both end surfaces. an intermediate node member formed along the direction of a first main shaft, which is in close contact with the other surface of the intermediate section member, and a second main shaft having a guide groove or a slider formed on the joint surface; The rotation center O2 is configured to be movable along a predetermined locus so that it can move toward and away from the rotation center OI of the first main shaft, and as the distance between the two rotation centers O1 and O2 decreases, 03. A movable bearing member whose movement locus of the center of rotation O2 is set so that the slope of the line connecting 〇- increases, a valve train driven by the first main shaft via a timing belt or chain, and the timing. It has a pair of guide members that regulate the movement locus of the intermediate portion of the belt or chain, and the position of the guide members is aligned with the rotation center O of the second main shaft.
, and a valve opening/closing timing correction mechanism that changes as the valves move.

Operation In the above configuration, the first main shaft, the second main shaft, and the intermediate joint member between them constitute a so-called Oldham joint, and the piston is connected to the intermediate joint member, which is the intermediate joint.

Therefore, the reciprocating stroke of the piston is approximately equal to the distance between the rotation center O1 of the first main shaft and the rotation center Ox' of the second main shaft. In other words, if the distance between the two rotation centers 0+ and Ot increases due to the movement of the movable bearing, the capacity will increase.
Conversely, if the distance becomes small, the capacity decreases.

On the other hand, when the distance between both rotation centers 0.02 is maximum, 0.02. ．． 0. The line connecting the two has a small slope and is approximately along the piston movement direction (that is, the cylinder axis). Then, when the capacity decreases, that is, 0. .

When the distance between 0.01 and 0.01 is made small, 0. ．． 0. The slope of the line connecting them will be large. As a result, the top dead center position of the piston in the latter case is higher than the top dead center position in the former case. Therefore, fluctuations in the compression ratio due to capacity reduction are reduced.

In addition, with the movement of the rotation center O2 of the second main shaft,
The position of the timing belt and chain guide members changes. As a result, one of the length on the tight side and the length on the slack side of the timing belt or chain increases, and the other decreases. As a result, the phase in the valve operating mechanism and the phase of the first main shaft change relative to each other, and the valve opening/closing timing is retarded. That is,
The phase shift between the valve mechanism and the actual piston position caused by the inclination of the line connecting Ol and Ot as described above is
Can be offset.

Embodiment FIG. 1 is an exploded perspective view of an embodiment of a variable displacement reciprocating piston device according to the present invention.

In the figure, l is the spindle case, and this spindle case l
A cylinder block 2 is mounted and fixed on the upper surface of the cylinder block.

The cylinder block 2 has a cylinder (not shown) therein, into which a piston 3 is slidably fitted. This piston 3 is connected to the small end of a connecting rod 5 via a piston pin 4. still,
A valve operating mechanism including an intake valve 41 and an exhaust valve 42 (see FIG. 2) is provided in the upper part of the cylinder block 2, but the details thereof are omitted in FIG. 1.

6 is an intermediate node member corresponding to the intermediate node in a so-called Oldham joint, and this intermediate node member 6 includes a short cylindrical pin portion 7 and a first . Second
It consists of a slider 8.9. The pin portion 7 is attached to the large end of the connecting rod 5 with a cap bolt 1.
It is rotatably held via a cap 10 fastened at 1. Said first slider 8. The second slider 9 is
They are rod-shaped with a rectangular cross section and are formed along directions perpendicular to each other.

Next, I2 indicates the first main axis corresponding to one node of the Oldham joint. This first main shaft 12 is composed of a disk portion 13 that is in close contact with the end surface of the pin portion 7, and a shaft portion 14 that is formed protrudingly from the back surface of the disk portion 13.
A guide groove 15 along the radial direction is recessed in the surface of 3. This guide groove 15 fits into the first slider 8 of the intermediate section member 6, and restricts the direction of relative movement between the two in one direction. The shaft portion 14 is rotatably supported by a fixed bearing 16 fixed to the main shaft case 1 with a bolt 17.

