Piston Mechanism

Abstract

Provided is a piston mechanism comprising: a piston; a rotating element rotatable about an axis and having a first engagement profile; a first connecting element coupled to the piston; a second connecting element pivotable about a fixed point and pivotally connected to the first connecting element; and a mechanism coupled to the first and / or second connecting element, the mechanism comprising a second engagement profile configured to mechanically engage and disengage with the first engagement profile of the rotating element.

Description

[Technical field]

[0001] The present invention relates to a piston mechanism and to an internal combustion engine incorporating said mechanism. [Background technology]

[0002] Most engines that use the expansion of a fluid to drive a piston use a crankshaft coupled to the piston through a connecting rod to convert the reciprocating motion of the piston into rotational motion. Another mechanism for transmitting power from the piston to a rotating shaft has been disclosed in which the piston is connected to a track by a follower (see U.S. Pat. No. 5,393,633). However, improved power transmission from the piston to the rotating shaft is possible. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 107330 Summary of the Invention [Means for solving the problem]

[0004] According to an aspect of the present invention there is provided a piston mechanism as defined in claim 1.

[0005] Such an arrangement allows the piston and rotating element to be coupled for a greater portion of the piston's drive stroke, i.e., a greater portion of the power from the piston can be transferred to the rotating element, thereby achieving a more efficient power transfer overall.

[0006] The second engagement profile may include a plurality of second teeth. Such a feature may reduce wear on the second engagement profile.

[0007] At least two of the teeth can have different dimensions such that the surfaces can be configured to each engage the second engagement profile at an optimal angle.

[0008] Similarly, the first engagement profile may include a plurality of first teeth, the plurality of second teeth allowing for reduced wear on each tooth.

[0009] The first and second engagement profiles may form a rack and sector gear mechanism.

[0010] When the first and second engagement profiles engage, the engagement can occur at a location between the fixed point and the axis of rotation of the rotating element, such an arrangement allowing the second connecting element to be compressed to more reliably keep the two engagement profiles engaged.

[0011] When the first and second engagement profiles are engaged, the second coupling member can rotate in a first angular direction about a fixed point and the rotating element can rotate in a second angular direction about an axis, the first angular direction being opposite to the second angular direction. Such a mechanism allows the two engagement profiles to move in an arc that only engages where necessary during the piston cycle, thereby achieving improved engagement of the two profiles.

[0012] The piston mechanism may further comprise a track arranged to rotate about a track axis, the piston being coupled to said track such that the track and the rotating element rotate together, such that the track allows for more customized movement of the piston during strokes other than the drive stroke.

[0013] The piston may be coupled to the track via a follower coupled to the first and / or second coupling element, the follower arranged to run along a surface of the track. The use of the first coupling element to couple the track to the piston means that no specific additional parts are required to couple the piston to the track and therefore such an arrangement may provide weight savings.

[0014] The follower may be positioned to be coupled to the first and second connecting elements at a pivot connection between the first and second connecting elements, or alternatively, the follower may be coupled to the second connecting element at a point remote from the pivot connection between the first and second connecting elements.

[0015] The piston mechanism may further comprise a further plurality of followers, each of which is arranged to run along the surface of a single track and / or a plurality of coaxial tracks. The use of multiple followers and multiple tracks may allow for reduced wear on each track and each follower.

[0016] The piston mechanism may have a single follower disposed between a radially outer track and a radially inner track, or it may have a single track having a radially outer surface and a radially inner surface and two or more followers with at least one follower running along each surface of the track.

[0017] The track may be formed as an elongated projection from a plate, the plate being substantially flat in a plane perpendicular to the track axis, and thus the track may be formed resiliently, or alternatively the track may be formed as a channel recessed into the plate.

[0018] The track can be shaped such that the motion of a piston coupled to the track is substantially non-harmonic, which can allow for more customisation of the piston motion.

[0019] The piston can perform two reciprocating motions per revolution of the rotating element, which allows the piston mechanism to be used in four-stroke engines.

