Power-cam mechanism
(Updated on 05 July 2020) Power-cam is a part of the patent WO2015120530 (the patent file). But, it can be used in all mechanical fields. It is an improvement of conventional cam mechanism.
Conventional cam mechanism, showing in fig. 1, is a widely used in all mechanical fields. The cam is a rotating piece in a mechanical linkage, used commonly in transforming rotary motion into linear motion. Because of the sliding frictions, especially between the follower and the shell, its mechanical efficiency is low. It only suits for motion transforming rather than driving force transforming. It suits for the cam driving the follower, and it does not suit for the follower driving the cam.
However, the power-cam mechanism, showing in fig. 2 to 6, uses rolling as much as possible to instead of sliding to reduce friction, especially between the follower and the shell. It is suitable for driving force transforming as well as motion transforming. A power-cam can drive the follower also the follower can drive the power-cam, by high mechanical efficiency.
The video (or in China https://v.youku.com/v_show/id_XMTUyMTQ4MTQ4OA==.html?from=s1.8-1-1.2) shows the power-cam motion and the toothed-rollers' motion.
Power-cam mechanism comprises power-cam, follower, shell, and toothed-roller arrays, shown in fig. 2.
The power-cam, which rotates round the axle center, drives the follower in reciprocation motion along a straight line or an arc; and vice versa. The shell and the axle center are stationary.
A toothed-roller is a roller with many teeth, or rather, a toothed-roller has one bearing surface and many teeth; a toothed-roller array is that many toothed-rollers are restricted and synchronized by a cage; shown in fig. 3.
A toothed-track has one bearing surface, and has many teeth on its edge. The bearing surface is for toothed-rollers, rolling on. The teeth are for meshing with the teeth of toothed-rollers.
While they are working, the synchronized toothed-rollers, roll between the toothed-tracks of the follower and the shell (Detail A of fig. 3), withstand the normal force by their bearing surface contacting, and mesh their teeth, to ensure the toothed-rollers always rolling and no sliding, and to prevent the toothed-rollers from sliding to a wrong position.
If a power-cam mechanism is good design and manufactured — If the toothed-rollers bear enough normal force, their teeth bear zero force; If the toothed-rollers bear zero normal force, their teeth bear the inertia force of the toothed-rollers.
Thus, power-cam mechanism has very few sliding frictions, which includes — between toothed-rollers and their cage, and between meshing teeth. The else frictions are all rolling. Therefore, the power-cam and the follower can drive each other in very high mechanical efficiency. Its mechanical efficiency is much higher than conventional cam mechanism and most crank-link mechanism. Based on this, we use power-cam instead crankshaft to create Zhou Engine.
The tracks of the power-cam may be very complicated, that means the relationship between the follower motion and power-cam rotation is very complicated.
Seeing the fig.6, while the design of a power-cam mechanism, the bearing surface of wheel A, the bearing surface of wheel B, the track surface, their strength and modulus of elasticity influence the power density of the device. We hope they have higher strength and lower modulus of elasticity. We can choose titanium alloy to make their parts or the region of their parts.
Power-cam mechanism has many uses in all mechanical fields. It has far more uses than conventional cam mechanism, and far more uses than on Zhou Engine. For example, imitating “turbocharged Zhou Engine”, we can create piston pumps or compressors with steady flow.
Because of the experience of our using of a conventional cam mechanism, we have had “A Typical Style of Thinking”, which limits the ability of our thinking. Please see “An Inertial Thinking on Cam Mechanism”.
For more about this patent, please read “About Zhou Engine”.
发明“周引擎”，我正寻求合作伙伴和资金支持。
8 年Hi Jody, Thank you very much for your interest in this issue. The pitch diameter of a toothed-roller is very easy matching its roller. Don’t worry about it. See the following: 1. As a normal design, the pitch diameter of a toothed-roller should equal its roller diameter, and its teeth profile is involute. The module of its teeth can be arbitrarily selected, and does not matter of stroke length. Therefore, the toothed-roller rolls only, and has no sliding. 2. For easy manufacturing a toothed-roller, we should manufacture the roller and gear wheel, and then assemble them together. We can set them “solid assembling” or “rotatable assembling”. 3. If we choose “solid assembling” of a toothed-roller, for example, a 100 mm stroke, and 8.00 mm diameter of toothed-roller with 10 teeth, f is the pure sliding friction parameter between the roller and the track. Then the module of teeth is 8/10=0.8. If the toothed-roller wears, the diameter of its roller changes from 8.00 mm to 7.9 mm, and the module of the teeth does not change, then the toothed-roller will have a little sliding, each 100 mm stroke will slide 100*(8-7.9)/8=1.25 mm. It means, the roller rotates the same angle, and moves the same distance, and rolls distance smaller. Or rather, since the toothed-roller wears, the additional friction parameter between the toothed-roller and toothed-track is f*(8-7.9)/8=f/80, which is far less than pure sliding friction f. 4. If we choose “rotatable assembling” of a toothed-roller; while it is new, the roller and the gear wheel have no rotate relative; while the roller wears, they are a litter rotate relative, we need not to special lubricate the rotate. 5. We can set the toothed-track a litter bit longer to avoid the toothed-roller out of place. 6. You said, “It may be better to have a cage only, and no teeth. Only occasional sliding if the cage hits the end.” I don’t think so. The occasional large enough sliding of the rollers will break the function, the rollers and the track will be worn out serious, and the machine will stop working. The accumulating effect of the occasional sliding of the rollers will increase their worn out.
Electro Mechanical Design and Analysis
8 年the difficulty with toothed rollers is that the pitch diameter of the teeth must exactly match the diameter of the roller. As the roller wears out, it turns through a larger angle, but the teeth wont let it. for example, assume a 100mm stroke, and a 2.00 mm diameter roller with 10 teeth How many revolutions per stroke? 100/2/2.00/pi = 7.96 revolutions, or 79.6 teeth Now after being used, the roller wears to 1.99 mm diameter 100/2/1.99/pi = 7.99 or 79.9 teeth, so the rollers will be .3 teeth out of place, which means they will slide, and therefore wear faster. I'm guessing at the stroke and roller size. What happens with the actual sizes you are considering? it may be better to have a cage only, and no teeth. only occasional sliding if the cage hits the end.