Further, I8 indicates a second main shaft corresponding to the other node of the Oldham joint. The second main shaft 18, like the first main shaft 12, is composed of a disc part 19 that is in close contact with the other end surface of the pin part 7, and a shaft part 20 formed on the back surface of the disc part 19, and the surface of the disc part 19 is A guide groove 21 is recessed along the radial direction. The guide groove 21 fits into the second slider 9 of the intermediate node member 6, and also restricts the direction of relative movement between the two in one direction. Then, the shaft portion 20 of the second main shaft 18
is rotatably supported by a bearing portion 23 of a bearing lever 22, which is a movable bearing member. This bearing lever 22 has a fulcrum part 24 at one end rotatably supported by a support shaft 25 of the main shaft case l, and an elongated engagement hole 26 is formed in the operating part at the other end. . That is, the bearing portion 23 is configured to move in an arcuate trajectory, and an arcuate opening 27 is provided in the spindle case l in accordance with this movement. Note that when the bearing lever 22 is pushed down to the lowest position, the rotation center O2 of the second main shaft 18 is located approximately directly below the rotation center OI of the first main shaft 12, and the bearing lever 2
When rotating 2 upward, both rotation centers 01. The configuration is such that Ot approaches.

Further, as a drive mechanism for driving the bearing lever 22, a double-acting hydraulic cylinder 28 is used in this embodiment. The hydraulic cylinder 28 includes a cylinder case 30 attached to the flange portion 29 of the main shaft case 1, a piston 31 that fits into the cylinder case 30 and separates hydraulic chambers from above and below, and one end fixed to the piston 31. and a rod 32 whose other end is connected to the engagement hole 26 of the bearing lever 22. Further, 33 is a spool valve that controls hydraulic pressure supply to the upper and lower hydraulic chambers of the double-acting hydraulic cylinder 28. It is composed of a body 35. A control lever 36 is attached to the lower end of the valve body 35.
The tips of the spool valves 33 are connected to each other, and the spool valve 33 is switched by swinging the control lever 36. Note that a support plate 37 supporting the control lever 36 as a fulcrum is fixed to the main shaft case 1.

Next, the configuration of the valve mechanism will be explained based on FIGS. 2 and 3.

As shown in FIG. 2, the valve mechanism of this embodiment has one camshaft 43, and the intake valve 4! , to open and close the exhaust valve 42. As shown in FIG. 3, the camshaft 43 has a timing pulley 46 fixed to one end, and a timing pulley 47 fixed to the end of the first main shaft 12.
A timing belt 48 is wound between the
As a result, it is driven by the first main shaft 12. In addition, in a reciprocating piston device applying this Oldham coupling, the piston 3
Since the first main shaft 12 makes one revolution in two reciprocating cycles, the number of teeth of both timing pulleys 46 and 47 will be equal when configured as a four-cycle internal combustion engine.

In addition, this valve mechanism has both timing pulleys 46 and 47.
Equipped with a valve opening/closing timing correction mechanism to change the phase of the valve. In FIG. 3, reference numerals 51 and 52 refer to rotatable guide pulleys as guide members, 53 and 54 refer to guide pulleys 51 and 52 rotatably attached to the tips thereof, and camshafts 43 and 54, respectively. 1st spindle 1
a swinging lever configured to be swingable around 2; 55;
is a link member that connects the rotating shafts 56 and 57 of both guide pulleys 51 and 52 to each other. That is, both guide pulleys 51 and 52 have the function of applying pressure to the back surface of the intermediate portion of the timing belt 48 from the outside to apply an appropriate tension, and at the same time, regulating the movement locus of the intermediate portion of the timing belt 48. , and due to the link members 55, when one moves inward, the other moves outward. Further, for example, when the guide pulley 51 side portion of the timing belt 48 is in a substantially straight line state, the other guide pulley 52 side portion is located considerably inside, and the timing belt 48 is folded relatively largely. It is in a bent state.