[0020] The piston may be a first piston, and the piston mechanism further comprises a second piston movable within a respective cylinder, another first connecting element connected to the second piston, and another second connecting element pivotable about a second fixed point, and the rotating element is configured to mechanically engage and disengage with each of both first connecting elements.

[0021] The second piston and the first piston may be disposed in opposing relationship to form a balanced piston mechanism.

[0022] According to a second aspect of the present invention, there is provided an internal combustion engine comprising a piston mechanism according to the first aspect.

[0023] According to a third aspect of the invention there is provided a piston mechanism comprising a piston, a rotating element comprising a track and rotatable about an axis, a first connecting element connected to the piston, a second connecting element pivotable about a fixed point and pivotally connected to the first connecting element, and a mechanism comprising a first follower arranged to follow the track and coupled to the second connecting element.

[0024] In such a mechanism, the rotating element of the piston mechanism does not need to have an element that engages and disengages with a connecting element, instead the transmission of force to the rotating element can be by a follower that engages with the track through one complete revolution.

[0025] The third aspect of the invention may, if desired, incorporate any of the features of the first aspect of the invention. [Brief description of the drawings]

[0026] [Figure 1] FIG. [Diagram 2] FIG. 1 is a diagram of the engine with various components omitted. [Diagram 3] FIG. 2 is a diagram of a first piston mechanism. [Figure 4] FIG. 11 is a diagram of a second piston mechanism. [Diagram 5] FIG. 11 is a diagram of a third piston mechanism. [Figure 6] FIG. 13 is a diagram of a fourth piston mechanism. [Figure 7] FIG. 5 is a diagram of a fifth piston mechanism. [Figure 8] FIG. 6 is a diagram of a sixth piston mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0028] 1 shows an internal combustion engine 10 that includes a cylinder block assembly 12 and two head assemblies 14. The block assembly 12 includes a number of casing members or plates having various shapes that, when assembled, form the cylinder block 12.

[0029] FIG. 2 shows the engine 10 with the head assembly 14 removed. The head assembly has cylinder bores, each of which receives a respective cylinder liner, which in turn receives a respective piston. In this view, pistons 18 can be seen protruding from the cylinder block 12. The engine 10 has a total of four pistons connected in opposing relationship to two tracks (not shown in FIG. 2). Thus, the engine 10 includes four piston assemblies, and while the structure and function of the first piston assembly will be described in detail, it should be understood that the second, third, and fourth piston assemblies are similar in structure and function to the first piston assembly. Although four pistons 18 are shown in FIG. 2, it should be understood that any other number of pistons may be used, for example, two pistons or eight pistons.

[0030] Figure 3 shows a piston mechanism according to the invention. In Figure 3, a piston 118 is shown reciprocating in a cylinder. The piston 118 is connected to a first connecting member 120 via a pivot pin 119. At the opposite end of the first connecting member 120, the elongated connecting member 120 is connected to a second connecting member 130 by a second sliding pin 121. The second connecting member 130 is pivotally fixed at a point 132, thereby forming a mechanism together with the first connecting member 120 and the piston 118.

[0031] Point 132 is fixed relative to the cylinder in which piston 118 reciprocates. It is understood that the engine may move, such as in a vehicle, but there is no relative movement between point 132 and the cylinder.

[0032] The first coupling member 120 further comprises an engagement profile 122 that engages with a second engagement profile 124 that is coupled to a rotation element 123 that is rotatable about an axis A1.

[0033] Point 132 and axis A1 do not move relative to each other.

[0034] The first engagement profile 122 comprises a plurality of engagement surfaces 122A and primary engagement surfaces 122B. As can be seen, the engagement surfaces 122A are separated by various pitches, have various magnitudes, and have various inclinations relative to the first connecting element 120. This variation in characteristics between the two ends of the engagement profile allows the first engagement profile 122 and the second engagement profile 124 to remain engaged as the mechanism formed by the piston 118, the first connecting member 120, and the second connecting member 130 is moved by the piston drive store. It can also be seen that the first primary engagement surface 122B is at the extreme end of the first connecting member 120, so that engagement and power transmission with the second primary engagement profile 124A can occur earlier in the piston drive or expansion stroke.