The center portion of the link member 55 further extends through the link member 58 to one end 59a of the abbreviated lever 59.
It is linked to. The lever 59 has a fixed shaft 60
It is rotatably supported around the other end 59b.
Furthermore, the movement of the bearing lever 22 is transmitted via a link mechanism (not shown) or the like. That is, when the bearing lever 22 rotates, the lever 5 moves according to the amount of movement.
9 rotates, and eventually the guide pulleys 51 and 52 move left and right.

Now, in the above configuration, as described above, the first main shaft 12
The second main shaft 18 and the intermediate joint member 6 constitute a so-called Oldham joint, and the large end portion of the connecting rod 5 is linked to the intermediate joint member 6 corresponding to the intermediate joint of the Oldham joint.

As shown in Figure 4, the rotation center of the first spindle I2 is set at 01%.
Second main axis! 8's rotation center is O7, and the intermediate joint member 6 (pin g
If the center of rotation of 57) is O8, then as is well known, the first main shaft 12 and the second main shaft! 8 and the intermediate node member 6 rotate in exactly the same phase, and the rotation center O1 of the intermediate node member 6 revolves on a circle R having a diameter of the line segment OIOt.

Therefore, for example, if the first main shaft 12 or the second main shaft 18 is rotationally driven from the outside as a compressor, the piston 3 will reciprocate linearly as the rotation center 03 revolves. Conversely, if the piston 3 moves linearly in a reciprocating manner in an internal combustion engine, the first main shaft 12 and the second main shaft! 8 rotates as the bottle portion 7 revolves.

As is clear from FIG. 4, the reciprocating stroke S during the reciprocating linear movement of the piston 3 is the diameter of the circle R, that is, the first . The distance is approximately equal to the distance between the rotation centers Ot and Ox of the second main shafts 12 and 18.

Therefore, by rotating the bearing lever 22 upward in FIG.
If the distance between l and Ox is made small, the reciprocating stroke S will be shortened, and conversely, by rotating the bearing lever 22 downward, the reciprocating stroke S will be shortened. If the distance between Ox is large, the reciprocating stroke S
becomes longer. This changes the capacity of the piston device, that is, the displacement amount as an internal combustion engine and the discharge amount as a compressor.

In the embodiment shown in FIG. 1, movement of the bearing lever 22 is effected by a hydraulic control mechanism using a spool valve 33 and a hydraulic cylinder 28. That is, a predetermined hydraulic pressure is introduced from a hydraulic pump (not shown) to the supply boat 38 in the center of the spool valve 33, and the spool valve 33 is switched by operating the control lever 36 to move the double-acting hydraulic cylinder 28 upward or downward. By doing so, variable control of the capacity is achieved. This variable control of the capacity can be performed at any timing without stopping the operation of the piston device.

By the way, in FIG. 4, if both rotation centers Q+, Ot
Assuming that is located above the cylinder axis M, the center of the circle R is always above the cylinder axis M, so the top dead center position of the piston 3 is at the rotation center 03 of the pin part 7. O
The piston will be in position 3 when it matches 1. In other words,
The top dead center position of the piston 3 will be fixed, which means that even if the overall capacity of the device changes, the remaining capacity at top dead center will not change, and fluctuations in the compression ratio will not be affected. It's coming. Therefore, in this invention, the top dead center position is changed at the same time to suppress fluctuations in the compression ratio. this,
This will be further explained with reference to the explanatory diagram of FIG.

First, each rotation center when the bearing lever 22 is pushed down to the lowest position is set to 0. ．． 01, the inside of the revolution at that time is R8, and the center of the inside of the revolution R is 04. In this state, the reciprocating stroke S of the piston 3 is the maximum stroke S
I, which is approximately equal to the diameter of circle R1. In this embodiment, since the so-called offset amount is O, the maximum stroke SI and the diameter of the circle R are completely equal.

In the case of the above maximum stroke S+, the top dead center position of the piston 3 is defined when the center 03 of the bottle part 7 comes to the point T on the cylinder axis M1, that is, the point O1, and the bottom dead center position is defined as , is defined when point O2 reaches point B on line M, that is, point O1. In the figure, the centers of the piston pin 4 at the top dead center and bottom dead center are shown as P, , P.

On the other hand, when the bearing lever 22 is rotated upward, the rotation center of the second main shaft 18 is 0. moves along an arcuate trajectory A. In the figure, the center of rotation at a certain rotational position is shown as Ot-, but Rt within the revolution at this time is the point 0. and point 0
．． Since it is drawn as a circle whose diameter is the line segment connecting R, as is clear from the figure, it protrudes upward in the figure from the original revolution R. In this case, the top dead center position of the piston 3 is defined when the center O1 of the bottle portion 7 comes to point T, and the bottom dead center position is defined when the point O5 comes to point B. be done. Also, the reciprocating stroke S of the piston 3
, has a value approximately equal to the diameter of R2 within the revolution. Note that the center of the piston pin 4 at the top dead center position is shown as P, -.

Therefore, as is clear from the positional relationship between the point T that defines the top dead center and the point Td, the reciprocating stroke is S! , :The top dead center position of the piston 3 when the reciprocating stroke is S
It will move above the top dead center position when it is l. In other words, the remaining capacity at top dead center decreases accordingly.

In other words, a decrease in compression ratio due to a decrease in total capacity is suppressed.

The above movement amount α of the top dead center position is approximated by the distance of the points T, , Tt along the cylinder axis M1 direction, so the points 0+,
It can be determined as α=S(1-cosφ)/2, where the angle formed by the line M connecting Ot- and the line M is φ.

In short, the reciprocating stroke S (that is, the diameter of the revolution inside R)
The center of rotation O becomes larger as the angle φ becomes smaller.
By setting the movement trajectory A of No. 2, the top dead center, where the capacity becomes smaller, moves upward, making it possible to suppress fluctuations in the compression ratio within a small range.

Note that the ideal movement trajectory A varies depending on the shape of the upper part of the cylinder, the compression ratio, etc. Therefore, in the above embodiment, the locus is arcuate, but it goes without saying that the locus is not limited to this.

On the other hand, if the position of the top dead center changes as described above, the phase of the valve mechanism will shift.

That is, when the rotation center of the second main shaft 18 is located at 0ffi'', the actual top dead center is located at the bottle portion 7, as described above.
When the center Os comes to point T, the valve mechanism is
If it is driven in the same phase as the main shaft 12, the center of the pin part 7 is 0.
3 reaches the point Ts, the guide groove 15 of the first main shaft 12 is in a state perpendicular to the line segments 0 and O1, so this point T3 position becomes the top dead center position in terms of the phase in the valve mechanism. Therefore, if the pin portion 7 and the like rotate clockwise in FIG. 5, the valve opening/closing timing will be advanced by an angle θ.

On the other hand, in the valve operating mechanism configured as described above, the above-described phase shift is offset by the valve opening/closing timing correction mechanism provided for the timing belt 48.

FIG. 6 is an explanatory diagram for explaining this phase correction, and the broken line in the diagram indicates when the reciprocating stroke S of the piston 3 is the maximum stroke Sl, that is, in FIG. 5, the center of the second main shaft 18 is The state of the timing belt 48 and the like when located at point O1 is shown. Also, the solid line is the reciprocating stroke S
becomes smaller, that is, in Fig. 5, the second principal axis 1
The center of 8 is point 0! - shows the state of the timing belt 48 etc. when located at -. In addition, both timing pulleys 46.4
7 is assumed to rotate in the clockwise direction, for example, as in FIG.

That is, in the above rotation direction, the guide pulley 51 side is the belt tension side and the guide pulley 58 side is the belt slack side, but in the state of the maximum stroke Sl shown by the broken line, the guide pulley 51 is pushed inward. Located in
The belt base on the tight side is large, and the belt base on the loose side is small in comparison.

From this state, as the reciprocating stroke S decreases, both guide pulleys 51 and 52 move to the positions shown by the solid lines, that is, the tight guide pulley 51 moves outward and the loose guide pulley 52 moves inward. As the tension increases, the number of belt bases on the tight side decreases and the number of belt bases on the loose side increases.