[0035] The rotating element 123 includes a second engagement profile 124 that includes a plurality of second engagement surfaces 124A that engage with respective engagement surfaces 122A of the first engagement profile. The engagement profile 124 also includes second primary engagement surfaces 124B that engage with primary engagement surfaces 122B of the first engagement profile. The second engagement profile 122 can be seen to extend around approximately 25% of the circumference of the rotating element 123.

[0036] Although the illustrated engagement profiles each have multiple engagement surfaces, a single engagement surface on the first coupling member 120 and a single engagement surface on the rotating element 123, such as a single tooth and slot arrangement, may be sufficient to effect power transmission.

[0037] The piston mechanism also includes a track 126 and a follower 128 configured to roll along the track 126. A sliding follower that slides along the track 126 can also be used. The follower 128 is coupled to the first connecting member 120, and the action of the track 126 and the follower 128 can move the piston 118 on the return stroke, and the track 126 can be configured in any way to have different speeds for different strokes of the cycle. For example, substantially non-simple harmonic motion of the piston is possible with the track and follower mechanism.

[0038] Figure 4 shows yet another development of the piston mechanism shown in Figure 3. In this mechanism, similar parts are given corresponding reference numbers and, for the sake of brevity, the description of parts that remain unchanged will not be repeated here.

[0039] A rotation element 223 which rotates about axis A2 is made integral with the engagement profile 224. However, the rotation element 123 of figure 3 can be used in this case as well.

[0040] The second connecting element 230 is modified to have a third engagement profile 225. The third engagement profile 225 aligns with the first engagement profile 222 at the time the third engagement profile 225 and the first engagement profile 222 engage with the first engagement profile 224. Forces exerted on the rotating element 223 can thereby be distributed across both the second and third engagement profiles 222, 225.

[0041] Although connection 219 is shown as a pin connection, it is equally possible for the connection to be translational rather than rotational, in a direction perpendicular to the direction of piston movement.

[0042] Turning to FIG. 5, the mechanism shown in FIG. 4 is modified so that only the third engagement profile 325 engages the rotation element 323 rotatable about the axis A3. The second connecting member 330 is formed of three individual members. The first member 330a extends from the pivot point 332 to a pin joint connecting to the first connecting member 320, the second member 330b extends between the pivot point 332 and the third engagement profile 325, and the third member 330c extends between the engagement profile 325 and the joint point 321 between the first connecting member 320 and the second connecting member 330. To reduce weight, there are hollow spaces between the first, second and third members 330a, 330b, 330c. The pivot point 332 of the second connecting member 330 is approximately 45° away from the piston, measured at the axis A3. Moving the pivot point 332 closer to the piston 318 results in a longer lever arm at the beginning of the piston 318 drive stroke.

[0043] As can be seen in FIG. 5, the first engagement portion 324 of the rotating element 323 has been shifted to engage with the third engagement portion 325 .

[0044] 6, the second connecting member 430 is reshaped to have a central block with a third engagement portion 425, with a first member 430a extending from the central portion to a pivot point 432 and a second member 430b extending from the central portion to the pin connection 421. Also note that the follower 428 is located on the second member 430 rather than on the first connecting member 420.

[0045] The first engagement portion 425 is reshaped to fit over the second engagement portion 424, which is formed as a substantially cylindrical bearing.

[0046] The first engagement portion 425 may be formed as a roller and the second engagement portion 424 may be formed as a track.

[0047] In any of the above embodiments, the follower can be in the form of one or more rollers disposed on the pivot pin between the first and second connecting members. The follower can be a single roller disposed between the two tracks (i.e., a radially inner track and a radially outer track), or it can be two rollers, one that engages the radially inner surface of the track and one that engages the radially outer track.