Therefore, as the belt base changes, the driven pulley, the timing pulley 46 on the camshaft 43 side, rotates counterclockwise relative to the driving side timing pulley 47, as shown in the figure. The phase is delayed by an angle θ1. Therefore, if each part is set so that the phase advance θ due to the change in the top dead center position described above and this phase lag θ are approximately equal, then the phase change θ due to the change in the top dead center position described above can be reduced. This can offset the effects and prevent deviations in valve opening/closing timing.

Note that the above correction amount θ for the valve opening/closing timing is based on the guide pulley 5.
By continuously changing the positions of 1 and 52, the piston stroke S can be changed continuously in the same manner as the piston stroke S.

Therefore, no matter how the piston stroke S is changed, the optimum valve opening/closing timing can always be ensured accordingly. Further, when the ignition timing is controlled by the phase of the camshaft 43, the ignition timing can always be maintained in an optimal state.

In the above embodiment, the first section is provided on the intermediate section member 6 side. A second slider 8.9 is provided protrudingly from the first main shaft 12.9. Although the guide grooves 15 and 21 are recessed on the second main shaft 18 side, this relationship can be changed as appropriate. In other words, the intermediate section member 6 and the first section member 6.
It is only necessary that the movement directions with respect to the second main shafts 12 and 18 can be restricted to one direction.

Further, in the above embodiment, an embodiment of a single cylinder piston device has been described, but it goes without saying that this can be used by connecting a plurality of cylinders.

Effects of the Invention As is clear from the above explanation, according to the variable displacement reciprocating piston device according to the present invention, the reciprocating stroke of the piston can be changed while the operation continues, and the displacement can be changed at any timing. can be controlled.

When the reciprocating stroke of the piston decreases, the top dead center position of the piston changes upward at the same time, so it is possible to suppress fluctuations in the compression ratio due to changes in displacement.

At the same time, the phase of the valve mechanism can be corrected to offset the phase shift caused by the change in the piston top dead center position, and the opening and closing timing of the intake and exhaust valves can always be kept at the appropriate timing. can·

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an embodiment of a variable displacement reciprocating piston device according to the present invention, FIG. 2 is a sectional view of its valve mechanism, and FIG. 3 is a diagram of the valve mechanism and valve timing correction mechanism. An exploded perspective view, FIG. 4 is an explanatory diagram for explaining the operating principle of the piston device, FIG. 5 is an explanatory diagram for explaining the operating principle in more detail, and FIG. 6 is an illustration of the operation of the valve timing correction mechanism. FIG. 3 is an explanatory diagram for explaining the principle. 3...Piston, 5...Connecting rod, 6
... intermediate node member, 7 ... pin part, 8 ... first slider, 9 ... second slider, 12 ... first main shaft, 1
5... Guide groove, I6... Fixed bearing, 18... Second main shaft, 21... Guide groove, 22...-Bearing lever,
43...Camshaft, 46.47...Timing pulley, 48...Timing belt, 51.52...
・Guide pulley. 43...Camshaft Figure 4

Claims (1)

[Claims] (1) An intermediate node member having a pin portion connected to a reciprocating piston via a connecting rod, and having sliders or guide grooves formed on both end faces along directions orthogonal to each other; A first main shaft that is in close contact with one end surface of the member, a guide groove or a slider is formed in the radial direction on the joint surface thereof, and whose rotation center O_1 is fixed, and a first main shaft that is in close contact with the other surface of the intermediate joint member. and a second main shaft having a guide groove or a slider formed on its joint surface, and the second main shaft is rotatably supported, and its rotation center O_2 approaches and moves away from the rotation center O_1 of the first main shaft. The center of rotation O_2 is configured to be movable along a predetermined trajectory as possible, and the center of rotation O_2 is moved so that the slope of the line connecting O_1 and O_2 increases as the distance between the two centers of rotation O_1 and O_2 decreases. A movable bearing member having a set locus, a valve mechanism driven by the first main shaft via a timing belt or chain, and a pair of guide members regulating the movement locus of an intermediate portion of the timing belt or chain. and a valve opening/closing timing correction mechanism in which the position of the guide member changes with movement of the rotation center O_2 of the second main shaft.