[0048] 7 shows a piston mechanism having a first linking member 520 pivotally coupled to a second linking member 530 at a pivot point 521, and a follower 528 disposed at the pivot point 521, the follower arranged to follow a track 526. The follower 528 may be a wheel or roller mounted on a pivot pin that also extends through the first and second linking members 520, 530.

[0049] The second connecting member 530 also has an engagement profile 525 that engages the engagement profile 524 which rotates with the track 526 about the axis A5.

[0050] The second connecting member 530 is pivotable about a fixed pivot point 532 and has holes 531 allowing for weight reduction.

[0051] Figure 8 shows a piston mechanism that does not have an engagement profile on the first or second connecting element or the rotating element. In the mechanism shown in Figure 8, the transmission of force between the rotating element and the piston 618 is by means of followers 628, 628a and tracks 626.

[0052] The first follower 628 is disposed at the pivot joint 621 between the first connecting member 620 and the second connecting member 630, and the second follower 628a is disposed on the second connecting member 630 and is attached via a pivot pin 629 that extends through the second member 630. Note that the pivot pin 629 does not extend through the first connecting member 620.

[0053] The piston mechanism has a single track 626 with first and second followers 628, 628a disposed on either side of the track. Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications can be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. A piston mechanism for transmitting power from a piston to a rotating element, comprising: A piston that reciprocates within a cylinder; a rotation element rotatable about an axis and having a first engagement profile; a track arranged to rotate about a track axis; a first coupling element pivotally coupled to the piston at a first end and movable with the piston; a second connecting element pivotally connected at a second end to the first connecting element, the second connecting element being pivotable about a fixed point, the fixed point not moving relative to the axis about which the rotating element can rotate; and a second engagement profile coupled directly to the first and / or second coupling element and configured to mechanically engage and disengage with the first engagement profile of the rotating element; have The mechanism, Equipped with the first engagement profile and the second engagement profile move in an arc and are mechanically engaged during only a portion of the piston cycle; the piston is coupled to the track; A piston mechanism in which the track and the rotating element rotate together.

2. 2. The piston mechanism of claim 1, wherein said second engagement profile comprises a plurality of second teeth.

3. A piston mechanism according to claim 2, wherein at least two of said second teeth have different sizes.

4. A piston mechanism according to claim 2 or 3, wherein the second plurality of teeth are arranged as a rack.

5. A piston mechanism according to any one of claims 1 to 4, wherein the first engagement profile comprises a plurality of first teeth.

6. A piston mechanism according to any one of claims 1 to 5, wherein the rotating element is a sector gear.

7. A piston mechanism according to any one of claims 1 to 6, wherein the first engagement profile and the second engagement profile engage at a point between the fixed point and the axis.

8. 8. A piston mechanism according to any one of claims 1 to 7, wherein when the first engagement profile and the second engagement profile are engaged, the second connecting element rotates in a first angular direction about the fixed point and the rotating element rotates in a second angular direction about the axis, the first angular direction being opposite to the second angular direction.

9. the piston is coupled to the track via a follower coupled to the first and / or second coupling element; A piston mechanism as claimed in any preceding claim, wherein the follower is arranged to run along a surface of the track.

10. 10. A piston mechanism according to claim 9, wherein the follower is coupled to the first and second connecting elements at a pivot connection between the first and second connecting elements.

11. 11. A piston mechanism according to any one of claims 1 to 10, wherein the track is shaped such that movement of the piston coupled to the track is substantially non-monoharmonic.

12. 12. A piston mechanism as claimed in any one of the preceding claims, wherein the piston performs two reciprocating motions for every rotation of the rotating element.

13. the piston is a first piston, A second piston; another first connecting element connected to the second piston; a second connecting element pivotally connected to the first connecting element, the second connecting element being pivotable about a second fixed point; Further equipped with 13. A piston mechanism according to any one of the preceding claims, wherein the rotating element is configured to mechanically engage and disengage with each of the first coupling elements.

14. 14. The piston mechanism according to claim 13, wherein the second piston and the first piston are disposed in opposing relationship.

15. An internal combustion engine comprising a piston mechanism according to any one of claims 1 to 14.

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